Sample records for effect modeling experiments

  1. Anatomical knowledge gain through a clay-modeling exercise compared to live and video observations.

    PubMed

    Kooloos, Jan G M; Schepens-Franke, Annelieke N; Bergman, Esther M; Donders, Rogier A R T; Vorstenbosch, Marc A T M

    2014-01-01

    Clay modeling is increasingly used as a teaching method other than dissection. The haptic experience during clay modeling is supposed to correspond to the learning effect of manipulations during exercises in the dissection room involving tissues and organs. We questioned this assumption in two pretest-post-test experiments. In these experiments, the learning effects of clay modeling were compared to either live observations (Experiment I) or video observations (Experiment II) of the clay-modeling exercise. The effects of learning were measured with multiple choice questions, extended matching questions, and recognition of structures on illustrations of cross-sections. Analysis of covariance with pretest scores as the covariate was used to elaborate the results. Experiment I showed a significantly higher post-test score for the observers, whereas Experiment II showed a significantly higher post-test score for the clay modelers. This study shows that (1) students who perform clay-modeling exercises show less gain in anatomical knowledge than students who attentively observe the same exercise being carried out and (2) performing a clay-modeling exercise is better in anatomical knowledge gain compared to the study of a video of the recorded exercise. The most important learning effect seems to be the engagement in the exercise, focusing attention and stimulating time on task. © 2014 American Association of Anatomists.

  2. Modeling the Interplay Between Psychological Processes and Adverse, Stressful Contexts and Experiences in Pathways to Psychosis: An Experience Sampling Study

    PubMed Central

    Klippel, Annelie; Myin-Germeys, Inez; Chavez-Baldini, UnYoung; Preacher, Kristopher J.; Kempton, Matthew; Valmaggia, Lucia; Calem, Maria; So, Suzanne; Beards, Stephanie; Hubbard, Kathryn; Gayer-Anderson, Charlotte; Onyejiaka, Adanna; Wichers, Marieke; McGuire, Philip; Murray, Robin; Garety, Philippa; van Os, Jim; Wykes, Til; Morgan, Craig

    2017-01-01

    Abstract Several integrated models of psychosis have implicated adverse, stressful contexts and experiences, and affective and cognitive processes in the onset of psychosis. In these models, the effects of stress are posited to contribute to the development of psychotic experiences via pathways through affective disturbance, cognitive biases, and anomalous experiences. However, attempts to systematically test comprehensive models of these pathways remain sparse. Using the Experience Sampling Method in 51 individuals with first-episode psychosis (FEP), 46 individuals with an at-risk mental state (ARMS) for psychosis, and 53 controls, we investigated how stress, enhanced threat anticipation, and experiences of aberrant salience combine to increase the intensity of psychotic experiences. We fitted multilevel moderated mediation models to investigate indirect effects across these groups. We found that the effects of stress on psychotic experiences were mediated via pathways through affective disturbance in all 3 groups. The effect of stress on psychotic experiences was mediated by threat anticipation in FEP individuals and controls but not in ARMS individuals. There was only weak evidence of mediation via aberrant salience. However, aberrant salience retained a substantial direct effect on psychotic experiences, independently of stress, in all 3 groups. Our findings provide novel insights on the role of affective disturbance and threat anticipation in pathways through which stress impacts on the formation of psychotic experiences across different stages of early psychosis in daily life. PMID:28204708

  3. Estimates of effects of residual acceleration on USML-1 experiments

    NASA Technical Reports Server (NTRS)

    Naumann, Robert J.

    1995-01-01

    The purpose of this study effort was to develop analytical models to describe the effects of residual accelerations on the experiments to be carried on the first U.S. Microgravity Lab mission (USML-1) and to test the accuracy of these models by comparing the pre-flight predicted effects with the post-flight measured effects. After surveying the experiments to be performed on USML-1, it became evident that the anticipated residual accelerations during the USML-1 mission were well below the threshold for most of the primary experiments and all of the secondary (Glovebox) experiments and that the only set of experiments that could provide quantifiable effects, and thus provide a definitive test of the analytical models, were the three melt growth experiments using the Bridgman-Stockbarger type Crystal Growth Furnace (CGF). This class of experiments is by far the most sensitive to low level quasi-steady accelerations that are unavoidable on space craft operating in low earth orbit. Because of this, they have been the drivers for the acceleration requirements imposed on the Space Station. Therefore, it is appropriate that the models on which these requirements are based are tested experimentally. Also, since solidification proceeds directionally over a long period of time, the solidified ingot provides a more or less continuous record of the effects from acceleration disturbances.

  4. Challenging terrestrial biosphere models with data from the long-term multifactor Prairie Heating and CO2 Enrichment experiment

    NASA Astrophysics Data System (ADS)

    De Kauwe, M. G.; Medlyn, B.; Walker, A.; Zaehle, S.; Pendall, E.; Norby, R. J.

    2017-12-01

    Multifactor experiments are often advocated as important for advancing models, yet to date, such models have only been tested against single-factor experiments. We applied 10 models to the multifactor Prairie Heating and CO2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were to investigate how multifactor experiments can be used to constrain models and to identify a road map for model improvement. We found models performed poorly in ambient conditions: comparison with data highlighted model failures particularly with respect to carbon allocation, phenology, and the impact of water stress on phenology. Performance against the observations from single-factors treatments was also relatively poor. In addition, similar responses were predicted for different reasons across models: there were large differences among models in sensitivity to water stress and, among the nitrogen cycle models, nitrogen availability during the experiment. Models were also unable to capture observed treatment effects on phenology: they overestimated the effect of warming on leaf onset and did not allow CO2-induced water savings to extend the growing season length. Observed interactive (CO2 × warming) treatment effects were subtle and contingent on water stress, phenology, and species composition. As the models did not correctly represent these processes under ambient and single-factor conditions, little extra information was gained by comparing model predictions against interactive responses. We outline a series of key areas in which this and future experiments could be used to improve model predictions of grassland responses to global change.

  5. Development of the Play Experience Model to Enhance Desirable Qualifications of Early Childhood

    ERIC Educational Resources Information Center

    Panpum, Watchara; Soonthornrojana, Wimonrat; Nakunsong, Thatsanee

    2015-01-01

    The objectives of this research were to develop the play experience model and to study the effect of usage in play experience model for enhancing the early childhood's desirable qualification. There were 3 phases of research: 1) the document and context in experience management were studied, 2) the play experience model was developed, and 3) the…

  6. An Experimental Test of the Contingency Model of Leadership Effectiveness.

    ERIC Educational Resources Information Center

    Chemers, Martin M.; Skrzypek, George J.

    The present experiment provided a test of Fiedler's (1967) Contingency Model of Leadership Effectiveness, i.e., the relationship of leader style to group effectiveness is mediated by situational demands. Thirty-two 4 man task groups composed of military academy cadets were run in the experiment. In accordance with the Contingency Model, leaders…

  7. A quantum probability account of order effects in inference.

    PubMed

    Trueblood, Jennifer S; Busemeyer, Jerome R

    2011-01-01

    Order of information plays a crucial role in the process of updating beliefs across time. In fact, the presence of order effects makes a classical or Bayesian approach to inference difficult. As a result, the existing models of inference, such as the belief-adjustment model, merely provide an ad hoc explanation for these effects. We postulate a quantum inference model for order effects based on the axiomatic principles of quantum probability theory. The quantum inference model explains order effects by transforming a state vector with different sequences of operators for different orderings of information. We demonstrate this process by fitting the quantum model to data collected in a medical diagnostic task and a jury decision-making task. To further test the quantum inference model, a new jury decision-making experiment is developed. Using the results of this experiment, we compare the quantum inference model with two versions of the belief-adjustment model, the adding model and the averaging model. We show that both the quantum model and the adding model provide good fits to the data. To distinguish the quantum model from the adding model, we develop a new experiment involving extreme evidence. The results from this new experiment suggest that the adding model faces limitations when accounting for tasks involving extreme evidence, whereas the quantum inference model does not. Ultimately, we argue that the quantum model provides a more coherent account for order effects that was not possible before. Copyright © 2011 Cognitive Science Society, Inc.

  8. Effects of Repetition Priming on Recognition Memory: Testing a Perceptual Fluency-Disfluency Model

    ERIC Educational Resources Information Center

    Huber, David E.; Clark, Tedra F.; Curran, Tim; Winkielman, Piotr

    2008-01-01

    Five experiments explored the effects of immediate repetition priming on episodic recognition (the "Jacoby-Whitehouse effect") as measured with forced-choice testing. These experiments confirmed key predictions of a model adapted from D. E. Huber and R. C. O'Reilly's (2003) dynamic neural network of perception. In this model, short prime durations…

  9. General Framework for Effect Sizes in Cluster Randomized Experiments

    ERIC Educational Resources Information Center

    VanHoudnos, Nathan

    2016-01-01

    Cluster randomized experiments are ubiquitous in modern education research. Although a variety of modeling approaches are used to analyze these data, perhaps the most common methodology is a normal mixed effects model where some effects, such as the treatment effect, are regarded as fixed, and others, such as the effect of group random assignment…

  10. Challenging terrestrial biosphere models with data from the long-term multifactor Prairie Heating and CO2 Enrichment experiment.

    PubMed

    De Kauwe, Martin G; Medlyn, Belinda E; Walker, Anthony P; Zaehle, Sönke; Asao, Shinichi; Guenet, Bertrand; Harper, Anna B; Hickler, Thomas; Jain, Atul K; Luo, Yiqi; Lu, Xingjie; Luus, Kristina; Parton, William J; Shu, Shijie; Wang, Ying-Ping; Werner, Christian; Xia, Jianyang; Pendall, Elise; Morgan, Jack A; Ryan, Edmund M; Carrillo, Yolima; Dijkstra, Feike A; Zelikova, Tamara J; Norby, Richard J

    2017-09-01

    Multifactor experiments are often advocated as important for advancing terrestrial biosphere models (TBMs), yet to date, such models have only been tested against single-factor experiments. We applied 10 TBMs to the multifactor Prairie Heating and CO 2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were to investigate how multifactor experiments can be used to constrain models and to identify a road map for model improvement. We found models performed poorly in ambient conditions; there was a wide spread in simulated above-ground net primary productivity (range: 31-390 g C m -2  yr -1 ). Comparison with data highlighted model failures particularly with respect to carbon allocation, phenology, and the impact of water stress on phenology. Performance against the observations from single-factors treatments was also relatively poor. In addition, similar responses were predicted for different reasons across models: there were large differences among models in sensitivity to water stress and, among the N cycle models, N availability during the experiment. Models were also unable to capture observed treatment effects on phenology: they overestimated the effect of warming on leaf onset and did not allow CO 2 -induced water savings to extend the growing season length. Observed interactive (CO 2  × warming) treatment effects were subtle and contingent on water stress, phenology, and species composition. As the models did not correctly represent these processes under ambient and single-factor conditions, little extra information was gained by comparing model predictions against interactive responses. We outline a series of key areas in which this and future experiments could be used to improve model predictions of grassland responses to global change. © 2017 John Wiley & Sons Ltd.

  11. Challenging terrestrial biosphere models with data from the long-term multifactor Prairie Heating and CO 2 enrichment experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    De Kauwe, Martin G.; Medlyn, Belinda E.; Walker, Anthony P.

    Multi-factor experiments are often advocated as important for advancing terrestrial biosphere models (TBMs), yet to date such models have only been tested against single-factor experiments. We applied 10 TBMs to the multi-factor Prairie Heating and CO 2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were to investigate how multi-factor experiments can be used to constrain models, and to identify a road map for model improvement. We found models performed poorly in ambient conditions; there was a wide spread in simulated above-ground net primary productivity (range: 31-390 g C m -2 yr -1). Comparison with data highlighted model failures particularlymore » in respect to carbon allocation, phenology, and the impact of water stress on phenology. Performance against single-factors was also relatively poor. In addition, similar responses were predicted for different reasons across models: there were large differences among models in sensitivity to water stress and, among the nitrogen cycle models, nitrogen availability during the experiment. Models were also unable to capture observed treatment effects on phenology: they over-estimated the effect of warming on leaf onset and did not allow CO 2-induced water savings to extend growing season length. Observed interactive (CO 2 x warming) treatment effects were subtle and contingent on water stress, phenology and species composition. Since the models did not correctly represent these processes under ambient and single-factor conditions, little extra information was gained by comparing model predictions against interactive responses. Finally, we outline a series of key areas in which this and future experiments could be used to improve model predictions of grassland responses to global change.« less

  12. Challenging terrestrial biosphere models with data from the long-term multifactor Prairie Heating and CO 2 enrichment experiment

    DOE PAGES

    De Kauwe, Martin G.; Medlyn, Belinda E.; Walker, Anthony P.; ...

    2017-02-01

    Multi-factor experiments are often advocated as important for advancing terrestrial biosphere models (TBMs), yet to date such models have only been tested against single-factor experiments. We applied 10 TBMs to the multi-factor Prairie Heating and CO 2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were to investigate how multi-factor experiments can be used to constrain models, and to identify a road map for model improvement. We found models performed poorly in ambient conditions; there was a wide spread in simulated above-ground net primary productivity (range: 31-390 g C m -2 yr -1). Comparison with data highlighted model failures particularlymore » in respect to carbon allocation, phenology, and the impact of water stress on phenology. Performance against single-factors was also relatively poor. In addition, similar responses were predicted for different reasons across models: there were large differences among models in sensitivity to water stress and, among the nitrogen cycle models, nitrogen availability during the experiment. Models were also unable to capture observed treatment effects on phenology: they over-estimated the effect of warming on leaf onset and did not allow CO 2-induced water savings to extend growing season length. Observed interactive (CO 2 x warming) treatment effects were subtle and contingent on water stress, phenology and species composition. Since the models did not correctly represent these processes under ambient and single-factor conditions, little extra information was gained by comparing model predictions against interactive responses. Finally, we outline a series of key areas in which this and future experiments could be used to improve model predictions of grassland responses to global change.« less

  13. The role of first impression in operant learning.

    PubMed

    Shteingart, Hanan; Neiman, Tal; Loewenstein, Yonatan

    2013-05-01

    We quantified the effect of first experience on behavior in operant learning and studied its underlying computational principles. To that goal, we analyzed more than 200,000 choices in a repeated-choice experiment. We found that the outcome of the first experience has a substantial and lasting effect on participants' subsequent behavior, which we term outcome primacy. We found that this outcome primacy can account for much of the underweighting of rare events, where participants apparently underestimate small probabilities. We modeled behavior in this task using a standard, model-free reinforcement learning algorithm. In this model, the values of the different actions are learned over time and are used to determine the next action according to a predefined action-selection rule. We used a novel nonparametric method to characterize this action-selection rule and showed that the substantial effect of first experience on behavior is consistent with the reinforcement learning model if we assume that the outcome of first experience resets the values of the experienced actions, but not if we assume arbitrary initial conditions. Moreover, the predictive power of our resetting model outperforms previously published models regarding the aggregate choice behavior. These findings suggest that first experience has a disproportionately large effect on subsequent actions, similar to primacy effects in other fields of cognitive psychology. The mechanism of resetting of the initial conditions that underlies outcome primacy may thus also account for other forms of primacy. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  14. Exploring a Comprehensive Model for Early Childhood Vocabulary Instruction: A Design Experiment

    ERIC Educational Resources Information Center

    Wang, X. Christine; Christ, Tanya; Chiu, Ming Ming

    2014-01-01

    Addressing a critical need for effective vocabulary practices in early childhood classrooms, we conducted a design experiment to achieve three goals: (1) developing a comprehensive model for early childhood vocabulary instruction, (2) examining the effectiveness of this model, and (3) discerning the contextual conditions that hinder or facilitate…

  15. How consistent are precipitation patterns predicted by GCMs in the absence of cloud radiative effects?

    NASA Astrophysics Data System (ADS)

    Popke, Dagmar; Bony, Sandrine; Mauritsen, Thorsten; Stevens, Bjorn

    2015-04-01

    Model simulations with state-of-the-art general circulation models reveal a strong disagreement concerning the simulated regional precipitation patterns and their changes with warming. The deviating precipitation response even persists when reducing the model experiment complexity to aquaplanet simulation with forced sea surface temperatures (Stevens and Bony, 2013). To assess feedbacks between clouds and radiation on precipitation responses we analyze data from 5 models performing the aquaplanet simulations of the Clouds On Off Klima Intercomparison Experiment (COOKIE), where the interaction of clouds and radiation is inhibited. Although cloud radiative effects are then disabled, the precipitation patterns among models are as diverse as with cloud radiative effects switched on. Disentangling differing model responses in such simplified experiments thus appears to be key to better understanding the simulated regional precipitation in more standard configurations. By analyzing the local moisture and moist static energy budgets in the COOKIE experiments we investigate likely causes for the disagreement among models. References Stevens, B. & S. Bony: What Are Climate Models Missing?, Science, 2013, 340, 1053-1054

  16. Modelling the effect of shear strength on isentropic compression experiments

    NASA Astrophysics Data System (ADS)

    Thomson, Stuart; Howell, Peter; Ockendon, John; Ockendon, Hilary

    2017-01-01

    Isentropic compression experiments (ICE) are a way of obtaining equation of state information for metals undergoing violent plastic deformation. In a typical experiment, millimetre thick metal samples are subjected to pressures on the order of 10 - 102 GPa, while the yield strength of the material can be as low as 10-2 GPa. The analysis of such experiments has so far neglected the effect of shear strength, instead treating the highly plasticised metal as an inviscid compressible fluid. However making this approximation belies the basic elastic nature of a solid object. A more accurate method should strive to incorporate the small but measurable effects of shear strength. Here we present a one-dimensional mathematical model for elastoplasticity at high stress which allows for both compressibility and the shear strength of the material. In the limit of zero yield stress this model reproduces the hydrodynamic models currently used to analyse ICEs. Numerical solutions of the governing equations will then be presented for problems relevant to ICEs in order to investigate the effects of shear strength compared with a model based purely on hydrodynamics.

  17. Buying and Selling Prices of Investments: Configural Weight Model of Interactions Predicts Violations of Joint Independence.

    PubMed

    Birnbaum; Zimmermann

    1998-05-01

    Judges evaluated buying and selling prices of hypothetical investments, based on the previous price of each investment and estimates of the investment's future value given by advisors of varied expertise. Effect of a source's estimate varied in proportion to the source's expertise, and it varied inversely with the number and expertise of other sources. There was also a configural effect in which the effect of a source's estimate was affected by the rank order of that source's estimate, in relation to other estimates of the same investment. These interactions were fit with a configural weight averaging model in which buyers and sellers place different weights on estimates of different ranks. This model implies that one can design a new experiment in which there will be different violations of joint independence in different viewpoints. Experiment 2 confirmed patterns of violations of joint independence predicted from the model fit in Experiment 1. Experiment 2 also showed that preference reversals between viewpoints can be predicted by the model of Experiment 1. Configural weighting provides a better account of buying and selling prices than either of two models of loss aversion or the theory of anchoring and insufficient adjustment. Copyright 1998 Academic Press.

  18. Study on model design and dynamic similitude relations of vibro-acoustic experiment for elastic cavity

    NASA Astrophysics Data System (ADS)

    Shi, Ao; Lu, Bo; Yang, Dangguo; Wang, Xiansheng; Wu, Junqiang; Zhou, Fangqi

    2018-05-01

    Coupling between aero-acoustic noise and structural vibration under high-speed open cavity flow-induced oscillation may bring about severe random vibration of the structure, and even cause structure to fatigue destruction, which threatens the flight safety. Carrying out the research on vibro-acoustic experiments of scaled down model is an effective means to clarify the effects of high-intensity noise of cavity on structural vibration. Therefore, in allusion to the vibro-acoustic experiments of cavity in wind tunnel, taking typical elastic cavity as the research object, dimensional analysis and finite element method were adopted to establish the similitude relations of structural inherent characteristics and dynamics for distorted model, and verifying the proposed similitude relations by means of experiments and numerical simulation. Research shows that, according to the analysis of scale-down model, the established similitude relations can accurately simulate the structural dynamic characteristics of actual model, which provides theoretic guidance for structural design and vibro-acoustic experiments of scaled down elastic cavity model.

  19. Quantifying second generation ethanol inhibition: Design of Experiments approach and kinetic model development.

    PubMed

    Schneiderman, Steven J; Johnson, Roger W; Menkhaus, Todd J; Gilcrease, Patrick C

    2015-03-01

    While softwoods represent a potential feedstock for second generation ethanol production, compounds present in their hydrolysates can inhibit fermentation. In this study, a novel Design of Experiments (DoE) approach was used to identify significant inhibitory effects on Saccharomyces cerevisiae D5A for the purpose of guiding kinetic model development. Although acetic acid, furfural and 5-hydroxymethyl furfural (HMF) were present at potentially inhibitory levels, initial factorial experiments only identified ethanol as a significant rate inhibitor. It was hypothesized that high ethanol levels masked the effects of other inhibitors, and a subsequent factorial design without ethanol found significant effects for all other compounds. When these non-ethanol effects were accounted for in the kinetic model, R¯(2) was significantly improved over an ethanol-inhibition only model (R¯(2)=0.80 vs. 0.76). In conclusion, when ethanol masking effects are removed, DoE is a valuable tool to identify significant non-ethanol inhibitors and guide kinetic model development. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Shopper marketing: a new challenge for Spanish community pharmacies.

    PubMed

    Gavilan, Diana; Avello, Maria; Abril, Carmen

    2014-01-01

    Changes that have occurred over the past few decades in retailing and in the health care sector--namely, a drastic reduction in drug profit-margins, and a more critical use of health services by patients--have created a scenario characterized by rising competitiveness. This new context is necessitating community pharmacies (hereafter, pharmacies) to improve their business model through new strategies. Shopper marketing has proven invaluable in other retail settings and therefore, could be a critical element for new practices in pharmacies. First, to analyze how shopping experiences in pharmacies based on new practices in shopper marketing affect shopping behavior. Second, to study the mediating effect of customer satisfaction on the relationship between shopping experiences and shopping behavior. A self-reported questionnaire was developed to measure four concepts: hedonic experience (enjoyable), functional experience (goal-oriented), customer satisfaction and shopping behavior. Data were collected from 28 different pharmacies dispersed throughout Spain. Structural equation modeling (SEM) was used to test the relationships in the theoretical model. First, the measurement model was estimated to assess model fit, reliability, convergent and discriminant validity. Then, the parameters of the structural model were estimated and the mediation effects were subsequently tested. Functional experience and hedonic experience each significantly and positively correlate with consumer satisfaction and with customer shopping behavior (purchases and loyalty). Moreover, the effects of each type of experience on shopping behavior are partially mediated by customer satisfaction. The results suggest that even in Spanish pharmacies, which have traditionally been considered as strictly functional retailers, ensuring customer satisfaction and enhancing shopping behavior now demand more than just functional experiences. Moreover, a customer's experience at a pharmacy can itself trigger a shopping cycle; therefore, pharmacists should consider prioritizing investments in hedonic experiences. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Simulating the effects of fluctuating dissolved oxygen on growth, reproduction, and survival of fish and shrimp.

    PubMed

    Miller Neilan, Rachael; Rose, Kenneth

    2014-02-21

    Individuals are commonly exposed to fluctuating levels of stressors, while most laboratory experiments focus on constant exposures. We develop and test a mathematical model for predicting the effects of low dissolved oxygen (hypoxia) on growth, reproduction, and survival using laboratory experiments on fish and shrimp. The exposure-effects model simulates the hourly reductions in growth and survival, and the reduction in reproduction (fecundity) at times of spawning, of an individual as it is exposed to constant or hourly fluctuating dissolved oxygen (DO) concentrations. The model was applied to seven experiments involving fish and shrimp that included constant and fluctuating DO exposures, with constant exposures used for parameter estimation and the model then used to simulate the growth, reproduction, and survival in the fluctuating treatments. Cumulative effects on growth, reproduction, and survival were predicted well by the model, but the model did not replay the observed episodic low survival days. Further investigation should involve the role of acclimation, possible inclusion of repair effects in reproduction and survival, and the sensitivity of model predictions to the shape of the immediate effects function. Additional testing of the model with other taxa, different patterns of fluctuating exposures, and different stressors is needed to determine the model's generality and robustness. © 2013 Elsevier Ltd. All rights reserved.

  2. Mentally walking through doorways causes forgetting: The location updating effect and imagination.

    PubMed

    Lawrence, Zachary; Peterson, Daniel

    2016-01-01

    Researchers have documented an intriguing phenomenon whereby simply walking through a doorway causes forgetting (the location updating effect). The Event Horizon Model is the most commonly cited theory to explain these data. Importantly, this model explains the effect without invoking the importance or reliance upon perceptual information (i.e., seeing oneself pass through the doorway). This generates the intriguing hypothesis that the effect may be demonstrated in participants who simply imagine walking through a doorway. Across two experiments, we explicitly test this hypothesis. Participants familiarised themselves with both real (Experiment 1) and virtual (Experiment 2) environments which served as the setting for their mental walk. They were then provided with an image to remember and were instructed to imagine themselves walking through the previously presented space. In both experiments, when the mental walk required participants to pass through a doorway, more forgetting occurred, consistent with the predictions laid out in the Event Horizon Model.

  3. Evaluation of an imputed pitch velocity model of the auditory kappa effect.

    PubMed

    Henry, Molly J; McAuley, J Devin

    2009-04-01

    Three experiments evaluated an imputed pitch velocity model of the auditory kappa effect. Listeners heard 3-tone sequences and judged the timing of the middle (target) tone relative to the timing of the 1st and 3rd (bounding) tones. Experiment 1 held pitch constant but varied the time (T) interval between bounding tones (T = 728, 1,000, or 1,600 ms) in order to establish baseline performance levels for the 3 values of T. Experiments 2 and 3 combined the values of T tested in Experiment 1 with a pitch manipulation in order to create fast (8 semitones/728 ms), medium (8 semitones/1,000 ms), and slow (8 semitones/1,600 ms) velocity conditions. Consistent with an auditory motion hypothesis, distortions in perceived timing were larger for fast than for slow velocity conditions for both ascending sequences (Experiment 2) and descending sequences (Experiment 3). Overall, results supported the proposed imputed pitch velocity model of the auditory kappa effect. (c) 2009 APA, all rights reserved.

  4. Amazon rainforest responses to elevated CO2: Deriving model-based hypotheses for the AmazonFACE experiment

    NASA Astrophysics Data System (ADS)

    Rammig, A.; Fleischer, K.; Lapola, D.; Holm, J.; Hoosbeek, M.

    2017-12-01

    Increasing atmospheric CO2 concentration is assumed to have a stimulating effect ("CO2 fertilization effect") on forest growth and resilience. Empirical evidence, however, for the existence and strength of such a tropical CO2 fertilization effect is scarce and thus a major impediment for constraining the uncertainties in Earth System Model projections. The implications of the tropical CO2 effect are far-reaching, as it strongly influences the global carbon and water cycle, and hence future global climate. In the scope of the Amazon Free Air CO2 Enrichment (FACE) experiment, we addressed these uncertainties by assessing the CO2 fertilization effect at ecosystem scale. AmazonFACE is the first FACE experiment in an old-growth, highly diverse tropical rainforest. Here, we present a priori model-based hypotheses for the experiment derived from a set of 12 ecosystem models. Model simulations identified key uncertainties in our understanding of limiting processes and derived model-based hypotheses of expected ecosystem responses to elevated CO2 that can directly be tested during the experiment. Ambient model simulations compared satisfactorily with in-situ measurements of ecosystem carbon fluxes, as well as carbon, nitrogen, and phosphorus stocks. Models consistently predicted an increase in photosynthesis with elevated CO2, which declined over time due to developing limitations. The conversion of enhanced photosynthesis into biomass, and hence ecosystem carbon sequestration, varied strongly among the models due to different assumptions on nutrient limitation. Models with flexible allocation schemes consistently predicted an increased investment in belowground structures to alleviate nutrient limitation, in turn accelerating turnover rates of soil organic matter. The models diverged on the prediction for carbon accumulation after 10 years of elevated CO2, mainly due to contrasting assumptions in their phosphorus cycle representation. These differences define the expected response ratio to elevated CO2 at the AmazonFACE site and identify priorities for experimental work and model development.

  5. Lack of blinding of outcome assessors in animal model experiments implies risk of observer bias.

    PubMed

    Bello, Segun; Krogsbøll, Lasse T; Gruber, Jan; Zhao, Zhizhuang J; Fischer, Doris; Hróbjartsson, Asbjørn

    2014-09-01

    To examine the impact of not blinding outcome assessors on estimates of intervention effects in animal experiments modeling human clinical conditions. We searched PubMed, Biosis, Google Scholar, and HighWire Press and included animal model experiments with both blinded and nonblinded outcome assessors. For each experiment, we calculated the ratio of odds ratios (ROR), that is, the odds ratio (OR) from nonblinded assessments relative to the corresponding OR from blinded assessments. We standardized the ORs according to the experimental hypothesis, such that an ROR <1 indicates that nonblinded assessor exaggerated intervention effect, that is, exaggerated benefit in experiments investigating possible benefit or exaggerated harm in experiments investigating possible harm. We pooled RORs with inverse variance random-effects meta-analysis. We included 10 (2,450 animals) experiments in the main meta-analysis. Outcomes were subjective in most experiments. The pooled ROR was 0.41 (95% confidence interval [CI], 0.20, 0.82; I(2) = 75%; P < 0.001), indicating an average exaggeration of the nonblinded ORs by 59%. The heterogeneity was quantitative and caused by three pesticides experiments with very large observer bias, pooled ROR was 0.20 (95% CI, 0.07, 0.59) in contrast to the pooled ROR in the other seven experiments, 0.82 (95% CI, 0.57, 1.17). Lack of blinding of outcome assessors in animal model experiments with subjective outcomes implies a considerable risk of observer bias. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Modeling the Effects of Argument Length and Validity on Inductive and Deductive Reasoning

    ERIC Educational Resources Information Center

    Rotello, Caren M.; Heit, Evan

    2009-01-01

    In an effort to assess models of inductive reasoning and deductive reasoning, the authors, in 3 experiments, examined the effects of argument length and logical validity on evaluation of arguments. In Experiments 1a and 1b, participants were given either induction or deduction instructions for a common set of stimuli. Two distinct effects were…

  7. Anatomical Knowledge Gain through a Clay-Modeling Exercise Compared to Live and Video Observations

    ERIC Educational Resources Information Center

    Kooloos, Jan G. M.; Schepens-Franke, Annelieke N.; Bergman, Esther M.; Donders, Rogier A. R. T.; Vorstenbosch, Marc A. T. M.

    2014-01-01

    Clay modeling is increasingly used as a teaching method other than dissection. The haptic experience during clay modeling is supposed to correspond to the learning effect of manipulations during exercises in the dissection room involving tissues and organs. We questioned this assumption in two pretest-post-test experiments. In these experiments,…

  8. The Mechanisms of Psychedelic Visionary Experiences: Hypotheses from Evolutionary Psychology

    PubMed Central

    Winkelman, Michael J.

    2017-01-01

    Neuropharmacological effects of psychedelics have profound cognitive, emotional, and social effects that inspired the development of cultures and religions worldwide. Findings that psychedelics objectively and reliably produce mystical experiences press the question of the neuropharmacological mechanisms by which these highly significant experiences are produced by exogenous neurotransmitter analogs. Humans have a long evolutionary relationship with psychedelics, a consequence of psychedelics' selective effects for human cognitive abilities, exemplified in the information rich visionary experiences. Objective evidence that psychedelics produce classic mystical experiences, coupled with the finding that hallucinatory experiences can be induced by many non-drug mechanisms, illustrates the need for a common model of visionary effects. Several models implicate disturbances of normal regulatory processes in the brain as the underlying mechanisms responsible for the similarities of visionary experiences produced by psychedelic and other methods for altering consciousness. Similarities in psychedelic-induced visionary experiences and those produced by practices such as meditation and hypnosis and pathological conditions such as epilepsy indicate the need for a general model explaining visionary experiences. Common mechanisms underlying diverse alterations of consciousness involve the disruption of normal functions of the prefrontal cortex and default mode network (DMN). This interruption of ordinary control mechanisms allows for the release of thalamic and other lower brain discharges that stimulate a visual information representation system and release the effects of innate cognitive functions and operators. Converging forms of evidence support the hypothesis that the source of psychedelic experiences involves the emergence of these innate cognitive processes of lower brain systems, with visionary experiences resulting from the activation of innate processes based in the mirror neuron system (MNS). PMID:29033783

  9. A three-dimensional finite element model of near-field scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    Balusek, Curtis; Friedman, Barry; Luna, Darwin; Oetiker, Brian; Babajanyan, Arsen; Lee, Kiejin

    2012-10-01

    A three-dimensional finite element model of an experimental near-field scanning microwave microscope (NSMM) has been developed and compared to experiment on non conducting samples. The microwave reflection coefficient S11 is calculated as a function of frequency with no adjustable parameters. There is qualitative agreement with experiment in that the resonant frequency can show a sizable increase with sample dielectric constant; a result that is not obtained with a two-dimensional model. The most realistic model shows a semi-quantitative agreement with experiment. The effect of different sample thicknesses and varying tip sample distances is investigated numerically and shown to effect NSMM performance in a way consistent with experiment. Visualization of the electric field indicates that the field is primarily determined by the shape of the coupling hooks.

  10. Modelling audiovisual integration of affect from videos and music.

    PubMed

    Gao, Chuanji; Wedell, Douglas H; Kim, Jongwan; Weber, Christine E; Shinkareva, Svetlana V

    2018-05-01

    Two experiments examined how affective values from visual and auditory modalities are integrated. Experiment 1 paired music and videos drawn from three levels of valence while holding arousal constant. Experiment 2 included a parallel combination of three levels of arousal while holding valence constant. In each experiment, participants rated their affective states after unimodal and multimodal presentations. Experiment 1 revealed a congruency effect in which stimulus combinations of the same extreme valence resulted in more extreme state ratings than component stimuli presented in isolation. An interaction between music and video valence reflected the greater influence of negative affect. Video valence was found to have a significantly greater effect on combined ratings than music valence. The pattern of data was explained by a five parameter differential weight averaging model that attributed greater weight to the visual modality and increased weight with decreasing values of valence. Experiment 2 revealed a congruency effect only for high arousal combinations and no interaction effects. This pattern was explained by a three parameter constant weight averaging model with greater weight for the auditory modality and a very low arousal value for the initial state. These results demonstrate key differences in audiovisual integration between valence and arousal.

  11. Use of animal models for space flight physiology studies, with special focus on the immune system

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, Gerald

    2005-01-01

    Animal models have been used to study the effects of space flight on physiological systems. The animal models have been used because of the limited availability of human subjects for studies to be carried out in space as well as because of the need to carry out experiments requiring samples and experimental conditions that cannot be performed using humans. Experiments have been carried out in space using a variety of species, and included developmental biology studies. These species included rats, mice, non-human primates, fish, invertebrates, amphibians and insects. The species were chosen because they best fit the experimental conditions required for the experiments. Experiments with animals have also been carried out utilizing ground-based models that simulate some of the effects of exposure to space flight conditions. Most of the animal studies have generated results that parallel the effects of space flight on human physiological systems. Systems studied have included the neurovestibular system, the musculoskeletal system, the immune system, the neurological system, the hematological system, and the cardiovascular system. Hindlimb unloading, a ground-based model of some of the effects of space flight on the immune system, has been used to study the effects of space flight conditions on physiological parameters. For the immune system, exposure to hindlimb unloading has been shown to results in alterations of the immune system similar to those observed after space flight. This has permitted the development of experiments that demonstrated compromised resistance to infection in rodents maintained in the hindlimb unloading model as well as the beginning of studies to develop countermeasures to ameliorate or prevent such occurrences. Although there are limitations to the use of animal models for the effects of space flight on physiological systems, the animal models should prove very valuable in designing countermeasures for exploration class missions of the future.

  12. Effects of vitamin K2 (menatetrenone) and alendronate on bone mineral density and bone strength in rats fed a low-magnesium diet.

    PubMed

    Kobayashi, M; Hara, K; Akiyama, Y

    2004-11-01

    In this study, we examined changes in bone parameters and bone strength in rats fed low-Mg diets (experiment 1) and the effects of vitamin K2 (MK-4, experiment 3) and alendronate (ALN, experiment 2) in this model. In experiment 1, 5-week-old male Wistar rats were fed three low-Mg diets (Mg 9, 6, 3 mg/100 g diet) for 4 weeks. Although the cortical bone mineral content (CtBMC) and cortical thickness (CtTh) of the femoral diaphysis in all low-Mg-diet groups were the same as or greater than those in the intact group (Mg: 90 mg/100 g diet), the maximum load and elastic modulus were significantly reduced in the 3-mg-Mg group. In experiment 2, 4-week-old Wistar rats were fed a 6-mg-Mg diet for 8 weeks, and the effect of ALN (2, 20, and 200 microg/kg twice a week) was evaluated. The administration of ALN at 200 microg/kg increased the cortical bone mineral content (CtBMC), CtTh, and maximum load, but had no effect on the elastic modulus, as compared with the low-Mg-control group. In experiment 3, the effect of MK-4 was evaluated under the same conditions as in experiment 2. The administration of MK-4 had no effect on CtBMC, CtTh, or bone components of the femoral diaphysis. However, MK-4 inhibited the decreases in maximum load and elastic modulus due to the low-Mg diet. Since there is no other experimental model in which there is a decrease in bone mechanical properties without a decrease in bone mineral content, the low-Mg diet model is considered to be an excellent model for examining bone quality. Our results from this model suggest that MK-4 and ALN affect bone mechanical properties by different mechanisms.

  13. Experiences with a high-blockage model tested in the NASA Ames 12-foot pressure wind tunnel

    NASA Technical Reports Server (NTRS)

    Coder, D. W.

    1984-01-01

    Representation of the flow around full-scale ships was sought in the subsonic wind tunnels in order to a Hain Reynolds numbers as high as possible. As part of the quest to attain the largest possible Reynolds number, large models with high blockage are used which result in significant wall interference effects. Some experiences with such a high blockage model tested in the NASA Ames 12-foot pressure wind tunnel are summarized. The main results of the experiment relating to wind tunnel wall interference effects are also presented.

  14. DEM Particle Fracture Model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Boning; Herbold, Eric B.; Homel, Michael A.

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density andmore » packings o the samples are also studied in numerical examples.« less

  15. Risk-Based Fire Safety Experiment Definition for Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Apostolakis, G. E.; Ho, V. S.; Marcus, E.; Perry, A. T.; Thompson, S. L.

    1989-01-01

    Risk methodology is used to define experiments to be conducted in space which will help to construct and test the models required for accident sequence identification. The development of accident scenarios is based on the realization that whether damage occurs depends on the time competition of two processes: the ignition and creation of an adverse environment, and the detection and suppression activities. If the fire grows and causes damage faster than it is detected and suppressed, then an accident occurred. The proposed integrated experiments will provide information on individual models that apply to each of the above processes, as well as previously unidentified interactions and processes, if any. Initially, models that are used in terrestrial fire risk assessments are considered. These include heat and smoke release models, detection and suppression models, as well as damage models. In cases where the absence of gravity substantially invalidates a model, alternate models will be developed. Models that depend on buoyancy effects, such as the multizone compartment fire models, are included in these cases. The experiments will be performed in a variety of geometries simulating habitable areas, racks, and other spaces. These simulations will necessitate theoretical studies of scaling effects. Sensitivity studies will also be carried out including the effects of varying oxygen concentrations, pressures, fuel orientation and geometry, and air flow rates. The experimental apparatus described herein includes three major modules: the combustion, the fluids, and the command and power modules.

  16. Uncertainties in SOA Formation from the Photooxidation of α-pinene

    NASA Astrophysics Data System (ADS)

    McVay, R.; Zhang, X.; Aumont, B.; Valorso, R.; Camredon, M.; La, S.; Seinfeld, J.

    2015-12-01

    Explicit chemical models such as GECKO-A (the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) enable detailed modeling of gas-phase photooxidation and secondary organic aerosol (SOA) formation. Comparison between these explicit models and chamber experiments can provide insight into processes that are missing or unknown in these models. GECKO-A is used to model seven SOA formation experiments from α-pinene photooxidation conducted at varying seed particle concentrations with varying oxidation rates. We investigate various physical and chemical processes to evaluate the extent of agreement between the experiments and the model predictions. We examine the effect of vapor wall loss on SOA formation and how the importance of this effect changes at different oxidation rates. Proposed gas-phase autoxidation mechanisms are shown to significantly affect SOA predictions. The potential effects of particle-phase dimerization and condensed-phase photolysis are investigated. We demonstrate the extent to which SOA predictions in the α-pinene photooxidation system depend on uncertainties in the chemical mechanism.

  17. Active machine learning-driven experimentation to determine compound effects on protein patterns.

    PubMed

    Naik, Armaghan W; Kangas, Joshua D; Sullivan, Devin P; Murphy, Robert F

    2016-02-03

    High throughput screening determines the effects of many conditions on a given biological target. Currently, to estimate the effects of those conditions on other targets requires either strong modeling assumptions (e.g. similarities among targets) or separate screens. Ideally, data-driven experimentation could be used to learn accurate models for many conditions and targets without doing all possible experiments. We have previously described an active machine learning algorithm that can iteratively choose small sets of experiments to learn models of multiple effects. We now show that, with no prior knowledge and with liquid handling robotics and automated microscopy under its control, this learner accurately learned the effects of 48 chemical compounds on the subcellular localization of 48 proteins while performing only 29% of all possible experiments. The results represent the first practical demonstration of the utility of active learning-driven biological experimentation in which the set of possible phenotypes is unknown in advance.

  18. Modeling and experiments on tritium permeation in fusion reactor blankets

    NASA Astrophysics Data System (ADS)

    Holland, D. F.; Longhurst, G. R.

    The determination of tritium loss from helium-cooled fusion breeding blankets are discussed. The issues are: (1) applicability of present models to permeation at low tritium pressures; (2) effectiveness of oxide layers in reducing permeation; (3) effectiveness of hydrogen addition as a means to lower tritium permeation; and (4) effectiveness of conversion to tritiated water and subsequent trapping to reduce permeation. Theoretical models applicable to these issues are discussed, and results of experiments in two areas are presented; permeation of mixtures of hydrogen isotopes and conversion to tritiated water.

  19. Statistical inference of empirical constituents in partitioned analysis from integral-effect experiments: An application in thermo-mechanical coupling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stevens, Garrison N.; Atamturktur, Sez; Brown, D. Andrew

    Rapid advancements in parallel computing over the last two decades have enabled simulations of complex, coupled systems through partitioning. In partitioned analysis, independently developed constituent models communicate, representing dependencies between multiple physical phenomena that occur in the full system. Figure 1 schematically demonstrates a coupled system with two constituent models, each resolving different physical behavior. In this figure, the constituent model, denoted as the “consumer,” relies upon some input parameter that is being provided by the constituent model acting as a “feeder”. The role of the feeder model is to map operating conditions (i.e. those that are stimulating the process)more » to consumer inputs, thus providing functional inputs to the consumer model*. Problems arise if the feeder model cannot be built–a challenge that is prevalent for highly complex systems in extreme operational conditions that push the limits of our understanding of underlying physical behavior. Often, these are also the situations where separate-effect experiments isolating the physical phenomena are not available; meaning that experimentally determining the unknown constituent behavior is not possible (Bauer and Holland, 1995; Unal et al., 2013), and that integral-effect experiments that reflect the behavior of the complete system tend to be the only available observations. In this paper, the authors advocate for the usefulness of integral-effect experiments in furthering a model developer’s knowledge of the physics principles governing the system behavior of interest.« less

  20. Statistical inference of empirical constituents in partitioned analysis from integral-effect experiments: An application in thermo-mechanical coupling

    DOE PAGES

    Stevens, Garrison N.; Atamturktur, Sez; Brown, D. Andrew; ...

    2018-04-16

    Rapid advancements in parallel computing over the last two decades have enabled simulations of complex, coupled systems through partitioning. In partitioned analysis, independently developed constituent models communicate, representing dependencies between multiple physical phenomena that occur in the full system. Figure 1 schematically demonstrates a coupled system with two constituent models, each resolving different physical behavior. In this figure, the constituent model, denoted as the “consumer,” relies upon some input parameter that is being provided by the constituent model acting as a “feeder”. The role of the feeder model is to map operating conditions (i.e. those that are stimulating the process)more » to consumer inputs, thus providing functional inputs to the consumer model*. Problems arise if the feeder model cannot be built–a challenge that is prevalent for highly complex systems in extreme operational conditions that push the limits of our understanding of underlying physical behavior. Often, these are also the situations where separate-effect experiments isolating the physical phenomena are not available; meaning that experimentally determining the unknown constituent behavior is not possible (Bauer and Holland, 1995; Unal et al., 2013), and that integral-effect experiments that reflect the behavior of the complete system tend to be the only available observations. In this paper, the authors advocate for the usefulness of integral-effect experiments in furthering a model developer’s knowledge of the physics principles governing the system behavior of interest.« less

  1. Effects of response-independent stimuli on fixed-interval and fixed-ratio performance of rats: a model for stressful disruption of cyclical eating patterns.

    PubMed

    Reed, Phil

    2011-03-01

    Binge eating is often associated with stress-induced disruption of typical eating patterns. Three experiments were performed with the aim of developing a potential model for this effect by investigating the effect of presenting response-independent stimuli on rats' lever-pressing for food reinforcement during both fixed-interval (FI) and fixed-ratio (FR) schedules of reinforcement. In Experiment 1, a response-independent brief tone (500-ms, 105-dB, broadband, noisy signal, ranging up to 16 kHz, with spectral peaks at 3 and 500 Hz) disrupted the performance on an FI 60-s schedule. Responding with the response-independent tone was more vigorous than in the absence of the tone. This effect was replicated in Experiment 2 using a within-subject design, but no such effect was noted when a light was employed as a disrupter. In Experiment 3, a 500-ms tone, but not a light, had a similar effect on rats' performance on FR schedules. This tone-induced effect may represent a release from response-inhibition produced by an aversive event. The implications of these results for modeling binge eating are discussed.

  2. An effective hierarchical model for the biomolecular covalent bond: an approach integrating artificial chemistry and an actual terrestrial life system.

    PubMed

    Oohashi, Tsutomu; Ueno, Osamu; Maekawa, Tadao; Kawai, Norie; Nishina, Emi; Honda, Manabu

    2009-01-01

    Under the AChem paradigm and the programmed self-decomposition (PSD) model, we propose a hierarchical model for the biomolecular covalent bond (HBCB model). This model assumes that terrestrial organisms arrange their biomolecules in a hierarchical structure according to the energy strength of their covalent bonds. It also assumes that they have evolutionarily selected the PSD mechanism of turning biological polymers (BPs) into biological monomers (BMs) as an efficient biomolecular recycling strategy We have examined the validity and effectiveness of the HBCB model by coordinating two complementary approaches: biological experiments using existent terrestrial life, and simulation experiments using an AChem system. Biological experiments have shown that terrestrial life possesses a PSD mechanism as an endergonic, genetically regulated process and that hydrolysis, which decomposes a BP into BMs, is one of the main processes of such a mechanism. In simulation experiments, we compared different virtual self-decomposition processes. The virtual species in which the self-decomposition process mainly involved covalent bond cleavage from a BP to BMs showed evolutionary superiority over other species in which the self-decomposition process involved cleavage from BP to classes lower than BM. These converging findings strongly support the existence of PSD and the validity and effectiveness of the HBCB model.

  3. Modeling of grain size strengthening in tantalum at high pressures and strain rates

    DOE PAGES

    Rudd, Robert E.; Park, H. -S.; Cavallo, R. M.; ...

    2017-01-01

    Laser-driven ramp wave compression experiments have been used to investigate the strength (flow stress) of tantalum and other metals at high pressures and high strain rates. Recently this kind of experiment has been used to assess the dependence of the strength on the average grain size of the material, finding no detectable variation with grain size. The insensitivity to grain size has been understood theoretically to result from the dominant effect of the high dislocation density generated at the extremely high strain rates of the experiment. Here we review the experiments and describe in detail the multiscale strength model usedmore » to simulate them. The multiscale strength model has been extended to include the effect of geometrically necessary dislocations generated at the grain boundaries during compatible plastic flow in the polycrystalline metal. Lastly, we use the extended model to make predictions of the threshold strain rates and grain sizes below which grain size strengthening would be observed in the laser-driven Rayleigh-Taylor experiments.« less

  4. The effects of corona on current surges induced on conducting lines by EMP: A comparison of experiment data with results of analytic corona models

    NASA Astrophysics Data System (ADS)

    Blanchard, J. P.; Tesche, F. M.; McConnell, B. W.

    1987-09-01

    An experiment to determine the interaction of an intense electromagnetic pulse (EMP), such as that produced by a nuclear detonation above the Earth's atmosphere, was performed in March, 1986 at Kirtland Air Force Base near Albuquerque, New Mexico. The results of that experiment have been published without analysis. Following an introduction of the corona phenomenon, the reason for interest in it, and a review of the experiment, this paper discusses five different analytic corona models that may model corona formation on a conducting line subjected to EMP. The results predicted by these models are compared with measured data acquired during the experiment to determine the strengths and weaknesses of each model.

  5. The Impact of Sexual Orientation on Women's Midlife Experience: A Transition Model Approach

    ERIC Educational Resources Information Center

    Boyer, Carol Anderson

    2007-01-01

    Sexual orientation is an integral part of identity affecting every stage of an individual's development. This literature review examines women's cultural experiences based on sexual orientation and their effect on midlife experience. A developmental model is offered that incorporates sexual orientation as a contextual factor in this developmental…

  6. Modelling and Simulation as a Recognizing Method in Education

    ERIC Educational Resources Information Center

    Stoffa, Veronika

    2004-01-01

    Computer animation-simulation models of complex processes and events, which are the method of instruction, can be an effective didactic device. Gaining deeper knowledge about objects modelled helps to plan simulation experiments oriented on processes and events researched. Animation experiments realized on multimedia computers can aid easier…

  7. A Classroom-Field Model of Inter-Ethnic Communication.

    ERIC Educational Resources Information Center

    Nielsen, Keith E.

    The BLBC (bilingual-bicultural) model of inter-ethnic communication is an effective method for bridging the instructional "gap" between classroom education and field experiences. These two learning experiences are distinct; yet each should complement the other. The BLBC model of inter-ethnic communication attempts to interface the student's…

  8. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2008-09-01

    QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. The model uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  9. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2009-02-01

    QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. The model uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  10. CFD Modeling of the Multipurpose Hydrogen Test Bed (MHTB) Self-Pressurization and Spray Bar Mixing Experiments in Normal Gravity: Effect of Accommodation Coefficient on the Tank Pressure

    NASA Technical Reports Server (NTRS)

    Kartuzova, Olga; Kassemi, Mohammad

    2015-01-01

    In this paper, a computational model that describes pressure control phase of a typical MHTB experiment will be presented. The fidelity of the model will be assessed by comparing the models predictions with MHTB experimental data. In this paper CFD results for MHTB spray bar cooling case with 50 tank fill ratio will be presented and analyzed. Effect of accommodation coefficient for calculating droplet-ullage mass transfer will be evaluated.

  11. The effects of quantity and depth of processing on children's time perception.

    PubMed

    Arlin, M

    1986-08-01

    Two experiments were conducted to investigate the effects of quantity and depth of processing on children's time perception. These experiments tested the appropriateness of two adult time-perception models (attentional and storage size) for younger ages. Children were given stimulus sets of equal time which varied by level of processing (deep/shallow) and quantity (list length). In the first experiment, 28 children in Grade 6 reproduced presentation times of various quantities of pictures under deep (living/nonliving categorization) or shallow (repeating label) conditions. Students also compared pairs of durations. In the second experiment, 128 children in Grades K, 2, 4, and 6 reproduced presentation times under similar conditions with three or six pictures and with deep or shallow processing requirements. Deep processing led to decreased estimation of time. Higher quantity led to increased estimation of time. Comparative judgments were influenced by quantity. The interaction between age and depth of processing was significant. Older children were more affected by depth differences than were younger children. Results were interpreted as supporting different aspects of each adult model as explanations of children's time perception. The processing effect supported the attentional model and the quantity effect supported the storage size model.

  12. The effect of shear strength on isentropic compression experiments

    NASA Astrophysics Data System (ADS)

    Thomson, Stuart; Howell, Peter; Ockendon, John; Ockendon, Hilary

    2015-06-01

    Isentropic compression experiments (ICE) are a novel way of obtaining equation of state information for metals undergoing violent plastic deformation. In a typical experiment, millimetre thick metal samples are subjected to pressures on the order of 10 -102 GPa, while the yield strength of the material can be as low as 10-1GPa. The analysis of such experiments has so far neglected the effect of shear strength, instead treating the highly plasticised metal as an inviscid compressible fluid. However making this approximation belies the basic elastic nature of a solid object. A more accurate method should strive to incorporate the small but measurable effects of shear strength. Here we present a one-dimensional mathematical model for elastoplasticity at high stress which allows for both compressibility and the shear strength of the material. In the limit of zero yield stress this model reproduces the hydrodynamic models currently used to analyse ICEs. We will also show using a systematic asymptotic analysis that entropy changes are universally negligible in the absence of shocks. Numerical solutions of the governing equations will then be presented for problems relevant to ICEs in order to investigate the effects of shear strength over a model based purely on hydrodynamics.

  13. Two ecological models of academic achievement among diverse students with and without disabilities in transition.

    PubMed

    Williams, Terrinieka T; McMahon, Susan D; Keys, Christopher B

    2014-01-01

    School experiences can have positive effects on student academic achievement, yet less is known about intermediary processes that contribute to these positive effects. We examined pathways between school experiences and academic achievement among 117 low-income urban students of color, many with disabilities, who transitioned to other schools following a school closure. Using structural equation modeling, we tested two ecological models that examined the relationships among self-reported school experiences, school support, academic self-efficacy, and school-reported academic achievement. The model in which the relationship between school experiences and academic achievement is mediated by both school support and academic self-efficacy, and that takes previous academic achievement into account, was an excellent fit with the data. The roles of contextual and individual factors as they relate to academic achievement, and the implications of these findings, are discussed.

  14. Generative Modeling for Machine Learning on the D-Wave

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Thulasidasan, Sunil

    These are slides on Generative Modeling for Machine Learning on the D-Wave. The following topics are detailed: generative models; Boltzmann machines: a generative model; restricted Boltzmann machines; learning parameters: RBM training; practical ways to train RBM; D-Wave as a Boltzmann sampler; mapping RBM onto the D-Wave; Chimera restricted RBM; mapping binary RBM to Ising model; experiments; data; D-Wave effective temperature, parameters noise, etc.; experiments: contrastive divergence (CD) 1 step; after 50 steps of CD; after 100 steps of CD; D-Wave (experiments 1, 2, 3); D-Wave observations.

  15. QUAGMIRE v1.3: a quasi-geostrophic model for investigating rotating fluids experiments

    NASA Astrophysics Data System (ADS)

    Williams, P. D.; Haine, T. W. N.; Read, P. L.; Lewis, S. R.; Yamazaki, Y. H.

    2009-04-01

    The QUAGMIRE model has recently been made freely available for public use. QUAGMIRE is a quasi-geostrophic numerical model for performing fast, high-resolution simulations of multi-layer rotating annulus laboratory experiments on a desktop personal computer. This presentation describes the model's main features. QUAGMIRE uses a hybrid finite-difference/spectral approach to numerically integrate the coupled nonlinear partial differential equations of motion in cylindrical geometry in each layer. Version 1.3 implements the special case of two fluid layers of equal resting depths. The flow is forced either by a differentially rotating lid, or by relaxation to specified streamfunction or potential vorticity fields, or both. Dissipation is achieved through Ekman layer pumping and suction at the horizontal boundaries, including the internal interface. The effects of weak interfacial tension are included, as well as the linear topographic beta-effect and the quadratic centripetal beta-effect. Stochastic forcing may optionally be activated, to represent approximately the effects of random unresolved features. A leapfrog time stepping scheme is used, with a Robert filter. Flows simulated by the model agree well with those observed in the corresponding laboratory experiments.

  16. Investigating strength and frequency effects in recognition memory using type-2 signal detection theory.

    PubMed

    Higham, Philip A; Perfect, Timothy J; Bruno, Davide

    2009-01-01

    Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower false alarm rate, for low frequency words compared with high frequency words. In Experiment 2, the authors manipulated item strength with repetition, which showed an increased hit rate but no effect on the false alarm rate. Whereas Type-1 indices were ambiguous as to whether these effects were based on a criterion- or distribution-shift model, the two models predict opposite effects on Type-2 distractor monitoring under some assumptions. Hence, Type-2 ROC analysis discriminated between potential models of recognition that could not be discriminated using Type-1 indices alone. In Experiment 3, the authors manipulated Type-1 response bias by varying the number of old versus new response categories to confirm the assumptions made in Experiments 1 and 2. The authors conclude that Type-2 analyses are a useful tool for investigating recognition memory when used in conjunction with more traditional Type-1 analyses.

  17. Work Experience, Socialization, and Civil Liberties

    ERIC Educational Resources Information Center

    Korman, Abraham K.

    1975-01-01

    Examines the effects of work experience on attitudes and behaviors in the area of civil liberties; (1) noting that hierarchical structure, rigidity and specialization seem to generate negative effect toward civil libertarian concerns, and (2) proposing a theoretical model designed to predict the conditions under which work experience may be…

  18. Modeling the effects of argument length and validity on inductive and deductive reasoning.

    PubMed

    Rotello, Caren M; Heit, Evan

    2009-09-01

    In an effort to assess models of inductive reasoning and deductive reasoning, the authors, in 3 experiments, examined the effects of argument length and logical validity on evaluation of arguments. In Experiments 1a and 1b, participants were given either induction or deduction instructions for a common set of stimuli. Two distinct effects were observed: Induction judgments were more affected by argument length, and deduction judgments were more affected by validity. In Experiment 2, fluency was manipulated by displaying the materials in a low-contrast font, leading to increased sensitivity to logical validity. Several variants of 1-process and 2-process models of reasoning were assessed against the results. A 1-process model that assumed the same scale of argument strength underlies induction and deduction was not successful. A 2-process model that assumed separate, continuous informational dimensions of apparent deductive validity and associative strength gave the more successful account. (c) 2009 APA, all rights reserved.

  19. Are there interactive effects of physiological and radiative forcing produced by increased CO2 concentration on changes of land hydrological cycle?

    NASA Astrophysics Data System (ADS)

    Peng, Jing; Dan, Li; Dong, Wenjie

    2014-01-01

    Three coupled climate-carbon cycle models including CESM (Community Earth System Model), CanEsm (the Canadian Centre for Climate Modelling and Analysis Earth System Model) and BCC (Beijing Climate Center Climate System Model) were used to estimate whether changes in land hydrological cycle responded to the interactive effects of CO2-physiological forcing and CO2-radiative forcing. No signs could be indicated that the interactive effects of CO2-physiological forcing and CO2-radiative forcing on the hydrological variables (e.g. precipitation, evapotranspiration and runoff) were detected at global and regional scales. For each model, increases in precipitation, evapotranspiration and runoff (e.g. 0.37, 0.18 and 0.25 mm/year2) were simulated in response to CO2-radiative forcing (experiment M3). Decreases in precipitation and evapotranspiration (about - 0.02 and - 0.09 mm/year2) were captured if the CO2 physiological effect was only accounted for (experiment M2). In this experiment, a reverse sign in runoff (the increase of 0.08 mm/year2) in contrast to M3 is presented. All models simulated the same signs across Eastern Asia in response to the CO2 physiological forcing and radiative forcing: increases in precipitation and evapotranspiration only considering greenhouse effect; reductions in precipitation and evapotranspiration in response to CO2-physiological effect; and enhanced trends in runoff from all experiments. However, there was still a large uncertainty on the magnitude of the effect of transpiration on runoff (decreased transpiration accounting for 8% to 250% of the increased runoff) from the three models. Two models (CanEsm and BCC) attributed most of the increase in runoff to the decrease in transpiration if the CO2-physiological effect was only accounted for, whereas CESM exhibited that the decrease in transpiration could not totally explain the increase in runoff. The attribution of the CO2-physiological forcing to changes in stomatal conductance versus changes in vegetation structure (e.g. increased Leaf Area Index) is an issue to discuss, and among the three models, no agreement appeared.

  20. Display size effects in visual search: analyses of reaction time distributions as mixtures.

    PubMed

    Reynolds, Ann; Miller, Jeff

    2009-05-01

    In a reanalysis of data from Cousineau and Shiffrin (2004) and two new visual search experiments, we used a likelihood ratio test to examine the full distributions of reaction time (RT) for evidence that the display size effect is a mixture-type effect that occurs on only a proportion of trials, leaving RT in the remaining trials unaffected, as is predicted by serial self-terminating search models. Experiment 1 was a reanalysis of Cousineau and Shiffrin's data, for which a mixture effect had previously been established by a bimodal distribution of RTs, and the results confirmed that the likelihood ratio test could also detect this mixture. Experiment 2 applied the likelihood ratio test within a more standard visual search task with a relatively easy target/distractor discrimination, and Experiment 3 applied it within a target identification search task within the same types of stimuli. Neither of these experiments provided any evidence for the mixture-type display size effect predicted by serial self-terminating search models. Overall, these results suggest that serial self-terminating search models may generally be applicable only with relatively difficult target/distractor discriminations, and then only for some participants. In addition, they further illustrate the utility of analysing full RT distributions in addition to mean RT.

  1. Sounding Rocket Microgravity Experiments Elucidating Diffusive and Radiative Transport Effects on Flame Spread over Thermally-Thick Solids

    NASA Technical Reports Server (NTRS)

    Olson, Sandra L.; Hegde, U.; Bhattacharjee, S.; Deering, J. L.; Tang, L.; Altenkirch, R. A.

    2003-01-01

    A series of 6-minute microgravity combustion experiments of opposed flow flame spread over thermally-thick PMMA has been conducted to extend data previously reported at high opposed flows to almost two decades lower in flow. The effect of flow velocity on flame spread shows a square root power law dependence rather than the linear dependence predicted by thermal theory. The experiments demonstrate that opposed flow flame spread is viable to very low velocities and more robust than expected from the numerical model, which predicts that at very low velocities (less than 5 centimeters per second), flame spread rates fall off more rapidly as flow is reduced. It is hypothesized that the enhanced flame spread observed in the experiments may be due to three- dimensional hydrodynamic effects, which are not included in the zero-gravity, two-dimensional hydrodynamic model. The effect of external irradiation was found to be more complex that the model predicted over the 0-2 Watts per square centimeter range. In the experiments, the flame compensated for the increased irradiation by stabilizing farther from the surface. A surface energy balance reveals that the imposed flux was at least partially offset by a reduced conductive flux from the increased standoff distance, so that the effect on flame spread was weaker than anticipated.

  2. Structural Equation Modeling of Cultural Competence of Nurses Caring for Foreign Patients.

    PubMed

    Ahn, Jung-Won

    2017-03-01

    This study aimed to construct and test a hypothetical model including factors related to the cultural competence of nurses caring for foreign patients. The transcultural nursing immersion experience model and anxiety/uncertainty management theory were used to verify the paths between the variables. The exogenous variables were multicultural experience, ethnocentric attitude, and organizational cultural competence support. The endogenous variables were intercultural anxiety, intercultural uncertainty, coping strategy, and cultural competence. Participants were 275 nurses working in general hospitals in Seoul and Kyung-Gi Do, Korea. Each nurse in this study had experience of caring for over 10 foreign patients. Data were collected using a structured questionnaire and analyzed with SPSS statistical software with the added AMOS module. The overall fitness indices of the hypothetical model were a good fit. Multicultural experience, ethnocentric attitude, organizational cultural competence support, and intercultural uncertainty were found to have a direct and indirect effect on the cultural competence of nurses while coping strategy only had a direct effect. Intercultural anxiety did not have a significant effect on cultural competence. This model explained 59.1% of the variance in the nurses' cultural competence when caring for foreign patients. Nurses' cultural competence can be developed by offering multicultural nursing education, increasing direct/indirect multicultural experience, and sharing problem-solving experience to promote the coping ability of nurses. Organizational support can be achieved by preparing relevant personnel and resources. Subsequently, the quality of nursing care for foreign patients' will be ultimately improved. Copyright © 2017. Published by Elsevier B.V.

  3. A Study on Phase Changes of Heterogeneous Composite Materials

    NASA Astrophysics Data System (ADS)

    Hirasawa, Yoshio; Saito, Akio; Takegoshi, Eisyun

    In this study, a phase change process in heterogeneous composite materials which consist of water and coiled copper wires as conductive solid is investigated by four kinds of typical calculation models : 1) model-1 in which the effective thermal conductivity of the composite material is used, 2) model-2 in which a fin metal acts for many conductive solids, 3) model-3 in which the effective thermal conductivities between nodes are estimated and three-dimensional calculation is performed, 4) model-4 proposed by authors in the previous paper in which effective thermal conductivity is not needed. Consequently, model-1 showed the phase change rate considerably lower than the experimental results. Model-2 gave the larger amount of the phase change rate. Model-3 agreed well with the experiment in the case of small coil diameter and relatively large Vd. Model-4 showed a very well agreement with the experiment in the range of this study.

  4. Negative evaluations of self and others, and peer victimization as mediators of the relationship between childhood adversity and psychotic experiences in adolescence: the moderating role of loneliness.

    PubMed

    Murphy, Siobhan; Murphy, Jamie; Shevlin, Mark

    2015-09-01

    Previous research has identified an association between traumatic experiences and psychotic symptoms. Few studies, however, have explored the underlying mechanisms and contingent nature of these associations in an integrated model. This study aimed to test a moderated mediation model of negative childhood experiences, associated cognitive processes, and psychotic experiences within a context of adolescent loneliness. Cross-sectional survey. A total of 785 Northern Irish secondary school adolescents completed the survey. A moderated mediation model was specified and tested. Childhood experiences of threat and subordination were directly associated with psychotic experiences. Analyses indicated that peer victimization was a mediator of this effect and that loneliness moderated this mediated effect. A new model is proposed to provide an alternative framework for assessing the association between trauma and psychotic experience in adolescence that recognizes loneliness as a significant contextual moderator that can potentially strengthen the trauma-psychosis relationship. Moderated mediation analyses poses an alternative framework to the understanding of trauma-psychosis associations Adolescent loneliness is a vulnerability factor within this association Data are based on a Northern Irish sample with relatively low levels of loneliness Cross-sectional data cannot explore the developmental course of these experiences in adolescence. © 2015 The British Psychological Society.

  5. Convection Effects During Bulk Transparent Alloy Solidification in DECLIC-DSI and Phase-Field Simulations in Diffusive Conditions

    NASA Astrophysics Data System (ADS)

    Mota, F. L.; Song, Y.; Pereda, J.; Billia, B.; Tourret, D.; Debierre, J.-M.; Trivedi, R.; Karma, A.; Bergeon, N.

    2017-08-01

    To study the dynamical formation and evolution of cellular and dendritic arrays under diffusive growth conditions, three-dimensional (3D) directional solidification experiments were conducted in microgravity on a model transparent alloy onboard the International Space Station using the Directional Solidification Insert in the DEvice for the study of Critical LIquids and Crystallization. Selected experiments were repeated on Earth under gravity-driven fluid flow to evidence convection effects. Both radial and axial macrosegregation resulting from convection are observed in ground experiments, and primary spacings measured on Earth and microgravity experiments are noticeably different. The microgravity experiments provide unique benchmark data for numerical simulations of spatially extended pattern formation under diffusive growth conditions. The results of 3D phase-field simulations highlight the importance of accurately modeling thermal conditions that strongly influence the front recoil of the interface and the selection of the primary spacing. The modeling predictions are in good quantitative agreements with the microgravity experiments.

  6. Design and Analysis of AN Static Aeroelastic Experiment

    NASA Astrophysics Data System (ADS)

    Hou, Ying-Yu; Yuan, Kai-Hua; Lv, Ji-Nan; Liu, Zi-Qiang

    2016-06-01

    Static aeroelastic experiments are very common in the United States and Russia. The objective of static aeroelastic experiments is to investigate deformation and loads of elastic structure in flow field. Generally speaking, prerequisite of this experiment is that the stiffness distribution of structure is known. This paper describes a method for designing experimental models, in the case where the stiffness distribution and boundary condition of a real aircraft are both uncertain. The stiffness distribution form of the structure can be calculated via finite element modeling and simulation calculation and F141 steels and rigid foam are used to make elastic model. In this paper, the design and manufacturing process of static aeroelastic models is presented and a set of experiment model was designed to simulate the stiffness of the designed wings, a set of experiments was designed to check the results. The test results show that the experimental method can effectively complete the design work of elastic model. This paper introduces the whole process of the static aeroelastic experiment, and the experimental results are analyzed. This paper developed a static aeroelasticity experiment technique and established an experiment model targeting at the swept wing of a certain kind of large aspect ratio aircraft.

  7. The Experimental Research on E-Learning Instructional Design Model Based on Cognitive Flexibility Theory

    NASA Astrophysics Data System (ADS)

    Cao, Xianzhong; Wang, Feng; Zheng, Zhongmei

    The paper reports an educational experiment on the e-Learning instructional design model based on Cognitive Flexibility Theory, the experiment were made to explore the feasibility and effectiveness of the model in promoting the learning quality in ill-structured domain. The study performed the experiment on two groups of students: one group learned through the system designed by the model and the other learned by the traditional method. The results of the experiment indicate that the e-Learning designed through the model is helpful to promote the intrinsic motivation, learning quality in ill-structured domains, ability to resolve ill-structured problem and creative thinking ability of the students.

  8. Investigation of models for large-scale meteorological prediction experiments

    NASA Technical Reports Server (NTRS)

    Spar, J.

    1973-01-01

    Studies are reported of the long term responses of the model atmosphere to anomalies in snow cover and sea surface temperature. An abstract of a previously issued report on the computed response to surface anomalies in a global atmospheric model is presented, and the experiments on the effects of transient sea surface temperature on the Mintz-Arakawa atmospheric model are reported.

  9. Do STEM fields need a makeover?: The effect of role model femininity on men and women's interest in STEM

    NASA Astrophysics Data System (ADS)

    Howard, Carolynn

    Women continue to be underrepresented in science, technology, engineering, and mathematics (STEM) fields. This lack of women is problematic because it diminishes perspective, input, and expertise that women could provide. Consequently, this thesis examined the benefits of exposure to peer role models for increasing women's interest in STEM, which may ultimately lead more women to enter STEM fields. The role model research to date has amassed considerable evidence showing that role model exposure is beneficial; yet, questions still remain about what makes these role models effective. Accordingly, this thesis investigated whether feminine female role models increase women's interest in STEM and improve their perceptions of female STEM role models relative to "neutral" female role models. Across three experiments men and women were exposed to role models and their interest in STEM was measured. All experiments exposed participants to one of three articles about a peer role model (a female role model who embodies femininity (e.g. wears makeup), a female role model who has gender neutral qualities/behaviors [e.g., works hard], or a male role model who embodies neutral traits) and Experiments 2 and 3 had a fourth control condition in which participants read about the history of SDSU (a control condition). In the first two experiments interest in physics was measured using an adapted version of the STEM Career Interest Survey (CIS). Experiment 3 used an adapted version of the STEM CIS scale, but measured overall interest in STEM by including subscales for each of the four STEM areas with a composite score serving as the primary dependent variable. Experiments 1 and 2 demonstrated that women's interest in physics was no different than men's after exposure to a feminine female role model compared to a neutral female and neutral male role model. Furthermore, women's interest in physics was greater in the feminine condition compared to all other conditions for the first two experiments, thus demonstrating that a competent feminine role model may be useful in piquing women's interest in physics. Experiment 3, however, did not display this pattern for women's interest in STEM overall.

  10. Differentiating the Differentiation Models: A Comparison of the Retrieving Effectively from Memory Model (REM) and the Subjective Likelihood Model (SLiM)

    ERIC Educational Resources Information Center

    Criss, Amy H.; McClelland, James L.

    2006-01-01

    The subjective likelihood model [SLiM; McClelland, J. L., & Chappell, M. (1998). Familiarity breeds differentiation: a subjective-likelihood approach to the effects of experience in recognition memory. "Psychological Review," 105(4), 734-760.] and the retrieving effectively from memory model [REM; Shiffrin, R. M., & Steyvers, M. (1997). A model…

  11. Investigating the Use of Vicarious and Mastery Experiences in Influencing Early Childhood Education Majors' Self-Efficacy Beliefs

    ERIC Educational Resources Information Center

    Bautista, Nazan Uludag

    2011-01-01

    This study investigated the effectiveness of an Early Childhood Education science methods course that focused exclusively on providing various mastery (i.e., enactive, cognitive content, and cognitive pedagogical) and vicarious experiences (i.e., cognitive self-modeling, symbolic modeling, and simulated modeling) in increasing preservice…

  12. Evaluation of an Imputed Pitch Velocity Model of the Auditory Kappa Effect

    ERIC Educational Resources Information Center

    Henry, Molly J.; McAuley, J. Devin

    2009-01-01

    Three experiments evaluated an imputed pitch velocity model of the auditory kappa effect. Listeners heard 3-tone sequences and judged the timing of the middle (target) tone relative to the timing of the 1st and 3rd (bounding) tones. Experiment 1 held pitch constant but varied the time (T) interval between bounding tones (T = 728, 1,000, or 1,600…

  13. Marital Relationship Quality and Couples' Cognitive Stimulation Practices toward Their Infants: Actor and Partner Effects of White and Hispanic Parents

    ERIC Educational Resources Information Center

    Sotomayor-Peterson, Marcela; Wilhelm, Mari S.; Card, Noel A.

    2011-01-01

    The present study explores actor and partner effects on mothers' and fathers' cognitive stimulation within an Actor-Partner Interdependence Model (APIM). This model allows us to evaluate whether mothers' and fathers' practices are impacted not only by their own experiences but also by their partners' experiences. The APIM treats the couple as the…

  14. The role of patients' explanatory models and daily-lived experience in hypertension self-management.

    PubMed

    Bokhour, Barbara G; Cohn, Ellen S; Cortés, Dharma E; Solomon, Jeffrey L; Fix, Gemmae M; Elwy, A Rani; Mueller, Nora; Katz, Lois A; Haidet, Paul; Green, Alexander R; Borzecki, Ann M; Kressin, Nancy R

    2012-12-01

    Uncontrolled hypertension remains a significant problem for many patients. Few interventions to improve patients' hypertension self-management have had lasting effects. Previous work has focused largely on patients' beliefs as predictors of behavior, but little is understood about beliefs as they are embedded in patients' social contexts. This study aims to explore how patients' "explanatory models" of hypertension (understandings of the causes, mechanisms or pathophysiology, course of illness, symptoms and effects of treatment) and social context relate to their reported daily hypertension self-management behaviors. Semi-structured qualitative interviews with a diverse group of patients at two large urban Veterans Administration Medical centers. PARTICIPANTS (OR PATIENTS OR SUBJECTS): African-American, white and Latino Veterans Affairs (VA) primary care patients with uncontrolled blood pressure. We conducted thematic analysis using tools of grounded theory to identify key themes surrounding patients' explanatory models, social context and hypertension management behaviors. Patients' perceptions of the cause and course of hypertension, experiences of hypertension symptoms, and beliefs about the effectiveness of treatment were related to different hypertension self-management behaviors. Moreover, patients' daily-lived experiences, such as an isolated lifestyle, serious competing health problems, a lack of habits and routines, barriers to exercise and prioritizing lifestyle choices, also interfered with optimal hypertension self-management. Designing interventions to improve patients' hypertension self-management requires consideration of patients' explanatory models and their daily-lived experience. We propose a new conceptual model - the dynamic model of hypertension self-management behavior - which incorporates these key elements of patients' experiences.

  15. Observer age and the social transmission of attractiveness in humans: Younger women are more influenced by the choices of popular others than older women.

    PubMed

    Little, Anthony C; Caldwell, Christine A; Jones, Benedict C; DeBruine, Lisa M

    2015-08-01

    Being paired with an attractive partner increases perceptual judgements of attractiveness in humans. We tested experimentally for prestige bias, whereby individuals follow the choices of prestigious others. Women rated the attractiveness of photographs of target males which were paired with either popular or less popular model female partners. We found that pairing a photo of a man with a woman presented as his partner positively influenced the attractiveness of the man when the woman was presented as more popular (Experiment 1). Further, this effect was stronger in younger participants compared to older participants (Experiment 1). Reversing the target and model such that women were asked to rate women paired with popular and less popular men revealed no effect of model popularity and this effect was unrelated to participant age (Experiment 2). An additional experiment confirmed that participant age and not stimulus age primarily influenced the tendency to follow others' preferences in Experiment 1 (Experiment 3). We also confirmed that our manipulations of popularity lead to variation in rated prestige (Experiment 4). These results suggest a sophisticated model-based bias in social learning whereby individuals are most influenced by the choices of those who have high popularity/prestige. Furthermore, older individuals moderate their use of such social information and so this form of social learning appears strongest in younger women. © 2014 The British Psychological Society.

  16. Reduced Gravity Studies of Soret Transport Effects in Liquid Fuel Combustion

    NASA Technical Reports Server (NTRS)

    Shaw, Benjamin D.

    2004-01-01

    Soret transport, which is mass transport driven by thermal gradients, can be important in practical flames as well as laboratory flames by influencing transport of low molecular weight species (e.g., monatomic and diatomic hydrogen). In addition, gas-phase Soret transport of high molecular weight fuel species that are present in practical liquid fuels (e.g., octane or methanol) can be significant in practical flames (Rosner et al., 2000; Dakhlia et al., 2002) and in high pressure droplet evaporation (Curtis and Farrell, 1992), and it has also been shown that Soret transport effects can be important in determining oxygen diffusion rates in certain classes of microgravity droplet combustion experiments (Aharon and Shaw, 1998). It is thus useful to obtain information on flames under conditions where Soret effects can be clearly observed. This research is concerned with investigating effects of Soret transport on combustion of liquid fuels, in particular liquid fuel droplets. Reduced-gravity is employed to provide an ideal (spherically-symmetrical) experimental model with which to investigate effects of Soret transport on combustion. The research will involve performing reduced-gravity experiments on combustion of liquid fuel droplets in environments where Soret effects significantly influence transport of fuel and oxygen to flame zones. Experiments will also be performed where Soret effects are not expected to be important. Droplets initially in the 0.5 to 1 mm size range will be burned. Data will be obtained on influences of Soret transport on combustion characteristics (e.g., droplet burning rates, droplet lifetimes, gas-phase extinction, and transient flame behaviors) under simplified geometrical conditions that are most amenable to theoretical modeling (i.e., spherical symmetry). The experiments will be compared with existing theoretical models as well as new models that will be developed. Normal gravity experiments will also be performed.

  17. Adapting Evaluations of Alternative Payment Models to a Changing Environment.

    PubMed

    Grannemann, Thomas W; Brown, Randall S

    2018-04-01

    To identify the most robust methods for evaluating alternative payment models (APMs) in the emerging health care delivery system environment. We assess the impact of widespread testing of alternative payment models on the ability to find credible comparison groups. We consider the applicability of factorial research designs for assessing the effects of these models. The widespread adoption of alternative payment models could effectively eliminate the possibility of comparing APM results with a "pure" control or comparison group unaffected by other interventions. In this new environment, factorial experiments have distinct advantages over the single-model experimental or quasi-experimental designs that have been the mainstay of recent tests of Medicare payment and delivery models. The best prospects for producing definitive evidence of the effects of payment incentives for APMs include fractional factorial experiments that systematically vary requirements and payment provisions within a payment model. © Health Research and Educational Trust.

  18. Experiments and Modeling of G-Jitter Fluid Mechanics

    NASA Technical Reports Server (NTRS)

    Leslie, F. W.; Ramachandran, N.; Whitaker, Ann F. (Technical Monitor)

    2002-01-01

    While there is a general understanding of the acceleration environment onboard an orbiting spacecraft, past research efforts in the modeling and analysis area have still not produced a general theory that predicts the effects of multi-spectral periodic accelerations on a general class of experiments nor have they produced scaling laws that a prospective experimenter can use to assess how an experiment might be affected by this acceleration environment. Furthermore, there are no actual flight experimental data that correlates heat or mass transport with measurements of the periodic acceleration environment. The present investigation approaches this problem with carefully conducted terrestrial experiments and rigorous numerical modeling for better understanding the effect of residual gravity and gentler on experiments. The approach is to use magnetic fluids that respond to an imposed magnetic field gradient in much the same way as fluid density responds to a gravitational field. By utilizing a programmable power source in conjunction with an electromagnet, both static and dynamic body forces can be simulated in lab experiments. The paper provides an overview of the technique and includes recent results from the experiments.

  19. Active machine learning-driven experimentation to determine compound effects on protein patterns

    PubMed Central

    Naik, Armaghan W; Kangas, Joshua D; Sullivan, Devin P; Murphy, Robert F

    2016-01-01

    High throughput screening determines the effects of many conditions on a given biological target. Currently, to estimate the effects of those conditions on other targets requires either strong modeling assumptions (e.g. similarities among targets) or separate screens. Ideally, data-driven experimentation could be used to learn accurate models for many conditions and targets without doing all possible experiments. We have previously described an active machine learning algorithm that can iteratively choose small sets of experiments to learn models of multiple effects. We now show that, with no prior knowledge and with liquid handling robotics and automated microscopy under its control, this learner accurately learned the effects of 48 chemical compounds on the subcellular localization of 48 proteins while performing only 29% of all possible experiments. The results represent the first practical demonstration of the utility of active learning-driven biological experimentation in which the set of possible phenotypes is unknown in advance. DOI: http://dx.doi.org/10.7554/eLife.10047.001 PMID:26840049

  20. Impacts, Effectiveness and Regional Inequalities of the GeoMIP G1 to G4 Solar Radiation Management Scenarios

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yu, Xiaoyong; Moore, John; Cui, Xuefeng

    We evaluate the regional effectiveness of solar radiation management (SRM) to compensate for simultaneous changes in temperature and precipitation induced by increased greenhouse gas concentrations. We analyze results from multiple earth system models under four Geoengineering Model Intercomparison Project(GeoMIP) experiments with a modified form of the Residual Climate Response approach. Under the solar dimming geoengineering experiments G1(4xCO2) and G2(increasing CO2 by 1% per year), global average temperature is successfully restored to pre-industrial level over 50 years simulations. However, these two SRM experiments also produce a robust global precipitation decrease. The stratospheric aerosol GeoMIP geoengineering experiment, G4 has significantly greater regionalmore » inequality and lower effectiveness for compensating temperature change than G1 and G2. G4 also has significantly larger regional inequality for compensating precipitation change than G1and G2. However, there is no significant difference between precipitation change compensation effectiveness of G4 and G2, though there is much larger across model variability in G4 results. G3 has significant greater regional inequality for compensating temperature change than G1 and G2, and has significant lower effectiveness than G1. The effectiveness of four SRMs to compensate for temperature change is much higher than for precipitation. The large cross-model variation in adjustment percentage of compensated SAT and precipitation change by SRM to achieve optimal compensation effectiveness shed a light on the uncertainty accumulation effect in optimizing compensation effectiveness of SRM.« less

  1. The influence of initial and surface boundary conditions on a model-generated January climatology

    NASA Technical Reports Server (NTRS)

    Wu, K. F.; Spar, J.

    1981-01-01

    The influence on a model-generated January climate of various surface boundary conditions, as well as initial conditions, was studied by using the GISS coarse-mesh climate model. Four experiments - two with water planets, one with flat continents, and one with mountains - were used to investigate the effects of initial conditions, and the thermal and dynamical effects of the surface on the model generated-climate. However, climatological mean zonal-symmetric sea surface temperature is used in all four runs over the model oceans. Moreover, zero ground wetness and uniform ground albedo except for snow are used in the last experiments.

  2. Host Model Uncertainty in Aerosol Radiative Forcing Estimates - The AeroCom Prescribed Experiment

    NASA Astrophysics Data System (ADS)

    Stier, P.; Kinne, S.; Bellouin, N.; Myhre, G.; Takemura, T.; Yu, H.; Randles, C.; Chung, C. E.

    2012-04-01

    Anthropogenic and natural aerosol radiative effects are recognized to affect global and regional climate. However, even for the case of identical aerosol emissions, the simulated direct aerosol radiative forcings show significant diversity among the AeroCom models (Schulz et al., 2006). Our analysis of aerosol absorption in the AeroCom models indicates a larger diversity in the translation from given aerosol radiative properties (absorption optical depth) to actual atmospheric absorption than in the translation of a given atmospheric burden of black carbon to the radiative properties (absorption optical depth). The large diversity is caused by differences in the simulated cloud fields, radiative transfer, the relative vertical distribution of aerosols and clouds, and the effective surface albedo. This indicates that differences in host model (GCM or CTM hosting the aerosol module) parameterizations contribute significantly to the simulated diversity of aerosol radiative forcing. The magnitude of these host model effects in global aerosol model and satellites retrieved aerosol radiative forcing estimates cannot be estimated from the diagnostics of the "standard" AeroCom forcing experiments. To quantify the contribution of differences in the host models to the simulated aerosol radiative forcing and absorption we conduct the AeroCom Prescribed experiment, a simple aerosol model and satellite retrieval intercomparison with prescribed highly idealised aerosol fields. Quality checks, such as diagnostic output of the 3D aerosol fields as implemented in each model, ensure the comparability of the aerosol implementation in the participating models. The simulated forcing variability among the models and retrievals is a direct measure of the contribution of host model assumptions to the uncertainty in the assessment of the aerosol radiative effects. We will present the results from the AeroCom prescribed experiment with focus on the attribution to the simulated variability to parametric and structural model uncertainties. This work will help to prioritise areas for future model improvements and ultimately lead to uncertainty reduction.

  3. Examining robustness of model selection with half-normal and LASSO plots for unreplicated factorial designs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jang, Dae -Heung; Anderson-Cook, Christine Michaela

    When there are constraints on resources, an unreplicated factorial or fractional factorial design can allow efficient exploration of numerous factor and interaction effects. A half-normal plot is a common graphical tool used to compare the relative magnitude of effects and to identify important effects from these experiments when no estimate of error from the experiment is available. An alternative is to use a least absolute shrinkage and selection operation plot to examine the pattern of model selection terms from an experiment. We examine how both the half-normal and least absolute shrinkage and selection operation plots are impacted by the absencemore » of individual observations or an outlier, and the robustness of conclusions obtained from these 2 techniques for identifying important effects from factorial experiments. As a result, the methods are illustrated with 2 examples from the literature.« less

  4. Examining robustness of model selection with half-normal and LASSO plots for unreplicated factorial designs

    DOE PAGES

    Jang, Dae -Heung; Anderson-Cook, Christine Michaela

    2017-04-12

    When there are constraints on resources, an unreplicated factorial or fractional factorial design can allow efficient exploration of numerous factor and interaction effects. A half-normal plot is a common graphical tool used to compare the relative magnitude of effects and to identify important effects from these experiments when no estimate of error from the experiment is available. An alternative is to use a least absolute shrinkage and selection operation plot to examine the pattern of model selection terms from an experiment. We examine how both the half-normal and least absolute shrinkage and selection operation plots are impacted by the absencemore » of individual observations or an outlier, and the robustness of conclusions obtained from these 2 techniques for identifying important effects from factorial experiments. As a result, the methods are illustrated with 2 examples from the literature.« less

  5. Meson exchange current (MEC) models in neutrino interaction generators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Katori, Teppei

    2015-05-15

    Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent program in neutrino interaction physics for current and future oscillation experiments. Such processes are believed to be responsible for the event excesses observed by recent neutrino experiments. The 2p-2h effect is dominated by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission from the primary vertex, instead of a single nucleon emission from the charged-current quasi-elastic (CCQE) interaction. Current and future high resolution experiments can potentially nail down this effect. For this reason, there are world wide efforts to model and implement this process inmore » neutrino interaction simulations. In these proceedings, I would like to describe how this channel is modeled in neutrino interaction generators.« less

  6. Statistical validation and an empirical model of hydrogen production enhancement found by utilizing passive flow disturbance in the steam-reformation process

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Erickson, Paul A.; Liao, Chang-hsien

    2007-11-15

    A passive flow disturbance has been proven to enhance the conversion of fuel in a methanol-steam reformer. This study presents a statistical validation of the experiment based on a standard 2{sup k} factorial experiment design and the resulting empirical model of the enhanced hydrogen producing process. A factorial experiment design was used to statistically analyze the effects and interactions of various input factors in the experiment. Three input factors, including the number of flow disturbers, catalyst size, and reactant flow rate were investigated for their effects on the fuel conversion in the steam-reformation process. Based on the experimental results, anmore » empirical model was developed and further evaluated with an uncertainty analysis and interior point data. (author)« less

  7. Field experimental data for crop modeling of wheat growth response to nitrogen fertilizer, elevated CO2, water stress, and high temperature

    USDA-ARS?s Scientific Manuscript database

    Field experimental data of five experiments covering a wide range Field experimental data of five experiments covering a wide range of growing conditions are assembled for wheat growth and cropping systems modeling. The data include (i) an experiment on interactive effects of elevated CO2 by water a...

  8. Online Community-Based Learning as the Practice of Freedom: The Online Capstone Experience at Portland State University

    ERIC Educational Resources Information Center

    Arthur, Deborah Smith; Newton-Calvert, Zapoura

    2015-01-01

    Given the design of Portland State University's (PSU) undergraduate curriculum culminating in a capstone experience, the dramatic growth in online courses and online enrollments required a re-thinking of the capstone model to ensure all students could participate in this effective learning model and have a powerful learning experience. In recent…

  9. Rapid performance modeling and parameter regression of geodynamic models

    NASA Astrophysics Data System (ADS)

    Brown, J.; Duplyakin, D.

    2016-12-01

    Geodynamic models run in a parallel environment have many parameters with complicated effects on performance and scientifically-relevant functionals. Manually choosing an efficient machine configuration and mapping out the parameter space requires a great deal of expert knowledge and time-consuming experiments. We propose an active learning technique based on Gaussion Process Regression to automatically select experiments to map out the performance landscape with respect to scientific and machine parameters. The resulting performance model is then used to select optimal experiments for improving the accuracy of a reduced order model per unit of computational cost. We present the framework and evaluate its quality and capability using popular lithospheric dynamics models.

  10. Using the Flow-3D General Moving Object Model to Simulate Coupled Liquid Slosh - Container Dynamics on the SPHERES Slosh Experiment: Aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Schulman, Richard; Kirk, Daniel; Marsell, Brandon; Roth, Jacob; Schallhorn, Paul

    2013-01-01

    The SPHERES Slosh Experiment (SSE) is a free floating experimental platform developed for the acquisition of long duration liquid slosh data aboard the International Space Station (ISS). The data sets collected will be used to benchmark numerical models to aid in the design of rocket and spacecraft propulsion systems. Utilizing two SPHERES Satellites, the experiment will be moved through different maneuvers designed to induce liquid slosh in the experiment's internal tank. The SSE has a total of twenty-four thrusters to move the experiment. In order to design slosh generating maneuvers, a parametric study with three maneuvers types was conducted using the General Moving Object (GMO) model in Flow-30. The three types of maneuvers are a translation maneuver, a rotation maneuver and a combined rotation translation maneuver. The effectiveness of each maneuver to generate slosh is determined by the deviation of the experiment's trajectory as compared to a dry mass trajectory. To fully capture the effect of liquid re-distribution on experiment trajectory, each thruster is modeled as an independent force point in the Flow-3D simulation. This is accomplished by modifying the total number of independent forces in the GMO model from the standard five to twenty-four. Results demonstrate that the most effective slosh generating maneuvers for all motions occurs when SSE thrusters are producing the highest changes in SSE acceleration. The results also demonstrate that several centimeters of trajectory deviation between the dry and slosh cases occur during the maneuvers; while these deviations seem small, they are measureable by SSE instrumentation.

  11. Recent Experiments at the Gottingen Aerodynamic Institute

    NASA Technical Reports Server (NTRS)

    Ackeret, J

    1925-01-01

    This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).

  12. Relevance of the hadronic interaction model in the interpretation of multiple muon data as detected with the MACRO experiment

    NASA Astrophysics Data System (ADS)

    Ambrosio, M.; Antolini, R.; Aramo, C.; Auriemma, G.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bisi, V.; Bloise, C.; Bower, C.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Castellano, M.; Cecchini, S.; Cei, F.; Chiarella, V.; Coutu, S.; de Benedictis, L.; de Cataldo, G.; Dekhissi, H.; de Marzo, C.; de Mitri, I.; de Vincenzi, M.; di Credico, A.; Erriquez, O.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Grassi, M.; Gray, L.; Grillo, A.; Guarino, F.; Guarnaccia, P.; Gustavino, C.; Habig, A.; Hanson, K.; Hawthorne, A.; Heinz, R.; Iarocci, E.; Katsavounidis, E.; Kearns, E.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Longley, N. P.; Longo, M. J.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Manzoor, S.; Margiotta Neri, A.; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Mazzotta, C.; Michael, D. G.; Mikheyev, S.; Miller, L.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicoló, D.; Nolty, R.; Okada, C.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Petrera, S.; Pistilli, P.; Popa, V.; Rainó, A.; Rastelli, A.; Reynoldson, J.; Ronga, F.; Rubizzo, U.; Sanzgiri, A.; Satriano, C.; Satta, L.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Serra-Lugaresi, P.; Severi, M.; Sioli, M.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarlé, G.; Togo, V.; Walter, C. W.; Webb, R.

    1999-03-01

    With the aim of discussing the effect of the possible sources of systematic uncertainties in simulation models, the analysis of multiple muon events from the MACRO experiment at Gran Sasso is reviewed. In particular, the predictions from different currently available hadronic interaction models are compared.

  13. Modeling Japan-South Seas trade in forest products.

    Treesearch

    J.R. Vincent

    1987-01-01

    The international trade of forest products has generated increasing research interest, yet experience with modeling such trade is limited. Primary issues include the effects of trade barriers and exchange rates on trade patterns and national welfare. This paper attempts to add to experience by modeling hardwood log, lumber, and plywood trade in a region that has been...

  14. Complexity of Choice: Teachers' and Students' Experiences Implementing a Choice-Based Comprehensive School Health Model

    ERIC Educational Resources Information Center

    Sulz, Lauren; Gibbons, Sandra; Naylor, Patti-Jean; Wharf Higgins, Joan

    2016-01-01

    Background: Comprehensive School Health models offer a promising strategy to elicit changes in student health behaviours. To maximise the effect of such models, the active involvement of teachers and students in the change process is recommended. Objective: The goal of this project was to gain insight into the experiences and motivations of…

  15. Enhancing the Effectiveness of Carbon Dioxide Flooding by Managing Asphaltene Precipitation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Deo, Milind D.

    2002-02-21

    This project was undertaken to understand fundamental aspects of carbon dioxide (CO2) induced asphaltene precipitation. Oil and asphaltene samples from the Rangely field in Colorado were used for most of the project. The project consisted of pure component and high-pressure, thermodynamic experiments, thermodynamic modeling, kinetic experiments and modeling, targeted corefloods and compositional modeling.

  16. Dissociation mediates the relationship between peer victimization and hallucinatory experiences among early adolescents.

    PubMed

    Yamasaki, Syudo; Ando, Shuntaro; Koike, Shinsuke; Usami, Satoshi; Endo, Kaori; French, Paul; Sasaki, Tsukasa; Furukawa, Toshi A; Hasegawa-Hiraiwa, Mariko; Kasai, Kiyoto; Nishida, Atsushi

    2016-06-01

    Peer victimization increases the risk of experiencing psychotic symptoms among clinical and general populations, but the mechanism underlying this association remains unclear. Dissociation, which is related to peer victimization and hallucinatory experiences, has been demonstrated as a significant mediator in the relation between childhood victimization and hallucinatory experience among adult patients with psychosis. However, no studies have examined the mediating effect of dissociation in a general early adolescent population. We examined whether dissociation mediates the relationship between peer victimization and hallucinatory experiences among 10-year-old adolescents using a population-based cross-sectional survey of early adolescents and their main parent (Tokyo Early Adolescence Survey; N  = 4478). We examined the mediating effect of dissociation, as well as external locus of control and depressive symptoms, on the relationship between peer victimization and hallucinatory experiences using path analysis. The model assuming mediation effects indicated good model fit (comparative fit index = .999; root mean square error of approximation = .015). The mediation effect between peer victimization and hallucination via dissociation (standardized indirect effect = .038, p  < .001) was statistically significant, whereas the mediation effects of depressive symptoms (standardized indirect effect = -.0066, p  = 0.318) and external locus of control (standardized indirect effect = .0024, p  = 0.321) were not significant. These results suggest that dissociation is a mediator in the relation between peer victimization and hallucinatory experiences in early adolescence. For appropriate intervention strategies, assessing dissociation and peer victimization as they affect hallucinatory experiences is necessary.

  17. Long-term Ecosystem Experiments, Data Assimilation, and Meta-Analysis

    NASA Astrophysics Data System (ADS)

    Hungate, B. A.; Van Groenigen, K. J.; Osenberg, C. W.; van Gestel, N.

    2015-12-01

    Land ecosystems affect climate and the atmosphere, and climate and atmospheric change affects ecosystems. Syntheses of ecosystem experiments investigating their responses to environmental change holds promise for understanding how to model these interactions, and thereby gain insight into Earth's future biosphere, atmosphere, and climate. Long-term experiments examining ecosystem responses are thought to be especially important in this effort, for their potential to reveal cumulative and progressive effects, subtle effects initially undetectable experimentally, but manifest more clearly over time, often with stronger implications for modeled responses than the more dramatic, short-term experimental responses. Here, we present new analyses of long-term experiments manipulating temperature, CO2 concentration, and precipitation, testing the general hypothesis that there are common temporal patterns of responses that reveal general biogeochemical characterizing ecosystem responses to these environmental changes. For example, we show that increased carbon input with elevated CO2 stimulates emissions of nitrous oxide and methane, important greenhouse gases, and that effects show no signs of diminishing over the duration of experiments that have documented responses. At the same time, we show that the temporal resolution for this response is limited, pointing to a potential limitation in the ability of experiments to address clearly long-term hypotheses. We also show that warming tends to have limited cumulative effects on total soil carbon stocks in long-term experiments, and explore the mechanisms underlying this response. Finally, we discuss the implications of these findings for models used to simulate long-term ecosystem responses to these environmental forcings, as well as the implications of these findings for the next generation of terrestrial ecosystem experiments.

  18. The effect of air entrapment on the performance of squeeze film dampers: Experiments and analysis

    NASA Astrophysics Data System (ADS)

    Diaz Briceno, Sergio Enrique

    Squeeze film dampers (SFDs) are an effective means to introduce the required damping in rotor-bearing systems. They are a standard application in jet engines and are commonly used in industrial compressors. Yet, lack of understanding of their operation has confined the design of SFDs to a costly trial and error process based on prior experience. The main factor deterring the success of analytical models for the prediction of SFDs' performance lays on the modeling of the dynamic film rupture. Usually, the cavitation models developed for journal bearings are applied to SFDs. Yet, the characteristic motion of the SFD results in the entrapment of air into the oil film, thus producing a bubbly mixture that can not be represented by these models. In this work, an extensive experimental study establishes qualitatively and---for the first time---quantitatively the differences between operation with vapor cavitation and with air entrainment. The experiments show that most operating conditions lead to air entrainment and demonstrate the paramount effect it has on the performance of SFDs, evidencing the limitation of currently available models. Further experiments address the operation of SFDs with controlled bubbly mixtures. These experiments bolster the possibility of modeling air entrapment by representing the lubricant as a homogeneous mixture of air and oil and provide a reliable data base for benchmarking such a model. An analytical model is developed based on a homogeneous mixture assumption and where the bubbles are described by the Rayleigh-Plesset equation. Good agreement is obtained between this model and the measurements performed in the SFD operating with controlled mixtures. A complementary analytical model is devised to estimate the amount of air entrained from the balance of axial flows in the film. A combination of the analytical models for prediction of the air volume fraction and of the hydrodynamic pressures renders promising results for prediction of the performance of SFDs with freely entrained air. The results of this work are of immediate engineering applicability. Furthermore, they represent a firm step to advance the understanding on the effects of air entrapment in the performance of SFD.

  19. Does letter position coding depend on consonant/vowel status? Evidence with the masked priming technique.

    PubMed

    Perea, Manuel; Acha, Joana

    2009-02-01

    Recently, a number of input coding schemes (e.g., SOLAR model, SERIOL model, open-bigram model, overlap model) have been proposed that capture the transposed-letter priming effect (i.e., faster response times for jugde-JUDGE than for jupte-JUDGE). In their current version, these coding schemes do not assume any processing differences between vowels and consonants. However, in a lexical decision task, Perea and Lupker (2004, JML; Lupker, Perea, & Davis, 2008, L&CP) reported that transposed-letter priming effects occurred for consonant transpositions but not for vowel transpositions. This finding poses a challenge for these recently proposed coding schemes. Here, we report four masked priming experiments that examine whether this consonant/vowel dissociation in transposed-letter priming is task-specific. In Experiment 1, we used a lexical decision task and found a transposed-letter priming effect only for consonant transpositions. In Experiments 2-4, we employed a same-different task - a task which taps early perceptual processes - and found a robust transposed-letter priming effect that did not interact with consonant/vowel status. We examine the implications of these findings for the front-end of the models of visual word recognition.

  20. Dynamic Modeling of the Madison Dynamo Experiment

    NASA Astrophysics Data System (ADS)

    Truitt, J. L.; Forest, C. B.; Wright, J. C.

    1999-11-01

    This work focuses on a computer simulation of the Magnetohydrodynamic equations applied in the geometry of the Madison Dynamo Experiemnt. An integration code is used to evolve both the magnetic field and the velocity field numerically in spherical coordinates using a pseudo-spectral algorithm. The focus is to realistically model an experiment to be undertaken by the Madison Dynamo Experiment Group. The first flows studied are the well documented ones of Dudley and James. The main goals of the simulation are to observe the dynamo effect with the back-reaction allowed, to observe the equipartition of magnetic and kinetic energy due to theoretically proposed turbulent effects, and to isolate and study the α and β effects.

  1. Response trajectories capture the continuous dynamics of the size congruity effect.

    PubMed

    Faulkenberry, Thomas J; Cruise, Alexander; Lavro, Dmitri; Shaki, Samuel

    2016-01-01

    In a comparison task involving numbers, the size congruity effect refers to the general finding that responses are usually faster when there is a match between numerical size and physical size (e.g., 2-8) than when there is a mismatch (e.g., 2-8). In the present study, we used computer mouse tracking to test two competing models of the size congruity effect: an early interaction model, where interference occurs at an early representational stage, and a late interaction model, where interference occurs as dynamic competition between response options. In three experiments, we found that the curvature of responses for incongruent trials was greater than for congruent trials. In Experiment 2 we showed that this curvature effect was reliably modulated by the numerical distance between the two stimulus numbers, with large distance pairs exhibiting a larger curvature effect than small distance pairs. In Experiment 3 we demonstrated that the congruity effects persist into response execution. These findings indicate that incongruities between numerical and physical sizes are carried throughout the response process and result from competition between parallel and partially active response options, lending further support to a late interaction model of the size congruity effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. A global parallel model based design of experiments method to minimize model output uncertainty.

    PubMed

    Bazil, Jason N; Buzzard, Gregory T; Rundell, Ann E

    2012-03-01

    Model-based experiment design specifies the data to be collected that will most effectively characterize the biological system under study. Existing model-based design of experiment algorithms have primarily relied on Fisher Information Matrix-based methods to choose the best experiment in a sequential manner. However, these are largely local methods that require an initial estimate of the parameter values, which are often highly uncertain, particularly when data is limited. In this paper, we provide an approach to specify an informative sequence of multiple design points (parallel design) that will constrain the dynamical uncertainty of the biological system responses to within experimentally detectable limits as specified by the estimated experimental noise. The method is based upon computationally efficient sparse grids and requires only a bounded uncertain parameter space; it does not rely upon initial parameter estimates. The design sequence emerges through the use of scenario trees with experimental design points chosen to minimize the uncertainty in the predicted dynamics of the measurable responses of the system. The algorithm was illustrated herein using a T cell activation model for three problems that ranged in dimension from 2D to 19D. The results demonstrate that it is possible to extract useful information from a mathematical model where traditional model-based design of experiments approaches most certainly fail. The experiments designed via this method fully constrain the model output dynamics to within experimentally resolvable limits. The method is effective for highly uncertain biological systems characterized by deterministic mathematical models with limited data sets. Also, it is highly modular and can be modified to include a variety of methodologies such as input design and model discrimination.

  3. Effects of moisture controlled charcoal on indoor thermal and air environments

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hiroshi; Yokogoshi, Midori; Nabeshima, Yuki

    2017-10-01

    It is crucial to remove and control indoor moisture in Japan, especially in hot and humid summers, in order to improve thermal comfort and save energy in buildings. Charcoal for moisture control made from the waste of wood material has attracted attention among many control strategies to control indoor moisture, and it is beginning to be used in houses. However, the basic characteristics of the charcoal to control moisture and remove chemical compounds in indoor air have not been investigated sufficiently. The objective of this study is to clarify the effect of moisture control charcoal on indoor thermal and air environments by a long-term field measurement using two housing scale models with/without charcoal in Toyohashi, Japan. The comparative experiments to investigate the effect of the charcoal on air temperature and humidity for two models with/without charcoal were conducted from 2015 to 2016. Also, the removal performance of volatile organic compound (VOCs) was investigated in the summer of 2015. Four bags of packed charcoal were set on the floor in the attic for one model during the experiment. As a result of the experiments, a significant effect of moisture control was observed in hot and humid season, and the efficient effect of moisture adsorption was obtained by the periodic humidification experiment using a humidifier. Furthermore, the charcoal showed a remarkable performance of VOC removal from indoor air by the injection experiment of formaldehyde.

  4. The effects of delay duration on visual working memory for orientation.

    PubMed

    Shin, Hongsup; Zou, Qijia; Ma, Wei Ji

    2017-12-01

    We used a delayed-estimation paradigm to characterize the joint effects of set size (one, two, four, or six) and delay duration (1, 2, 3, or 6 s) on visual working memory for orientation. We conducted two experiments: one with delay durations blocked, another with delay durations interleaved. As dependent variables, we examined four model-free metrics of dispersion as well as precision estimates in four simple models. We tested for effects of delay time using analyses of variance, linear regressions, and nested model comparisons. We found significant effects of set size and delay duration on both model-free and model-based measures of dispersion. However, the effect of delay duration was much weaker than that of set size, dependent on the analysis method, and apparent in only a minority of subjects. The highest forgetting slope found in either experiment at any set size was a modest 1.14°/s. As secondary results, we found a low rate of nontarget reports, and significant estimation biases towards oblique orientations (but no dependence of their magnitude on either set size or delay duration). Relative stability of working memory even at higher set sizes is consistent with earlier results for motion direction and spatial frequency. We compare with a recent study that performed a very similar experiment.

  5. Effect of level difference between left and right vocal folds on phonation: Physical experiment and theoretical study.

    PubMed

    Tokuda, Isao T; Shimamura, Ryo

    2017-08-01

    As an alternative factor to produce asymmetry between left and right vocal folds, the present study focuses on level difference, which is defined as the distance between the upper surfaces of the bilateral vocal folds in the inferior-superior direction. Physical models of the vocal folds were utilized to study the effect of the level difference on the phonation threshold pressure. A vocal tract model was also attached to the vocal fold model. For two types of different models, experiments revealed that the phonation threshold pressure tended to increase as the level difference was extended. Based upon a small amplitude approximation of the vocal fold oscillations, a theoretical formula was derived for the phonation threshold pressure. This theory agrees with the experiments, especially when the phase difference between the left and right vocal folds is not extensive. Furthermore, an asymmetric two-mass model was simulated with a level difference to validate the experiments as well as the theory. The primary conclusion is that the level difference has a potential effect on voice production especially for patients with an extended level of vertical difference in the vocal folds, which might be taken into account for the diagnosis of voice disorders.

  6. FRAP Analysis: Accounting for Bleaching during Image Capture

    PubMed Central

    Wu, Jun; Shekhar, Nandini; Lele, Pushkar P.; Lele, Tanmay P.

    2012-01-01

    The analysis of Fluorescence Recovery After Photobleaching (FRAP) experiments involves mathematical modeling of the fluorescence recovery process. An important feature of FRAP experiments that tends to be ignored in the modeling is that there can be a significant loss of fluorescence due to bleaching during image capture. In this paper, we explicitly include the effects of bleaching during image capture in the model for the recovery process, instead of correcting for the effects of bleaching using reference measurements. Using experimental examples, we demonstrate the usefulness of such an approach in FRAP analysis. PMID:22912750

  7. Mixed effects versus fixed effects modelling of binary data with inter-subject variability.

    PubMed

    Murphy, Valda; Dunne, Adrian

    2005-04-01

    The question of whether or not a mixed effects model is required when modelling binary data with inter-subject variability and within subject correlation was reported in this journal by Yano et al. (J. Pharmacokin. Pharmacodyn. 28:389-412 [2001]). That report used simulation experiments to demonstrate that, under certain circumstances, the use of a fixed effects model produced more accurate estimates of the fixed effect parameters than those produced by a mixed effects model. The Laplace approximation to the likelihood was used when fitting the mixed effects model. This paper repeats one of those simulation experiments, with two binary observations recorded for every subject, and uses both the Laplace and the adaptive Gaussian quadrature approximations to the likelihood when fitting the mixed effects model. The results show that the estimates produced using the Laplace approximation include a small number of extreme outliers. This was not the case when using the adaptive Gaussian quadrature approximation. Further examination of these outliers shows that they arise in situations in which the Laplace approximation seriously overestimates the likelihood in an extreme region of the parameter space. It is also demonstrated that when the number of observations per subject is increased from two to three, the estimates based on the Laplace approximation no longer include any extreme outliers. The root mean squared error is a combination of the bias and the variability of the estimates. Increasing the sample size is known to reduce the variability of an estimator with a consequent reduction in its root mean squared error. The estimates based on the fixed effects model are inherently biased and this bias acts as a lower bound for the root mean squared error of these estimates. Consequently, it might be expected that for data sets with a greater number of subjects the estimates based on the mixed effects model would be more accurate than those based on the fixed effects model. This is borne out by the results of a further simulation experiment with an increased number of subjects in each set of data. The difference in the interpretation of the parameters of the fixed and mixed effects models is discussed. It is demonstrated that the mixed effects model and parameter estimates can be used to estimate the parameters of the fixed effects model but not vice versa.

  8. Modeling the effect of lithium-induced pedestal profiles on scrape-off-layer turbulence and the heat flux width

    DOE PAGES

    Russell, David A.; D'Ippolito, Daniel A.; Myra, James R.; ...

    2015-09-01

    The effect of lithium (Li) wall coatings on scrape-off-layer (SOL) turbulence in the National Spherical Torus Experiment (NSTX) is modeled with the Lodestar SOLT (“SOL Turbulence”) code. Specifically, the implications for the SOL heat flux width of experimentally observed, Li-induced changes in the pedestal profiles are considered. The SOLT code used in the modeling has been expanded recently to include ion temperature evolution and ion diamagnetic drift effects. This work focuses on two NSTX discharges occurring pre- and with-Li deposition. The simulation density and temperature profiles are constrained, inside the last closed flux surface only, to match those measured inmore » the two experiments, and the resulting drift-interchange-driven turbulence is explored. The effect of Li enters the simulation only through the pedestal profile constraint: Li modifies the experimental density and temperature profiles in the pedestal, and these profiles affect the simulated SOL turbulence. The power entering the SOL measured in the experiments is matched in the simulations by adjusting “free” dissipation parameters (e.g., diffusion coefficients) that are not measured directly in the experiments. With power-matching, (a) the heat flux SOL width is smaller, as observed experimentally by infra-red thermography, and (b) the simulated density fluctuation amplitudes are reduced with Li, as inferred for the experiments as well from reflectometry analysis. The instabilities and saturation mechanisms that underlie the SOLT model equilibria are also discussed.« less

  9. Modeling and experiments for the time-dependent diffusion coefficient during methane desorption from coal

    NASA Astrophysics Data System (ADS)

    Cheng-Wu, Li; Hong-Lai, Xue; Cheng, Guan; Wen-biao, Liu

    2018-04-01

    Statistical analysis shows that in the coal matrix, the diffusion coefficient for methane is time-varying, and its integral satisfies the formula μt κ /(1 + β κ ). Therefore, a so-called dynamic diffusion coefficient model (DDC model) is developed. To verify the suitability and accuracy of the DDC model, a series of gas diffusion experiments were conducted using coal particles of different sizes. The results show that the experimental data can be accurately described by the DDC and bidisperse models, but the fit to the DDC model is slightly better. For all coal samples, as time increases, the effective diffusion coefficient first shows a sudden drop, followed by a gradual decrease before stabilizing at longer times. The effective diffusion coefficient has a negative relationship with the size of the coal particle. Finally, the relationship between the constants of the DDC model and the effective diffusion coefficient is discussed. The constant α (μ/R 2 ) denotes the effective coefficient at the initial time, and the constants κ and β control the attenuation characteristic of the effective diffusion coefficient.

  10. Heterogeneity effects in visual search predicted from the group scanning model.

    PubMed

    Macquistan, A D

    1994-12-01

    The group scanning model of feature integration theory (Treisman & Gormican, 1988) suggests that subjects search visual displays serially by groups, but process items within each group in parallel. The size of these groups is determined by the discriminability of the targets in the background of distractors. When the target is poorly discriminable, the size of the scanned group will be small, and search will be slow. The model predicts that group size will be smallest when targets of an intermediate value on a perceptual dimension are presented in a heterogeneous background of distractors that have higher and lower values on the same dimension. Experiment 1 demonstrates this effect. Experiment 2 controls for a possible confound of decision complexity in Experiment 1. For simple feature targets, the group scanning model provides a good account of the visual search process.

  11. The role of visual imagery in the retention of information from sentences.

    PubMed

    Drose, G S; Allen, G L

    1994-01-01

    We conducted two experiments to evaluate a multiple-code model for sentence memory that posits both propositional and visual representational systems. Both sentences involved recognition memory. The results of Experiment 1 indicated that subjects' recognition memory for concrete sentences was superior to their recognition memory for abstract sentences. Instructions to use visual imagery to enhance recognition performance yielded no effects. Experiment 2 tested the prediction that interference by a visual task would differentially affect recognition memory for concrete sentences. Results showed the interference task to have had a detrimental effect on recognition memory for both concrete and abstract sentences. Overall, the evidence provided partial support for both a multiple-code model and a semantic integration model of sentence memory.

  12. Macroscopic quantum tunneling escape of Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Zhao, Xinxin; Alcala, Diego A.; McLain, Marie A.; Maeda, Kenji; Potnis, Shreyas; Ramos, Ramon; Steinberg, Aephraim M.; Carr, Lincoln D.

    2017-12-01

    Recent experiments on macroscopic quantum tunneling reveal a nonexponential decay of the number of atoms trapped in a quasibound state behind a potential barrier. Through both experiment and theory, we demonstrate this nonexponential decay results from interactions between atoms. Quantum tunneling of tens of thousands of 87Rb atoms in a Bose-Einstein condensate is modeled by a modified Jeffreys-Wentzel-Kramers-Brillouin model, taking into account the effective time-dependent barrier induced by the mean field. Three-dimensional Gross-Pitaevskii simulations corroborate a mean-field result when compared with experiments. However, with one-dimensional modeling using time-evolving block decimation, we present an effective renormalized mean-field theory that suggests many-body dynamics for which a bare mean-field theory may not apply.

  13. General Blending Models for Data From Mixture Experiments

    PubMed Central

    Brown, L.; Donev, A. N.; Bissett, A. C.

    2015-01-01

    We propose a new class of models providing a powerful unification and extension of existing statistical methodology for analysis of data obtained in mixture experiments. These models, which integrate models proposed by Scheffé and Becker, extend considerably the range of mixture component effects that may be described. They become complex when the studied phenomenon requires it, but remain simple whenever possible. This article has supplementary material online. PMID:26681812

  14. Evaluation of an imputed pitch velocity model of the auditory tau effect.

    PubMed

    Henry, Molly J; McAuley, J Devin; Zaleha, Marta

    2009-08-01

    This article extends an imputed pitch velocity model of the auditory kappa effect proposed by Henry and McAuley (2009a) to the auditory tau effect. Two experiments were conducted using an AXB design in which listeners judged the relative pitch of a middle target tone (X) in ascending and descending three-tone sequences. In Experiment 1, sequences were isochronous, establishing constant fast, medium, and slow velocity conditions. No systematic distortions in perceived target pitch were observed, and thresholds were similar across velocity conditions. Experiment 2 introduced to-be-ignored variations in target timing. Variations in target timing that deviated from constant velocity conditions introduced systematic distortions in perceived target pitch, indicative of a robust auditory tau effect. Consistent with an auditory motion hypothesis, the magnitude of the tau effect was larger at faster velocities. In addition, the tau effect was generally stronger for descending sequences than for ascending sequences. Combined with previous work on the auditory kappa effect, the imputed velocity model and associated auditory motion hypothesis provide a unified quantitative account of both auditory tau and kappa effects. In broader terms, these findings add support to the view that pitch and time relations in auditory patterns are fundamentally interdependent.

  15. Assessing the Combined Antibacterial Effect of Isoniazid and Rifampin on Four Mycobacterium tuberculosis Strains Using In Vitro Experiments and Response-Surface Modeling

    PubMed Central

    2017-01-01

    ABSTRACT While isoniazid and rifampin have been the cornerstone of tuberculosis therapy caused by drug-susceptible Mycobacterium tuberculosis for more than 40 years, their combined action has never been thoroughly assessed by modern quantitative pharmacology approaches. The aims of this work were to perform in vitro experiments and mathematical modeling of the antibacterial effect of isoniazid and rifampin alone and in combination against various strains of Mycobacterium tuberculosis. After MIC determination of H37Rv and three strains belonging to the Beijing, Euro-American, and Indo-Oceanic lineages, the antibacterial effects of isoniazid and rifampin alone and in combination were studied in static time-kill experiments. A sigmoidal maximum effect model (Hill equation) and a response-surface model were used to describe the effect of the drugs alone and in combination, respectively. The killing effect of isoniazid and rifampin alone were well described by the Hill equation. Rifampin displayed a more concentration-dependent effect than isoniazid around the MIC. The pharmacodynamics parameters of each drug (maximal effect, median effect concentration, and coefficient of sigmoidicity) were quite similar between the four strains. The response-surface model from Minto et al. fit data of combined effect very well with low bias and imprecision (C. F. Minto, T. W. Schnider, T. G. Short, K. M. Gregg, A. Gentilini, Anesthesiology 92:1603–1616, 2000, https://doi.org/10.1097/00000542-200006000-00017). Response-surface modeling showed that the combined action of isoniazid and rifampin was synergistic for the H37Rv, Beijing, and Euro-American strains but only additive for the Indo-Oceanic strain. This study can serve as a motivating example for preclinical evaluation of combined action of antituberculous drugs. PMID:29061753

  16. Numerical Modeling of Complex Targets for High-Energy- Density Experiments with Ion Beams and other Drivers

    DOE PAGES

    Koniges, Alice; Liu, Wangyi; Lidia, Steven; ...

    2016-04-01

    We explore the simulation challenges and requirements for experiments planned on facilities such as the NDCX-II ion accelerator at LBNL, currently undergoing commissioning. Hydrodynamic modeling of NDCX-II experiments include certain lower temperature effects, e.g., surface tension and target fragmentation, that are not generally present in extreme high-energy laser facility experiments, where targets are completely vaporized in an extremely short period of time. Target designs proposed for NDCX-II range from metal foils of order one micron thick (thin targets) to metallic foam targets several tens of microns thick (thick targets). These high-energy-density experiments allow for the study of fracture as wellmore » as the process of bubble and droplet formation. We incorporate these physics effects into a code called ALE-AMR that uses a combination of Arbitrary Lagrangian Eulerian hydrodynamics and Adaptive Mesh Refinement. Inclusion of certain effects becomes tricky as we must deal with non-orthogonal meshes of various levels of refinement in three dimensions. A surface tension model used for droplet dynamics is implemented in ALE-AMR using curvature calculated from volume fractions. Thick foam target experiments provide information on how ion beam induced shock waves couple into kinetic energy of fluid flow. Although NDCX-II is not fully commissioned, experiments are being conducted that explore material defect production and dynamics.« less

  17. Mediated Effects of Technology Competencies and Experiences on Relations among Attitudes Towards Technology Use, Technology Ownership, and Self Efficacy about Technological Pedagogical Content Knowledge

    NASA Astrophysics Data System (ADS)

    Yerdelen-Damar, Sevda; Boz, Yezdan; Aydın-Günbatar, Sevgi

    2017-08-01

    This study examined the relations of preservice science teachers' attitudes towards technology use, technology ownership, technology competencies, and experiences to their self-efficacy beliefs about technological pedagogical content knowledge (TPACK). The present study also investigated interrelations among preservice teachers' attitudes towards technology use, technology ownership, technology competencies, and experiences. The participants of study were 665 elementary preservice science teachers (467 females, 198 males) from 7 colleges in Turkey. The proposed model based on educational technology literature was tested using structural equation modeling. The model testing results revealed that preservice teachers' technology competencies and experiences mediated the relation of technology ownership to their TPACK self efficacy beliefs. The direct relation of their possession of technology to their TPACK self efficacy beliefs was insignificant while the indirect relation through their technology competencies and experiences was significant. The results also indicated there were significant direct effects of preservice teachers' attitudes towards technology use, technology competencies, and experiences on their TPACK self efficacy beliefs.

  18. A comparative study of behaviors of ventilated supercavities between experimental models with different mounting configurations

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Jae; Kawakami, Ellison; Karn, Ashish; Arndt, Roger E. A.

    2016-08-01

    Small-scale water tunnel experiments of the phenomenon of supercavitation can be carried out broadly using two different kinds of experimental models-in the first model (forward facing model, or FFM), the incoming flow first interacts with the cavitator at front, which is connected to the strut through a ventilation pipe. The second model could have the strut and the ventilation pipe preceding the cavitator (backward facing model, or BFM). This is the continuation of a water tunnel study of the effects of unsteady flows on axisymmetric supercavities. In this study, the unwanted effect of test model configuration on supercavity shape in periodic flows was explored through a comparison of FFM and BFM models. In our experiments, it was found that periodic gust flows have only a minimal effect on the maximum diameter and the cavity length can be shortened above a certain vertical velocity of periodic flows. These findings appear to be robust regardless of the model configuration.

  19. The Generalized Quantum Episodic Memory Model.

    PubMed

    Trueblood, Jennifer S; Hemmer, Pernille

    2017-11-01

    Recent evidence suggests that experienced events are often mapped to too many episodic states, including those that are logically or experimentally incompatible with one another. For example, episodic over-distribution patterns show that the probability of accepting an item under different mutually exclusive conditions violates the disjunction rule. A related example, called subadditivity, occurs when the probability of accepting an item under mutually exclusive and exhaustive instruction conditions sums to a number >1. Both the over-distribution effect and subadditivity have been widely observed in item and source-memory paradigms. These phenomena are difficult to explain using standard memory frameworks, such as signal-detection theory. A dual-trace model called the over-distribution (OD) model (Brainerd & Reyna, 2008) can explain the episodic over-distribution effect, but not subadditivity. Our goal is to develop a model that can explain both effects. In this paper, we propose the Generalized Quantum Episodic Memory (GQEM) model, which extends the Quantum Episodic Memory (QEM) model developed by Brainerd, Wang, and Reyna (2013). We test GQEM by comparing it to the OD model using data from a novel item-memory experiment and a previously published source-memory experiment (Kellen, Singmann, & Klauer, 2014) examining the over-distribution effect. Using the best-fit parameters from the over-distribution experiments, we conclude by showing that the GQEM model can also account for subadditivity. Overall these results add to a growing body of evidence suggesting that quantum probability theory is a valuable tool in modeling recognition memory. Copyright © 2016 Cognitive Science Society, Inc.

  20. Testing Two Path Models to Explore Relationships between Students' Experiences of the Teaching-Learning Environment, Approaches to Learning and Academic Achievement

    ERIC Educational Resources Information Center

    Karagiannopoulou, Evangelia; Milienos, Fotios S.

    2015-01-01

    The study explores the relationships between students' experiences of the teaching-learning environment and their approaches to learning, and the effects of these variables on academic achievement. Two three-stage models were tested with structural equation modelling techniques. The "Approaches and Study Skills Inventory for Students"…

  1. Host Model Uncertainty in Aerosol Radiative Effects: the AeroCom Prescribed Experiment and Beyond

    NASA Astrophysics Data System (ADS)

    Stier, Philip; Schutgens, Nick; Bian, Huisheng; Boucher, Olivier; Chin, Mian; Ghan, Steven; Huneeus, Nicolas; Kinne, Stefan; Lin, Guangxing; Myhre, Gunnar; Penner, Joyce; Randles, Cynthia; Samset, Bjorn; Schulz, Michael; Yu, Hongbin; Zhou, Cheng; Bellouin, Nicolas; Ma, Xiaoyan; Yu, Fangqun; Takemura, Toshihiko

    2013-04-01

    Anthropogenic and natural aerosol radiative effects are recognized to affect global and regional climate. Multi-model "diversity" in estimates of the aerosol radiative effect is often perceived as a measure of the uncertainty in modelling aerosol itself. However, current aerosol models vary considerably in model components relevant for the calculation of aerosol radiative forcings and feedbacks and the associated "host-model uncertainties" are generally convoluted with the actual uncertainty in aerosol modelling. In the AeroCom Prescribed intercomparison study we systematically isolate and quantify host model uncertainties on aerosol forcing experiments through prescription of identical aerosol radiative properties in eleven participating models. Host model errors in aerosol radiative forcing are largest in regions of uncertain host model components, such as stratocumulus cloud decks or areas with poorly constrained surface albedos, such as sea ice. Our results demonstrate that host model uncertainties are an important component of aerosol forcing uncertainty that require further attention. However, uncertainties in aerosol radiative effects also include short-term and long-term feedback processes that will be systematically explored in future intercomparison studies. Here we will present an overview of the proposals for discussion and results from early scoping studies.

  2. Dicke-model simulation via cavity-assisted Raman transitions

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiqiang; Lee, Chern Hui; Kumar, Ravi; Arnold, K. J.; Masson, Stuart J.; Grimsmo, A. L.; Parkins, A. S.; Barrett, M. D.

    2018-04-01

    The Dicke model is of fundamental importance in quantum mechanics for understanding the collective behavior of atoms coupled to a single electromagnetic mode. Here, we demonstrate a Dicke-model simulation via cavity-assisted Raman transitions in a configuration using counterpropagating laser beams. The observations indicate that motional effects should be included to fully account for the results. These results are contrary to experiments using single-beam and copropagating configurations. We give a theoretical description that accounts for the beam geometries used in the experiments and indicates the potential role of motional effects. In particular, a model is given that highlights the influence of Doppler broadening on the observed phase-transition thresholds.

  3. Geometry and mass model of ionizing radiation experiments on the LDEF satellite

    NASA Technical Reports Server (NTRS)

    Colborn, B. L.; Armstrong, T. W.

    1992-01-01

    Extensive measurements related to ionizing radiation environments and effects were made on the LDEF satellite during its mission lifetime of almost 6 years. These data, together with the opportunity they provide for evaluating predictive models and analysis methods, should allow more accurate assessments of the space radiation environment and related effects for future missions in low Earth orbit. The LDEF radiation dosimetry data is influenced to varying degrees by material shielding effects due to the dosimeter itself, nearby components and experiments, and the spacecraft structure. A geometry and mass model is generated of LDEF, incorporating sufficient detail that it can be applied in determining the influence of material shielding on ionizing radiation measurements and predictions. This model can be used as an aid in data interpretation by unfolding shielding effects from the LDEF radiation dosimeter responses. Use of the LDEF geometry/mass model, in conjunction with predictions and comparisons with LDEF dosimetry data currently underway, will also allow more definitive evaluations of current radiation models for future mission applications.

  4. Modeling of Dense Plasma Effects in Short-Pulse Laser Experiments

    NASA Astrophysics Data System (ADS)

    Walton, Timothy; Golovkin, Igor; Macfarlane, Joseph; Prism Computational Sciences, Madison, WI Team

    2016-10-01

    Warm and Hot Dense Matter produced in short-pulse laser experiments can be studied with new high resolving power x-ray spectrometers. Data interpretation implies accurate modeling of the early-time heating dynamics and the radiation conditions that are generated. Producing synthetic spectra requires a model that describes the major physical processes that occur inside the target, including the hot-electron generation and relaxation phases and the effect of target heating. An important issue concerns the sensitivity of the predicted K-line shifts to the continuum lowering model that is used. We will present a set of PrismSPECT spectroscopic simulations using various continuum lowering models: Hummer/Mihalas, Stewart-Pyatt, and Ecker-Kroll and discuss their effect on the formation of K-shell features. We will also discuss recently implemented models for dense plasma shifts for H-like, He-like and neutral systems.

  5. 'Chain pooling' model selection as developed for the statistical analysis of a rotor burst protection experiment

    NASA Technical Reports Server (NTRS)

    Holms, A. G.

    1977-01-01

    A statistical decision procedure called chain pooling had been developed for model selection in fitting the results of a two-level fixed-effects full or fractional factorial experiment not having replication. The basic strategy included the use of one nominal level of significance for a preliminary test and a second nominal level of significance for the final test. The subject has been reexamined from the point of view of using as many as three successive statistical model deletion procedures in fitting the results of a single experiment. The investigation consisted of random number studies intended to simulate the results of a proposed aircraft turbine-engine rotor-burst-protection experiment. As a conservative approach, population model coefficients were chosen to represent a saturated 2 to the 4th power experiment with a distribution of parameter values unfavorable to the decision procedures. Three model selection strategies were developed.

  6. Generality of a congruity effect in judgements of relative order.

    PubMed

    Liu, Yang S; Chan, Michelle; Caplan, Jeremy B

    2014-10-01

    The judgement of relative order (JOR) procedure is used to investigate serial-order memory. Measuring response times, the wording of the instructions (whether the earlier or the later item was designated as the target) reversed the direction of search in subspan lists (Chan, Ross, Earle, & Caplan Psychonomic Bulletin & Review, 16(5), 945-951, 2009). If a similar congruity effect applied to above-span lists and, furthermore, with error rate as the measure, this could suggest how to model order memory across scales. Participants performed JORs on lists of nouns (Experiment 1: list lengths = 4, 6, 8, 10) or consonants (Experiment 2: list lengths = 4, 8). In addition to the usual distance, primacy, and recency effects, instructions interacted with serial position of the later probe in both experiments, not only in response time, but also in error rate, suggesting that availability, not just accessibility, is affected by instructions. The congruity effect challenges current memory models. We fitted Hacker's (Journal of Experimental Psychology: Human Learning and Memory, 6(6), 651-675, 1980) self-terminating search model to our data and found that a switch in search direction could explain the congruity effect for short lists, but not longer lists. This suggests that JORs may need to be understood via direct-access models, adapted to produce a congruity effect, or a mix of mechanisms.

  7. Normative and descriptive accounts of the influence of power and contingency on causal judgement.

    PubMed

    Perales, José C; Shanks, David R

    2003-08-01

    The power PC theory (Cheng, 1997) is a normative account of causal inference, which predicts that causal judgements are based on the power p of a potential cause, where p is the cause-effect contingency normalized by the base rate of the effect. In three experiments we demonstrate that both cause-effect contingency and effect base-rate independently affect estimates in causal learning tasks. In Experiment 1, causal strength judgements were directly related to power p in a task in which the effect base-rate was manipulated across two positive and two negative contingency conditions. In Experiments 2 and 3 contingency manipulations affected causal estimates in several situations in which power p was held constant, contrary to the power PC theory's predictions. This latter effect cannot be explained by participants' conflation of reliability and causal strength, as Experiment 3 demonstrated independence of causal judgements and confidence. From a descriptive point of view, the data are compatible with Pearce's (1987) model, as well as with several other judgement rules, but not with the Rescorla-Wagner (Rescorla & Wagner, 1972) or power PC models.

  8. Experiments And Model Development For The Investigation Of Sooting And Radiation Effects In Microgravity Droplet Combustion

    NASA Technical Reports Server (NTRS)

    Yozgatligil, Ahmet; Choi, Mun Young; Dryer, Frederick L.; Kazakov, Andrei; Dobashi, Ritsu

    2003-01-01

    This study involves flight experiments (for droplets between 1.5 to 5 mm) and supportive ground-based experiments, with concurrent numerical model development and validation. The experiments involve two fuels: n-heptane, and ethanol. The diagnostic measurements include light extinction for soot volume fraction, two-wavelength pyrometry and thin-filament pyrometry for temperature, spectral detection for OH chemiluminescence, broadband radiometry for flame emission, and thermophoretic sampling with subsequent transmission electron microscopy for soot aerosol property calculations.

  9. Computer modeling of the stalled flow of a rotating cylinder and the reverse magnus effect

    NASA Astrophysics Data System (ADS)

    Belotserkovskii, S. M.; Kotovskii, V. N.; Nisht, M. I.; Fedorov, R. M.

    1985-02-01

    Unsteady stalled flow around a rotating cylinder is investigated in a numerical experiment. Attention is mostly given to the reverse Magnus effect which was discovered in tube experiments at some critical rotational speed of the cylinder.

  10. Developing an approach to effectively use super ensemble experiments for the projection of hydrological extremes under climate change

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Kim, H.; Utsumi, N.

    2017-12-01

    This study aims to develop a new approach which projects hydrology under climate change using super ensemble experiments. The use of multiple ensemble is essential for the estimation of extreme, which is a major issue in the impact assessment of climate change. Hence, the super ensemble experiments are recently conducted by some research programs. While it is necessary to use multiple ensemble, the multiple calculations of hydrological simulation for each output of ensemble simulations needs considerable calculation costs. To effectively use the super ensemble experiments, we adopt a strategy to use runoff projected by climate models directly. The general approach of hydrological projection is to conduct hydrological model simulations which include land-surface and river routing process using atmospheric boundary conditions projected by climate models as inputs. This study, on the other hand, simulates only river routing model using runoff projected by climate models. In general, the climate model output is systematically biased so that a preprocessing which corrects such bias is necessary for impact assessments. Various bias correction methods have been proposed, but, to the best of our knowledge, no method has proposed for variables other than surface meteorology. Here, we newly propose a method for utilizing the projected future runoff directly. The developed method estimates and corrects the bias based on the pseudo-observation which is a result of retrospective offline simulation. We show an application of this approach to the super ensemble experiments conducted under the program of Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI). More than 400 ensemble experiments from multiple climate models are available. The results of the validation using historical simulations by HAPPI indicates that the output of this approach can effectively reproduce retrospective runoff variability. Likewise, the bias of runoff from super ensemble climate projections is corrected, and the impact of climate change on hydrologic extremes is assessed in a cost-efficient way.

  11. Making things difficult in lexical decision: the impact of pseudohomophones and transposed-letter nonwords on frequency and semantic priming effects.

    PubMed

    Lupker, Stephen J; Pexman, Penny M

    2010-09-01

    Performance in a lexical decision task is crucially dependent on the difficulty of the word-nonword discrimination. More wordlike nonwords cause not only a latency increase for words but also, as reported by Stone and Van Orden (1993), larger word frequency effects. Several current models of lexical decision making can explain these types of results in terms of a single mechanism, a mechanism driven by the nature of the interactions within the lexicon. In 2 experiments, we replicated Stone and Van Orden's increased frequency effect using both pseudohomophones (e.g., BEEST) and transposed-letter nonwords (e.g., JUGDE) as the more wordlike nonwords. In a 3rd experiment, we demonstrated that simply increasing word latencies without changing the difficulty of the word-nonword discrimination does not produce larger frequency effects. These results are reasonably consistent with many current models. In contrast, neither pseudohomophones nor transposed-letter nonwords altered the size of semantic priming effects across 4 additional experiments, posing a challenge to models that would attempt to explain both nonword difficulty effects and semantic priming effects in lexical decision tasks in terms of a single, lexically driven mechanism. (c) 2010 APA, all rights reserved).

  12. Sandbox Tectonics As A Teaching Tool

    NASA Astrophysics Data System (ADS)

    Delaughter, J.

    2005-12-01

    Students are typically introduced to the relative motions of plates and its effects either through text-based descriptions, paper models, or both. However, though students may learn to repeat the description of the effects, many students still do not show a deeper understanding of the process, as shown by examinations of students before and after an introductory geology course (DeLaughter et al, 1998). This is because students are rarely affected by the information on a visceral level; because their preconceptions are never challenged, they never internalize the information as part of their model of how the world works. However, when concepts such as plate motions and their effects are presented to students as part of a tangible, physical experiment, the ideas can have a much greater impact (Carey et al, 1989). The students use the new information to build more complete mental models while learning that such models can and must change in response to new information (Herbert, 2003). When such experiments are performed in a geology class, they afford the students a direct and visceral experience that may enhance the learning process. In this exercise for middle school students, the effects of relative plate motions on overlying sediments are modeled through a simple and inexpensive set of experiments using sand and newspaper. These experiments provide qualitatively the same results as those performed by geologists researching various aspects of faulting and folding (e.g., Horsfield, 1977, Domingez et al., 2000). A secondary benefit of these experiments is that when the students do not pull the papers perfectly the combination of effects can mimic real terrains (e.g., transpressional) very closely. This intrusion of methodological errors can also lead to a lively discussion of how science is done and what the results of an experiment imply, thereby providing a pedagogical benefit as well. Thus students can be shown the effects of relative plate motions in a direct and obvious manner. Because the experiments produce tangible results, the students experience them on a more visceral level and may be able to incorporate the concepts better than they would through a description or computer simulation of the effects (Klosko et al., 2000). And, as the equipment used is very inexpensive, the experiment is well within the means of almost any school system. References Carey, S., R. Evans, M. Honda, E. Jay, C. Unger, 1989, ``An experiment is when you try it and see if it works'': A study of grade 7 students' understanding of the construction of knowledge, International Journal of Science Education, 11, 514-529 DeLaughter, J., S. Stein, C. Stein, K. R. Bain, 1998, Preconceptions abound among students in an introductory earth science course, EOS, 79, 429+432 Dominguez, S, J. Malavieille, S. Lallemand, 2000, Deformation of accretionary wedges in response to seamount subduction: Insights from sandbox experiments, Tectonics, 19(1), 182-196 Herbert, B., 2003, The role of scaffolding student metacognition in developing mental models of complex, Earth and environmental systems. DFG-NSF International Workshops on Research and Development in Mathematics and Science Education, November 19-21, 2003, Washington D.C. http://geoexplorer.tamu.edu/dfgnsf/WG1.html Horsfield, W.T., 1977, An experimental approach to basement controlled faulting, Geologie en Mijnbouw, 56, 363-370 Klosko, E., J. DeLaughter, S. Stein, 2000, Technology in introductory geophysics: the high - low mix, Computers & Geosciences, 26(6), 693-698

  13. Framing From Experience: Cognitive Processes and Predictions of Risky Choice.

    PubMed

    Gonzalez, Cleotilde; Mehlhorn, Katja

    2016-07-01

    A framing bias shows risk aversion in problems framed as "gains" and risk seeking in problems framed as "losses," even when these are objectively equivalent and probabilities and outcomes values are explicitly provided. We test this framing bias in situations where decision makers rely on their own experience, sampling the problem's options (safe and risky) and seeing the outcomes before making a choice. In Experiment 1, we replicate the framing bias in description-based decisions and find risk indifference in gains and losses in experience-based decisions. Predictions of an Instance-Based Learning model suggest that objective probabilities as well as the number of samples taken are factors that contribute to the lack of framing effect. We test these two factors in Experiment 2 and find no framing effect when a few samples are taken but when large samples are taken, the framing effect appears regardless of the objective probability values. Implications of behavioral results and cognitive modeling are discussed. Copyright © 2015 Cognitive Science Society, Inc.

  14. Reputation Effects in Social Networks Do Not Promote Cooperation: An Experimental Test of the Raub & Weesie Model.

    PubMed

    Corten, Rense; Rosenkranz, Stephanie; Buskens, Vincent; Cook, Karen S

    2016-01-01

    Despite the popularity of the notion that social cohesion in the form of dense social networks promotes cooperation in Prisoner's Dilemmas through reputation, very little experimental evidence for this claim exists. We address this issue by testing hypotheses from one of the few rigorous game-theoretic models on this topic, the Raub & Weesie model, in two incentivized lab experiments. In the experiments, 156 subjects played repeated two-person PDs in groups of six. In the "atomized interactions" condition, subjects were only informed about the outcomes of their own interactions, while in the "embedded" condition, subjects were informed about the outcomes of all interactions in their group, allowing for reputation effects. The design of the experiments followed the specification of the RW model as closely as possible. For those aspects of the model that had to be modified to allow practical implementation in an experiment, we present additional analyses that show that these modifications do not affect the predictions. Contrary to expectations, we do not find that cooperation is higher in the embedded condition than in the atomized interaction. Instead, our results are consistent with an interpretation of the RW model that includes random noise, or with learning models of cooperation in networks.

  15. Reputation Effects in Social Networks Do Not Promote Cooperation: An Experimental Test of the Raub & Weesie Model

    PubMed Central

    Corten, Rense; Rosenkranz, Stephanie; Buskens, Vincent; Cook, Karen S.

    2016-01-01

    Despite the popularity of the notion that social cohesion in the form of dense social networks promotes cooperation in Prisoner’s Dilemmas through reputation, very little experimental evidence for this claim exists. We address this issue by testing hypotheses from one of the few rigorous game-theoretic models on this topic, the Raub & Weesie model, in two incentivized lab experiments. In the experiments, 156 subjects played repeated two-person PDs in groups of six. In the “atomized interactions” condition, subjects were only informed about the outcomes of their own interactions, while in the “embedded” condition, subjects were informed about the outcomes of all interactions in their group, allowing for reputation effects. The design of the experiments followed the specification of the RW model as closely as possible. For those aspects of the model that had to be modified to allow practical implementation in an experiment, we present additional analyses that show that these modifications do not affect the predictions. Contrary to expectations, we do not find that cooperation is higher in the embedded condition than in the atomized interaction. Instead, our results are consistent with an interpretation of the RW model that includes random noise, or with learning models of cooperation in networks. PMID:27366907

  16. Individual differences in transcranial electrical stimulation current density

    PubMed Central

    Russell, Michael J; Goodman, Theodore; Pierson, Ronald; Shepherd, Shane; Wang, Qiang; Groshong, Bennett; Wiley, David F

    2013-01-01

    Transcranial electrical stimulation (TCES) is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject's head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging (MRI) data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individual differences were greatest near the electrodes (ten-fold differences were common), but simulated current was found in all regions of the brain. Sites that were distant from the electrodes (e.g. hypothalamus) typically showed two-fold individual differences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI-based modeling should be considered in place of the 10-20 system when accurate TCES is needed. PMID:24285948

  17. Understanding Coupled Earth-Surface Processes through Experiments and Models (Invited)

    NASA Astrophysics Data System (ADS)

    Overeem, I.; Kim, W.

    2013-12-01

    Traditionally, both numerical models and experiments have been purposefully designed to ';isolate' singular components or certain processes of a larger mountain to deep-ocean interconnected source-to-sink (S2S) transport system. Controlling factors driven by processes outside of the domain of immediate interest were treated and simplified as input or as boundary conditions. Increasingly, earth surface processes scientists appreciate feedbacks and explore these feedbacks with more dynamically coupled approaches to their experiments and models. Here, we discuss key concepts and recent advances made in coupled modeling and experimental setups. In addition, we emphasize challenges and new frontiers to coupled experiments. Experiments have highlighted the important role of self-organization; river and delta systems do not always need to be forced by external processes to change or develop characteristic morphologies. Similarly modeling f.e. has shown that intricate networks in tidal deltas are stable because of the interplay between river avulsions and the tidal current scouring with both processes being important to develop and maintain the dentritic networks. Both models and experiment have demonstrated that seemingly stable systems can be perturbed slightly and show dramatic responses. Source-to-sink models were developed for both the Fly River System in Papua New Guinea and the Waipaoa River in New Zealand. These models pointed to the importance of upstream-downstream effects and enforced our view of the S2S system as a signal transfer and dampening conveyor belt. Coupled modeling showed that deforestation had extreme effects on sediment fluxes draining from the catchment of the Waipaoa River in New Zealand, and that this increase in sediment production rapidly shifted the locus of offshore deposition. The challenge in designing coupled models and experiments is both technological as well as intellectual. Our community advances to make numerical model coupling more straightforward through common interfaces and standardization of time-stepping, model domains and model parameters. At the same time major steps forward require an interdisciplinary approach, wherein the source to sink system contains ecological feedbacks and human actors.

  18. Race of source effects in the elaboration likelihood model.

    PubMed

    White, P H; Harkins, S G

    1994-11-01

    In a series of experiments, we investigated the effect of race of source on persuasive communications in the Elaboration Likelihood Model (R.E. Petty & J.T. Cacioppo, 1981, 1986). In Experiment 1, we found no evidence that White participants responded to a Black source as a simple negative cue. Experiment 2 suggested the possibility that exposure to a Black source led to low-involvement message processing. In Experiments 3 and 4, a distraction paradigm was used to test this possibility, and it was found that participants under low involvement were highly motivated to process a message presented by a Black source. In Experiment 5, we found that attitudes toward the source's ethnic group, rather than violations of expectancies, accounted for this processing effect. Taken together, the results of these experiments are consistent with S.L. Gaertner and J.F. Dovidio's (1986) theory of aversive racism, which suggests that Whites, because of a combination of egalitarian values and underlying negative racial attitudes, are very concerned about not appearing unfavorable toward Blacks, leading them to be highly motivated to process messages presented by a source from this group.

  19. Modeling the Effect of Enlarging Seating Room on Passengers' Preference of Taiwan's Domestic Airlines

    NASA Technical Reports Server (NTRS)

    Lu, Jin-Long; Tsai, Li-Non

    2003-01-01

    This study addresses the need for measuring the effect of enlarging seating room in airplane on passengers' preferences of airline in Taiwan. The results can assist Taiwan's domestic air carriers in better understanding their customers' expectations. Stated choice experiment is used to incorporate passengers' trade-offs in the preferred measurement, and three major attributes are taken into account in the stated choice experiment: (1) type of seat (enlarged or not), (2) price, and (3) brand names of airlines. Furthermore, a binary logit model is used to model the choice behavior of air passengers. The findings show that the type of seat is a major significant variable; price and airline's brand are also significant as well. It concludes that air carriers should put more emphasis on the issue of improving the quality of seat comfort. Keywords: Passengers' preference, Enlarged seating room, Stated choice experiment, Binary logit model.

  20. Toddlers' imitative learning in interactive and observational contexts: the role of age and familiarity of the model.

    PubMed

    Shimpi, Priya M; Akhtar, Nameera; Moore, Chris

    2013-10-01

    Three experiments examined the effects of age and familiarity of a model on toddlers' imitative learning in observational contexts (Experiments 1, 2, and 3) and interactive contexts (Experiments 2 and 3). Experiment 1 (N=112 18-month-old toddlers) varied the age (child vs. adult) and long-term familiarity (kin vs. stranger) of the person who modeled the novel actions. Experiment 2 (N=48 18-month-olds and 48 24-month-olds) and Experiment 3 (N=48 24-month-olds) varied short-term familiarity with the model (some or none) and learning context (interactive or observational). The most striking findings were that toddlers were able to learn a new action from observing completely unfamiliar strangers who did not address them and were far less likely to imitate an unfamiliar model who directly interacted with them. These studies highlight the robustness of toddlers' observational learning and reveal limitations of learning from unfamiliar models in interactive contexts. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Visual analysis of immiscible displacement processes in porous media under ultrasound effect

    NASA Astrophysics Data System (ADS)

    Naderi, Khosrow; Babadagli, Tayfun

    2011-05-01

    The effect of sonic waves, in particular, ultrasonic radiation, on immiscible displacement in porous media and enhanced oil recovery has been of interest for more than five decades. Attempts were made to investigate the effect through core scale experimental or theoretical models. Visual experiments are useful to scrutinize the reason for improved oil recovery under acoustic waves of different frequency but are not abundant in literature. In this paper, we report observations and analyses as to the effects of ultrasonic energy on immiscible displacement and interaction of the fluid matrix visually in porous media through two-dimensional (2D) sand pack experiments. 2D glass bead models with different wettabilities were saturated with different viscosity oils and water was injected into the models. The experiments were conducted with and without ultrasound. Dynamic water injection experiments were preferred as they had both viscous and capillary forces in effect. The displacement patterns were evaluated both in terms of their shape, size, and the interface characteristics quantitatively and qualitatively to account for the effects of ultrasonic waves on the displacement and the reason for increased oil production under this type of sonic wave. More compact clusters were observed when ultrasonic energy was present in water-wet systems. In the oil-wet cases, more oil was produced after breakthrough when ultrasound was applied and no compact clusters were formed in contrast to the water-wet cases.

  2. Statistical models for causation: what inferential leverage do they provide?

    PubMed

    Freedman, David A

    2006-12-01

    Experiments offer more reliable evidence on causation than observational studies, which is not to gainsay the contribution to knowledge from observation. Experiments should be analyzed as experiments, not as observational studies. A simple comparison of rates might be just the right tool, with little value added by "sophisticated" models. This article discusses current models for causation, as applied to experimental and observational data. The intention-to-treat principle and the effect of treatment on the treated will also be discussed. Flaws in per-protocol and treatment-received estimates will be demonstrated.

  3. Oxytocin increases the influence of public service advertisements.

    PubMed

    Lin, Pei-Ying; Grewal, Naomi Sparks; Morin, Christophe; Johnson, Walter D; Zak, Paul J

    2013-01-01

    This paper presents a neurophysiologic model of effective public service advertisements (PSAs) and reports two experiments that test the model. In Experiment 1, we show that after watching 16 PSAs participants who received oxytocin, compared to those given a placebo, donated to 57% more causes, donated 56% more money, and reported 17% greater concern for those in the ads. In Experiment 2, we measured adrenocorticotropin hormone (ACTH) and oxytocin levels in blood before and after participants watched a PSA. As predicted by the model, donations occurred when participants had increases in both ACTH and oxytocin. Our results indicate that PSAs with social content that cause OT release will be more effective than those that do not. Our results also explain why some individuals do not respond to PSAs.

  4. Oxytocin Increases the Influence of Public Service Advertisements

    PubMed Central

    Lin, Pei-Ying; Grewal, Naomi Sparks; Morin, Christophe; Johnson, Walter D.; Zak, Paul J.

    2013-01-01

    This paper presents a neurophysiologic model of effective public service advertisements (PSAs) and reports two experiments that test the model. In Experiment 1, we show that after watching 16 PSAs participants who received oxytocin, compared to those given a placebo, donated to 57% more causes, donated 56% more money, and reported 17% greater concern for those in the ads. In Experiment 2, we measured adrenocorticotropin hormone (ACTH) and oxytocin levels in blood before and after participants watched a PSA. As predicted by the model, donations occurred when participants had increases in both ACTH and oxytocin. Our results indicate that PSAs with social content that cause OT release will be more effective than those that do not. Our results also explain why some individuals do not respond to PSAs. PMID:23460821

  5. Short- and Mid-Term Effects of Violent Victimization on Delinquency: A Multilevel Growth-Curve Modeling Approach.

    PubMed

    Kim, Young S; Lo, Celia C

    2016-10-01

    The present study investigates how adolescents' experiences of violent victimization exert short- and mid-term effects on their involvement in delinquency. The study compares and contrasts delinquency trajectories of youths whose experiences of violent victimization differ. A multilevel growth-curve modeling approach is applied to analyze data from five waves of the National Youth Survey. The results show that, although delinquency involvement increases as youths experience violent victimization, delinquency trajectories differ with the type of violent victimization, specifically, parental versus non-parental victimization. Violent victimization by parents produced a sharp initial decline in delinquency (short-term effect) followed by a rapid acceleration (mid-term effect). In turn, non-parental violence showed a stable trend over time. The findings have important implications for prevention and treatment services. © The Author(s) 2015.

  6. Enhanced Bulk-Edge Coulomb Coupling in Fractional Fabry-Perot Interferometers.

    PubMed

    von Keyserlingk, C W; Simon, S H; Rosenow, Bernd

    2015-09-18

    Recent experiments use Fabry-Perot (FP) interferometry to claim that the ν=5/2 quantum Hall state exhibits non-Abelian topological order. We note that the experiments appear inconsistent with a model neglecting bulk-edge Coulomb coupling and Majorana tunneling, so we reexamine the theory of FP devices. Even a moderate Coulomb coupling may strongly affect some fractional plateaus, but very weakly affect others, allowing us to model the data over a wide range of plateaus. While experiments are consistent with the ν=5/2 state harboring Moore-Read topological order, they may have measured Coulomb effects rather than an "even-odd effect" due to non-Abelian braiding.

  7. Iontophoretic transport of oligonucleotides across human epidermal membrane: a study of the Nernst-Planck model.

    PubMed

    Li, S K; Ghanem, A H; Teng, C L; Hardee, G E; Higuchi, W I

    2001-07-01

    The objective of this study was to investigate the transport behavior of a series of oligonucleotides with human epidermal membrane (HEM) and to examine the applicability of the modified NERNST-PLANCK model to transdermal iontophoresis of these macromolecules. Iontophoretic transport experiments were first carried out in a synthetic model membrane system (Nuclepore membranes) with a four-electrode potentiostat to examine the baseline modified NERNST-PLANCK model. The modified NERNST-PLANCK model derived from the Einstein relation and the Stokes-Einstein equation taken from previous work did not hold for the oligonucleotides. Results obtained in the Nuclepore studies were, however, consistent with predictions of the modified NERNST-PLANCK model using the experimentally determined electromobilities and diffusion coefficients. The electromobilities of the oligonucleotides (determined by capillary electrophoresis) were found to be more than a factor of two smaller than expected from the Einstein relation between electromobilities and diffusion coefficients (the latter determined in diffusion cell experiments). A correlation between these electromobilities and the theoretical electromobilities estimated by considering the effects of counterion binding and the effects of mobility reduction according to colloid theory was also observed. These results suggest that the modified NERNST-PLANCK model predictions are satisfactory only when the electromobilities and the effective molecular size of the oligonucleotides are known and are used directly to predict the iontophoretically enhanced transport. Results with the HEM experiments generally agreed with model predictions based on the experimental electromobilities. The oligonucleotide HEM flux data also suggest the existence of pores with effective pore radii greater than the effective radii estimated in previous studies with small molecular weight model permeants.

  8. A Longitudinal Quasi-Experiment on the Effects of Posttraining Transfer Interventions

    ERIC Educational Resources Information Center

    Gaudine, Alice P.; Saks, Alan M.

    2004-01-01

    A longitudinal quasi experiment tested the effects of a relapse prevention and transfer enhancement posttraining intervention on the self-efficacy, transfer behavior, and performance of a sample of nurses who attended a two-day training program on the McGill Model of Nursing. ANCOVA results failed to support the effectiveness of the intervention;…

  9. Appraisals Generate Specific Configurations of Facial Muscle Movements in a Gambling Task: Evidence for the Component Process Model of Emotion.

    PubMed

    Gentsch, Kornelia; Grandjean, Didier; Scherer, Klaus R

    2015-01-01

    Scherer's Component Process Model provides a theoretical framework for research on the production mechanism of emotion and facial emotional expression. The model predicts that appraisal results drive facial expressions, which unfold sequentially and cumulatively over time. In two experiments, we examined facial muscle activity changes (via facial electromyography recordings over the corrugator, cheek, and frontalis regions) in response to events in a gambling task. These events were experimentally manipulated feedback stimuli which presented simultaneous information directly affecting goal conduciveness (gambling outcome: win, loss, or break-even) and power appraisals (Experiment 1 and 2), as well as control appraisal (Experiment 2). We repeatedly found main effects of goal conduciveness (starting ~600 ms), and power appraisals (starting ~800 ms after feedback onset). Control appraisal main effects were inconclusive. Interaction effects of goal conduciveness and power appraisals were obtained in both experiments (Experiment 1: over the corrugator and cheek regions; Experiment 2: over the frontalis region) suggesting amplified goal conduciveness effects when power was high in contrast to invariant goal conduciveness effects when power was low. Also an interaction of goal conduciveness and control appraisals was found over the cheek region, showing differential goal conduciveness effects when control was high and invariant effects when control was low. These interaction effects suggest that the appraisal of having sufficient control or power affects facial responses towards gambling outcomes. The result pattern suggests that corrugator and frontalis regions are primarily related to cognitive operations that process motivational pertinence, whereas the cheek region would be more influenced by coping implications. Our results provide first evidence demonstrating that cognitive-evaluative mechanisms related to goal conduciveness, control, and power appraisals affect facial expressions dynamically over time, immediately after an event is perceived. In addition, our results provide further indications for the chronography of appraisal-driven facial movements and the underlying cognitive processes.

  10. Appraisals Generate Specific Configurations of Facial Muscle Movements in a Gambling Task: Evidence for the Component Process Model of Emotion

    PubMed Central

    Gentsch, Kornelia; Grandjean, Didier; Scherer, Klaus R.

    2015-01-01

    Scherer’s Component Process Model provides a theoretical framework for research on the production mechanism of emotion and facial emotional expression. The model predicts that appraisal results drive facial expressions, which unfold sequentially and cumulatively over time. In two experiments, we examined facial muscle activity changes (via facial electromyography recordings over the corrugator, cheek, and frontalis regions) in response to events in a gambling task. These events were experimentally manipulated feedback stimuli which presented simultaneous information directly affecting goal conduciveness (gambling outcome: win, loss, or break-even) and power appraisals (Experiment 1 and 2), as well as control appraisal (Experiment 2). We repeatedly found main effects of goal conduciveness (starting ~600 ms), and power appraisals (starting ~800 ms after feedback onset). Control appraisal main effects were inconclusive. Interaction effects of goal conduciveness and power appraisals were obtained in both experiments (Experiment 1: over the corrugator and cheek regions; Experiment 2: over the frontalis region) suggesting amplified goal conduciveness effects when power was high in contrast to invariant goal conduciveness effects when power was low. Also an interaction of goal conduciveness and control appraisals was found over the cheek region, showing differential goal conduciveness effects when control was high and invariant effects when control was low. These interaction effects suggest that the appraisal of having sufficient control or power affects facial responses towards gambling outcomes. The result pattern suggests that corrugator and frontalis regions are primarily related to cognitive operations that process motivational pertinence, whereas the cheek region would be more influenced by coping implications. Our results provide first evidence demonstrating that cognitive-evaluative mechanisms related to goal conduciveness, control, and power appraisals affect facial expressions dynamically over time, immediately after an event is perceived. In addition, our results provide further indications for the chronography of appraisal-driven facial movements and the underlying cognitive processes. PMID:26295338

  11. An application of a Hill-based response surface model for a drug combination experiment on lung cancer.

    PubMed

    Ning, Shaoyang; Xu, Hongquan; Al-Shyoukh, Ibrahim; Feng, Jiaying; Sun, Ren

    2014-10-30

    Combination chemotherapy with multiple drugs has been widely applied to cancer treatment owing to enhanced efficacy and reduced drug resistance. For drug combination experiment analysis, response surface modeling has been commonly adopted. In this paper, we introduce a Hill-based global response surface model and provide an application of the model to a 512-run drug combination experiment with three chemicals, namely AG490, U0126, and indirubin-3  ' -monoxime (I-3-M), on lung cancer cells. The results demonstrate generally improved goodness of fit of our model from the traditional polynomial model, as well as the original Hill model on the basis of fixed-ratio drug combinations. We identify different dose-effect patterns between normal and cancer cells on the basis of our model, which indicates the potential effectiveness of the drug combination in cancer treatment. Meanwhile, drug interactions are analyzed both qualitatively and quantitatively. The distinct interaction patterns between U0126 and I-3-M on two types of cells uncovered by the model could be a further indicator of the efficacy of the drug combination. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Assimilative modeling of low latitude ionosphere

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing; Wang, Chunining; Hajj, George A.; Rosen, I. Gary; Wilson, Brian D.; Mannucci, Anthony J.

    2004-01-01

    In this paper we present an observation system simulation experiment for modeling low-latitude ionosphere using a 3-dimensional (3-D) global assimilative ionospheric model (GAIM). The experiment is conducted to test the effectiveness of GAIM with a 4-D variational approach (4DVAR) in estimation of the ExB drift and thermospheric wind in the magnetic meridional planes simultaneously for all longitude or local time sectors. The operational Global Positioning System (GPS) satellites and the ground-based global GPS receiver network of the International GPS Service are used in the experiment as the data assimilation source. 'The optimization of the ionospheric state (electron density) modeling is performed through a nonlinear least-squares minimization process that adjusts the dynamical forces to reduce the difference between the modeled and observed slant total electron content in the entire modeled region. The present experiment for multiple force estimations reinforces our previous assessment made through single driver estimations conducted for the ExB drift only.

  13. The Effect of Transition Type in Multi-View 360° Media.

    PubMed

    MacQuarrie, Andrew; Steed, Anthony

    2018-04-01

    360° images and video have become extremely popular formats for immersive displays, due in large part to the technical ease of content production. While many experiences use a single camera viewpoint, an increasing number of experiences use multiple camera locations. In such multi-view 360° media (MV360M) systems, a visual effect is required when the user transitions from one camera location to another. This effect can take several forms, such as a cut or an image-based warp, and the choice of effect may impact many aspects of the experience, including issues related to enjoyment and scene understanding. To investigate the effect of transition types on immersive MV360M experiences, a repeated-measures experiment was conducted with 31 participants. Wearing a head-mounted display, participants explored four static scenes, for which multiple 360° images and a reconstructed 3D model were available. Three transition types were examined: teleport, a linear move through a 3D model of the scene, and an image-based transition using a Möbius transformation. The metrics investigated included spatial awareness, users' movement profiles, transition preference and the subjective feeling of moving through the space. Results indicate that there was no significant difference between transition types in terms of spatial awareness, while significant differences were found for users' movement profiles, with participants taking 1.6 seconds longer to select their next location following a teleport transition. The model and Möbius transitions were significantly better in terms of creating the feeling of moving through the space. Preference was also significantly different, with model and teleport transitions being preferred over Möbius transitions. Our results indicate that trade-offs between transitions will require content creators to think carefully about what aspects they consider to be most important when producing MV360M experiences.

  14. Idealized Experiments for Optimizing Model Parameters Using a 4D-Variational Method in an Intermediate Coupled Model of ENSO

    NASA Astrophysics Data System (ADS)

    Gao, Chuan; Zhang, Rong-Hua; Wu, Xinrong; Sun, Jichang

    2018-04-01

    Large biases exist in real-time ENSO prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4D variational (4D-Var) data assimilation system was developed for an intermediate coupled model (ICM) and used to improve ENSO modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for ENSO is related to the anomalous temperature of subsurface water entrained into the mixed layer ( T e), which is empirically and explicitly related to sea level (SL) variation. The strength of the thermocline effect on SST (referred to simply as "the thermocline effect") is represented by an introduced parameter, α Te. A numerical procedure is developed to optimize this model parameter through the 4D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having their initial condition optimized only, and having their initial condition plus this additional model parameter optimized, are compared. It is shown that ENSO evolution can be more effectively recovered by including the additional optimization of this parameter in ENSO modeling. The demonstrated feasibility of optimizing model parameters and initial conditions together through the 4D-Var method provides a modeling platform for ENSO studies. Further applications of the 4D-Var data assimilation system implemented in the ICM are also discussed.

  15. Teachers' Situation-Specific Mastery Experiences: Teacher, Student Group and Lesson Effects

    ERIC Educational Resources Information Center

    Malmberg, Lars-Erik; Hagger, Hazel; Webster, Sophie

    2014-01-01

    Following a model on the cyclical nature of teacher ("trait") self-efficacy and context-, task- and situation-specific ("state") "mastery experiences" (TSSME), we investigated the variability and effects of lesson characteristics (e.g. lesson sequence), student group characteristics (e.g. proportion of students…

  16. Learning Experiences in Medical Education.

    ERIC Educational Resources Information Center

    Leggat, Peter A.

    2000-01-01

    Discusses the learning experience from both traditional and computer-assisted instructional methods. Describes the environments in which these methods are effective. Focuses on learning experiences in medical education and describes educational strategies, particularly the 'SPICES' model. Discusses the importance of mentoring in the psychosocial…

  17. Effectiveness of discovery learning model on mathematical problem solving

    NASA Astrophysics Data System (ADS)

    Herdiana, Yunita; Wahyudin, Sispiyati, Ririn

    2017-08-01

    This research is aimed to describe the effectiveness of discovery learning model on mathematical problem solving. This research investigate the students' problem solving competency before and after learned by using discovery learning model. The population used in this research was student in grade VII in one of junior high school in West Bandung Regency. From nine classes, class VII B were randomly selected as the sample of experiment class, and class VII C as control class, which consist of 35 students every class. The method in this research was quasi experiment. The instrument in this research is pre-test, worksheet and post-test about problem solving of mathematics. Based on the research, it can be conclude that the qualification of problem solving competency of students who gets discovery learning model on level 80%, including in medium category and it show that discovery learning model effective to improve mathematical problem solving.

  18. A Stress and Coping Approach to Intervention with Abused Women.

    ERIC Educational Resources Information Center

    Carlson, Bonnie E.

    1997-01-01

    Presents an ecological model of intervention for physical abuse based on the Lazarus and Folkman conceptualization of stress and coping. Claims that the model identifies the stages that abused women may experience in their appraisal of the abuse experience. Focuses on barriers to ending abuse, stress and coping, and effective interventions. (RJM)

  19. Modeling and simulations of radiative blast wave driven Rayleigh-Taylor instability experiments

    NASA Astrophysics Data System (ADS)

    Shimony, Assaf; Huntington, Channing M.; Trantham, Matthew; Malamud, Guy; Elbaz, Yonatan; Kuranz, Carolyn C.; Drake, R. Paul; Shvarts, Dov

    2017-10-01

    Recent experiments at the National Ignition Facility measured the growth of Rayleigh-Taylor RT instabilities driven by radiative blast waves, relevant to astrophysics and other HEDP systems. We constructed a new Buoyancy-Drag (BD) model, which accounts for the ablation effect on both bubble and spike. This ablation effect is accounted for by using the potential flow model ]Oron et al PoP 1998], adding another term to the classical BD formalism: βDuA / u , where β the Takabe constant, D the drag term, uA the ablation velocity and uthe instability growth velocity. The model results are compared with the results of experiments and 2D simulations using the CRASH code, with nominal radiation or reduced foam opacity (by a factor of 1000). The ablation constant of the model, βb / s, for the bubble and for the spike fronts, are calibrated using the results of the radiative shock experiments. This work is funded by the Lawrence Livermore National Laboratory under subcontract B614207, and was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

  20. Magnitude and behavior of cross-talk effects in multichannel electrophysiology experiments.

    PubMed

    Nelson, Matthew J; Valtcheva, Silvana; Venance, Laurent

    2017-07-01

    Modern neurophysiological experiments frequently involve multiple channels separated by very small distances. A unique methodological concern for multiple-electrode experiments is that of capacitive coupling (cross-talk) between channels. Yet the nature of the cross-talk recording circuit is not well known in the field, and the extent to which it practically affects neurophysiology experiments has never been fully investigated. Here we describe a simple electrical circuit model of simultaneous recording and stimulation with two or more channels and experimentally verify the model using ex vivo brain slice and in vivo whole-brain preparations. In agreement with the model, we find that cross-talk amplitudes increase nearly linearly with the impedance of a recording electrode and are larger for higher frequencies. We demonstrate cross-talk contamination of action potential waveforms from intracellular to extracellular channels, which is observable in part because of the different orders of magnitude between the channels. This contamination is electrode impedance-dependent and matches predictions from the model. We use recently published parameters to simulate cross-talk in high-density multichannel extracellular recordings. Cross-talk effectively spatially smooths current source density (CSD) estimates in these recordings and induces artefactual phase shifts where underlying voltage gradients occur; however, these effects are modest. We show that the effects of cross-talk are unlikely to affect most conclusions inferred from neurophysiology experiments when both originating and receiving electrode record signals of similar magnitudes. We discuss other types of experiments and analyses that may be susceptible to cross-talk, techniques for detecting and experimentally reducing cross-talk, and implications for high-density probe design. NEW & NOTEWORTHY We develop and experimentally verify an electrical circuit model describing cross-talk that necessarily occurs between two channels. Recorded cross-talk increased with electrode impedance and signal frequency. We recorded cross-talk contamination of spike waveforms from intracellular to extracellular channels. We simulated high-density multichannel extracellular recordings and demonstrate spatial smoothing and phase shifts that cross-talk enacts on CSD measurements. However, when channels record similar-magnitude signals, effects are modest and unlikely to affect most conclusions. Copyright © 2017 the American Physiological Society.

  1. Analysis of the effectiveness of steam retorting of oil shale

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jacobs, H.R.; Pensel, R.W.; Udell, K.S.

    A numerical model is developed to describe the retorting of oil shale using superheated steam. The model describes not only the temperature history of the shale but predicts the evolution of shale oil from kerogen decomposition and the breakdown of the carbonates existing in the shale matrix. The heat transfer coefficients between the water and the shale are determined from experiments utilizing the model to reduce the data. Similarly the model is used with thermogravimetric analysis experiments to develop an improved kinetics expression for kerogen decomposition in a steam environment. Numerical results are presented which indicate the effect of oilmore » shale particle size and steam temperature on oil production.« less

  2. Vibrational kinetics in CO electric discharge lasers - Modeling and experiments

    NASA Technical Reports Server (NTRS)

    Stanton, A. C.; Hanson, R. K.; Mitchner, M.

    1980-01-01

    A model of CO laser vibrational kinetics is developed, and predicted vibrational distributions are compared with measurements. The experimental distributions were obtained at various flow locations in a transverse CW discharge in supersonic (M = 3) flow. Good qualitative agreement is obtained in the comparisons, including the prediction of a total inversion at low discharge current densities. The major area of discrepancy is an observed loss in vibrational energy downstream of the discharge which is not predicted by the model. This discrepancy may be due to three-dimensional effects in the experiment which are not included in the model. Possible kinetic effects which may contribute to vibrational energy loss are also examined.

  3. Assessing the effect of adding interactive modeling to the geoscience curriculum

    NASA Astrophysics Data System (ADS)

    Castillo, A.; Marshall, J.; Cardenas, M.

    2013-12-01

    Technology and computer models enhance the learning experience when appropriately utilized. Moreover, learning is significantly improved when effective visualization is combined with models of processes allowing for inquiry-based problem solving. Still, hands-on experiences in real scenarios result in better contextualization of related problems compared to virtual laboratories. Therefore, the role of scientific visualization, technology, and computer modeling is to enhance, not displace, the learning experience by supplementing real-world problem solving and experiences, although in some circumstances, they can adequately serve to take the place of reality. The key to improving scientific education is to embrace an inquiry-based approach that favorably uses technology. This study will attempt to evaluate the effect of adding interactive modeling to the geological sciences curriculum. An assessment tool, designed to assess student understanding of physical hydrology, was used to evaluate a curriculum intervention based on student learning with a data- and modeling-driven approach using COMSOL Multiphysics software. This intervention was implemented in an upper division and graduate physical hydrology course in fall 2012. Students enrolled in the course in fall 2011 served as the control group. Interactive modeling was added to the curriculum in fall 2012 to replace the analogous mathematical modeling done by hand in fall 2011. Pre- and post-test results were used to assess and report its effectiveness. Student interviews were also used to probe student reactions to both the experimental and control curricula. The pre- and post-tests asked students to describe the significant processes in the hydrological cycle and describe the laws governing these processes. Their ability to apply their knowledge in a real-world problem was also assessed. Since the pre- and post-test data failed to meet the assumption of normality, a non-parametric Kruskal-Wallis test was run to determine if there were differences in pre- and post-test scores among the 2011 and 2012 groups. Results reveal significant differences in pretest and posttest scores among the 2011 and 2012 groups. Interview data revealed that students experience both affordances and barriers to using geoscience learning tools. Important affordances included COMSOL's modeling capabilities, the visualizations it offers, as well as the opportunity to use the software in the course. Barriers included lack of COMSOL experience, difficulty with COMSOL instructions, and lack of instruction with the software. Results from this study revealed that a well-designed pre- and post-assessment can be used to infer whether a given instructional intervention has caused a change in understanding in a given group of students, but the results are not necessarily generalizable. However, the student interviews, which were used to probe student reactions to both the experimental and control curricula, revealed that students experience both affordances and barriers to geoscience learning tools. This result has limitations including the number of participants, all from one institution, but the assessment tool was useful to assess the effect of adding interactive modeling to the geoscience curriculum. Supported by NSF CAREER grant (EAR-0955750).

  4. Influence of defects on the thermal conductivity of compressed LiF

    DOE PAGES

    Jones, R. E.; Ward, D. K.

    2018-02-08

    We report defect formation in LiF, which is used as an observation window in ramp and shock experiments, has significant effects on its transmission properties. Given the extreme conditions of the experiments it is hard to measure the change in transmission directly. Using molecular dynamics, we estimate the change in conductivity as a function of the concentration of likely point and extended defects using a Green-Kubo technique with careful treatment of size effects. With this data, we form a model of the mean behavior and its estimated error; then, we use this model to predict the conductivity of a largemore » sample of defective LiF resulting from a direct simulation of ramp compression as a demonstration of the accuracy of its predictions. Given estimates of defect densities in a LiF window used in an experiment, the model can be used to correct the observations of thermal energy through the window. Also, the methodology we develop is extensible to modeling, with quantified uncertainty, the effects of a variety of defects on the thermal conductivity of solid materials.« less

  5. A model for evidence accumulation in the lexical decision task.

    PubMed

    Wagenmakers, Eric-Jan; Steyvers, Mark; Raaijmakers, Jeroen G W; Shiffrin, Richard M; van Rijn, Hedderik; Zeelenberg, René

    2004-05-01

    We present a new model for lexical decision, REM-LD, that is based on REM theory (e.g., ). REM-LD uses a principled (i.e., Bayes' rule) decision process that simultaneously considers the diagnosticity of the evidence for the 'WORD' response and the 'NONWORD' response. The model calculates the odds ratio that the presented stimulus is a word or a nonword by averaging likelihood ratios for lexical entries from a small neighborhood of similar words. We report two experiments that used a signal-to-respond paradigm to obtain information about the time course of lexical processing. Experiment 1 verified the prediction of the model that the frequency of the word stimuli affects performance for nonword stimuli. Experiment 2 was done to study the effects of nonword lexicality, word frequency, and repetition priming and to demonstrate how REM-LD can account for the observed results. We discuss how REM-LD could be extended to account for effects of phonology such as the pseudohomophone effect, and how REM-LD can predict response times in the traditional 'respond-when-ready' paradigm.

  6. Influence of defects on the thermal conductivity of compressed LiF

    NASA Astrophysics Data System (ADS)

    Jones, R. E.; Ward, D. K.

    2018-02-01

    Defect formation in LiF, which is used as an observation window in ramp and shock experiments, has significant effects on its transmission properties. Given the extreme conditions of the experiments it is hard to measure the change in transmission directly. Using molecular dynamics, we estimate the change in conductivity as a function of the concentration of likely point and extended defects using a Green-Kubo technique with careful treatment of size effects. With this data, we form a model of the mean behavior and its estimated error; then, we use this model to predict the conductivity of a large sample of defective LiF resulting from a direct simulation of ramp compression as a demonstration of the accuracy of its predictions. Given estimates of defect densities in a LiF window used in an experiment, the model can be used to correct the observations of thermal energy through the window. In addition, the methodology we develop is extensible to modeling, with quantified uncertainty, the effects of a variety of defects on the thermal conductivity of solid materials.

  7. Influence of defects on the thermal conductivity of compressed LiF

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, R. E.; Ward, D. K.

    We report defect formation in LiF, which is used as an observation window in ramp and shock experiments, has significant effects on its transmission properties. Given the extreme conditions of the experiments it is hard to measure the change in transmission directly. Using molecular dynamics, we estimate the change in conductivity as a function of the concentration of likely point and extended defects using a Green-Kubo technique with careful treatment of size effects. With this data, we form a model of the mean behavior and its estimated error; then, we use this model to predict the conductivity of a largemore » sample of defective LiF resulting from a direct simulation of ramp compression as a demonstration of the accuracy of its predictions. Given estimates of defect densities in a LiF window used in an experiment, the model can be used to correct the observations of thermal energy through the window. Also, the methodology we develop is extensible to modeling, with quantified uncertainty, the effects of a variety of defects on the thermal conductivity of solid materials.« less

  8. Analysis of radiative and phase-change phenomena with application to space-based thermal energy storage

    NASA Technical Reports Server (NTRS)

    Lund, Kurt O.

    1991-01-01

    The simplified geometry for the analysis is an infinite, axis symmetric annulus with a specified solar flux at the outer radius. The inner radius is either adiabatic (modeling Flight Experiment conditions), or convective (modeling Solar Dynamic conditions). Liquid LiF either contacts the outer wall (modeling ground based testing), or faces a void gap at the outer wall (modeling possible space based conditions). The analysis is presented in three parts: Part 3 considers and adiabatic inner wall and linearized radiation equations; part 2 adds effects of convection at the inner wall; and part 1 includes the effect of the void gap, as well as previous effects, and develops the radiation model further. The main results are the differences in melting behavior which can occur between ground based 1 g experiments and the microgravity flight experiments. Under 1 gravity, melted PCM will always contact the outer wall having the heat flux source, thus providing conductance from this source to the phase change front. In space based tests where a void gap may likely form during solidification, the situation is reversed; radiation is now the only mode of heat transfer and the majority of melting takes place from the inner wall.

  9. The impact of geoengineering on vegetation in experiment G1 of the GeoMIP

    NASA Astrophysics Data System (ADS)

    Glienke, Susanne; Irvine, Peter J.; Lawrence, Mark G.

    2015-10-01

    Solar Radiation Management (SRM) has been proposed as a mean to partly counteract global warming. The Geoengineering Model Intercomparison Project (GeoMIP) has simulated the climate consequences of a number of SRM techniques. Thus far, the effects on vegetation have not yet been thoroughly analyzed. Here the vegetation response to the idealized GeoMIP G1 experiment from eight fully coupled Earth system models (ESMs) is analyzed, in which a reduction of the solar constant counterbalances the radiative effects of quadrupled atmospheric CO2 concentrations (abrupt4 × CO2). For most models and regions, changes in net primary productivity (NPP) are dominated by the increase in CO2, via the CO2 fertilization effect. As SRM will reduce temperatures relative to abrupt4 × CO2, in high latitudes this will offset increases in NPP. In low latitudes, this cooling relative to the abrupt4 × CO2 simulation decreases plant respiration while having little effect on gross primary productivity, thus increasing NPP. In Central America and the Mediterranean, generally dry regions which are expected to experience increased water stress with global warming, NPP is highest in the G1 experiment for all models due to the easing of water limitations from increased water use efficiency at high-CO2 concentrations and the reduced evaporative demand in a geoengineered climate. The largest differences in the vegetation response are between models with and without a nitrogen cycle, with a much smaller CO2 fertilization effect for the former. These results suggest that until key vegetation processes are integrated into ESM predictions, the vegetation response to SRM will remain highly uncertain.

  10. Innovative Liner Concepts: Experiments and Impedance Modeling of Liners Including the Effect of Bias Flow

    NASA Technical Reports Server (NTRS)

    Kelly, Jeff; Betts, Juan Fernando; Fuller, Chris

    2000-01-01

    The study of normal impedance of perforated plate acoustic liners including the effect of bias flow was studied. Two impedance models were developed by modeling the internal flows of perforate orifices as infinite tubes with the inclusion of end corrections to handle finite length effects. These models assumed incompressible and compressible flows, respectively, between the far field and the perforate orifice. The incompressible model was used to predict impedance results for perforated plates with percent open areas ranging from 5% to 15%. The predicted resistance results showed better agreement with experiments for the higher percent open area samples. The agreement also tended to deteriorate as bias flow was increased. For perforated plates with percent open areas ranging from 1% to 5%, the compressible model was used to predict impedance results. The model predictions were closer to the experimental resistance results for the 2% to 3% open area samples. The predictions tended to deteriorate as bias flow was increased. The reactance results were well predicted by the models for the higher percent open area, but deteriorated as the percent open area was lowered (5%) and bias flow was increased. A fit was done on the incompressible model to the experimental database. The fit was performed using an optimization routine that found the optimal set of multiplication coefficients to the non-dimensional groups that minimized the least squares slope error between predictions and experiments. The result of the fit indicated that terms not associated with bias flow required a greater degree of correction than the terms associated with the bias flow. This model improved agreement with experiments by nearly 15% for the low percent open area (5%) samples when compared to the unfitted model. The fitted model and the unfitted model performed equally well for the higher percent open area (10% and 15%).

  11. Repeatability of Mice Consumption Discrimination of Wheat (Triticum aestivum L.) Varieties across Field Experiments and Mouse Cohorts.

    PubMed

    Kiszonas, Alecia M; Fuerst, E Patrick; Morris, Craig F

    2015-07-01

    Whole grain wheat (Triticum aestivum L.) foods can provide critical nutrients for health and nutrition in the human diet. Potential flavor differences among varieties can be examined using consumption discrimination of the house mouse (Mus musculus L.) as a model system. This study examines consistency and repeatability of the mouse model and potentially, wheat grain flavor. A single elimination tournament design was used to measure relative consumption preference for hard red spring and hard white spring varieties across all 3 experiments in combination with 2 mouse cohorts. Fifteen replicate mice were used in 24-h trials to examine differences in preference among paired wheat varieties until an overall "winner" was established as the most highly preferred variety of wheat. In all 3 experiment-cohort combinations, the same varieties were preferred as the "winner" of both the hard red spring and hard white spring wheat varieties, Hollis and BR 7030, respectively. Despite the consistent preference for these varieties across experiments, the degree (magnitude) to which the mice preferred these varieties varied across experiments. For the hard white spring wheat varieties, the small number of varieties and confounding effects of experiment and cohort limited our ability to accurately gauge repeatability. Conversely, for the hard red spring wheat varieties, consumption preferences were consistent across experiments and mice cohorts. The single-elimination tournament model was effective in providing repeatable results in an effort to more fully understand the mouse model system and possible flavor differences among wheat varieties. The mouse model system used here is effective in identifying wheat varieties that may be more or less desirable to humans in whole wheat foods. The system identifies consistent differences across different mouse cohorts and crop years. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  12. Pore-scale and Continuum Simulations of Solute Transport Micromodel Benchmark Experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oostrom, Martinus; Mehmani, Yashar; Romero Gomez, Pedro DJ

    Four sets of micromodel nonreactive solute transport experiments were conducted with flow velocity, grain diameter, pore-aspect ratio, and flow focusing heterogeneity as the variables. The data sets were offered to pore-scale modeling groups to test their simulators. Each set consisted of two learning experiments, for which all results was made available, and a challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing, and considerably enhanced mixing due to flow focusing.more » Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice-Boltzmann (LB) approach, and one employed a computational fluid dynamics (CFD) technique. The learning experiments were used by the PN models to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used these experiments to appropriately discretize the grid representations. The continuum model use published non-linear relations between transverse dispersion coefficients and Peclet numbers to compute the required dispersivity input values. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values and, resulting in less dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models needed up to several days on supercomputers to resolve the more complex problems.« less

  13. Applying 3-PG, a simple process-based model designed to produce practical results, to data from loblolly pine experiments

    Treesearch

    Joe J. Landsberg; Kurt H. Johnsen; Timothy J. Albaugh; H. Lee Allen; Steven E. McKeand

    2001-01-01

    3-PG is a simple process-based model that requires few parameter values and only readily available input data. We tested the structure of the model by calibrating it against loblolly pine data from the control treatment of the SETRES experiment in Scotland County, NC, then altered the fertility rating to simulate the effects of fertilization. There was excellent...

  14. On the Dissociation of Word/Nonword Repetition Effects in Lexical Decision: An Evidence Accumulation Account.

    PubMed

    Perea, Manuel; Marcet, Ana; Vergara-Martínez, Marta; Gomez, Pablo

    2016-01-01

    A number of models of visual-word recognition assume that the repetition of an item in a lexical decision experiment increases that item's familiarity/wordness. This would produce not only a facilitative repetition effect for words, but also an inhibitory effect for nonwords (i.e., more familiarity/wordness makes the negative decision slower). We conducted a two-block lexical decision experiment to examine word/nonword repetition effects in the framework of a leading "familiarity/wordness" model of the lexical decision task, namely, the diffusion model (Ratcliff et al., 2004). Results showed that while repeated words were responded to faster than the unrepeated words, repeated nonwords were responded to more slowly than the nonrepeated nonwords. Fits from the diffusion model revealed that the repetition effect for words/nonwords was mainly due to differences in the familiarity/wordness (drift rate) parameter. This word/nonword dissociation favors those accounts that posit that the previous presentation of an item increases its degree of familiarity/wordness.

  15. On the Dissociation of Word/Nonword Repetition Effects in Lexical Decision: An Evidence Accumulation Account

    PubMed Central

    Perea, Manuel; Marcet, Ana; Vergara-Martínez, Marta; Gomez, Pablo

    2016-01-01

    A number of models of visual-word recognition assume that the repetition of an item in a lexical decision experiment increases that item's familiarity/wordness. This would produce not only a facilitative repetition effect for words, but also an inhibitory effect for nonwords (i.e., more familiarity/wordness makes the negative decision slower). We conducted a two-block lexical decision experiment to examine word/nonword repetition effects in the framework of a leading “familiarity/wordness” model of the lexical decision task, namely, the diffusion model (Ratcliff et al., 2004). Results showed that while repeated words were responded to faster than the unrepeated words, repeated nonwords were responded to more slowly than the nonrepeated nonwords. Fits from the diffusion model revealed that the repetition effect for words/nonwords was mainly due to differences in the familiarity/wordness (drift rate) parameter. This word/nonword dissociation favors those accounts that posit that the previous presentation of an item increases its degree of familiarity/wordness. PMID:26925021

  16. Pharmacokinetic-Pharmacodynamic Modeling of the Anti-Tumor Effect of Sunitinib Combined with Dopamine in the Human Non-Small Cell Lung Cancer Xenograft.

    PubMed

    Hao, Fangran; Wang, Siyuan; Zhu, Xiao; Xue, Junsheng; Li, Jingyun; Wang, Lijie; Li, Jian; Lu, Wei; Zhou, Tianyan

    2017-02-01

    To investigate the anti-tumor effect of sunitinib in combination with dopamine in the treatment of nu/nu nude mice bearing non-small cell lung cancer (NSCLC) A549 cells and to develop the combination PK/PD model. Further, simulations were conducted to optimize the administration regimens. A PK/PD model was developed based on our preclinical experiment to explore the relationship between plasma concentration and drug effect quantitatively. Further, the model was evaluated and validated. By fixing the parameters obtained from the PK/PD model, simulations were built to predict the tumor suppression under various regimens. The synergistic effect was observed between sunitinib and dopamine in the study, which was confirmed by the effect constant (GAMA, estimated as 2.49). The enhanced potency of dopamine on sunitinib was exerted by on/off effect in the PK/PD model. The optimal dose regimen was selected as sunitinib (120 mg/kg, q3d) in combination with dopamine (2 mg/kg, q3d) based on the simulation study. The synergistic effect of sunitinib and dopamine was demonstrated by the preclinical experiment and confirmed by the developed PK/PD model. In addition, the regimens were optimized by means of modeling as well as simulation, which may be conducive to clinical study.

  17. Dark matter effective field theory scattering in direct detection experiments

    DOE PAGES

    Schneck, K.

    2015-05-01

    We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implicationsmore » of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.« less

  18. Dark matter effective field theory scattering in direct detection experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.

    2015-05-18

    We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. Here. we demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. In conclusion, we discussmore » the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.« less

  19. Dark matter effective field theory scattering in direct detection experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.

    2015-05-18

    We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implicationsmore » of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.« less

  20. The effects of associative and semantic priming in the lexical decision task.

    PubMed

    Perea, Manuel; Rosa, Eva

    2002-08-01

    Four lexical decision experiments were conducted to examine under which conditions automatic semantic priming effects can be obtained. Experiments 1 and 2 analyzed associative/semantic effects at several very short stimulus-onset asynchronies (SOAs), whereas Experiments 3 and 4 used a single-presentation paradigm at two response-stimulus intervals (RSIs). Experiment 1 tested associatively related pairs from three semantic categories (synonyms, antonyms, and category coordinates). The results showed reliable associative priming effects at all SOAs. In addition, the correlation between associative strength and magnitude of priming was significant only at the shortest SOA (66 ms). When prime-target pairs were semantically but not associatively related (Experiment 2), reliable priming effects were obtained at SOAs of 83 ms and longer. Using the single-presentation paradigm with a short RSI (200 ms, Experiment 3), the priming effect was equal in size for associative + semantic and for semantic-only pairs (a 21-ms effect). When the RSI was set much longer (1,750 ms, Experiment 4), only the associative + semantic pairs showed a reliable priming effect (23 ms). The results are interpreted in the context of models of semantic memory.

  1. Blocking Effects in the Learning of Chinese Classifiers

    ERIC Educational Resources Information Center

    Paul, Jing Z.; Grüter, Theres

    2016-01-01

    This study investigated order-of-learning effects on the acquisition of classifier-noun associations in Chinese in two experiments modeled after Arnon and Ramscar's (2012) study of artificial language learning. In Experiment 1, learners with no prior exposure to Chinese showed better learning of classifier-noun associations when exposed to larger…

  2. Comparing the Effect of Two Internship Structures on Supervision Experience and Learning

    ERIC Educational Resources Information Center

    Winslow, Robin D.; Eliason, Meghan; Thiede, Keith W.

    2016-01-01

    The purpose of this study was to examine two different models of internship and competitively evaluate their effectiveness in influencing interns' experience, beliefs, and knowledge of supervision. The research questions for this study were developed from the literature on supervision of instruction and internships in educational leadership…

  3. Robust optical flow using adaptive Lorentzian filter for image reconstruction under noisy condition

    NASA Astrophysics Data System (ADS)

    Kesrarat, Darun; Patanavijit, Vorapoj

    2017-02-01

    In optical flow for motion allocation, the efficient result in Motion Vector (MV) is an important issue. Several noisy conditions may cause the unreliable result in optical flow algorithms. We discover that many classical optical flows algorithms perform better result under noisy condition when combined with modern optimized model. This paper introduces effective robust models of optical flow by using Robust high reliability spatial based optical flow algorithms using the adaptive Lorentzian norm influence function in computation on simple spatial temporal optical flows algorithm. Experiment on our proposed models confirm better noise tolerance in optical flow's MV under noisy condition when they are applied over simple spatial temporal optical flow algorithms as a filtering model in simple frame-to-frame correlation technique. We illustrate the performance of our models by performing an experiment on several typical sequences with differences in movement speed of foreground and background where the experiment sequences are contaminated by the additive white Gaussian noise (AWGN) at different noise decibels (dB). This paper shows very high effectiveness of noise tolerance models that they are indicated by peak signal to noise ratio (PSNR).

  4. On the effect of response transformations in sequential parameter optimization.

    PubMed

    Wagner, Tobias; Wessing, Simon

    2012-01-01

    Parameter tuning of evolutionary algorithms (EAs) is attracting more and more interest. In particular, the sequential parameter optimization (SPO) framework for the model-assisted tuning of stochastic optimizers has resulted in established parameter tuning algorithms. In this paper, we enhance the SPO framework by introducing transformation steps before the response aggregation and before the actual modeling. Based on design-of-experiments techniques, we empirically analyze the effect of integrating different transformations. We show that in particular, a rank transformation of the responses provides significant improvements. A deeper analysis of the resulting models and additional experiments with adaptive procedures indicates that the rank and the Box-Cox transformation are able to improve the properties of the resultant distributions with respect to symmetry and normality of the residuals. Moreover, model-based effect plots document a higher discriminatory power obtained by the rank transformation.

  5. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wardaya, P. D., E-mail: pongga.wardaya@utp.edu.my; Noh, K. A. B. M., E-mail: pongga.wardaya@utp.edu.my; Yusoff, W. I. B. W., E-mail: pongga.wardaya@utp.edu.my

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, anmore » advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave velocity of rock.« less

  6. Student Engagement as a General Factor of Classroom Experience: Associations with Student Practices and Educational Outcomes in a University Gateway Course

    PubMed Central

    Shernof, David J.; Ruzek, Erik A.; Sannella, Alexander J.; Schorr, Roberta Y.; Sanchez-Wall, Lina; Bressler, Denise M.

    2017-01-01

    The purpose of this study was to evaluate a model for considering general and specific elements of student experience in a gateway course in undergraduate Financial Accounting in a large university on the East Coast, USA. Specifically, the study evaluated a bifactor analytic strategy including a general factor of student classroom experience, conceptualized as student engagement as rooted in flow theory, as well as factors representing specific dimensions of experience. The study further evaluated the association between these general and specific factors and both student classroom practices and educational outcomes. The sample of students (N = 407) in two cohorts of the undergraduate financial accounting course participated in the Experience Sampling Method (ESM) measuring students' classroom practices, perceptions, engagement, and perceived learning throughout the one-semester course. Course grade information was also collected. Results showed that a two-level bifactor model fit the data better than two traditional (i.e., non-bifactor) models and also avoided significant multicollinearity of the traditional models. In addition to student engagement (general factor), specific dimensions of classroom experience in the bifactor model at the within-student level included intrinsic motivation, academic intensity, salience, and classroom self-esteem. At the between-student level, specific aspects included work orientation, learning orientation, classroom self-esteem, and disengagement. Multilevel Structural Equation Modeling (MSEM) demonstrated that sitting in the front of the classroom (compared to the sitting in the back), taking notes, active listening, and working on problems during class had a positive effect on within-student variation in student engagement and attention. Engagement, in turn, predicted perceived learning. With respect to between-student effects, the tendency to sit in front seats had a significant effect on student engagement, which in turn had a significant effect on perceived learning and course grades. A significant indirect relationship of seating and active learning strategies on learning and course grade as mediated by student engagement was found. Support for the general aspect of student classroom experience was interpreted with flow theory and suggested the need for additional research. Findings also suggested that active learning strategies are associated with positive learning outcomes even in educational environments where possibilities for action are relatively constrained. PMID:28663733

  7. Student Engagement as a General Factor of Classroom Experience: Associations with Student Practices and Educational Outcomes in a University Gateway Course.

    PubMed

    Shernof, David J; Ruzek, Erik A; Sannella, Alexander J; Schorr, Roberta Y; Sanchez-Wall, Lina; Bressler, Denise M

    2017-01-01

    The purpose of this study was to evaluate a model for considering general and specific elements of student experience in a gateway course in undergraduate Financial Accounting in a large university on the East Coast, USA. Specifically, the study evaluated a bifactor analytic strategy including a general factor of student classroom experience, conceptualized as student engagement as rooted in flow theory, as well as factors representing specific dimensions of experience. The study further evaluated the association between these general and specific factors and both student classroom practices and educational outcomes. The sample of students ( N = 407) in two cohorts of the undergraduate financial accounting course participated in the Experience Sampling Method (ESM) measuring students' classroom practices, perceptions, engagement, and perceived learning throughout the one-semester course. Course grade information was also collected. Results showed that a two-level bifactor model fit the data better than two traditional (i.e., non-bifactor) models and also avoided significant multicollinearity of the traditional models. In addition to student engagement (general factor), specific dimensions of classroom experience in the bifactor model at the within-student level included intrinsic motivation, academic intensity, salience, and classroom self-esteem. At the between-student level, specific aspects included work orientation, learning orientation, classroom self-esteem, and disengagement. Multilevel Structural Equation Modeling (MSEM) demonstrated that sitting in the front of the classroom (compared to the sitting in the back), taking notes, active listening, and working on problems during class had a positive effect on within-student variation in student engagement and attention. Engagement, in turn, predicted perceived learning. With respect to between-student effects, the tendency to sit in front seats had a significant effect on student engagement, which in turn had a significant effect on perceived learning and course grades. A significant indirect relationship of seating and active learning strategies on learning and course grade as mediated by student engagement was found. Support for the general aspect of student classroom experience was interpreted with flow theory and suggested the need for additional research. Findings also suggested that active learning strategies are associated with positive learning outcomes even in educational environments where possibilities for action are relatively constrained.

  8. Effects of stimulus order on discrimination processes in comparative and equality judgements: data and models.

    PubMed

    Dyjas, Oliver; Ulrich, Rolf

    2014-01-01

    In typical discrimination experiments, participants are presented with a constant standard and a variable comparison stimulus and their task is to judge which of these two stimuli is larger (comparative judgement). In these experiments, discrimination sensitivity depends on the temporal order of these stimuli (Type B effect) and is usually higher when the standard precedes rather than follows the comparison. Here, we outline how two models of stimulus discrimination can account for the Type B effect, namely the weighted difference model (or basic Sensation Weighting model) and the Internal Reference Model. For both models, the predicted psychometric functions for comparative judgements as well as for equality judgements, in which participants indicate whether they perceived the two stimuli to be equal or not equal, are derived and it is shown that the models also predict a Type B effect for equality judgements. In the empirical part, the models' predictions are evaluated. To this end, participants performed a duration discrimination task with comparative judgements and with equality judgements. In line with the models' predictions, a Type B effect was observed for both judgement types. In addition, a time-order error, as indicated by shifts of the psychometric functions, and differences in response times were observed only for the equality judgement. Since both models entail distinct additional predictions, it seems worthwhile for future research to unite the two models into one conceptual framework.

  9. Using the QUAIT Model to Effectively Teach Research Methods Curriculum to Master's-Level Students

    ERIC Educational Resources Information Center

    Hamilton, Nancy J.; Gitchel, Dent

    2017-01-01

    Purpose: To apply Slavin's model of effective instruction to teaching research methods to master's-level students. Methods: Barriers to the scientist-practitioner model (student research experience, confidence, and utility value pertaining to research methods as well as faculty research and pedagogical incompetencies) are discussed. Results: The…

  10. A Joint Modeling Approach for Reaction Time and Accuracy in Psycholinguistic Experiments

    ERIC Educational Resources Information Center

    Loeys, T.; Rosseel, Y.; Baten, K.

    2011-01-01

    In the psycholinguistic literature, reaction times and accuracy can be analyzed separately using mixed (logistic) effects models with crossed random effects for item and subject. Given the potential correlation between these two outcomes, a joint model for the reaction time and accuracy may provide further insight. In this paper, a Bayesian…

  11. ACCELERATED FAILURE TIME MODELS PROVIDE A USEFUL STATISTICAL FRAMEWORK FOR AGING RESEARCH

    PubMed Central

    Swindell, William R.

    2009-01-01

    Survivorship experiments play a central role in aging research and are performed to evaluate whether interventions alter the rate of aging and increase lifespan. The accelerated failure time (AFT) model is seldom used to analyze survivorship data, but offers a potentially useful statistical approach that is based upon the survival curve rather than the hazard function. In this study, AFT models were used to analyze data from 16 survivorship experiments that evaluated the effects of one or more genetic manipulations on mouse lifespan. Most genetic manipulations were found to have a multiplicative effect on survivorship that is independent of age and well-characterized by the AFT model “deceleration factor”. AFT model deceleration factors also provided a more intuitive measure of treatment effect than the hazard ratio, and were robust to departures from modeling assumptions. Age-dependent treatment effects, when present, were investigated using quantile regression modeling. These results provide an informative and quantitative summary of survivorship data associated with currently known long-lived mouse models. In addition, from the standpoint of aging research, these statistical approaches have appealing properties and provide valuable tools for the analysis of survivorship data. PMID:19007875

  12. Accelerated failure time models provide a useful statistical framework for aging research.

    PubMed

    Swindell, William R

    2009-03-01

    Survivorship experiments play a central role in aging research and are performed to evaluate whether interventions alter the rate of aging and increase lifespan. The accelerated failure time (AFT) model is seldom used to analyze survivorship data, but offers a potentially useful statistical approach that is based upon the survival curve rather than the hazard function. In this study, AFT models were used to analyze data from 16 survivorship experiments that evaluated the effects of one or more genetic manipulations on mouse lifespan. Most genetic manipulations were found to have a multiplicative effect on survivorship that is independent of age and well-characterized by the AFT model "deceleration factor". AFT model deceleration factors also provided a more intuitive measure of treatment effect than the hazard ratio, and were robust to departures from modeling assumptions. Age-dependent treatment effects, when present, were investigated using quantile regression modeling. These results provide an informative and quantitative summary of survivorship data associated with currently known long-lived mouse models. In addition, from the standpoint of aging research, these statistical approaches have appealing properties and provide valuable tools for the analysis of survivorship data.

  13. The Effects of Panax ginseng and Panax quinquefolius on Thermoregulation in Animal Models

    PubMed Central

    Hong, Bin Na; Do, Moon Ho; Her, You Ri

    2015-01-01

    We devised a study using animal models of hyperthermia and hypothermia and also attempted to accurately assess the effects of Panax ginseng (PG) and Panax quinquefolius (PQ) on body temperature using these models. In addition, we investigated the effects of PG and PQ in our animal models in high and low temperature environments. The results of our experiments show that mice with normothermia, hyperthermia, and hypothermia maintained their body temperatures after a certain period in accordance with the condition of each animal model. In our experiments of body temperature change in models of normal, low, or high room temperature, the hyperthermic model did not show any body temperature change in either the PG- or PQ-administered group. In the normal and low room temperature models, the group administered PG maintained body temperature, while the body temperature of the PQ-administered group was lower than or similar to that of the control group. In conclusion, the fact that PG increases body temperature could not be verified until now. We also showed that the effect of maintaining body temperature in the PG-administered group was superior in a hypothermia-prone low temperature environment. PMID:25709709

  14. Effect of gravity on colloid transport through water-saturated columns packed with glass beads: modeling and experiments.

    PubMed

    Chrysikopoulos, Constantinos V; Syngouna, Vasiliki I

    2014-06-17

    The role of gravitational force on colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q = 1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one-dimensional, colloid transport model. The effect of gravity is incorporated in the mathematical model by combining the interstitial velocity (advection) with the settling velocity (gravity effect). The results revealed that flow direction influences colloid transport in porous media. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for colloid deposition.

  15. Positive Adjustment Among American Repatriated Prisoners of the Vietnam War: Modeling the Long-Term Effects of Captivity.

    PubMed

    King, Daniel W; King, Lynda A; Park, Crystal L; Lee, Lewina O; Kaiser, Anica Pless; Spiro, Avron; Moore, Jeffrey L; Kaloupek, Danny G; Keane, Terence M

    2015-11-01

    A longitudinal lifespan model of factors contributing to later-life positive adjustment was tested on 567 American repatriated prisoners from the Vietnam War. This model encompassed demographics at time of capture and attributes assessed after return to the U.S. (reports of torture and mental distress) and approximately 3 decades later (later-life stressors, perceived social support, positive appraisal of military experiences, and positive adjustment). Age and education at time of capture and physical torture were associated with repatriation mental distress, which directly predicted poorer adjustment 30 years later. Physical torture also had a salutary effect, enhancing later-life positive appraisals of military experiences. Later-life events were directly and indirectly (through concerns about retirement) associated with positive adjustment. Results suggest that the personal resources of older age and more education and early-life adverse experiences can have cascading effects over the lifespan to impact well-being in both positive and negative ways.

  16. Positive Adjustment Among American Repatriated Prisoners of the Vietnam War: Modeling the Long-Term Effects of Captivity

    PubMed Central

    King, Daniel W.; King, Lynda A.; Park, Crystal L.; Lee, Lewina O.; Kaiser, Anica Pless; Spiro, Avron; Moore, Jeffrey L.; Kaloupek, Danny G.; Keane, Terence M.

    2015-01-01

    A longitudinal lifespan model of factors contributing to later-life positive adjustment was tested on 567 American repatriated prisoners from the Vietnam War. This model encompassed demographics at time of capture and attributes assessed after return to the U.S. (reports of torture and mental distress) and approximately 3 decades later (later-life stressors, perceived social support, positive appraisal of military experiences, and positive adjustment). Age and education at time of capture and physical torture were associated with repatriation mental distress, which directly predicted poorer adjustment 30 years later. Physical torture also had a salutary effect, enhancing later-life positive appraisals of military experiences. Later-life events were directly and indirectly (through concerns about retirement) associated with positive adjustment. Results suggest that the personal resources of older age and more education and early-life adverse experiences can have cascading effects over the lifespan to impact well-being in both positive and negative ways. PMID:26693100

  17. Shared identity is key to effective communication.

    PubMed

    Greenaway, Katharine H; Wright, Ruth G; Willingham, Joanne; Reynolds, Katherine J; Haslam, S Alexander

    2015-02-01

    The ability to communicate with others is one of the most important human social functions, yet communication is not always investigated from a social perspective. This research examined the role that shared social identity plays in communication effectiveness using a minimal group paradigm. In two experiments, participants constructed a model using instructions that were said to be created by an ingroup or an outgroup member. Participants made models of objectively better quality when working from communications ostensibly created by an ingroup member (Experiments 1 and 2). However, this effect was attenuated when participants were made aware of a shared superordinate identity that included both the ingroup and the outgroup (Experiment 2). These findings point to the importance of shared social identity for effective communication and provide novel insights into the social psychology of communication. © 2014 by the Society for Personality and Social Psychology, Inc.

  18. The effect of noise-induced variance on parameter recovery from reaction times.

    PubMed

    Vadillo, Miguel A; Garaizar, Pablo

    2016-03-31

    Technical noise can compromise the precision and accuracy of the reaction times collected in psychological experiments, especially in the case of Internet-based studies. Although this noise seems to have only a small impact on traditional statistical analyses, its effects on model fit to reaction-time distributions remains unexplored. Across four simulations we study the impact of technical noise on parameter recovery from data generated from an ex-Gaussian distribution and from a Ratcliff Diffusion Model. Our results suggest that the impact of noise-induced variance tends to be limited to specific parameters and conditions. Although we encourage researchers to adopt all measures to reduce the impact of noise on reaction-time experiments, we conclude that the typical amount of noise-induced variance found in these experiments does not pose substantial problems for statistical analyses based on model fitting.

  19. Using an experimental model for the study of therapeutic touch.

    PubMed

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  20. Class of cooperative stochastic models: Exact and approximate solutions, simulations, and experiments using ionic self-assembly of nanoparticles.

    PubMed

    Mazilu, I; Mazilu, D A; Melkerson, R E; Hall-Mejia, E; Beck, G J; Nshimyumukiza, S; da Fonseca, Carlos M

    2016-03-01

    We present exact and approximate results for a class of cooperative sequential adsorption models using matrix theory, mean-field theory, and computer simulations. We validate our models with two customized experiments using ionically self-assembled nanoparticles on glass slides. We also address the limitations of our models and their range of applicability. The exact results obtained using matrix theory can be applied to a variety of two-state systems with cooperative effects.

  1. Animal models and their importance to human physiological responses in microgravity

    NASA Technical Reports Server (NTRS)

    Tipton, C. M.

    1996-01-01

    Two prominent theories to explain the physiological effects of microgravity relate to the cascade of changes associated with the cephalic shifts of fluids and the absence of tissue deformation forces. One-g experiments for humans used bed rest and the head-down tilt (HDT) method, while animal experiments have been conducted using the tail-suspended, head-down, and hindlimbs non-weightbearing model. Because of the success of the HDT approach with rats to simulate the gravitational effects on the musculoskeletal system exhibited by humans, the same model has been used to study the effects of gravity on the cardiopulmonary systems of humans and other vertebrates. Results to date indicate the model is effective in producing comparable changes associated with blood volume, erythropoiesis, cardiac mass, baroreceptor responsiveness, carbohydrate metabolism, post-flight VO2max, and post-flight cardiac output during exercise. Inherent with these results is the potential of the model to be useful in investigating responsible mechanisms. The suspension model has promise in understanding the capillary blood PO2 changes in space as well as the arterial PO2 changes in subjects participating in a HDT experiment. However, whether the model can provide insights on the up-or-down regulation of adrenoreceptors remains to be determined, and many investigators believe the HDT approach should not be followed to study gravitational influences on pulmonary function in either humans or animals. It was concluded that the tail-suspended animal model had sufficient merit to study in-flight and post-flight human physiological responses and mechanisms.

  2. Reproducible computational biology experiments with SED-ML--the Simulation Experiment Description Markup Language.

    PubMed

    Waltemath, Dagmar; Adams, Richard; Bergmann, Frank T; Hucka, Michael; Kolpakov, Fedor; Miller, Andrew K; Moraru, Ion I; Nickerson, David; Sahle, Sven; Snoep, Jacky L; Le Novère, Nicolas

    2011-12-15

    The increasing use of computational simulation experiments to inform modern biological research creates new challenges to annotate, archive, share and reproduce such experiments. The recently published Minimum Information About a Simulation Experiment (MIASE) proposes a minimal set of information that should be provided to allow the reproduction of simulation experiments among users and software tools. In this article, we present the Simulation Experiment Description Markup Language (SED-ML). SED-ML encodes in a computer-readable exchange format the information required by MIASE to enable reproduction of simulation experiments. It has been developed as a community project and it is defined in a detailed technical specification and additionally provides an XML schema. The version of SED-ML described in this publication is Level 1 Version 1. It covers the description of the most frequent type of simulation experiments in the area, namely time course simulations. SED-ML documents specify which models to use in an experiment, modifications to apply on the models before using them, which simulation procedures to run on each model, what analysis results to output, and how the results should be presented. These descriptions are independent of the underlying model implementation. SED-ML is a software-independent format for encoding the description of simulation experiments; it is not specific to particular simulation tools. Here, we demonstrate that with the growing software support for SED-ML we can effectively exchange executable simulation descriptions. With SED-ML, software can exchange simulation experiment descriptions, enabling the validation and reuse of simulation experiments in different tools. Authors of papers reporting simulation experiments can make their simulation protocols available for other scientists to reproduce the results. Because SED-ML is agnostic about exact modeling language(s) used, experiments covering models from different fields of research can be accurately described and combined.

  3. The sensitivity of past and near-future lunar radio experiments to ultra-high-energy cosmic rays and neutrinos

    NASA Astrophysics Data System (ADS)

    Bray, J. D.

    2016-04-01

    Various experiments have been conducted to search for the radio emission from ultra-high-energy (UHE) particles interacting in the lunar regolith. Although they have not yielded any detections, they have been successful in establishing upper limits on the flux of these particles. I present a review of these experiments in which I re-evaluate their sensitivity to radio pulses, accounting for effects which were neglected in the original reports, and compare them with prospective near-future experiments. In several cases, I find that past experiments were substantially less sensitive than previously believed. I apply existing analytic models to determine the resulting limits on the fluxes of UHE neutrinos and cosmic rays (CRs). In the latter case, I amend the model to accurately reflect the fraction of the primary particle energy which manifests in the resulting particle cascade, resulting in a substantial improvement in the estimated sensitivity to CRs. Although these models are in need of further refinement, in particular to incorporate the effects of small-scale lunar surface roughness, their application here indicates that a proposed experiment with the LOFAR telescope would test predictions of the neutrino flux from exotic-physics models, and an experiment with a phased-array feed on a large single-dish telescope such as the Parkes radio telescope would allow the first detection of CRs with this technique, with an expected rate of one detection per 140 h.

  4. A design of experiment approach for efficient multi-parametric drug testing using a Caenorhabditis elegans model.

    PubMed

    Letizia, M C; Cornaglia, M; Tranchida, G; Trouillon, R; Gijs, M A M

    2018-01-22

    When studying the drug effectiveness towards a target model, one should distinguish the effects of the drug itself and of all the other factors that could influence the screening outcome. This comprehensive knowledge is crucial, especially when model organisms are used to study the drug effect at a systemic level, as a higher number of factors can influence the drug-testing outcome. Covering the entire experimental domain and studying the effect of the simultaneous change in several factors would require numerous experiments, which are costly and time-consuming. Therefore, a design of experiment (DoE) approach in drug-testing is emerging as a robust and efficient method to reduce the use of resources, while maximizing the knowledge of the process. Here, we used a 3-factor-Doehlert DoE to characterize the concentration-dependent effect of the drug doxycycline on the development duration of the nematode Caenorhabditis elegans. To cover the experimental space, 13 experiments were designed and performed, where different doxycycline concentrations were tested, while also varying the temperature and the food amount, which are known to influence the duration of C. elegans development. A microfluidic platform was designed to isolate and culture C. elegans larvae, while testing the doxycycline effect with full control of temperature and feeding over the entire development. Our approach allowed predicting the doxycycline effect on C. elegans development in the complete drug concentration/temperature/feeding experimental space, maximizing the understanding of the effect of this antibiotic on the C. elegans development and paving the way towards a standardized and optimized drug-testing process.

  5. World Ocean Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Clarke, R. Allyn

    1992-01-01

    The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

  6. The Pitch-Matching Ability of High School Choral Students: A Justification for Continued Direct Instruction

    ERIC Educational Resources Information Center

    Riegle, Aaron M.; Gerrity, Kevin W.

    2011-01-01

    The purpose of this study was to determine the pitch-matching ability of high school choral students. Years of piano experience, middle school performance experience, and model were considered as variables that might affect pitch-matching ability. Gender of participants was also considered when identifying the effectiveness of each model.…

  7. Effects of Practice on Task Architecture: Combined Evidence from Interference Experiments and Random-Walk Models of Decision Making

    ERIC Educational Resources Information Center

    Kamienkowski, Juan E.; Pashler, Harold; Dehaene, Stanislas; Sigman, Mariano

    2011-01-01

    Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay…

  8. Three-Level Models for Indirect Effects in School- and Class-Randomized Experiments in Education

    ERIC Educational Resources Information Center

    Pituch, Keenan A.; Murphy, Daniel L.; Tate, Richard L.

    2009-01-01

    Due to the clustered nature of field data, multi-level modeling has become commonly used to analyze data arising from educational field experiments. While recent methodological literature has focused on multi-level mediation analysis, relatively little attention has been devoted to mediation analysis when three levels (e.g., student, class,…

  9. Anxiolytic effects of lavender oil inhalation on open-field behaviour in rats.

    PubMed

    Shaw, D; Annett, J M; Doherty, B; Leslie, J C

    2007-09-01

    To establish a valid animal model of the effects of olfactory stimuli on anxiety, a series of experiments was conducted using rats in an open-field test. Throughout, effects of lavender oil were compared with the effects of chlordiazepoxide (CDP), as a reference anxiolytic with well-known effects on open-field behaviour. Rats were exposed to lavender oil (0.1-1.0 ml) for 30 min (Experiment 1) or 1h (Experiment 2) prior to open-field test and in the open field or injected with CDP (10 mg/kg i.p.). CDP had predicted effects on behaviour, and the higher doses of lavender oil had some effects on behaviour similar to those of CDP. In Experiment 3, various combinations of pre-exposure times and amounts of lavender oil were used. With sufficient exposure time and quantity of lavender the same effects were obtained as in Experiment 2. Experiment 4 demonstrated that these behavioural effects of lavender could be obtained following pre-exposure, even if no oil was present in the open-field test. In Experiments 2-4, lavender oil increased immobility. Together, these experiments suggest that lavender oil does have anxiolytic effects in the open field, but that a sedative effect can also occur at the highest doses.

  10. Uniaxial ratchetting of 316FR steel at room temperature -- Part 2. Constitutive modeling and simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ohno, N.; Abdel-Karim, M.

    2000-01-01

    Uniaxial ratchetting experiments of 316FR steel at room temperature reported in Part 1 are simulated using a new kinematic hardening model which has two kinds of dynamic recovery terms. The model, which features the capability of simulating slight opening of stress-strain hysteresis loops robustly, is formulated by furnishing the Armstrong and Frederick model with the critical state of dynamic recovery introduced by Ohno and Wang (1993). The model is then combined with a viscoplastic equation, and the resulting constitutive model is applied successfully to simulating the experiments. It is shown that for ratchetting under stress cycling with negative stress ratio,more » viscoplasticity and slight opening of hysteresis loops are effective mainly in early and subsequent cycles, respectively, whereas for ratchetting under zero-to-tension only viscoplasticity is effective.« less

  11. Tissue Modeling and Analyzing with Finite Element Method: A Review for Cranium Brain Imaging

    PubMed Central

    Yue, Xianfang; Wang, Li; Wang, Ruonan

    2013-01-01

    For the structure mechanics of human body, it is almost impossible to conduct mechanical experiments. Then the finite element model to simulate mechanical experiments has become an effective tool. By introducing several common methods for constructing a 3D model of cranial cavity, this paper carries out systematically the research on the influence law of cranial cavity deformation. By introducing the new concepts and theory to develop the 3D cranial cavity model with the finite-element method, the cranial cavity deformation process with the changing ICP can be made the proper description and reasonable explanation. It can provide reference for getting cranium biomechanical model quickly and efficiently and lay the foundation for further biomechanical experiments and clinical applications. PMID:23476630

  12. Possible Experiment for the Demonstration of Neutron Waves Interaction with Spatially Oscillating Potential

    NASA Astrophysics Data System (ADS)

    Miloi, Mădălina Mihaela; Goryunov, Semyon; Kulin, German

    2018-04-01

    A wide range of problems in neutron optics is well described by a theory based on application of the effective potential model. It was assumed that the concept of the effective potential in neutron optics have a limited region of validity and ceases to be correct in the case of the giant acceleration of a matter. To test this hypothesis a new Ultra Cold neutron experiment for the observation neutron interaction with potential structure oscillating in space was proposed. The report is focused on the model calculations of the topography of sample surface that oscillate in space. These calculations are necessary to find an optimal parameters and geometry of the planned experiment.

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Atamturktur, Sez; Unal, Cetin; Hemez, Francois

    The project proposed to provide a Predictive Maturity Framework with its companion metrics that (1) introduce a formalized, quantitative means to communicate information between interested parties, (2) provide scientifically dependable means to claim completion of Validation and Uncertainty Quantification (VU) activities, and (3) guide the decision makers in the allocation of Nuclear Energy’s resources for code development and physical experiments. The project team proposed to develop this framework based on two complimentary criteria: (1) the extent of experimental evidence available for the calibration of simulation models and (2) the sophistication of the physics incorporated in simulation models. The proposed frameworkmore » is capable of quantifying the interaction between the required number of physical experiments and degree of physics sophistication. The project team has developed this framework and implemented it with a multi-scale model for simulating creep of a core reactor cladding. The multi-scale model is composed of the viscoplastic self-consistent (VPSC) code at the meso-scale, which represents the visco-plastic behavior and changing properties of a highly anisotropic material and a Finite Element (FE) code at the macro-scale to represent the elastic behavior and apply the loading. The framework developed takes advantage of the transparency provided by partitioned analysis, where independent constituent codes are coupled in an iterative manner. This transparency allows model developers to better understand and remedy the source of biases and uncertainties, whether they stem from the constituents or the coupling interface by exploiting separate-effect experiments conducted within the constituent domain and integral-effect experiments conducted within the full-system domain. The project team has implemented this procedure with the multi- scale VPSC-FE model and demonstrated its ability to improve the predictive capability of the model. Within this framework, the project team has focused on optimizing resource allocation for improving numerical models through further code development and experimentation. Related to further code development, we have developed a code prioritization index (CPI) for coupled numerical models. CPI is implemented to effectively improve the predictive capability of the coupled model by increasing the sophistication of constituent codes. In relation to designing new experiments, we investigated the information gained by the addition of each new experiment used for calibration and bias correction of a simulation model. Additionally, the variability of ‘information gain’ through the design domain has been investigated in order to identify the experiment settings where maximum information gain occurs and thus guide the experimenters in the selection of the experiment settings. This idea was extended to evaluate the information gain from each experiment can be improved by intelligently selecting the experiments, leading to the development of the Batch Sequential Design (BSD) technique. Additionally, we evaluated the importance of sufficiently exploring the domain of applicability in experiment-based validation of high-consequence modeling and simulation by developing a new metric to quantify coverage. This metric has also been incorporated into the design of new experiments. Finally, we have proposed a data-aware calibration approach for the calibration of numerical models. This new method considers the complexity of a numerical model (the number of parameters to be calibrated, parameter uncertainty, and form of the model) and seeks to identify the number of experiments necessary to calibrate the model based on the level of sophistication of the physics. The final component in the project team’s work to improve model calibration and validation methods is the incorporation of robustness to non-probabilistic uncertainty in the input parameters. This is an improvement to model validation and uncertainty quantification stemming beyond the originally proposed scope of the project. We have introduced a new metric for incorporating the concept of robustness into experiment-based validation of numerical models. This project has accounted for the graduation of two Ph.D. students (Kendra Van Buren and Josh Hegenderfer) and two M.S. students (Matthew Egeberg and Parker Shields). One of the doctoral students is now working in the nuclear engineering field and the other one is a post-doctoral fellow at the Los Alamos National Laboratory. Additionally, two more Ph.D. students (Garrison Stevens and Tunc Kulaksiz) who are working towards graduation have been supported by this project.« less

  14. Where does the carbon go? A model–data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites

    PubMed Central

    De Kauwe, Martin G; Medlyn, Belinda E; Zaehle, Sönke; Walker, Anthony P; Dietze, Michael C; Wang, Ying-Ping; Luo, Yiqi; Jain, Atul K; El-Masri, Bassil; Hickler, Thomas; Wårlind, David; Weng, Ensheng; Parton, William J; Thornton, Peter E; Wang, Shusen; Prentice, I Colin; Asao, Shinichi; Smith, Benjamin; McCarthy, Heather R; Iversen, Colleen M; Hanson, Paul J; Warren, Jeffrey M; Oren, Ram; Norby, Richard J

    2014-01-01

    Elevated atmospheric CO2 concentration (eCO2) has the potential to increase vegetation carbon storage if increased net primary production causes increased long-lived biomass. Model predictions of eCO2 effects on vegetation carbon storage depend on how allocation and turnover processes are represented. We used data from two temperate forest free-air CO2 enrichment (FACE) experiments to evaluate representations of allocation and turnover in 11 ecosystem models. Observed eCO2 effects on allocation were dynamic. Allocation schemes based on functional relationships among biomass fractions that vary with resource availability were best able to capture the general features of the observations. Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes. Few models represent turnover processes mechanistically and there was wide variation in predictions of tissue lifespan. Consequently, models did not perform well at predicting eCO2 effects on vegetation carbon storage. Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters. Data from intensively studied ecosystem manipulation experiments are invaluable for constraining models and we recommend that such experiments should attempt to fully quantify carbon, water and nutrient budgets. PMID:24844873

  15. Maximally Expressive Modeling

    NASA Technical Reports Server (NTRS)

    Jaap, John; Davis, Elizabeth; Richardson, Lea

    2004-01-01

    Planning and scheduling systems organize tasks into a timeline or schedule. Tasks are logically grouped into containers called models. Models are a collection of related tasks, along with their dependencies and requirements, that when met will produce the desired result. One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed; the information sought is at the cutting edge of scientific endeavor; and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a maximally expressive modeling schema.

  16. Colloid-Facilitated Transport of 137Cs in Fracture-Fill Material. Experiments and Modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dittrich, Timothy M.; Reimus, Paul William

    2015-10-29

    In this study, we demonstrate how a combination of batch sorption/desorption experiments and column transport experiments were used to effectively parameterize a model describing the colloid-facilitated transport of Cs in the Grimsel granodiorite/FFM system. Cs partition coefficient estimates onto both the colloids and the stationary media obtained from the batch experiments were used as initial estimates of partition coefficients in the column experiments, and then the column experiment results were used to obtain refined estimates of the number of different sorption sites and the adsorption and desorption rate constants of the sites. The desorption portion of the column breakthrough curvesmore » highlighted the importance of accounting for adsorption-desorption hysteresis (or a very nonlinear adsorption isotherm) of the Cs on the FFM in the model, and this portion of the breakthrough curves also dictated that there be at least two different types of sorption sites on the FFM. In the end, the two-site model parameters estimated from the column experiments provided excellent matches to the batch adsorption/desorption data, which provided a measure of assurance in the validity of the model.« less

  17. Psychiatry's next top model: cause for a re-think on drug models of psychosis and other psychiatric disorders.

    PubMed

    Carhart-Harris, R L; Brugger, S; Nutt, D J; Stone, J M

    2013-09-01

    Despite the widespread application of drug modelling in psychiatric research, the relative value of different models has never been formally compared in the same analysis. Here we compared the effects of five drugs (cannabis, psilocybin, amphetamine, ketamine and alcohol) in relation to psychiatric symptoms in a two-part subjective analysis. In the first part, mental health professionals associated statements referring to specific experiences, for example 'I don't bother to get out of bed', to one or more psychiatric symptom clusters, for example depression and negative psychotic symptoms. This measured the specificity of an experience for a particular disorder. In the second part, individuals with personal experience with each of the above-listed drugs were asked how reliably each drug produced the experiences listed in part 1, both acutely and sub-acutely. Part 1 failed to find any experiences that were specific for negative or cognitive psychotic symptoms over depression. The best model of positive symptoms was psilocybin and the best models overall were the acute alcohol and amphetamine models of mania. These results challenge current assumptions about drug models and motivate further research on this understudied area.

  18. Heterogeneity and scaling land-atmospheric water and energy fluxes in climate systems

    NASA Technical Reports Server (NTRS)

    Wood, Eric F.

    1993-01-01

    The effects of small-scale heterogeneity in land surface characteristics on the large-scale fluxes of water and energy in land-atmosphere system has become a central focus of many of the climatology research experiments. The acquisition of high resolution land surface data through remote sensing and intensive land-climatology field experiments (like HAPEX and FIFE) has provided data to investigate the interactions between microscale land-atmosphere interactions and macroscale models. One essential research question is how to account for the small scale heterogeneities and whether 'effective' parameters can be used in the macroscale models. To address this question of scaling, three modeling experiments were performed and are reviewed in the paper. The first is concerned with the aggregation of parameters and inputs for a terrestrial water and energy balance model. The second experiment analyzed the scaling behavior of hydrologic responses during rain events and between rain events. The third experiment compared the hydrologic responses from distributed models with a lumped model that uses spatially constant inputs and parameters. The results show that the patterns of small scale variations can be represented statistically if the scale is larger than a representative elementary area scale, which appears to be about 2 - 3 times the correlation length of the process. For natural catchments this appears to be about 1 - 2 sq km. The results concerning distributed versus lumped representations are more complicated. For conditions when the processes are nonlinear, then lumping results in biases; otherwise a one-dimensional model based on 'equivalent' parameters provides quite good results. Further research is needed to fully understand these conditions.

  19. Gene–Environment Correlation: Difficulties and a Natural Experiment–Based Strategy

    PubMed Central

    Li, Jiang; Liu, Hexuan; Guo, Guang

    2013-01-01

    Objectives. We explored how gene–environment correlations can result in endogenous models, how natural experiments can protect against this threat, and if unbiased estimates from natural experiments are generalizable to other contexts. Methods. We compared a natural experiment, the College Roommate Study, which measured genes and behaviors of college students and their randomly assigned roommates in a southern public university, with observational data from the National Longitudinal Study of Adolescent Health in 2008. We predicted exposure to exercising peers using genetic markers and estimated environmental effects on alcohol consumption. A mixed-linear model estimated an alcohol consumption variance that was attributable to genetic markers and across peer environments. Results. Peer exercise environment was associated with respondent genotype in observational data, but not in the natural experiment. The effects of peer drinking and presence of a general gene–environment interaction were similar between data sets. Conclusions. Natural experiments, like random roommate assignment, could protect against potential bias introduced by gene–environment correlations. When combined with representative observational data, unbiased and generalizable causal effects could be estimated. PMID:23927502

  20. Modeling the effects of high-G stress on pilots in a tracking task

    NASA Technical Reports Server (NTRS)

    Korn, J.; Kleinman, D. L.

    1978-01-01

    Air-to-air tracking experiments were conducted at the Aerospace Medical Research Laboratories using both fixed and moving base dynamic environment simulators. The obtained data, which includes longitudinal error of a simulated air-to-air tracking task as well as other auxiliary variables, was analyzed using an ensemble averaging method. In conjunction with these experiments, the optimal control model is applied to model a human operator under high-G stress.

  1. Modeling nuclear processes by Simulink

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rashid, Nahrul Khair Alang Md, E-mail: nahrul@iium.edu.my

    2015-04-29

    Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox softwaremore » that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples.« less

  2. Field warming experiments shed light on the wheat yield response to temperature in China

    PubMed Central

    Zhao, Chuang; Piao, Shilong; Huang, Yao; Wang, Xuhui; Ciais, Philippe; Huang, Mengtian; Zeng, Zhenzhong; Peng, Shushi

    2016-01-01

    Wheat growth is sensitive to temperature, but the effect of future warming on yield is uncertain. Here, focusing on China, we compiled 46 observations of the sensitivity of wheat yield to temperature change (SY,T, yield change per °C) from field warming experiments and 102 SY,T estimates from local process-based and statistical models. The average SY,T from field warming experiments, local process-based models and statistical models is −0.7±7.8(±s.d.)% per °C, −5.7±6.5% per °C and 0.4±4.4% per °C, respectively. Moreover, SY,T is different across regions and warming experiments indicate positive SY,T values in regions where growing-season mean temperature is low, and water supply is not limiting, and negative values elsewhere. Gridded crop model simulations from the Inter-Sectoral Impact Model Intercomparison Project appear to capture the spatial pattern of SY,T deduced from warming observations. These results from local manipulative experiments could be used to improve crop models in the future. PMID:27853151

  3. An integrated model for the effects of self-reflection and clinical experiential learning on clinical nursing performance in nursing students: A longitudinal study.

    PubMed

    Pai, Hsiang-Chu

    2016-10-01

    The use of clinical simulation in undergraduate nursing programs in Taiwan has gradually increased over the past 5years. Previous research has shown that students' experience of anxiety during simulated laboratory sessions influences their self-reflection and learning effectiveness. Thus, further study that tracks what influences students' clinical performance in actual clinical sites is vital. The aim of the study is to develop an integrated model that considers the associations among anxiety, self-reflection, and learning effectiveness and to understand how this model applies to student nurses' clinical performance while on clinical placement. This study used a correlational and longitudinal study design. The 80 nursing students, who ranged in age from 19 to 21 (mean=20.38, SD=0.56), were recruited from a nursing school in southern Taiwan. Data were collected during three phases of implementation using four questionnaires. During the first phase, the State-Trait Anxiety Inventory (STAI), Simulation Learning Effectiveness Scale (SLES), and Self-Reflection and Insight Scale (SRIS) were used after students completed the simulation course in the school simulation laboratory. Nursing students also completed the Holistic Nursing Competence Scale at 2months (Phase 2) and 4months (Phase 3) after clinical practice experience. In Phase 3, students again completed the STAI and SRIS. Partial least squares (PLS), a structural equation modeling (SEM) procedure, was used to test the research model. The findings showed that: (1) at the start of the simulation laboratory, anxiety had a significant negative effect on students' simulation learning effectiveness (SLE; β=-0.14, p<0.05) and on self-reflection with insight (SRI; β=-0.52, p<0.01). Self-reflection also had a significant positive effect on simulation learning effectiveness (β=0.37, p<0.01). Anxiety had a significant negative effect on students' nursing competence during the first 2months of practice in a clinical nursing site (β=-0.20, p<0.01). Simulation learning effectiveness and self-reflection and insight also had a significant positive effect on nursing competence during the first 2months of practice in a clinical site (β=0.13; β=0.16, p<0.05), respectively; and (2) when students practice in a clinical setting, their previous experience of nursing competence during the first 2months of clinical care and their self-reflection and insight have a significant positive effect on their 4-month nursing competence (β=0.58; β=0.27, p<0.01). Anxiety, however, had a negative effect on 4-month nursing competence but not significantly. Overall, 41% of the variance in clinical nursing performance was accounted for by the variables in the integrated model. This study highlights that self-reflection with insight and clinical experience may help students to deflect anxiety that may influence the development of clinical competence. Of note is that real-life clinical experience has a stronger effect on enhancing clinical performance than does a simulation experience. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A Theory of Age-Dependent Mutation and Senescence

    PubMed Central

    Moorad, Jacob A.; Promislow, Daniel E. L.

    2008-01-01

    Laboratory experiments show us that the deleterious character of accumulated novel age-specific mutations is reduced and made less variable with increased age. While theories of aging predict that the frequency of deleterious mutations at mutation–selection equilibrium will increase with the mutation's age of effect, they do not account for these age-related changes in the distribution of de novo mutational effects. Furthermore, no model predicts why this dependence of mutational effects upon age exists. Because the nature of mutational distributions plays a critical role in shaping patterns of senescence, we need to develop aging theory that explains and incorporates these effects. Here we propose a model that explains the age dependency of mutational effects by extending Fisher's geometrical model of adaptation to include a temporal dimension. Using a combination of simple analytical arguments and simulations, we show that our model predicts age-specific mutational distributions that are consistent with observations from mutation-accumulation experiments. Simulations show us that these age-specific mutational effects may generate patterns of senescence at mutation–selection equilibrium that are consistent with observed demographic patterns that are otherwise difficult to explain. PMID:18660535

  5. A general model-based design of experiments approach to achieve practical identifiability of pharmacokinetic and pharmacodynamic models.

    PubMed

    Galvanin, Federico; Ballan, Carlo C; Barolo, Massimiliano; Bezzo, Fabrizio

    2013-08-01

    The use of pharmacokinetic (PK) and pharmacodynamic (PD) models is a common and widespread practice in the preliminary stages of drug development. However, PK-PD models may be affected by structural identifiability issues intrinsically related to their mathematical formulation. A preliminary structural identifiability analysis is usually carried out to check if the set of model parameters can be uniquely determined from experimental observations under the ideal assumptions of noise-free data and no model uncertainty. However, even for structurally identifiable models, real-life experimental conditions and model uncertainty may strongly affect the practical possibility to estimate the model parameters in a statistically sound way. A systematic procedure coupling the numerical assessment of structural identifiability with advanced model-based design of experiments formulations is presented in this paper. The objective is to propose a general approach to design experiments in an optimal way, detecting a proper set of experimental settings that ensure the practical identifiability of PK-PD models. Two simulated case studies based on in vitro bacterial growth and killing models are presented to demonstrate the applicability and generality of the methodology to tackle model identifiability issues effectively, through the design of feasible and highly informative experiments.

  6. Neutral null models for diversity in serial transfer evolution experiments.

    PubMed

    Harpak, Arbel; Sella, Guy

    2014-09-01

    Evolution experiments with microorganisms coupled with genome-wide sequencing now allow for the systematic study of population genetic processes under a wide range of conditions. In learning about these processes in natural, sexual populations, neutral models that describe the behavior of diversity and divergence summaries have played a pivotal role. It is therefore natural to ask whether neutral models, suitably modified, could be useful in the context of evolution experiments. Here, we introduce coalescent models for polymorphism and divergence under the most common experimental evolution assay, a serial transfer experiment. This relatively simple setting allows us to address several issues that could affect diversity patterns in evolution experiments, whether selection is operating or not: the transient behavior of neutral polymorphism in an experiment beginning from a single clone, the effects of randomness in the timing of cell division and noisiness in population size in the dilution stage. In our analyses and discussion, we emphasize the implications for experiments aimed at measuring diversity patterns and making inferences about population genetic processes based on these measurements. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  7. The not-so-sterile 4th neutrino: constraints on new gauge interactions from neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Kopp, Joachim; Welter, Johannes

    2014-12-01

    Sterile neutrino models with new gauge interactions in the sterile sector are phenomenologically interesting since they can lead to novel effects in neutrino oscillation experiments, in cosmology and in dark matter detectors, possibly even explaining some of the observed anomalies in these experiments. Here, we use data from neutrino oscillation experiments, in particular from MiniBooNE, MINOS and solar neutrino experiments, to constrain such models. We focus in particular on the case where the sterile sector gauge boson A ' couples also to Standard Model particles (for instance to the baryon number current) and thus induces a large Mikheyev-Smirnov-Wolfenstein potential. For eV-scale sterile neutrinos, we obtain strong constraints especially from MINOS, which restricts the strength of the new interaction to be less than ˜ 10 times that of the Standard Model weak interaction unless active-sterile neutrino mixing is very small (sin2 θ 24 ≲ 10-3). This rules out gauge forces large enough to affect short-baseline experiments like MiniBooNE and it imposes nontrivial constraints on signals from sterile neutrino scattering in dark matter experiments.

  8. Attractor Dynamics and Semantic Neighborhood Density: Processing Is Slowed by Near Neighbors and Speeded by Distant Neighbors

    PubMed Central

    Mirman, Daniel; Magnuson, James S.

    2008-01-01

    The authors investigated semantic neighborhood density effects on visual word processing to examine the dynamics of activation and competition among semantic representations. Experiment 1 validated feature-based semantic representations as a basis for computing semantic neighborhood density and suggested that near and distant neighbors have opposite effects on word processing. Experiment 2 confirmed these results: Word processing was slower for dense near neighborhoods and faster for dense distant neighborhoods. Analysis of a computational model showed that attractor dynamics can produce this pattern of neighborhood effects. The authors argue for reconsideration of traditional models of neighborhood effects in terms of attractor dynamics, which allow both inhibitory and facilitative effects to emerge. PMID:18194055

  9. FESTER: a propagation experiment, overview and first results

    NASA Astrophysics Data System (ADS)

    Eisele, Christian; Seiffer, Dirk Peter; Stein, Karin; Sucher, Erik; Gunter, Willem H.; February, Faith; Vrahimis, George; Wainman, Carl; Maritz, Benita; Koago, Mokete S.; van Eijk, Alexander M. J.; van Iersel, Miranda; Cohen, Leo H.; van Binsbergen, Sven A.; Heemskerk, H. J. M. (Eric); Sternberg, Armin; Schulte, Helmut; van Rheenen, Arthur D.; Brenthagen, Erik; Thomassen, Jan B.; Griffith, Derek

    2016-10-01

    A long term field trial called FESTER (First European South African Transmission Experiment) has been conducted by an international collaboration of research organizations during the course of almost one year at False Bay, South Africa. Main objectives of the experiment are a better insight into atmospherical effects on propagation of optical radiation, a deeper understanding of the effects of (marine) aerosols on transmission, and the connection of the mentioned effects to the general meteorological and oceanographic conditions/parameters. Modelling of wakes and possible infrared-radar synergy effects are further points of interest. The duration of one year ensures the coverage of most of the relevant meteorological conditions during the different seasons. While some measurements have been performed by permanent installations, others have been performed during intensive observation periods (IOP). These IOPs took place every two to three months to ensure seasonal changes. The IOPs lasted two weeks. We will give an overview of the general layout of the experiment and report on first results. An outlook on the planned analysis of the acquired data, which includes linkage to the Weather Research and Forecasting model (WRF), will be given.

  10. Dynamic and static equilibrium sea level effects of Greenland Ice Sheet melt: An assessment of partially-coupled idealized water hosing experiments (Invited)

    NASA Astrophysics Data System (ADS)

    Kopp, R. E.; Mitrovica, J. X.; Griffies, S. M.; Yin, J.; Hay, C. C.; Stouffer, R. J.

    2010-12-01

    Regional sea level can deviate from mean global sea level because of both dynamic sea level (DSL) effects, resulting from oceanic and atmospheric circulation and temperature and salinity distributions, and changes in the static equilibrium (SE) sea level configuration, produced by the gravitational, elastic, and rotational effects of mass redistribution. Both effects will contribute to future sea level change, but because they are studied by two different subdisciplines -- climate modeling and glacial rebound modeling -- projections that attempt to combine both have to date been scarce. To compare their magnitude, we simulated the effects of Greenland Ice Sheet (GIS) melt by conducting idealized North Atlantic "water-hosing" experiments in a climate model unidirectionally coupled to a SE sea level model. At current rates of GIS melt, freshwater hosing experiments in fully coupled atmosphere-ocean general circulation models (AOGCMs) do not yield clear DSL trends but do generate DSL variability; comparing that variability to expected static equilibrium "fingerprints" suggests that at least about 40 years of observations are needed to detect the "fingerprints" of ice sheet melt at current Greenland melt rates of about 0.3 mm equivalent sea level (esl)/year. Accelerated melt rates of about 2--6 mm esl/y, as may occur later in the century, should be detectable above background DSL variability within less than a decade of their onset. At these higher melt rates, AOGCMs do yield clear DSL trends. In the GFDL CM 2.1 model, DSL trends are strongest in the western North Atlantic, while SE effects come to dominate in most of the ocean when melt exceeds about 20 cm esl.

  11. Effects of Precipitation on Ocean Mixed-Layer Temperature and Salinity as Simulated in a 2-D Coupled Ocean-Cloud Resolving Atmosphere Model

    NASA Technical Reports Server (NTRS)

    Li, Xiaofan; Sui, C.-H.; Lau, K-M.; Adamec, D.

    1999-01-01

    A two-dimensional coupled ocean-cloud resolving atmosphere model is used to investigate possible roles of convective scale ocean disturbances induced by atmospheric precipitation on ocean mixed-layer heat and salt budgets. The model couples a cloud resolving model with an embedded mixed layer-ocean circulation model. Five experiment are performed under imposed large-scale atmospheric forcing in terms of vertical velocity derived from the TOGA COARE observations during a selected seven-day period. The dominant variability of mixed-layer temperature and salinity are simulated by the coupled model with imposed large-scale forcing. The mixed-layer temperatures in the coupled experiments with 1-D and 2-D ocean models show similar variations when salinity effects are not included. When salinity effects are included, however, differences in the domain-mean mixed-layer salinity and temperature between coupled experiments with 1-D and 2-D ocean models could be as large as 0.3 PSU and 0.4 C respectively. Without fresh water effects, the nocturnal heat loss over ocean surface causes deep mixed layers and weak cooling rates so that the nocturnal mixed-layer temperatures tend to be horizontally-uniform. The fresh water flux, however, causes shallow mixed layers over convective areas while the nocturnal heat loss causes deep mixed layer over convection-free areas so that the mixed-layer temperatures have large horizontal fluctuations. Furthermore, fresh water flux exhibits larger spatial fluctuations than surface heat flux because heavy rainfall occurs over convective areas embedded in broad non-convective or clear areas, whereas diurnal signals over whole model areas yield high spatial correlation of surface heat flux. As a result, mixed-layer salinities contribute more to the density differences than do mixed-layer temperatures.

  12. Pore-scale and continuum simulations of solute transport micromodel benchmark experiments

    DOE PAGES

    Oostrom, M.; Mehmani, Y.; Romero-Gomez, P.; ...

    2014-06-18

    Four sets of nonreactive solute transport experiments were conducted with micromodels. Three experiments with one variable, i.e., flow velocity, grain diameter, pore-aspect ratio, and flow-focusing heterogeneity were in each set. The data sets were offered to pore-scale modeling groups to test their numerical simulators. Each set consisted of two learning experiments, for which our results were made available, and one challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the transverse dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing,more » and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice Boltzmann (LB) approach, and one used a computational fluid dynamics (CFD) technique. Furthermore, we used the learning experiments, by the PN models, to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used the learning experiments to appropriately discretize the spatial grid representations. For the continuum modeling, the required dispersivity input values were estimated based on published nonlinear relations between transverse dispersion coefficients and Peclet number. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values, resulting in reduced dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models, which account for the micromodel geometry and underlying flow and transport physics, needed up to several days on supercomputers to resolve the more complex problems.« less

  13. Evaluation of work stress, turnover intention, work experience, and satisfaction with preceptors of new graduate nurses using a 10-minute preceptor model.

    PubMed

    Hu, Yi-Chun; Chen, Su-Ru; Chen, I-Hui; Shen, Hsi-Che; Lin, Yen-Kuang; Chang, Wen-Yin

    2015-06-01

    Preparing new graduate nurses (NGNs) to achieve standards of nursing competence is challenging; therefore, this study developed and evaluated the effects of a 10-minute preceptor (10MP) model for assisting NGNs in their professional development and increasing their retention in hospitals. A repeated-measures design study, with an intervention and a two-group comparison, was conducted. A total of 107 NGNs participated in the study. At day 7, work stress and work experience were moderately high for the NGNs in both the 10MP and traditional preceptor model (TPM) groups. The preceptorship program showed significant differences between groups (p = 0.001) regarding work stress at months 2 and 3 and work experience at months 1, 2, and 3. The 10MP group reported lower turnover intention and higher satisfaction with the preceptors than the TPM group. The 10MP model is effective at improving training outcomes and facilitating the professional development of NGNs. Copyright 2015, SLACK Incorporated.

  14. The effects of nutrition labeling on consumer food choice: a psychological experiment and computational model.

    PubMed

    Helfer, Peter; Shultz, Thomas R

    2014-12-01

    The widespread availability of calorie-dense food is believed to be a contributing cause of an epidemic of obesity and associated diseases throughout the world. One possible countermeasure is to empower consumers to make healthier food choices with useful nutrition labeling. An important part of this endeavor is to determine the usability of existing and proposed labeling schemes. Here, we report an experiment on how four different labeling schemes affect the speed and nutritional value of food choices. We then apply decision field theory, a leading computational model of human decision making, to simulate the experimental results. The psychology experiment shows that quantitative, single-attribute labeling schemes have greater usability than multiattribute and binary ones, and that they remain effective under moderate time pressure. The computational model simulates these psychological results and provides explanatory insights into them. This work shows how experimental psychology and computational modeling can contribute to the evaluation and improvement of nutrition-labeling schemes. © 2014 New York Academy of Sciences.

  15. Understanding the shock and detonation response of high explosives at the continuum and meso scales

    NASA Astrophysics Data System (ADS)

    Handley, C. A.; Lambourn, B. D.; Whitworth, N. J.; James, H. R.; Belfield, W. J.

    2018-03-01

    The shock and detonation response of high explosives has been an active research topic for more than a century. In recent years, high quality data from experiments using embedded gauges and other diagnostic techniques have inspired the development of a range of new high-fidelity computer models for explosives. The experiments and models have led to new insights, both at the continuum scale applicable to most shock and detonation experiments, and at the mesoscale relevant to hotspots and burning within explosive microstructures. This article reviews the continuum and mesoscale models, and their application to explosive phenomena, gaining insights to aid future model development and improved understanding of the physics of shock initiation and detonation propagation. In particular, it is argued that "desensitization" and the effect of porosity on high explosives can both be explained by the combined effect of thermodynamics and hydrodynamics, rather than the traditional hotspot-based explanations linked to pressure-dependent reaction rates.

  16. Explaining reported puma-related behaviors and behavioral intentions among northern Arizona residents

    USGS Publications Warehouse

    Mattson, David J.; Ruther, Elizabeth J.

    2012-01-01

    Management of pumas in the American West is typified by conflict among stakeholders plausibly rooted in life experiences and worldviews. We used a mail questionnaire to assess demographics, nature-views, puma-related life experiences and behaviors, and support for puma-related policies among residents of northern Arizona. Data from the questionnaire (n = 693 respondents) were used to model behaviors and support for policies. Compared to models based on nature-views and life experiences, those based on demographics had virtually no support from the data. The Utilitarian/Dominionistic nature-view had the strongest effect of any variable in six of seven models, and was associated with firearms and opposition to policies that would limit killing pumas. The Humanistic/Moralistic nature-view was positively associated with non-lethal behaviors and policies in five models. Gender had the strongest effect of any demographic variable. Compared to demographics alone, our results suggest that worldviews provide a more meaningful explanation of reported human behaviors and behavioral intentions regarding pumas.

  17. Decision making under time pressure, modeled in a prospect theory framework.

    PubMed

    Young, Diana L; Goodie, Adam S; Hall, Daniel B; Wu, Eric

    2012-07-01

    The current research examines the effects of time pressure on decision behavior based on a prospect theory framework. In Experiments 1 and 2, participants estimated certainty equivalents for binary gains-only bets in the presence or absence of time pressure. In Experiment 3, participants assessed comparable bets that were framed as losses. Data were modeled to establish psychological mechanisms underlying decision behavior. In Experiments 1 and 2, time pressure led to increased risk attractiveness, but no significant differences emerged in either probability discriminability or outcome utility. In Experiment 3, time pressure reduced probability discriminability, which was coupled with severe risk-seeking behavior for both conditions in the domain of losses. No significant effects of control over outcomes were observed. Results provide qualified support for theories that suggest increased risk-seeking for gains under time pressure.

  18. Decision making under time pressure, modeled in a prospect theory framework

    PubMed Central

    Young, Diana L.; Goodie, Adam S.; Hall, Daniel B.; Wu, Eric

    2012-01-01

    The current research examines the effects of time pressure on decision behavior based on a prospect theory framework. In Experiments 1 and 2, participants estimated certainty equivalents for binary gains-only bets in the presence or absence of time pressure. In Experiment 3, participants assessed comparable bets that were framed as losses. Data were modeled to establish psychological mechanisms underlying decision behavior. In Experiments 1 and 2, time pressure led to increased risk attractiveness, but no significant differences emerged in either probability discriminability or outcome utility. In Experiment 3, time pressure reduced probability discriminability, which was coupled with severe risk-seeking behavior for both conditions in the domain of losses. No significant effects of control over outcomes were observed. Results provide qualified support for theories that suggest increased risk-seeking for gains under time pressure. PMID:22711977

  19. Effect of Initial Conditions on Reproducibility of Scientific Research

    PubMed Central

    Djulbegovic, Benjamin; Hozo, Iztok

    2014-01-01

    Background: It is estimated that about half of currently published research cannot be reproduced. Many reasons have been offered as explanations for failure to reproduce scientific research findings- from fraud to the issues related to design, conduct, analysis, or publishing scientific research. We also postulate a sensitive dependency on initial conditions by which small changes can result in the large differences in the research findings when attempted to be reproduced at later times. Methods: We employed a simple logistic regression equation to model the effect of covariates on the initial study findings. We then fed the input from the logistic equation into a logistic map function to model stability of the results in repeated experiments over time. We illustrate the approach by modeling effects of different factors on the choice of correct treatment. Results: We found that reproducibility of the study findings depended both on the initial values of all independent variables and the rate of change in the baseline conditions, the latter being more important. When the changes in the baseline conditions vary by about 3.5 to about 4 in between experiments, no research findings could be reproduced. However, when the rate of change between the experiments is ≤2.5 the results become highly predictable between the experiments. Conclusions: Many results cannot be reproduced because of the changes in the initial conditions between the experiments. Better control of the baseline conditions in-between the experiments may help improve reproducibility of scientific findings. PMID:25132705

  20. Effect of initial conditions on reproducibility of scientific research.

    PubMed

    Djulbegovic, Benjamin; Hozo, Iztok

    2014-06-01

    It is estimated that about half of currently published research cannot be reproduced. Many reasons have been offered as explanations for failure to reproduce scientific research findings- from fraud to the issues related to design, conduct, analysis, or publishing scientific research. We also postulate a sensitive dependency on initial conditions by which small changes can result in the large differences in the research findings when attempted to be reproduced at later times. We employed a simple logistic regression equation to model the effect of covariates on the initial study findings. We then fed the input from the logistic equation into a logistic map function to model stability of the results in repeated experiments over time. We illustrate the approach by modeling effects of different factors on the choice of correct treatment. We found that reproducibility of the study findings depended both on the initial values of all independent variables and the rate of change in the baseline conditions, the latter being more important. When the changes in the baseline conditions vary by about 3.5 to about 4 in between experiments, no research findings could be reproduced. However, when the rate of change between the experiments is ≤2.5 the results become highly predictable between the experiments. Many results cannot be reproduced because of the changes in the initial conditions between the experiments. Better control of the baseline conditions in-between the experiments may help improve reproducibility of scientific findings.

  1. Modeled interactive effects of precipitation, temperature, and [CO2] on ecosystem carbon and water dynamics in different climatic zones

    Treesearch

    Yiqi Luo; Dieter Gerten; Guerric Le Maire; William J. Parton; Ensheng Weng; Xuhui Zhou; Cindy Keough; Claus Beier; Philippe Ciais; Wolfgang Cramer; Jeffrey S. Dukes; Bridget Emmett; Paul J. Hanson; Alan Knapp; Sune Linder; Dan Nepstad; Lindsey. Rustad

    2008-01-01

    Interactive effects of multiple global change factors on ecosystem processes are complex. It is relatively expensive to explore those interactions in manipulative experiments. We conducted a modeling analysis to identify potentially important interactions and to stimulate hypothesis formulation for experimental research. Four models were used to quantify interactive...

  2. The effects of the canopy created velocity inflection in the wake development

    NASA Astrophysics Data System (ADS)

    Agafonova, O.; Avramenko, A.; Chaudhari, A.; Hellsten, A.

    2016-06-01

    The aim of this paper is to study the effects of forest on the turbine wakes. Initially, the ACL (actuator line) model as well as a Canopy model are validated with the experiments separately. The models are further applied to simulate the flow over two wind turbines in a row located within the forest.

  3. Detection of botulinum toxin types A, B, E, and F activity using the quail embryo

    USDA-ARS?s Scientific Manuscript database

    We recently demonstrated an effective new model for the detection of botulinum toxin type A using quail embryos in place of the mouse model. These experiments demonstrated that the Japanese quail embryo at 15 days of incubation was an effective vertebrate animal model to detect the activity of botu...

  4. Heavy doping effects in high efficiency silicon solar cells

    NASA Technical Reports Server (NTRS)

    Lindholm, F. A.; Neugroschel, A.; Landsberg, P. T.; San, C. T.

    1984-01-01

    A model for bandgap shrinkage in semiconductors is developed and applied to silicon. A survey of earlier experiments, and of new ones, give an agreement between the model and experiments on n- and p-type silicon which is good as far as transport measurements in the 300 K range. The discrepancies between theory and experiment are no worse than the discrepancies between the experimental results of various authors. It also gives a good account of recent, optical determinations of band gap shrinkage at 5 K.

  5. A mechanical model of bacteriophage DNA ejection

    NASA Astrophysics Data System (ADS)

    Arun, Rahul; Ghosal, Sandip

    2017-08-01

    Single molecule experiments on bacteriophages show an exponential scaling for the dependence of mobility on the length of DNA within the capsid. It has been suggested that this could be due to the ;capstan mechanism; - the exponential amplification of friction forces that result when a rope is wound around a cylinder as in a ship's capstan. Here we describe a desktop experiment that illustrates the effect. Though our model phage is a million times larger, it exhibits the same scaling observed in single molecule experiments.

  6. Heavy-Ion Microbeam Fault Injection into SRAM-Based FPGA Implementations of Cryptographic Circuits

    NASA Astrophysics Data System (ADS)

    Li, Huiyun; Du, Guanghua; Shao, Cuiping; Dai, Liang; Xu, Guoqing; Guo, Jinlong

    2015-06-01

    Transistors hit by heavy ions may conduct transiently, thereby introducing transient logic errors. Attackers can exploit these abnormal behaviors and extract sensitive information from the electronic devices. This paper demonstrates an ion irradiation fault injection attack experiment into a cryptographic field-programmable gate-array (FPGA) circuit. The experiment proved that the commercial FPGA chip is vulnerable to low-linear energy transfer carbon irradiation, and the attack can cause the leakage of secret key bits. A statistical model is established to estimate the possibility of an effective fault injection attack on cryptographic integrated circuits. The model incorporates the effects from temporal, spatial, and logical probability of an effective attack on the cryptographic circuits. The rate of successful attack calculated from the model conforms well to the experimental results. This quantitative success rate model can help evaluate security risk for designers as well as for the third-party assessment organizations.

  7. Probing spontaneous wave-function collapse with entangled levitating nanospheres

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Zhang, Tiancai; Li, Jie

    2017-01-01

    Wave-function collapse models are considered to be the modified theories of standard quantum mechanics at the macroscopic level. By introducing nonlinear stochastic terms in the Schrödinger equation, these models (different from standard quantum mechanics) predict that it is fundamentally impossible to prepare macroscopic systems in macroscopic superpositions. The validity of these models can only be examined by experiments, and hence efficient protocols for these kinds of experiments are greatly needed. Here we provide a protocol that is able to probe the postulated collapse effect by means of the entanglement of the center-of-mass motion of two nanospheres optically trapped in a Fabry-Pérot cavity. We show that the collapse noise results in a large reduction of the steady-state entanglement, and the entanglement, with and without the collapse effect, shows distinguishable scalings with certain system parameters, which can be used to determine unambiguously the effect of these models.

  8. Primate social attention: Species differences and effects of individual experience in humans, great apes, and macaques.

    PubMed

    Kano, Fumihiro; Shepherd, Stephen V; Hirata, Satoshi; Call, Josep

    2018-01-01

    When viewing social scenes, humans and nonhuman primates focus on particular features, such as the models' eyes, mouth, and action targets. Previous studies reported that such viewing patterns vary significantly across individuals in humans, and also across closely-related primate species. However, the nature of these individual and species differences remains unclear, particularly among nonhuman primates. In large samples of human and nonhuman primates, we examined species differences and the effects of experience on patterns of gaze toward social movies. Experiment 1 examined the species differences across rhesus macaques, nonhuman apes (bonobos, chimpanzees, and orangutans), and humans while they viewed movies of various animals' species-typical behaviors. We found that each species had distinct viewing patterns of the models' faces, eyes, mouths, and action targets. Experiment 2 tested the effect of individuals' experience on chimpanzee and human viewing patterns. We presented movies depicting natural behaviors of chimpanzees to three groups of chimpanzees (individuals from a zoo, a sanctuary, and a research institute) differing in their early social and physical experiences. We also presented the same movies to human adults and children differing in their expertise with chimpanzees (experts vs. novices) or movie-viewing generally (adults vs. preschoolers). Individuals varied within each species in their patterns of gaze toward models' faces, eyes, mouths, and action targets depending on their unique individual experiences. We thus found that the viewing patterns for social stimuli are both individual- and species-specific in these closely-related primates. Such individual/species-specificities are likely related to both individual experience and species-typical temperament, suggesting that primate individuals acquire their unique attentional biases through both ontogeny and evolution. Such unique attentional biases may help them learn efficiently about their particular social environments.

  9. Eliciting mixed emotions: a meta-analysis comparing models, types, and measures.

    PubMed

    Berrios, Raul; Totterdell, Peter; Kellett, Stephen

    2015-01-01

    The idea that people can experience two oppositely valenced emotions has been controversial ever since early attempts to investigate the construct of mixed emotions. This meta-analysis examined the robustness with which mixed emotions have been elicited experimentally. A systematic literature search identified 63 experimental studies that instigated the experience of mixed emotions. Studies were distinguished according to the structure of the underlying affect model-dimensional or discrete-as well as according to the type of mixed emotions studied (e.g., happy-sad, fearful-happy, positive-negative). The meta-analysis using a random-effects model revealed a moderate to high effect size for the elicitation of mixed emotions (d IG+ = 0.77), which remained consistent regardless of the structure of the affect model, and across different types of mixed emotions. Several methodological and design moderators were tested. Studies using the minimum index (i.e., the minimum value between a pair of opposite valenced affects) resulted in smaller effect sizes, whereas subjective measures of mixed emotions increased the effect sizes. The presence of more women in the samples was also associated with larger effect sizes. The current study indicates that mixed emotions are a robust, measurable and non-artifactual experience. The results are discussed in terms of the implications for an affect system that has greater versatility and flexibility than previously thought.

  10. Density effects on electronic configurations in dense plasmas

    NASA Astrophysics Data System (ADS)

    Faussurier, Gérald; Blancard, Christophe

    2018-02-01

    We present a quantum mechanical model to describe the density effects on electronic configurations inside a plasma environment. Two different approaches are given by starting from a quantum average-atom model. Illustrations are shown for an aluminum plasma in local thermodynamic equilibrium at solid density and at a temperature of 100 eV and in the thermodynamic conditions of a recent experiment designed to characterize the effects of the ionization potential depression treatment. Our approach compares well with experiment and is consistent in that case with the approach of Stewart and Pyatt to describe the ionization potential depression rather than with the method of Ecker and Kröll.

  11. Does neighborhood size really cause the word length effect?

    PubMed

    Guitard, Dominic; Saint-Aubin, Jean; Tehan, Gerald; Tolan, Anne

    2018-02-01

    In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.'s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.

  12. Prevention of chemotherapy-induced alopecia in rodent models

    PubMed Central

    Jimenez, Joaquin J.; Roberts, Stephen M.; Mejia, Jessica; Mauro, Lucia M.; Munson, John W.; Elgart, George W.; Connelly, Elizabeth Alvarez; Chen, Qingbin; Zou, Jiangying; Goldenberg, Carlos

    2008-01-01

    Alopecia (hair loss) is experienced by thousands of cancer patients every year. Substantial-to-severe alopecia is induced by anthracyclines (e.g., adriamycin), taxanes (e.g., taxol), alkylating compounds (e.g., cyclophosphamide), and the topisomerase inhibitor etoposide, agents that are widely used in the treatment of leukemias and breast, lung, ovarian, and bladder cancers. Currently, no treatment appears to be generally effective in reliably preventing this secondary effect of chemotherapy. We observed in experiments using different rodent models that localized administration of heat or subcutaneous/intradermal injection of geldanamycin or 17-(allylamino)-17-demethoxygeldanamycin induced a stress protein response in hair follicles and effectively prevented alopecia from adriamycin, cyclophosphamide, taxol, and etoposide. Model tumor therapy experiments support the presumption that such localized hair-saving treatment does not negatively affect chemotherapy efficacy. PMID:18347939

  13. Pollutant dispersion in a large indoor space: Part 1 -- Scaled experiments using a water-filled model with occupants and furniture.

    PubMed

    Thatcher, T L; Wilson, D J; Wood, E E; Craig, M J; Sextro, R G

    2004-08-01

    Scale modeling is a useful tool for analyzing complex indoor spaces. Scale model experiments can reduce experimental costs, improve control of flow and temperature conditions, and provide a practical method for pretesting full-scale system modifications. However, changes in physical scale and working fluid (air or water) can complicate interpretation of the equivalent effects in the full-scale structure. This paper presents a detailed scaling analysis of a water tank experiment designed to model a large indoor space, and experimental results obtained with this model to assess the influence of furniture and people in the pollutant concentration field at breathing height. Theoretical calculations are derived for predicting the effects from losses of molecular diffusion, small scale eddies, turbulent kinetic energy, and turbulent mass diffusivity in a scale model, even without Reynolds number matching. Pollutant dispersion experiments were performed in a water-filled 30:1 scale model of a large room, using uranine dye injected continuously from a small point source. Pollutant concentrations were measured in a plane, using laser-induced fluorescence techniques, for three interior configurations: unobstructed, table-like obstructions, and table-like and figure-like obstructions. Concentrations within the measurement plane varied by more than an order of magnitude, even after the concentration field was fully developed. Objects in the model interior had a significant effect on both the concentration field and fluctuation intensity in the measurement plane. PRACTICAL IMPLICATION: This scale model study demonstrates both the utility of scale models for investigating dispersion in indoor environments and the significant impact of turbulence created by furnishings and people on pollutant transport from floor level sources. In a room with no furniture or occupants, the average concentration can vary by about a factor of 3 across the room. Adding furniture and occupants can increase this spatial variation by another factor of 3.

  14. Efficient Modeling and Active Learning Discovery of Biological Responses

    PubMed Central

    Naik, Armaghan W.; Kangas, Joshua D.; Langmead, Christopher J.; Murphy, Robert F.

    2013-01-01

    High throughput and high content screening involve determination of the effect of many compounds on a given target. As currently practiced, screening for each new target typically makes little use of information from screens of prior targets. Further, choices of compounds to advance to drug development are made without significant screening against off-target effects. The overall drug development process could be made more effective, as well as less expensive and time consuming, if potential effects of all compounds on all possible targets could be considered, yet the cost of such full experimentation would be prohibitive. In this paper, we describe a potential solution: probabilistic models that can be used to predict results for unmeasured combinations, and active learning algorithms for efficiently selecting which experiments to perform in order to build those models and determining when to stop. Using simulated and experimental data, we show that our approaches can produce powerful predictive models without exhaustive experimentation and can learn them much faster than by selecting experiments at random. PMID:24358322

  15. Scale effects in the response and failure of fiber reinforced composite laminates loaded in tension and in flexure

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Kellas, Sotiris; Morton, John

    1992-01-01

    The feasibility of using scale model testing for predicting the full-scale behavior of flat composite coupons loaded in tension and beam-columns loaded in flexure is examined. Classical laws of similitude are applied to fabricate and test replica model specimens to identify scaling effects in the load response, strength, and mode of failure. Experiments were performed on graphite-epoxy composite specimens having different laminate stacking sequences and a range of scaled sizes. From the experiments it was deduced that the elastic response of scaled composite specimens was independent of size. However, a significant scale effect in strength was observed. In addition, a transition in failure mode was observed among scaled specimens of certain laminate stacking sequences. A Weibull statistical model and a fracture mechanics based model were applied to predict the strength scale effect since standard failure criteria cannot account for the influence of absolute specimen size on strength.

  16. Elucidating the role of recovery experiences in the job demands-resources model.

    PubMed

    Moreno-Jiménez, Bernardo; Rodríguez-Muñoz, Alfredo; Sanz-Vergel, Ana Isabel; Garrosa, Eva

    2012-07-01

    Based on the Job Demands-Resources (JD-R) model, the current study examined the moderating role of recovery experiences (i.e., psychological detachment from work, relaxation, mastery experiences, and control over leisure time) on the relationship between one job demand (i.e., role conflict) and work- and health-related outcomes. Results from our sample of 990 employees from Spain showed that psychological detachment from work and relaxation buffered the negative impact of role conflict on some of the proposed outcomes. Contrary to our expectations, we did not find significant results for mastery and control regarding moderating effects. Overall, findings suggest a differential pattern of the recovery experiences in the health impairment process proposed by the JD-R model.

  17. Leading, but not trailing, primes influence temporal order perception: further evidence for an attentional account of perceptual latency priming.

    PubMed

    Scharlau, Ingrid

    2002-11-01

    Presenting a masked prime leading a target influences the perceived onset of the masking target (perceptual latency priming; Scharlau & Neumann, in press). This priming effect is explained by the asynchronous updating model (Neumann, 1982; Scharlau & Neumann, in press): The prime initiates attentional allocation toward its location, which renders a trailing target at the same place consciously available earlier. In three experiments, this perceptual latency priming by leading primes was examined jointly with the effects of trailing primes in order to compare the explanation of the asynchronous updating model with the onset-averaging and the P-center hypotheses. Experiment 1 showed that an attended, as well as an unattended, prime leads to perceptual latency priming. In addition, a large effect of trailing primes on the onset of a target was found. As Experiment 2 demonstrated, this effect is quite robust, although smaller than that of a leading prime. In Experiment 3, masked primes were used. Under these conditions, no influence of trailing primes could be found, whereas perceptual latency priming persisted. Thus, a nonattentional explanation for the effect of trailing primes seems likely.

  18. Robust optimal design of diffusion-weighted magnetic resonance experiments for skin microcirculation

    NASA Astrophysics Data System (ADS)

    Choi, J.; Raguin, L. G.

    2010-10-01

    Skin microcirculation plays an important role in several diseases including chronic venous insufficiency and diabetes. Magnetic resonance (MR) has the potential to provide quantitative information and a better penetration depth compared with other non-invasive methods such as laser Doppler flowmetry or optical coherence tomography. The continuous progress in hardware resulting in higher sensitivity must be coupled with advances in data acquisition schemes. In this article, we first introduce a physical model for quantifying skin microcirculation using diffusion-weighted MR (DWMR) based on an effective dispersion model for skin leading to a q-space model of the DWMR complex signal, and then design the corresponding robust optimal experiments. The resulting robust optimal DWMR protocols improve the worst-case quality of parameter estimates using nonlinear least squares optimization by exploiting available a priori knowledge of model parameters. Hence, our approach optimizes the gradient strengths and directions used in DWMR experiments to robustly minimize the size of the parameter estimation error with respect to model parameter uncertainty. Numerical evaluations are presented to demonstrate the effectiveness of our approach as compared to conventional DWMR protocols.

  19. FireStem2D – A Two-Dimensional Heat Transfer Model for Simulating Tree Stem Injury in Fires

    PubMed Central

    Chatziefstratiou, Efthalia K.; Bohrer, Gil; Bova, Anthony S.; Subramanian, Ravishankar; Frasson, Renato P. M.; Scherzer, Amy; Butler, Bret W.; Dickinson, Matthew B.

    2013-01-01

    FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by resolving stem moisture loss, temperatures through the stem, degree of bark charring, and necrotic depth around the stem. We present the results of numerical parameterization and model evaluation experiments for FireStem2D that simulate laboratory stem-heating experiments of 52 tree sections from 25 trees. We also conducted a set of virtual sensitivity analysis experiments to test the effects of unevenness of heating around the stem and with aboveground height using data from two studies: a low-intensity surface fire and a more intense crown fire. The model allows for improved understanding and prediction of the effects of wildland fire on injury and mortality of trees of different species and sizes. PMID:23894599

  20. Maximally Expressive Modeling of Operations Tasks

    NASA Technical Reports Server (NTRS)

    Jaap, John; Richardson, Lea; Davis, Elizabeth

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed, the information sought is at the cutting edge of scientific endeavor, and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a "maximally expressive" modeling schema.

  1. Three model space experiments on chemical reactions. [Gibbs adsorption, equilibrium shift and electrodeposition

    NASA Technical Reports Server (NTRS)

    Grodzka, P.; Facemire, B.

    1977-01-01

    Three investigations conducted aboard Skylab IV and Apollo-Soyuz involved phenomena that are of interest to the biochemistry community. The formaldehyde clock reaction and the equilibrium shift reaction experiments conducted aboard Apollo Soyuz demonstrate the effect of low-g foams or air/liquid dispersions on reaction rate and chemical equilibrium. The electrodeposition reaction experiment conducted aboard Skylab IV demonstrate the effect of a low-g environment on an electrochemical displacement reaction. The implications of the three space experiments for various applications are considered.

  2. Prediction of silicon oxynitride plasma etching using a generalized regression neural network

    NASA Astrophysics Data System (ADS)

    Kim, Byungwhan; Lee, Byung Teak

    2005-08-01

    A prediction model of silicon oxynitride (SiON) etching was constructed using a neural network. Model prediction performance was improved by means of genetic algorithm. The etching was conducted in a C2F6 inductively coupled plasma. A 24 full factorial experiment was employed to systematically characterize parameter effects on SiON etching. The process parameters include radio frequency source power, bias power, pressure, and C2F6 flow rate. To test the appropriateness of the trained model, additional 16 experiments were conducted. For comparison, four types of statistical regression models were built. Compared to the best regression model, the optimized neural network model demonstrated an improvement of about 52%. The optimized model was used to infer etch mechanisms as a function of parameters. The pressure effect was noticeably large only as relatively large ion bombardment was maintained in the process chamber. Ion-bombardment-activated polymer deposition played the most significant role in interpreting the complex effect of bias power or C2F6 flow rate. Moreover, [CF2] was expected to be the predominant precursor to polymer deposition.

  3. Multiscale modelling approaches for assessing cosmetic ingredients safety.

    PubMed

    Bois, Frédéric Y; Ochoa, Juan G Diaz; Gajewska, Monika; Kovarich, Simona; Mauch, Klaus; Paini, Alicia; Péry, Alexandre; Benito, Jose Vicente Sala; Teng, Sophie; Worth, Andrew

    2017-12-01

    The European Union's ban on animal testing for cosmetic ingredients and products has generated a strong momentum for the development of in silico and in vitro alternative methods. One of the focus of the COSMOS project was ab initio prediction of kinetics and toxic effects through multiscale pharmacokinetic modeling and in vitro data integration. In our experience, mathematical or computer modeling and in vitro experiments are complementary. We present here a summary of the main models and results obtained within the framework of the project on these topics. A first section presents our work at the organelle and cellular level. We then go toward modeling cell levels effects (monitored continuously), multiscale physiologically based pharmacokinetic and effect models, and route to route extrapolation. We follow with a short presentation of the automated KNIME workflows developed for dissemination and easy use of the models. We end with a discussion of two challenges to the field: our limited ability to deal with massive data and complex computations. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Experimental and numerical modeling of shrub crown fire initiation

    Treesearch

    Watcharapong Tachajapong; Jesse Lozano; Shakar Mahalingam; Xiangyang Zhou; David Weise

    2009-01-01

    The transition of fire from dry surface fuels to wet shrub crown fuels was studied using laboratory experiments and a simple physical model to gain a better understanding of the transition process. In the experiments, we investigated the effects of varying vertical distances between surface and crown fuels (crown base height), and of the wind speed on crown fire...

  5. Effects of Response Task and Accessory Stimuli on Redundancy Gain: Tests of the Hemispheric Coactivation Model

    ERIC Educational Resources Information Center

    Miller, Jeff; Van Nes, Fenna

    2007-01-01

    Two experiments tested predictions of the hemispheric coactivation model for redundancy gain (J. O. Miller, 2004). Simple reaction time was measured in divided attention tasks with visual stimuli presented to the left or right of fixation or redundantly to both sides. Experiment 1 tested the prediction that redundancy gain--the decrease in…

  6. Cognitive Architecture with Evolutionary Dynamics Solves Insight Problem.

    PubMed

    Fedor, Anna; Zachar, István; Szilágyi, András; Öllinger, Michael; de Vladar, Harold P; Szathmáry, Eörs

    2017-01-01

    In this paper, we show that a neurally implemented a cognitive architecture with evolutionary dynamics can solve the four-tree problem. Our model, called Darwinian Neurodynamics, assumes that the unconscious mechanism of problem solving during insight tasks is a Darwinian process. It is based on the evolution of patterns that represent candidate solutions to a problem, and are stored and reproduced by a population of attractor networks. In our first experiment, we used human data as a benchmark and showed that the model behaves comparably to humans: it shows an improvement in performance if it is pretrained and primed appropriately, just like human participants in Kershaw et al. (2013)'s experiment. In the second experiment, we further investigated the effects of pretraining and priming in a two-by-two design and found a beginner's luck type of effect: solution rate was highest in the condition that was primed, but not pretrained with patterns relevant for the task. In the third experiment, we showed that deficits in computational capacity and learning abilities decreased the performance of the model, as expected. We conclude that Darwinian Neurodynamics is a promising model of human problem solving that deserves further investigation.

  7. Cognitive Architecture with Evolutionary Dynamics Solves Insight Problem

    PubMed Central

    Fedor, Anna; Zachar, István; Szilágyi, András; Öllinger, Michael; de Vladar, Harold P.; Szathmáry, Eörs

    2017-01-01

    In this paper, we show that a neurally implemented a cognitive architecture with evolutionary dynamics can solve the four-tree problem. Our model, called Darwinian Neurodynamics, assumes that the unconscious mechanism of problem solving during insight tasks is a Darwinian process. It is based on the evolution of patterns that represent candidate solutions to a problem, and are stored and reproduced by a population of attractor networks. In our first experiment, we used human data as a benchmark and showed that the model behaves comparably to humans: it shows an improvement in performance if it is pretrained and primed appropriately, just like human participants in Kershaw et al. (2013)'s experiment. In the second experiment, we further investigated the effects of pretraining and priming in a two-by-two design and found a beginner's luck type of effect: solution rate was highest in the condition that was primed, but not pretrained with patterns relevant for the task. In the third experiment, we showed that deficits in computational capacity and learning abilities decreased the performance of the model, as expected. We conclude that Darwinian Neurodynamics is a promising model of human problem solving that deserves further investigation. PMID:28405191

  8. Comparison of Three Model Concepts for Streaming Potential in Unsaturated Porous Media

    NASA Astrophysics Data System (ADS)

    Huisman, J. A.; Satenahalli, P.; Zimmermann, E.; Vereecken, H.

    2017-12-01

    Streaming potential is the electric potential generated by fluid flow in a charged porous medium. Although streaming potential in saturated conditions is well understood, there still is considerable debate about the adequate modelling of streaming potential signals in unsaturated soil because different concepts are available to estimate the effective excess charge in unsaturated conditions. In particular, some studies have relied on the volumetric excess charge, whereas others proposed to use the flux-averaged excess charge derived from the water retention or relative permeability function. The aim of this study is to compare measured and modelled streaming potential signals for two different flow experiments with sand. The first experiment is a primary gravity drainage of a long column equipped with non-polarizing electrodes and tensiometers, as presented in several previous studies. Expected differences between the three concepts for the effective excess charge are only moderate for this set-up. The second experiment is a primary drainage of a short soil column equipped with non-polarizing electrodes and tensiometers using applied pressure, where differences between the three concepts are expected to be larger. A comparison of the experimental results with a coupled model of streaming potential for 1D flow problems will provide insights in the ability of the three model concepts for effective excess charge to describe observed streaming potentials.

  9. Benzodiazepines and antipsychotic medications for treatment of acute cocaine toxicity in animal models--a systematic review and meta-analysis.

    PubMed

    Heard, Kennon; Cleveland, Nathan R; Krier, Shay

    2011-11-01

    There are no controlled human studies to determine the efficacy of benzodiazepines or antipsychotic medications for prevention or treatment of acute cocaine toxicity. The only available controlled data are from animal models and these studies have reported inconsistent benefits. The objective of this study was to quantify the reported efficacy of benzodiazepines and antipsychotic medication for the prevention of mortality due to cocaine poisoning. We conducted a systematic review to identify English language articles describing experiments that compared a benzodiazepine or antipsychotic medication to placebo for the prevention of acute cocaine toxicity in an animal model. We then used these articles in a meta-analysis with a random-effects model to quantify the absolute risk reduction observed in these experiments. We found 10 articles evaluating antipsychotic medications and 15 articles evaluating benzodiazepines. Antipsychotic medications reduced the risk of death by 27% (95% CI, 15.2%-38.7%) compared to placebo and benzodiazepines reduced the risk of death by 52% (42.8%-60.7%) compared to placebo. Both treatments showed evidence of a dose-response effect, and no experiment found a statistically significant increase in risk of death. We conclude that both benzodiazepines and antipsychotic medications are effective for the prevention of lethality from cocaine toxicity in animal models.

  10. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling.

    PubMed

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-10-20

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

  11. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    PubMed Central

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-01-01

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics. PMID:26482650

  12. Experiments and Simulations of Fully Hydro-Mechanically Coupled Response of Rough Fractures Exposed to High-Pressure Fluid Injection

    NASA Astrophysics Data System (ADS)

    Vogler, D.; Settgast, R. R.; Annavarapu, C.; Madonna, C.; Bayer, P.; Amann, F.

    2018-02-01

    In this work, we present the application of a fully coupled hydro-mechanical method to investigate the effect of fracture heterogeneity on fluid flow through fractures at the laboratory scale. Experimental and numerical studies of fracture closure behavior in the presence of heterogeneous mechanical and hydraulic properties are presented. We compare the results of two sets of laboratory experiments on granodiorite specimens against numerical simulations in order to investigate the mechanical fracture closure and the hydro-mechanical effects, respectively. The model captures fracture closure behavior and predicts a nonlinear increase in fluid injection pressure with loading. Results from this study indicate that the heterogeneous aperture distributions measured for experiment specimens can be used as model input for a local cubic law model in a heterogeneous fracture to capture fracture closure behavior and corresponding fluid pressure response.

  13. Reactive flow modeling of initial density effect on divergence JB-9014 detonation driving

    NASA Astrophysics Data System (ADS)

    Yu, Xin; Huang, Kuibang; Zheng, Miao

    2016-06-01

    A serious of experiments were designed and the results were represented in this paper, in which 2mm thickness cooper shells were impacted by explosives named JB-9014 with different densities, and the surface velocities of the OFHC shells were measured. The comparison of experimental data shows the free surface velocity of the OFHC shell increase with the IHE density. Numerical modeling, which occupied phenomenological reactive flow rate model using the two-dimensional Lagrange hydrodynamic code, were carried out to simulate the above experiments, and empirical adjustments on detonation velocity and pressure and Pier Tang's adjustments on EOS of detonation products were both introduced in our numerical simulation work. The computational results agree well with that of experiments, and the numerical results with original parameters of products and the adjusted ones of JB-9014 could describe the density effect distinctly.

  14. Modeling criterion shifts and target checking in prospective memory monitoring.

    PubMed

    Horn, Sebastian S; Bayen, Ute J

    2015-01-01

    Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the reasons for this cost effect. This study uses diffusion model analysis to decompose monitoring processes in the PM paradigm. Across 4 experiments, performing a PM task increased latencies in an ongoing lexical decision task. A large portion of this effect was explained by consistent increases in boundary separation; additional increases in nondecision time emerged in a nonfocal PM task and explained variance in PM performance (Experiment 1), likely reflecting a target-checking strategy before and after the ongoing decision (Experiment 2). However, we found that possible target-checking strategies may depend on task characteristics. That is, instructional emphasis on the importance of ongoing decisions (Experiment 3) or the use of focal targets (Experiment 4) eliminated the contribution of nondecision time to the cost of PM, but left participants in a mode of increased cautiousness. The modeling thus sheds new light on the cost effect seen in many PM studies and suggests that people approach ongoing activities more cautiously when they need to remember an intended action. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  15. A novel approach for pilot error detection using Dynamic Bayesian Networks.

    PubMed

    Saada, Mohamad; Meng, Qinggang; Huang, Tingwen

    2014-06-01

    In the last decade Dynamic Bayesian Networks (DBNs) have become one type of the most attractive probabilistic modelling framework extensions of Bayesian Networks (BNs) for working under uncertainties from a temporal perspective. Despite this popularity not many researchers have attempted to study the use of these networks in anomaly detection or the implications of data anomalies on the outcome of such models. An abnormal change in the modelled environment's data at a given time, will cause a trailing chain effect on data of all related environment variables in current and consecutive time slices. Albeit this effect fades with time, it still can have an ill effect on the outcome of such models. In this paper we propose an algorithm for pilot error detection, using DBNs as the modelling framework for learning and detecting anomalous data. We base our experiments on the actions of an aircraft pilot, and a flight simulator is created for running the experiments. The proposed anomaly detection algorithm has achieved good results in detecting pilot errors and effects on the whole system.

  16. Using Voice Recognition Equipment to Run the Warfare Environmental Simulator (WES),

    DTIC Science & Technology

    1981-03-01

    simulations and models are often used. War games are a type of simulation frequently used by the military to evaluate C3 effectiveness. Through the use of a...to 162 words or short phrases (Appendix B). B. EQUIPMENT USED 1. Hardware Description [13] For the experiment a Threshold Model T600 discrete... Model T600 terminal used in this experiment con- sists of an analog speech preprocessor, microcomputer, CRT/keyboard unit, magnetic tape cartridge unit

  17. Category-length and category-strength effects using images of scenes.

    PubMed

    Baumann, Oliver; Vromen, Joyce M G; Boddy, Adam C; Crawshaw, Eloise; Humphreys, Michael S

    2018-06-21

    Global matching models have provided an important theoretical framework for recognition memory. Key predictions of this class of models are that (1) increasing the number of occurrences in a study list of some items affects the performance on other items (list-strength effect) and that (2) adding new items results in a deterioration of performance on the other items (list-length effect). Experimental confirmation of these predictions has been difficult, and the results have been inconsistent. A review of the existing literature, however, suggests that robust length and strength effects do occur when sufficiently similar hard-to-label items are used. In an effort to investigate this further, we had participants study lists containing one or more members of visual scene categories (bathrooms, beaches, etc.). Experiments 1 and 2 replicated and extended previous findings showing that the study of additional category members decreased accuracy, providing confirmation of the category-length effect. Experiment 3 showed that repeating some category members decreased the accuracy of nonrepeated members, providing evidence for a category-strength effect. Experiment 4 eliminated a potential challenge to these results. Taken together, these findings provide robust support for global matching models of recognition memory. The overall list lengths, the category sizes, and the number of repetitions used demonstrated that scene categories are well-suited to testing the fundamental assumptions of global matching models. These include (A) interference from memories for similar items and contexts, (B) nondestructive interference, and (C) that conjunctive information is made available through a matching operation.

  18. Effects of Couple Interactions and Relationship Quality on Plasma Oxytocin and Cardiovascular Reactivity: Empirical Findings and Methodological Considerations

    PubMed Central

    Smith, Timothy W.; Uchino, Bert N.; MacKenzie, Justin; Hicks, Angela; Campo, Rebecca A.; Reblin, Maija; Grewen, Karen; Amico, Janet A.; Light, Kathleen C.

    2016-01-01

    Cardiovascular reactivity is a potential mechanism underlying associations of close relationship quality with cardiovascular disease. Two models describe oxytocin as another mechanism. The “calm and connect” model posits an association between positive relationship experiences and oxytocin levels and responses, whereas the “tend and befriend” model emphasizes the effects of negative relationship experiences in evoking oxytocin release. In this study of 180 younger couples, relationship quality had a small, marginally significant inverse association with plasma oxytocin levels, and neither positive nor negative couple interactions evoked change in plasma oxytocin. Negative couple interactions evoked significant cardiovascular reactivity, especially among women. Hence, in the largest study of these issues to date, there was little support for key tenets of the “calm and connect” model, and only very modest support for the ”tend and befriend” model. However, findings were consistent with the view that CVR contributes to the effects of relationship difficulties on health. PMID:22543270

  19. Disaster Reintegration Model: A Qualitative Analysis on Developing Korean Disaster Mental Health Support Model

    PubMed Central

    O’Donnell, Meaghan

    2018-01-01

    This study sought to describe the mental health problems experienced by Korean disaster survivors, using a qualitative research method to provide empirical resources for effective disaster mental health support in Korea. Participants were 16 adults or elderly adults who experienced one or more disasters at least 12 months ago recruited via theoretical sampling. Participants underwent in-depth individual interviews on their disaster experiences, which were recorded and transcribed for qualitative analysis, which followed Strauss and Corbin’s (1998) Grounded theory. After open coding, participants’ experiences were categorized into 130 codes, 43 sub-categories and 17 categories. The categories were further analyzed in a paradigm model, conditional model and the Disaster Reintegration Model, which proposed potentially effective mental health recovery strategies for disaster survivors, health providers and administrators. To provide effective assistance for mental health recovery of disaster survivors, both personal and public resilience should be promoted while considering both cultural and spiritual elements. PMID:29463030

  20. An experiment to study the effects of space flight cells of mesenchymal origin in the new model 3D-graft in vitro

    NASA Astrophysics Data System (ADS)

    Volova, Larissa

    One of the major health problems of the astronauts are disorders of the musculoskeletal system, which determines the relevance of studies of the effect of space flight factors on osteoblastic and hondroblastic cells in vitro. An experiment to study the viability and proliferative activity of cells of mesenchymal origin on culture: chondroblasts and dermal fibroblasts was performed on SC "BION -M" No. 1 with scientific equipment " BIOKONT -B ." To study the effect of space flight conditions in vitro at the cellular level has developed a new model with 3D- graft as allogeneic demineralized spongiosa obtained on technology Lioplast ®. For space and simultaneous experiments in the laboratory of the Institute of Experimental Medicine and Biotechnology Samara State Medical University were obtained from the cell culture of hyaline cartilage and human skin, which have previously been grown, and then identified by morphological and immunohistochemical methods. In the experiment, they were seeded on the porous 3D- graft (controlled by means of scanning electron and confocal microscopy) and cultured in full growth medium. After completion of the flight of spacecraft "BION -M" No. 1 conducted studies of biological objects using a scanning electron microscope (JEOL JSM-6390A Analysis Station, Japan), confocal microscopy and LDH - test. According to the results of the experiment revealed that after a 30- day flight of the cells not only retained vitality, but also during the flight actively proliferate, and their number has increased by almost 8 times. In synchronous experiment, all the cells died by this date. The experimentally confirmed the adequacy of the proposed model 3D- graft in studying the effect of space flight on the morphological and functional characteristics of cells in vitro.

  1. "The empathy impulse: A multinomial model of intentional and unintentional empathy for pain": Correction.

    PubMed

    2018-04-01

    Reports an error in "The empathy impulse: A multinomial model of intentional and unintentional empathy for pain" by C. Daryl Cameron, Victoria L. Spring and Andrew R. Todd ( Emotion , 2017[Apr], Vol 17[3], 395-411). In this article, there was an error in the calculation of some of the effect sizes. The w effect size was manually computed incorrectly. The incorrect number of total observations was used, which affected the final effect size estimates. This computing error does not change any of the results or interpretations about model fit based on the G² statistic, or about significant differences across conditions in process parameters. Therefore, it does not change any of the hypothesis tests or conclusions. The w statistics for overall model fit should be .02 instead of .04 in Study 1, .01 instead of .02 in Study 2, .01 instead of .03 for the OIT in Study 3 (model fit for the PIT remains the same: .00), and .02 instead of .03 in Study 4. The corrected tables can be seen here: http://osf.io/qebku at the Open Science Framework site for the article. (The following abstract of the original article appeared in record 2017-01641-001.) Empathy for pain is often described as automatic. Here, we used implicit measurement and multinomial modeling to formally quantify unintentional empathy for pain: empathy that occurs despite intentions to the contrary. We developed the pain identification task (PIT), a sequential priming task wherein participants judge the painfulness of target experiences while trying to avoid the influence of prime experiences. Using multinomial modeling, we distinguished 3 component processes underlying PIT performance: empathy toward target stimuli (Intentional Empathy), empathy toward prime stimuli (Unintentional Empathy), and bias to judge target stimuli as painful (Response Bias). In Experiment 1, imposing a fast (vs. slow) response deadline uniquely reduced Intentional Empathy. In Experiment 2, inducing imagine-self (vs. imagine-other) perspective-taking uniquely increased Unintentional Empathy. In Experiment 3, Intentional and Unintentional Empathy were stronger toward targets with typical (vs. atypical) pain outcomes, suggesting that outcome information matters and that effects on the PIT are not reducible to affective priming. Typicality of pain outcomes more weakly affected task performance when target stimuli were merely categorized rather than judged for painfulness, suggesting that effects on the latter are not reducible to semantic priming. In Experiment 4, Unintentional Empathy was stronger for participants who engaged in costly donation to cancer charities, but this parameter was also high for those who donated to an objectively worse but socially more popular charity, suggesting that overly high empathy may facilitate maladaptive altruism. Theoretical and practical applications of our modeling approach for understanding variation in empathy are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  2. Ultracold Nonreactive Molecules in an Optical Lattice: Connecting Chemistry to Many-Body Physics.

    PubMed

    Doçaj, Andris; Wall, Michael L; Mukherjee, Rick; Hazzard, Kaden R A

    2016-04-01

    We derive effective lattice models for ultracold bosonic or fermionic nonreactive molecules (NRMs) in an optical lattice, analogous to the Hubbard model that describes ultracold atoms in a lattice. In stark contrast to the Hubbard model, which is commonly assumed to accurately describe NRMs, we find that the single on-site interaction parameter U is replaced by a multichannel interaction, whose properties we elucidate. Because this arises from complex short-range collisional physics, it requires no dipolar interactions and thus occurs even in the absence of an electric field or for homonuclear molecules. We find a crossover between coherent few-channel models and fully incoherent single-channel models as the lattice depth is increased. We show that the effective model parameters can be determined in lattice modulation experiments, which, consequently, measure molecular collision dynamics with a vastly sharper energy resolution than experiments in a free-space ultracold gas.

  3. Causes of variation among rice models in yield response to CO2 examined with Free-Air CO2 Enrichment and growth chamber experiments.

    PubMed

    Hasegawa, Toshihiro; Li, Tao; Yin, Xinyou; Zhu, Yan; Boote, Kenneth; Baker, Jeffrey; Bregaglio, Simone; Buis, Samuel; Confalonieri, Roberto; Fugice, Job; Fumoto, Tamon; Gaydon, Donald; Kumar, Soora Naresh; Lafarge, Tanguy; Marcaida Iii, Manuel; Masutomi, Yuji; Nakagawa, Hiroshi; Oriol, Philippe; Ruget, Françoise; Singh, Upendra; Tang, Liang; Tao, Fulu; Wakatsuki, Hitomi; Wallach, Daniel; Wang, Yulong; Wilson, Lloyd Ted; Yang, Lianxin; Yang, Yubin; Yoshida, Hiroe; Zhang, Zhao; Zhu, Jianguo

    2017-11-01

    The CO 2 fertilization effect is a major source of uncertainty in crop models for future yield forecasts, but coordinated efforts to determine the mechanisms of this uncertainty have been lacking. Here, we studied causes of uncertainty among 16 crop models in predicting rice yield in response to elevated [CO 2 ] (E-[CO 2 ]) by comparison to free-air CO 2 enrichment (FACE) and chamber experiments. The model ensemble reproduced the experimental results well. However, yield prediction in response to E-[CO 2 ] varied significantly among the rice models. The variation was not random: models that overestimated at one experiment simulated greater yield enhancements at the others. The variation was not associated with model structure or magnitude of photosynthetic response to E-[CO 2 ] but was significantly associated with the predictions of leaf area. This suggests that modelled secondary effects of E-[CO 2 ] on morphological development, primarily leaf area, are the sources of model uncertainty. Rice morphological development is conservative to carbon acquisition. Uncertainty will be reduced by incorporating this conservative nature of the morphological response to E-[CO 2 ] into the models. Nitrogen levels, particularly under limited situations, make the prediction more uncertain. Improving models to account for [CO 2 ] × N interactions is necessary to better evaluate management practices under climate change.

  4. Proposal for optimal placement platform of bikes using queueing networks.

    PubMed

    Mizuno, Shinya; Iwamoto, Shogo; Seki, Mutsumi; Yamaki, Naokazu

    2016-01-01

    In recent social experiments, rental motorbikes and rental bicycles have been arranged at nodes, and environments where users can ride these bikes have been improved. When people borrow bikes, they return them to nearby nodes. Some experiments have been conducted using the models of Hamachari of Yokohama, the Niigata Rental Cycle, and Bicing. However, from these experiments, the effectiveness of distributing bikes was unclear, and many models were discontinued midway. Thus, we need to consider whether these models are effectively designed to represent the distribution system. Therefore, we construct a model to arrange the nodes for distributing bikes using a queueing network. To adopt realistic values for our model, we use the Google Maps application program interface. Thus, we can easily obtain values of distance and transit time between nodes in various places in the world. Moreover, we apply the distribution of a population to a gravity model and we compute the effective transition probability for this queueing network. If the arrangement of the nodes and number of bikes at each node is known, we can precisely design the system. We illustrate our system using convenience stores as nodes and optimize the node configuration. As a result, we can optimize simultaneously the number of nodes, node places, and number of bikes for each node, and we can construct a base for a rental cycle business to use our system.

  5. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Florian Wellmann, J.; Thiele, Sam T.; Lindsay, Mark D.; Jessell, Mark W.

    2016-03-01

    We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilize the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.

  6. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Wellmann, J. F.; Thiele, S. T.; Lindsay, M. D.; Jessell, M. W.

    2015-11-01

    We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilise the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a~link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential-fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.

  7. Evaluation for the design of experience in virtual environments: modeling breakdown of interaction and illusion.

    PubMed

    Marsh, T; Wright, P; Smith, S

    2001-04-01

    New and emerging media technologies have the potential to induce a variety of experiences in users. In this paper, it is argued that the inducement of experience presupposes that users are absorbed in the illusion created by these media. Looking to another successful visual medium, film, this paper borrows from the techniques used in "shaping experience" to hold spectators' attention in the illusion of film, and identifies what breaks the illusion/experience for spectators. This paper focuses on one medium, virtual reality (VR), and advocates a transparent or "invisible style" of interaction. We argue that transparency keeps users in the "flow" of their activities and consequently enhances experience in users. Breakdown in activities breaks the experience and subsequently provides opportunities to identify and analyze potential causes of usability problems. Adopting activity theory, we devise a model of interaction with VR--through consciousness and activity--and introduce the concept of breakdown in illusion. From this, a model of effective interaction with VR is devised and the occurrence of breakdown in interaction and illusion is identified along a continuum of engagement. Evaluation guidelines for the design of experience are proposed and applied to usability problems detected in an empirical study of a head-mounted display (HMD) VR system. This study shows that the guidelines are effective in the evaluation of VR. Finally, we look at the potential experiences that may be induced in users and propose a way to evaluate user experience in virtual environments (VEs) and other new and emerging media.

  8. TRANSPORT, RADIATIVE, AND DYNAMICAL EFFECTS OF THE ANTARCTIC OZONE HOLE: A GFDL "SKYHI" MODEL EXPERIMENT

    EPA Science Inventory

    The GFDL 'SKYHI' general circulation model has been used to simulate the effect of the Antarctic "ozone hole" phenomenon on the radiative and dynamical environment of the lower stratosphere. oth the polar ozone destruction and photochemical restoration chemistries are calculated ...

  9. Multiple lesion track structure model

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1992-01-01

    A multilesion cell kinetic model is derived, and radiation kinetic coefficients are related to the Katz track structure model. The repair-related coefficients are determined from the delayed plating experiments of Yang et al. for the C3H10T1/2 cell system. The model agrees well with the x ray and heavy ion experiments of Yang et al. for the immediate plating, delaying plating, and fractionated exposure protocols employed by Yang. A study is made of the effects of target fragments in energetic proton exposures and of the repair-deficient target-fragment-induced lesions.

  10. Modeling of turbulent separated flows for aerodynamic applications

    NASA Technical Reports Server (NTRS)

    Marvin, J. G.

    1983-01-01

    Steady, high speed, compressible separated flows modeled through numerical simulations resulting from solutions of the mass-averaged Navier-Stokes equations are reviewed. Emphasis is placed on benchmark flows that represent simplified (but realistic) aerodynamic phenomena. These include impinging shock waves, compression corners, glancing shock waves, trailing edge regions, and supersonic high angle of attack flows. A critical assessment of modeling capabilities is provided by comparing the numerical simulations with experiment. The importance of combining experiment, numerical algorithm, grid, and turbulence model to effectively develop this potentially powerful simulation technique is stressed.

  11. Limits to the Positive Effect of Ocean Acidification on Macroalgal Primary Production, Interactions with Light and Temperature

    NASA Astrophysics Data System (ADS)

    Kubler, J.; Dudgeon, S. R.; Nisumaa, A. M.

    2016-02-01

    About one third of macroalgal species lack any carbon concentrating mechanism (CCM), which prevents carbon limitation under air equilibrium in other seaweed species. It is predicted that those species lacking CCM's will benefit from ongoing ocean acidification in terms of primary productivity and growth. The absolute sizes and pattern of those benefits are not known. Here, we compare the results of a model based on composite data from the literature, with a growth experiment using Plocamium cartilagineum, a broadly distributed rhodophyte species lacking a carbon concentrating mechanism and hypothesized to be carbon limited under current conditions. We grew P. cartilagineum, at 15 and 20°C in seawater aerated with a total of 53 different pCO2s (from 344 to 1053µatm), in 8 multiweek trials over 12 months. We measured growth and photosynthetic rates. A linear mixed model analysis was used to partition the effect sizes of drivers of variation in the experiment. The growth rates and maximum photosynthetic rates responded nonlinearly to OA, increasing with elevated pCO2 from recent atmospheric level to up 450µatm and decreasing at higher pCO2. Light harvesting efficiency was unaffected by pCO2 and inversely related to temperature. We were able to compare the results of the growth experiment directly to the model based on the additive effects of temperature and pCO2 on photosynthetic rates, finding concordance of the pattern of response. The size of the effect of pCO2 on growth rate in the experiment was greater than the effect predicted by the model for net primary productivity. These results predict that the benefit of OA for macroalgal growth may disappear as ocean acidification continues through this century.

  12. On the Modeling of the Residual Effects of the Clock Behavior and the Atmosphere Effects in the Analysis of VLBI Data

    NASA Astrophysics Data System (ADS)

    Bo, Zhang; Li, Jin-Ling; Wang, Guan-Gli

    2002-01-01

    We checked the dependence of the estimation of parameters on the choice of piecewise interval in the continuous piecewise linear modeling of the residual clock and atmosphere effects by single analysis of 27 VLBI experiments involving Shanghai station (Seshan 25m). The following are tentatively shown: (1) Different choices of the piecewise interval lead to differences in the estimation of station coordinates and in the weighted root mean squares ( wrms ) of the delay residuals, which can be of the order of centimeters or dozens of picoseconds respectively. So the choice of piecewise interval should not be arbitrary . (2) The piecewise interval should not be too long, otherwise the short - term variations in the residual clock and atmospheric effects can not be properly modeled. While in order to maintain enough degrees of freedom in parameter estimation, the interval can not be too short, otherwise the normal equation may become near or solely singular and the noises can not be constrained as well. Therefore the choice of the interval should be within some reasonable range. (3) Since the conditions of clock and atmosphere are different from experiment to experiment and from station to station, the reasonable range of the piecewise interval should be tested and chosen separately for each experiment as well as for each station by real data analysis. This is really arduous work in routine data analysis. (4) Generally speaking, with the default interval for clock as 60min, the reasonable range of piecewise interval for residual atmospheric effect modeling is between 10min to 40min, while with the default interval for atmosphere as 20min, that for residual clock behavior is between 20min to 100min.

  13. Potential sources of variability in mesocosm experiments on the response of phytoplankton to ocean acidification

    NASA Astrophysics Data System (ADS)

    Moreno de Castro, Maria; Schartau, Markus; Wirtz, Kai

    2017-04-01

    Mesocosm experiments on phytoplankton dynamics under high CO2 concentrations mimic the response of marine primary producers to future ocean acidification. However, potential acidification effects can be hindered by the high standard deviation typically found in the replicates of the same CO2 treatment level. In experiments with multiple unresolved factors and a sub-optimal number of replicates, post-processing statistical inference tools might fail to detect an effect that is present. We propose that in such cases, data-based model analyses might be suitable tools to unearth potential responses to the treatment and identify the uncertainties that could produce the observed variability. As test cases, we used data from two independent mesocosm experiments. Both experiments showed high standard deviations and, according to statistical inference tools, biomass appeared insensitive to changing CO2 conditions. Conversely, our simulations showed earlier and more intense phytoplankton blooms in modeled replicates at high CO2 concentrations and suggested that uncertainties in average cell size, phytoplankton biomass losses, and initial nutrient concentration potentially outweigh acidification effects by triggering strong variability during the bloom phase. We also estimated the thresholds below which uncertainties do not escalate to high variability. This information might help in designing future mesocosm experiments and interpreting controversial results on the effect of acidification or other pressures on ecosystem functions.

  14. The Effect of STEM Learning through the Project of Designing Boat Model toward Student STEM Literacy

    NASA Astrophysics Data System (ADS)

    Tati, T.; Firman, H.; Riandi, R.

    2017-09-01

    STEM Learning focusses on development of STEM-literate society, the research about implementation of STEM learning to develope students’ STEM literacy is still limited. This study is aimed to examine the effect of implementation STEM learning through the project of designing boat model on students STEM literacy in energy topic. The method of this study was a quasi-experiment with non-randomized pretest-posttest control group design. There were two classes involved, the experiment class used Project Based Learning with STEM approach and control class used Project-Based Learning without STEM approach. A STEM Literacy test instrument was developed to measure students STEM literacy which consists of science literacy, mathematics literacy, and technology-engineering literacy. The analysis showed that there were significant differences on improvement science literacy, mathematics technology-engineering between experiment class and control class with effect size more than 0.8 (large effect). The difference of improvement of STEM literacy between experiment class and control class is caused by the existence of design engineering activity which required students to apply the knowledge from every field of STEM. The challenge that was faced in STEM learning through design engineering activity was how to give the students practice to integrate STEM field in solving the problems. In additional, most of the students gave positive response toward implementation of STEM learning through design boat model project.

  15. Experimental droughts: Are precipitation variability and methodological trends hindering our understanding of ecological sensitivities to drought?

    NASA Astrophysics Data System (ADS)

    Hoover, D. L.; Wilcox, K.; Young, K. E.

    2017-12-01

    Droughts are projected to increase in frequency and intensity with climate change, which may have dramatic and prolonged effects on ecosystem structure and function. There are currently hundreds of published, ongoing, and new drought experiments worldwide aimed to assess ecosystem sensitivities to drought and identify the mechanisms governing ecological resistance and resilience. However, to date, the results from these experiments have varied widely, and thus patterns of drought sensitivities have been difficult to discern. This lack of consensus at the field scale, limits the abilities of experiments to help improve land surface models, which often fail to realistically simulate ecological responses to extreme events. This is unfortunate because models offer an alternative, yet complementary approach to increase the spatial and temporal assessment of ecological sensitivities to drought that are not possible in the field due to logistical and financial constraints. Here we examined 89 published drought experiments, along with their associated historical precipitation records to (1) identify where and how drought experiments have been imposed, (2) determine the extremity of drought treatments in the context of historical climate, and (3) assess the influence of precipitation variability on drought experiments. We found an overall bias in drought experiments towards short-term, extreme experiments in water-limited ecosystems. When placed in the context of local historical precipitation, most experimental droughts were extreme, with 61% below the 5th, and 43% below the 1st percentile. Furthermore, we found that interannual precipitation variability had a large and potentially underappreciated effect on drought experiments due to the co-varying nature of control and drought treatments. Thus detecting ecological effects in experimental droughts is strongly influenced by the interaction between drought treatment magnitude, precipitation variability, and key physiological thresholds. The results from this study have important implication for the design and interpretation of drought experiments as well as integrating field results with land surface models.

  16. Analysis of Residual Acceleration Effects on Transport and Segregation During Directional Solidification of Tin-Bismuth in the MEPHISTO Furnace Facility

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.; Lizee, Arnaud

    1996-01-01

    The object of this work, started in March of 1995, is to approach the problem of determining the transport conditions (and effects of residual acceleration) during the plane-front directional solidification of a tin-bismuth alloy under low gravity conditions. The work involves using a combination of 2- and 3-D numerical models, scaling analyses, 1-D models and the results of ground-based and low-gravity experiments. The experiments conducted in the MEPHISTO furnace facility during the USMP-3 spaceflight which took place earlier this year (22 Feb. - 6 Mar. 1996). This experiment represents an unprecedented opportunity to make a quantitative correlation between residual accelerations and the response of an actual experimental solidification system

  17. Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

    NASA Astrophysics Data System (ADS)

    Antonopoulou, Evangelia; Rohmann-Shaw, Connor F.; Sykes, Thomas C.; Cayre, Olivier J.; Hunter, Timothy N.; Jimack, Peter K.

    2018-03-01

    Understanding the sedimentation behaviour of colloidal suspensions is crucial in determining their stability. Since sedimentation rates are often very slow, centrifugation is used to expedite sedimentation experiments. The effect of centrifugal acceleration on sedimentation behaviour is not fully understood. Furthermore, in sedimentation models, interparticle interactions are usually omitted by using the hard-sphere assumption. This work proposes a one-dimensional model for sedimentation using an effective maximum volume fraction, with an extension for sedimentation under centrifugal force. A numerical implementation of the model using an adaptive finite difference solver is described. Experiments with silica suspensions are carried out using an analytical centrifuge. The model is shown to be a good fit with experimental data for 480 nm spherical silica, with the effects of centrifugation at 705 rpm studied. A conversion of data to Earth gravity conditions is proposed, which is shown to recover Earth gravity sedimentation rates well. This work suggests that the effective maximum volume fraction accurately captures interparticle interactions and provides insights into the effect of centrifugation on sedimentation.

  18. Teaching for Transformative Experience in Science: An Investigation of the Effectiveness of Two Instructional Elements.

    ERIC Educational Resources Information Center

    Pugh, Kevin J.

    2002-01-01

    Examined the effectiveness of two teaching elements (the artistic crafting of content and the modeling and scaffolding of perception and value) at fostering transformative experiences among students in a high school zoology class. Student outcomes were compared to the outcomes of students in a class taught with a case-based method. Significantly…

  19. The Effect of Blog Use on Self-Regulatory Learning of Prospective German Language Teachers

    ERIC Educational Resources Information Center

    Seyhan Yucel, Mukadder

    2013-01-01

    The purpose of the study was to examine the effect of blog use on self-regulatory learning of prospective German language teachers. The study is semi-experimental. Pretest-posttest, experiment control model was used. Blog activities were conducted as extensive beyond classroom activities only for the experiment group. As the data collection tool…

  20. Grounded Learning Experience: Helping Students Learn Physics through Visuo-Haptic Priming and Instruction

    NASA Astrophysics Data System (ADS)

    Huang, Shih-Chieh Douglas

    In this dissertation, I investigate the effects of a grounded learning experience on college students' mental models of physics systems. The grounded learning experience consisted of a priming stage and an instruction stage, and within each stage, one of two different types of visuo-haptic representation was applied: visuo-gestural simulation (visual modality and gestures) and visuo-haptic simulation (visual modality, gestures, and somatosensory information). A pilot study involving N = 23 college students examined how using different types of visuo-haptic representation in instruction affected people's mental model construction for physics systems. Participants' abilities to construct mental models were operationalized through their pretest-to-posttest gain scores for a basic physics system and their performance on a transfer task involving an advanced physics system. Findings from this pilot study revealed that, while both simulations significantly improved participants' mental modal construction for physics systems, visuo-haptic simulation was significantly better than visuo-gestural simulation. In addition, clinical interviews suggested that participants' mental model construction for physics systems benefited from receiving visuo-haptic simulation in a tutorial prior to the instruction stage. A dissertation study involving N = 96 college students examined how types of visuo-haptic representation in different applications support participants' mental model construction for physics systems. Participant's abilities to construct mental models were again operationalized through their pretest-to-posttest gain scores for a basic physics system and their performance on a transfer task involving an advanced physics system. Participants' physics misconceptions were also measured before and after the grounded learning experience. Findings from this dissertation study not only revealed that visuo-haptic simulation was significantly more effective in promoting mental model construction and remedying participants' physics misconceptions than visuo-gestural simulation, they also revealed that visuo-haptic simulation was more effective during the priming stage than during the instruction stage. Interestingly, the effects of visuo-haptic simulation in priming and visuo-haptic simulation in instruction on participants' pretest-to-posttest gain scores for a basic physics system appeared additive. These results suggested that visuo-haptic simulation is effective in physics learning, especially when it is used during the priming stage.

  1. The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

    NASA Astrophysics Data System (ADS)

    Wardaya, P. D.; Noh, K. A. B. M.; Yusoff, W. I. B. W.; Ridha, S.; Nurhandoko, B. E. B.

    2014-09-01

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave velocity of rock.

  2. Syllables and bigrams: orthographic redundancy and syllabic units affect visual word recognition at different processing levels.

    PubMed

    Conrad, Markus; Carreiras, Manuel; Tamm, Sascha; Jacobs, Arthur M

    2009-04-01

    Over the last decade, there has been increasing evidence for syllabic processing during visual word recognition. If syllabic effects prove to be independent from orthographic redundancy, this would seriously challenge the ability of current computational models to account for the processing of polysyllabic words. Three experiments are presented to disentangle effects of the frequency of syllabic units and orthographic segments in lexical decision. In Experiment 1 the authors obtained an inhibitory syllable frequency effect that was unaffected by the presence or absence of a bigram trough at the syllable boundary. In Experiments 2 and 3 an inhibitory effect of initial syllable frequency but a facilitative effect of initial bigram frequency emerged when manipulating 1 of the 2 measures and controlling for the other in Spanish words starting with consonant-vowel syllables. The authors conclude that effects of syllable frequency and letter-cluster frequency are independent and arise at different processing levels of visual word recognition. Results are discussed within the framework of an interactive activation model of visual word recognition. (c) 2009 APA, all rights reserved.

  3. Watching Faults Grow in Sand

    NASA Astrophysics Data System (ADS)

    Cooke, M. L.

    2015-12-01

    Accretionary sandbox experiments provide a rich environment for investigating the processes of fault development. These experiments engage students because 1) they enable direct observation of fault growth, which is impossible in the crust (type 1 physical model), 2) they are not only representational but can also be manipulated (type 2 physical model), 3) they can be used to test hypotheses (type 3 physical model) and 4) they resemble experiments performed by structural geology researchers around the world. The structural geology courses at UMass Amherst utilize a series of accretionary sandboxes experiments where students first watch a video of an experiment and then perform a group experiment. The experiments motivate discussions of what conditions they would change and what outcomes they would expect from these changes; hypothesis development. These discussions inevitably lead to calculations of the scaling relationships between model and crustal fault growth and provide insight into the crustal processes represented within the dry sand. Sketching of the experiments has been shown to be a very effective assessment method as the students reveal which features they are analyzing. Another approach used at UMass is to set up a forensic experiment. The experiment is set up with spatially varying basal friction before the meeting and students must figure out what the basal conditions are through the experiment. This experiment leads to discussions of equilibrium and force balance within the accretionary wedge. Displacement fields can be captured throughout the experiment using inexpensive digital image correlation techniques to foster quantitative analysis of the experiments.

  4. Isolating Curvature Effects in Computing Wall-Bounded Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher L.; Gatski, Thomas B.

    2001-01-01

    The flow over the zero-pressure-gradient So-Mellor convex curved wall is simulated using the Navier-Stokes equations. An inviscid effective outer wall shape, undocumented in the experiment, is obtained by using an adjoint optimization method with the desired pressure distribution on the inner wall as the cost function. Using this wall shape with a Navier-Stokes method, the abilities of various turbulence models to simulate the effects of curvature without the complicating factor of streamwise pressure gradient can be evaluated. The one-equation Spalart-Allmaras turbulence model overpredicts eddy viscosity, and its boundary layer profiles are too full. A curvature-corrected version of this model improves results, which are sensitive to the choice of a particular constant. An explicit algebraic stress model does a reasonable job predicting this flow field. However, results can be slightly improved by modifying the assumption on anisotropy equilibrium in the model's derivation. The resulting curvature-corrected explicit algebraic stress model possesses no heuristic functions or additional constants. It lowers slightly the computed skin friction coefficient and the turbulent stress levels for this case (in better agreement with experiment), but the effect on computed velocity profiles is very small.

  5. Numerical and Experimental Investigation of the Effects of Acceleration Disturbances on Microgravity Experiments

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan

    2000-01-01

    Normal vibrational modes on large spacecraft are excited by crew activity, operating machinery, and other mechanical disturbances. Periodic engine burns for maintaining vehicle attitude and random impulse type disturbances also contribute to the acceleration environment of a Spacecraft. Accelerations from these vibrations (often referred to as g-jitter) are several orders of magnitude larger than the residual accelerations from atmospheric drag and gravity gradient effects. Naturally, the effects of such accelerations have been a concern to prospective experimenters wishing to take advantage of the microgravity environment offered by spacecraft operating in low Earth orbit and the topic has been studied extensively, both numerically and analytically. However, these studies have not produced a general theory that predicts the effects of multi-spectral periodic accelerations on a general class of experiments nor have they produced scaling laws that a prospective experimenter could use to assess how his/her experiment might be affected by this acceleration environment. Furthermore, there are no actual flight experimental data that correlates heat or mass transport with measurements of the periodic acceleration environment. The present investigation approaches this problem with carefully conducted terrestrial experiments and rigorous numerical modeling thereby providing comparative theoretical and experimental data. The modeling, it is hoped will provide a predictive tool that can be used for assessing experiment response to Spacecraft vibrations.

  6. Can training improve the quality of inferences made by raters in competency modeling? A quasi-experiment.

    PubMed

    Lievens, Filip; Sanchez, Juan I

    2007-05-01

    A quasi-experiment was conducted to investigate the effects of frame-of-reference training on the quality of competency modeling ratings made by consultants. Human resources consultants from a large consulting firm were randomly assigned to either a training or a control condition. The discriminant validity, interrater reliability, and accuracy of the competency ratings were significantly higher in the training group than in the control group. Further, the discriminant validity and interrater reliability of competency inferences were highest among an additional group of trained consultants who also had competency modeling experience. Together, these results suggest that procedural interventions such as rater training can significantly enhance the quality of competency modeling. 2007 APA, all rights reserved

  7. Weak interspecific interactions in a sagebrush steppe? Conflicting evidence from observations and experiments.

    PubMed

    Adler, Peter B; Kleinhesselink, Andrew; Giles, Hooker; Taylor, J Bret; Teller, Brittany; Ellner, Stephen P

    2018-04-28

    Stable coexistence requires intraspecific limitations to be stronger than interspecific limitations. The greater the difference between intra- and interspecific limitations, the more stable the coexistence, and the weaker the competitive release any species should experience following removal of competitors. We conducted a removal experiment to test whether a previously estimated model, showing surprisingly weak interspecific competition for four dominant species in a sagebrush steppe, accurately predicts competitive release. Our treatments were 1) removal of all perennial grasses and 2) removal of the dominant shrub, Artemisia tripartita. We regressed survival, growth and recruitment on the locations, sizes, and species identities of neighboring plants, along with an indicator variable for removal treatment. If our "baseline" regression model, which accounts for local plant-plant interactions, accurately explains the observed responses to removals, then the removal coefficient should be non-significant. For survival, the removal coefficients were never significantly different from zero, and only A. tripartita showed a (negative) response to removals at the recruitment stage. For growth, the removal treatment effect was significant and positive for two species, Poa secunda and Pseudoroegneria spicata, indicating that the baseline model underestimated interspecific competition. For all three grass species, population models based on the vital rate regressions that included removal effects projected 1.4 to 3-fold increases in equilibrium population size relative to the baseline model (no removal effects). However, we found no evidence of higher response to removal in quadrats with higher pretreatment cover of A. tripartita, or by plants experiencing higher pre-treatment crowding by A. tripartita, raising questions about the mechanisms driving the positive response to removal. While our results show the value of combining observations with a simple removal experiment, more tightly controlled experiments focused on underlying mechanisms may be required to conclusively validate or reject predictions from phenomenological models. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. History, ethics, advantages and limitations of experimental models for hepatic ablation.

    PubMed

    Ong, Seok Ling; Gravante, Gianpiero; Metcalfe, Matthew S; Dennison, Ashley R

    2013-01-14

    Numerous techniques developed in medicine require careful evaluation to determine their indications, limitations and potential side effects prior to their clinical use. At present this generally involves the use of animal models which is undesirable from an ethical standpoint, requires complex and time-consuming authorization, and is very expensive. This process is exemplified in the development of hepatic ablation techniques, starting experiments on explanted livers and progressing to safety and efficacy studies in living animals prior to clinical studies. The two main approaches used are ex vivo isolated non-perfused liver models and in vivo animal models. Ex vivo non perfused models are less expensive, easier to obtain but not suitable to study the heat sink effect or experiments requiring several hours. In vivo animal models closely resemble clinical subjects but often are expensive and have small sample sizes due to ethical guidelines. Isolated perfused ex vivo liver models have been used to study drug toxicity, liver failure, organ transplantation and hepatic ablation and combine advantages of both previous models.

  9. Pistol shooting accuracy as dependent on experience, eyes being opened and available viewing time.

    PubMed

    Goonetilleke, Ravindra S; Hoffmann, Errol R; Lau, Wing Chung

    2009-05-01

    A study of the shooting accuracy of three groups of pistol shooters is reported. The groups included (i) experienced gas pistol shooters; (ii) persons with experience in video shooting games; and (iii) persons with no shooting experience. The viewing time was varied in the tests. The results showed that experience had a significant effect on the mean and root mean square (RMS) shooting errors at the target. The results also showed that the viewing time does not need to exceed about 2s for an experienced pistol shooter and about 3s for a novice shooter to reach the best performance. Two models for the effects of limited viewing time are proposed; both models fit the data well when the viewing time is less than about 2s. The results indicated that the differences occurring with varying levels of experience are due to postural balance and not due to the aiming or cognitive component of the task.

  10. Accessing world knowledge: evidence from N400 and reaction time priming.

    PubMed

    Chwilla, Dorothee J; Kolk, Herman H J

    2005-12-01

    How fast are we in accessing world knowledge? In two experiments, we tested for priming for word triplets that described a conceptual script (e.g., DIRECTOR-BRIBE-DISMISSAL) but were not associatively related and did not share a category relationship. Event-related brain potentials were used to track the time course at which script information becomes available. In Experiment 1, in which participants made lexical decisions, we found a facilitation for script-related relative to unrelated triplets, as indicated by (i) a decrease in both reaction time and errors, and (ii) an N400-like priming effect. In Experiment 2, we further explored the locus of script priming by increasing the contribution of meaning integration processes. The participants' task was to indicate whether the three words presented a plausible scenario. Again, an N400 script priming effect was obtained. Directing attention to script relations was effective in enhancing the N400 effect. The time course of the N400 effect was similar to that of the standard N400 effect to semantic relations. The present results show that script priming can be obtained in the visual modality, and that script information is immediately accessed and integrated with context. This supports the view that script information forms a central aspect of word meaning. The RT and N400 script priming effects reported in this article are problematic for most current semantic priming models, like spreading activation models, expectancy models, and task-specific semantic matching/integration models. They support a view in which there is no clear cutoff point between semantic knowledge and world knowledge.

  11. Global Effects of SuperParameterization on Hydro-Thermal Land-Atmosphere Coupling on Multiple Timescales and an Amplification of the Bowen Ratio

    NASA Astrophysics Data System (ADS)

    Qin, H.; Pritchard, M. S.; Kooperman, G. J.; Parishani, H.

    2017-12-01

    Conventional General Circulation Models (GCMs) in the Global Land-Atmosphere Coupling Experiment (GLACE) tend to produce overly strong Land-Atmosphere coupling (L-A coupling) strength. We investigate the effects of cloud SuperParameterization (SP) on L-A coupling on timescales longer than the diurnal where it has been previously shown to have a strong effect. Using the Community Atmosphere Model v3.5 (CAM3.5) and its SuperParameterized counterpart SPCAM3.5, we conducted experiments following the GLACE and Atmospheric Model Intercomparison Project (AMIP) protocols. On synoptic-to-subseasonal timescales, SP significantly mutes hydrologic L-A coupling on a global scale, through the atmospheric segment. But on longer seasonal timescales, SP does not exhibit detectable effects on hydrologic L-A coupling. Two regional effects of SP on thermal L-A coupling are also discovered and explored. Over the Arabian Peninsula, SP strikingly reduces thermal L-A coupling due to a control by mean regional rainfall reduction. Over the Southwestern US and Northern Mexico, however, SP remarkably enhances the thermal L-A coupling independent of rainfall or soil moisture. We argue that the cause may be a previously unrecognized effect of SP to amplify the simulated Bowen ratio. Not only does this help reconcile a puzzling local enhancement of thermal L-A coupling over the Southwestern US, but it is also demonstrated to be a robust, global effect of SP over land that is independent of model version and experiment design, and that has important consequences for climate change prediction.

  12. Bayesian cross-entropy methodology for optimal design of validation experiments

    NASA Astrophysics Data System (ADS)

    Jiang, X.; Mahadevan, S.

    2006-07-01

    An important concern in the design of validation experiments is how to incorporate the mathematical model in the design in order to allow conclusive comparisons of model prediction with experimental output in model assessment. The classical experimental design methods are more suitable for phenomena discovery and may result in a subjective, expensive, time-consuming and ineffective design that may adversely impact these comparisons. In this paper, an integrated Bayesian cross-entropy methodology is proposed to perform the optimal design of validation experiments incorporating the computational model. The expected cross entropy, an information-theoretic distance between the distributions of model prediction and experimental observation, is defined as a utility function to measure the similarity of two distributions. A simulated annealing algorithm is used to find optimal values of input variables through minimizing or maximizing the expected cross entropy. The measured data after testing with the optimum input values are used to update the distribution of the experimental output using Bayes theorem. The procedure is repeated to adaptively design the required number of experiments for model assessment, each time ensuring that the experiment provides effective comparison for validation. The methodology is illustrated for the optimal design of validation experiments for a three-leg bolted joint structure and a composite helicopter rotor hub component.

  13. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    ERIC Educational Resources Information Center

    Smith, Rachel; Cantrell, Kevin

    2007-01-01

    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  14. The Coriolis Effect: A Model for Student Involvement

    ERIC Educational Resources Information Center

    Exline, Joseph D.

    1977-01-01

    Lists materials and procedures for constructing a model that demonstrates certain aspects of the Coriolis effect. Materials include an electric drill motor, voltage control, toy dart gun and darts, wood blocks of varying dimensions. Includes description of an experiment illustrating relationship between speed of rotation and amount of apparent…

  15. Effects of Learning Support in Simulation-Based Physics Learning

    ERIC Educational Resources Information Center

    Chang, Kuo-En; Chen, Yu-Lung; Lin, He-Yan; Sung, Yao-Ting

    2008-01-01

    This paper describes the effects of learning support on simulation-based learning in three learning models: experiment prompting, a hypothesis menu, and step guidance. A simulation learning system was implemented based on these three models, and the differences between simulation-based learning and traditional laboratory learning were explored in…

  16. Project Physics Tests 5, Models of the Atom.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 5 are presented in this booklet. Included are 70 multiple-choice and 23 problem-and-essay questions. Concepts of atomic model are examined on aspects of relativistic corrections, electron emission, photoelectric effects, Compton effect, quantum theories, electrolysis experiments, atomic number and mass,…

  17. Methods That Matter in Addressing Cultural Diversity with Teacher Candidates

    ERIC Educational Resources Information Center

    Acquah, Emmanuel O.; Commins, Nancy L.

    2017-01-01

    Drawing on a combination of prior experience, theoretical stance, and intuition, along with pedagogical practices identified to be effective in addressing diversity with teacher candidates, a model for teaching multicultural education to teacher candidates was designed. This study examined how particular elements of this model were effective in…

  18. Statistical strategies for averaging EC50 from multiple dose-response experiments.

    PubMed

    Jiang, Xiaoqi; Kopp-Schneider, Annette

    2015-11-01

    In most dose-response studies, repeated experiments are conducted to determine the EC50 value for a chemical, requiring averaging EC50 estimates from a series of experiments. Two statistical strategies, the mixed-effect modeling and the meta-analysis approach, can be applied to estimate average behavior of EC50 values over all experiments by considering the variabilities within and among experiments. We investigated these two strategies in two common cases of multiple dose-response experiments in (a) complete and explicit dose-response relationships are observed in all experiments and in (b) only in a subset of experiments. In case (a), the meta-analysis strategy is a simple and robust method to average EC50 estimates. In case (b), all experimental data sets can be first screened using the dose-response screening plot, which allows visualization and comparison of multiple dose-response experimental results. As long as more than three experiments provide information about complete dose-response relationships, the experiments that cover incomplete relationships can be excluded from the meta-analysis strategy of averaging EC50 estimates. If there are only two experiments containing complete dose-response information, the mixed-effects model approach is suggested. We subsequently provided a web application for non-statisticians to implement the proposed meta-analysis strategy of averaging EC50 estimates from multiple dose-response experiments.

  19. Laboratory-scale experiments and numerical modeling of cosolvent flushing of multi-component NAPLs in saturated porous media

    NASA Astrophysics Data System (ADS)

    Agaoglu, Berken; Scheytt, Traugott; Copty, Nadim K.

    2012-10-01

    This study examines the mechanistic processes governing multiphase flow of a water-cosolvent-NAPL system in saturated porous media. Laboratory batch and column flushing experiments were conducted to determine the equilibrium properties of pure NAPL and synthetically prepared NAPL mixtures as well as NAPL recovery mechanisms for different water-ethanol contents. The effect of contact time was investigated by considering different steady and intermittent flow velocities. A modified version of multiphase flow simulator (UTCHEM) was used to compare the multiphase model simulations with the column experiment results. The effect of employing different grid geometries (1D, 2D, 3D), heterogeneity and different initial NAPL saturation configurations was also examined in the model. It is shown that the change in velocity affects the mass transfer rate between phases as well as the ultimate NAPL recovery percentage. The experiments with low flow rate flushing of pure NAPL and the 3D UTCHEM simulations gave similar effluent concentrations and NAPL cumulative recoveries. Model simulations over-estimated NAPL recovery for high specific discharges and rate-limited mass transfer, suggesting a constant mass transfer coefficient for the entire flushing experiment may not be valid. When multi-component NAPLs are present, the dissolution rate of individual organic compounds (namely, toluene and benzene) into the ethanol-water flushing solution is found not to correlate with their equilibrium solubility values.

  20. Grounding the Symbols for Place Value: Evidence from Training and Long-Term Exposure to Base-10 Models

    ERIC Educational Resources Information Center

    Mix, Kelly S.; Smith, Linda B.; Stockton, Jerri DaSha; Cheng, Yi-Ling; Barterian, Justin A.

    2017-01-01

    Two experiments examined whether concrete models support place value learning. In Experiment 1 (N = 149), 7-year-olds were trained with either a) symbols alone or b) symbols and base-10 blocks. Children in both groups showed significant growth overall, but there were specific effects favoring one training type over another. Symbols-only training…

  1. Modeling and Recovery of Iron (Fe) from Red Mud by Coal Reduction

    NASA Astrophysics Data System (ADS)

    Zhao, Xiancong; Li, Hongxu; Wang, Lei; Zhang, Lifeng

    Recovery of Fe from red mud has been studied using statistically designed experiments. The effects of three factors, namely: reduction temperature, reduction time and proportion of additive on recovery of Fe have been investigated. Experiments have been carried out using orthogonal central composite design and factorial design methods. A model has been obtained through variance analysis at 92.5% confidence level.

  2. The effect of inquiry-based learning experiences on adolescents' science-related career aspiration in the Finnish context

    NASA Astrophysics Data System (ADS)

    Kang, Jingoo; Keinonen, Tuula

    2017-08-01

    Much research has been conducted to investigate the effects of inquiry-based learning on students' attitude towards science and future involvement in the science field, but few of them conducted in-depth studies including young learners' socio-cognitive background to explore mechanisms which explain how inquiry experiences influence on career choices. Hence, the aim of this study was to investigate in what ways and to what extent the inquiry learning experiences in school science affect students' future career orientation in the context of socio-cognitive mechanisms based on socio-cognitive career theory(SCCT). For the purpose, Programme for International Student Assessment (PISA) 2015 data were used focusing on science literacy, and the sample of Finnish 15-year-old students (N = 5782) was analysed by structural equation modelling with the hypothesised Inquiry-SCCT model. The results of the study showed that inquiry learning experiences were indicated as a positive predictor for the students' career aspiration, and most of its effects were mediated by outcome expectations. Indeed, although self-efficacy and interest in learning science indicated positive correlations with future aspiration, outcome expectation presented the highest correlation with the science-related career. Gender differences were found in the model, but girls indicated higher outcome expectation and career aspiration than boys in Finland.

  3. Evaluating models of object-decision priming: evidence from event-related potential repetition effects.

    PubMed

    Soldan, Anja; Mangels, Jennifer A; Cooper, Lynn A

    2006-03-01

    This study was designed to differentiate between structural description and bias accounts of performance in the possible/impossible object-decision test. Two event-related potential (ERP) studies examined how the visual system processes structurally possible and impossible objects. Specifically, the authors investigated the effects of object repetition on a series of early posterior components during structural (Experiment 1) and functional (Experiment 2) encoding and the relationship of these effects to behavioral measures of priming. In both experiments, the authors found repetition enhancement of the posterior N1 and N2 for possible objects only. In addition, the magnitude of the N1 repetition effect for possible objects was correlated with priming for possible objects. Although the behavioral results were more ambiguous, these ERP results fail to support bias models that hold that both possible and impossible objects are processed similarly in the visual system. Instead, they support the view that priming is supported by a structural description system that encodes the global 3-dimensional structure of an object.

  4. Pavlovian control of cross-tolerance between pentobarbital and ethanol.

    PubMed

    Cappell, H; Roach, C; Poulos, C X

    1981-01-01

    Tolerance to several effects of a number of drugs has been shown to depend on Pavlovian conditioning processes. Experiment I extended the compensatory conditioning model (Siegel 1975) to tolerance to the hypothermic effect of pentobarbital (30 mg/kg). In Experiment I, rats that acquired hypothermic tolerance in one environment did not display tolerance when tested in an environment not previously associated with drug administration. In Experiment II, rats were made tolerant to the hypothermic effect of pentobarbital (30 mg/kg) and tested for cross-tolerance to ethanol (2.5 g/kg). Cross-tolerance was observed, but it was significantly reduced if the test was in an environment different from the one in which tolerance to pentobarbital was originally acquired. Thus, the compensatory conditioning model accounts for at least part of the tolerance and cross-tolerance to the thermic effects of alcohol and pentobarbital. The physiological processes in the CNS underlying tolerance and cross-tolerance for these drugs, therefore, are controlled by associative processes.

  5. The propagation of sound in tunnels

    NASA Astrophysics Data System (ADS)

    Li, Kai Ming; Iu, King Kwong

    2002-11-01

    The sound propagation in tunnels is addressed theoretically and experimentally. In many previous studies, the image source method is frequently used. However, these early theoretical models are somewhat inadequate because the effect of multiple reflections in long enclosures is often modeled by the incoherent summation of contributions from all image sources. Ignoring the phase effect, these numerical models are unlikely to be satisfactory for predicting the intricate interference patterns due to contributions from each image source. In the present paper, the interference effect is incorporated by summing the contributions from the image sources coherently. To develop a simple numerical model, tunnels are represented by long rectangular enclosures with either geometrically reflecting or impedance boundaries. Scale model experiments are conducted for the validation of the numerical model. In some of the scale model experiments, the enclosure walls are lined with a carpet for simulating the impedance boundary condition. Large-scale outdoor measurements have also been conducted in two tunnels designed originally for road traffic use. It has been shown that the proposed numerical model agrees reasonably well with experimental data. [Work supported by the Research Grants Council, The Industry Department, NAP Acoustics (Far East) Ltd., and The Hong Kong Polytechnic University.

  6. Dynamic interactions between visual working memory and saccade target selection

    PubMed Central

    Schneegans, Sebastian; Spencer, John P.; Schöner, Gregor; Hwang, Seongmin; Hollingworth, Andrew

    2014-01-01

    Recent psychophysical experiments have shown that working memory for visual surface features interacts with saccadic motor planning, even in tasks where the saccade target is unambiguously specified by spatial cues. Specifically, a match between a memorized color and the color of either the designated target or a distractor stimulus influences saccade target selection, saccade amplitudes, and latencies in a systematic fashion. To elucidate these effects, we present a dynamic neural field model in combination with new experimental data. The model captures the neural processes underlying visual perception, working memory, and saccade planning relevant to the psychophysical experiment. It consists of a low-level visual sensory representation that interacts with two separate pathways: a spatial pathway implementing spatial attention and saccade generation, and a surface feature pathway implementing color working memory and feature attention. Due to bidirectional coupling between visual working memory and feature attention in the model, the working memory content can indirectly exert an effect on perceptual processing in the low-level sensory representation. This in turn biases saccadic movement planning in the spatial pathway, allowing the model to quantitatively reproduce the observed interaction effects. The continuous coupling between representations in the model also implies that modulation should be bidirectional, and model simulations provide specific predictions for complementary effects of saccade target selection on visual working memory. These predictions were empirically confirmed in a new experiment: Memory for a sample color was biased toward the color of a task-irrelevant saccade target object, demonstrating the bidirectional coupling between visual working memory and perceptual processing. PMID:25228628

  7. Reproducible computational biology experiments with SED-ML - The Simulation Experiment Description Markup Language

    PubMed Central

    2011-01-01

    Background The increasing use of computational simulation experiments to inform modern biological research creates new challenges to annotate, archive, share and reproduce such experiments. The recently published Minimum Information About a Simulation Experiment (MIASE) proposes a minimal set of information that should be provided to allow the reproduction of simulation experiments among users and software tools. Results In this article, we present the Simulation Experiment Description Markup Language (SED-ML). SED-ML encodes in a computer-readable exchange format the information required by MIASE to enable reproduction of simulation experiments. It has been developed as a community project and it is defined in a detailed technical specification and additionally provides an XML schema. The version of SED-ML described in this publication is Level 1 Version 1. It covers the description of the most frequent type of simulation experiments in the area, namely time course simulations. SED-ML documents specify which models to use in an experiment, modifications to apply on the models before using them, which simulation procedures to run on each model, what analysis results to output, and how the results should be presented. These descriptions are independent of the underlying model implementation. SED-ML is a software-independent format for encoding the description of simulation experiments; it is not specific to particular simulation tools. Here, we demonstrate that with the growing software support for SED-ML we can effectively exchange executable simulation descriptions. Conclusions With SED-ML, software can exchange simulation experiment descriptions, enabling the validation and reuse of simulation experiments in different tools. Authors of papers reporting simulation experiments can make their simulation protocols available for other scientists to reproduce the results. Because SED-ML is agnostic about exact modeling language(s) used, experiments covering models from different fields of research can be accurately described and combined. PMID:22172142

  8. Harm to Those Who Serve: Effects of Direct and Vicarious Customer-Initiated Workplace Aggression.

    PubMed

    Dupré, Kathryne E; Dawe, Kimberly-Anne; Barling, Julian

    2014-09-01

    While there is a large body of research on the effects of being a direct target of workplace aggression, there is far less research on the vicarious experience of aggression at work, despite the fact that more people experience workplace aggression vicariously (i.e., observe it or hear about it) than they do directly. In this study, we develop and test a model of the effects of direct and vicarious exposure to aggression that is directed at employees by customers. Structural equation modeling provided support for the proposed model, in which direct and vicarious workplace aggression influences the perceived risk of future workplace aggression, which in turn affects organizational attachment (affective commitment and turnover intentions) and individual well-being (psychological and physical). Conceptual research and policy implications are discussed. © The Author(s) 2014.

  9. Propagation effects for land mobile satellite systems: Overview of experimental and modeling results

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Vogel, Wolfhard J.

    1992-01-01

    Models developed and experiments performed to characterize the propagation environment associated with land mobile communication using satellites are discussed. Experiments were carried out with transmitters on stratospheric balloons, remotely piloted aircraft, helicopters, and geostationary satellites. This text is comprised of compiled experimental results for the expressed use of communications engineers, designers of planned Land Mobile Satellite Systems (LMSS), and modelers of propagation effects. The results presented here are mostly derived from systematic studies of propagation effects for LMSS geometries in the United States associated with rural and suburban regions. Where applicable, the authors also draw liberally from the results of other related investigations in Canada, Europe, and Australia. Frequencies near 1500 MHz are emphasized to coincide with frequency bands allocated for LMSS by the International Telecommunication Union, although earlier experimental work at 870 MHz is also included.

  10. Effects of rubber shock absorber on the flywheel micro vibration in the satellite imaging system

    NASA Astrophysics Data System (ADS)

    Deng, Changcheng; Mu, Deqiang; Jia, Xuezhi; Li, Zongxuan

    2016-12-01

    When a satellite is in orbit, its flywheel will generate micro vibration and affect the imaging quality of the camera. In order to reduce this effect, a rubber shock absorber is used, and a numerical model and an experimental setup are developed to investigate its effect on the micro vibration in the study. An integrated model is developed for the system, and a ray tracing method is used in the modeling. The spot coordinates and displacements of the image plane are obtained, and the modulate transfer function (MTF) of the system is calculated. A satellite including a rubber shock absorber is designed, and the experiments are carried out. Both simulation and experiments results show that the MTF increases almost 10 %, suggesting the rubber shock absorber is useful to decrease the flywheel vibration.

  11. Sociality influences cultural complexity.

    PubMed

    Muthukrishna, Michael; Shulman, Ben W; Vasilescu, Vlad; Henrich, Joseph

    2014-01-07

    Archaeological and ethnohistorical evidence suggests a link between a population's size and structure, and the diversity or sophistication of its toolkits or technologies. Addressing these patterns, several evolutionary models predict that both the size and social interconnectedness of populations can contribute to the complexity of its cultural repertoire. Some models also predict that a sudden loss of sociality or of population will result in subsequent losses of useful skills/technologies. Here, we test these predictions with two experiments that permit learners to access either one or five models (teachers). Experiment 1 demonstrates that naive participants who could observe five models, integrate this information and generate increasingly effective skills (using an image editing tool) over 10 laboratory generations, whereas those with access to only one model show no improvement. Experiment 2, which began with a generation of trained experts, shows how learners with access to only one model lose skills (in knot-tying) more rapidly than those with access to five models. In the final generation of both experiments, all participants with access to five models demonstrate superior skills to those with access to only one model. These results support theoretical predictions linking sociality to cumulative cultural evolution.

  12. Sociality influences cultural complexity

    PubMed Central

    Muthukrishna, Michael; Shulman, Ben W.; Vasilescu, Vlad; Henrich, Joseph

    2014-01-01

    Archaeological and ethnohistorical evidence suggests a link between a population's size and structure, and the diversity or sophistication of its toolkits or technologies. Addressing these patterns, several evolutionary models predict that both the size and social interconnectedness of populations can contribute to the complexity of its cultural repertoire. Some models also predict that a sudden loss of sociality or of population will result in subsequent losses of useful skills/technologies. Here, we test these predictions with two experiments that permit learners to access either one or five models (teachers). Experiment 1 demonstrates that naive participants who could observe five models, integrate this information and generate increasingly effective skills (using an image editing tool) over 10 laboratory generations, whereas those with access to only one model show no improvement. Experiment 2, which began with a generation of trained experts, shows how learners with access to only one model lose skills (in knot-tying) more rapidly than those with access to five models. In the final generation of both experiments, all participants with access to five models demonstrate superior skills to those with access to only one model. These results support theoretical predictions linking sociality to cumulative cultural evolution. PMID:24225461

  13. Comparison of entrainment rates from a tank experiment with results using the one-dimensional turbulence model.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerstein, Alan R.; Sayler, B. J.; Wunsch, S.

    2010-05-01

    Recent work suggests that cloud effects remain one of the largest sources of uncertainty in model-based estimates of climate sensitivity. In particular, the entrainment rate in stratocumulus-topped mixed layers needs better models. More than thirty years ago a clever laboratory experiment was conducted by McEwan and Paltridge to examine an analog of the entrainment process at the top of stratiform clouds. Sayler and Breidenthal extended this pioneering work and determined the effect of the Richardson number on the dimensionless entrainment rate. The experiments gave hints that the interaction between molecular effects and the one-sided turbulence seems to be crucial formore » understanding entrainment. From the numerical point of view large-eddy simulation (LES) does not allow explicitly resolving all the fine scale processes at the entrainment interface. Direct numerical simulation (DNS) is limited due to the Reynolds number and is not the tool of choice for parameter studies. Therefore it is useful to investigate new modeling strategies, such as stochastic turbulence models which allow sufficient resolution at least in one dimension while having acceptable run times. We will present results of the One-Dimensional Turbulence stochastic simulation model applied to the experimental setup of Sayler and Breidenthal. The results on radiatively induced entrainment follow quite well the scaling of the entrainment rate with the Richardson number that was experimentally found for a set of trials. Moreover, we investigate the influence of molecular effects, the fluids optical properties, and the artifact of parasitic turbulence experimentally observed in the laminar layer. In the simulations the parameters are varied systematically for even larger ranges than in the experiment. Based on the obtained results a more complex parameterization of the entrainment rate than currently discussed in the literature seems to be necessary.« less

  14. Music experience influences laparoscopic skills performance.

    PubMed

    Boyd, Tanner; Jung, Inkyung; Van Sickle, Kent; Schwesinger, Wayne; Michalek, Joel; Bingener, Juliane

    2008-01-01

    Music education affects the mathematical and visuo-spatial skills of school-age children. Visuo-spatial abilities have a significant effect on laparoscopic suturing performance. We hypothesize that prior music experience influences the performance of laparoscopic suturing tasks. Thirty novices observed a laparoscopic suturing task video. Each performed 3 timed suturing task trials. Demographics were recorded. A repeated measures linear mixed model was used to examine the effects of prior music experience on suturing task time. Twelve women and 18 men completed the tasks. When adjusted for video game experience, participants who currently played an instrument performed significantly faster than those who did not (P<0.001). The model showed a significant sex by instrument interaction. Men who had never played an instrument or were currently playing an instrument performed better than women in the same group (P=0.002 and P<0.001). There was no sex difference in the performance of participants who had played an instrument in the past (P=0.29). This study attempted to investigate the effect of music experience on the laparoscopic suturing abilities of surgical novices. The visuo-spatial abilities used in laparoscopic suturing may be enhanced in those involved in playing an instrument.

  15. From theory to experimental design-Quantifying a trait-based theory of predator-prey dynamics.

    PubMed

    Laubmeier, A N; Wootton, Kate; Banks, J E; Bommarco, Riccardo; Curtsdotter, Alva; Jonsson, Tomas; Roslin, Tomas; Banks, H T

    2018-01-01

    Successfully applying theoretical models to natural communities and predicting ecosystem behavior under changing conditions is the backbone of predictive ecology. However, the experiments required to test these models are dictated by practical constraints, and models are often opportunistically validated against data for which they were never intended. Alternatively, we can inform and improve experimental design by an in-depth pre-experimental analysis of the model, generating experiments better targeted at testing the validity of a theory. Here, we describe this process for a specific experiment. Starting from food web ecological theory, we formulate a model and design an experiment to optimally test the validity of the theory, supplementing traditional design considerations with model analysis. The experiment itself will be run and described in a separate paper. The theory we test is that trophic population dynamics are dictated by species traits, and we study this in a community of terrestrial arthropods. We depart from the Allometric Trophic Network (ATN) model and hypothesize that including habitat use, in addition to body mass, is necessary to better model trophic interactions. We therefore formulate new terms which account for micro-habitat use as well as intra- and interspecific interference in the ATN model. We design an experiment and an effective sampling regime to test this model and the underlying assumptions about the traits dominating trophic interactions. We arrive at a detailed sampling protocol to maximize information content in the empirical data obtained from the experiment and, relying on theoretical analysis of the proposed model, explore potential shortcomings of our design. Consequently, since this is a "pre-experimental" exercise aimed at improving the links between hypothesis formulation, model construction, experimental design and data collection, we hasten to publish our findings before analyzing data from the actual experiment, thus setting the stage for strong inference.

  16. A large-scale deforestation experiment: Effects of patch area and isolation on Amazon birds

    USGS Publications Warehouse

    Ferraz, G.; Nichols, J.D.; Hines, J.E.; Stouffer, P.C.; Bierregaard, R.O.; Lovejoy, T.E.

    2007-01-01

    As compared with extensive contiguous areas, small isolated habitat patches lack many species. Some species disappear after isolation; others are rarely found in any small patch, regardless of isolation. We used a 13-year data set of bird captures from a large landscape-manipulation experiment in a Brazilian Amazon forest to model the extinction-colonization dynamics of 55 species and tested basic predictions of island biogeography and metapopulation theory. From our models, we derived two metrics of species vulnerability to changes in isolation and patch area. We found a strong effect of area and a variable effect of isolation on the predicted patch occupancy by birds.

  17. The effects of retrieval ease on health issue judgments: implications for campaign strategies.

    PubMed

    Chang, Chingching

    2010-12-01

    This paper examines the effects of retrieving information about a health ailment on judgments of the perceived severity of the disease and self-efficacy regarding prevention and treatment. The literature on metacognition suggests that recall tasks render two types of information accessible: the retrieved content, and the subjective experience of retrieving the content. Both types of information can influence judgments. Content-based thinking models hold that the more instances of an event people can retrieve, the higher they will estimate the frequency of the event to be. In contrast, experience-based thinking models suggest that when people experience difficulty in retrieving information regarding an event, they rate the event as less likely to occur. In the first experiment, ease of retrieval was manipulated by asking participants to list either a high or low number of consequences of an ailment. As expected, retrieval difficulty resulted in lower perceived disease severity. In the second experiment, ease of retrieval was manipulated by varying the number of disease prevention or treatment measures participants attempted to list. As predicted, retrieval difficulty resulted in lower self-efficacy regarding prevention and treatment. In experiment three, when information regarding a health issue was made accessible by exposure to public service announcements (PSAs), ease-of-retrieval effects were attenuated. Finally, in experiment four, exposure to PSAs encouraged content-based judgments when the issue was of great concern.

  18. Startle stimuli reduce the internal model control in discrete movements.

    PubMed

    Wright, Zachary A; Rogers, Mark W; MacKinnon, Colum D; Patton, James L

    2009-01-01

    A well known and major component of movement control is the feedforward component, also known as the internal model. This model predicts and compensates for expected forces seen during a movement, based on recent experience, so that a well-learned task such as reaching to a target can be executed in a smooth straight manner. It has recently been shown that the state of preparation of planned movements can be tested using a startling acoustic stimulus (SAS). SAS, presented 500, 250 or 0 ms before the expected "go" cue resulted in the early release of the movement trajectory associated with the after-effects of the force field training (i.e. the internal model). In a typical motor adaptation experiment with a robot-applied force field, we tested if a SAS stimulus influences the size of after-effects that are typically seen. We found that in all subjects the after-effect magnitudes were significantly reduced when movements were released by SAS, although this effect was not further modulated by the timing of SAS. Reduced after-effects reveal at least partial existence of learned preparatory control, and identify startle effects that could influence performance in tasks such as piloting, teleoperation, and sports.

  19. Closing the loop on improvement: Packaging experience in the Software Engineering Laboratory

    NASA Technical Reports Server (NTRS)

    Waligora, Sharon R.; Landis, Linda C.; Doland, Jerry T.

    1994-01-01

    As part of its award-winning software process improvement program, the Software Engineering Laboratory (SEL) has developed an effective method for packaging organizational best practices based on real project experience into useful handbooks and training courses. This paper shares the SEL's experience over the past 12 years creating and updating software process handbooks and training courses. It provides cost models and guidelines for successful experience packaging derived from SEL experience.

  20. Timeslice experiments for understanding regional climate projections: applications to the tropical hydrological cycle and European winter circulation

    NASA Astrophysics Data System (ADS)

    Chadwick, Robin; Douville, Hervé; Skinner, Christopher B.

    2017-11-01

    A set of atmosphere-only timeslice experiments are described, designed to examine the processes that cause regional climate change and inter-model uncertainty in coupled climate model responses to CO_2 forcing. The timeslice experiments are able to reproduce the pattern of regional climate change in the coupled models, and are applied here to two cases where inter-model uncertainty in future projections is large: the tropical hydrological cycle, and European winter circulation. In tropical forest regions, the plant physiological effect is the largest cause of hydrological cycle change in the two models that represent this process. This suggests that the CMIP5 ensemble mean may be underestimating the magnitude of water cycle change in these regions, due to the inclusion of models without the plant effect. SST pattern change is the dominant cause of precipitation and circulation change over the tropical oceans, and also appears to contribute to inter-model uncertainty in precipitation change over tropical land regions. Over Europe and the North Atlantic, uniform SST increases drive a poleward shift of the storm-track. However this does not consistently translate into an overall polewards storm-track shift, due to large circulation responses to SST pattern change, which varies across the models. Coupled model SST biases influence regional rainfall projections in regions such as the Maritime Continent, and so projections in these regions should be treated with caution.

  1. Model Minority Stereotyping, Perceived Discrimination, and Adjustment Among Adolescents from Asian American Backgrounds.

    PubMed

    Kiang, Lisa; Witkow, Melissa R; Thompson, Taylor L

    2016-07-01

    The model minority image is a common and pervasive stereotype that Asian American adolescents must navigate. Using multiwave data from 159 adolescents from Asian American backgrounds (mean age at initial recruitment = 15.03, SD = .92; 60 % female; 74 % US-born), the current study targeted unexplored aspects of the model minority experience in conjunction with more traditionally measured experiences of negative discrimination. When examining normative changes, perceptions of model minority stereotyping increased over the high school years while perceptions of discrimination decreased. Both experiences were not associated with each other, suggesting independent forms of social interactions. Model minority stereotyping generally promoted academic and socioemotional adjustment, whereas discrimination hindered outcomes. Moreover, in terms of academic adjustment, the model minority stereotype appears to protect against the detrimental effect of discrimination. Implications of the complex duality of adolescents' social interactions are discussed.

  2. Diffusion Filters for Variational Data Assimilation of Sea Surface Temperature in an Intermediate Climate Model

    DTIC Science & Technology

    2015-01-01

    over data-dense regions. After that, a perfect twin data assimilation experiment framework is designed to study the effect of the GDF on the state...is designed to study the effect of the GDF on the state estimation based on an intermediate coupled model. In this framework, the assimilation model...observation. Considering = , (4) is equal to () = 1 2 + 1 2 ( − ) −1 ( − ) . (5) The effect of in (5) can

  3. Effectiveness of the clinical teaching associate model to improve clinical learning outcomes: a randomized controlled trial.

    PubMed

    Parchebafieh, Samaneh; Gholizadeh, Leila; Lakdizaji, Sima; Ghiasvandiyan, Shahrzad; Davoodi, Arefeh

    2014-01-01

    This study examined the effectiveness of the clinical teaching associate (CTA) model to improve clinical learning outcomes in nursing students. Students were randomly allocated to either the CTA (n = 28) or traditional training group (n = 32), and their clinical knowledge, skills, and satisfaction with the learning experience were assessed and compared. The results showed that the CTA model was equally effective in improving clinical knowledge, skills, and satisfaction of nursing students.

  4. Comparison of Data on Mutation Frequencies of Mice Caused by Radiation with Low Dose Model

    NASA Astrophysics Data System (ADS)

    Manabe, Yuichiro; Bando, Masako

    2013-09-01

    We propose low dose (LD) model, the extension of LDM model which was proposed in the previous paper [Y. Manabe et al.: J. Phys. Soc. Jpn. 81 (2012) 104004] to estimate biological damage caused by irradiation. LD model takes account of cell death effect in addition to the proliferation, apoptosis, repair which were included in LDM model. As a typical example of estimation, we apply LD model to the experiment of mutation frequency on the responses induced by the exposure to low levels of ionizing radiation. The most famous and extensive experiments are those summarized by Russell and Kelly [Proc. Natl. Acad. Sci. U.S.A. 79 (1982) 539], which are known as ``mega-mouse project''. This provides us with important information of the frequencies of transmitted specific-locus mutations induced in mouse spermatogonia stem-cells. It is found that the numerical results of the mutation frequency of mice are in reasonable agreement with the experimental data: the LD model reproduces the total dose and dose rate dependence of data reasonably. In order to see such dose-rate dependence more explicitly, we introduce the dose-rate effectiveness factor (DREF). This represents a sort of dose rate dependent effect, which are to be competitive with proliferation effect of broken cells induced by irradiation.

  5. Multiphysics modeling of two-phase film boiling within porous corrosion deposits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jin, Miaomiao, E-mail: mmjin@mit.edu; Short, Michael, E-mail: hereiam@mit.edu

    2016-07-01

    Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits.more » Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys. - Highlights: • A two-phase model of CRUD's effects on fuel cladding is developed and improved. • This model eliminates the formerly erroneous assumption of wick boiling. • Higher fuel cladding temperatures are predicted when accounting for two-phase flow. • Double-peaks in thermal conductivity vs. heat flux in experiments are explained. • A “double dryout” mechanism in CRUD is proposed based on the model and experiments.« less

  6. The effect of data structures on INGRES performance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Creighton, J.R.

    1987-01-01

    Computer experiments were conducted to determine the effect of using Heap, ISAM, Hash and B-tree data structures for INGRES relations. Average times for retrieve, append and update were determined for searches by unique key and non-key data. The experiments were conducted on relations of approximately 1000 tuples of 332 byte width. Multiple operations were performed, where appropriate, to obtain average times. Simple models of the data structures are presented and shown to be consistent with experimental results. The models can be used to predict performance, and to select the appropriate data structure for various applications.

  7. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.

  8. Numerical experiments on short-term meteorological effects on solar variability

    NASA Technical Reports Server (NTRS)

    Somerville, R. C. J.; Hansen, J. E.; Stone, P. H.; Quirk, W. J.; Lacis, A. A.

    1975-01-01

    A set of numerical experiments was conducted to test the short-range sensitivity of a large atmospheric general circulation model to changes in solar constant and ozone amount. On the basis of the results of 12-day sets of integrations with very large variations in these parameters, it is concluded that realistic variations would produce insignificant meteorological effects. Any causal relationships between solar variability and weather, for time scales of two weeks or less, rely upon changes in parameters other than solar constant or ozone amounts, or upon mechanisms not yet incorporated in the model.

  9. A 3D unstructured grid nearshore hydrodynamic model based on the vortex force formalism

    NASA Astrophysics Data System (ADS)

    Zheng, Peng; Li, Ming; van der A, Dominic A.; van der Zanden, Joep; Wolf, Judith; Chen, Xueen; Wang, Caixia

    2017-08-01

    A new three-dimensional nearshore hydrodynamic model system is developed based on the unstructured-grid version of the third generation spectral wave model SWAN (Un-SWAN) coupled with the three-dimensional ocean circulation model FVCOM to enable the full representation of the wave-current interaction in the nearshore region. A new wave-current coupling scheme is developed by adopting the vortex-force (VF) scheme to represent the wave-current interaction. The GLS turbulence model is also modified to better reproduce wave-breaking enhanced turbulence, together with a roller transport model to account for the effect of surface wave roller. This new model system is validated first against a theoretical case of obliquely incident waves on a planar beach, and then applied to three test cases: a laboratory scale experiment of normal waves on a beach with a fixed breaker bar, a field experiment of oblique incident waves on a natural, sandy barred beach (Duck'94 experiment), and a laboratory study of normal-incident waves propagating around a shore-parallel breakwater. Overall, the model predictions agree well with the available measurements in these tests, illustrating the robustness and efficiency of the present model for very different spatial scales and hydrodynamic conditions. Sensitivity tests indicate the importance of roller effects and wave energy dissipation on the mean flow (undertow) profile over the depth. These tests further suggest to adopt a spatially varying value for roller effects across the beach. In addition, the parameter values in the GLS turbulence model should be spatially inhomogeneous, which leads to better prediction of the turbulent kinetic energy and an improved prediction of the undertow velocity profile.

  10. The Effect of Alcohol Abuse and Dependence and School Experiences on Depression: A National Study of Adolescents

    ERIC Educational Resources Information Center

    Merianos, Ashley L.; King, Keith A.; Vidourek, Rebecca A.; Hardee, Angelica M.

    2016-01-01

    The study purpose was to examine the effect alcohol abuse/dependence and school experiences have on depression among a nationwide sample of adolescents. A secondary analysis of the 2013 National Survey on Drug Use and Health was conducted. The results of the final multivariable logistic regression model revealed that adolescents who reported…

  11. Experiments in free shear flows: Status and needs for the future

    NASA Technical Reports Server (NTRS)

    Kline, S. J.; Coles, D. E.; Eggers, J. M.; Harsha, P. T.

    1973-01-01

    Experiments in free turbulent flows are recommended with the primary concern placed on classical flows in order to augment understanding and for model building. Five classes of experiments dealing with classical free turbulent flows are outlined and proposed as being of particular significance for the near future. These classes include the following: (1) Experiments clarifying the effect of density variation owing to use of different gases, with and without the additional effect of density variation due to high Mach number or other effects; (2) experiments clarifying the role and importance of various parameters which determine the behavior of the near field as well as the condictions under which any of these parameters can be neglected; (3) experiments determining the cumulative effect of initial conditions in terms of distance to fully established flow; (4) experiments for cases where two layers of distinctly different initial turbulence structure flow side by side at the same mean speed; and (5) experiment using contemporary experimental techniques to study structure in free turbulent shear flows in order to compliment and support contemporary work on boundary layers.

  12. Employment programs and professionals with a disability.

    PubMed

    Donelly, Michelle; Given, Fiona

    2010-01-01

    It is unclear whether or not open (competitive) employment programs are meeting the needs of the growing numbers of people with a disability seeking professional employment. To understand and describe the experience of a newly graduated professional (Michael) who was seeking open employment support and to analyze those experiences in relation to principles of effective open employment support. Michael a recently graduated accountant who also has a physical disability. A review of the literature was undertaken to identify recommended principles and practices for the conduct of effective open employment and career development programs. A case study was used to describe Michael's experiences as he sought professional employment. Michael's experiences were analysed in relation to recommended principles and practice. The analysis confirmed that the concerns Michael experienced about the supported employment program compromised the effectiveness of the support he received. Employment services based on models of independent living, disability service standards and remediation are likely to focus on the 'pathology' or performance 'deficits' of the person with a disability. Successful open employment models are more likely to place pre-eminence on the perspective of the person with a disability and effective practices for securing employment.

  13. The Roles of Ethnicity, Sex, and Parental Pain Modeling in Rating of Experienced and Imagined Pain Events

    PubMed Central

    Boissoneault, Jeff; Bunch, Jennifer R.; Robinson, Michael

    2015-01-01

    To investigate the association of ethnicity, sex, and parental pain modeling on the evaluation of experienced and imagined painful events, 173 healthy volunteers (96 women) completed the Prior Pain Experience Questionnaire, a 79-question assessment of the intensity of painful events, and a questionnaire regarding exposure to parental pain models. Consistent with existing literature, greater ratings of experienced pain were noted among Black vs. White participants. Parental pain modeling was associated with higher imagined pain ratings, but only when the parent matched the participant’s sex. This effect was greater among White and Asian participants than Black or Hispanic participants, implying ethno-cultural effects may moderate the influence of pain modeling on the evaluation of imagined pain events. The clinical implications of these findings, as well as the predictive ability of imagined pain ratings for determining future experiences of pain, should be investigated in future studies. PMID:26085306

  14. [The research of 10-hydroxy-2-decenoic acid on experiment hyperlipoidemic rat].

    PubMed

    Xu, Donghui; Mei, Xueting; Xu, Shibo

    2002-05-01

    To study the pharmacological effect of 10-hydroxy-2-decenoic acid(10-HDA) in experiment hyperlipoidemic rat. Preventive and therapeutic effects of 10-HDA were tested on hyperlioidemic rat model induced by high fat food. 10-HDA could reduce the content of TC, TG and beta-lioprotein, raise the content of HDL, which showed 10-HDA had preventive and therapeutic effects on hyperlipoidemic rat. 10-HDA was functional factor of preventive and therapeutic effects of royal jelly on hyperlipoidemia.

  15. Walking through doorways causes forgetting: Event structure or updating disruption?

    PubMed

    Pettijohn, Kyle A; Radvansky, Gabriel A

    2016-11-01

    According to event cognition theory, people segment experience into separate event models. One consequence of this segmentation is that when people transport objects from one location to another, memory is worse than if people move across a large location. In two experiments participants navigated through a virtual environment, and recognition memory was tested in either the presence or the absence of a location shift for objects that were recently interacted with (i.e., just picked up or set down). Of particular concern here is whether this location updating effect is due to (a) differences in retention intervals as a result of the navigation process, (b) a temporary disruption in cognitive processing that may occur as a result of the updating processes, or (c) a need to manage multiple event models, as has been suggested in prior research. Experiment 1 explored whether retention interval is driving this effect by recording travel times from the acquisition of an object and the probe time. The results revealed that travel times were similar, thereby rejecting a retention interval explanation. Experiment 2 explored whether a temporary disruption in processing is producing the effect by introducing a 3-second delay prior to the presentation of a memory probe. The pattern of results was not affected by adding a delay, thereby rejecting a temporary disruption account. These results are interpreted in the context of the event horizon model, which suggests that when there are multiple event models that contain common elements there is interference at retrieval, which compromises performance.

  16. Assessing the uncertainty of soil moisture impacts on convective precipitation using a new ensemble approach

    NASA Astrophysics Data System (ADS)

    Henneberg, Olga; Ament, Felix; Grützun, Verena

    2018-05-01

    Soil moisture amount and distribution control evapotranspiration and thus impact the occurrence of convective precipitation. Many recent model studies demonstrate that changes in initial soil moisture content result in modified convective precipitation. However, to quantify the resulting precipitation changes, the chaotic behavior of the atmospheric system needs to be considered. Slight changes in the simulation setup, such as the chosen model domain, also result in modifications to the simulated precipitation field. This causes an uncertainty due to stochastic variability, which can be large compared to effects caused by soil moisture variations. By shifting the model domain, we estimate the uncertainty of the model results. Our novel uncertainty estimate includes 10 simulations with shifted model boundaries and is compared to the effects on precipitation caused by variations in soil moisture amount and local distribution. With this approach, the influence of soil moisture amount and distribution on convective precipitation is quantified. Deviations in simulated precipitation can only be attributed to soil moisture impacts if the systematic effects of soil moisture modifications are larger than the inherent simulation uncertainty at the convection-resolving scale. We performed seven experiments with modified soil moisture amount or distribution to address the effect of soil moisture on precipitation. Each of the experiments consists of 10 ensemble members using the deep convection-resolving COSMO model with a grid spacing of 2.8 km. Only in experiments with very strong modification in soil moisture do precipitation changes exceed the model spread in amplitude, location or structure. These changes are caused by a 50 % soil moisture increase in either the whole or part of the model domain or by drying the whole model domain. Increasing or decreasing soil moisture both predominantly results in reduced precipitation rates. Replacing the soil moisture with realistic fields from different days has an insignificant influence on precipitation. The findings of this study underline the need for uncertainty estimates in soil moisture studies based on convection-resolving models.

  17. A simplified parsimonious higher order multivariate Markov chain model

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Yang, Chuan-sheng

    2017-09-01

    In this paper, a simplified parsimonious higher-order multivariate Markov chain model (SPHOMMCM) is presented. Moreover, parameter estimation method of TPHOMMCM is give. Numerical experiments shows the effectiveness of TPHOMMCM.

  18. Statistical Models for the Analysis and Design of Digital Polymerase Chain Reaction (dPCR) Experiments.

    PubMed

    Dorazio, Robert M; Hunter, Margaret E

    2015-11-03

    Statistical methods for the analysis and design of experiments using digital PCR (dPCR) have received only limited attention and have been misused in many instances. To address this issue and to provide a more general approach to the analysis of dPCR data, we describe a class of statistical models for the analysis and design of experiments that require quantification of nucleic acids. These models are mathematically equivalent to generalized linear models of binomial responses that include a complementary, log-log link function and an offset that is dependent on the dPCR partition volume. These models are both versatile and easy to fit using conventional statistical software. Covariates can be used to specify different sources of variation in nucleic acid concentration, and a model's parameters can be used to quantify the effects of these covariates. For purposes of illustration, we analyzed dPCR data from different types of experiments, including serial dilution, evaluation of copy number variation, and quantification of gene expression. We also showed how these models can be used to help design dPCR experiments, as in selection of sample sizes needed to achieve desired levels of precision in estimates of nucleic acid concentration or to detect differences in concentration among treatments with prescribed levels of statistical power.

  19. The role of labor pain and overall birth experience in the development of posttraumatic stress symptoms: a longitudinal cohort study.

    PubMed

    Garthus-Niegel, Susan; Knoph, Cecilie; von Soest, Tilmann; Nielsen, Christopher S; Eberhard-Gran, Malin

    2014-03-01

    The aim of this prospective study was to investigate the role of labor pain and overall birth experience in the development of posttraumatic stress symptoms in a comprehensive framework. The study sample (N = 1893) comprised women with a vaginal delivery and was drawn from the Akershus Birth Cohort, which targeted all women scheduled to give birth at Akershus University Hospital in Norway. Questionnaires were given at three different stages: from pregnancy weeks 17 to 32, from the maternity ward, and from 8 weeks postpartum. Data were also obtained from the hospital's birth record. Using structural equation modeling, a prospective mediation model was tested. Posttraumatic stress symptoms were significantly related to both labor pain (r = 0.23) and overall birth experience (r = 0.39). A substantial portion (33%) of the effect of labor pain on posttraumatic stress symptoms was mediated by the overall birth experience. Although the results of this study showed that both labor pain and overall birth experience played a role in the development of posttraumatic stress symptoms after childbirth, overall birth experience appeared to be the central factor. The women's birth experience was not only related to posttraumatic stress symptoms directly but also mediated a substantial portion of the effect of labor pain on posttraumatic stress symptoms. Future work should address which areas of birth experience confer protective effects on women to improve clinical care. © 2014, Copyright the Authors Journal compilation © 2014, Wiley Periodicals, Inc.

  20. By which name should I call thee? The consequences of having multiple names.

    PubMed

    Stevenage, Sarah V; Lewis, Hugh G

    2005-11-01

    The nominal competitor effect suggests that, when a person has two names associated with them, recall of either name is more difficult than if they just had one name. Drawing on a connectionist framework, this effect could arise either if multiple names were represented as being connected to a single person identity node (PIN), or if multiple names were represented as being connected via one-to-one links to multiple PINs. Whilst the latter has intuitive appeal, results from two experiments support the former architecture. Having two names connected to a single PIN not only gives rise to a nominal competitor effect (Experiment 1), but also gives rise to a familiarity enhancement effect (Experiment 2). These empirical results are simulated using an extension of Brédart, Valentine, Calder, and Gassi's (1995) connectionist architecture, which reveals that both effects hold even when the association of both names to the PIN is unequal. These results are presented in terms of a more complete model for person recognition, and the representation of semantic information within such a model is examined.

  1. Rally effects, threat, and attitude change: an integrative approach to understanding the role of emotion.

    PubMed

    Lambert, Alan J; Scherer, Laura D; Schott, John Paul; Olson, Kristina R; Andrews, Rick K; O'Brien, Thomas C; Zisser, Alison R

    2010-06-01

    Rally 'round the flag effects (J. E. Mueller, 1970) represent sudden and dramatically powerful situation-specific shifts in attitudes toward the American president. However, the extant literature has yet to fully clarify the nature of the psychological dynamics associated with this effect. These ambiguities reflect fundamental differences of opinion among scholars on some very basic questions such as whether overtly experienced emotion should mediate these attitudinal shifts or whether these changes reflect more general shifts in conservative ideology. Across 4 experiments, the authors sought to gain greater clarity on these and other important matters using a multimethod approach in which the authors varied whether participants viewed documentary footage of the 9/11 attacks (Experiments 1-2), generated autobiographical memories of that event (Experiment 3), or retrieved nonpolitical memories from their past (Experiment 4). The authors discuss the relevance of the present findings for theory and research across a variety of different theoretical and methodological paradigms, including social psychological models of threat, emotional appraisal models, and the political science literature. (c) 2010 APA, all rights reserved).

  2. Designing Experiments to Discriminate Families of Logic Models.

    PubMed

    Videla, Santiago; Konokotina, Irina; Alexopoulos, Leonidas G; Saez-Rodriguez, Julio; Schaub, Torsten; Siegel, Anne; Guziolowski, Carito

    2015-01-01

    Logic models of signaling pathways are a promising way of building effective in silico functional models of a cell, in particular of signaling pathways. The automated learning of Boolean logic models describing signaling pathways can be achieved by training to phosphoproteomics data, which is particularly useful if it is measured upon different combinations of perturbations in a high-throughput fashion. However, in practice, the number and type of allowed perturbations are not exhaustive. Moreover, experimental data are unavoidably subjected to noise. As a result, the learning process results in a family of feasible logical networks rather than in a single model. This family is composed of logic models implementing different internal wirings for the system and therefore the predictions of experiments from this family may present a significant level of variability, and hence uncertainty. In this paper, we introduce a method based on Answer Set Programming to propose an optimal experimental design that aims to narrow down the variability (in terms of input-output behaviors) within families of logical models learned from experimental data. We study how the fitness with respect to the data can be improved after an optimal selection of signaling perturbations and how we learn optimal logic models with minimal number of experiments. The methods are applied on signaling pathways in human liver cells and phosphoproteomics experimental data. Using 25% of the experiments, we obtained logical models with fitness scores (mean square error) 15% close to the ones obtained using all experiments, illustrating the impact that our approach can have on the design of experiments for efficient model calibration.

  3. Women's Self-definition in Adulthood: From a Different Model?

    ERIC Educational Resources Information Center

    Peck, Teresa A.

    1986-01-01

    Examines criticisms of existing models of adult development from both feminist and developmental psychologists. A model of women's adult self-definition is presented, based upon current research on women's adult experience. The model combines a dialectical approach, which considers the effects of social/historical factors, with a feminist…

  4. Teachers' Development Model to Authentic Assessment by Empowerment Evaluation Approach

    ERIC Educational Resources Information Center

    Charoenchai, Charin; Phuseeorn, Songsak; Phengsawat, Waro

    2015-01-01

    The purposes of this study were 1) Study teachers authentic assessment, teachers comprehension of authentic assessment and teachers needs for authentic assessment development. 2) To create teachers development model. 3) Experiment of teachers development model. 4) Evaluate effectiveness of teachers development model. The research is divided into 4…

  5. Groundwater sapping channels: Summary of effects of experiments with varied stratigraphy

    NASA Technical Reports Server (NTRS)

    Kochel, R. Craig; Simmons, David W.

    1987-01-01

    Experiments in the recirculating flume sapping box have modeled valley formation by groundwater sapping processes in a number of settings. The effects of the following parameters on sapping channel morphology were examined: surface slope; stratigraphic variations in permeability cohesion and dip; and structure of joints and dikes. These kinds of modeling experiments are particularly good for: testing concepts; developing a suite of distinctive morphologies and morphometries indicative of sapping; helping to relate process to morphology; and providing data necessary to assess the relative importance of runoff, sapping, and mass wasting processes on channel development. The observations from the flume systems can be used to help interpret features observed in terrestrial and Martian settings where sapping processes are thought to have played an important role in the development of valley networks.

  6. How people learn about causal influence when there are many possible causes: A model based on informative transitions.

    PubMed

    Derringer, Cory; Rottman, Benjamin Margolin

    2018-05-01

    Four experiments tested how people learn cause-effect relations when there are many possible causes of an effect. When there are many cues, even if all the cues together strongly predict the effect, the bivariate relation between each individual cue and the effect can be weak, which can make it difficult to detect the influence of each cue. We hypothesized that when detecting the influence of a cue, in addition to learning from the states of the cues and effect (e.g., a cue is present and the effect is present), which is hypothesized by multiple existing theories of learning, participants would also learn from transitions - how the cues and effect change over time (e.g., a cue turns on and the effect turns on). We found that participants were better able to identify positive and negative cues in an environment in which only one cue changed from one trial to the next, compared to multiple cues changing (Experiments 1A, 1B). Within a single learning sequence, participants were also more likely to update their beliefs about causal strength when one cue changed at a time ('one-change transitions') than when multiple cues changed simultaneously (Experiment 2). Furthermore, learning was impaired when the trials were grouped by the state of the effect (Experiment 3) or when the trials were grouped by the state of a cue (Experiment 4), both of which reduce the number of one-change transitions. We developed a modification of the Rescorla-Wagner algorithm to model this 'Informative Transitions' learning processes. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Mediation and Moderation of the Relationship Between Combat Experiences and Post-Traumatic Stress Symptoms in Active Duty Military Personnel.

    PubMed

    Steele, Marshall; Germain, Anne; Campbell, Justin S

    2017-05-01

    Post-traumatic stress disorder (PTSD) is a major health concern among the U.S. military population, affecting up to 12% to 24% of veterans returning from Iraq and Afghanistan. Sleep disturbances, neuroticism, and childhood trauma have all been associated with the development of PTSD in military populations, especially in relation to combat experiences. The effects of disrupted sleep and post-traumatic stress can affect the physical well-being of soldier and sailors in the field and impact them for years after deployment. This study aimed to evaluate the relationship between self-reported measures of combat experiences, PTSD symptoms, sleep, neuroticism, and childhood adversity in an active duty military population. 972 U.S. Navy Sailors serving in Afghanistan were given anonymous surveys that assess scales of combat stressors, PTSD symptoms, sleep problems, neuroticism, adverse child experiences (ACEs), and other covariates. Sleep disturbances were hypothesized as moderators, having an indirect effect on the relationship between combat experiences and PTSD symptoms. Neuroticism scores and ACEs were proposed as moderators of the combat-PTSD symptom relationship. Mediation and moderation models were developed and tested using logistic regressions. Increased number of combat experiences was found to be a significant predictor of PTSD, even when adjusting for all covariates (p < 0.05). Consistent with partial mediation, nightmares had an indirect effect on the relationship between combat experiences and PTSD symptoms in the final model (path coefficient = 0.233, 95% confidence interval = 0.036, 0.483). Neuroticism was an independent predictor of PTSD symptoms (p < 0.001), but the interaction of combat and neuroticism did not predict symptoms of PTSD. ACEs did not have a significant impact in the model as either an independent predictor or a moderating factor. These results indicate that the presence of nightmares may partially explain how traumatic combat experiences lead to the development of PTSD. The study also reaffirms neuroticism as risk factor for developing PTSD symptoms. These findings highlight the importance of sleep hygiene and operational stress models in combat situations and may help stress control professionals address risk factors associated with PTSD symptoms. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  8. Global Effects of Superparameterization on Hydrothermal Land-Atmosphere Coupling on Multiple Timescales

    NASA Astrophysics Data System (ADS)

    Qin, Hongchen; Pritchard, Michael S.; Kooperman, Gabriel J.; Parishani, Hossein

    2018-02-01

    Many conventional General Circulation Models (GCMs) in the Global Land-Atmosphere Coupling Experiment (GLACE) tend to produce what is now recognized as overly strong land-atmosphere (L-A) coupling. We investigate the effects of cloud Superparameterization (SP) on L-A coupling on timescales beyond diurnal where it has been recently shown to have a favorable muting effect hydrologically. Using the Community Atmosphere Model v3.5 (CAM3.5) and its Superparameterized counterpart SPCAM3.5, we conducted soil moisture interference experiments following the GLACE and Atmospheric Model Intercomparison Project (AMIP) protocols. The results show that, on weekly-to-subseasonal timescales, SP also mutes hydrologic L-A coupling. This is detectable globally, and happens through the evapotranspiration-precipitation segment. But on seasonal timescales, SP does not exhibit detectable effects on hydrologic L-A coupling. Two robust regional effects of SP on thermal L-A coupling have also been explored. Over the Arabian Peninsula, SP reduces thermal L-A coupling through a straightforward control by mean rainfall reduction. More counterintuitively, over the Southwestern US and Northern Mexico, SP enhances the thermal L-A coupling in a way that is independent of rainfall and soil moisture. This signal is associated with a systematic and previously unrecognized effect of SP that produces an amplified Bowen ratio, and is detectable in multiple SP model versions and experiment designs. In addition to amplifying the present-day Bowen ratio, SP is found to amplify the climate sensitivity of Bowen ratio as well, which likely plays a role in influencing climate change predictions at the L-A interface.

  9. BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure

    PubMed Central

    Becher, Matthias A; Grimm, Volker; Thorbek, Pernille; Horn, Juliane; Kennedy, Peter J; Osborne, Juliet L

    2014-01-01

    A notable increase in failure of managed European honeybee Apis mellifera L. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact. In silico experiments offer a fast and cost-effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics. We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa-transmitted viruses and allows foragers in an agent-based foraging model to collect food from a representation of a spatially explicit landscape. We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested. Synthesis and applications. BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee colony dynamics. PMID:25598549

  10. BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure.

    PubMed

    Becher, Matthias A; Grimm, Volker; Thorbek, Pernille; Horn, Juliane; Kennedy, Peter J; Osborne, Juliet L

    2014-04-01

    A notable increase in failure of managed European honeybee Apis mellifera L. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact. In silico experiments offer a fast and cost-effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics.We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa-transmitted viruses and allows foragers in an agent-based foraging model to collect food from a representation of a spatially explicit landscape.We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested. Synthesis and applications . BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee colony dynamics.

  11. ISMIP6 - initMIP: Greenland ice sheet model initialisation experiments

    NASA Astrophysics Data System (ADS)

    Goelzer, Heiko; Nowicki, Sophie; Payne, Tony; Larour, Eric; Abe Ouchi, Ayako; Gregory, Jonathan; Lipscomb, William; Seroussi, Helene; Shepherd, Andrew; Edwards, Tamsin

    2016-04-01

    Earlier large-scale Greenland ice sheet sea-level projections e.g. those run during ice2sea and SeaRISE initiatives have shown that ice sheet initialisation can have a large effect on the projections and gives rise to important uncertainties. This intercomparison exercise (initMIP) aims at comparing, evaluating and improving the initialization techniques used in the ice sheet modeling community and to estimate the associated uncertainties. It is the first in a series of ice sheet model intercomparison activities within ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6). The experiments are conceived for the large-scale Greenland ice sheet and are designed to allow intercomparison between participating models of 1) the initial present-day state of the ice sheet and 2) the response in two schematic forward experiments. The latter experiments serve to evaluate the initialisation in terms of model drift (forward run without any forcing) and response to a large perturbation (prescribed surface mass balance anomaly). We present and discuss first results of the intercomparison and highlight important uncertainties with respect to projections of the Greenland ice sheet sea-level contribution.

  12. Development of a design model for airfoil leading edge film cooling

    NASA Astrophysics Data System (ADS)

    Wadia, A. R.; Nealy, D. A.

    1985-03-01

    A series of experiments on scaled cylinder models having injection through holes inclined at 20, 30, 45, and 90 degrees are presented. The experiments were conducted in a wind tunnel on several stainless steel test specimens in which flow and heat transfer parameters were measured over simulated airfoil leading edge surfaces. On the basis of the experimental results, an engineering design model is proposed that treats the gas-to-surface heat transfer coefficient with film cooling in a manner suggested by Luckey and L'Ecuyer (1981). It is shown that the main factor influencing the averaged film cooling effectiveness in the showerhead region is the inclination of the injection holes. The effectiveness parameter was not affected by variations in the coolant-to-gas stream pressure ratio, the freestream Mach number, the gas to coolant temperature ratio, or the gas stream Reynolds number. Experience in the wind tunnel tests is reflected in the design of the model in which the coolant side heat transfer coefficient is offset by a simultaneous increase in the gas side film coefficient. The design applications of the analytical model are discussed, with emphasis given to high temperature first stage turbine vanes and rotor blades.

  13. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    The goal of this research was to develop a dynamic model which can predict the effect of humidity swings on activated carbon adsorption beds used to remove trace contaminants from the atmosphere in spacecraft. Specifically, the model was to be incorporated into a computer simulation to predict contaminant concentrations exiting the bed as a function of time after a humidity swing occurs. Predicted breakthrough curves were to be compared to experimentally measured results. In all respects the research was successful. The two major aspects of this research were the mathematical model and the experiments. Experiments were conducted by Mr. Appel using a fixed-bed apparatus at NASA-Ames Research Center during the summers of 1994 and 1995 and during the first 8 months of 1996. Mr. Appel conducted most of his mathematical modeling work at the University of Virginia. The simulation code was used to predict breakthrough curves using adsorption equilibrium correlations developed previously by M. D. LeVan's research group at the University of Virginia. These predictions were compared with the experimental measurements, and this led to improvements in both the simulation code and the apparatus.

  14. Dendritic Immunotherapy Improvement for an Optimal Control Murine Model

    PubMed Central

    Chimal-Eguía, J. C.; Castillo-Montiel, E.

    2017-01-01

    Therapeutic protocols in immunotherapy are usually proposed following the intuition and experience of the therapist. In order to deduce such protocols mathematical modeling, optimal control and simulations are used instead of the therapist's experience. Clinical efficacy of dendritic cell (DC) vaccines to cancer treatment is still unclear, since dendritic cells face several obstacles in the host environment, such as immunosuppression and poor transference to the lymph nodes reducing the vaccine effect. In view of that, we have created a mathematical murine model to measure the effects of dendritic cell injections admitting such obstacles. In addition, the model considers a therapy given by bolus injections of small duration as opposed to a continual dose. Doses timing defines the therapeutic protocols, which in turn are improved to minimize the tumor mass by an optimal control algorithm. We intend to supplement therapist's experience and intuition in the protocol's implementation. Experimental results made on mice infected with melanoma with and without therapy agree with the model. It is shown that the dendritic cells' percentage that manages to reach the lymph nodes has a crucial impact on the therapy outcome. This suggests that efforts in finding better methods to deliver DC vaccines should be pursued. PMID:28912828

  15. Shared or Integrated: Which Type of Integration is More Effective Improves Students’ Creativity?

    NASA Astrophysics Data System (ADS)

    Mariyam, M.; Kaniawati, I.; Sriyati, S.

    2017-09-01

    Integrated science learning has various types of integration. This study aims to apply shared and integrated type of integration with project based learning (PjBL) model to improve students’ creativity on waste recycling theme. The research method used is a quasi experiment with the matching-only pre test-post test design. The samples of this study are 108 students consisting of 36 students (experiment class 1st), 35 students (experiment class 2nd) and 37 students (control class 3rd) at one of Junior High School in Tanggamus, Lampung. The results show that there is difference of creativity improvement in the class applied by PjBL model with shared type of integration, integrated type of integration and without any integration in waste recycling theme. Class applied by PjBL model with shared type of integration has the higher creativity improvement than the PjBL model with integrated type of integration and without any integration. Integrated science learning using shared type only combines 2 lessons, hence an intact concept is resulted. So, PjBL model with shared type of integration more effective improves students’ creativity than integrated type.

  16. Stepwise verification of bone regeneration using recombinant human bone morphogenetic protein-2 in rat fibula model

    PubMed Central

    2017-01-01

    Objectives The purpose of this study was to introduce our three experiments on bone morphogenetic protein (BMP) and its carriers performed using the critical sized segmental defect (CSD) model in rat fibula and to investigate development of animal models and carriers for more effective bone regeneration. Materials and Methods For the experiments, 14, 16, and 24 rats with CSDs on both fibulae were used in Experiments 1, 2, and 3, respectively. BMP-2 with absorbable collagen sponge (ACS) (Experiments 1 and 2), autoclaved autogenous bone (AAB) and fibrin glue (FG) (Experiment 3), and xenogenic bone (Experiment 2) were used in the experimental groups. Radiographic and histomorphological evaluations were performed during the follow-up period of each experiment. Results Significant new bone formation was commonly observed in all experimental groups using BMP-2 compared to control and xenograft (porcine bone) groups. Although there was some difference based on BMP carrier, regenerated bone volume was typically reduced by remodeling after initially forming excessive bone. Conclusion BMP-2 demonstrates excellent ability for bone regeneration because of its osteoinductivity, but efficacy can be significantly different depending on its delivery system. ACS and FG showed relatively good bone regeneration capacity, satisfying the essential conditions of localization and release-control when used as BMP carriers. AAB could not provide release-control as a BMP carrier, but its space-maintenance role was remarkable. Carriers and scaffolds that can provide sufficient support to the BMP/carrier complex are necessary for large bone defects, and AAB is thought to be able to act as an effective scaffold. The CSD model of rat fibula is simple and useful for initial estimate of bone regeneration by agents including BMPs. PMID:29333367

  17. The deformation mechanisms and size effects of single-crystal magnesium

    NASA Astrophysics Data System (ADS)

    Byer, Cynthia M.

    In this work, we seek to understand the deformation mechanisms and size effects of single-crystal magnesium at the micrometer scale through both microcompression experiments and finite element simulations. Microcompression experiments are conducted to investigate the impact of initial dislocation density and orientation on size effects. Micropillars are fabricated using a focused ion beam and tested in a Nanoindenter using a diamond fiat tip as a compression platen. Two different initial dislocation densities are examined for [0001] oriented micropillars. Our results demonstrate that decreasing the initial dislocation density results in an increased size effect in terms of increased strength and stochasticity. Microcompression along the [23¯14] axis results in much lower strengths than for [0001] oriented samples. Post-mortem analysis reveals basal slip in both [0001] and [23¯14] micropillars. The application of a stochastic probability model shows good agreement between theoretical predictions and experimental results for size effects with our values of initial dislocation density and micropillar dimensions. Size effects are then incorporated into a single-crystal plasticity model (modified from Zhang and Joshi [1]) implemented in ABAQUS/STANDARD as a user-material subroutine. The model successfully captures the phenomena typically associated with size effects of increasing stochasticity and strength with decreasing specimen size and also accounts for the changing trends resulting from variations in initial dislocation density that we observe in the experiments. Finally, finite element simulations are performed with the original (traditional, without size effects) crystal plasticity model [1] to investigate the relative activities of the deformation modes of single-crystal magnesium for varying degrees of misalignment in microcompression. The simulations reveal basal activity in all micropillars, even for perfectly aligned compression along the [0001] axis. Pyramidal < c + a > activity dominates until the misalignment increases to 2°, when basal slip takes over as the dominant mode. The stress-strain curves for the case of 0° misalignment agrees well with experimental curves, indicating that good alignment was achieved during the experiments. Through this investigation, we gain a better understanding of how to control the size effects, as well as the deformation mechanisms operating at the small scale in magnesium.

  18. A tridiagonal parsimonious higher order multivariate Markov chain model

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Yang, Chuan-sheng

    2017-09-01

    In this paper, we present a tridiagonal parsimonious higher-order multivariate Markov chain model (TPHOMMCM). Moreover, estimation method of the parameters in TPHOMMCM is give. Numerical experiments illustrate the effectiveness of TPHOMMCM.

  19. Effect of Reflective Practice on Student Recall of Acoustics for Speech Science

    ERIC Educational Resources Information Center

    Walden, Patrick R.; Bell-Berti, Fredericka

    2013-01-01

    Researchers have developed models of learning through experience; however, these models are rarely named as a conceptual frame for educational research in the sciences. This study examined the effect of reflective learning responses on student recall of speech acoustics concepts. Two groups of undergraduate students enrolled in a speech science…

  20. Effects of syntactic structure in the memory of concrete and abstract Chinese sentences.

    PubMed

    Ho, C S; Chen, H C

    1993-09-01

    Smith (1981) found that concrete English sentences were better recognized than abstract sentences and that this concreteness effect was potent only when the concrete sentence was also affirmative but the effect switched to an opposite end when the concrete sentence was negative. These results were partially replicated in Experiment 1 by using materials from a very different language (i.e., Chinese): concrete-affirmative sentences were better remembered than concrete-negative and abstract sentences, but no reliable difference was found between the latter two types. In Experiment 2, the task was modified by using a visual presentation instead of an oral one as in Experiment 1. Both concrete-affirmative and concrete-negative sentences were better memorized then abstract ones in Experiment 2. The findings in the two experiments are explained by a combination of the dual-coding model and Marschark's (1985) item-specific and relational processing. The differential effects of experience with different language systems on processing verbal materials in memory are also discussed.

  1. Representing ductile damage with the dual domain material point method

    DOE PAGES

    Long, C. C.; Zhang, D. Z.; Bronkhorst, C. A.; ...

    2015-12-14

    In this study, we incorporate a ductile damage material model into a computational framework based on the Dual Domain Material Point (DDMP) method. As an example, simulations of a flyer plate experiment involving ductile void growth and material failure are performed. The results are compared with experiments performed on high purity tantalum. We also compare the numerical results obtained from the DDMP method with those obtained from the traditional Material Point Method (MPM). Effects of an overstress model, artificial viscosity, and physical viscosity are investigated. Our results show that a physical bulk viscosity and overstress model are important in thismore » impact and failure problem, while physical shear viscosity and artificial shock viscosity have negligible effects. A simple numerical procedure with guaranteed convergence is introduced to solve for the equilibrium plastic state from the ductile damage model.« less

  2. CFD study on the effects of boundary conditions on air flow through an air-cooled condenser

    NASA Astrophysics Data System (ADS)

    Sumara, Zdeněk; Šochman, Michal

    2018-06-01

    This study focuses on the effects of boundary conditions on effectiveness of an air-cooled condenser (ACC). Heat duty of ACC is very often calculated for ideal uniform velocity field which does not correspond to reality. Therefore, this study studies the effect of wind and different landscapes on air flow through ACC. For this study software OpenFOAM was used and the flow was simulated with the use of RANS equations. For verification of numerical setup a model of one ACC cell with dimensions of platform 1.5×1.5 [m] was used. In this experiment static pressures behind fan and air flows through a model of surface of condenser for different rpm of fan were measured. In OpenFOAM software a virtual clone of this experiment was built and different meshes, turbulent models and numerical schemes were tested. After tuning up numerical setup virtual model of real ACC system was built. Influence of wind, landscape and height of ACC on air flow through ACC has been investigated.

  3. Wind-US Code Contributions to the First AIAA Shock Boundary Layer Interaction Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nicholas J.; Vyas, Manan A.; Yoder, Dennis A.

    2013-01-01

    This report discusses the computations of a set of shock wave/turbulent boundary layer interaction (SWTBLI) test cases using the Wind-US code, as part of the 2010 American Institute of Aeronautics and Astronautics (AIAA) shock/boundary layer interaction workshop. The experiments involve supersonic flows in wind tunnels with a shock generator that directs an oblique shock wave toward the boundary layer along one of the walls of the wind tunnel. The Wind-US calculations utilized structured grid computations performed in Reynolds-averaged Navier-Stokes mode. Four turbulence models were investigated: the Spalart-Allmaras one-equation model, the Menter Baseline and Shear Stress Transport k-omega two-equation models, and an explicit algebraic stress k-omega formulation. Effects of grid resolution and upwinding scheme were also considered. The results from the CFD calculations are compared to particle image velocimetry (PIV) data from the experiments. As expected, turbulence model effects dominated the accuracy of the solutions with upwinding scheme selection indicating minimal effects.

  4. Kinetic model of water disinfection using peracetic acid including synergistic effects.

    PubMed

    Flores, Marina J; Brandi, Rodolfo J; Cassano, Alberto E; Labas, Marisol D

    2016-01-01

    The disinfection efficiencies of a commercial mixture of peracetic acid against Escherichia coli were studied in laboratory scale experiments. The joint and separate action of two disinfectant agents, hydrogen peroxide and peracetic acid, were evaluated in order to observe synergistic effects. A kinetic model for each component of the mixture and for the commercial mixture was proposed. Through simple mathematical equations, the model describes different stages of attack by disinfectants during the inactivation process. Based on the experiments and the kinetic parameters obtained, it could be established that the efficiency of hydrogen peroxide was much lower than that of peracetic acid alone. However, the contribution of hydrogen peroxide was very important in the commercial mixture. It should be noted that this improvement occurred only after peracetic acid had initiated the attack on the cell. This synergistic effect was successfully explained by the proposed scheme and was verified by experimental results. Besides providing a clearer mechanistic understanding of water disinfection, such models may improve our ability to design reactors.

  5. The effectiveness of snow cube throwing learning model based on exploration

    NASA Astrophysics Data System (ADS)

    Sari, Nenden Mutiara

    2017-08-01

    This study aimed to know the effectiveness of Snow Cube Throwing (SCT) and Cooperative Model in Exploration-Based Math Learning in terms of the time required to complete the teaching materials and student engagement. This study was quasi-experimental research was conducted at SMPN 5 Cimahi, Indonesia. All student in grade VIII SMPN 5 Cimahi which consists of 382 students is used as population. The sample consists of two classes which had been chosen randomly with purposive sampling. First experiment class consists of 38 students and the second experiment class consists of 38 students. Observation sheet was used to observe the time required to complete the teaching materials and record the number of students involved in each meeting. The data obtained was analyzed by independent sample-t test and used the chart. The results of this study: SCT learning model based on exploration are more effective than cooperative learning models based on exploration in terms of the time required to complete teaching materials based on exploration and student engagement.

  6. Mean-field model of the von Kármán sodium dynamo experiment using soft iron impellers.

    PubMed

    Nore, C; Léorat, J; Guermond, J-L; Giesecke, A

    2015-01-01

    It has been observed that dynamo action occurs in the von-Kármán-Sodium (VKS) experiment only when the rotating disks and the blades are made of soft iron. The purpose of this paper is to numerically investigate the role of soft iron in the VKS dynamo scenario. This is done by using a mean-field model based on an axisymmetric mean flow, a localized permeability distribution, and a localized α effect modeling the action of the small velocity scales between the blades. The action of the rotating blades is modeled by an axisymmetric effective permeability field. Key properties of the flow giving to the numerical magnetic field a geometric structure similar to that observed experimentally are identified. Depending on the permeability of the disks and the effective permeability of the blades, the dynamo that is obtained is either oscillatory or stationary. Our numerical results confirm the leading role played by the ferromagnetic impellers. A scenario for the VKS dynamo is proposed.

  7. Grounded Learning Experience: Helping Students Learn Physics through Visuo-Haptic Priming and Instruction

    ERIC Educational Resources Information Center

    Huang, Shih-Chieh Douglas

    2013-01-01

    In this dissertation, I investigate the effects of a grounded learning experience on college students' mental models of physics systems. The grounded learning experience consisted of a priming stage and an instruction stage, and within each stage, one of two different types of visuo-haptic representation was applied: visuo-gestural simulation…

  8. Change Management Model for Implementing an Effective First-Year Experience Program in the Community College Setting

    ERIC Educational Resources Information Center

    Tucker, Joy C.

    2015-01-01

    This study provides evidence that systematic management of change can facilitate the implementation of first-year experience programming that leads to improved results in retention and student success for community college students. The study includes four major themes: (a) first-year experience, (b) change management, (c) change leadership, and…

  9. Knowledge and the Experience of Women Living Underground during the Portuguese Dictatorship

    ERIC Educational Resources Information Center

    Nogueira, Cristina Marques

    2015-01-01

    This paper assumes that formative processes are not limited to the school context or model but that other life contexts and experiences, even if not intentionally, have educational effects. These informal formative contexts and experiences can play a key role individual´s development, resulting not only in superficial changes, but also in deep…

  10. Analysis of the moisture diffusion transfer through fibrous porous membrane used for waterproof breathable fabrics

    NASA Astrophysics Data System (ADS)

    Zhu, Fanglong; Zhou, Yu; Liu, Suyan

    2013-10-01

    In this paper, we propose a new fractal model to determine the moisture effective diffusivity of porous membrane such as expanded polytetrafluorethylene membrane, by taking account of both parallel and perpendicular channels to diffusion flow direction. With the consideration of both the Knudsen and bulk diffusion effect, a relationship between micro-structural parameters and effective moisture diffusivity is deduced. The effective moisture diffusivities predicted by the present fractal model are compared with moisture diffusion experiment data and calculated values obtained from other theoretical models.

  11. The empathy impulse: A multinomial model of intentional and unintentional empathy for pain.

    PubMed

    Cameron, C Daryl; Spring, Victoria L; Todd, Andrew R

    2017-04-01

    Empathy for pain is often described as automatic. Here, we used implicit measurement and multinomial modeling to formally quantify unintentional empathy for pain: empathy that occurs despite intentions to the contrary. We developed the pain identification task (PIT), a sequential priming task wherein participants judge the painfulness of target experiences while trying to avoid the influence of prime experiences. Using multinomial modeling, we distinguished 3 component processes underlying PIT performance: empathy toward target stimuli (Intentional Empathy), empathy toward prime stimuli (Unintentional Empathy), and bias to judge target stimuli as painful (Response Bias). In Experiment 1, imposing a fast (vs. slow) response deadline uniquely reduced Intentional Empathy. In Experiment 2, inducing imagine-self (vs. imagine-other) perspective-taking uniquely increased Unintentional Empathy. In Experiment 3, Intentional and Unintentional Empathy were stronger toward targets with typical (vs. atypical) pain outcomes, suggesting that outcome information matters and that effects on the PIT are not reducible to affective priming. Typicality of pain outcomes more weakly affected task performance when target stimuli were merely categorized rather than judged for painfulness, suggesting that effects on the latter are not reducible to semantic priming. In Experiment 4, Unintentional Empathy was stronger for participants who engaged in costly donation to cancer charities, but this parameter was also high for those who donated to an objectively worse but socially more popular charity, suggesting that overly high empathy may facilitate maladaptive altruism. Theoretical and practical applications of our modeling approach for understanding variation in empathy are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. Student experience of hub and spoke model of placement allocation - An evaluative study.

    PubMed

    Thomas, Megan; Westwood, Nicky

    2016-11-01

    An evaluative project was undertaken at the University of Wolverhampton centring on the Hub and Spoke model utilised for organisation of placement allocation across the BNurs programme for all fields of nursing. Student experience was of particular interest throughout the evaluation with the research team focusing on the views, feelings and experiences of student nurses in relation to the hub and spoke model applied for practice. A qualitative approach was adopted, initially using Survey Monkey to collect student views through a series of open questions, and further enhanced by focus groups. These were transcribed and together with the data from the surveys, data was categorized and themed. Themes were analysed and conclusions drawn. The hub and spoke method for placements was found to enhance student understanding of the whole patient journey which offered students a wide breadth of experience and development of transferable skills such as communication and adaptability. A sense of increased belonging was highlighted by students which encouraged the development of strong effective relationships positively affecting their learning. Some less positive aspects were apparent revolving around personality difficulties and organisational problems, in particular relating to spoke placements. The purpose of spoke placements was not always apparent and sometimes there was a lack of appropriate student placement experiences provided by spoke mentors. Overall the hub and spoke model for organising placement was found to be beneficial and enhanced the student's experience, satisfaction and learning, which in turn had a positive effect on practice. Copyright © 2016. Published by Elsevier Ltd.

  13. Thin Images Reflected in the Water: Narcissism and Girls' Vulnerability to the Thin-Ideal.

    PubMed

    Thomaes, Sander; Sedikides, Constantine

    2016-10-01

    The purpose of this research is to test how adolescent girls' narcissistic traits-characterized by a need to impress others and avoid ego-threat-influence acute adverse effects of thin-ideal exposure. Participants (11-15 years; total N = 366; all female) reported their narcissistic traits. Next, in two experiments, they viewed images of either very thin or average-sized models, reported their wishful identification with the models (Experiment 2), and tasted high-calorie foods in an alleged taste test (both experiments). Narcissism kept girls from wishfully identifying with thin models, which is consistent with the view that narcissistic girls are prone to disengage from thin-ideal exposure. Moreover, narcissism protected vulnerable girls (those who experience low weight-esteem) from inhibiting their food intake, and led other girls (those who consider their appearance relatively unimportant) to increase their food intake. These effects did not generalize to conceptually related traits of self-esteem and perfectionism, and were not found for a low-calorie foods outcome, attesting to the specificity of findings. These experiments demonstrate the importance of narcissism at reducing girls' thin-ideal vulnerability. Girls high in narcissism disengage self-protectively from threats to their self-image, a strategy that renders at least subsets of them less vulnerable to the thin-ideal. © 2015 Wiley Periodicals, Inc.

  14. User-experience surveys with maternity services: a randomized comparison of two data collection models.

    PubMed

    Bjertnaes, Oyvind Andresen; Iversen, Hilde Hestad

    2012-08-01

    To compare two ways of combining postal and electronic data collection for a maternity services user-experience survey. Cross-sectional survey. Maternity services in Norway. All women who gave birth at a university hospital in Norway between 1 June and 27 July 2010. Patients were randomized into the following groups (n= 752): Group A, who were posted questionnaires with both electronic and paper response options for both the initial and reminder postal requests; and Group B, who were posted questionnaires with an electronic response option for the initial request, and both electronic and paper response options for the reminder postal request. Response rate, the amount of difference in background variables between respondents and non-respondents, main study results and estimated cost-effectiveness. The final response rate was significantly higher in Group A (51.9%) than Group B (41.1%). None of the background variables differed significantly between the respondents and non-respondents in Group A, while two variables differed significantly between the respondents and non-respondents in Group B. None of the 11 user-experience scales differed significantly between Groups A and B. The estimated costs per response for the forthcoming national survey was €11.7 for data collection Model A and €9.0 for Model B. The model with electronic-only response option in the first request had lowest response rate. However, this model performed equal to the other model on non-response bias and better on estimated cost-effectiveness, and is the better of the two models in large-scale user experiences surveys with maternity services.

  15. Aging and the rate of visual information processing.

    PubMed

    Guest, Duncan; Howard, Christina J; Brown, Louise A; Gleeson, Harriet

    2015-01-01

    Multiple methods exist for measuring how age influences the rate of visual information processing. The most advanced methods model the processing dynamics in a task in order to estimate processing rates independently of other factors that might be influenced by age, such as overall performance level and the time at which processing onsets. However, such modeling techniques have produced mixed evidence for age effects. Using a time-accuracy function (TAF) analysis, Kliegl, Mayr, and Krampe (1994) showed clear evidence for age effects on processing rate. In contrast, using the diffusion model to examine the dynamics of decision processes, Ratcliff and colleagues (e.g., Ratcliff, Thapar, & McKoon, 2006) found no evidence for age effects on processing rate across a range of tasks. Examination of these studies suggests that the number of display stimuli might account for the different findings. In three experiments we measured the precision of younger and older adults' representations of target stimuli after different amounts of stimulus exposure. A TAF analysis found little evidence for age differences in processing rate when a single stimulus was presented (Experiment 1). However, adding three nontargets to the display resulted in age-related slowing of processing (Experiment 2). Similar slowing was observed when simply presenting two stimuli and using a post-cue to indicate the target (Experiment 3). Although there was some interference from distracting objects and from previous responses, these age-related effects on processing rate seem to reflect an age-related difficulty in processing multiple objects, particularly when encoding them into visual working memory.

  16. The picture superiority effect: support for the distinctiveness model.

    PubMed

    Mintzer, M Z; Snodgrass, J G

    1999-01-01

    The form change paradigm was used to explore the basis for the picture superiority effect. Recognition memory for studied pictures and words was tested in their study form or the alternate form. Form change cost was defined as the difference between recognition performance for same and different form items. Based on the results of Experiment 1 and previous studies, it was difficult to determine the relative cost for studied pictures and words due to a reversal of the mirror effect. We hypothesized that the reversed mirror effect results from subjects' basing their recognition decisions on their assumptions about the study form. Experiments 2 and 3 confirmed this hypothesis and generated a method for evaluating the relative cost for pictures and words despite the reversed mirror effect. More cost was observed for pictures than words, supporting the distinctiveness model of the picture superiority effect.

  17. Integrating Multiscale Modeling with Drug Effects for Cancer Treatment.

    PubMed

    Li, Xiangfang L; Oduola, Wasiu O; Qian, Lijun; Dougherty, Edward R

    2015-01-01

    In this paper, we review multiscale modeling for cancer treatment with the incorporation of drug effects from an applied system's pharmacology perspective. Both the classical pharmacology and systems biology are inherently quantitative; however, systems biology focuses more on networks and multi factorial controls over biological processes rather than on drugs and targets in isolation, whereas systems pharmacology has a strong focus on studying drugs with regard to the pharmacokinetic (PK) and pharmacodynamic (PD) relations accompanying drug interactions with multiscale physiology as well as the prediction of dosage-exposure responses and economic potentials of drugs. Thus, it requires multiscale methods to address the need for integrating models from the molecular levels to the cellular, tissue, and organism levels. It is a common belief that tumorigenesis and tumor growth can be best understood and tackled by employing and integrating a multifaceted approach that includes in vivo and in vitro experiments, in silico models, multiscale tumor modeling, continuous/discrete modeling, agent-based modeling, and multiscale modeling with PK/PD drug effect inputs. We provide an example application of multiscale modeling employing stochastic hybrid system for a colon cancer cell line HCT-116 with the application of Lapatinib drug. It is observed that the simulation results are similar to those observed from the setup of the wet-lab experiments at the Translational Genomics Research Institute.

  18. Evaluating the effectiveness of intercultural teachers.

    PubMed

    Cox, Kathleen

    2011-01-01

    With globalization and major immigration flows, intercultural teaching encounters are likely to increase, along with the need to assure intercultural teaching effectiveness.Thus, the purpose of this article is to present a conceptual framework for nurse educators to consider when anticipating an intercultural teaching experience. Kirkpatrick's and Bushnell's models provide a basis for the conceptual framework. Major concepts of the model include input, process, output, and outcome.The model may possibly be used to guide future research to determine which variables are most influential in explaining intercultural teaching effectiveness.

  19. Fatigue Debonding of the Roughened Stem–Cement Interface: Effects of Surface Roughness and Stem Heating Conditions

    PubMed Central

    Damron, Leatha A.; Kim, Do-Gyoon; Mann, Kenneth A.

    2007-01-01

    The aim of this study was to determine the effects of cyclic loading on the debond process of a roughened stem– cement interface used in total hip arthroplasty. The specific goals were to assess the effects of two surgeon-controlled variables (stem heating and degree of stem surface roughness) and to determine if an independent finite element-based fracture mechanics model could be used to predict the debond response. A clamped cantilever beam geometry was used to determine the fatigue debond response of the stem– cement interface and was created using an experimental mold that simulated in vivo cementing conditions. A second experiment was performed using a torsion-loading model representative of the stem– cement–bone composite. For both experiments, two stem heating (room temperature and 50°C) and surface roughness conditions (grit blasted: Ra = 2.3 and 5.1 μm) were used. Finally, a finite element model of the torsion experiment with provision for crack growth was developed and compared with the experimental results. Results from both experiments revealed that neither stem preheating nor use of a stem with a greater surface roughness had a marked effect on the fatigue debond response. There was substantial variability in the debond response for all cases; this may be due to microscopic gaps at the interface for all interface conditions. The debond rate from the finite element simulation (10−7.31 m/cycle) had a magnitude similar to the experimental torsion model (10− (6.77 ± 1.25) m/cycle). This suggests that within the context of the experimental conditions studied here that the debond response could be assessed using a linear elastic fracture mechanics-type approach. PMID:16292769

  20. Short-Term Memory for Temporal Intervals: Contrasting Explanations of the Choose-Short Effect in Pigeons

    ERIC Educational Resources Information Center

    Pinto, Carlos; Machado, Armando

    2011-01-01

    To better understand short-term memory for temporal intervals, we re-examined the choose-short effect. In Experiment 1, to contrast the predictions of two models of this effect, the subjective shortening and the coding models, pigeons were exposed to a delayed matching-to-sample task with three sample durations (2, 6 and 18 s) and retention…

  1. Comparisons of CTH simulations with measured wave profiles for simple flyer plate experiments

    DOE PAGES

    Thomas, S. A.; Veeser, L. R.; Turley, W. D.; ...

    2016-06-13

    We conducted detailed 2-dimensional hydrodynamics calculations to assess the quality of simulations commonly used to design and analyze simple shock compression experiments. Such simple shock experiments also contain data where dynamic properties of materials are integrated together. We wished to assess how well the chosen computer hydrodynamic code could do at capturing both the simple parts of the experiments and the integral parts. We began with very simple shock experiments, in which we examined the effects of the equation of state and the compressional and tensile strength models. We increased complexity to include spallation in copper and iron and amore » solid-solid phase transformation in iron to assess the quality of the damage and phase transformation simulations. For experiments with a window, the response of both the sample and the window are integrated together, providing a good test of the material models. While CTH physics models are not perfect and do not reproduce all experimental details well, we find the models are useful; the simulations are adequate for understanding much of the dynamic process and for planning experiments. However, higher complexity in the simulations, such as adding in spall, led to greater differences between simulation and experiment. Lastly, this comparison of simulation to experiment may help guide future development of hydrodynamics codes so that they better capture the underlying physics.« less

  2. Evaluation and linking of effective parameters in particle-based models and continuum models for mixing-limited bimolecular reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Papelis, Charalambos; Sun, Pengtao; Yu, Zhongbo

    2013-08-01

    Particle-based models and continuum models have been developed to quantify mixing-limited bimolecular reactions for decades. Effective model parameters control reaction kinetics, but the relationship between the particle-based model parameter (such as the interaction radius R) and the continuum model parameter (i.e., the effective rate coefficient Kf) remains obscure. This study attempts to evaluate and link R and Kf for the second-order bimolecular reaction in both the bulk and the sharp-concentration-gradient (SCG) systems. First, in the bulk system, the agent-based method reveals that R remains constant for irreversible reactions and decreases nonlinearly in time for a reversible reaction, while mathematical analysis shows that Kf transitions from an exponential to a power-law function. Qualitative link between R and Kf can then be built for the irreversible reaction with equal initial reactant concentrations. Second, in the SCG system with a reaction interface, numerical experiments show that when R and Kf decline as t-1/2 (for example, to account for the reactant front expansion), the two models capture the transient power-law growth of product mass, and their effective parameters have the same functional form. Finally, revisiting of laboratory experiments further shows that the best fit factor in R and Kf is on the same order, and both models can efficiently describe chemical kinetics observed in the SCG system. Effective model parameters used to describe reaction kinetics therefore may be linked directly, where the exact linkage may depend on the chemical and physical properties of the system.

  3. Effect of spine motion on mobility in quadruped running

    NASA Astrophysics Data System (ADS)

    Chen, Dongliang; Liu, Qi; Dong, Litao; Wang, Hong; Zhang, Qun

    2014-11-01

    Most of current running quadruped robots have similar construction: a stiff body and four compliant legs. Many researches have indicated that the stiff body without spine motion is a main factor in limitation of robots' mobility. Therefore, investigating spine motion is very important to build robots with better mobility. A planar quadruped robot is designed based on cheetahs' morphology. There is a spinal driving joint in the body of the robot. When the spinal driving joint acts, the robot has spine motion; otherwise, the robot has not spine motion. Six group prototype experiments with the robot are carried out to study the effect of spine motion on mobility. In each group, there are two comparative experiments: the spinal driving joint acts in one experiment but does not in the other experiment. The results of the prototype experiments indicate that the average speeds of the robot with spine motion are 8.7%-15.9% larger than those of the robot without spine motion. Furthermore, a simplified sagittal plane model of quadruped mammals is introduced. The simplified model also has a spinal driving joint. Using a similar process as the prototype experiments, six group simulation experiments with the simplified model are conducted. The results of the simulation experiments show that the maximum rear leg horizontal thrusts of the simplified mode with spine motion are 68.2%-71.3% larger than those of the simplified mode without spine motion. Hence, it is found that spine motion can increase the average running speed and the intrinsic reason of speed increase is the improvement of the maximum rear leg horizontal thrust.

  4. Tracer adsorption in sand-tank experiments of saltwater up-coning

    NASA Astrophysics Data System (ADS)

    Jakovovic, Danica; Post, Vincent E. A.; Werner, Adrian D.; Männicke, Oliver; Hutson, John L.; Simmons, Craig T.

    2012-01-01

    SummaryThis study aims to substantiate otherwise unresolved double-peaked plumes produced in recent saltwater up-coning experiments (see Jakovovic et al. (2011), Numerical modelling of saltwater up-coning: Comparison with experimental laboratory observations, Journal of Hydrology 402, 261-273) through additional laboratory testing and numerical modelling. Laboratory experimentation successfully reproduced the double-peaked plume demonstrating that this phenomenon was not an experimental nuance in previous experiments. Numerical modelling by Jakovovic et al. (2011) was extended by considering adsorption effects, which were needed to explain the observed up-coning double peaks of both previous and current laboratory experiments. A linear adsorption isotherm was applied in predicting dye tracer (Rhodamine WT) behaviour in the sand-tank experiments using adsorption parameters obtained experimentally. The same adsorption parameters were tested on all laboratory experiments and it was found that adsorption had insignificant effect on experiments with high pumping rates. However, low pumping rates produced pronounced spatial velocity variations within the dense salt plume beneath the pumping well, with velocities within the plume increasing from the centre of the plume towards the interface. The dye tracer was retarded relative to the salt and was transported preferentially along the higher-velocity paths (i.e. along the edges of the salt plume) towards the well forming double-peaked up-coning patterns. This illustrates the sensitive adsorptive nature of Rhodamine WT and that care should be taken when it is used in similar sand-tank experiments. Observations from this study offer insight into the separation of chemicals in natural systems due to different adsorption characteristics and under conditions of density-dependent flow.

  5. [The modeling of the ricochet shot fired from a light weapon].

    PubMed

    Gusentsov, A O; Chuchko, V A; Kil'dyushev, E M; Tumanov, E V

    The objective of the present study was to choose the optimal method for the modeling of the glance of a bullet after hitting a target under conditions of the laboratory experiment. The study required the designing and construction of an original device for the modeling of the rebound effect of a light-firearm shot under experimental conditions. The device was tested under conditions of the laboratory experiment. The trials have demonstrated the possibility of using barriers of different weight and dimensions in the above device, their positioning and fixation depending on the purpose of the experiment, dynamic alteration of its conditions with due regard for the safety and security arrangements to protect the health and life of the experimenters without compromising the statistical significance and scientific validity of the results of the experiments.

  6. Auditory word recognition: extrinsic and intrinsic effects of word frequency.

    PubMed

    Connine, C M; Titone, D; Wang, J

    1993-01-01

    Two experiments investigated the influence of word frequency in a phoneme identification task. Speech voicing continua were constructed so that one endpoint was a high-frequency word and the other endpoint was a low-frequency word (e.g., best-pest). Experiment 1 demonstrated that ambiguous tokens were labeled such that a high-frequency word was formed (intrinsic frequency effect). Experiment 2 manipulated the frequency composition of the list (extrinsic frequency effect). A high-frequency list bias produced an exaggerated influence of frequency; a low-frequency list bias showed a reverse frequency effect. Reaction time effects were discussed in terms of activation and postaccess decision models of frequency coding. The results support a late use of frequency in auditory word recognition.

  7. Orthographic similarity: the case of "reversed anagrams".

    PubMed

    Morris, Alison L; Still, Mary L

    2012-07-01

    How orthographically similar are words such as paws and swap, flow and wolf, or live and evil? According to the letter position coding schemes used in models of visual word recognition, these reversed anagrams are considered to be less similar than words that share letters in the same absolute or relative positions (such as home and hose or plan and lane). Therefore, reversed anagrams should not produce the standard orthographic similarity effects found using substitution neighbors (e.g., home, hose). Simulations using the spatial coding model (Davis, Psychological Review 117, 713-758, 2010), for example, predict an inhibitory masked-priming effect for substitution neighbor word pairs but a null effect for reversed anagrams. Nevertheless, we obtained significant inhibitory priming using both stimulus types (Experiment 1). We also demonstrated that robust repetition blindness can be obtained for reversed anagrams (Experiment 2). Reversed anagrams therefore provide a new test for models of visual word recognition and orthographic similarity.

  8. Does Cation Size Affect Occupancy and Electrostatic Screening of the Nucleic Acid Ion Atmosphere?

    PubMed Central

    2016-01-01

    Electrostatics are central to all aspects of nucleic acid behavior, including their folding, condensation, and binding to other molecules, and the energetics of these processes are profoundly influenced by the ion atmosphere that surrounds nucleic acids. Given the highly complex and dynamic nature of the ion atmosphere, understanding its properties and effects will require synergy between computational modeling and experiment. Prior computational models and experiments suggest that cation occupancy in the ion atmosphere depends on the size of the cation. However, the computational models have not been independently tested, and the experimentally observed effects were small. Here, we evaluate a computational model of ion size effects by experimentally testing a blind prediction made from that model, and we present additional experimental results that extend our understanding of the ion atmosphere. Giambasu et al. developed and implemented a three-dimensional reference interaction site (3D-RISM) model for monovalent cations surrounding DNA and RNA helices, and this model predicts that Na+ would outcompete Cs+ by 1.8–2.1-fold; i.e., with Cs+ in 2-fold excess of Na+ the ion atmosphere would contain an equal number of each cation (Nucleic Acids Res.2015, 43, 8405). However, our ion counting experiments indicate that there is no significant preference for Na+ over Cs+. There is an ∼25% preferential occupancy of Li+ over larger cations in the ion atmosphere but, counter to general expectations from existing models, no size dependence for the other alkali metal ions. Further, we followed the folding of the P4–P6 RNA and showed that differences in folding with different alkali metal ions observed at high concentration arise from cation–anion interactions and not cation size effects. Overall, our results provide a critical test of a computational prediction, fundamental information about ion atmosphere properties, and parameters that will aid in the development of next-generation nucleic acid computational models. PMID:27479701

  9. Modeling Fan Effects on the Time Course of Associative Recognition

    PubMed Central

    Schneider, Darryl W.; Anderson, John R.

    2011-01-01

    We investigated the time course of associative recognition using the response signal procedure, whereby a stimulus is presented and followed after a variable lag by a signal indicating that an immediate response is required. More specifically, we examined the effects of associative fan (the number of associations that an item has with other items in memory) on speed–accuracy tradeoff functions obtained in a previous response signal experiment involving briefly studied materials and in a new experiment involving well-learned materials. High fan lowered asymptotic accuracy or the rate of rise in accuracy across lags, or both. We developed an Adaptive Control of Thought–Rational (ACT-R) model for the response signal procedure to explain these effects. The model assumes that high fan results in weak associative activation that slows memory retrieval, thereby decreasing the probability that retrieval finishes in time and producing a speed–accuracy tradeoff function. The ACT-R model provided an excellent account of the data, yielding quantitative fits that were as good as those of the best descriptive model for response signal data. PMID:22197797

  10. Modeling the effects of contrast enhancement on target acquisition performance

    NASA Astrophysics Data System (ADS)

    Du Bosq, Todd W.; Fanning, Jonathan D.

    2008-04-01

    Contrast enhancement and dynamic range compression are currently being used to improve the performance of infrared imagers by increasing the contrast between the target and the scene content, by better utilizing the available gray levels either globally or locally. This paper assesses the range-performance effects of various contrast enhancement algorithms for target identification with well contrasted vehicles. Human perception experiments were performed to determine field performance using contrast enhancement on the U.S. Army RDECOM CERDEC NVESD standard military eight target set using an un-cooled LWIR camera. The experiments compare the identification performance of observers viewing linearly scaled images and various contrast enhancement processed images. Contrast enhancement is modeled in the US Army thermal target acquisition model (NVThermIP) by changing the scene contrast temperature. The model predicts improved performance based on any improved target contrast, regardless of feature saturation or enhancement. To account for the equivalent blur associated with each contrast enhancement algorithm, an additional effective MTF was calculated and added to the model. The measured results are compared with the predicted performance based on the target task difficulty metric used in NVThermIP.

  11. Modeling the depth-sectioning effect in reflection-mode dynamic speckle-field interferometric microscopy

    PubMed Central

    Zhou, Renjie; Jin, Di; Hosseini, Poorya; Singh, Vijay Raj; Kim, Yang-hyo; Kuang, Cuifang; Dasari, Ramachandra R.; Yaqoob, Zahid; So, Peter T. C.

    2017-01-01

    Unlike most optical coherence microscopy (OCM) systems, dynamic speckle-field interferometric microscopy (DSIM) achieves depth sectioning through the spatial-coherence gating effect. Under high numerical aperture (NA) speckle-field illumination, our previous experiments have demonstrated less than 1 μm depth resolution in reflection-mode DSIM, while doubling the diffraction limited resolution as under structured illumination. However, there has not been a physical model to rigorously describe the speckle imaging process, in particular explaining the sectioning effect under high illumination and imaging NA settings in DSIM. In this paper, we develop such a model based on the diffraction tomography theory and the speckle statistics. Using this model, we calculate the system response function, which is used to further obtain the depth resolution limit in reflection-mode DSIM. Theoretically calculated depth resolution limit is in an excellent agreement with experiment results. We envision that our physical model will not only help in understanding the imaging process in DSIM, but also enable better designing such systems for depth-resolved measurements in biological cells and tissues. PMID:28085800

  12. Dynamical systems characterization of inertial effects of fluid flow in a curved artery model under pulsatile flow forcing

    NASA Astrophysics Data System (ADS)

    Leggiero, Michael; Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    The main objective of this study was to examine inertial effects in a 180-degree model of curved arteries under pulsatile inflow conditions. Two-component, two-dimensional particle image velocimetery (2C-2D PIV) data were acquired upstream of and at several cross-sectional locations in the curved artery model. A blood-analog fluid comprised of 71% saturated sodium iodide solution, 28% glycerol and 1% distilled water (by volume) was subjected to multi-harmonic pulsatile inflow functions. First, signal time-lag was quantified by cross-correlating the input (voltage-time) supplied to a programmable pump and the output PIV (flow rate-time) measurements. The experiment was then treated as a linear, time-invariant system, and frequency response was estimated for phase shifts across a certain spectrum. Input-output signal dissimilarities were attributable to intrinsic inertial effects of flow. By coupling pressure-time and upstream flow rate-time measurements, the experiment was modeled using system identification methods. Results elucidate the role of inertial effects in fluid flow velocity measurements and the effect of these delays on secondary flow structure detection in a curved artery model. Supported by the NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  13. Zero-gravity aerosol behavior

    NASA Technical Reports Server (NTRS)

    Edwards, H. W.

    1981-01-01

    The feasibility and scientific benefits of a zero gravity aerosol study in an orbiting laboratory were examined. A macroscopic model was devised to deal with the simultaneous effects of diffusion and coagulation of particles in the confined aerosol. An analytical solution was found by treating the particle coagulation and diffusion constants as ensemble parameters and employing a transformation of variables. The solution was used to carry out simulated zero gravity aerosol decay experiments in a compact cylindrical chamber. The results demonstrate that the limitations of physical space and time imposed by the orbital situation are not prohibitive in terms of observing the history of an aerosol confined under zero gravity conditions. While the absence of convective effects would be a definite benefit for the experiment, the mathematical complexity of the problem is not greatly reduced when the gravitational term drops out of the equation. Since the model does not deal directly with the evolution of the particle size distribution, it may be desirable to develop more detailed models before undertaking an orbital experiment.

  14. Calculation of Debye-Scherrer diffraction patterns from highly stressed polycrystalline materials

    DOE PAGES

    MacDonald, M. J.; Vorberger, J.; Gamboa, E. J.; ...

    2016-06-07

    Calculations of Debye-Scherrer diffraction patterns from polycrystalline materials have typically been done in the limit of small deviatoric stresses. Although these methods are well suited for experiments conducted near hydrostatic conditions, more robust models are required to diagnose the large strain anisotropies present in dynamic compression experiments. A method to predict Debye-Scherrer diffraction patterns for arbitrary strains has been presented in the Voigt (iso-strain) limit. Here, we present a method to calculate Debye-Scherrer diffraction patterns from highly stressed polycrystalline samples in the Reuss (iso-stress) limit. This analysis uses elastic constants to calculate lattice strains for all initial crystallite orientations, enablingmore » elastic anisotropy and sample texture effects to be modeled directly. Furthermore, the effects of probing geometry, deviatoric stresses, and sample texture are demonstrated and compared to Voigt limit predictions. An example of shock-compressed polycrystalline diamond is presented to illustrate how this model can be applied and demonstrates the importance of including material strength when interpreting diffraction in dynamic compression experiments.« less

  15. Extension of nanoconfined DNA: Quantitative comparison between experiment and theory

    NASA Astrophysics Data System (ADS)

    Iarko, V.; Werner, E.; Nyberg, L. K.; Müller, V.; Fritzsche, J.; Ambjörnsson, T.; Beech, J. P.; Tegenfeldt, J. O.; Mehlig, K.; Westerlund, F.; Mehlig, B.

    2015-12-01

    The extension of DNA confined to nanochannels has been studied intensively and in detail. However, quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose, we performed experiments measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic strength of the buffer. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths, the agreement is less good. We discuss possible reasons. In principle, our approach allows us to measure the Kuhn length and the effective width of a single DNA molecule and more generally of semiflexible polymers in solution.

  16. Implications of drying temperature and humidity on the drying kinetics of seaweed

    NASA Astrophysics Data System (ADS)

    Ali, Majid Khan Majahar; Fudholi, Ahmad; Muthuvalu, M. S.; Sulaiman, Jumat; Yasir, Suhaimi Md

    2017-11-01

    A Low Temperature and Humidity Chamber Test tested in the Solar Energy Laboratory, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia. Experiments are attempted to study the effect of drying air temperature and humidity on the drying kinetics of seaweed Kappaphycus species Striatum besides to develop a model to estimate the drying curves. Simple method using a excel software is used in the analysis of raw data obtained from the drying experiment. The values of the parameters a, n and the constant k for the models are determined using a plot of curve drying models. Three different drying models are compared with experiment data seaweed drying at 30, 40, 50 and 60°C and relative humidity 20, 30 and 40% for seaweed. The higher drying temperatures and low relative humidity effects the moisture content that will be rapidly reduced. The most suitable model is selected to best describe the drying behavior of seaweed. The values of the coefficient of determination (R2), mean bias error (MBE) and root mean square error (RMSE) are used to determine the goodness or the quality of the fit. The Page model is showed a better fit to drying seaweed. The results from this study crucial for solar dryer development on pilot scale in Malaysia.

  17. Fluid dynamic mechanisms and interactions within separated flows and their effects on missile aerodynamics

    NASA Astrophysics Data System (ADS)

    Addy, A. L.; Chow, W. L.; Korst, H. H.; White, R. A.

    1983-05-01

    Significant data and detailed results of a joint research effort investigating the fluid dynamic mechanisms and interactions within separated flows are presented. The results were obtained through analytical, experimental, and computational investigations of base flow related configurations. The research objectives focus on understanding the component mechanisms and interactions which establish and maintain separated flow regions. Flow models and theoretical analyses were developed to describe the base flowfield. The research approach has been to conduct extensive small-scale experiments on base flow configurations and to analyze these flows by component models and finite-difference techniques. The modeling of base flows of missiles (both powered and unpowered) for transonic and supersonic freestreams has been successful by component models. Research on plume effects and plume modeling indicated the need to match initial plume slope and plume surface curvature for valid wind tunnel simulation of an actual rocket plume. The assembly and development of a state-of-the-art laser Doppler velocimeter (LDV) system for experiments with two-dimensional small-scale models has been completed and detailed velocity and turbulence measurements are underway. The LDV experiments include the entire range of base flowfield mechanisms - shear layer development, recompression/reattachment, shock-induced separation, and plume-induced separation.

  18. Presentation-order effects for aesthetic stimulus preference.

    PubMed

    Englund, Mats P; Hellström, Åke

    2012-10-01

    For preference comparisons of paired successive musical excerpts, Koh (American Journal of Psychology, 80, 171-185, 1967) found time-order effects (TOEs) that correlated negatively with stimulus valence-the first (vs. the second) of two unpleasant (vs. two pleasant) excerpts tended to be preferred. We present three experiments designed to investigate whether valence-level-dependent order effects for aesthetic preference (a) can be accounted for using Hellström's (e.g., Journal of Experimental Psychology: Human Perception and Performance, 5, 460-477, 1979) sensation-weighting (SW) model, (b) can be generalized to successive and to simultaneous visual stimuli, and (c) vary, in accordance with the stimulus weighting, with interstimulus interval (ISI; for successive stimuli) or stimulus duration (for simultaneous stimuli). Participants compared paired successive jingles (Exp. 1), successive color patterns (Exp. 2), and simultaneous color patterns (Exp. 3), selecting the preferred stimulus. The results were well described by the SW model, which provided a better fit than did two extended versions of the Bradley-Terry-Luce model. Experiments 1 and 2 revealed higher weights for the second stimulus than for the first, and negatively valence-level-dependent TOEs. In Experiment 3, there was no laterality effect on the stimulus weighting and no valence-level-dependent space-order effects (SOEs). In terms of the SW model, the valence-level-dependent TOEs can be explained as a consequence of differential stimulus weighting in combination with stimulus valence varying from low to high, and the absence of valence-level-dependent SOEs as a consequence of the absence of differential weighting. For successive stimuli, there were no important effects of ISI on weightings and TOEs, and, for simultaneous stimuli, duration had only a small effect on the weighting.

  19. Climatic effects of large-scale deforestation in Earth System Models

    NASA Astrophysics Data System (ADS)

    Brovkin, V.; Boysen, L.; Pongratz, J.

    2017-12-01

    Processes in terrestrial ecosystems, to a large extent, are controlled by climate and CO2 concentration. In turn, geographical distribution of vegetation cover strongly affects heat, moisture, and momentum fluxes between land surface and atmosphere (biogeophysical effects). Anthropogenic land use and land cover changes (LULCC) are now included into Earth System Models (ESMs) in the form of historical and hypothetical future scenarios as a forcing in the Coupled Model Intercomparison project, phase 6 (CMIP6). A propagation of climatic effects from land to the ocean in ESMs allows to investigate a global climate response to LULCC in addition to analysis of local effects over deforested land. One complication in the analysis of global climatic effects of historical and future LULCC scenarios is their relatively small amplitude. To increase the signal-to-noise ratio, the Land Use Model Intercomparison Project (LUMIP) suggested an idealized deforestation simulation following a prototype of 1%-CO2 increase experiment commonly used in CMIPs. The idealized experiment allows to investigate - in a harmonized way across models - a response of land surface biophysics and climate to a large-scale deforestation of 20 million km2 distributed over the most forested parts of globe. The forest is removed linearly over a period of 50 years, with an additional 30 years with no specified change in forest cover. Boundary conditions such as CO2 concentration and other forcings are kept at the pre-industrial level. We will present results of idealized deforestation experiments and other sensitivity runs with the CMIP6-version of MPI-ESM, which will be part of the later multi-model comparison. A special focus will be put on less well investigated aspects of LULCC that the idealized setup is particularly well suited for studying, such as non-linearities of the model response to the deforestation forcing and detectability of the signal over time.

  20. Cyber situation awareness: modeling detection of cyber attacks with instance-based learning theory.

    PubMed

    Dutt, Varun; Ahn, Young-Suk; Gonzalez, Cleotilde

    2013-06-01

    To determine the effects of an adversary's behavior on the defender's accurate and timely detection of network threats. Cyber attacks cause major work disruption. It is important to understand how a defender's behavior (experience and tolerance to threats), as well as adversarial behavior (attack strategy), might impact the detection of threats. In this article, we use cognitive modeling to make predictions regarding these factors. Different model types representing a defender, based on Instance-Based Learning Theory (IBLT), faced different adversarial behaviors. A defender's model was defined by experience of threats: threat-prone (90% threats and 10% nonthreats) and nonthreat-prone (10% threats and 90% nonthreats); and different tolerance levels to threats: risk-averse (model declares a cyber attack after perceiving one threat out of eight total) and risk-seeking (model declares a cyber attack after perceiving seven threats out of eight total). Adversarial behavior is simulated by considering different attack strategies: patient (threats occur late) and impatient (threats occur early). For an impatient strategy, risk-averse models with threat-prone experiences show improved detection compared with risk-seeking models with nonthreat-prone experiences; however, the same is not true for a patient strategy. Based upon model predictions, a defender's prior threat experiences and his or her tolerance to threats are likely to predict detection accuracy; but considering the nature of adversarial behavior is also important. Decision-support tools that consider the role of a defender's experience and tolerance to threats along with the nature of adversarial behavior are likely to improve a defender's overall threat detection.

  1. The Effects of Using Drawings in Developing Young Children's Mathematical Word Problem Solving: A Design Experiment with Third-Grade Hungarian Students

    ERIC Educational Resources Information Center

    Csikos, Csaba; Szitanyi, Judit; Kelemen, Rita

    2012-01-01

    The present study aims to investigate the effects of a design experiment developed for third-grade students in the field of mathematics word problems. The main focus of the program was developing students' knowledge about word problem solving strategies with an emphasis on the role of visual representations in mathematical modeling. The experiment…

  2. Student Teacher Educational Attitude Changes in Year-Long Placements Examined from a Cognitive Dissonance Framework. Teacher Education Forum; Volume 4, Number 16.

    ERIC Educational Resources Information Center

    Mahan, James M.; Lacefield, Warren E.

    The purpose of the two studies reported in this paper are (1) to extend knowledge about the effects of longer field experience with multiple role models (supervising teachers) upon student teachers' value orientations toward education and schooling; and (2) to document the effects that the student teaching experiences have upon the educational…

  3. First learned words are not forgotten: Age-of-acquisition effects in the tip-of-the-tongue experience.

    PubMed

    Navarrete, Eduardo; Pastore, Massimiliano; Valentini, Rosa; Peressotti, Francesca

    2015-10-01

    A large body of evidence indicates that the age at which a word is acquired predicts the time required to retrieve that word during speech production. Here we explored whether age of acquisition also predicts the experience of being unable to produce a known word at a particular moment. Italian speakers named a sequence of pictures in Experiment 1 or retrieved a word as a response to a definition in Experiment 2. In both experiments, the participants were instructed to indicate when they were in a tip-of-the-tongue (TOT) state. Generalized mixed-effects models performed on the TOT and correct responses revealed that word frequency and age of acquisition predicted the TOT states. Specifically, low-frequency words elicited more TOTs than did high-frequency words, replicating previous findings. In addition, late-acquired words elicited more TOTs than did early-acquired words. Further analyses revealed that the age of acquisition was a better predictor of TOTs than was word frequency. The effects of age of acquisition were similar with subjective and objective measures of age of acquisition, and persisted when several psycholinguistic variables were taken into consideration as predictors in the generalized mixed-effects models. We explained these results in terms of weaker semantic-to-phonological connections in the speech production system for late-acquired words.

  4. MODELING SUBSTRATE TRANSPORT INTO BIOFILMS: ROLE OF MULTIPLE IONS AND PH EFFECTS

    EPA Science Inventory

    Steady-state substrate utilization in biofilms has traditionally been modeled by coupling Fickian diffusion with Monod reaction kinetics. An inherent assumption in most of the previous models was that the pH remains constant within the biofilm. Experiments have shown differences ...

  5. Effects of Solar Geoengineering on Meridional Energy Transport and the ITCZ

    NASA Astrophysics Data System (ADS)

    Russotto, R. D.; Ackerman, T. P.; Frierson, D. M.

    2016-12-01

    The polar amplification of warming and the ability of the intertropical convergence zone (ITCZ) to shift to the north or south are two very important problems in climate science. Examining these behaviors in global climate models (GCMs) running solar geoengineering experiments is helpful not only for predicting the effects of solar geoengineering, but also for understanding how these processes work under increased CO2. Both polar amplification and ITCZ shifts are closely related to the meridional transport of moist static energy (MSE) by the atmosphere. In this study we examine changes in MSE transport in 10 fully coupled GCMs in Experiment G1 of the Geoengineering Model Intercomparison Project, in which the solar constant is reduced to compensate for abruptly quadrupled CO2 concentrations. In this experiment, poleward MSE transport decreases relative to preindustrial conditions in all models, in contrast to the CMIP5 abrupt4xCO2 experiment, in which poleward MSE transport increases. The increase in poleward MSE transport under increased CO2 is due to latent heat transport, as specific humidity increases faster in the tropics than at the poles; this mechanism is not present under G1 conditions, so the reduction in dry static energy transport due to a weakened equator-to-pole temperature gradient leads to weaker energy transport overall. Changes in cross-equatorial MSE transport in G1, meanwhile, are anticorrelated with shifts in the ITCZ. The northward ITCZ shift in G1 is 0.14 degrees in the multi-model mean and ranges from -0.33 to 0.89 degrees between the models. We examine the specific forcing and feedback terms responsible for changes in MSE transport in G1 by running experiments with a moist energy balance model. This work will help identify the largest sources of uncertainty regarding ITCZ shifts under solar geoengineering, and will help improve our understanding of the reasons for the residual polar amplification that occurs in the G1 experiment.

  6. A biologically inspired neural model for visual and proprioceptive integration including sensory training.

    PubMed

    Saidi, Maryam; Towhidkhah, Farzad; Gharibzadeh, Shahriar; Lari, Abdolaziz Azizi

    2013-12-01

    Humans perceive the surrounding world by integration of information through different sensory modalities. Earlier models of multisensory integration rely mainly on traditional Bayesian and causal Bayesian inferences for single causal (source) and two causal (for two senses such as visual and auditory systems), respectively. In this paper a new recurrent neural model is presented for integration of visual and proprioceptive information. This model is based on population coding which is able to mimic multisensory integration of neural centers in the human brain. The simulation results agree with those achieved by casual Bayesian inference. The model can also simulate the sensory training process of visual and proprioceptive information in human. Training process in multisensory integration is a point with less attention in the literature before. The effect of proprioceptive training on multisensory perception was investigated through a set of experiments in our previous study. The current study, evaluates the effect of both modalities, i.e., visual and proprioceptive training and compares them with each other through a set of new experiments. In these experiments, the subject was asked to move his/her hand in a circle and estimate its position. The experiments were performed on eight subjects with proprioception training and eight subjects with visual training. Results of the experiments show three important points: (1) visual learning rate is significantly more than that of proprioception; (2) means of visual and proprioceptive errors are decreased by training but statistical analysis shows that this decrement is significant for proprioceptive error and non-significant for visual error, and (3) visual errors in training phase even in the beginning of it, is much less than errors of the main test stage because in the main test, the subject has to focus on two senses. The results of the experiments in this paper is in agreement with the results of the neural model simulation.

  7. Determination of wind tunnel constraint effects by a unified pressure signature method. Part 2: Application to jet-in-crossflow

    NASA Technical Reports Server (NTRS)

    Hackett, J. E.; Sampath, S.; Phillips, C. G.

    1981-01-01

    The development of an improved jet-in-crossflow model for estimating wind tunnel blockage and angle-of-attack interference is described. Experiments showed that the simpler existing models fall seriously short of representing far-field flows properly. A new, vortex-source-doublet (VSD) model was therefore developed which employs curved trajectories and experimentally-based singularity strengths. The new model is consistent with existing and new experimental data and it predicts tunnel wall (i.e. far-field) pressures properly. It is implemented as a preprocessor to the wall-pressure-signature-based tunnel interference predictor. The supporting experiments and theoretical studies revealed some new results. Comparative flow field measurements with 1-inch "free-air" and 3-inch impinging jets showed that vortex penetration into the flow, in diameters, was almost unaltered until 'hard' impingement occurred. In modeling impinging cases, a 'plume redirection' term was introduced which is apparently absent in previous models. The effects of this term were found to be very significant.

  8. Health Professionals' Explanations of Suicidal Behaviour: Effects of Professional Group, Theoretical Intervention Model, and Patient Suicide Experience.

    PubMed

    Rothes, Inês Areal; Henriques, Margarida Rangel

    2017-12-01

    In a help relation with a suicidal person, the theoretical models of suicidality can be essential to guide the health professional's comprehension of the client/patient. The objectives of this study were to identify health professionals' explanations of suicidal behaviors and to study the effects of professional group, theoretical intervention models, and patient suicide experience in professionals' representations. Two hundred and forty-two health professionals filled out a self-report questionnaire. Exploratory principal components analysis was used. Five explanatory models were identified: psychological suffering, affective cognitive, sociocommunicational, adverse life events, and psychopathological. Results indicated that the psychological suffering and psychopathological models were the most valued by the professionals, while the sociocommunicational was seen as the least likely to explain suicidal behavior. Differences between professional groups were found. We concluded that training and reflection on theoretical models in general and in communicative issues in particular are needed in the education of health professionals.

  9. Predicting herbicide mixture effects on multiple algal species using mixture toxicity models.

    PubMed

    Nagai, Takashi

    2017-10-01

    The validity of the application of mixture toxicity models, concentration addition and independent action, to a species sensitivity distribution (SSD) for calculation of a multisubstance potentially affected fraction was examined in laboratory experiments. Toxicity assays of herbicide mixtures using 5 species of periphytic algae were conducted. Two mixture experiments were designed: a mixture of 5 herbicides with similar modes of action and a mixture of 5 herbicides with dissimilar modes of action, corresponding to the assumptions of the concentration addition and independent action models, respectively. Experimentally obtained mixture effects on 5 algal species were converted to the fraction of affected (>50% effect on growth rate) species. The predictive ability of the concentration addition and independent action models with direct application to SSD depended on the mode of action of chemicals. That is, prediction was better for the concentration addition model than the independent action model for the mixture of herbicides with similar modes of action. In contrast, prediction was better for the independent action model than the concentration addition model for the mixture of herbicides with dissimilar modes of action. Thus, the concentration addition and independent action models could be applied to SSD in the same manner as for a single-species effect. The present study to validate the application of the concentration addition and independent action models to SSD supports the usefulness of the multisubstance potentially affected fraction as the index of ecological risk. Environ Toxicol Chem 2017;36:2624-2630. © 2017 SETAC. © 2017 SETAC.

  10. Effect of wave action on near-well zone cleaning

    NASA Astrophysics Data System (ADS)

    Pen'kovskii, V. I.; Korsakova, N. K.

    2017-10-01

    Drilling filtrate invasion into the producing formation and native water accumulating of the near-well zone in well operation reduce the well productivity. As a result of that, depending on characteristic capillary pressure scale and differential pressure drawdown, oil production rate may become lower than expected one. In this paper, it is considered the hysteresis effects of capillary pressure after reversion of displacement. As applied to laboratory experiment conditions, the solution of problem of oil flow in formation model with a pressure drop on the model sides harmonically varied with time is presented. It was estimated a range of fluid vibration effective action on the near-well zone cleaning from capillary locking water. The plant simulating extraction of oil from formation using widely practised sucker-rod pump has been created. Formation model is presented as a slot filled with broken glass between two plates. In the process, natural oil and sodium chloride solution were used as working fluids. The experiments qualitatively confirm a positive effect of jack pumps on the near-well zone cleaning.

  11. Effect of antifreeze protein on heterogeneous ice nucleation based on a two-dimensional random-field Ising model

    NASA Astrophysics Data System (ADS)

    Dong, Zhen; Wang, Jianjun; Zhou, Xin

    2017-05-01

    Antifreeze proteins (AFPs) are the key biomolecules that protect many species from suffering the extreme conditions. Their unique properties of antifreezing provide the potential of a wide range of applications. Inspired by the present experimental approaches of creating an antifreeze surface by coating AFPs, here we present a two-dimensional random-field lattice Ising model to study the effect of AFPs on heterogeneous ice nucleation. The model shows that both the size and the free-energy effect of individual AFPs and their surface coverage dominate the antifreeze capacity of an AFP-coated surface. The simulation results are consistent with the recent experiments qualitatively, revealing the origin of the surprisingly low antifreeze capacity of an AFP-coated surface when the coverage is not particularly high as shown in experiment. These results will hopefully deepen our understanding of the antifreeze effects and thus be potentially useful for designing novel antifreeze coating materials based on biomolecules.

  12. Physically-based strength model of tantalum incorporating effects of temperature, strain rate and pressure

    DOE PAGES

    Lim, Hojun; Battaile, Corbett C.; Brown, Justin L.; ...

    2016-06-14

    In this work, we develop a tantalum strength model that incorporates e ects of temperature, strain rate and pressure. Dislocation kink-pair theory is used to incorporate temperature and strain rate e ects while the pressure dependent yield is obtained through the pressure dependent shear modulus. Material constants used in the model are parameterized from tantalum single crystal tests and polycrystalline ramp compression experiments. It is shown that the proposed strength model agrees well with the temperature and strain rate dependent yield obtained from polycrystalline tantalum experiments. Furthermore, the model accurately reproduces the pressure dependent yield stresses up to 250 GPa.more » The proposed strength model is then used to conduct simulations of a Taylor cylinder impact test and validated with experiments. This approach provides a physically-based multi-scale strength model that is able to predict the plastic deformation of polycrystalline tantalum through a wide range of temperature, strain and pressure regimes.« less

  13. Identifying different learning styles to enhance the learning experience.

    PubMed

    Anderson, Irene

    2016-10-12

    Identifying your preferred learning style can be a useful way to optimise learning opportunities, and can help learners to recognise their strengths and areas for development in the way that learning takes place. It can also help teachers (educators) to recognise where additional activities are required to ensure the learning experience is robust and effective. There are several models available that may be used to identify learning styles. This article discusses these models and considers their usefulness in healthcare education. Models of teaching styles are also considered.

  14. Comparing different kinds of words and word-word relations to test an habituation model of priming.

    PubMed

    Rieth, Cory A; Huber, David E

    2017-06-01

    Huber and O'Reilly (2003) proposed that neural habituation exists to solve a temporal parsing problem, minimizing blending between one word and the next when words are visually presented in rapid succession. They developed a neural dynamics habituation model, explaining the finding that short duration primes produce positive priming whereas long duration primes produce negative repetition priming. The model contains three layers of processing, including a visual input layer, an orthographic layer, and a lexical-semantic layer. The predicted effect of prime duration depends both on this assumed representational hierarchy and the assumption that synaptic depression underlies habituation. The current study tested these assumptions by comparing different kinds of words (e.g., words versus non-words) and different kinds of word-word relations (e.g., associative versus repetition). For each experiment, the predictions of the original model were compared to an alternative model with different representational assumptions. Experiment 1 confirmed the prediction that non-words and inverted words require longer prime durations to eliminate positive repetition priming (i.e., a slower transition from positive to negative priming). Experiment 2 confirmed the prediction that associative priming increases and then decreases with increasing prime duration, but remains positive even with long duration primes. Experiment 3 replicated the effects of repetition and associative priming using a within-subjects design and combined these effects by examining target words that were expected to repeat (e.g., viewing the target word 'BACK' after the prime phrase 'back to'). These results support the originally assumed representational hierarchy and more generally the role of habituation in temporal parsing and priming. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Does the growth response of woody plants to elevated CO2 increase with temperature? A model-oriented meta-analysis.

    PubMed

    Baig, Sofia; Medlyn, Belinda E; Mercado, Lina M; Zaehle, Sönke

    2015-12-01

    The temperature dependence of the reaction kinetics of the Rubisco enzyme implies that, at the level of a chloroplast, the response of photosynthesis to rising atmospheric CO2 concentration (Ca ) will increase with increasing air temperature. Vegetation models incorporating this interaction predict that the response of net primary productivity (NPP) to elevated CO2 (eCa ) will increase with rising temperature and will be substantially larger in warm tropical forests than in cold boreal forests. We tested these model predictions against evidence from eCa experiments by carrying out two meta-analyses. Firstly, we tested for an interaction effect on growth responses in factorial eCa  × temperature experiments. This analysis showed a positive, but nonsignificant interaction effect (95% CI for above-ground biomass response = -0.8, 18.0%) between eCa and temperature. Secondly, we tested field-based eCa experiments on woody plants across the globe for a relationship between the eCa effect on plant biomass and mean annual temperature (MAT). This second analysis showed a positive but nonsignificant correlation between the eCa response and MAT. The magnitude of the interactions between CO2 and temperature found in both meta-analyses were consistent with model predictions, even though both analyses gave nonsignificant results. Thus, we conclude that it is not possible to distinguish between the competing hypotheses of no interaction vs. an interaction based on Rubisco kinetics from the available experimental database. Experiments in a wider range of temperature zones are required. Until such experimental data are available, model predictions should aim to incorporate uncertainty about this interaction. © 2015 John Wiley & Sons Ltd.

  16. Laboratory-scale experiments and numerical modeling of cosolvent flushing of multi-component NAPLs in saturated porous media.

    PubMed

    Agaoglu, Berken; Scheytt, Traugott; Copty, Nadim K

    2012-10-01

    This study examines the mechanistic processes governing multiphase flow of a water-cosolvent-NAPL system in saturated porous media. Laboratory batch and column flushing experiments were conducted to determine the equilibrium properties of pure NAPL and synthetically prepared NAPL mixtures as well as NAPL recovery mechanisms for different water-ethanol contents. The effect of contact time was investigated by considering different steady and intermittent flow velocities. A modified version of multiphase flow simulator (UTCHEM) was used to compare the multiphase model simulations with the column experiment results. The effect of employing different grid geometries (1D, 2D, 3D), heterogeneity and different initial NAPL saturation configurations was also examined in the model. It is shown that the change in velocity affects the mass transfer rate between phases as well as the ultimate NAPL recovery percentage. The experiments with low flow rate flushing of pure NAPL and the 3D UTCHEM simulations gave similar effluent concentrations and NAPL cumulative recoveries. Model simulations over-estimated NAPL recovery for high specific discharges and rate-limited mass transfer, suggesting a constant mass transfer coefficient for the entire flushing experiment may not be valid. When multi-component NAPLs are present, the dissolution rate of individual organic compounds (namely, toluene and benzene) into the ethanol-water flushing solution is found not to correlate with their equilibrium solubility values. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Topological phases in the Haldane model with spin–spin on-site interactions

    NASA Astrophysics Data System (ADS)

    Rubio-García, A.; García-Ripoll, J. J.

    2018-04-01

    Ultracold atom experiments allow the study of topological insulators, such as the non-interacting Haldane model. In this work we study a generalization of the Haldane model with spin–spin on-site interactions that can be implemented on such experiments. We focus on measuring the winding number, a topological invariant, of the ground state, which we compute using a mean-field calculation that effectively captures long-range correlations and a matrix product state computation in a lattice with 64 sites. Our main result is that we show how the topological phases present in the non-interacting model survive until the interactions are comparable to the kinetic energy. We also demonstrate the accuracy of our mean-field approach in efficiently capturing long-range correlations. Based on state-of-the-art ultracold atom experiments, we propose an implementation of our model that can give information about the topological phases.

  18. Cardiovascular system simulation in biomedical engineering education.

    NASA Technical Reports Server (NTRS)

    Rideout, V. C.

    1972-01-01

    Use of complex cardiovascular system models, in conjunction with a large hybrid computer, in biomedical engineering courses. A cardiovascular blood pressure-flow model, driving a compartment model for the study of dye transport, was set up on the computer for use as a laboratory exercise by students who did not have the computer experience or skill to be able to easily set up such a simulation involving some 27 differential equations running at 'real time' rate. The students were given detailed instructions regarding the model, and were then able to study effects such as those due to septal and valve defects upon the pressure, flow, and dye dilution curves. The success of this experiment in the use of involved models in engineering courses was such that it seems that this type of laboratory exercise might be considered for use in physiology courses as an adjunct to animal experiments.

  19. A statistical simulation model for field testing of non-target organisms in environmental risk assessment of genetically modified plants.

    PubMed

    Goedhart, Paul W; van der Voet, Hilko; Baldacchino, Ferdinando; Arpaia, Salvatore

    2014-04-01

    Genetic modification of plants may result in unintended effects causing potentially adverse effects on the environment. A comparative safety assessment is therefore required by authorities, such as the European Food Safety Authority, in which the genetically modified plant is compared with its conventional counterpart. Part of the environmental risk assessment is a comparative field experiment in which the effect on non-target organisms is compared. Statistical analysis of such trials come in two flavors: difference testing and equivalence testing. It is important to know the statistical properties of these, for example, the power to detect environmental change of a given magnitude, before the start of an experiment. Such prospective power analysis can best be studied by means of a statistical simulation model. This paper describes a general framework for simulating data typically encountered in environmental risk assessment of genetically modified plants. The simulation model, available as Supplementary Material, can be used to generate count data having different statistical distributions possibly with excess-zeros. In addition the model employs completely randomized or randomized block experiments, can be used to simulate single or multiple trials across environments, enables genotype by environment interaction by adding random variety effects, and finally includes repeated measures in time following a constant, linear or quadratic pattern in time possibly with some form of autocorrelation. The model also allows to add a set of reference varieties to the GM plants and its comparator to assess the natural variation which can then be used to set limits of concern for equivalence testing. The different count distributions are described in some detail and some examples of how to use the simulation model to study various aspects, including a prospective power analysis, are provided.

  20. A statistical simulation model for field testing of non-target organisms in environmental risk assessment of genetically modified plants

    PubMed Central

    Goedhart, Paul W; van der Voet, Hilko; Baldacchino, Ferdinando; Arpaia, Salvatore

    2014-01-01

    Genetic modification of plants may result in unintended effects causing potentially adverse effects on the environment. A comparative safety assessment is therefore required by authorities, such as the European Food Safety Authority, in which the genetically modified plant is compared with its conventional counterpart. Part of the environmental risk assessment is a comparative field experiment in which the effect on non-target organisms is compared. Statistical analysis of such trials come in two flavors: difference testing and equivalence testing. It is important to know the statistical properties of these, for example, the power to detect environmental change of a given magnitude, before the start of an experiment. Such prospective power analysis can best be studied by means of a statistical simulation model. This paper describes a general framework for simulating data typically encountered in environmental risk assessment of genetically modified plants. The simulation model, available as Supplementary Material, can be used to generate count data having different statistical distributions possibly with excess-zeros. In addition the model employs completely randomized or randomized block experiments, can be used to simulate single or multiple trials across environments, enables genotype by environment interaction by adding random variety effects, and finally includes repeated measures in time following a constant, linear or quadratic pattern in time possibly with some form of autocorrelation. The model also allows to add a set of reference varieties to the GM plants and its comparator to assess the natural variation which can then be used to set limits of concern for equivalence testing. The different count distributions are described in some detail and some examples of how to use the simulation model to study various aspects, including a prospective power analysis, are provided. PMID:24834325

  1. The effects of recall-concurrent visual-motor distraction on picture and word recall.

    PubMed

    Warren, M W

    1977-05-01

    The dual-coding model (Paivio, 1971, 1975) predicts a larger imaginal component in the recall of pictures relative to words and a larger imaginal component in the recall of concrete words relative to abstract words. These predictions were tested by examining the effect of a recall-concurrent imagery-suppression task (pursuit-rotor tracking) on the recall of pictures vs picture labels and on the recall of concrete words vs abstract words. The results showed that recall-concurrent pursuit-rotor tracking interfered with picture recall, but not word recall (Experiments 1 and 2); however, there was no evidence of an effect of recall-concurrent tracking on the recall of concrete words (Experiment 3). The results suggested a revision of the dual-coding model.

  2. Numerical experiments with a general circulation model concerning the stratospheric distribution of ozone

    NASA Technical Reports Server (NTRS)

    Kurzeja, R. J.; Haggard, K. V.; Grose, W. L.

    1981-01-01

    Three experiments have been performed using a three-dimensional, spectral quasi-geostrophic model in order to investigate the sensitivity of ozone transport to tropospheric orographic and thermal effects and to the zonal wind distribution. In the first experiment, the ozone distribution averaged over the last 30 days of a 60 day transport simulation was determined; in the second experiment, the transport simulation was repeated, but nonzonal orographic and thermal forcing was omitted; and in the final experiment, the simulation was conducted with the intensity and position of the stratospheric jets altered by addition of a Newtonian cooling term to the zonal-mean diabatic heating rate. Results of the three experiments are summarized by comparing the zonal-mean ozone distribution, the amplitude of eddy geopotential height, the zonal winds, and zonal-mean diabatic heating.

  3. Dendritic Alloy Solidification Experiment (DASE)

    NASA Technical Reports Server (NTRS)

    Beckermann, C.; Karma, A.; Steinbach, I.; deGroh, H. C., III

    2001-01-01

    A space experiment, and supporting ground-based research, is proposed to study the microstructural evolution in free dendritic growth from a supercooled melt of the transparent model alloy succinonitrile-acetone (SCN-ACE). The research is relevant to equiaxed solidification of metal alloy castings. The microgravity experiment will establish a benchmark for testing of equiaxed dendritic growth theories, scaling laws, and models in the presence of purely diffusive, coupled heat and solute transport, without the complicating influences of melt convection. The specific objectives are to: determine the selection of the dendrite tip operating state, i.e. the growth velocity and tip radius, for free dendritic growth of succinonitrile-acetone alloys; determine the growth morphology and sidebranching behavior for freely grown alloy dendrites; determine the effects of the thermal/solutal interactions in the growth of an assemblage of equiaxed alloy crystals; determine the effects of melt convection on the free growth of alloy dendrites; measure the surface tension anisotropy strength of succinon itrile -acetone alloys establish a theoretical and modeling framework for the experiments. Microgravity experiments on equiaxed dendritic growth of alloy dendrites have not been performed in the past. The proposed experiment builds on the Isothermal Dendritic Growth Experiment (IDGE) of Glicksman and coworkers, which focused on the steady growth of a single crystal from pure supercooled melts (succinonitrile and pivalic acid). It also extends the Equiaxed Dendritic Solidification Experiment (EDSE) of the present investigators, which is concerned with the interactions and transients arising in the growth of an assemblage of equiaxed crystals (succinonitrile). However, these experiments with pure substances are not able to address the issues related to coupled heat and solute transport in growth of alloy dendrites.

  4. Orthotopic model of canine osteosarcoma in athymic rats for evaluation of stereotactic radiotherapy.

    PubMed

    Schwartz, Anthony L; Custis, James T; Harmon, Joseph F; Powers, Barbara E; Chubb, Laura S; LaRue, Susan M; Ehrhart, Nicole P; Ryan, Stewart D

    2013-03-01

    To develop an orthotopic model of canine osteosarcoma in athymic rats as a model for evaluating the effects of stereotactic radiotherapy (SRT) on osteosarcoma cells. 26 athymic nude rats. 3 experiments were performed. In the first 2 experiments, rats were injected with 1 × 10(6) Abrams canine osteosarcoma cells into the proximal aspect of the tibia (n = 12) or distal aspect of the femur (6). Tumor engraftment and progression were monitored weekly via radiography, luciferase imaging, and measurement of urine pyridinoline concentration for 5 weeks and histologic evaluation after euthanasia. In the third experiment, 8 rats underwent canine osteosarcoma cell injection into the distal aspect of the femur and SRT was administered to the affected area in three 12-Gy fractions delivered on consecutive days (total radiation dose, 36 Gy). Percentage tumor necrosis and urinary pyridinoline concentrations were used to assess local tumor control. The short-term effect of SRT on skin was also evaluated. Tumors developed in 10 of 12 tibial sites and all 14 femoral sites. Administration of SRT to rats with femoral osteosarcoma was feasible and successful. Mean tumor necrosis of 95% was achieved histologically, and minimal adverse skin effects were observed. The orthotopic model of canine osteosarcoma in rats developed in this study was suitable for evaluating the effects of local tumor control and can be used in future studies to evaluate optimization of SRT duration, dose, and fractionation schemes. The model could also allow evaluation of other treatments in combination with SRT, such as chemotherapy or bisphosphonate, radioprotectant, or parathyroid hormone treatment.

  5. Systems-Oriented Workplace Learning Experiences for Early Learners: Three Models.

    PubMed

    O'Brien, Bridget C; Bachhuber, Melissa R; Teherani, Arianne; Iker, Theresa M; Batt, Joanne; O'Sullivan, Patricia S

    2017-05-01

    Early workplace learning experiences may be effective for learning systems-based practice. This study explores systems-oriented workplace learning experiences (SOWLEs) for early learners to suggest a framework for their development. The authors used a two-phase qualitative case study design. In Phase 1 (spring 2014), they prepared case write-ups based on transcribed interviews from 10 SOWLE leaders at the authors' institution and, through comparative analysis of cases, identified three SOWLE models. In Phase 2 (summer 2014), studying seven 8-week SOWLE pilots, the authors used interview and observational data collected from the seven participating medical students, two pharmacy students, and site leaders to construct case write-ups of each pilot and to verify and elaborate the models. In Model 1, students performed specific patient care activities that addressed a system gap. Some site leaders helped students connect the activities to larger systems problems and potential improvements. In Model 2, students participated in predetermined systems improvement (SI) projects, gaining experience in the improvement process. Site leaders had experience in SI and often had significant roles in the projects. In Model 3, students worked with key stakeholders to develop a project and conduct a small test of change. They experienced most elements of an improvement cycle. Site leaders often had experience with SI and knew how to guide and support students' learning. Each model could offer systems-oriented learning opportunities provided that key elements are in place including site leaders facile in SI concepts and able to guide students in SOWLE activities.

  6. Gedanken Experiments in Educational Cost Effectiveness

    ERIC Educational Resources Information Center

    Brudner, Harvey J.

    1978-01-01

    Discusses the effectiveness of cost determining techniques in education. The areas discussed are: education and management; cost-effectiveness models; figures of merit determination; and the implications as they relate to the areas of audio-visual and computer educational technology. (Author/GA)

  7. A dual memory theory of the testing effect.

    PubMed

    Rickard, Timothy C; Pan, Steven C

    2017-06-05

    A new theoretical framework for the testing effect-the finding that retrieval practice is usually more effective for learning than are other strategies-is proposed, the empirically supported tenet of which is that separate memories form as a consequence of study and test events. A simplest case quantitative model is derived from that framework for the case of cued recall. With no free parameters, that model predicts both proportion correct in the test condition and the magnitude of the testing effect across 10 experiments conducted in our laboratory, experiments that varied with respect to material type, retention interval, and performance in the restudy condition. The model also provides the first quantitative accounts of (a) the testing effect as a function of performance in the restudy condition, (b) the upper bound magnitude of the testing effect, (c) the effect of correct answer feedback, (d) the testing effect as a function of retention interval for the cases of feedback and no feedback, and (e) the effect of prior learning method on subsequent learning through testing. Candidate accounts of several other core phenomena in the literature, including test-potentiated learning, recognition versus cued recall training effects, cued versus free recall final test effects, and other select transfer effects, are also proposed. Future prospects and relations to other theories are discussed.

  8. Analytical determination of space station response to crew motion and design of suspension system for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Liu, F. C.

    1986-01-01

    The objective of this investigation is to make analytical determination of the acceleration produced by crew motion in an orbiting space station and define design parameters for the suspension system of microgravity experiments. A simple structural model for simulation of the IOC space station is proposed. Mathematical formulation of this model provides the engineers a simple and direct tool for designing an effective suspension system.

  9. The Effect of Interior Design Improvements on the Quality of Learning for Graduate Level Military Officer Students

    DTIC Science & Technology

    1991-05-13

    for the model classroom. Nevertheless, findings about the impact of interior design improvements 14 on student perceptions about the physical...from the impact of the model classroom interior design improvements on student perceptions about their physical learning environment. Delimitations of...their perceptions about places through personal experience. The intensity and quality of these personal experiences have a greater impact on people’s

  10. Josephson A/D Converter Development.

    DTIC Science & Technology

    1981-10-01

    by Zappe and A Landman [20]. They conclude that the simple model of the Josephson effect is applicable up to frequencies at least as high (a) as 300...GHz. B. Time-Domain Experiments 4ooF so The early high - frequency experiments with Josephson devices I .O suggested their use as very fast logic switches...exactly as for the phenomenological model . The tunneling pacitive current paths dominate the circuit at high frequencies . current is the sum of two

  11. Backward deletion to minimize prediction errors in models from factorial experiments with zero to six center points

    NASA Technical Reports Server (NTRS)

    Holms, A. G.

    1980-01-01

    Population model coefficients were chosen to simulate a saturated 2 to the fourth power fixed effects experiment having an unfavorable distribution of relative values. Using random number studies, deletion strategies were compared that were based on the F distribution, on an order statistics distribution of Cochran's, and on a combination of the two. Results of the comparisons and a recommended strategy are given.

  12. Eliciting mixed emotions: a meta-analysis comparing models, types, and measures

    PubMed Central

    Berrios, Raul; Totterdell, Peter; Kellett, Stephen

    2015-01-01

    The idea that people can experience two oppositely valenced emotions has been controversial ever since early attempts to investigate the construct of mixed emotions. This meta-analysis examined the robustness with which mixed emotions have been elicited experimentally. A systematic literature search identified 63 experimental studies that instigated the experience of mixed emotions. Studies were distinguished according to the structure of the underlying affect model—dimensional or discrete—as well as according to the type of mixed emotions studied (e.g., happy-sad, fearful-happy, positive-negative). The meta-analysis using a random-effects model revealed a moderate to high effect size for the elicitation of mixed emotions (dIG+ = 0.77), which remained consistent regardless of the structure of the affect model, and across different types of mixed emotions. Several methodological and design moderators were tested. Studies using the minimum index (i.e., the minimum value between a pair of opposite valenced affects) resulted in smaller effect sizes, whereas subjective measures of mixed emotions increased the effect sizes. The presence of more women in the samples was also associated with larger effect sizes. The current study indicates that mixed emotions are a robust, measurable and non-artifactual experience. The results are discussed in terms of the implications for an affect system that has greater versatility and flexibility than previously thought. PMID:25926805

  13. A Model for Effective Teaching and Learning in Research Methods.

    ERIC Educational Resources Information Center

    Poindexter, Paula M.

    1998-01-01

    Proposes a teaching model for making research relevant. Presents a case study of the model as used in advertising and public relations research classes. Notes that the model consists of a knowledge base, team process, a realistic goal-oriented experience, self-management, expert consultation, and evaluation and synthesis. Discusses resulting…

  14. Experience with k-epsilon turbulence models for heat transfer computations in rotating

    NASA Technical Reports Server (NTRS)

    Tekriwal, Prabbat

    1995-01-01

    This viewgraph presentation discusses geometry and flow configuration, effect of y+ on heat transfer computations, standard and extended k-epsilon turbulence model results with wall function, low-Re model results (the Lam-Bremhorst model without wall function), a criterion for flow reversal in a radially rotating square duct, and a summary.

  15. Statistical models for the analysis and design of digital polymerase chain (dPCR) experiments

    USGS Publications Warehouse

    Dorazio, Robert; Hunter, Margaret

    2015-01-01

    Statistical methods for the analysis and design of experiments using digital PCR (dPCR) have received only limited attention and have been misused in many instances. To address this issue and to provide a more general approach to the analysis of dPCR data, we describe a class of statistical models for the analysis and design of experiments that require quantification of nucleic acids. These models are mathematically equivalent to generalized linear models of binomial responses that include a complementary, log–log link function and an offset that is dependent on the dPCR partition volume. These models are both versatile and easy to fit using conventional statistical software. Covariates can be used to specify different sources of variation in nucleic acid concentration, and a model’s parameters can be used to quantify the effects of these covariates. For purposes of illustration, we analyzed dPCR data from different types of experiments, including serial dilution, evaluation of copy number variation, and quantification of gene expression. We also showed how these models can be used to help design dPCR experiments, as in selection of sample sizes needed to achieve desired levels of precision in estimates of nucleic acid concentration or to detect differences in concentration among treatments with prescribed levels of statistical power.

  16. Corvid caching: Insights from a cognitive model.

    PubMed

    van der Vaart, Elske; Verbrugge, Rineke; Hemelrijk, Charlotte K

    2011-07-01

    Caching and recovery of food by corvids is well-studied, but some ambiguous results remain. To help clarify these, we built a computational cognitive model. It is inspired by similar models built for humans, and it assumes that memory strength depends on frequency and recency of use. We compared our model's behavior to that of real birds in previously published experiments. Our model successfully replicated the outcomes of two experiments on recovery behavior and two experiments on cache site choice. Our "virtual birds" reproduced declines in recovery accuracy across sessions, revisits to previously emptied cache sites, a lack of correlation between caching and recovery order, and a preference for caching in safe locations. The model also produced two new explanations. First, that Clark's nutcrackers may become less accurate as recovery progresses not because of differential memory for different cache sites, as was once assumed, but because of chance effects. And second, that Western scrub jays may choose their cache sites not on the basis of negative recovery experiences only, as was previously thought, but on the basis of positive recovery experiences instead. Alternatively, both "punishment" and "reward" may be playing a role. We conclude with a set of new insights, a testable prediction, and directions for future work. PsycINFO Database Record (c) 2011 APA, all rights reserved

  17. Water Leak Detection by Using Ground Penetrating Radar, Synthetic Simulation and Four-Dimensional Visualization

    NASA Astrophysics Data System (ADS)

    Al-Shukri, H.; Eyuboglu, S.; Mahdi, H.

    2005-12-01

    Many geophysical techniques have been suggested as candidates for detecting water leakage in water distribution system, including ground penetrating radar (GPR), acoustic devices, and gas sampling devices. A series of laboratory experiments were conducted to determine the validity and effectiveness of GPR in detecting water leakage in metal and plastic PVC pipes. The goal was to derive a practical and robust procedure for detecting such leakage. Initially, prototype laboratory experiments were designed to simulate leaks in both PVC and metal pipe. The experiments were very well controlled and results obtained indicate that GPR is effective in detecting subsurface water leaks. This was followed by an outdoor life size experiments. 50 feet by 30 feet by 5 feet test bed was constructed using local soil and commercial water distribution pipes. A 400 MHz antenna was used to collect three-dimensional GPR data as a function of time for a number of experiments using different type of pipes. Advanced imaging and visualization technology was used to further analyze the data. The UALR Virtual Reality Center CAVE facilities were utilized to accomplish this test. Results obtained indicate that GPR is effective in detecting subsurface water leaks in both pipes. Synthetic models of the GPR signals based on Finite Difference Time Domain Method (FDTD) were built to help select an appropriate equipment configuration (frequency band, type of antenna, and real-time imaging software) prior to data acquisition. The simulation software was used to determine the near-field radiation characteristics of the GPR antenna. Different experimental models were adapted for which observational GPR data was previously collected. Matlab regression analysis was used to generate the incident waves for each model to ensure highly accurate and controlled experiments.

  18. [Effect of muscle biofidelity on thoracic impact biomechanical response of a six-year-old child using finite element method].

    PubMed

    Cui, Shihai; Shan, Leilei; Li, Haiyan; Lu, Wenle; He, Lijuan; Ruan, Shijie

    2017-02-01

    Finite element(FE) model of thorax with high biofidelity is one of the most important methods to investigate thoracic injury mechanism because of the absence of pediatric cadaver experiments. Based on the validated thorax finite element model, the FE models with equivalent muscles and real geometric muscles were developed respectively, and the effect of muscle biofidelity on thoracic injury was analyzed with reconstructing pediatric cadaver thorax impact experiments. The simulation results showed that the thoracic impact force, the maximum displacement and the maximum von-Mises stress of FE models with equivalent muscles were slightly greater than those from FE models with real geometric muscles, and the maximum principal strains of heart and lung were a little lower. And the correlation coefficient between cadaver corridor and FE model with real muscles was also greater than that between cadaver corridor and FE model with equivalent muscles. As a conclusion, the FE models with real geometric muscles can accurately reflect the biomechanical response of thorax during the impact.

  19. Forcing a three-dimensional, hydrostatic, primitive-equation model for application in the surf zone: 2. Application to DUCK94

    NASA Astrophysics Data System (ADS)

    Newberger, P. A.; Allen, J. S.

    2007-08-01

    A three-dimensional primitive-equation model for application to the nearshore surf zone has been developed. This model, an extension of the Princeton Ocean Model (POM), predicts the wave-averaged circulation forced by breaking waves. All of the features of the original POM are retained in the extended model so that applications can be made to regions where breaking waves, stratification, rotation, and wind stress make significant contributions to the flow behavior. In this study we examine the effects of breaking waves and wind stress. The nearshore POM circulation model is embedded within the NearCom community model and is coupled with a wave model. This combined modeling system is applied to the nearshore surf zone off Duck, North Carolina, during the DUCK94 field experiment of October 1994. Model results are compared to observations from this experiment, and the effects of parameter choices are examined. A process study examining the effects of tidal depth variation on depth-dependent wave-averaged currents is carried out. With identical offshore wave conditions and model parameters, the strength and spatial structure of the undertow and of the alongshore current vary systematically with water depth. Some three-dimensional solutions show the development of shear instabilities of the alongshore current. Inclusion of wave-current interactions makes an appreciable difference in the characteristics of the instability.

  20. Inborn and experience-dependent models of categorical brain organization. A position paper

    PubMed Central

    Gainotti, Guido

    2015-01-01

    The present review aims to summarize the debate in contemporary neuroscience between inborn and experience-dependent models of conceptual representations that goes back to the description of category-specific semantic disorders for biological and artifact categories. Experience-dependent models suggest that categorical disorders are the by-product of the differential weighting of different sources of knowledge in the representation of biological and artifact categories. These models maintain that semantic disorders are not really category-specific, because they do not respect the boundaries between different categories. They also argue that the brain structures which are disrupted in a given type of category-specific semantic disorder should correspond to the areas of convergence of the sensory-motor information which play a major role in the construction of that category. Furthermore, they provide a simple interpretation of gender-related categorical effects and are supported by studies assessing the importance of prior experience in the cortical representation of objects On the other hand, inborn models maintain that category-specific semantic disorders reflect the disruption of innate brain networks, which are shaped by natural selection to allow rapid identification of objects that are very relevant for survival. From the empirical point of view, these models are mainly supported by observations of blind subjects, which suggest that visual experience is not necessary for the emergence of category-specificity in the ventral stream of visual processing. The weight of the data supporting experience-dependent and inborn models is thoroughly discussed, stressing the fact observations made in blind subjects are still the subject of intense debate. It is concluded that at the present state of knowledge it is not possible to choose between experience-dependent and inborn models of conceptual representations. PMID:25667570

  1. Narrative Constructions for the Organization of Self Experience: Proof of Concept via Embodied Robotics.

    PubMed

    Mealier, Anne-Laure; Pointeau, Gregoire; Mirliaz, Solène; Ogawa, Kenji; Finlayson, Mark; Dominey, Peter F

    2017-01-01

    It has been proposed that starting from meaning that the child derives directly from shared experience with others, adult narrative enriches this meaning and its structure, providing causal links between unseen intentional states and actions. This would require a means for representing meaning from experience-a situation model-and a mechanism that allows information to be extracted from sentences and mapped onto the situation model that has been derived from experience, thus enriching that representation. We present a hypothesis and theory concerning how the language processing infrastructure for grammatical constructions can naturally be extended to narrative constructions to provide a mechanism for using language to enrich meaning derived from physical experience. Toward this aim, the grammatical construction models are augmented with additional structures for representing relations between events across sentences. Simulation results demonstrate proof of concept for how the narrative construction model supports multiple successive levels of meaning creation which allows the system to learn about the intentionality of mental states, and argument substitution which allows extensions to metaphorical language and analogical problem solving. Cross-linguistic validity of the system is demonstrated in Japanese. The narrative construction model is then integrated into the cognitive system of a humanoid robot that provides the memory systems and world-interaction required for representing meaning in a situation model. In this context proof of concept is demonstrated for how the system enriches meaning in the situation model that has been directly derived from experience. In terms of links to empirical data, the model predicts strong usage based effects: that is, that the narrative constructions used by children will be highly correlated with those that they experience. It also relies on the notion of narrative or discourse function words. Both of these are validated in the experimental literature.

  2. Experimente ueber den Einflusse von Metabolites und Antimetaboliten am Modell von Trichomonas Vaginalis. III. Mitteilung: Experimente mit Essentiellen Fettsaeuren (Experiments on the Influence of Metabolites and Antimetabolites on the Model of Trichomonas Vaginalis. III. Communication: Experiments with Essential Fatty Acids),

    DTIC Science & Technology

    The relationship between the double and trifold unsaturated fatty acids and Trichomonas vaginalis was tested. The experiments aimed at testing the...influence of vitamin F, linolic and linoleic acid upon multiplication of Trichomonas vaginalis . Vitamin F exerts trichomonacidal effect upon... Trichomonas vaginalis cultures. Linolic acid alone does not yet show great differences at concentrations of 0,01 to 0.05 mg/ml, as compared to the controls. At

  3. An imperative need for global change research in tropical forests.

    PubMed

    Zhou, Xuhui; Fu, Yuling; Zhou, Lingyan; Li, Bo; Luo, Yiqi

    2013-09-01

    Tropical forests play a crucial role in regulating regional and global climate dynamics, and model projections suggest that rapid climate change may result in forest dieback or savannization. However, these predictions are largely based on results from leaf-level studies. How tropical forests respond and feedback to climate change is largely unknown at the ecosystem level. Several complementary approaches have been used to evaluate the effects of climate change on tropical forests, but the results are conflicting, largely due to confounding effects of multiple factors. Although altered precipitation and nitrogen deposition experiments have been conducted in tropical forests, large-scale warming and elevated carbon dioxide (CO2) manipulations are completely lacking, leaving many hypotheses and model predictions untested. Ecosystem-scale experiments to manipulate temperature and CO2 concentration individually or in combination are thus urgently needed to examine their main and interactive effects on tropical forests. Such experiments will provide indispensable data and help gain essential knowledge on biogeochemical, hydrological and biophysical responses and feedbacks of tropical forests to climate change. These datasets can also inform regional and global models for predicting future states of tropical forests and climate systems. The success of such large-scale experiments in natural tropical forests will require an international framework to coordinate collaboration so as to meet the challenges in cost, technological infrastructure and scientific endeavor.

  4. Prospective Investigation of the Contrast Avoidance Model of Generalized Anxiety and Worry.

    PubMed

    Crouch, Tara A; Lewis, Jamie A; Erickson, Thane M; Newman, Michelle G

    2017-07-01

    The factors that maintain generalized anxiety disorder (GAD) symptoms and worry over time are not entirely clear. The Contrast Avoidance Model (CAM) postulates that individuals at risk for pathological worry and GAD symptoms uniquely fear emotional shifts from neutral or positive emotions into negative emotional states, and consequently use worry to maintain negative emotion in order to avoid shifts or blunt the effect of negative contrasts. This model has received support in laboratory experiments, but has not been investigated prospectively in the naturalistic context of daily life. The present study tested the CAM in a longitudinal experience sampling study with a subclinical sample. Participants selected to represent a broad range of symptoms (N = 92) completed baseline measures of GAD and depression symptoms, and eight weekly assessments of worry, experiences of negative emotional contrasts during their worst event of the week, and situation-specific negative emotion. Consistent with the CAM, GAD symptoms prospectively predicted higher endorsement of negative contrast experiences as worst events, independent of depression symptoms. Unsurprisingly, higher negative contrasts predicted higher negative emotion. However, both higher baseline GAD symptoms and weekly worry uniquely moderated (reduced) this relationship, providing consistent support for the idea that worry may blunt the emotional effects of contrasts. Depression symptoms did not have the same moderating effect. These findings support the CAM in an ecologically valid context. Copyright © 2016. Published by Elsevier Ltd.

  5. Effect of periodic changes of angle of attack on behavior of airfoils

    NASA Technical Reports Server (NTRS)

    Katzmayr, R

    1922-01-01

    This report presents the results of a series of experiments, which gave some quantitative results on the effect of periodic changes in the direction of the relative air flow against airfoils. The first series of experiments concerned how the angle of attack of the wing model was changed by causing the latter to oscillate about an axis parallel to the span and at right angles to the air flow. The second series embraced all the experiments in which the direction of the air flow itself was periodically changed.

  6. Assessing the chances of success: naïve statistics versus kind experience.

    PubMed

    Hogarth, Robin M; Mukherjee, Kanchan; Soyer, Emre

    2013-01-01

    Additive integration of information is ubiquitous in judgment and has been shown to be effective even when multiplicative rules of probability theory are prescribed. We explore the generality of these findings in the context of estimating probabilities of success in contests. We first define a normative model of these probabilities that takes account of relative skill levels in contests where only a limited number of entrants can win. We then report 4 experiments using a scenario about a competition. Experiments 1 and 2 both elicited judgments of probabilities, and, although participants' responses demonstrated considerable variability, their mean judgments provide a good fit to a simple linear model. Experiment 3 explored choices. Most participants entered most contests and showed little awareness of appropriate probabilities. Experiment 4 investigated effects of providing aids to calculate probabilities, specifically, access to expert advice and 2 simulation tools. With these aids, estimates were accurate and decisions varied appropriately with economic consequences. We discuss implications by considering when additive decision rules are dysfunctional, the interpretation of overconfidence based on contest-entry behavior, and the use of aids to help people make better decisions.

  7. Two Bayesian tests of the GLOMOsys Model.

    PubMed

    Field, Sarahanne M; Wagenmakers, Eric-Jan; Newell, Ben R; Zeelenberg, René; van Ravenzwaaij, Don

    2016-12-01

    Priming is arguably one of the key phenomena in contemporary social psychology. Recent retractions and failed replication attempts have led to a division in the field between proponents and skeptics and have reinforced the importance of confirming certain priming effects through replication. In this study, we describe the results of 2 preregistered replication attempts of 1 experiment by Förster and Denzler (2012). In both experiments, participants first processed letters either globally or locally, then were tested using a typicality rating task. Bayes factor hypothesis tests were conducted for both experiments: Experiment 1 (N = 100) yielded an indecisive Bayes factor of 1.38, indicating that the in-lab data are 1.38 times more likely to have occurred under the null hypothesis than under the alternative. Experiment 2 (N = 908) yielded a Bayes factor of 10.84, indicating strong support for the null hypothesis that global priming does not affect participants' mean typicality ratings. The failure to replicate this priming effect challenges existing support for the GLOMO sys model. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  8. Adaptation of Timing Behavior to a Regular Change in Criterion

    PubMed Central

    Sanabria, Federico; Oldenburg, Liliana

    2013-01-01

    This study examined how operant behavior adapted to an abrupt but regular change in the timing of reinforcement. Pigeons were trained on a fixed interval (FI) 15-s schedule of reinforcement during half of each experimental session, and on an FI 45-s (Experiment 1), FI 60-s (Experiment 2), or extinction schedule (Experiment 3) during the other half. FI performance was well characterized by a mixture of two gamma-shaped distributions of responses. When a longer FI schedule was in effect in the first half of the session (Experiment 1), a constant interference by the shorter FI was observed. When a shorter FI schedule was in effect in the first half of the session (Experiments 1, 2, and 3), the transition between schedules involved a decline in responding and a progressive rightward shift in the mode of the response distribution initially centered around the short FI. These findings are discussed in terms of the constraints they impose to quantitative models of timing, and in relation to the implications for information-based models of associative learning. PMID:23962672

  9. Association of Sleep Adequacy With More Healthful Food Choices and Positive Workplace Experiences Among Motor Freight Workers

    PubMed Central

    Quintiliani, Lisa M.; Yang, May H.; Ebbeling, Cara B.; Stoddard, Anne M.; Pereira, Lesley K.; Sorensen, Glorian

    2009-01-01

    Objectives. We assessed whether adequate sleep is linked to more healthful eating behaviors among motor freight workers and whether it mediates the effects of workplace experiences. Methods. Data were derived from a baseline survey and assessment of permanent employees at 8 trucking terminals. Bivariate and multivariate regression models were used to examine relationships between work environment, sleep adequacy, and dietary choices. Results. The sample (n = 542) was 83% White, with a mean age of 49 years and a mean body mass index of 30 kg/m2. Most of the participants were satisfied with their job (87.5%) and reported adequate sleep (51%); 30% reported job strain. In our first model, lack of job strain and greater supervisor support were significantly associated with adequate sleep. In our second model, educational level, age, and adequate sleep were significantly associated with at least 2 of the 3 healthful eating choices assessed (P < .05). However, work experiences were not significant predictors of healthful food choices when adequate sleep was included. Conclusions. Adequate sleep is associated with more healthful food choices and may mediate the effects of workplace experiences. Thus, workplace health programs should be responsive to workers' sleep patterns. PMID:19890169

  10. A fault injection experiment using the AIRLAB Diagnostic Emulation Facility

    NASA Technical Reports Server (NTRS)

    Baker, Robert; Mangum, Scott; Scheper, Charlotte

    1988-01-01

    The preparation for, conduct of, and results of a simulation based fault injection experiment conducted using the AIRLAB Diagnostic Emulation facilities is described. An objective of this experiment was to determine the effectiveness of the diagnostic self-test sequences used to uncover latent faults in a logic network providing the key fault tolerance features for a flight control computer. Another objective was to develop methods, tools, and techniques for conducting the experiment. More than 1600 faults were injected into a logic gate level model of the Data Communicator/Interstage (C/I). For each fault injected, diagnostic self-test sequences consisting of over 300 test vectors were supplied to the C/I model as inputs. For each test vector within a test sequence, the outputs from the C/I model were compared to the outputs of a fault free C/I. If the outputs differed, the fault was considered detectable for the given test vector. These results were then analyzed to determine the effectiveness of some test sequences. The results established coverage of selt-test diagnostics, identified areas in the C/I logic where the tests did not locate faults, and suggest fault latency reduction opportunities.

  11. Payload Planning for the International Space Station

    NASA Technical Reports Server (NTRS)

    Johnson, Tameka J.

    1995-01-01

    A review of the evolution of the International Space Station (ISS) was performed for the purpose of understanding the project objectives. It was requested than an analysis of the current Office of Space Access and Technology (OSAT) Partnership Utilization Plan (PUP) traffic model be completed to monitor the process through which the scientific experiments called payloads are manifested for flight to the ISS. A viewing analysis of the ISS was also proposed to identify the capability to observe the United States Laboratory (US LAB) during the assembly sequence. Observations of the Drop-Tower experiment and nondestructive testing procedures were also performed to maximize the intern's technical experience. Contributions were made to the meeting in which the 1996 OSAT or Code X PUP traffic model was generated using the software tool, Filemaker Pro. The current OSAT traffic model satisfies the requirement for manifesting and delivering the proposed payloads to station. The current viewing capability of station provides the ability to view the US LAB during station assembly sequence. The Drop Tower experiment successfully simulates the effect of microgravity and conveniently documents the results for later use. The non-destructive test proved effective in determining stress in various components tested.

  12. Predictive Modeling of Neuroblastoma Growth Dynamics in Xenograft Model After Bevacizumab Anti-VEGF Therapy.

    PubMed

    He, Yixuan; Kodali, Anita; Wallace, Dorothy I

    2018-06-14

    Neuroblastoma is the leading cause of cancer death in young children. Although treatment for neuroblastoma has improved, the 5-year survival rate of patients still remains less than half. Recent studies have indicated that bevacizumab, an anti-VEGF drug used in treatment of several other cancer types, may be effective for treating neuroblastoma as well. However, its effect on neuroblastoma has not been well characterized. While traditional experiments are costly and time-consuming, mathematical models are capable of simulating complex systems quickly and inexpensively. In this study, we present a model of vascular tumor growth of neuroblastoma IMR-32 that is complex enough to replicate experimental data across a range of tumor cell properties measured in a suite of in vitro and in vivo experiments. The model provides quantitative insight into tumor vasculature, predicting a linear relationship between vasculature and tumor volume. The tumor growth model was coupled with known pharmacokinetics and pharmacodynamics of the VEGF blocker bevacizumab to study its effect on neuroblastoma growth dynamics. The results of our model suggest that total administered bevacizumab concentration per week, as opposed to dosage regimen, is the major determining factor in tumor suppression. Our model also establishes an exponentially decreasing relationship between administered bevacizumab concentration and tumor growth rate.

  13. The making of the modern airport executive: Causal connections among key attributes in career development, compromise, and satisfaction in airport management

    NASA Astrophysics Data System (ADS)

    Byers, David Alan

    The purpose of this study was to identify specific career development attributes of contemporary senior-level airport executives and to evaluate the relationship of these attributes to the level of satisfaction airport executives have in their career choice. Attribute sets that were examined included early aviation interests, health factors, psychological factors, demographic factors, formal education, and other aviation-related experiences. A hypothesized causal model that expressed direct and indirect effects among these attributes relative to airport executives' career satisfaction was tested using sample data collected from 708 airport executives from general aviation and commercial service airport throughout the United States. Applying a multiple regression analysis strategy to the model, the overall results revealed that 16% of the variability in airport executives' career satisfaction scores was due to the collective influence of the six research attribute sets, this was significant. The results of the path analysis also indicated that four attribute sets (early aviation interests, health factors, formal education, and other aviation-related experiences) had respective direct significant effects on participants' career satisfaction. Early aviation interests, health factors, and demographic factors had additional indirect effects on career satisfaction; all were mediated by formal education attitude. These results were inconsistent with the hypothesized path model and a revised model was developed to reflect the sample data. The findings suggest that airport executives, as a group, are satisfied with their career choice. Early aviation interests appear to play an important role for influencing the career field selection phase of career development. The study also suggests health factors, formal education, and other aviation-related experiences such as flight training or military experience influence the compromise phase of career development. Each of these four factors had significant effects on career satisfaction. In addition to its applicability to airport executives, the study provides a generalized path model for investigating factors influencing the career development, compromise, and satisfaction process in other vocations.

  14. Crop Model Improvement Reduces the Uncertainty of the Response to Temperature of Multi-Model Ensembles

    NASA Technical Reports Server (NTRS)

    Maiorano, Andrea; Martre, Pierre; Asseng, Senthold; Ewert, Frank; Mueller, Christoph; Roetter, Reimund P.; Ruane, Alex C.; Semenov, Mikhail A.; Wallach, Daniel; Wang, Enli

    2016-01-01

    To improve climate change impact estimates and to quantify their uncertainty, multi-model ensembles (MMEs) have been suggested. Model improvements can improve the accuracy of simulations and reduce the uncertainty of climate change impact assessments. Furthermore, they can reduce the number of models needed in a MME. Herein, 15 wheat growth models of a larger MME were improved through re-parameterization and/or incorporating or modifying heat stress effects on phenology, leaf growth and senescence, biomass growth, and grain number and size using detailed field experimental data from the USDA Hot Serial Cereal experiment (calibration data set). Simulation results from before and after model improvement were then evaluated with independent field experiments from a CIMMYT worldwide field trial network (evaluation data set). Model improvements decreased the variation (10th to 90th model ensemble percentile range) of grain yields simulated by the MME on average by 39% in the calibration data set and by 26% in the independent evaluation data set for crops grown in mean seasonal temperatures greater than 24 C. MME mean squared error in simulating grain yield decreased by 37%. A reduction in MME uncertainty range by 27% increased MME prediction skills by 47%. Results suggest that the mean level of variation observed in field experiments and used as a benchmark can be reached with half the number of models in the MME. Improving crop models is therefore important to increase the certainty of model-based impact assessments and allow more practical, i.e. smaller MMEs to be used effectively.

  15. Combination of a higher-tier flow-through system and population modeling to assess the effects of time-variable exposure of isoproturon on the green algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata.

    PubMed

    Weber, Denis; Schaefer, Dieter; Dorgerloh, Michael; Bruns, Eric; Goerlitz, Gerhard; Hammel, Klaus; Preuss, Thomas G; Ratte, Hans Toni

    2012-04-01

    A flow-through system was developed to investigate the effects of time-variable exposure of pesticides on algae. A recently developed algae population model was used for simulations supported and verified by laboratory experiments. Flow-through studies with Desmodesmus subspicatus and Pseudokirchneriella subcapitata under time-variable exposure to isoproturon were performed, in which the exposure patterns were based on the results of FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) model calculations for typical exposure situations via runoff or drain flow. Different types of pulsed exposure events were realized, including a whole range of repeated pulsed and steep peaks as well as periods of constant exposure. Both species recovered quickly in terms of growth from short-term exposure and according to substance dissipation from the system. Even at a peak 10 times the maximum predicted environmental concentration of isoproturon, only transient effects occurred on algae populations. No modified sensitivity or reduced growth was observed after repeated exposure. Model predictions of algal growth in the flow-through tests agreed well with the experimental data. The experimental boundary conditions and the physiological properties of the algae were used as the only model input. No calibration or parameter fitting was necessary. The combination of the flow-through experiments with the algae population model was revealed to be a powerful tool for the assessment of pulsed exposure on algae. It allowed investigating the growth reduction and recovery potential of algae after complex exposure, which is not possible with standard laboratory experiments alone. The results of the combined approach confirm the beneficial use of population models as supporting tools in higher-tier risk assessments of pesticides. Copyright © 2012 SETAC.

  16. Role of negative emotion in communication about CO2 risks.

    PubMed

    Meijnders, A L; Midden, C J; Wilke, H A

    2001-10-01

    This article describes how the effectiveness of risk communication is determined by the interaction between emotional and informative elements. An experiment is described that examined the role of negative emotion in communication about CO2 risks. This experiment was based on the elaboration likelihood model and the related heuristic systematic model of attitude formation. The results indicated that inducing fear of CO2 risks leads to systematic processing of information about energy conservation as a risk-reducing strategy. In turn, this results in more favorable attitudes toward energy conservation if strong arguments are provided. Individual differences in concern seem to have similar effects.

  17. Prolonged effect of the stratospheric pathway in linking Barents-Kara Sea sea ice variability to the midlatitude circulation in a simplified model

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Wu, Yutian; Smith, Karen L.

    2018-01-01

    To better understand the dynamical mechanism that accounts for the observed lead-lag correlation between the early winter Barents-Kara Sea (BKS) sea ice variability and the later winter midlatitude circulation response, a series of experiments are conducted using a simplified atmospheric general circulation model with a prescribed idealized near-surface heating over the BKS. A prolonged effect is found in the idealized experiments following the near-surface heating and can be explicitly attributed to the stratospheric pathway and the long time scale in the stratosphere. The analysis of the Eliassen-Palm flux shows that, as a result of the imposed heating and linear constructive interference, anomalous upward propagating planetary-scale waves are excited and weaken the stratospheric polar vortex. This stratospheric response persists for approximately 1-2 months accompanied by downward migration to the troposphere and the surface. This downward migration largely amplifies and extends the low-level jet deceleration in the midlatitudes and cold air advection over central Asia. The idealized model experiments also suggest that the BKS region is the most effective in affecting the midlatitude circulation than other regions over the Arctic.

  18. Isozyme composition of lactate dehydrogenase of rat skeletal muscles after flight in Kosmos-690 biosatellite. [Effects of radiation on lactate dehydrogenase

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Petrova, N.V.

    1978-01-01

    Rats in a ground-based model experiment, in which all flight conditions with the exception of weightlessness and accelerations and intact animals maintained under vivarium conditions served as a control. On the 10th day of flight and of the ground-based model experiments, the rats were exposed to 800 rad radiation for 24 h. Samples of soleus and plantaris muscles were taken for examination on the 2d and 27th days after landing and termination of the ground-based model experiment. Intact animals were sacrificed on the same days as experimental ones. Samples of muscle tissue were frozen in dry ice and stored formore » several days at a temperature of -70/sup 0/ before they were studied. This investigation of isozyme spectrum of LDH of skeletal muscles of rats from the Kosmos-690 satellite indicates that the changes in proportion of isozyme fractions of LDH on the 2d day after the flight are due to the effects of weightlessness; subsequent changes (27th day) in correlation between LDH fraction activity are related to the effects of radiation.« less

  19. Using Film to Elucidate Leadership Effectiveness Models: Reflection on Authentic Learning Experiences

    ERIC Educational Resources Information Center

    Rajendran, Diana; Andrew, Martin

    2014-01-01

    This paper examines how students in a third year management unit at a university of technology in Australia evaluate the usefulness of film as a tool for developing a deeper understanding of the theoretical leadership effectiveness model developed by Robbins (1997). The study reviews the range of studies describing the use of films in teaching…

  20. Déjà vu experiences are rarely associated with pathological dissociation.

    PubMed

    Adachi, Naoto; Akanuma, Nozomi; Akanu, Nozomi; Adachi, Takuya; Takekawa, Yoshikazu; Adachi, Yasushi; Ito, Masumi; Ikeda, Hiroshi

    2008-05-01

    We investigated the relation between déjà vu and dissociative experiences in nonclinical subjects. In 227 adult volunteers, déjà vu and dissociative experiences were evaluated by means of the inventory of déjà vu experiences assessment and dissociative experiences scale (DES). Déjà vu experiences occurred in 162 (71.4%) individuals. In univariate correlation analysis, the frequency of déjà vu experiences, as well as 5 other inventory of déjà vu experiences assessment symptoms and age at the time of evaluation, correlated significantly with the DES score. After exclusion of intercorrelative effects using multiple regression analysis, déjà vu experiences did not remain in the model. The DES score was best correlated with a model that included age, jamais vu, depersonalization, and precognitive dreams. Two indices for pathological dissociation (DES-taxon and DES > or = 30) were not associated with déjà vu experiences. Our findings suggest that déjà vu experiences are unlikely to be core pathological dissociative experiences.

  1. The Effect of the Muller-Lyer Illusion on the Planning and Control of Manual Aiming Movements

    ERIC Educational Resources Information Center

    Mendoza, Jocelyn E.; Elliott, Digby; Meegan, Daniel V.; Lyons, James L.; Welsh, Timothy N.

    2006-01-01

    Two experiments used Muller-Lyer stimuli to test the predictions of the planning-control model (S. Glover, 2002) for aiming movements. In Experiment 1, participants aimed to stimuli that either remained the same or changed upon movement initiation. Experiment 2 was identical except that the duration of visual feedback for online control was…

  2. Validation of TGLF in C-Mod and DIII-D using machine learning and integrated modeling tools

    NASA Astrophysics Data System (ADS)

    Rodriguez-Fernandez, P.; White, Ae; Cao, Nm; Creely, Aj; Greenwald, Mj; Grierson, Ba; Howard, Nt; Meneghini, O.; Petty, Cc; Rice, Je; Sciortino, F.; Yuan, X.

    2017-10-01

    Predictive models for steady-state and perturbative transport are necessary to support burning plasma operations. A combination of machine learning algorithms and integrated modeling tools is used to validate TGLF in C-Mod and DIII-D. First, a new code suite, VITALS, is used to compare SAT1 and SAT0 models in C-Mod. VITALS exploits machine learning and optimization algorithms for the validation of transport codes. Unlike SAT0, the SAT1 saturation rule contains a model to capture cross-scale turbulence coupling. Results show that SAT1 agrees better with experiments, further confirming that multi-scale effects are needed to model heat transport in C-Mod L-modes. VITALS will next be used to analyze past data from DIII-D: L-mode ``Shortfall'' plasma and ECH swing experiments. A second code suite, PRIMA, allows for integrated modeling of the plasma response to Laser Blow-Off cold pulses. Preliminary results show that SAT1 qualitatively reproduces the propagation of cold pulses after LBO injections and SAT0 does not, indicating that cross-scale coupling effects play a role in the plasma response. PRIMA will be used to ``predict-first'' cold pulse experiments using the new LBO system at DIII-D, and analyze existing ECH heat pulse data. Work supported by DE-FC02-99ER54512, DE-FC02-04ER54698.

  3. The Effect of Ongoing Exposure Dynamics in Dose Response Relationships

    PubMed Central

    Pujol, Josep M.; Eisenberg, Joseph E.; Haas, Charles N.; Koopman, James S.

    2009-01-01

    Characterizing infectivity as a function of pathogen dose is integral to microbial risk assessment. Dose-response experiments usually administer doses to subjects at one time. Phenomenological models of the resulting data, such as the exponential and the Beta-Poisson models, ignore dose timing and assume independent risks from each pathogen. Real world exposure to pathogens, however, is a sequence of discrete events where concurrent or prior pathogen arrival affects the capacity of immune effectors to engage and kill newly arriving pathogens. We model immune effector and pathogen interactions during the period before infection becomes established in order to capture the dynamics generating dose timing effects. Model analysis reveals an inverse relationship between the time over which exposures accumulate and the risk of infection. Data from one time dose experiments will thus overestimate per pathogen infection risks of real world exposures. For instance, fitting our model to one time dosing data reveals a risk of 0.66 from 313 Cryptosporidium parvum pathogens. When the temporal exposure window is increased 100-fold using the same parameters fitted by our model to the one time dose data, the risk of infection is reduced to 0.09. Confirmation of this risk prediction requires data from experiments administering doses with different timings. Our model demonstrates that dose timing could markedly alter the risks generated by airborne versus fomite transmitted pathogens. PMID:19503605

  4. The Model Experiments and Finite Element Analysis on Deformation and Failure by Excavation of Grounds in Foregoing-roof Method

    NASA Astrophysics Data System (ADS)

    Sotokoba, Yasumasa; Okajima, Kenji; Iida, Toshiaki; Tanaka, Tadatsugu

    We propose the trenchless box culvert construction method to construct box culverts in small covering soil layers while keeping roads or tracks open. When we use this construction method, it is necessary to clarify deformation and shear failure by excavation of grounds. In order to investigate the soil behavior, model experiments and elasto-plactic finite element analysis were performed. In the model experiments, it was shown that the shear failure was developed from the end of the roof to the toe of the boundary surface. In the finite element analysis, a shear band effect was introduced. Comparing the observed shear bands in model experiments with computed maximum shear strain contours, it was found that the observed direction of the shear band could be simulated reasonably by the finite element analysis. We may say that the finite element method used in this study is useful tool for this construction method.

  5. Fatigue Damage of Collagenous Tissues: Experiment, Modeling and Simulation Studies

    PubMed Central

    Martin, Caitlin; Sun, Wei

    2017-01-01

    Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed. PMID:25955007

  6. Language and memory for object location.

    PubMed

    Gudde, Harmen B; Coventry, Kenny R; Engelhardt, Paul E

    2016-08-01

    In three experiments, we investigated the influence of two types of language on memory for object location: demonstratives (this, that) and possessives (my, your). Participants first read instructions containing demonstratives/possessives to place objects at different locations, and then had to recall those object locations (following object removal). Experiments 1 and 2 tested contrasting predictions of two possible accounts of language on object location memory: the Expectation Model (Coventry, Griffiths, & Hamilton, 2014) and the congruence account (Bonfiglioli, Finocchiaro, Gesierich, Rositani, & Vescovi, 2009). In Experiment 3, the role of attention allocation as a possible mechanism was investigated. Results across all three experiments show striking effects of language on object location memory, with the pattern of data supporting the Expectation Model. In this model, the expected location cued by language and the actual location are concatenated leading to (mis)memory for object location, consistent with models of predictive coding (Bar, 2009; Friston, 2003). Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Contamination control research activities for space optics in JAXA RANDD

    NASA Astrophysics Data System (ADS)

    Kimoto, Y.

    2017-11-01

    Contamination control research activities for space optics projects in JAXA R&D are described. More accurate contamination control techniques are requested because of intensified recent science mission requirements. One approach to control the contamination effects is analysis by software. JAXA has been developing a contamination analytical tool "J-SPICE" (Japanese Spacecraft Induced Contamination analysis software) as well as experiment facilities to improve the J-SPICE. A reflection model in J-SPICE has been experimentally verified and outgassing model data has been acquired by a facility. JAXA has developed a facility which could determine the influence of the contamination at a specific wavelength by combining a vacuum chamber with an I-R spectrometer and performed an experiment to inspect the effect of baking. Space material exposure experiment results reveal the actual thickness of the contamination layer in ISS orbit.

  8. Music performance and the perception of key.

    PubMed

    Thompson, W F; Cuddy, L L

    1997-02-01

    The effect of music performance on perceived key movement was examined. Listeners judged key movement in sequences presented without performance expression (mechanical) in Experiment 1 and with performance expression in Experiment 2. Modulation distance varied. Judgments corresponded to predictions based on the cycle of fifths and toroidal models of key relatedness, with the highest correspondence for performed versions with the toroidal model. In Experiment 3, listeners compared mechanical sequences with either performed sequences or modifications of performed sequences. Modifications preserved expressive differences between chords, but not between voices. Predictions from Experiments 1 and 2 held only for performed sequences, suggesting that differences between voices are informative of key movement. Experiment 4 confirmed that modifications did not disrupt musicality. Analyses of performances further suggested a link between performance expression and key.

  9. Effects of Clozapine and Alprazolam on Cognitive Deficits and Anxiety-Like Behaviors in a Ketamine-Induced Rat Model of Schizophrenia

    DTIC Science & Technology

    2005-01-01

    xii LIST OF TABLES Table 1. DSM-IV-TR Criteria for Schizophrenia (abbreviated) Table 2. Experimental Design Table 3. Experiment #1... Experimental Timeline Table 4. Experiment #2: Experimental Timeline Table 5. Experiment #1: Results of MANOVAs for Prepulse Inhibition Variables...rats. Please see Table 2 for a description of treatments and cell sizes for each experiment . Table 2. Experimental Design Ketamine (mg/kg

  10. The Effects of the MORE Wisdom Resources on Spousal Caregivers' Life Satisfaction: An Application of the Resilience Model.

    PubMed

    Kim, Seungyoun; Knight, Bob G

    2017-01-01

    Models of resilience suggest that psychosocial resources and their interactions facilitate resilience while experiencing life challenges of caregiving. The MORE wisdom resources (sense of Mastery, Openness to experience, Reflective attitude, and Emotion regulation) have been suggested as possible personal resources of resilience that predict positive health outcomes of caregivers. Applying a model of resilience, this study examined the direct and indirect effects of the three of the MORE wisdom resources (sense of Mastery, Openness to experience, and Emotion regulation) on caregiving spouses' life satisfaction and perceived physical health. Using data from the survey of Midlife in the United States, caregiving spouses (n = 114) and matched non-caregivers (n = 114) were included. We compared the direct and indirect effects of the wisdom resources on life satisfaction and physical health between the two groups. The simple mediation model proposed in 2008 by Preacher and Hayes revealed that openness to experience was directly associated with better life satisfaction among caregiving spouses. Sense of mastery and emotion regulation had indirect effects on life satisfaction through spousal support. The effects the wisdom resources on caregiving spouses' perceived physical health were not found. This study demonstrated that the three of the MORE wisdom resources are possible personal resilience factors influencing life satisfaction among caregiving spouses. Moreover, the study showed how spousal support mediates the relationship between the wisdom resources and life satisfaction. Interventions aiming to increase life satisfaction among caregiving spouses should focus on increasing both personal and environmental resources and strengthening the relationship of the caregiver and care recipient.

  11. A Kinetic Study of Microwave Start-up of Tokamak Plasmas

    NASA Astrophysics Data System (ADS)

    du Toit, E. J.; O'Brien, M. R.; Vann, R. G. L.

    2017-07-01

    A kinetic model for studying the time evolution of the distribution function for microwave startup is presented. The model for the distribution function is two dimensional in momentum space, but, for simplicity and rapid calculations, has no spatial dependence. Experiments on the Mega Amp Spherical Tokamak have shown that the plasma current is carried mainly by electrons with energies greater than 70 keV, and effects thought to be important in these experiments are included, i.e. particle sources, orbital losses, the loop voltage and microwave heating, with suitable volume averaging where necessary to give terms independent of spatial dimensions. The model predicts current carried by electrons with the same energies as inferred from the experiments, though the current drive efficiency is smaller.

  12. Beyond simple pessimism: effects of sadness and anger on social perception.

    PubMed

    Keltner, D; Ellsworth, P C; Edwards, K

    1993-05-01

    In keeping with cognitive appraisal models of emotion, it was hypothesized that sadness and anger would exert different influences on causal judgments. Two experiments provided initial support for this hypothesis. Sad Ss perceived situationally caused events as more likely (Experiment 1) and situational forces more responsible for an ambiguous event (Experiment 2) than angry Ss, who, in contrast, perceived events caused by humans as more likely and other people as more responsible. Experiments 3, 4, and 5 showed that the experience of these emotions, rather than their cognitive constituents, mediates these effects. The nonemotional exposure to situational or human agency information did not influence causal judgments (Experiment 3), whereas the induction of sadness and anger without explicit agency information did (Experiments 4 and 5). Discussion is focused on the influence of emotion on social judgment.

  13. Tunable vertical-cavity surface-emitting laser with feedback to implement a pulsed neural model. 2. High-frequency effects and optical coupling.

    PubMed

    Romariz, Alexandre R S; Wagner, Kelvin H

    2007-07-20

    The operation of an optoelectronic dynamic neural model implementation is extended to higher frequencies. A simplified model of thermal effects in vertical-cavity surface-emitting lasers correctly predicts the qualitative changes in the nonlinear mapping implementation with frequency. Experiments and simulations show the expected resonance properties of this model neuron, along with the possibility of other dynamic effects in addition to the ones observed in the original FitzHugh-Nagumo equations. Results of optical coupling between two similar pulsing artificial neurons are also presented.

  14. Refinement of a limit cycle oscillator model of the effects of light on the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Jewett, M. E.; Kronauer, R. E.; Brown, E. N. (Principal Investigator)

    1998-01-01

    In 1990, Kronauer proposed a mathematical model of the effects of light on the human circadian pacemaker. Although this model predicted many general features of the response of the human circadian pacemaker to light exposure, additional data now available enable us to refine the original model. We first refined the original model by incorporating the results of a dose response curve to light into the model's predicted relationship between light intensity and the strength of the drive onto the pacemaker. Data from three bright light phase resetting experiments were then used to refine the amplitude recovery characteristics of the model. Finally, the model was tested and further refined using data from an extensive phase resetting experiment in which a 3-cycle bright light stimulus was presented against a background of dim light. In order to describe the results of the four resetting experiments, the following major refinements to the original model were necessary: (i) the relationship between light intensity (I) and drive onto the pacemaker was reduced from I1/3 to I0.23 for light levels between 150 and 10,000 lux; (ii) the van der Pol oscillator from the original model was replaced with a higher-order limit cycle oscillator so that amplitude recovery is slower near the singularity and faster near the limit cycle; (iii) a direct effect of light on circadian period (tau x) was incorporated into the model such that as I increases, tau x decreases, which is in accordance with "Aschoff's rule". This refined model generates the following testable predictions: it should be difficult to enhance normal circadian amplitude via bright light; near the critical point of a type 0 phase response curve (PRC) the slope should be steeper than it is in a type 1 PRC; and circadian period measured during forced desynchrony should be directly affected by ambient light intensity.

  15. Dilatancy and compaction effects on the submerged granular column collapse

    NASA Astrophysics Data System (ADS)

    Wang, Chun; Wang, Yongqi; Peng, Chong; Meng, Xiannan

    2017-10-01

    The effects of dilatancy on the collapse dynamics of granular materials in air or in a liquid are studied experimentally and numerically. Experiments show that dilatancy has a critical effect on the collapse of granular columns in the presence of an ambient fluid. Two regimes of the collapse, one being quick and the other being slow, are observed from the experiments and the underlying reasons are analyzed. A two-fluid smoothed particle hydrodynamics model, based on the granular-fluid mixture theory and the critical state theory, is employed to investigate the complex interactions between the solid particles and the ambient water. It is found that dilatancy, resulting in large effective stress and large frictional coefficient between solid particles, helps form the slow regime. Small permeability, representing large inter-phase drag force, also retards the collapse significantly. The proposed numerical model is capable of reproducing these effects qualitatively.

  16. Project Physics Handbook 5, Models of the Atom.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Five experiments and 19 activities are presented in this Unit 5 handbook. The experiments are related to electrolysis, charge-to-mass ratio, elementary charge determination, photoelectric effects, and spectroscopic analyses. The activities are concerned with Dalton's theory, water electrolysis, periodic tables, single-electron plating, cloud…

  17. Predictors and Effects of Self-Objectification in Lesbians

    ERIC Educational Resources Information Center

    Haines, Megan E.; Erchull, Mindy J.; Liss, Miriam; Turner, Dixie L.; Nelson, Jaclyn A.; Ramsey, Laura R.; Hurt, Molly M.

    2008-01-01

    The majority of research on self-objectification has focused on heterosexual women's experiences. This study sought to examine experiences of self-objectification in lesbian women. A path model was developed to examine the relationships between participants' feminist self-identification, levels of internalized heterosexism, objectified body…

  18. Shooting Star Experiment

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Shooting Star Experiment (SSE) is designed to develop and demonstrate the technology required to focus the sun's energy and use the energy for inexpensive space Propulsion Research. Pictured is an engineering model (Pathfinder III) of the Shooting Star Experiment (SSE). This model was used to test and characterize the motion and deformation of the structure caused by thermal effects. In this photograph, alignment targets are being placed on the engineering model so that a theodolite (alignment telescope) could be used to accurately measure the deformation and deflections of the engineering model under extreme conditions, such as the coldness of deep space and the hotness of the sun as well as vacuum. This thermal vacuum test was performed at the X-Ray Calibration Facility because of the size of the test article and the capabilities of the facility to simulate in-orbit conditions

  19. Analysis of a DNA simulation model through hairpin melting experiments.

    PubMed

    Linak, Margaret C; Dorfman, Kevin D

    2010-09-28

    We compare the predictions of a two-bead Brownian dynamics simulation model to melting experiments of DNA hairpins with complementary AT or GC stems and noninteracting loops in buffer A. This system emphasizes the role of stacking and hydrogen bonding energies, which are characteristics of DNA, rather than backbone bending, stiffness, and excluded volume interactions, which are generic characteristics of semiflexible polymers. By comparing high throughput data on the open-close transition of various DNA hairpins to the corresponding simulation data, we (1) establish a suitable metric to compare the simulations to experiments, (2) find a conversion between the simulation and experimental temperatures, and (3) point out several limitations of the model, including the lack of G-quartets and cross stacking effects. Our approach and experimental data can be used to validate similar coarse-grained simulation models.

  20. Modeling of coherent ultrafast magneto-optical experiments: Light-induced molecular mean-field model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hinschberger, Y.; Hervieux, P.-A.

    2015-12-28

    We present calculations which aim to describe coherent ultrafast magneto-optical effects observed in time-resolved pump-probe experiments. Our approach is based on a nonlinear semi-classical Drude-Voigt model and is used to interpret experiments performed on nickel ferromagnetic thin film. Within this framework, a phenomenological light-induced coherent molecular mean-field depending on the polarizations of the pump and probe pulses is proposed whose microscopic origin is related to a spin-orbit coupling involving the electron spins of the material sample and the electric field of the laser pulses. Theoretical predictions are compared to available experimental data. The model successfully reproduces the observed experimental trendsmore » and gives meaningful insight into the understanding of magneto-optical rotation behavior in the ultrafast regime. Theoretical predictions for further experimental studies are also proposed.« less

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