Studying marine stratus with large eddy simulation

NASA Technical Reports Server (NTRS)

Moeng, Chin-Hoh

1990-01-01

Data sets from field experiments over the stratocumulus regime may include complications from larger scale variations, decoupled cloud layers, diurnal cycle, or entrainment instability, etc. On top of the already complicated turbulence-radiation-condensation processes within the cloud-topped boundary layer (CTBL), these complexities may sometimes make interpretation of the data sets difficult. To study these processes, a better understanding is needed of the basic processes involved in the prototype CTBL. For example, is cloud top radiative cooling the primary source of the turbulent kinetic energy (TKE) within the CTBL. Historically, laboratory measurements have played an important role in addressing the turbulence problems. The CTBL is a turbulent field which is probably impossible to generate in laboratories. Large eddy simulation (LES) is an alternative way of 'measuring' the turbulent structure under controlled environments, which allows the systematic examination of the basic physical processes involved. However, there are problems with the LES approach for the CTBL. The LES data need to be consistent with the observed data. The LES approach is discussed, and results are given which provide some insights into the simulated turbulent flow field. Problems with this approach for the CTBL and information from the FIRE experiment needed to justify the LES results are discussed.

Neurological Limitations of Aircraft Operations: Human Performance Implications (les Limitations neurologiques des operations aeriennes: les Consequences pour les performances des equipages).

DTIC Science & Technology

1996-04-01

Amniotic fluid Debris?* Young women Long bone fracture Fat * Any age Chronic intravenous drug users Talc* Any age Disseminated intravascular coagulapathy...maximal stress at which bone fracture occurs. This study demonstrated the usefulness of finite Results from centrifuge experiments element analysis for...Vine Street M/S 455 Philadelphia, PA 19102-1192, USA SUMMARY Exposure to Impact Acceleration (15). In these reports, fracture of the bones, dislocation

Exploring the Reality of Using Patient Experience Data to Provide Resident Feedback: A Qualitative Study of Attending Physician Perspectives

PubMed Central

Campbell, Steffanie; Goltz, Heather Honoré; Njue, Sarah; Dang, Bich Ngoc

2016-01-01

Introduction: Little is known about the attitudes of faculty and residents toward the use of patient experience data as a tool for providing resident feedback. The purpose of this study was to explore the attitudes of teaching faculty surrounding patient experience data and how those attitudes may influence the feedback given to trainees. Methods: From July 2013 to August 2013, we conducted in-depth, face-to-face, semistructured interviews with 9 attending physicians who precept residents in internal medicine at 2 continuity clinics (75% of eligible attendings). Interviews were coded using conventional content analysis. Results: Content analysis identified six potential barriers in using patient experience survey data to provide feedback to residents: 1) perceived inability of residents to learn or to incorporate feedback, 2) punitive nature of feedback, 3) lack of training in the delivery of actionable feedback, 4) lack of timeliness in the delivery of feedback, 5) unclear benefit of patient experience survey data as a tool for providing resident feedback, and 6) lack of individualized feedback. Conclusion: Programs may want to conduct an internal review on how patient experience data is incorporated into the resident feedback process and how, if at all, their faculty are trained to provide such feedback. PMID:27400180

Exploring the Reality of Using Patient Experience Data to Provide Resident Feedback: A Qualitative Study of Attending Physician Perspectives.

PubMed

Campbell, Steffanie; Goltz, Heather Honoré; Njue, Sarah; Dang, Bich Ngoc

2016-01-01

Little is known about the attitudes of faculty and residents toward the use of patient experience data as a tool for providing resident feedback. The purpose of this study was to explore the attitudes of teaching faculty surrounding patient experience data and how those attitudes may influence the feedback given to trainees. From July 2013 to August 2013, we conducted in-depth, face-to-face, semistructured interviews with 9 attending physicians who precept residents in internal medicine at 2 continuity clinics (75% of eligible attendings). Interviews were coded using conventional content analysis. Content analysis identified six potential barriers in using patient experience survey data to provide feedback to residents: 1) perceived inability of residents to learn or to incorporate feedback, 2) punitive nature of feedback, 3) lack of training in the delivery of actionable feedback, 4) lack of timeliness in the delivery of feedback, 5) unclear benefit of patient experience survey data as a tool for providing resident feedback, and 6) lack of individualized feedback. Programs may want to conduct an internal review on how patient experience data is incorporated into the resident feedback process and how, if at all, their faculty are trained to provide such feedback.

Artificial Neural Network Approaches in Guidance and Control (Les Reseaux Neuroniques Artificiels, Voie a Explorer dans le Domaine du Guidage et du Pilotage)

DTIC Science & Technology

1991-09-01

34 ofetworker eqmpleuoaorreation withbounethat basis vectors (Lawley & Maxwell , 1963). naletwk arn ungd eqatsi wthe boune E It is possible to think of the...passive sonar system IJCNN- signal Aerospace Technology Center, John 89 Washington proceedings Hopkins University) Analysis of hidden Succesful use of...establish the weighted equations and C3 applications interconnmctions of the net and electronic feedback based AUTH: A/CONNELL, JOHN C ., JR. CORP, Naval

Conception, elaboration et mise a l'essai d'un simulateur interactif permettant une approche modelisante: Application aux lois de la genetique mendelienne

NASA Astrophysics Data System (ADS)

Lasri, Abdel-Halim

Dans cette recherche-developpement, nous avons concu, developpe et mis a l'essai un simulateur interactif pour favoriser l'apprentissage des lois probabilistes impliqees dans la genetique mendelienne. Cet environnement informatise devra permettre aux etudiants de mener des experiences simulees, utilisant les statistiques et les probebilites comme outils mathematiques pour modeliser le phenomene de la transmission des caracteres hereditaires. L'approche didactique est essentiellement orientee vers l'utilisation des methodes quantitatives impliquees dans l'experimentation des facteurs hereditaires. En incorporant au simulateur le principe de la "Lunette cognitive" de Nonnon (1986), l'etudiant fut place dans une situation ou il a pu synchroniser la perception de la representation iconique (concrete) et symbolique (abstraite) des lois probabilistes de Mendel. A l'aide de cet environnement, nous avons amene l'etudiant a identifier le(s) caractere(s) hereditaire(s) des parents a croiser, a predire les frequences phenotypiques probables de la descendance issue du croisement, a observer les resultats statistiques et leur fluctuation au niveau de l'histogramme des frequences, a comparer ces resultats aux predictions anticipees, a interpreter les donnees et a selectionner en consequence d'autres experiences a realiser. Les etapes de l'approche inductive sont privilegiees du debut a la fin des activites proposees. L'elaboration, du simulateur et des documents d'accompagnement, a ete concue a partir d'une vingtaine de principes directeurs et d'un modele d'action. Ces principes directeurs et le modele d'action decoulent de considerations theoriques psychologiques, didactiques et technologiques. La recherche decrit la structure des differentes parties composant le simulateur. L'architecture de celui-ci est construite autour d'une unite centrale, la "Principale", dont les liens et les ramifications avec les autres unites confere a l'ensemble du simulateur sa souplesse et sa facilite d'utilisation. Le simulateur "Genetique", a l'etat de prototype, et la documentation qui lui est afferente ont ete soumis a deux mises a l'essai: l'une fonctionnelle, l'autre empirique. La mise a l'essai fonctionnelle, menee aupres d'un groupe d'enseignants experts, a permis d'identifier les lacunes du materiel elabore afin de lui apporter les reajustements qui s'imposaient. La mise a l'essai empirique, conduite par un groupe de onze (11) etudiants de niveau secondaire, avait pour but, d'une part, de tester la facilite d'utilisation du simulateur "Genetique" ainsi que les documents d'accompagnement et, d'autre part, de verifier si les participants retiraient des avantages pedagogiques de cet environnement. Trois techniques furent exploitees pour recolter les donnees de la mise a l'essai empirique. L'analyse des resultats a permis de faire un retour critique sur les productions concretes de cette recherche et d'apporter les modifications necessaires tant au simulateur qu'aux documents d'accompagnement. Cette analyse a permis egalement de conclure que notre simulateur interactif favorise une approche inductive permettant aux etudiants de s'approprier les lois probabilistes de Mendel. Enfin, la conclusion degage des pistes de recherches destinees aux etudes ulterieures, plus particulierement celles qui s'interessent a developper des simulateurs, afin d'integrer a ceux-ci des representations concretes et abstraites presentees en temps reel. Les disquettes du simulateur "Genetique" et les documents d'accompagnement sont annexes a la presente recherche.

Understanding Classroom Feedback Practices: A Study of New Zealand Student Experiences, Perceptions, and Emotional Responses

ERIC Educational Resources Information Center

Harris, Lois R.; Brown, Gavin T.; Harnett, Jennifer A.

2014-01-01

While feedback is a key factor for improving student learning, little is known about how students understand and experience feedback within the classroom. This study analysed 193 New Zealand primary and secondary students' survey responses alongside drawings of their understandings and experiences of feedback to examine how they experience,…

Large-eddy simulation of turbulent flow with a surface-mounted two-dimensional obstacle

NASA Technical Reports Server (NTRS)

Yang, Kyung-Soo; Ferziger, Joel H.

1993-01-01

In this paper, we perform a large eddy simulation (LES) of turbulent flow in a channel containing a two-dimensional obstacle on one wall using a dynamic subgrid-scale model (DSGSM) at Re = 3210, based on bulk velocity above the obstacle and obstacle height; the wall layers are fully resolved. The low Re enables us to perform a DNS (Case 1) against which to validate the LES results. The LES with the DSGSM is designated Case 2. In addition, an LES with the conventional fixed model constant (Case 3) is conducted to allow identification of improvements due to the DSGSM. We also include LES at Re = 82,000 (Case 4) using conventional Smagorinsky subgrid-scale model and a wall-layer model. The results will be compared with the experiment of Dimaczek et al.

Making sense of feedback experiences: a multi-school study of medical students' narratives.

PubMed

Urquhart, Lynn M; Rees, Charlotte E; Ker, Jean S

2014-02-01

Until recently, the perspective of students in the feedback process has been ignored, with strategies for improvement focusing on the tutor and feedback delivery. We employed an original narrative interviewing approach to explore how medical students make sense of their experiences of feedback. A qualitative design was adopted employing three individual and 10 group interviews to elicit narratives of feedback experiences from 53 medical students at three 5-year undergraduate programmes in the UK during 2011. Thematic analysis was undertaken of students' understandings of feedback and of their narratives of positive and negative experiences of feedback at medical school. In addition, thematic and discourse analysis of the linguistic and paralinguistic features of talk within the narratives was conducted. Students typically constructed feedback as a monologic process that happened 'to' them rather than 'with' them. They shared 352 distinct narratives of feedback experiences, which were rich in linguistic and paralinguistic features of talk. Through the analysis of the interplay between the 'whats' and 'hows' of student talk, i.e. emotion, pronominal and metaphoric talk and laughter, we were able to understand how students find meaning in their experiences. Students used laughter as a coping strategy, emotion talk as a means to convince the audience of the impact of feedback, pronominal and metaphoric talk to describe their relationship (often adversarial) with their feedback providers and to communicate feelings that they might otherwise struggle to articulate. This research extends current feedback literature by focusing on medical students' lived experiences of feedback and their emotional impact through narrative. We go on to discuss the educational implications of our findings and to make recommendations for improvement of the feedback process for students, tutors and for institutions. © 2014 John Wiley & Sons Ltd.

High-fidelity Simulation of Jet Noise from Rectangular Nozzles . [Large Eddy Simulation (LES) Model for Noise Reduction in Advanced Jet Engines and Automobiles

NASA Technical Reports Server (NTRS)

Sinha, Neeraj

2014-01-01

This Phase II project validated a state-of-the-art LES model, coupled with a Ffowcs Williams-Hawkings (FW-H) far-field acoustic solver, to support the development of advanced engine concepts. These concepts include innovative flow control strategies to attenuate jet noise emissions. The end-to-end LES/ FW-H noise prediction model was demonstrated and validated by applying it to rectangular nozzle designs with a high aspect ratio. The model also was validated against acoustic and flow-field data from a realistic jet-pylon experiment, thereby significantly advancing the state of the art for LES.

Fluctuations Magnetiques des Gaz D'electrons Bidimensionnels: Application AU Compose Supraconducteur LANTHANE(2-X) Strontium(x) Cuivre OXYGENE(4)

NASA Astrophysics Data System (ADS)

Benard, Pierre

Nous presentons une etude des fluctuations magnetiques de la phase normale de l'oxyde de cuivre supraconducteur La_{2-x}Sr _{x}CuO_4 . Le compose est modelise par le Hamiltonien de Hubbard bidimensionnel avec un terme de saut vers les deuxiemes voisins (modele tt'U). Le modele est etudie en utilisant l'approximation de la GRPA (Generalized Random Phase Approximation) et en incluant les effets de la renormalisation de l'interaction de Hubbard par les diagrammes de Brueckner-Kanamori. Dans l'approche presentee dans ce travail, les maximums du facteur de structure magnetique observes par les experiences de diffusion de neutrons sont associes aux anomalies 2k _{F} de reseau du facteur de structure des gaz d'electrons bidimensionnels sans interaction. Ces anomalies proviennent de la diffusion entre particules situees a des points de la surface de Fermi ou les vitesses de Fermi sont tangentes, et conduisent a des divergences dont la nature depend de la geometrie de la surface de Fermi au voisinage de ces points. Ces resultats sont ensuite appliques au modele tt'U, dont le modele de Hubbard usuel tU est un cas particulier. Dans la majorite des cas, les interactions ne determinent pas la position des maximums du facteur de structure. Le role de l'interaction est d'augmenter l'intensite des structures du facteur de structure magnetique associees a l'instabilite magnetique du systeme. Ces structures sont souvent deja presentes dans la partie imaginaire de la susceptibilite sans interaction. Le rapport d'intensite entre les maximums absolus et les autres structures du facteur de structure magnetique permet de determiner le rapport U_ {rn}/U_{c} qui mesure la proximite d'une instabilite magnetique. Le diagramme de phase est ensuite etudie afin de delimiter la plage de validite de l'approximation. Apres avoir discute des modes collectifs et de l'effet d'une partie imaginaire non-nulle de la self-energie, l'origine de l'echelle d'energie des fluctuations magnetiques est examinee. Il est ensuite demontre que le modele a trois bandes predit les memes resultats pour la position des structures du facteur de structure magnetique que le modele a une bande, dans la limite ou l'hybridation des orbitales des atomes d'oxygene des plans Cu-O_2 et l'amplitude de sauts vers les seconds voisins sont nulles. Il est de plus constate que l'effet de l'hybridation des orbitales des atomes d'oxygene est bien modelise par le terme de saut vers les seconds voisins. Meme si ils decrivent correctement le comportement qualitatif des maximums du facteur de structure magnetique, les modeles a trois bandes et a une bande ne permettent pas d'obtenir une position de ces structures conforme avec les mesures experimentales, si on suppose que la bande est rigide, c'est-a-dire que les parametres du Hamiltonien sont independants de la concentration de strontium. Ceci peut etre cause par la dependance des parametres du Hamiltonien sur la concentration de strontium. Finalement, les resultats sont compares avec les experiences de diffusion de neutrons et les autres theories, en particulier celles de Littlewood et al. (1993) et de Q. Si et al. (1993). La comparaison avec les resultats experimentaux pour le compose de lanthane suggere que le liquide de Fermi possede une surface de Fermi disjointe, et qu'il est situe pres d'une instabilite magnetique incommensurable.

A Hybrid Numerical Method for Turbulent Mixing Layers. Degree awarded by Case Western Reserve Univ.

NASA Technical Reports Server (NTRS)

Georgiadis, Nicholas J.

2001-01-01

A hybrid method has been developed for simulations of compressible turbulent mixing layers. Such mixing layers dominate the flows in exhaust systems of modern day aircraft and also those of hypersonic vehicles currently under development. The method configurations in which a dominant structural feature provides an unsteady mechanism to drive the turbulent development in the mixing layer. The hybrid method uses a Reynolds-averaged Navier-Stokes (RANS) procedure to calculate wall bounded regions entering a mixing section, and a Large Eddy Simulation (LES) procedure to calculate the mixing dominated regions. A numerical technique was developed to enable the use of the hybrid RANS-LES method on stretched, non-Cartesian grids. Closure for the RANS equations was obtained using the Cebeci-Smith algebraic turbulence model in conjunction with the wall-function approach of Ota and Goldberg. The wall-function approach enabled a continuous computational grid from the RANS regions to the LES region. The LES equations were closed using the Smagorinsky subgrid scale model. The hybrid RANS-LES method is applied to a benchmark compressible mixing layer experiment. Preliminary two dimensional calculations are used to investigate the effects of axial grid density and boundary conditions. Vortex shedding from the base region of a splitter plate separating the upstream flows was observed to eventually transition to turbulence. The location of the transition, however, was much further downstream than indicated by experiments. Actual LES calculations, performed in three spatial directions, also indicated vortex shedding, but the transition to turbulence was found to occur much closer to the beginning of the mixing section. which is in agreement with experimental observations. These calculations demonstrated that LES simulations must be performed in three dimensions. Comparisons of time-averaged axial velocities and turbulence intensities indicated reasonable agreement with experimental data.

Etude de la Production de Paires de Leptons dans les Interactions Proton-Beryllium a 450 GEV

NASA Astrophysics Data System (ADS)

Aubry, Pierre Rene Roger

L'experience HELIOS a fait une etude precise de la production des paires e^+e^-, mu^+mu^-, mu ^+mu^-+nu, et mu^+/- e^+/- dans les interactions p-Be a 450 GeV. Le detecteur comporte un spectrometre a electrons, un spectrometre a muons, et un ensemble de calorimetres qui peuvent mesurer les photons et l'energie manquante emportee par les neutrinos. Les paires de leptons sont observees dans la region cinematique ^1: eqalign {2/m_mu 6 GeV cr E_{e}&>2.8 GeV cr.25&

Activite locomotrice de souris isolees, de deux lignees consanguines, dans un environnement semi-naturel ou en cages d'elevage.

PubMed

Le Pape, G; Lassalle, J M

1979-10-01

Des enregistrements continus d'activité locomotrice ont été effectués sur des souris mâles isolées des lignées Balb/c et C57bl/6, vivant en cages d'élevage ou en milieu semi- naturel. Les résultats montrent que les différences entre ces deux situations ne sont pas perçues de la même façon par les animaux des deux lign'ees: alors qu'en cages d'élevage les souris des deux lignées experiment la même quantité totale d'activaté, en milieu semi-naturel les souris Balb/c sont plus actives que les C57bl/6. En outre, l≐s différences observées entre les lignées pour la repartition de l'activité au cours du nycthèmere s'inversent lorsque l'on passe d'une situation à l'autre. L'étude de la variabilité fait aparaître une dispersion plus grande des performances dans la lignée C57bl/6 en cages d'élevage, alors qu'en milieu semi-naturel la dispersion est plus chez Bal/c. Copyright © 1979. Published by Elsevier B.V.

Estimating the impact of internal climate variability on ice sheet model simulations

NASA Astrophysics Data System (ADS)

Tsai, C. Y.; Forest, C. E.; Pollard, D.

2016-12-01

Rising sea level threatens human societies and coastal habitats and melting ice sheets are a major contributor to sea level rise (SLR). Thus, understanding uncertainty of both forcing and variability within the climate system is essential for assessing long-term risk of SLR given their impact on ice sheet evolution. The predictability of polar climate is limited by uncertainties from the given forcing, the climate model response to this forcing, and the internal variability from feedbacks within the fully coupled climate system. Among those sources of uncertainty, the impact of internal climate variability on ice sheet changes has not yet been robustly assessed. Here we investigate how internal variability affects ice sheet projections using climate fields from two Community Earth System Model (CESM) large-ensemble (LE) experiments to force a three-dimensional ice sheet model. Each ensemble member in an LE experiment undergoes the same external forcings but with unique initial conditions. We find that for both LEs, 2m air temperature variability over Greenland ice sheet (GrIS) can lead to significantly different ice sheet responses. Our results show that the internal variability from two fully coupled CESM LEs can cause about 25 35 mm differences of GrIS's contribution to SLR in 2100 compared to present day (about 20% of the total change), and 100m differences of SLR in 2300. Moreover, only using ensemble-mean climate fields as the forcing in ice sheet model can significantly underestimate the melt of GrIS. As the Arctic region becomes warmer, the role of internal variability is critical given the complex nonlinear interactions between surface temperature and ice sheet. Our results demonstrate that internal variability from coupled atmosphere-ocean general circulation model can affect ice sheet simulations and the resulting sea-level projections. This study highlights an urgent need to reassess associated uncertainties of projecting ice sheet loss over the next few centuries to obtain robust estimates of the contribution of ice sheet melt to SLR.

Development of a Hybrid RANS/LES Method for Compressible Mixing Layer Simulations

NASA Technical Reports Server (NTRS)

Georgiadis, Nicholas J.; Alexander, J. Iwan D.; Reshotko, Eli

2001-01-01

A hybrid method has been developed for simulations of compressible turbulent mixing layers. Such mixing layers dominate the flows in exhaust systems of modem day aircraft and also those of hypersonic vehicles currently under development. The hybrid method uses a Reynolds-averaged Navier-Stokes (RANS) procedure to calculate wall bounded regions entering a mixing section, and a Large Eddy Simulation (LES) procedure to calculate the mixing dominated regions. A numerical technique was developed to enable the use of the hybrid RANS/LES method on stretched, non-Cartesian grids. The hybrid RANS/LES method is applied to a benchmark compressible mixing layer experiment. Preliminary two-dimensional calculations are used to investigate the effects of axial grid density and boundary conditions. Actual LES calculations, performed in three spatial directions, indicated an initial vortex shedding followed by rapid transition to turbulence, which is in agreement with experimental observations.

Large-Eddy Simulation (LES) of a Compressible Mixing Layer and the Significance of Inflow Turbulence

NASA Technical Reports Server (NTRS)

Mankbadi, Mina Reda; Georgiadis, Nicholas J.; Debonis, James R.

2017-01-01

In the context of Large Eddy Simulations (LES), the effects of inflow turbulence are investigated through the Synthetic Eddy Method (SEM). The growth rate of a turbulent compressible mixing layer corresponding to operating conditions of GeobelDutton Case 2 is investigated herein. The effects of spanwise width on the growth rate of the mixing layer is investigated such that spanwise width independence is reached. The error in neglecting inflow turbulence effects is quantified by comparing two methodologies: (1) Hybrid-RANS-LES methodology and (2) SEM-LES methodology. Best practices learned from Case 2 are developed herein and then applied to a higher convective mach number corresponding to Case 4 experiments of GeobelDutton.

A Comparison of Climate Feedback Strength between CO2 Doubling and LGM Experiments

NASA Astrophysics Data System (ADS)

Yoshimori, M.; Yokohata, T.; Abe-Ouchi, A.

2008-12-01

Studies of past climate potentially provide a constraint on the uncertainty of climate sensitivity, but previous studies warn against a simple scaling to the future. The climate sensitivity is determined by various feedback processes and they may vary with climate states and forcings. In this study, we investigate similarities and differences of feedbacks for a CO2 doubling, a last glacial maximum (LGM), and LGM greenhouse gas (GHG) forcing experiments, using an atmospheric general circulation model coupled to a slab ocean model. After computing the radiative forcing, the individual feedback strengths: water vapor, lapse rate, albedo, and cloud feedbacks, are evaluated explicitly. For this particular model, the difference in the climate sensitivity among experiments is attributed to the shortwave cloud feedback in which there is a tendency that it becomes weaker or even negative in the cooling experiments. No significant difference is found in the water vapor feedback between warming and cooling experiments by GHGs despite the nonlinear dependence of the Clausius-Clapeyron relation on temperature. The weaker water vapor feedback in the LGM experiment due to a relatively weaker tropical forcing is compensated by the stronger lapse rate feedback due to a relatively stronger extratropical forcing. A hypothesis is proposed which explains the asymmetric cloud response between warming and cooling experiments associated with a displacement of the region of mixed- phase clouds. The difference in the total feedback strength between experiments is, however, relatively small compared to the current intermodel spread, and does not necessarily preclude the use of LGM climate as a future constraint.

Description of the LASSO Alpha 1 Release

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

Gustafson, William I.; Vogelmann, Andrew M.; Cheng, Xiaoping

The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility began a pilot project in May 2015 to design a routine, high-resolution modeling capability to complement ARM’s extensive suite of measurements. This modeling capability has been named the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) project. The availability of LES simulations with concurrent observations will serve many purposes. LES helps bridge the scale gap between DOE ARM observations and models, and the use of routine LES adds value to observations. It provides a self-consistent representation of the atmosphere and a dynamical context for the observations. Further,more » it elucidates unobservable processes and properties. LASSO will generate a simulation library for researchers that enables statistical approaches beyond a single-case mentality. It will also provide tools necessary for modelers to reproduce the LES and conduct their own sensitivity experiments. Many different uses are envisioned for the combined LASSO LES and observational library. For an observationalist, LASSO can help inform instrument remote-sensing retrievals, conduct Observation System Simulation Experiments (OSSEs), and test implications of radar scan strategies or flight paths. For a theoretician, LASSO will help calculate estimates of fluxes and co-variability of values, and test relationships without having to run the model yourself. For a modeler, LASSO will help one know ahead of time which days have good forcing, have co-registered observations at high-resolution scales, and have simulation inputs and corresponding outputs to test parameterizations. Further details on the overall LASSO project are available at http://www.arm. gov/science/themes/lasso.« less

Can corrective feedback improve recognition memory?

PubMed

Kantner, Justin; Lindsay, D Stephen

2010-06-01

An understanding of the effects of corrective feedback on recognition memory can inform both recognition theory and memory training programs, but few published studies have investigated the issue. Although the evidence to date suggests that feedback does not improve recognition accuracy, few studies have directly examined its effect on sensitivity, and fewer have created conditions that facilitate a feedback advantage by encouraging controlled processing at test. In Experiment 1, null effects of feedback were observed following both deep and shallow encoding of categorized study lists. In Experiment 2, feedback robustly influenced response bias by allowing participants to discern highly uneven base rates of old and new items, but sensitivity remained unaffected. In Experiment 3, a false-memory procedure, feedback failed to attenuate false recognition of critical lures. In Experiment 4, participants were unable to use feedback to learn a simple category rule separating old items from new items, despite the fact that feedback was of substantial benefit in a nearly identical categorization task. The recognition system, despite a documented ability to utilize controlled strategic or inferential decision-making processes, appears largely impenetrable to a benefit of corrective feedback.

Application of Hierarchical Goal Analysis to the Halifax Class Frigate Operations Room: A Case Study

DTIC Science & Technology

2007-11-01

actuelle en fonction de son niveau de soutien pour ces diverses dépendances. Les auteurs prévoient que la même méthode peut être utilisée pour décrire...analysis. The focus of this paper is on the practice rather than the theory of HGA. Therefore, the next section contains only a brief summary of the...is based on Perceptual Control Theory [17], which posits that humans operate as perceptually driven, goal referenced, feedback systems, in that all

OPTICS (Operational Threat Integrated Corrective Spectacles) Production and Initial Human Factors Testing (Lunettes Optics (Lunettes Correctrices Integrees a L’equipment de protection Contre les Menaces Operationnelles) - Production et Essais Initiaux Relatifs Aux Facteurs Humains)

DTIC Science & Technology

2006-06-01

Integrated Corrective Spectacles (OPTICS) concepts . The aim of the OPTICS project is to develop an integrated set of corrective eyewear inserts that...months, three different OPTICS concepts were designed, developed and delivered to DCIEM. An iterative design approach with user feedback was utilized...Each concept employed a different approach for meeting the aims of the device; Concept 0 utilized a Commercial Off the Shelf sports-style

Numerical investigation of a helicopter combustion chamber using LES and tabulated chemistry

NASA Astrophysics Data System (ADS)

Auzillon, Pierre; Riber, Eléonore; Gicquel, Laurent Y. M.; Gicquel, Olivier; Darabiha, Nasser; Veynante, Denis; Fiorina, Benoît

2013-01-01

This article presents Large Eddy Simulations (LES) of a realistic aeronautical combustor device: the chamber CTA1 designed by TURBOMECA. Under nominal operating conditions, experiments show hot spots observed on the combustor walls, in the vicinity of the injectors. These high temperature regions disappear when modifying the fuel stream equivalence ratio. In order to account for detailed chemistry effects within LES, the numerical simulation uses the recently developed turbulent combustion model F-TACLES (Filtered TAbulated Chemistry for LES). The principle of this model is first to generate a lookup table where thermochemical variables are computed from a set of filtered laminar unstrained premixed flamelets. To model the interactions between the flame and the turbulence at the subgrid scale, a flame wrinkling analytical model is introduced and the Filtered Density Function (FDF) of the mixture fraction is modeled by a β function. Filtered thermochemical quantities are stored as a function of three coordinates: the filtered progress variable, the filtered mixture fraction and the mixture fraction subgrid scale variance. The chemical lookup table is then coupled with the LES using a mathematical formalism that ensures an accurate prediction of the flame dynamics. The numerical simulation of the CTA1 chamber with the F-TACLES turbulent combustion model reproduces fairly the temperature fields observed in experiments. In particular the influence of the fuel stream equivalence ratio on the flame position is well captured.

Surprising feedback improves later memory.

PubMed

Fazio, Lisa K; Marsh, Elizabeth J

2009-02-01

The hypercorrection effect is the finding that high-confidence errors are more likely to be corrected after feedback than are low-confidence errors (Butterfield & Metcalfe, 2001). In two experiments, we explored the idea that the hypercorrection effect results from increased attention to surprising feedback. In Experiment 1, participants were more likely to remember the appearance of the presented feedback when the feedback did not match expectations. In Experiment 2, we replicated this effect using more distinctive sources and also demonstrated the hypercorrection effect in this modified paradigm. Overall, participants better remembered both the surface features and the content of surprising feedback.

Effects of 3D virtual haptics force feedback on brand personality perception: the mediating role of physical presence in advergames.

PubMed

Jin, Seung-A Annie

2010-06-01

This study gauged the effects of force feedback in the Novint Falcon haptics system on the sensory and cognitive dimensions of a virtual test-driving experience. First, in order to explore the effects of tactile stimuli with force feedback on users' sensory experience, feelings of physical presence (the extent to which virtual physical objects are experienced as actual physical objects) were measured after participants used the haptics interface. Second, to evaluate the effects of force feedback on the cognitive dimension of consumers' virtual experience, this study investigated brand personality perception. The experiment utilized the Novint Falcon haptics controller to induce immersive virtual test-driving through tactile stimuli. The author designed a two-group (haptics stimuli with force feedback versus no force feedback) comparison experiment (N = 238) by manipulating the level of force feedback. Users in the force feedback condition were exposed to tactile stimuli involving various force feedback effects (e.g., terrain effects, acceleration, and lateral forces) while test-driving a rally car. In contrast, users in the control condition test-drove the rally car using the Novint Falcon but were not given any force feedback. Results of ANOVAs indicated that (a) users exposed to force feedback felt stronger physical presence than those in the no force feedback condition, and (b) users exposed to haptics stimuli with force feedback perceived the brand personality of the car to be more rugged than those in the control condition. Managerial implications of the study for product trial in the business world are discussed.

Model-Invariant Hybrid Computations of Separated Flows for RCA Standard Test Cases

NASA Technical Reports Server (NTRS)

Woodruff, Stephen

2016-01-01

NASA's Revolutionary Computational Aerosciences (RCA) subproject has identified several smooth-body separated flows as standard test cases to emphasize the challenge these flows present for computational methods and their importance to the aerospace community. Results of computations of two of these test cases, the NASA hump and the FAITH experiment, are presented. The computations were performed with the model-invariant hybrid LES-RANS formulation, implemented in the NASA code VULCAN-CFD. The model- invariant formulation employs gradual LES-RANS transitions and compensation for model variation to provide more accurate and efficient hybrid computations. Comparisons revealed that the LES-RANS transitions employed in these computations were sufficiently gradual that the compensating terms were unnecessary. Agreement with experiment was achieved only after reducing the turbulent viscosity to mitigate the effect of numerical dissipation. The stream-wise evolution of peak Reynolds shear stress was employed as a measure of turbulence dynamics in separated flows useful for evaluating computations.

Ecoulement et mise en structure de suspensions macroscopiques

NASA Astrophysics Data System (ADS)

Petit, L.

In this review, we report the various experimental studies performed on suspensions of solid particules in liquids, and concerning the rheological behaviour of such systems and the ordering of particules under the applied velocity fields. The number of materials which are flowing suspensions (reagents in chemical engineering, paints while spreading, blood flow, muds in oil reservoir) gave rise to a number of experimental studies, especially in the last twenty years. The results show a wide variety of behaviour, even for systems of intermediate concentration. In addition, even for identical systems, the results depend of the type of flow. Then, it is clear that, in addition of the standard parameters which are to be taken into account, it is necessary to consider the type of flow the suspension is submitted to. The flow influences the spatial distribution of the particules, leading to their ordering or migration. These ordering or motions influence the flow, and then, the rheological behaviour of the whole system. So, there is a feedback mechanism from the ordering to the flow, which explains the experimental observations. Nous reportons dans cette revue les différentes études expérimentales réalisées sur les suspensions de particules solides dans un liquide et qui concernent le comportement rhéologique de ces systèmes ainsi que les mouvements des particules sous l'effet des champs de vitesse imposés. Ces mouvements peuvent conduire soit à des mises en structure, ou encore à des migrations des particules. L'importance du nombre de matériaux qui se présentent sous forme de suspension et qui sont mis en écoulement (réactif en génie chimique, peintures lors de leur mise en place, écoulement sanguin, boues dans les forages pétroliers,...) a motivé un grand nombre de travaux expérimentaux plus fondamentaux sur le sujet, particulièrement dans les vingt dernières années. Les résultats correspondants montrent une très grande diversité des comportements même pour les systèmes moyennement concentrés. Bien plus, pour des systèmes identiques, les résultats dépendent du type d'écoulement imposé. Ceci montre clairement, qu'à côté des facteurs standards qui sont à prendre en compte pour caractériser le comportement de tels systèmes (concentration de la phase solide, taille des particules, interactions entre particules, effets de diffusion,...), il est nécessaire de tenir compte de la nature de l'écoulement auquel est soumise la suspension. Cet écoulement modifie la distribution spatiale des particules, soit directement, soit par l'intermédiaire de différents mécanismes tels que écoulements secondaires, diffusion. Ces effets se traduisent par une mise en ordre des particules, ou bien à des mouvements de migration. Les structures ou les mouvements ainsi créés agissent à leur tour sur les propriétés de l'écoulement, et de là, sur le comportement rhéologique de l'ensemble du système. Il existe ainsi un mécanisme de rétroaction de la structure sur l'écoulement qui permet d'expliquer les comportements observés expérimentalement.

Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

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

Yue, Qing; Kahn, Brian; Xiao, Heng

2013-08-16

Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared withmore » numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.« less

Descriptive Feedback: Student Voice in K-5 Classrooms

ERIC Educational Resources Information Center

Rodgers, Carol

2018-01-01

In this article, the author argues the imperative of critical dialogue between learners and teachers on learners' experiences in the classroom. This dialogical process is called "descriptive feedback"--feedback given by students to teachers on their (students') experiences as learners. Drawing on the literature on feedback, descriptive…

Biodynamic feedback training to assure learning partial load bearing on forearm crutches.

PubMed

Krause, Daniel; Wünnemann, Martin; Erlmann, Andre; Hölzchen, Timo; Mull, Melanie; Olivier, Norbert; Jöllenbeck, Thomas

2007-07-01

To examine how biodynamic feedback training affects the learning of prescribed partial load bearing (200N). Three pre-post experiments. Biomechanics laboratory in a German university. A volunteer sample of 98 uninjured subjects who had not used crutches recently. There were 24 subjects in experiment 1 (mean age, 23.2y); 64 in experiment 2 (mean age, 43.6y); and 10 in experiment 3 (mean age, 40.3y), parallelized by arm force. Video instruction and feedback training: In experiment 1, 2 varied instruction videos and reduced feedback frequency; in experiment 2, varied frequencies of changing tasks (contextual interference); and in experiment 3, feedback training (walking) and transfer (stair tasks). Vertical ground reaction force. Absolute error of practiced tasks was significantly reduced for all samples (P<.050). Varied contextual interference conditions did not significantly affect retention (P=.798) or transfer (P=.897). Positive transfer between tasks was significant in experiment 2 (P<.001) and was contrary to findings in experiment 3 (P=.071). Biodynamic feedback training is applicable for learning prescribed partial load bearing. The frequency of changing tasks is irrelevant. Despite some support for transfer effects, additional practice in climbing and descending stairs might be beneficial.

Interaction between light and superconductors

NASA Astrophysics Data System (ADS)

Gilabert, Alain

In the first part of this review article we resume briefly the fundamental aspect of the photon-superconductor interaction. The emphase is focused on the characteristic times and on the phenomenological models (the T*, the μ* models and the model of the kinetics equations) describing the out of equilibrium superconductivity. The experiments made on classical illuminated superconductors especially on tunnel junctions are then reported. In the second part we present the applied aspect of the photon-superconductor interaction. The interaction of the light with the high Tc superconductors is reviewed in the last part. Dans la première partie de cet article de revue, on résume brièvement 1'aspect fondamental de l'action des photons sur les supraconducteurs en s'attachant surtout à rappeler les différents temps caractéristiques de cette interaction et les modèles phénoménologiques (le modèle T*, le modèle μ*, le modèle des équations cinétiques) décrivant la supraconductivité hors équilibre. La seconde partie rappelle les expériences réalisées sur les supraconducteurs classiques illuminés et spécialement les jonctions tunnel ainsi que certaines applications de la supraconductivité hors équilibre comme les liens faibles controllables par des moyens optiques. La dernière partie est consacrée aux nouvelles expériences qui démarrent concernant l'action de la lumière sur les supraconducteurs à hautes températures critiques.

Reducing failures of working memory with performance feedback.

PubMed

Adam, Kirsten C S; Vogel, Edward K

2016-10-01

Fluctuations in attentional control can lead to failures of working memory (WM), in which the subject is no better than chance at reporting items from a recent display. In three experiments, we used a whole-report measure of visual WM to examine the impact of feedback on the rate of failures. In each experiment, subjects remembered an array of colored items across a blank delay, and then reported the identity of items using a whole-report procedure. In Experiment 1, we gave subjects simple feedback about the number of items they correctly identified at the end of each trial. In Experiment 2, we gave subjects additional information about the cumulative number of items correctly identified within each block. Finally, in Experiment 3, we gave subjects weighted feedback in which poor trials resulted in lost points and consistent successful performance received "streak" points. Surprisingly, simple feedback (Exp. 1) was ineffective at improving average performance or decreasing the rate of poor-performance trials. Simple cumulative feedback (Exp. 2) modestly decreased poor-performance trials (by 7 %). Weighted feedback produced the greatest benefits, decreasing the frequency of poor-performance trials by 28 % relative to baseline performance. This set of results demonstrates the usefulness of whole-report WM measures for investigating the effects of feedback on WM performance. Further, we showed that only a feedback structure that specifically discouraged lapses using negative feedback led to large reductions in WM failures.

Etude experimentale des excitations topologiques de l'effet Hall quantique a nu = 1 dans les heterostructures semiconductrices a double puits quantique

NASA Astrophysics Data System (ADS)

Charlebois, Serge

De nombreux travaux theoriques et experimentaux ont ete publies sur les excitations topologiques de gaz electroniques bidimensionnels (GE2D), appellees skyrmions, dans le regime de l'effet Hall quantique a remplissage unitaire. On attend des excitations semblables appellees bimerons dans les systemes formes de deux GE2D couples. Contrairement au cas des GE2D simples, aucune experience n'a, a notre connaissance, presente la mesure d'une propriete specifique aux bimerons. Nous presentons dans cette these des travaux experimentaux ayant pour objectif l'etude d'excitations topologiques dans les heterostructures a double puits quantique. Une manifestation attendue (les bimerons est la presence d'une anisotropie dans la conductivite a travers une constriction. Nous avons concu un dispositif original a point de contact a trois grilles non-coplanaires. Ce dispositif a trois grilles a la particularite de permettre la creation d'une constriction etroite dans le double GE2D tout en permettant l'equilibrage de la densite electronique entre les deux puits dans l'etroit canal de conduction. Nous avons fabrique ce dispositif de taille submicronique par electrolithographie sur des heterostructures a double puits. Les dispositifs ainsi fabriques ont ete etudies a basse temperature (0.3K) et ont montre un fonctionnement conforme aux attentes. Les travaux n'ont pas permis de mettre en evidence une anisotropie de transport revelatrice de l'existence de bimerons. Cette these est a notre connaissance la premiere etude experimentale visant la realisation de l'experience d'anisotropie de transport et est ainsi une contribution significative a l'avancement des connaissances dans ce domaine. Les travaux theoriques que nous presentons ont permis de montrer l'effet des excitations topologiques sur la capacite grille-GE2D du systeme. Ces travaux ouvrent la voie de la detection des bimerons par l'intermediaire de la mesure de la capacite grille-GE2D ou encore de la susceptibilite electrique du GE2D. Poursuivant cet objectif, nous avons concu, realise et teste un dispositif de mesure in situ de la capacite grille-GE2D d'une heterostructure. Nous avons egalement suggere d'autres methodes experimentales pour la mise en evidence des bimerons par le couplage de la texture de pseudospin a la capacite du GE2D.

Controle optique de qubits lies a des centres isoelectroniques d'azote dans le GaAs

NASA Astrophysics Data System (ADS)

Ethier-Majcher, Gabriel

Le traitement de l'information quantique est un domaine de recherche actuellement en pleine effervescence car il laisse entrevoir une revolution dans notre facon de traiter et d'echanger de l'information. D'une part, l'ordinateur quantique promet de resoudre des problemes comme la factorisation d'un polynome de facon beaucoup plus efficace qu'un ordinateur classique. D'autre part, les communications quantiques promettent l'echange d'information de facon fondamentalement inviolable. Afin de tirer pleinement profit de ces nouvelles technologies, il sera avantageux de construire des reseaux quantiques. Dans un tel reseau, des processeurs quantiques, les noeuds, seront connectes par des photons voyageant dans des fibres optiques. Les reseaux quantiques permettront de deployer les communications quantiques a grande echelle et de creer des super-ordinateurs quantiques. La realisation de reseaux quantiques necessitera des interfaces optiques pouvant echanger l'information de facon coherente entre un qubit (bit d'information quantique) et un photon. L'implementation de telles interfaces dans un systeme physique s'avere un important defi scientifique et technologique. Or, les systemes actuellement envisages a cette fin souffrent d'un faible couplage avec la lumiere ou encore de grandes inhomogeneites, constituant des obstacles a la realisation de reseaux a grande echelle. Dans cette these, le potentiel des centres isoelectroniques pour realiser des interfaces optiques est evalue. Deux types de qubits lies a des paires d'azote dans le GaAs sont consideres : les qubits excitoniques et les qubits de spin electronique, controlables par l'intermediaire d'excitons charges. Le controle optique complet des qubits excitoniques est demontre, ce qui constitue la premiere realisation du genre dans les centres isoelectroniques. L'observation d'excitons charges dans ce systeme, liant a la fois des trous lourds et des trous legers, laisse entrevoir de nouvelles possibilites afin de manipuler des spins electroniques. Les excitons et excitons charges lies aux paires d'azote sont etudies par la photoluminescence resolue spatialement. Le controle des qubits excitoniques est realisee a l'aide d'impulsions laser resonantes avec un etat excitonique et l'etat du qubit est lu par sa fluorescence en resonance. Une experience de rotations de Rabi est realisee pour demontrer un controle sur la population du qubit. Cette experience permet d'extraire un moment dipolaire moyen de 27 D pour l'exciton.

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

Gustafson, William I.; Vogelmann, Andrew M.; Cheng, Xiaoping

The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility began a pilot project in May 2015 to design a routine, high-resolution modeling capability to complement ARM’s extensive suite of measurements. This modeling capability has been named the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) project. The initial focus of LASSO is on shallow convection at the ARM Southern Great Plains (SGP) Climate Research Facility. The availability of LES simulations with concurrent observations will serve many purposes. LES helps bridge the scale gap between DOE ARM observations and models, and the use of routine LES addsmore » value to observations. It provides a self-consistent representation of the atmosphere and a dynamical context for the observations. Further, it elucidates unobservable processes and properties. LASSO will generate a simulation library for researchers that enables statistical approaches beyond a single-case mentality. It will also provide tools necessary for modelers to reproduce the LES and conduct their own sensitivity experiments. Many different uses are envisioned for the combined LASSO LES and observational library. For an observationalist, LASSO can help inform instrument remote sensing retrievals, conduct Observation System Simulation Experiments (OSSEs), and test implications of radar scan strategies or flight paths. For a theoretician, LASSO will help calculate estimates of fluxes and co-variability of values, and test relationships without having to run the model yourself. For a modeler, LASSO will help one know ahead of time which days have good forcing, have co-registered observations at high-resolution scales, and have simulation inputs and corresponding outputs to test parameterizations. Further details on the overall LASSO project are available at https://www.arm.gov/capabilities/modeling/lasso.« less

A resolvable subfilter-scale model specific to large-eddy simulation of under-resolved turbulence

NASA Astrophysics Data System (ADS)

Zhou, Yong; Brasseur, James G.; Juneja, Anurag

2001-09-01

Large-eddy simulation (LES) of boundary-layer flows has serious deficiencies near the surface when a viscous sublayer either does not exist (rough walls) or is not practical to resolve (high Reynolds numbers). In previous work, we have shown that the near-surface errors arise from the poor performance of algebraic subfilter-scale (SFS) models at the first several grid levels, where integral scales are necessarily under-resolved and the turbulence is highly anisotropic. In under-resolved turbulence, eddy viscosity and similarity SFS models create a spurious feedback loop between predicted resolved-scale (RS) velocity and modeled SFS acceleration, and are unable to simultaneously capture SFS acceleration and RS-SFS energy flux. To break the spurious coupling in a dynamically meaningful manner, we introduce a new modeling strategy in which the grid-resolved subfilter velocity is estimated from a separate dynamical equation containing the essential inertial interactions between SFS and RS velocity. This resolved SFS (RSFS) velocity is then used as a surrogate for the complete SFS velocity in the SFS stress tensor. We test the RSFS model by comparing LES of highly under-resolved anisotropic buoyancy-generated homogeneous turbulence with a corresponding direct numerical simulation (DNS). The new model successfully suppresses the spurious feedback loop between RS velocity and SFS acceleration, and greatly improves model predictions of the anisotropic structure of SFS acceleration and resolved velocity fields. Unlike algebraic models, the RSFS model accurately captures SFS acceleration intensity and RS-SFS energy flux, even during the nonequilibrium transient, and properly partitions SFS acceleration between SFS stress divergence and SFS pressure force.

The Effects of Active Videogame Feedback and Practicing Experience on Children's Physical Activity Intensity and Enjoyment.

PubMed

Chen, Han; Sun, Haichun

2017-08-01

The study aims to explore the effects of receiving active videogame (AVG) feedback and playing experience on individuals' moderate-to-vigorous physical activity (MVPA) and perceived enjoyment. This was a within-subject design study. The participants included 36 (n = 15 and 21 for boys and girls, respectively) fourth graders enrolled in a rural elementary school in southern Georgia area. The experiment lasted for 6 weeks with each week including three sessions. The participants were assigned in either front row (sensor feedback) or back row (no sensor feedback) during practice, which was alternated in different sessions. Two different dance games were played during the study with each game implemented for 3 weeks. The MVPA was measured with GT3X+ accelerometers. Physical activity (PA) enjoyment was assessed after the completion of the first two and last two sessions of each game. A repeated one-way ANOVA (analysis of variance) was used to examine the effects of AVG feedback and game on MVPA. A repeated one-way MANOVA (multivariate analysis of variance) was conducted for each game to examine the effects of experience and AVG feedback on enjoyment and MVPA. No effects of AVG feedback were found for MVPA or enjoyment (P > 0.05). The effects of experience on MVPA were found for Just Dance Kids 2014 with experience decreased MVPA (P < 0.05). Students who practiced dance AVG without receiving feedback still demonstrated positive affection and accumulated similar MVPA than when practicing while receiving feedback. Experience for certain dance games tends to decrease PA intensity.

LES of a ducted propeller with rotor and stator in crashback

NASA Astrophysics Data System (ADS)

Jang, Hyunchul; Mahesh, Krishnan

2012-11-01

A sliding interface method is developed for large eddy simulation (LES) of flow past ducted propellers with both rotor and stator. The method is developed for arbitrarily shaped unstructured elements on massively parallel computing platforms. Novel algorithms for searching sliding elements, interpolation at the sliding interface, and data structures for message passing are developed. We perform LES of flow past a ducted propeller with stator blades in the crashback mode of operation, where a marine vessel is quickly decelerated by rotating the propeller in reverse. The unsteady loads predicted by LES are in good agreement with experiments. A highly unsteady vortex ring is observed outside the duct. High pressure fluctuations are observed near the blade tips, which significantly contribute to the side-force. This work is supported by the United States Office of Naval Research.

Using Technology to Enhance Feedback to Student Teachers

ERIC Educational Resources Information Center

Gibson, Lenwood; Musti-Rao, Shobana

2016-01-01

The importance of effective and efficient feedback is paramount during the student teaching experience. This experience is a vital component of many teacher preparation programs. During these limited experiences, supervisors deliver performance feedback that is designed to improve the way student teachers implement evidence-based practices and/or…

New Postgraduate Student Experience and Engagement in Human Communication Studies

ERIC Educational Resources Information Center

Steele, Godfrey A.

2015-01-01

New postgraduate students' feedback on their learning offers insights into engagement. Student feedback to students and teachers can contribute to teacher feedback to students. When this happens, students can feel engaged or connected to their learning experiences. Adopting a more inclusive notion of feedback on learning, this paper explores the…

Social closeness and feedback modulate susceptibility to the framing effect

PubMed Central

Sip, Kamila E.; Smith, David V.; Porcelli, Anthony J.; Kar, Kohitij; Delgado, Mauricio R.

2014-01-01

Although, we often seek social feedback from others to help us make decisions, little is known about how social feedback affects decisions under risk, particularly from a close peer. We conducted two experiments using an established framing task to probe how decision making is modulated by social feedback valence (positive, negative) and the level of closeness with feedback provider (friend, confederate). Participants faced mathematically equivalent decisions framed as either an opportunity to keep (gain frame) or lose (loss frame) part of an initial endowment. Periodically, participants were provided with positive (e.g., “Nice!”) or negative (e.g., “Lame!”) feedback about their choices. Such feedback was provided by either a confederate (Experiment 1), or a gender-matched close friend (Experiment 2). As expected, the framing effect was observed in both experiments. Critically, an individual’s susceptibility to the framing effect was modulated by the valence of the social feedback, but only when the feedback provider was a close friend. This effect was reflected in the activation patterns of ventromedial prefrontal cortex and posterior cingulate cortex, regions involved in complex decision making. Taken together, these results highlight social closeness as an important factor in understanding the impact of social feedback on neural mechanisms of decision making. PMID:25074501

Improving Written Communication Through Minimal Feedback

PubMed Central

Traxler, Matthew J.; Gernsbacher, Morton Ann

2014-01-01

We propose that writers must form accurate representations of how their readers will interpret their texts to convey their ideas successfully. In two experiments, we investigated whether getting feedback from their readers helps writers form better representations of how their texts are interpreted. In our first experiment, one group of subjects (writers) wrote descriptions of a set of geometric figures; another group of subjects (readers) read those descriptions and used them to select the figures from sets of similar looking distractor figures. Half the writers received feedback on how well their readers selected the figures, and half the writers did not receive this feedback. Those writers who received feedback improved their descriptions more than those writers who did not receive feedback. In our second experiment, half the writers received two treatments of feedback on their descriptions of one set of figures, whereas the other half of the writers did not receive feedback. Then, all the writers described a new set of figures. Those writers who had previously received feedback wrote better new descriptions than did those writers who had never received feedback. We concluded that feedback – even this minimal form of feedback – helps writers to envision how readers interpret their texts. PMID:25520535

Comparing the effects of positive and negative feedback in information-integration category learning.

PubMed

Freedberg, Michael; Glass, Brian; Filoteo, J Vincent; Hazeltine, Eliot; Maddox, W Todd

2017-01-01

Categorical learning is dependent on feedback. Here, we compare how positive and negative feedback affect information-integration (II) category learning. Ashby and O'Brien (2007) demonstrated that both positive and negative feedback are required to solve II category problems when feedback was not guaranteed on each trial, and reported no differences between positive-only and negative-only feedback in terms of their effectiveness. We followed up on these findings and conducted 3 experiments in which participants completed 2,400 II categorization trials across three days under 1 of 3 conditions: positive feedback only (PFB), negative feedback only (NFB), or both types of feedback (CP; control partial). An adaptive algorithm controlled the amount of feedback given to each group so that feedback was nearly equated. Using different feedback control procedures, Experiments 1 and 2 demonstrated that participants in the NFB and CP group were able to engage II learning strategies, whereas the PFB group was not. Additionally, the NFB group was able to achieve significantly higher accuracy than the PFB group by Day 3. Experiment 3 revealed that these differences remained even when we equated the information received on feedback trials. Thus, negative feedback appears significantly more effective for learning II category structures. This suggests that the human implicit learning system may be capable of learning in the absence of positive feedback.

Improved memory for error feedback.

PubMed

Van der Borght, Liesbet; Schouppe, Nathalie; Notebaert, Wim

2016-11-01

Surprising feedback in a general knowledge test leads to an improvement in memory for both the surface features and the content of the feedback (Psychon Bull Rev 16:88-92, 2009). Based on the idea that in cognitive tasks, error is surprising (the orienting account, Cognition 111:275-279, 2009), we tested whether error feedback would be better remembered than correct feedback. Colored words were presented as feedback signals in a flanker task, where the color indicated the accuracy. Subsequently, these words were again presented during a recognition task (Experiment 1) or a lexical decision task (Experiments 2 and 3). In all experiments, memory was improved for words seen as error feedback. These results are compared to the attentional boost effect (J Exp Psychol Learn Mem Cogn 39:1223-12231, 2013) and related to the orienting account for post-error slowing (Cognition 111:275-279, 2009).

Comparing Student Learning Experiences of In-Text Commentary and Rubric-Articulated Feedback: Strategies for Formative Assessment

ERIC Educational Resources Information Center

Nordrum, Lene; Evans, Katherine; Gustafsson, Magnus

2013-01-01

This study compares students' experiences of two types of criteria-based assessment: in-text commentary and rubric-articulated feedback, in an assessment design combining the two feedback channels. The main aim is to use students' responses to shed light on how feedback strategies for formative assessment can be optimised. Following action…

Evaluative Feedback can Improve Deductive Reasoning

DTIC Science & Technology

2012-08-01

theories of reasoning explicitly permit evaluative feedback to modulate the way individuals reason (Braine & O’Brien, 1998; Oaksford & Chater, 2007...incorrect is to check their reasoning (Johnson-Laird, Girotto, & Legrenzi, 2004). If feedback influences the way people make deductions, theories of... theories of reasoning might account for improvements in performance due to evaluative feedback. Experiment 1: Sentential reasoning Experiment 1

Investigating Expectations and Experiences of Audio and Written Assignment Feedback in First-Year Undergraduate Students

ERIC Educational Resources Information Center

Fawcett, Hannah; Oldfield, Jeremy

2016-01-01

Previous research suggests that audio feedback may be an important mechanism for facilitating effective and timely assignment feedback. The present study examined expectations and experiences of audio and written feedback provided through "turnitin for iPad®" from students within the same cohort and assignment. The results showed that…

Motivation and attention: Incongruent effects of feedback on the processing of valence.

PubMed

Rothermund, Klaus

2003-09-01

Four experiments investigated the relation between outcome-related motivational states and processes of automatic attention allocation. Experiments 1-3 analyzed influences of feedback on evaluative decisions. Words of opposite valence to the feedback were processed faster, indicating that it is easier to allocate attention to the valence of an affectively incongruent word. Experiment 4 replicated the incongruent effect with interference effects of word valence in a grammatical-categorization task, indicating that the effect reflects automatic attentional capture. In all experiments, incongruent effects of feedback emerged only in a situation involving an attentional shift between words that differed in valence.

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features.

PubMed

Han, Chang-Hee; Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan; Im, Chang-Hwan

2016-01-01

It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features

PubMed Central

Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan

2016-01-01

It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training. PMID:27631005

Investigations of Flow Over a Hemisphere Using Numerical Simulations (Postprint)

DTIC Science & Technology

2015-06-22

ranging from missile defense, remote sensing , and imaging . An important aspect of these applications is determining the effective beam-on-target...Stokes (URANS), detached eddy simulation (DES), and hybrid RANS/LES. The numerical results were compared with the experiment conducted at Auburn...turret. Using the DES and hybrid RANS/LES turbulence models, Loci-Chem was able to capture the unsteady flow structures, such as the shear layer

The impact of parametrized convection on cloud feedback.

PubMed

Webb, Mark J; Lock, Adrian P; Bretherton, Christopher S; Bony, Sandrine; Cole, Jason N S; Idelkadi, Abderrahmane; Kang, Sarah M; Koshiro, Tsuyoshi; Kawai, Hideaki; Ogura, Tomoo; Roehrig, Romain; Shin, Yechul; Mauritsen, Thorsten; Sherwood, Steven C; Vial, Jessica; Watanabe, Masahiro; Woelfle, Matthew D; Zhao, Ming

2015-11-13

We investigate the sensitivity of cloud feedbacks to the use of convective parametrizations by repeating the CMIP5/CFMIP-2 AMIP/AMIP + 4K uniform sea surface temperature perturbation experiments with 10 climate models which have had their convective parametrizations turned off. Previous studies have suggested that differences between parametrized convection schemes are a leading source of inter-model spread in cloud feedbacks. We find however that 'ConvOff' models with convection switched off have a similar overall range of cloud feedbacks compared with the standard configurations. Furthermore, applying a simple bias correction method to allow for differences in present-day global cloud radiative effects substantially reduces the differences between the cloud feedbacks with and without parametrized convection in the individual models. We conclude that, while parametrized convection influences the strength of the cloud feedbacks substantially in some models, other processes must also contribute substantially to the overall inter-model spread. The positive shortwave cloud feedbacks seen in the models in subtropical regimes associated with shallow clouds are still present in the ConvOff experiments. Inter-model spread in shortwave cloud feedback increases slightly in regimes associated with trade cumulus in the ConvOff experiments but is quite similar in the most stable subtropical regimes associated with stratocumulus clouds. Inter-model spread in longwave cloud feedbacks in strongly precipitating regions of the tropics is substantially reduced in the ConvOff experiments however, indicating a considerable local contribution from differences in the details of convective parametrizations. In both standard and ConvOff experiments, models with less mid-level cloud and less moist static energy near the top of the boundary layer tend to have more positive tropical cloud feedbacks. The role of non-convective processes in contributing to inter-model spread in cloud feedback is discussed. © 2015 The Authors.

The impact of parametrized convection on cloud feedback

PubMed Central

Webb, Mark J.; Lock, Adrian P.; Bretherton, Christopher S.; Bony, Sandrine; Cole, Jason N. S.; Idelkadi, Abderrahmane; Kang, Sarah M.; Koshiro, Tsuyoshi; Kawai, Hideaki; Ogura, Tomoo; Roehrig, Romain; Shin, Yechul; Mauritsen, Thorsten; Sherwood, Steven C.; Vial, Jessica; Watanabe, Masahiro; Woelfle, Matthew D.; Zhao, Ming

2015-01-01

We investigate the sensitivity of cloud feedbacks to the use of convective parametrizations by repeating the CMIP5/CFMIP-2 AMIP/AMIP + 4K uniform sea surface temperature perturbation experiments with 10 climate models which have had their convective parametrizations turned off. Previous studies have suggested that differences between parametrized convection schemes are a leading source of inter-model spread in cloud feedbacks. We find however that ‘ConvOff’ models with convection switched off have a similar overall range of cloud feedbacks compared with the standard configurations. Furthermore, applying a simple bias correction method to allow for differences in present-day global cloud radiative effects substantially reduces the differences between the cloud feedbacks with and without parametrized convection in the individual models. We conclude that, while parametrized convection influences the strength of the cloud feedbacks substantially in some models, other processes must also contribute substantially to the overall inter-model spread. The positive shortwave cloud feedbacks seen in the models in subtropical regimes associated with shallow clouds are still present in the ConvOff experiments. Inter-model spread in shortwave cloud feedback increases slightly in regimes associated with trade cumulus in the ConvOff experiments but is quite similar in the most stable subtropical regimes associated with stratocumulus clouds. Inter-model spread in longwave cloud feedbacks in strongly precipitating regions of the tropics is substantially reduced in the ConvOff experiments however, indicating a considerable local contribution from differences in the details of convective parametrizations. In both standard and ConvOff experiments, models with less mid-level cloud and less moist static energy near the top of the boundary layer tend to have more positive tropical cloud feedbacks. The role of non-convective processes in contributing to inter-model spread in cloud feedback is discussed. PMID:26438278

A memory advantage for past-oriented over future-oriented performance feedback.

PubMed

Nash, Robert A; Winstone, Naomi E; Gregory, Samantha E A; Papps, Emily

2018-03-05

People frequently receive performance feedback that describes how well they achieved in the past, and how they could improve in future. In educational contexts, future-oriented (directive) feedback is often argued to be more valuable to learners than past-oriented (evaluative) feedback; critically, prior research led us to predict that it should also be better remembered. We tested this prediction in six experiments. Subjects read written feedback containing evaluative and directive comments, which supposedly related to essays they had previously written (Experiments 1-2), or to essays another person had written (Experiments 3-6). Subjects then tried to reproduce the feedback from memory after a short delay. In all six experiments, the data strongly revealed the opposite effect to the one we predicted: despite only small differences in wording, evaluative feedback was in fact recalled consistently better than directive feedback. Furthermore, even when adult subjects did recall directive feedback, they frequently misremembered it in an evaluative style. These findings appear at odds with the position that being oriented toward the future is advantageous to memory. They also raise important questions about the possible behavioral effects and generalizability of such biases, in terms of students' academic performance. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Large Eddy Simulation of High Reynolds Number Complex Flows

NASA Astrophysics Data System (ADS)

Verma, Aman

Marine configurations are subject to a variety of complex hydrodynamic phenomena affecting the overall performance of the vessel. The turbulent flow affects the hydrodynamic drag, propulsor performance and structural integrity, control-surface effectiveness, and acoustic signature of the marine vessel. Due to advances in massively parallel computers and numerical techniques, an unsteady numerical simulation methodology such as Large Eddy Simulation (LES) is well suited to study such complex turbulent flows whose Reynolds numbers (Re) are typically on the order of 10. 6. LES also promises increasedaccuracy over RANS based methods in predicting unsteady phenomena such as cavitation and noise production. This dissertation develops the capability to enable LES of high Re flows in complex geometries (e.g. a marine vessel) on unstructured grids and provide physical insight into the turbulent flow. LES is performed to investigate the geometry induced separated flow past a marine propeller attached to a hull, in an off-design condition called crashback. LES shows good quantitative agreement with experiments and provides a physical mechanism to explain the increase in side-force on the propeller blades below an advance ratio of J=-0.7. Fundamental developments in the dynamic subgrid-scale model for LES are pursued to improve the LES predictions, especially for complex flows on unstructured grids. A dynamic procedure is proposed to estimate a Lagrangian time scale based on a surrogate correlation without any adjustable parameter. The proposed model is applied to turbulent channel, cylinder and marine propeller flows and predicts improved results over other model variants due to a physically consistent Lagrangian time scale. A wall model is proposed for application to LES of high Reynolds number wall-bounded flows. The wall model is formulated as the minimization of a generalized constraint in the dynamic model for LES and applied to LES of turbulent channel flow at various Reynolds numbers up to Reτ=10000 and coarse grid resolutions to obtain significant improvement.

Feedback interventions and driving speed: A parametric and comparative analysis

PubMed Central

Houten, Ron Van; Nau, Paul A.

1983-01-01

Five experiments were conducted to assess the effects of several variables on the efficacy of feedback in reducing driving speed. Experiment 1 systematically varied the criterion used to define speeding, and results showed that the use of a lenient criterion (20 km/hr over the speed limit), which allowed for the posting of high percentages of drivers not speeding, was more effective in reducing speeding than the use of a stringent criterion (10 km/hr over the speed limit). In Experiment 2 an analysis revealed that posting feedback reduced speeding on a limited access highway and the effects persisted to some degree up to 6 km. Experiments 3 and 4 compared the effectiveness of an unmanned parked police vehicle (Experiment 3) and a police air patrol speeding program (Experiment 4) with the feedback sign and determined whether the presence of either of these enforcement variables could potentiate the efficacy of the sign. The results of both experiments demonstrated that although the two enforcement programs initially produced larger effects than the feedback sign, the magnitude of their effect attenuated over time. Experiment 5 compared the effectiveness of a traditional enforcement program with a warning program which included handing out a flier providing feedback on the number and types of accidents occuring on the road during the past year. This experiment demonstrated that the warning program produced a marked reduction in speeding and the traditional enforcement program did not. Furthermore, the warning program and a feedback sign together produced an even greater reduction in speeding than either alone. PMID:16795666

Exploring the large-scale structure of Taylor–Couette turbulence through Large-Eddy Simulations

NASA Astrophysics Data System (ADS)

Ostilla-Mónico, Rodolfo; Zhu, Xiaojue; Verzicco, Roberto

2018-04-01

Large eddy simulations (LES) of Taylor-Couette (TC) flow, the flow between two co-axial and independently rotating cylinders are performed in an attempt to explore the large-scale axially-pinned structures seen in experiments and simulations. Both static and dynamic LES models are used. The Reynolds number is kept fixed at Re = 3.4 · 104, and the radius ratio η = ri /ro is set to η = 0.909, limiting the effects of curvature and resulting in frictional Reynolds numbers of around Re τ ≈ 500. Four rotation ratios from Rot = ‑0.0909 to Rot = 0.3 are simulated. First, the LES of TC is benchmarked for different rotation ratios. Both the Smagorinsky model with a constant of cs = 0.1 and the dynamic model are found to produce reasonable results for no mean rotation and cyclonic rotation, but deviations increase for increasing rotation. This is attributed to the increasing anisotropic character of the fluctuations. Second, “over-damped” LES, i.e. LES with a large Smagorinsky constant is performed and is shown to reproduce some features of the large-scale structures, even when the near-wall region is not adequately modeled. This shows the potential for using over-damped LES for fast explorations of the parameter space where large-scale structures are found.

Analysis of unsteady reacting flows and impact of chemistry description in Large Eddy Simulations of side-dump ramjet combustors

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

Roux, A.; Gicquel, L.Y.M.; Staffelbach, G.

2010-01-15

Among all the undesired phenomena observed in ramjet combustors, combustion instabilities are of foremost importance and predicting them using Large Eddy Simulation (LES) is an active research field. While acoustics are naturally captured by compressible LES provided that the proper boundary conditions are applied, combustion/chemistry modelling remains a critical issue and its impact on numerical predictions must still be assessed for complex applications. To do so, two different ramjet LES's are compared here. The first simulation is based on a standard one-step chemistry known to over-estimate the laminar flame speed in fuel rich conditions. The second simulation uses the samemore » scheme but introduces a correction of reaction rates for rich flames to match a detailed mechanism provided by Peters (1993). Even though the two chemical schemes are very similar and very few points burn in rich regimes, distinct limit-cycles are obtained with LES depending on which scheme is used. Results obtained with the standard one-step chemistry exhibit high frequency self-sustained oscillations. Multiple flame fronts are stabilized in the vicinity of the shear layer developing at the exit of the air inlets. When compared to the experiment, the fitted one-step scheme yields better predictions than the standard scheme. With the fitted scheme, the flame is detached from the air inlets and stabilizes in the regions identified in the experiment (Ristori et al. (2005), Heid and Ristori (2003), Heid and Ristori (2005), Ristori et al. (1999)). LES and experiments exhibit all main low-frequency modes including the first longitudinal acoustic mode. The high frequencies excited with the standard scheme are damped with the fitted scheme. The chemical scheme is found, for this ramjet burner, to have a strong impact on the predicted stability: approximate chemical schemes even in a limited range of equivalence ratio can lead to the occurence of non-physical combustion oscillations. (author)« less

Explorer : des clés pour mieux comprendre la matière

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

Ellis, Jonathan R.

2011-02-14

Will the LHC upset theories of the infinitely small? Physicists would like the accelerator to shake the standard model. This theory of elementary particles and forces leaves many gray areas. The LHC and its experiments have been designed to enlighten them. [Le LHC va-t-il bouleverser les théories de l'infiniment petit ? Les physiciens aimeraient que l'accélérateur fasse trembler le modèle standard. Cette théorie des particules élémentaires et des forces laisse de nombreuses zones d'ombre. Le LHC et ses expériences ont été conçus pour les éclairer.

Zn influence on the plasticity of Cdo{0.96}Zn{0.04}Te

NASA Astrophysics Data System (ADS)

Imhoff, D.; Zozime, A.; Triboulet, R.

1991-11-01

Compression tests were performed on CdTe and Cd{0.96}Zn{0.04}Te to elucidate the mechanism through which Zn inhibits dislocation formation and motion during CdTe crystal growth, thus leading to a decreasing of the dislocation density. Uniaxial deformation experiments performed with CdTe and CdZnTe at constant strain rate within a wide temperature range (0. 14;T_m le T le 0.87;T_m,;T_m = 1 365; K), have revealed a strong hardening effect of Zn within the whole temperature range. They also showed in CdZnTe a Portevin Le Chatelier effect between 770 K and 920 K confirmed by static strain aging experiments. Critical resolved shear stress (C.R.S.S.) values at T = 195; K and static strain aging results with CdZnTe point to size effect as the dominant interaction between Zn and dislocations. Thermal activation parameters were estimated in both materials. La déformation plastique a été utilisée comme approche des mécanismes par lesquels le zinc entrave le mouvement des dislocations au cours du processus de croissance cristalline de CdTe massif, réduisant ainsi la densité de dislocations. Les expériences de compression uniaxiale à vitesse constante, réalisées dans CdTe et CdZnTe entre 0,14 T_f et 0,87 T_f ont montré que le zinc est responsable d'un fort durcissement sur tout le domaine de températures étudié. Les expériences de déformation dans CdZnTe ont mis en évidence un phénomène du type Portevin Le Chatelier entre 770 K et 920 K, confirmé par des expériences de vieillissement statique. Les valeurs de scission critique tau_c à 195 K et les résultats des expériences de vieillissement statique dans CdZnTe sont compatibles avec un effet de taille dominant pour les interactions Zndislocations. Les paramètres d'activation thermique ont été estimés dans les deux matériaux.

Teachers' Emotions and Test Feedback.

ERIC Educational Resources Information Center

Stough, Laura M.; Emmer, Edmund T.

1998-01-01

Investigates teachers thoughts about test-feedback sessions and their resulting emotions and strategies when delivering feedback to students. Explains that past experiences with feedback sessions, problem students, teachers beliefs about feedback processes, and their goals for providing feedback influence the teachers level of emotion; the…

CO2 acclimation impacts leaf isoprene emissions: evidence from past to future CO2 levels

NASA Astrophysics Data System (ADS)

de Boer, Hugo; van der Laan, Annick; Dekker, Stefan; Holzinger, Rupert

2017-04-01

Isoprene is emitted by many plant species as a side-product of photosynthesis. Once in the atmosphere, isoprene exhibits climate forcing through various feedback mechanisms. In order to quantify the climate feedbacks of biogenic isoprene emission it is crucial to establish how isoprene emissions are effected by plant acclimation to rising atmospheric CO2 levels. A promising development for modelling CO2-induced changes in isoprene emissions is the Leaf-Energetic-Status model (referred to as LES-model hereafter, see Harrison et al., 2013 and Morfopoulos et al., 2014). This model simulates isoprene emissions based on the hypothesis that isoprene biosynthesis depends on the imbalance between the photosynthetic electron supply of reducing power and the electron demands of carbon fixation. The energetic imbalance is critically related to the photosynthetic electron transport capacity (Jmax) and the maximum carboxylation capacity of Rubisco (Vcmax). Here we compare predictions of the LES-model with observed isoprene emission responses of Quercus robur (pedunculate oak) specimen that acclimated to CO2 growth conditions representative of the last glacial, the present and the end of this century (200, 400 and 800 ppm, respectively) for two growing seasons. These plants were grown in walk-in growth chambers with tight control of light, temperature, humidity and CO2 concentrations. Photosynthetic biochemical parameters Vcmax and Jmax were determined with a Licor LI-6400XT photosynthesis system. The relationship between photosynthesis and isoprene emissions was measured by coupling the photosynthesis system with a Proton-Transfer Reaction Time-of-Flight Mass Spectrometer. Our empirical results support the LES-model and show that the fractional allocation of carbon to isoprene biosynthesis is reduced in response to both short-term and long-term CO2 increases. In the short term, an increase in CO2 stimulates photosynthesis through an increase in the leaf interior CO2 concentration and marginally decreases isoprene production owing to an increase in the electron demand for carbon fixation. In the long-term, acclimation to rising CO2 growth conditions leads to down regulation of both Jmax and Vcmax, which modulates the stimulating effect of rising CO2 on photosynthesis. This CO2 effect is most pronounced between sub-ambient to present CO2. Our results highlight that the LES-model provides a suitable theoretical framework to model changes in leaf isoprene emissions related to biochemical acclimation to rising CO2. References Harrison, S. P. et al: Volatile isoprenoid emissions from plastid to planet, New Phytol., 197(1), 49-57, 2013. Morfopoulos, C. et al: A model of plant isoprene emission based on available reducing power captures responses to atmospheric CO2, New Phytol., 203(1), 125-139, 2014.

The study of the effects of sea-spray drops on the marine atmospheric boundary layer by direct numerical simulation

NASA Astrophysics Data System (ADS)

Druzhinin, O.; Troitskaya, Yu; Zilitinkevich, S.

2018-01-01

The detailed knowledge of turbulent exchange processes occurring in the atmospheric marine boundary layer are of primary importance for their correct parameterization in large-scale prognostic models. These processes are complicated, especially at sufficiently strong wind forcing conditions, by the presence of sea-spray drops which are torn off the crests of sufficiently steep surface waves by the wind gusts. Natural observations indicate that mass fraction of sea-spray drops increases with wind speed and their impact on the dynamics of the air in the vicinity of the sea surface can become quite significant. Field experiments, however, are limited by insufficient accuracy of the acquired data and are in general costly and difficult. Laboratory modeling presents another route to investigate the spray-mediated exchange processes in much more detail as compared to the natural experiments. However, laboratory measurements, contact as well as Particle Image Velocimetry (PIV) methods, also suffer from inability to resolve the dynamics of the near-surface air-flow, especially in the surface wave troughs. In this report, we present a first attempt to use Direct Numerical Simulation (DNS) as tool for investigation of the drops-mediated momentum, heat and moisture transfer in a turbulent, droplet-laden air flow over a wavy water surface. DNS is capable of resolving the details of the transfer processes and do not involve any closure assumptions typical of Large-Eddy and Reynolds Averaged Navier-Stokes (LES and RANS) simulations. Thus DNS provides a basis for improving parameterizations in LES and RANS closure models and further development of large-scale prognostic models. In particular, we discuss numerical results showing the details of the modification of the air flow velocity, temperature and relative humidity fields by multidisperse, evaporating drops. We use Eulerian-Lagrangian approach where the equations for the air-flow fields are solved in a Eulerian frame whereas the drops dymanics equations are solved in a Largangain frame. The effects of air flow and drops on the water surface wave are neglected. A point-force approximation is employed to model the feed-back contributions by the drops to the air momentum, heat and moisture transfer.

Large-Eddy Simulation of the Flat-plate Turbulent Boundary Layer at High Reynolds numbers

NASA Astrophysics Data System (ADS)

Inoue, Michio

The near-wall, subgrid-scale (SGS) model [Chung and Pullin, "Large-eddy simulation and wall-modeling of turbulent channel flow'', J. Fluid Mech. 631, 281--309 (2009)] is used to perform large-eddy simulations (LES) of the incompressible developing, smooth-wall, flat-plate turbulent boundary layer. In this model, the stretched-vortex, SGS closure is utilized in conjunction with a tailored, near-wall model designed to incorporate anisotropic vorticity scales in the presence of the wall. The composite SGS-wall model is presently incorporated into a computer code suitable for the LES of developing flat-plate boundary layers. This is then used to study several aspects of zero- and adverse-pressure gradient turbulent boundary layers. First, LES of the zero-pressure gradient turbulent boundary layer are performed at Reynolds numbers Retheta based on the free-stream velocity and the momentum thickness in the range Retheta = 103-1012. Results include the inverse skin friction coefficient, 2/Cf , velocity profiles, the shape factor H, the Karman "constant", and the Coles wake factor as functions of Re theta. Comparisons with some direct numerical simulation (DNS) and experiment are made, including turbulent intensity data from atmospheric-layer measurements at Retheta = O (106). At extremely large Retheta , the empirical Coles-Fernholz relation for skin-friction coefficient provides a reasonable representation of the LES predictions. While the present LES methodology cannot of itself probe the structure of the near-wall region, the present results show turbulence intensities that scale on the wall-friction velocity and on the Clauser length scale over almost all of the outer boundary layer. It is argued that the LES is suggestive of the asymptotic, infinite Reynolds-number limit for the smooth-wall turbulent boundary layer and different ways in which this limit can be approached are discussed. The maximum Retheta of the present simulations appears to be limited by machine precision and it is speculated, but not demonstrated, that even larger Retheta could be achieved with quad- or higher-precision arithmetic. Second, the time series velocity signals obtained from LES within the logarithmic region of the zero-pressure gradient turbulent boundary layer are used in combination with an empirical, predictive inner--outer wall model [Marusic et al., "Predictive model for wall-bounded turbulent flow'', Science 329, 193 (2010)] to calculate the statistics of the fluctuating streamwise velocity in the inner region of the zero-pressure gradient turbulent boundary layer. Results, including spectra and moments up to fourth order, are compared with equivalent predictions using experimental time series, as well as with direct experimental measurements at Reynolds numbers Retau based on the friction velocity and the boundary layer thickness, Retau = 7,300, 13,600 and 19,000. LES combined with the wall model are then used to extend the inner-layer predictions to Reynolds numbers Retau = 62,000, 100,000 and 200,000 that lie within a gap in log(Retau) space between laboratory measurements and surface-layer, atmospheric experiments. The present results support a log-like increase in the near-wall peak of the streamwise turbulence intensities with Retau and also provide a means of extending LES results at large Reynolds numbers to the near-wall region of wall-bounded turbulent flows. Finally, we apply the wall model to LES of a turbulent boundary layer subject to an adverse pressure gradient. Computed statistics are found to be consistent with recent experiments and some Reynolds number similarity is observed over a range of two orders of magnitude.

PReSaFe: A model of barriers and facilitators to patients providing feedback on experiences of safety.

PubMed

De Brún, Aoife; Heavey, Emily; Waring, Justin; Dawson, Pamela; Scott, Jason

2017-08-01

The importance of involving patients in reporting on safety is increasingly recognized. Whilst studies have identified barriers to clinician incident reporting, few have explored barriers and facilitators to patient reporting of safety experiences. This paper explores patient perspectives on providing feedback on safety experiences. Patients (n=28) were invited to take part in semi-structured interviews when given a survey about their experiences of safety following hospital discharge. Transcripts were thematically analysed using NVivo10. Patients were recruited from four hospitals in the UK. Three themes were identified as barriers and facilitators to patient involvement in providing feedback on their safety experiences. The first, cognitive-cultural, found that whilst safety was a priority for most, some felt the term was not relevant to them because safety was the "default" position, and/or because safety could not be disentangled from the overall experience of care. The structural-procedural theme indicated that reporting was facilitated when patients saw the process as straightforward, but that disinclination or perceived inability to provide feedback was a barrier. Finally, learning and change illustrated that perception of the impact of feedback could facilitate or inhibit reporting. When collecting patient feedback on experiences of safety, it is important to consider what may help or hinder this process, beyond the process alone. We present a staged model of prerequisite barriers and facilitators and hypothesize that each stage needs to be achieved for patients to provide feedback on safety experiences. Implications for collecting meaningful data on patients' safety experiences are considered. © 2016 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

Evaluer les competences communicatives (Evaluating Communicative Competence).

ERIC Educational Resources Information Center

Denis, Jackie; Van Thienen, Karine

1996-01-01

Two language teachers participating in an international seminar to develop methods for assessing second language communicative competence describe the experience, their reflections on its content, and an experiment in French writing instruction undertaken in Dutch-speaking Belgium. (MSE)

SOMAR-LES: A framework for multi-scale modeling of turbulent stratified oceanic flows

NASA Astrophysics Data System (ADS)

Chalamalla, Vamsi K.; Santilli, Edward; Scotti, Alberto; Jalali, Masoud; Sarkar, Sutanu

2017-12-01

A new multi-scale modeling technique, SOMAR-LES, is presented in this paper. Localized grid refinement gives SOMAR (the Stratified Ocean Model with Adaptive Resolution) access to small scales of the flow which are normally inaccessible to general circulation models (GCMs). SOMAR-LES drives a LES (Large Eddy Simulation) on SOMAR's finest grids, forced with large scale forcing from the coarser grids. Three-dimensional simulations of internal tide generation, propagation and scattering are performed to demonstrate this multi-scale modeling technique. In the case of internal tide generation at a two-dimensional bathymetry, SOMAR-LES is able to balance the baroclinic energy budget and accurately model turbulence losses at only 10% of the computational cost required by a non-adaptive solver running at SOMAR-LES's fine grid resolution. This relative cost is significantly reduced in situations with intermittent turbulence or where the location of the turbulence is not known a priori because SOMAR-LES does not require persistent, global, high resolution. To illustrate this point, we consider a three-dimensional bathymetry with grids adaptively refined along the tidally generated internal waves to capture remote mixing in regions of wave focusing. The computational cost in this case is found to be nearly 25 times smaller than that of a non-adaptive solver at comparable resolution. In the final test case, we consider the scattering of a mode-1 internal wave at an isolated two-dimensional and three-dimensional topography, and we compare the results with Legg (2014) numerical experiments. We find good agreement with theoretical estimates. SOMAR-LES is less dissipative than the closure scheme employed by Legg (2014) near the bathymetry. Depending on the flow configuration and resolution employed, a reduction of more than an order of magnitude in computational costs is expected, relative to traditional existing solvers.

Evaluation d'une approche pedagogique respectant les facons d'apprendre des filles en sciences et en TIC en 9e annee au Nouveau-Brunswick

NASA Astrophysics Data System (ADS)

Lirette-Pitre, Nicole T.

2009-07-01

La reussite scolaire des filles les amene de plus en plus a poursuivre une formation postsecondaire et a exercer des professions qui demandent un haut niveau de connaissances et d'expertise scientifique. Toutefois, les filles demeurent toujours tres peu nombreuses a envisager une carriere en sciences (chimie et physique), en ingenierie ou en TIC (technologie d'information et de la communication), soit une carriere reliee a la nouvelle economie. Pour plusieurs filles, les sciences et les TIC ne sont pas des matieres scolaires qu'elles trouvent interessantes meme si elles y reussissent tres bien. Ces filles admettent que leurs experiences d'apprentissage en sciences et en TIC ne leur ont pas permis de developper un interet ni de se sentir confiante en leurs habiletes a reussir dans ces matieres. Par consequent, peu de filles choisissent de poursuivre leurs etudes postsecondaires dans ces disciplines. La theorie sociocognitive du choix carriere a ete choisie comme modele theorique pour mieux comprendre quelles variables entrent en jeu lorsque les filles choisissent leur carriere. Notre etude a pour objet la conception et l'evaluation de l'efficacite d'un materiel pedagogique concu specifiquement pour ameliorer les experiences d'apprentissage en sciences et en TIC des filles de 9e annee au Nouveau-Brunswick. L'approche pedagogique privilegiee dans notre materiel a mis en oeuvre des strategies pedagogiques issues des meilleures pratiques que nous avons identifiees et qui visaient particulierement l'augmentation du sentiment d'auto-efficacite et de l'interet des filles pour ces disciplines. Ce materiel disponible par Internet a l'adresse http://www.umoncton.ca/lirettn/scientic est directement en lien avec le programme d'etudes en sciences de la nature de 9e annee du Nouveau-Brunswick. L'evaluation de l'efficacite de notre materiel pedagogique a ete faite selon deux grandes etapes methodologiques: 1) l'evaluation de l'utilisabilite et de la convivialite du materiel et 2) l'evaluation de l'effet du materiel en fonction de diverses variables reliees a l'interet et au sentiment d'auto-efficacite des filles en sciences et en TIC. Cette recherche s'est inscrite dans un paradigme pragmatique de recherche. Le pragmatisme a guide nos choix en ce qui a trait au modele de recherche et des techniques utilisees. Cette recherche a associe a la fois des techniques qualitatives et quantitatives, particulierement en ce qui concerne la collecte et l'analyse de donnees. Les donnees recueillies dans la premiere etape de l'evaluation de l'utilisabilite et de la convivialite du materiel par les enseignantes et les enseignants de sciences et les filles ont revele que le materiel concu est tres utilisable et convivial. Toutefois quelques petites ameliorations seront apportees a une version subsequente afin de faciliter davantage la navigation. Quant a l'evaluation des effets du materiel concu sur les variables reliees au sentiment d'auto-efficacite et aux interets lors de l'etape quasi experimentale, nos donnees qualitatives ont indique que ce materiel a eu des effets positifs sur le sentiment d'auto-efficacite et sur les interets des filles qui l'ont utilise. Toutefois, nos donnees quantitatives n'ont pas permis d'inferer un lien causal direct entre l'utilisation du materiel et l'augmentation du sentiment d'auto-efficacite et des interets des filles en sciences et en TIC. A la lumiere des resultats obtenus, nous avons conclu que le materiel a eu les effets escomptes. Donc, nous recommandons la creation et l'utilisation de materiel de ce genre dans toutes les classes de sciences de la 6e annee a la 12e annee au Nouveau-Brunswick.

Commutation assistée, des machines à courant continu

NASA Astrophysics Data System (ADS)

Goyet, R.; Benalla, H.

1994-12-01

The paper presents an experiment of DC machine (135V, 60A, 8kW) working without commutating poles. These have the usual function of implementing the commutation of sections as they pass trough the neutral line. It is a question of reversing the section current in front of the brushes. Commutating poles are generally bulky and increase perceptibly heaviness of the machine (of 1/5about). In the following experiment they are suppressed and commutation is carried out from the outside of the machine owing to an electronic device. Working of this electronic assistance has been described in a previous paper. Here, in this second paper, two different devices are implemented until three quarters of nominal values of the machine ; accurate control of the devices is made easier by means of a computer. Experiment has been implemented without any spark under the brushes, it confirms the feasibility of a new way of commutation for DC machines. These devices do not make yet an industrial way of suppressing commutating poles. On the other hand they lead to an original point of view about commutation phenomena. They set a new process using both the cutting off capability of brushes and the accurate adjustements of power electronics. Nous présentons ici une expérimentation d'une machine à courant continu de puissance 8 kW (135 V, 60 A) fonctionnant sans pôles auxiliaires. Rappelons que ces derniers ont pour fonction habituelle d'assurer la commutation des sections à leur passage sur la ligne neutre. Il s'agit d'inverser le courant dans la section lorsqu'elle passe devant les balais. Les pôles auxiliaires sont en général encombrants et augmentent sensiblement le poids de la machine (de 1/5 environ). Dans l'expérience présentée ici ils sont supprimés et la commutation est réalisée à l'extérieur de la machine grâce à un dispositif électronique appelé ll d'assistance gg. Dans un précédent article [1] nous avons donné le principe de fonctionnement de cette assistance. Dans ce deuxième article nous présentons les résultats obtenus sur une machine à l'aide de deux dispositifs électroniques différents pilotés par ordinateur. Cette machine a fonctionné, sans génération d'arc, à trois quarts de sa puissance nominale. L'expérience confirme les possibilités de la commutation assistée par électronique. Les dispositifs utilisés ne constituent pas encore une solution industriellement viable en remplacement du pôle auxiliaire. Ils permettent par contre d'appréhender de façon originale les phénomènes de commutation. Il s'agit d'un procédé nouveau, utilisant à la fois le pouvoir de coupure des balais et les possibilités de réglage fin de l'électronique de puissance.

Impedance de surface dans les supraconducteurs quasi-bidimensionnels

NASA Astrophysics Data System (ADS)

Achkir, Driss Brice

Ce travail a caractere experimental et theorique vise l'etude de l'etat supraconducteur de trois familles de composes: les supraconducteurs conventionnels, les organiques et les cuprates YBCO. Pour ce faire, nous avons utilise une technique hyperfrequence, a savoir la mesure d'impedance de surface en fonction de la temperature et du champ magnetique. Dans les supraconducteurs conventionnels, nous avons mesure pour la premiere fois le pic de "coherence" dans la partie reelle de la conductivite. Bien que predit par la theorie BCS, ce pic n'avait pas ete clairement observe en raison de difficultes techniques liees a ce type d'experience. D'autre part, la theorie d'Eliashberg appliquee a la partie reelle de la conductivite du niobium nous a revele l'importance des mesures hyperfrequences pour mieux extraire la partie basse frequence de la densite spectrale alphasp2F(omega). Cette possibilite est attrayante puisque c'est precisement la region de frequences de alphasp2F(omega) ou les donnees d'effet tunnel sont imprecises. Les resultats obtenus sur la longueur de penetration dans les organiques et les cuprates ont permis de montrer que le gap presente des lignes de zeros au niveau de Fermi ou qu'il est, a tout le moins, fortement anisotrope. En effet, la dependance en temperature de la longueur de penetration dans les cristaux purs est lineaire a basse temperature et elle devient quadratique dans les cristaux dopes. Pour le cas des supraconducteurs organiques quasi-bidimensionnels (Et)sb2X, nous avons aussi observe un maximum sur la partie reelle de la conductivite qui n'a rien a voir avec un pic de coherence. Pour ces composes, nous avons effectue une des toutes premieres etudes des fluctuations supraconductrices en temperature et en champ magnetique. Nous montrons que la paraconductivite sigmasp' due aux fluctuations presente un comportement de type Aslamazov-Larkin de nature tridimensionnelle. Ces mesures sont appuyees par les resultats theoriques d'un modele Ginzburg-Landau dynamique que nous avons developpe. De plus, a partir de l'analyse des fluctuations, nous avons pu identifier le champ critique pour la transition resistive en champ et ainsi en deduire la transition de fonte du reseau de vortex dans le (Et)sb2Cu(SCN)sb2.

Effects of postidentification feedback on eyewitness identification and nonidentification confidence.

PubMed

Semmler, Carolyn; Brewer, Neil; Wells, Gary L

2004-04-01

Two experiments investigated new dimensions of the effect of confirming feedback on eyewitness identification confidence using target-absent and target-present lineups and (previously unused) unbiased witness instructions (i.e., "offender not present" option highlighted). In Experiment 1, participants viewed a crime video and were later asked to try to identify the thief from an 8-person target-absent photo array. Feedback inflated witness confidence for both mistaken identifications and correct lineup rejections. With target-present lineups in Experiment 2, feedback inflated confidence for correct and mistaken identifications and lineup rejections. Although feedback had no influence on the confidence-accuracy correlation, it produced clear overconfidence. Confidence inflation varied with the confidence measure reference point (i.e., retrospective vs. current confidence) and identification response latency.

Simulation and Feedback in Health Education: A Mixed Methods Study Comparing Three Simulation Modalities.

PubMed

Tait, Lauren; Lee, Kenneth; Rasiah, Rohan; Cooper, Joyce M; Ling, Tristan; Geelan, Benjamin; Bindoff, Ivan

2018-05-03

Background . There are numerous approaches to simulating a patient encounter in pharmacy education. However, little direct comparison between these approaches has been undertaken. Our objective was to investigate student experiences, satisfaction, and feedback preferences between three scenario simulation modalities (paper-, actor-, and computer-based). Methods . We conducted a mixed methods study with randomized cross-over of simulation modalities on final-year Australian graduate-entry Master of Pharmacy students. Participants completed case-based scenarios within each of three simulation modalities, with feedback provided at the completion of each scenario in a format corresponding to each simulation modality. A post-simulation questionnaire collected qualitative and quantitative responses pertaining to participant satisfaction, experiences, and feedback preferences. Results . Participants reported similar levels satisfaction across all three modalities. However, each modality resulted in unique positive and negative experiences, such as student disengagement with paper-based scenarios. Conclusion . Importantly, the themes of guidance and opportunity for peer discussion underlie the best forms of feedback for students. The provision of feedback following simulation should be carefully considered and delivered, with all three simulation modalities producing both positive and negative experiences in regard to their feedback format.

Electrotechnical prospects for superconducting applications

NASA Astrophysics Data System (ADS)

Brunet, Y.; Renard, M.

After a review of the classical limitations, due to iron and copper losses, we give the necessary superconducting properties, needed to achieve significant progresses, either in the size, or in the efficiency of electrotechnical plants. The successive achievement in SC will be explained, in relation with the physics of usual SC, and the needed properties for technology. The problems encountered in electrotechnics by decreasing interest are : networks losses and stability, storage of energy production, transformation and protection. In each case, SC solutions may be found or at least imagined. We shall review the limitations estimated in each case, generally by extrapolation of small scale experiments, with 4 K SC, and try to see what are the modifications which may be obtained by the use of high Tc SC. Special attention will be paid to energy storage and electrical machinery and the interest of completely superconducting plants will be shown. Une fois précisées les limitations actuelles des matériels électriques imposées essentiellement par l'utilisation de matériaux comme le fer ou le cuivre, nous détaillons les caractéristiques des supraconducteurs susceptibles d'améliorer les performances des installations électrotechniques. Les progrès successifs des conducteurs supraconducteurs sont expliqués en tenant compte de leur impact technologique. Les problèmes rencontrés en électrotechnique sont : les pertes et la stabilité des réseaux, le stockage et la production de l'énergie. Dans chaque cas des solutions supraconductrices existent ou peuvent être imaginées. Nous examinons notamment pour les machines électriques et le stockage de l'énergie, les solutions qui existent ou sont en cours de développement avec des supraconducteurs à basse température (˜ 4 K) et quelles sont les modifications apportées par l'utilisation de supraconducteurs à haut Tc.

Le recours aux modeles dans l'enseignement de la biologie au secondaire : Conceptions d'enseignantes et d'enseignants et modes d'utilisation

NASA Astrophysics Data System (ADS)

Varlet, Madeleine

Le recours aux modeles et a la modelisation est mentionne dans la documentation scientifique comme un moyen de favoriser la mise en oeuvre de pratiques d'enseignement-apprentissage constructivistes pour pallier les difficultes d'apprentissage en sciences. L'etude prealable du rapport des enseignantes et des enseignants aux modeles et a la modelisation est alors pertinente pour comprendre leurs pratiques d'enseignement et identifier des elements dont la prise en compte dans les formations initiale et disciplinaire peut contribuer au developpement d'un enseignement constructiviste des sciences. Plusieurs recherches ont porte sur ces conceptions sans faire de distinction selon les matieres enseignees, telles la physique, la chimie ou la biologie, alors que les modeles ne sont pas forcement utilises ou compris de la meme maniere dans ces differentes disciplines. Notre recherche s'est interessee aux conceptions d'enseignantes et d'enseignants de biologie au secondaire au sujet des modeles scientifiques, de quelques formes de representations de ces modeles ainsi que de leurs modes d'utilisation en classe. Les resultats, que nous avons obtenus au moyen d'une serie d'entrevues semi-dirigees, indiquent que globalement leurs conceptions au sujet des modeles sont compatibles avec celle scientifiquement admise, mais varient quant aux formes de representations des modeles. L'examen de ces conceptions temoigne d'une connaissance limitee des modeles et variable selon la matiere enseignee. Le niveau d'etudes, la formation prealable, l'experience en enseignement et un possible cloisonnement des matieres pourraient expliquer les differentes conceptions identifiees. En outre, des difficultes temporelles, conceptuelles et techniques peuvent freiner leurs tentatives de modelisation avec les eleves. Toutefois, nos resultats accreditent l'hypothese que les conceptions des enseignantes et des enseignants eux-memes au sujet des modeles, de leurs formes de representation et de leur approche constructiviste en enseignement representent les plus grands obstacles a la construction des modeles en classe. Mots-cles : Modeles et modelisation, biologie, conceptions, modes d'utilisation, constructivisme, enseignement, secondaire.

Explorer : des clés pour mieux comprendre la matière

ScienceCinema

Ellis, Jonathan R.

2018-01-12

Will the LHC upset theories of the infinitely small? Physicists would like the accelerator to shake the standard model. This theory of elementary particles and forces leaves many gray areas. The LHC and its experiments have been designed to enlighten them. [Le LHC va-t-il bouleverser les théories de l'infiniment petit ? Les physiciens aimeraient que l'accélérateur fasse trembler le modèle standard. Cette théorie des particules élémentaires et des forces laisse de nombreuses zones d'ombre. Le LHC et ses expériences ont été conçus pour les éclairer.

Simulation of turbulent shear flows at Stanford and NASA-Ames - What can we do and what have we learned?

NASA Technical Reports Server (NTRS)

Reynolds, W. C.

1983-01-01

The capabilities and limitations of large eddy simulation (LES) and full turbulence simulation (FTS) are outlined. It is pointed out that LES, although limited at the present time by the need for periodic boundary conditions, produces large-scale flow behavior in general agreement with experiments. What is more, FTS computations produce small-scale behavior that is consistent with available experiments. The importance of the development work being done on the National Aerodynamic Simulator is emphasized. Studies at present are limited to situations in which periodic boundary conditions can be applied on boundaries of the computational domain where the flow is turbulent.

Model Validation for Propulsion - On the TFNS and LES Subgrid Models for a Bluff Body Stabilized Flame

NASA Technical Reports Server (NTRS)

Wey, Thomas

2017-01-01

This paper summarizes the reacting results of simulating a bluff body stabilized flame experiment of Volvo Validation Rig using a releasable edition of the National Combustion Code (NCC). The turbulence models selected to investigate the configuration are the sub-grid scaled kinetic energy coupled large eddy simulation (K-LES) and the time-filtered Navier-Stokes (TFNS) simulation. The turbulence chemistry interaction used is linear eddy mixing (LEM).

LES of flow in the street canyon

NASA Astrophysics Data System (ADS)

Fuka, Vladimír; Brechler, Josef

2012-04-01

Results of computer simulation of flow over a series of street canyons are presented in this paper. The setup is adapted from an experimental study by [4] with two different shapes of buildings. The problem is simulated by an LES model CLMM (Charles University Large Eddy Microscale Model) and results are analysed using proper orthogonal decomposition and spectral analysis. The results in the channel (layout from the experiment) are compared with results with a free top boundary.

A Feedback Model for Data-Rich Learning Experiences

ERIC Educational Resources Information Center

Pardo, Abelardo

2018-01-01

Feedback has been identified as one of the factors with the largest potential for a positive impact in a learning experience. There is a significant body of knowledge studying feedback and providing guidelines for its implementation in learning environments. In parallel, the areas of learning analytics or educational data mining have emerged to…

Exploring Trainer and Trainee Emotional Talk in Narratives about Workplace-Based Feedback Processes

ERIC Educational Resources Information Center

Dennis, A. A.; Foy, M. J.; Monrouxe, L. V.; Rees, C. E.

2018-01-01

Emotion characterises learners' feedback experiences. While the failure-to-fail literature suggests that emotion may be important, little is known about the role of emotion for educators. Secondary analyses were therefore conducted on data exploring 110 trainers' and trainees' feedback experiences. Group and individual narrative interviews were…

A Comparison of Written, Vocal, and Video Feedback When Training Teachers

ERIC Educational Resources Information Center

Luck, Kally M.; Lerman, Dorothea C.; Wu, Wai-Ling; Dupuis, Danielle L.; Hussein, Louisa A.

2018-01-01

We compared the effectiveness of and preference for different feedback strategies when training six special education teachers during a 5-day summer training program. In Experiment 1, teachers received written or vocal feedback while learning to implement two different types of preference assessments. In Experiment 2, we compared either written or…

A Study of Adaptive Relevance Feedback - UIUC TREC-2008 Relevance Feedback Experiments

DTIC Science & Technology

2008-11-01

terms. Journal of the American Society for Information Science, 27(3):129–146, 1976. [7] J . J . Rocchio. Relevance feedback in information retrieval. In...In The SMART Retrieval System: Experiments in Automatic Document Processing, pages 313–323. Prentice-Hall Inc., 1971. [8] Gerard Salton and Chris

The role of feedback in implicit and explicit artificial grammar learning: a comparison between dyslexic and non-dyslexic adults.

PubMed

Schiff, Rachel; Sasson, Ayelet; Star, Galit; Kahta, Shani

2017-10-01

The importance of feedback for learning has been firmly established over the past few decades. The question of whether feedback plays a significant role in the statistical learning abilities of adults with dyslexia, however, is currently unresolved. Here, we examined the role of feedback in grammaticality judgment, type of structural knowledge, and confidence rating in both typically developed and dyslexic adults. We implemented two artificial grammar learning experiments: implicit and explicit. The second experiment was directly analogous to the first experiment in all respects except training format: the standard memorization instruction was replaced with an explicit rule-search instruction. Each experiment was conducted with and without performance feedback. While both groups showed significantly improved learning in the feedback-based explicit artificial grammar learning task, only the typically developed adults demonstrated higher levels of conscious structural knowledge. The present study demonstrates that the basis for the grammaticality judgment of adults with dyslexia differs from that of typically developed adults, regardless of increase in the level of explicitness.

Domain structure in biphenyl incommensurate phase II observed by electron paramagnetic resonance

NASA Astrophysics Data System (ADS)

Véron, A.; Emery, J.; Spiesser, M.

1994-11-01

The domain structure in incommensurate phase II of single biphenyl crystal has been observed by investigations of the optically excited states of the Electronic Paramagnetic Resonance (E.P.R.) deuterated naphthalene molecular probes which substitute biphenyl molecules. Our results confirm that this phase is a 1q bi-domain one. The analysis of the spectra obtained in X band (9.5 GHz) experiments, in relation with the spin Hamiltonian parameter properties permits us to show that the E.P.R. probe rotates around a direction perpendicular to its long axis while the biphenyl molecule undergoes a twist movement around this axis. They also account for a regime which is like a “ multi-soliton " regime while the modulation is a plane wave one in the pure single crystal. The two molecules of the high temperature cell do not exactly experience the saure displacement field in the incommensurate phase and consequently the two domains can be distinguished. The spin Hamiltonian parameters which characterize the E.P.R. probes have been determined in the incommensurate phase II of biphenyl. La structure en domaines de la phase II du biphényle est mise en évidence par les investigations dans les états photo-excités des molécules de naphtalène deutéré, utilisées comme sondes de Résonance Paramagnétique Electronique, se substituant de manière diluée dans le mono-cristal de biphényle. Ceci confirme que cette phase est 1q bi-domaine. L'analyse des spectres obtenus dans des expériences en bande X (9.5 GHz) en relation avec les propriétés de l'hamiltonien de spin permet de montrer que la sonde moléculaire tourne autour d'une direction perpendiculaire à son grand axe alors que la molécule de biphényle subit un mouvement de twist autour de cet axe. Les résultats montrent que ces sondes rendent compte d'un régime qui est comme un régime “ multi-solitons " alors que la modulation est plane dans le cristal pur. Les deux molécules sondes de la cellule élémentaire haute température ne subissent pas les mêmes champs de déplacements dans la phase incommensurable et en conséquence les deux domaines peuvent être distingués. Les paramètres de l'hamiltonien de spin qui caractérisent les sondes R.P.E. ont été déterminés dans la phase II du biphényle.

A study on haptic collaborative game in shared virtual environment

NASA Astrophysics Data System (ADS)

Lu, Keke; Liu, Guanyang; Liu, Lingzhi

2013-03-01

A study on collaborative game in shared virtual environment with haptic feedback over computer networks is introduced in this paper. A collaborative task was used where the players located at remote sites and played the game together. The player can feel visual and haptic feedback in virtual environment compared to traditional networked multiplayer games. The experiment was desired in two conditions: visual feedback only and visual-haptic feedback. The goal of the experiment is to assess the impact of force feedback on collaborative task performance. Results indicate that haptic feedback is beneficial for performance enhancement for collaborative game in shared virtual environment. The outcomes of this research can have a powerful impact on the networked computer games.

Enhancing the learning of sport skills through external-focus feedback.

PubMed

Wulf, Gabriele; McConnel, Nathan; Gärtner, Matthias; Schwarz, Andreas

2002-06-01

The authors examined how the effectiveness of feedback for the learning of complex motor skills is affected by the focus of attention it induces. The feedback referred specifically either to body movements (internal focus) or to movement effects (external focus). In Experiment 1, groups of novices and advanced volleyball players (N = 48) practiced "tennis" serves under internal-focus or external-focus feedback conditions in a 2 (expertise) x 2 (feedback type) design. Type of feedback did not differentially affect movement quality, but external-focus feedback resulted in greater accuracy of the serves than internal-focus feedback during both practice and retention, independent of the level of expertise. In Experiment 2, the effects of relative feedback frequency as a function of attentional focus were examined. A 2 (feedback frequency: 100% vs. 33%) x 2 (feedback type) design was used. Experienced soccer players (N = 52) were required to shoot lofted passes at a target. External-focus feedback resulted in greater accuracy than internal-focus feedback did. In addition, reduced feedback frequency was beneficial under internal-focus feedback conditions, whereas 100% and 33% feedback were equally effective under external-focus conditions. The results demonstrate the effectiveness of effect-related, as opposed to movement-related, feedback and also suggest that there is a need to revise current views regarding the role of feedback for motor learning.

The experience of agency in sequence production with altered auditory feedback.

PubMed

Couchman, Justin J; Beasley, Robertson; Pfordresher, Peter Q

2012-03-01

When speaking or producing music, people rely in part on auditory feedback - the sounds associated with the performed action. Three experiments investigated the degree to which alterations of auditory feedback (AAF) during music performances influence the experience of agency (i.e., the sense that your actions led to auditory events) and the possible link between agency and the disruptive effect of AAF on production. Participants performed short novel melodies from memory on a keyboard. Auditory feedback during performances was manipulated with respect to its pitch contents and/or its synchrony with actions. Participants rated their experience of agency after each trial. In all experiments, AAF reduced judgments of agency across conditions. Performance was most disrupted (measured by error rates and slowing) when AAF led to an ambiguous experience of agency, suggesting that there may be some causal relationship between agency and disruption. However, analyses revealed that these two effects were probably independent. A control experiment verified that performers can make veridical judgments of agency. Published by Elsevier Inc.

Analysis of a Simulation Experiment on Optimized Crewing for Damage Control

DTIC Science & Technology

2012-06-01

base donnaient un rendement supérieur à l’automatisation moyenne pour l’intervention en cas d’inondation. À partir de ces analyses, les auteurs du...et l’analyse ultérieures de données aux fins d’expériences de simulation semblables. Enfin, les auteurs du rapport ont établi des pistes...DRDC Toronto. [6] Floyd, J., Hunt, S., Williams, F., & Tatem, P. (2004). Fire + Smoke Simulator (FSSIM), Version 1 - Theory manual (NRL/MR/6180-04

Network Enabled Operations: The Experiences of Senior Canadian Commanders

DTIC Science & Technology

2006-03-31

d’opérations par réseaux dans ce pays, qu’il n’y a pas de solution universelle car, selon les commandants interrogés, les besoins en réseaux...was provide by Lerhe who said that the commander must understand his communications systems sufficiently to appreciate the allocation of bandwidth...alter bandwidth allocation as he moves from the operational theatre (at sea) to port and vice versa. More specifically, this officer felt that a task

Catching Up or Falling Behind? Continuing Wealth Disparities for Immigrants to Canada by Region of Origin and Cohort.

PubMed

Maroto, Michelle; Aylsworth, Laura

2016-11-01

This paper investigates wealth disparities among first-generation immigrants using data from the 2012 Survey of Financial Security. We apply logistic and linear regression models to estimate disparities in homeownership and household equivalent net worth by immigrant status, region of origin, and time since arrival. By focusing on immigrant families from different regions who entered Canada at different points in time, this research applies theories related to assimilation, human capital, and structural barriers to wealth. Our findings demonstrate that even though many immigrant families transition into homeownership and grow their wealth over time, certain first-generation immigrant groups continue to experience wealth disparities many years after their arrival to Canada. In particular, immigrant families from African, Asian, and Middle Eastern countries experienced the largest wealth gaps. Cet article examine les disparités de richesse entre les immigrants de première génération en utilisant les données de l'Enquête 2012 sur la sécurité financière. Nous appliquons des modèles de régression logistique et linéaire pour estimer les disparités dans la propriété et valeur nette des ménages équivalente par le statut d'immigrant, la région d'origine, et le temps écoulé depuis leur arrivée. En se concentrant sur les familles d'immigrants de différentes régions qui sont entrés au Canada à différents points dans le temps, cette recherche applique les théories liées à l'assimilation, le capital humain, et les obstacles structurels à la richesse. Nos résultats démontrent que même si de nombreuses familles d'immigrants transition vers la propriété et de croître leur richesse au fil du temps, certains groupes d'immigrants de première génération continuent d'éprouver des disparités de richesse de nombreuses années après leur arrivée au Canada. En particulier, les familles d'immigrants d'Afrique, d'Asie, et les pays du Moyen-Orient ont connu les plus grands écarts de richesse. © 2016 Canadian Sociological Association/La Société canadienne de sociologie.

Effects of generic versus non-generic feedback on motor learning in children.

PubMed

Chiviacowsky, Suzete; Drews, Ricardo

2014-01-01

Non-generic feedback refers to a specific event and implies that performance is malleable, while generic feedback implies that task performance reflects an inherent ability. The present study examined the influences of generic versus non-generic feedback on motor performance and learning in 10-year-old children. In the first experiment, using soccer ball kicking at a target as a task, providing participants with generic feedback resulted in worse performance than providing non-generic feedback, after both groups received negative feedback. The second experiment measured more permanent effects. Results of a retention test, performed one day after practicing a throwing task, showed that participants who received non-generic feedback during practice outperformed the generic feedback group, after receiving a negative feedback statement. The findings demonstrate the importance of the wording of feedback. Even though different positive feedback statements may not have an immediate influence on performance, they can affect performance, and presumably individuals' motivation, when performance is (purportedly) poor. Feedback implying that performance is malleable, rather than due to an inherent ability, seems to have the potential to inoculate learners against setbacks--a situation frequently encountered in the context of motor performance and learning.

Effects of Generic versus Non-Generic Feedback on Motor Learning in Children

PubMed Central

Chiviacowsky, Suzete; Drews, Ricardo

2014-01-01

Non-generic feedback refers to a specific event and implies that performance is malleable, while generic feedback implies that task performance reflects an inherent ability. The present study examined the influences of generic versus non-generic feedback on motor performance and learning in 10-year-old children. In the first experiment, using soccer ball kicking at a target as a task, providing participants with generic feedback resulted in worse performance than providing non-generic feedback, after both groups received negative feedback. The second experiment measured more permanent effects. Results of a retention test, performed one day after practicing a throwing task, showed that participants who received non-generic feedback during practice outperformed the generic feedback group, after receiving a negative feedback statement. The findings demonstrate the importance of the wording of feedback. Even though different positive feedback statements may not have an immediate influence on performance, they can affect performance, and presumably individuals' motivation, when performance is (purportedly) poor. Feedback implying that performance is malleable, rather than due to an inherent ability, seems to have the potential to inoculate learners against setbacks – a situation frequently encountered in the context of motor performance and learning. PMID:24523947

Utilising feedback from patients and their families as a learning strategy in a Foundation Degree in palliative and supportive care: a qualitative study.

PubMed

Pal, Laura M; Dixon, Rachael E; Faull, Christina M

2014-03-01

In the UK, support workers provide much of the care that palliative care patients receive, and a novel Foundation Degree was developed to enhance their skills. Feedback on performance is a recognised educational tool that reinforces good practice, and gives insight into areas of weakness, but its use with this workforce has not been described. The aim of this qualitative study is to explore tutor and support workers' experiences of seeking and receiving feedback from patients and their families; focusing on its values and challenges. Support workers enrolled onto the Foundation Degree in Palliative and Supportive Care, were asked to seek feedback from patients and/or their families about the care that they provided using a 'My Experience' questionnaire. Forms were returned anonymously to the course tutor who discussed results with the student as a formative education strategy. The students' experience of this was explored in focus group interviews at three time points. Two tutors' experiences were similarly explored. Results were analysed thematically. Students enjoyed receiving feedback. Positive feedback helped to increase confidence, and negative feedback allowed students to look critically at their practice and identify areas of weakness. Some experienced challenges in approaching patients/families due to having a small number of suitable patients/families; a reluctance to burden patients; high patient turnover and brevity of care relationships. The tutors enjoyed delivering feedback, recognising its benefits as an educational strategy. Some concern was expressed about how to balance delivering negative feedback while continuing to provide tutorial support throughout the Foundation Degree. User feedback is considered a key formative educational strategy. Its use in health and social support workers is not established. The experiences of students and tutors in this Foundation Degree demonstrate some of the benefits and challenges of this as an educational strategy. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigating three types of continuous auditory feedback in visuo-manual tracking.

PubMed

Boyer, Éric O; Bevilacqua, Frédéric; Susini, Patrick; Hanneton, Sylvain

2017-03-01

The use of continuous auditory feedback for motor control and learning is still understudied and deserves more attention regarding fundamental mechanisms and applications. This paper presents the results of three experiments studying the contribution of task-, error-, and user-related sonification to visuo-manual tracking and assessing its benefits on sensorimotor learning. First results show that sonification can help decreasing the tracking error, as well as increasing the energy in participant's movement. In the second experiment, when alternating feedback presence, the user-related sonification did not show feedback dependency effects, contrary to the error and task-related feedback. In the third experiment, a reduced exposure of 50% diminished the positive effect of sonification on performance, whereas the increase of the average energy with sound was still significant. In a retention test performed on the next day without auditory feedback, movement energy was still superior for the groups previously trained with the feedback. Although performance was not affected by sound, a learning effect was measurable in both sessions and the user-related group improved its performance also in the retention test. These results confirm that a continuous auditory feedback can be beneficial for movement training and also show an interesting effect of sonification on movement energy. User-related sonification can prevent feedback dependency and increase retention. Consequently, sonification of the user's own motion appears as a promising solution to support movement learning with interactive feedback.

A further assessment of vegetation feedback on decadal Sahel rainfall variability

NASA Astrophysics Data System (ADS)

Kucharski, Fred; Zeng, Ning; Kalnay, Eugenia

2013-03-01

The effect of vegetation feedback on decadal-scale Sahel rainfall variability is analyzed using an ensemble of climate model simulations in which the atmospheric general circulation model ICTPAGCM ("SPEEDY") is coupled to the dynamic vegetation model VEGAS to represent feedbacks from surface albedo change and evapotranspiration, forced externally by observed sea surface temperature (SST) changes. In the control experiment, where the full vegetation feedback is included, the ensemble is consistent with the observed decadal rainfall variability, with a forced component 60 % of the observed variability. In a sensitivity experiment where climatological vegetation cover and albedo are prescribed from the control experiment, the ensemble of simulations is not consistent with the observations because of strongly reduced amplitude of decadal rainfall variability, and the forced component drops to 35 % of the observed variability. The decadal rainfall variability is driven by SST forcing, but significantly enhanced by land-surface feedbacks. Both, local evaporation and moisture flux convergence changes are important for the total rainfall response. Also the internal decadal variability across the ensemble members (not SST-forced) is much stronger in the control experiment compared with the one where vegetation cover and albedo are prescribed. It is further shown that this positive vegetation feedback is physically related to the albedo feedback, supporting the Charney hypothesis.

A Written, Reflective and Dialogic Strategy for Assessment Feedback That Can Enhance Student/Teacher Relationships

ERIC Educational Resources Information Center

Crimmins, Gail; Nash, Gregory; Oprescu, Florin; Liebergreen, Marama; Turley, Janet; Bond, Richard; Dayton, Jeanne

2016-01-01

In response to the shortcomings of current assessment feedback practice, this paper presents the results of a study designed to examine students' and teachers' experience of engaging in a written, reflective and dialogic feedback (WRDF) strategy. The strategy was designed to enhance the learning experience of students undertaking a large…

Examining recognition criterion rigidity during testing using a biased feedback technique: Evidence for adaptive criterion learning

PubMed Central

Han, Sanghoon; Dobbins, Ian G.

2009-01-01

Recognition models often assume that subjects use specific evidence values (decision criteria) to adaptively parse continuous memory evidence into response categories (e.g., “old” or “new”). Although explicit pre-test instructions influence criterion placement, these criteria appear extremely resistant to change once testing begins. We tested criterion sensitivity to local feedback using a novel, biased feedback technique designed to tacitly encourage certain errors by indicating they were correct choices. Experiment 1 demonstrated that fully correct feedback had little effect on criterion placement, whereas biased feedback during Experiments 2 and 3 yielded prominent, durable, and adaptive criterion shifts, with observers reporting they were unaware of the manipulation in Experiment 3. These data suggest recognition criteria can be easily modified during testing through a form of feedback learning that operates independent of stimulus characteristics and observer awareness of the nature of the manipulation. This mechanism may be fundamentally different than criterion shifts following explicit instructions and warnings, or shifts linked to manipulations of stimulus characteristics combined with feedback highlighting those manipulations. PMID:18604954

Learning from Feedback: Spacing and the Delay-Retention Effect

ERIC Educational Resources Information Center

Smith, Troy A.; Kimball, Daniel R.

2010-01-01

Most modern research on the effects of feedback during learning has assumed that feedback is an error correction mechanism. Recent studies of feedback-timing effects have suggested that feedback might also strengthen initially correct responses. In an experiment involving cued recall of trivia facts, we directly tested several theories of…

Feedback in Action--The Mechanism of the Iris.

ERIC Educational Resources Information Center

Pingnet, B.; And Others

1988-01-01

Describes two demonstration experiments. Outlines a demonstration of the general principle of positive and negative feedback and the influence of time delays in feedback circuits. Elucidates the principle of negative feedback with a model of the iris of the eye. Emphasizes the importance of feedback in biological systems. (CW)

Exploring Occupational Therapy Students' Meaning of Feedback during Fieldwork Experiences

ERIC Educational Resources Information Center

Rathgeber, Karen Lynne

2014-01-01

Researchers have revealed that students' confidence and performance improve after they receive feedback from clinical supervisors regarding the delivery of quality patient care. Multiple studies of feedback have focused on the provision and acceptance of feedback; however, it was not known if or how students internalized feedback to promote…

Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment.

PubMed

Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

2016-01-01

Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies.

Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment

PubMed Central

Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

2016-01-01

Background Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. Aims and Methods In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. Key Results In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. Conclusions All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies. PMID:27336400

Interactions électron-électron dans les fils mésoscopiques

NASA Astrophysics Data System (ADS)

Pierre, F.

Electron-electron interactions in mesoscopic wires In metallic thin films, the screening of Coulomb interactions is less efficient than in bulk metals because of electron elastic scattering from film boundaries, lattice defects, and impurities. As a consequence, at sub-kelvin temperatures, electron-electron interactions are expected to be the dominant inelastic process undergone by electrons, which determines energy exchange and limits the electronic phase coherence. We present in this book three experiments that probe inelastic collisions experienced by electrons at low temperature, in order to find out their mechanism. In the first part, we present a series of measurements of the energy distribution function of electrons in copper, gold and silver wires driven in a steady-state, out of equilibrium situation. These experiments reveal the rate at which electrons exchange energy. These results are compared in the second part with the temperature dependence of the phase coherence time of electrons tau_{φ}, which is deduced from the magnetoresistance of long wires. The phase coherence of electrons is limited by all inelastic collisions, independently of the energy exchanged. Different mechanisms to account for the energy exchange rate and dephasing times are proposed and compared with experiments. In the third part, we present measurements of the conductance of a long tunnel junction between an aluminum wire and a ground plane. The dip in the conductance at zero voltage is expected from the theory of electron-electron interactions. To compare measurements and theoretical predictions, we rephrase the microscopic theory of electron-electron interactions in terms of an electromagnetic impedance, as is done for the phenomenological theory of Coulomb blockade. Dans les couches minces métalliques, l'écrantage des interactions coulombiennes entre électrons est moins efficace que dans les métaux massifs en raison des chocs élastiques que subissent les électrons sur les parois, les défauts du réseau cristallin et les impuretés. Aux températures inférieures au kelvin, il est prédit que ces interactions électron-électron sont à l'origine de la plupart des collisions inélastiques subies par les électrons, et déterminent donc les échanges d'énergie et l'extension de la cohérence de phase. Nous présentons dans cet ouvrage trois expériences qui sondent les interactions inélastiques subies par les électrons dans les métaux diffusifs à basse température, afin d'en élucider le mécanisme. Dans la première partie, nous présentons une série de mesures de la fonction de distribution en énergie des électrons dans des fils mésoscopiques d'argent, de cuivre et d'or placés dans un régime stationnaire hors-équilibre. Ces expériences permettent d'accéder au taux d'échange d'énergie entre électrons. Ces résultats sont comparés dans la deuxième partie avec la dépendance en température du temps de cohérence de phase des électrons tau_{φ}, que l'on déduit de la mesure de la magnétorésistance de longs fils. La cohérence de phase des électrons dépend du taux total de collisions inélastiques, indépendamment de l'énergie échangée. Nous discutons divers mécanismes d'interaction pour rendre compte à la fois des mesures des taux d'échange d'énergie et du temps de cohérence de phase, et les comparons quantitativement aux résultats expérimentaux. La troisième partie est consacrée à la mesure de la conductance d'une longue jonction tunnel entre un fil d'aluminium et un plan de masse. La diminution de cette conductance à tension nulle est un effet attendu des interactions électron-électron. Pour comparer mesures et prédictions théoriques, nous avons reformulé les prédictions du calcul microscopique des interactions entre électrons en terme d'impédance électromagnétique, dans un langage similaire à celui utilisé pour la théorie phénoménologique du blocage de Coulomb.

Numerical simulation of air distribution in a room with a sidewall jet under benchmark test conditions

NASA Astrophysics Data System (ADS)

Zasimova, Marina; Ivanov, Nikolay

2018-05-01

The goal of the study is to validate Large Eddy Simulation (LES) data on mixing ventilation in an isothermal room at conditions of benchmark experiments by Hurnik et al. (2015). The focus is on the accuracy of the mean and rms velocity fields prediction in the quasi-free jet zone of the room with 3D jet supplied from a sidewall rectangular diffuser. Calculations were carried out using the ANSYS Fluent 16.2 software with an algebraic wall-modeled LES subgrid-scale model. CFD results on the mean velocity vector are compared with the Laser Doppler Anemometry data. The difference between the mean velocity vector and the mean air speed in the jet zone, both LES-computed, is presented and discussed.

Developing leaders via experience: the role of developmental challenge, learning orientation, and feedback availability.

PubMed

Derue, D Scott; Wellman, Ned

2009-07-01

Prior research offers limited insight into the types of work experiences that promote leadership skill development and the ways that the person and context shape the developmental value of these experiences. In this article, the authors develop a series of hypotheses linking leadership skill development to features of the experience (developmental challenge), person (learning orientation), and context (feedback availability). Based on 225 on-the-job experiences across 60 managers, their results demonstrate that the relationship between developmental challenge and leadership skill development exhibits a pattern of diminishing returns. However, access to feedback can offset the diminishing returns associated with high levels of developmental challenge.

Feedback in clinical practice: Enhancing the students' experience through action research.

PubMed

Adamson, Elizabeth; King, Linda; Foy, Lynn; McLeod, Margo; Traynor, Jennifer; Watson, Wendy; Gray, Morag

2018-05-01

Feedback within clinical practice is known to be central to the learning and development of student nurses and midwives. A study that focused on student experience of assessment identified that a high proportion of students reported that they had received insufficient feedback whilst on clinical placement. In response to this academics and members of the clinical education team set out to explore this with a view to improving the student experience using action research. Key findings indicated that responsibility for feedback on clinical placement lies with both students and mentors, distinct factors can enable effective feedback and that positive outcomes for mentors and students resulted through engaging with the project. The process, outcomes and actions taken to improve practice are the focus of this paper. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigating Qualities of Teachers' Feedback Conversations for Fostering Reasoning and Feeling of Self-Worth in Learners: A Tool Called Feedback Mapping

ERIC Educational Resources Information Center

Quynn, Jennifer Ann

2013-01-01

Teacher feedback has been identified throughout the educational literature as a powerful classroom intervention. However few tools exist that allow teachers to understand their own feedback practice. This study details a method for evaluating the feedback experiences of students. The feedback conversations of middle school science teachers were…

Capturing patient experience: a qualitative study of implementing real-time feedback in primary care

PubMed Central

Carter, Mary; Davey, Antoinette; Wright, Christine; Elmore, Natasha; Newbould, Jenny; Roland, Martin; Campbell, John; Burt, Jenni

2016-01-01

Background In recent years, hospitals have made use of new technologies, such as real-time feedback, to collect patient experience information. This approach is currently rarely used in primary care settings, but may provide practices with a useful tool that enables them to take prompt, focused action to improve their services. Aim To identify the factors inhibiting and enabling the implementation of real-time feedback in general practices. Design and setting Qualitative study embedded within an exploratory trial (July 2014 to February 2015) of a real-time feedback intervention targeting patient experience in general practices in south-west England and Cambridgeshire. Method Semi-structured interviews (n = 22) and focus groups (n = 4, total of 28 attendees) with practice staff were audiorecorded, transcribed, and analysed thematically, using a framework based on constructs from normalisation process theory. Results Staff engagement with real-time feedback varied considerably, and staff made sense of real-time feedback by comparing it with more familiar feedback modalities. Effective within-team communication was associated with positive attitudes towards real-time feedback. Timing of requests for feedback was important in relation to patient engagement. Real-time feedback may offer potential as a means of informing practice development, perhaps as a component of a wider programme of capturing and responding to patients’ comments. Conclusion Successful implementation of real-time feedback requires effective communication across the practice team to engender thorough engagement. Feedback processes should be carefully introduced to fit with existing patient and practice routines. Future studies should consider making real-time feedback content relevant to specific practice needs, and support participation by all patient groups. PMID:27621292

Vagal Afferent Innervation of the Lower Esophageal Sphincter

PubMed Central

Powley, Terry L.; Baronowsky, Elizabeth A.; Gilbert, Jared M.; Hudson, Cherie N.; Martin, Felecia N.; Mason, Jacqueline K.; McAdams, Jennifer L.; Phillips, Robert J.

2013-01-01

To supply a fuller morphological characterization of the vagal afferents innervating the lower esophageal sphincter (LES), specifically to label vagal terminals in the tissues forming the LES in the gastroesophageal junction, the present experiment employed injections of dextran biotin into the nodose ganglia of rats. Four types of vagal afferents innervated the LES. Clasp and sling muscle fibers were directly and prominently innervated by intramuscular arrays (IMAs). Individual IMA terminals subtended about 16° of arc of the esophageal circumference, and, collectively, the terminal fields were distributed within the muscle ring to establish a 360° annulus of mechanoreceptors in the sphincter wall. 3D morphometry of the terminals established that, compared to sling muscle IMAs, clasp muscle IMAs had more extensive arbors and larger receptive fields. In addition, at the cardia, local myenteric ganglia between smooth muscle sheets and striated muscle bundles were innervated by intraganglionic laminar endings (IGLEs), in a pattern similar to the innervation of the myenteric plexus throughout the stomach and esophagus. Finally, as previously described, the principle bundle of sling muscle fibers that links LES sphincter tissue to the antropyloric region of the lesser curvature was innervated by exceptionally long IMAs as well as by unique web ending specializations at the distal attachment of the bundle. Overall, the specialized varieties of densely distributed vagal afferents innervating the LES underscore the conclusion that these sensory projections are critically involved in generating LES reflexes and may be promising targets for managing esophageal dysfunctions. PMID:23583280

Micro Blowing Simulations Using a Coupled Finite-Volume Lattice-Boltzman n L ES Approach

NASA Technical Reports Server (NTRS)

Menon, S.; Feiz, H.

1990-01-01

Three dimensional large-eddy simulations (LES) of single and multiple jet-in-cross-flow (JICF) are conducted using the 19-bit Lattice Boltzmann Equation (LBE) method coupled with a conventional finite-volume (FV) scheme. In this coupled LBE-FV approach, the LBE-LES is employed to simulate the flow inside the jet nozzles while the FV-LES is used to simulate the crossflow. The key application area is the use of this technique is to study the micro blowing technique (MBT) for drag control similar to the recent experiments at NASA/GRC. It is necessary to resolve the flow inside the micro-blowing and suction holes with high resolution without being restricted by the FV time-step restriction. The coupled LBE-FV-LES approach achieves this objectives in a computationally efficient manner. A single jet in crossflow case is used for validation purpose and the results are compared with experimental data and full LBE-LES simulation. Good agreement with data is obtained. Subsequently, MBT over a flat plate with porosity of 25% is simulated using 9 jets in a compressible cross flow at a Mach number of 0.4. It is shown that MBT suppresses the near-wall vortices and reduces the skin friction by up to 50 percent. This is in good agreement with experimental data.

Bayesian source term estimation of atmospheric releases in urban areas using LES approach.

PubMed

Xue, Fei; Kikumoto, Hideki; Li, Xiaofeng; Ooka, Ryozo

2018-05-05

The estimation of source information from limited measurements of a sensor network is a challenging inverse problem, which can be viewed as an assimilation process of the observed concentration data and the predicted concentration data. When dealing with releases in built-up areas, the predicted data are generally obtained by the Reynolds-averaged Navier-Stokes (RANS) equations, which yields building-resolving results; however, RANS-based models are outperformed by large-eddy simulation (LES) in the predictions of both airflow and dispersion. Therefore, it is important to explore the possibility of improving the estimation of the source parameters by using the LES approach. In this paper, a novel source term estimation method is proposed based on LES approach using Bayesian inference. The source-receptor relationship is obtained by solving the adjoint equations constructed using the time-averaged flow field simulated by the LES approach based on the gradient diffusion hypothesis. A wind tunnel experiment with a constant point source downwind of a single building model is used to evaluate the performance of the proposed method, which is compared with that of the existing method using a RANS model. The results show that the proposed method reduces the errors of source location and releasing strength by 77% and 28%, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

DOE PAGES

Moon, Jae; Manuel, Lance; Churchfield, Matthew; ...

2017-12-28

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

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

Moon, Jae; Manuel, Lance; Churchfield, Matthew

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

Fluid flow analysis behind heliostat using LES and RANS: A step towards optimized field design in desert regions

NASA Astrophysics Data System (ADS)

Boddupalli, Nibodh; Goenka, Vikash; Chandra, Laltu

2017-06-01

Heliostats are used for concentrating beam radiation onto a receiver. The flow induced dust deposition on these reflectors will lead to failure of the receiver. For this purpose, the wake behind a heliostat is analyzed at 25° of inclination and at a Reynolds number of 60000. In this paper the Reynolds Averaged Navier-Stokes (RANS) and the Large Eddy Simulation (LES) approaches are used for analyzing the air-flow behind a heliostat. LES and RANS are performed with a wall-resolved grid. For the purpose of validation, the horizontal velocity is measured in a wind-tunnel with a model heliostat using laser Doppler velocimetry technique. RANS and LES approaches are found to qualitatively predict the statistical quantities, like the mean horizontal-velocity in comparison to experiment. RANS under-predicts root-mean-square of the horizontal-velocity and even failed to capture the flow features behind heliostat. Thus, it is concluded that RANS will suffice with well-resolved grid for analyzing mean flow features. For analyzing wake and to understand the induced dust deposition LES is required. Further, the analysis reveals that the wake-affected region is up to three times the length of the heliostat's mirror. This can be recommended as the minimum distance between any two aligned heliostats in Jodhpur.

What Type of Feedback Do Student Teachers Expect from Their School Mentors during Practicum Experience? The Case of Spanish EFL Student Teachers

ERIC Educational Resources Information Center

Martínez Agudo, Juan de Dios

2016-01-01

Mentorship represents a vital component in all teacher education programmes since mentors' feedback plays an essential role in shaping candidate teachers' professional identity. The quality of feedback provided by school mentors during the practicum experience constitutes the main focus of this study. This research paper aimed at investigating…

Investigating the Effects of Multimodal Feedback through Tracking State in Pen-Based Interfaces

ERIC Educational Resources Information Center

Sun, Minghui; Ren, Xiangshi

2011-01-01

A tracking state increases the bandwidth of pen-based interfaces. However, this state is difficult to detect with default visual feedback. This paper reports on two experiments that are designed to evaluate multimodal feedback for pointing tasks (both 1D and 2D) in tracking state. In 1D pointing experiments, results show that there is a…

Social closeness and feedback modulate susceptibility to the framing effect.

PubMed

Sip, Kamila E; Smith, David V; Porcelli, Anthony J; Kar, Kohitij; Delgado, Mauricio R

2015-01-01

Although we often seek social feedback (SFB) from others to help us make decisions, little is known about how SFB affects decisions under risk, particularly from a close peer. We conducted two experiments using an established framing task to probe how decision-making is modulated by SFB valence (positive, negative) and the level of closeness with feedback provider (friend, confederate). Participants faced mathematically equivalent decisions framed as either an opportunity to keep (gain frame) or lose (loss frame) part of an initial endowment. Periodically, participants were provided with positive (e.g., "Nice!") or negative (e.g., "Lame!") feedback about their choices. Such feedback was provided by either a confederate (Experiment 1) or a gender-matched close friend (Experiment 2). As expected, the framing effect was observed in both experiments. Critically, an individual's susceptibility to the framing effect was modulated by the valence of the SFB, but only when the feedback provider was a close friend. This effect was reflected in the activation patterns of ventromedial prefrontal cortex and posterior cingulate cortex, regions involved in complex decision-making. Taken together, these results highlight social closeness as an important factor in understanding the impact of SFB on neural mechanisms of decision-making.

A Longitudinal, Quantitative Study of Student Attitudes towards Audio Feedback for Assessment

ERIC Educational Resources Information Center

Parkes, Mitchell; Fletcher, Peter

2017-01-01

This paper reports on the findings of a three-year longitudinal study investigating the experiences of postgraduate level students who were provided with audio feedback for their assessment. Results indicated that students positively received audio feedback. Overall, students indicated a preference for audio feedback over written feedback. No…

Biostereometrics In Art

NASA Astrophysics Data System (ADS)

Ferenc, Kovats

1986-07-01

Desuis mon enfance je suis un type soidisant visuel. Cette deviation etait toujours profitable pour moi, pour le clinicien , ainsi que pour le rechercheur scientifique.I1 y a trente ans, que dans l'Atlas Radioanatomique du Thorax nous avons deja utilis6 la conception de trois dimensions. Dans les derni6res edition de cet ouvrage nous avons travaille mke avec la guatrieme, le temps facteur. DePuis cette 6poque-la je me suis ori-en-be vers les quatre dimensions, vers les mouvements dans l'espace et le temps. -:tudiant les mouvements,les mouvements ventilatoires mesure par photogrammetrie le tronc humain.En projetant sur la surface du tronc un reseau quadratique, on pent compter de 3oo-400 points d'information, si un carre est 2 This 2 cm. Simultanement on pent ainsi contraler les deplacement relatifs des differents points. Travaillant avec seriophotographie et ces dernieres annees avec Video, nous avons des documents cDntinuellement en trois dimensions sun la position actuelle en espace de notre modele.On pent mesurer, reproduire la position momentan6e du sujet d'une frequence et dans la quantite desiree. Par exemple on peut les reproduire, une a une, comme une sculpture, en domontrant les changements d'un tronc humain pendant les mouvements respiratoires, comme nous avions fait en 1969 avec le sculpteur Istvan Bencsik en realisant nos differents modeles en inspiration et expiration.flais thooriquement on pent construire tant de sculptures qu'on vent entre les deux positions extremes.La methode est tres utilisable pour l'observation des mouvements sportifs on artistiques, comme le ballet par exemple. / Figure 1./ En etudiant en plusieures series la morphometrie des mouvements respiratoires on pent acquerir une certain experience, qui concerne la phase de respiration, on se trouve un corps humain sculpte, dessine on peint. Come le mimique d'un visage explkue toujours l'6tat affectif d'un individu, le corps humain peut expliquer tart des chases entre les mains d'un artiste doue. Liais nous retournerons encore a cet argument. Avec un objet d'art l'artiste registe un seul moment dune serie de mouvements de son sujet, spit en deux dimensions, s'il est peintre on graveur , dessinateur etc., spit en trois dimensions s'il est sculpteur.i:algre cela , il y a beaucoup d'oeuvresd'art dyna-miques, qui donnent l'impression de mouvement.On pent produire cet effetavec la ROMDOSi-tion des mouvements non simultanees , comme par exemple sur les tableaux de XIX 'si8cle representant des concours hyppiques, on les extremit-ees des chevaux sort distandue an maximum en avant et en arriere; c'est un mode de galop inexistant, mais malgr6, qu'il est faux, it suggere la vitesse.

Interface Prostheses With Classifier-Feedback-Based User Training.

PubMed

Fang, Yinfeng; Zhou, Dalin; Li, Kairu; Liu, Honghai

2017-11-01

It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.

FTAP: a Linux-based program for tapping and music experiments.

PubMed

Finney, S A

2001-02-01

This paper describes FTAP, a flexible data collection system for tapping and music experiments. FTAP runs on standard PC hardware with the Linux operating system and can process input keystrokes and auditory output with reliable millisecond resolution. It uses standard MIDI devices for input and output and is particularly flexible in the area of auditory feedback manipulation. FTAP can run a wide variety of experiments, including synchronization/continuation tasks (Wing & Kristofferson, 1973), synchronization tasks combined with delayed auditory feedback (Aschersleben & Prinz, 1997), continuation tasks with isolated feedback perturbations (Wing, 1977), and complex alterations of feedback in music performance (Finney, 1997). Such experiments have often been implemented with custom hardware and software systems, but with FTAP they can be specified by a simple ASCII text parameter file. FTAP is available at no cost in source-code form.

Do Those Who Benefit the Most Need it the Least? A Four-Year Experiment in Enquiry-Based Feedback

ERIC Educational Resources Information Center

Adcroft, Andy; Willis, Robert

2013-01-01

The aim of this paper is to report on an ongoing experiment in an enquiry-based approach to feedback. Over the course of four years, almost 1800 students have studied a final-year undergraduate module involving a mid-term assignment and end of module examination. Feedback on the assignment is delivered through a process which involves the…

Reality Monitoring and Feedback Control of Speech Production Are Related Through Self-Agency.

PubMed

Subramaniam, Karuna; Kothare, Hardik; Mizuiri, Danielle; Nagarajan, Srikantan S; Houde, John F

2018-01-01

Self-agency is the experience of being the agent of one's own thoughts and motor actions. The intact experience of self-agency is necessary for successful interactions with the outside world (i.e., reality monitoring) and for responding to sensory feedback of our motor actions (e.g., speech feedback control). Reality monitoring is the ability to distinguish internally self-generated information from outside reality (externally-derived information). In the present study, we examined the relationship of self-agency between lower-level speech feedback monitoring (i.e., monitoring what we hear ourselves say) and a higher-level cognitive reality monitoring task. In particular, we examined whether speech feedback monitoring and reality monitoring were driven by the capacity to experience self-agency-the ability to make reliable predictions about the outcomes of self-generated actions. During the reality monitoring task, subjects made judgments as to whether information was previously self-generated (self-agency judgments) or externally derived (external-agency judgments). During speech feedback monitoring, we assessed self-agency by altering environmental auditory feedback so that subjects listened to a perturbed version of their own speech. When subjects heard minimal perturbations in their auditory feedback while speaking, they made corrective responses, indicating that they judged the perturbations as errors in their speech output. We found that self-agency judgments in the reality-monitoring task were higher in people who had smaller corrective responses ( p = 0.05) and smaller inter-trial variability ( p = 0.03) during minimal pitch perturbations of their auditory feedback. These results provide support for a unitary process for the experience of self-agency governing low-level speech control and higher level reality monitoring.

Understanding Arts and Humanities Students' Experiences of Assessment and Feedback

ERIC Educational Resources Information Center

Adams, Joelle; McNab, Nicole

2013-01-01

This article examines how undergraduate students on arts and humanities courses experience assessment and feedback. The research uses a detailed audit, a specially devised questionnaire (the Assessment Experience Questionnaire), and student focus group data, and the article examines results from 19 programmes, comparing those from "arts and…

Can false memories be corrected by feedback in the DRM paradigm?

PubMed

McConnell, Melissa D; Hunt, R Reed

2007-07-01

Normal processes of comprehension frequently yield false memories as an unwanted by-product. The simple paradigm now known as the Deese/Roediger-McDermott (DRM) paradigm takes advantage of this fact and has been used to reliably produce false memory for laboratory study. Among the findings from past research is the difficulty of preventing false memories in this paradigm. The purpose of the present experiments was to examine the effectiveness of feedback in correcting false memories. Two experiments were conducted, in which participants recalled DRM lists and either received feedback on their performance or did not. A subsequent recall test was administered to assess the effect of feedback. The results showed promising effects of feedback: Feedback enhanced both error correction and the propagation of correct recall. The data replicated other data of studies that have shown substantial error perseveration following feedback. These data also provide new information on the occurrence of errors following feedback. The results are discussed in terms of the activation-monitoring theory of false memory.

Barriers and Facilitators to Effective Feedback: A Qualitative Analysis of Data From Multispecialty Resident Focus Groups.

PubMed

Reddy, Shalini T; Zegarek, Matthew H; Fromme, H Barrett; Ryan, Michael S; Schumann, Sarah-Anne; Harris, Ilene B

2015-06-01

Despite the importance of feedback, the literature suggests that there is inadequate feedback in graduate medical education. We explored barriers and facilitators that residents in anesthesiology, emergency medicine, obstetrics and gynecology, and surgery experience with giving and receiving feedback during their clinical training. Residents from 3 geographically diverse teaching institutions were recruited to participate in focus groups in 2012. Open-ended questions prompted residents to describe their experiences with giving and receiving feedback, and discuss facilitators and barriers. Data were transcribed and analyzed using the constant comparative method associated with a grounded theory approach. A total of 19 residents participated in 1 of 3 focus groups. Five major themes related to feedback were identified: teacher factors, learner factors, feedback process, feedback content, and educational context. Unapproachable attendings, time pressures due to clinical work, and discomfort with giving negative feedback were cited as major barriers in the feedback process. Learner engagement in the process was a major facilitator in the feedback process. Residents provided insights for improving the feedback process based on their dual roles as teachers and learners. Time pressures in the learning environment may be mitigated by efforts to improve the quality of teacher-learner relationships. Forms for collecting written feedback should be augmented by faculty development to ensure meaningful use. Efforts to improve residents' comfort with giving feedback and encouraging learners to engage in the feedback process may foster an environment conducive to increasing feedback.

Regulating recognition decisions through incremental reinforcement learning.

PubMed

Han, Sanghoon; Dobbins, Ian G

2009-06-01

Does incremental reinforcement learning influence recognition memory judgments? We examined this question by subtly altering the relative validity or availability of feedback in order to differentially reinforce old or new recognition judgments. Experiment 1 probabilistically and incorrectly indicated that either misses or false alarms were correct in the context of feedback that was otherwise accurate. Experiment 2 selectively withheld feedback for either misses or false alarms in the context of feedback that was otherwise present. Both manipulations caused prominent shifts of recognition memory decision criteria that remained for considerable periods even after feedback had been altogether removed. Overall, these data demonstrate that incremental reinforcement-learning mechanisms influence the degree of caution subjects exercise when evaluating explicit memories.

Blocked versus randomized presentation modes differentially modulate feedback-related negativity and P3b amplitudes

PubMed Central

Pfabigan, Daniela M.; Zeiler, Michael; Lamm, Claus; Sailer, Uta

2014-01-01

Objective Electrophysiological studies on feedback processing typically use a wide range of feedback stimuli which might not always be comparable. The current study investigated whether two indicators of feedback processing – feedback-related negativity (FRN) and P3b – differ for feedback stimuli with explicit (facial expressions) or assigned valence information (symbols). In addition, we assessed whether presenting feedback in either a trial-by-trial or a block-wise fashion affected these ERPs. Methods EEG was recorded in three experiments while participants performed a time estimation task and received two different types of performance feedback. Results Only P3b amplitudes varied consistently in response to feedback type for both presentation types. Moreover, the blocked feedback type presentation yielded more distinct FRN peaks, higher effect sizes, and a significant relation between FRN amplitudes and behavioral task performance measures. Conclusion Both stimulus type and presentation mode may provoke systematic changes in feedback-related ERPs. The current findings point at important potential confounds that need to be controlled for when designing FRN or P3b studies. Significance Studies investigating P3b amplitudes using mixed types of stimuli have to be interpreted with caution. Furthermore, we suggest implementing a blocked presentation format when presenting different feedback types within the same experiment. PMID:24144779

Effets des electrons secondaires sur l'ADN

NASA Astrophysics Data System (ADS)

Boudaiffa, Badia

Les interactions des electrons de basse energie (EBE) representent un element important en sciences des radiations, particulierement, les sequences se produisant immediatement apres l'interaction de la radiation ionisante avec le milieu biologique. Il est bien connu que lorsque ces radiations deposent leur energie dans la cellule, elles produisent un grand nombre d'electrons secondaires (4 x 104/MeV), qui sont crees le long de la trace avec des energies cinetiques initiales bien inferieures a 20 eV. Cependant, il n'y a jamais eu de mesures directes demontrant l'interaction de ces electrons de tres basse energie avec l'ADN, du principalement aux difficultes experimentales imposees par la complexite du milieu biologique. Dans notre laboratoire, les dernieres annees ont ete consacrees a l'etude des phenomenes fondamentaux induits par impact des EBE sur differentes molecules simples (e.g., N2, CO, O2, H2O, NO, C2H 4, C6H6, C2H12) et quelques molecules complexes dans leur phase solide. D'autres travaux effectues recemment sur des bases de l'ADN et des oligonucleotides ont montre que les EBE produisent des bris moleculaires sur les biomolecules. Ces travaux nous ont permis d'elaborer des techniques pour mettre en evidence et comprendre les interactions fondamentales des EBE avec des molecules d'interet biologique, afin d'atteindre notre objectif majeur d'etudier l'effet direct de ces particules sur la molecule d'ADN. Les techniques de sciences des surfaces developpees et utilisees dans les etudes precitees peuvent etre etendues et combinees avec des methodes classiques de biologie pour etudier les dommages de l'ADN induits par l'impact des EBE. Nos experiences ont montre l'efficacite des electrons de 3--20 eV a induire des coupures simple et double brins dans l'ADN. Pour des energies inferieures a 15 eV, ces coupures sont induites par la localisation temporaire d'un electron sur une unite moleculaire de l'ADN, ce qui engendre la formation d'un ion negatif transitoire dans un etat electronique dissociatif, cette localisation est suivie d'une fragmentation. A plus haute energie, la dissociation dipolaire (i.e., la formation simultanee d'un ion positif et negatif) et l'ionisation jouent un role important dans le dommage de l'ADN. L'ensemble de nos resultats permet d'expliquer les mecanismes de degradation de l'ADN par les EBE et d'obtenir des sections efficaces effectives des differents types de dommages.

Improving Hospital Services Based on Patient Experience Data: Current Feedback Practices and Future Opportunities.

PubMed

Kaipio, Johanna; Stenhammar, Hanna; Immonen, Susanna; Litovuo, Lauri; Axelsson, Minja; Lantto, Minna; Lahdenne, Pekka

2018-01-01

Patient feedback is considered important for healthcare organizations. However, measurement and analysis of patient reported data is useful only if gathered insights are transformed into actions. This article focuses on gathering and utilization of patient experience data at hospitals with the aim of supporting the development of patient-centered services. The study was designed to explore both current practices of collecting and utilizing patient feedback at hospitals as well as future feedback-related opportunities. Nine people working at different hierarchical levels of three university hospitals in Finland participated in in-depth interviews. Findings indicate that current feedback processes are poorly planned and inflexible. Some feedback data are gathered, but not systematically utilized. Currently, it is difficult to obtain a comprehensive picture of the situation. One future hope was to increase the amount of patient feedback to be able to better generalize and utilize the data. Based on the findings the following recommendations are given: attention to both patients' and healthcare staff's perspectives when collecting feedback, employing a coordinated approach for collecting and utilizing patient feedback, and organizational transformation towards a patient-centric culture.

Force feedback effects on single molecule hopping and pulling experiments

NASA Astrophysics Data System (ADS)

Rico-Pasto, M.; Pastor, I.; Ritort, F.

2018-03-01

Single-molecule experiments with optical tweezers have become an important tool to study the properties and mechanisms of biological systems, such as cells and nucleic acids. In particular, force unzipping experiments have been used to extract the thermodynamics and kinetics of folding and unfolding reactions. In hopping experiments, a molecule executes transitions between the unfolded and folded states at a preset value of the force [constant force mode (CFM) under force feedback] or trap position [passive mode (PM) without feedback] and the force-dependent kinetic rates extracted from the lifetime of each state (CFM) and the rupture force distributions (PM) using the Bell-Evans model. However, hopping experiments in the CFM are known to overestimate molecular distances and folding free energies for fast transitions compared to the response time of the feedback. In contrast, kinetic rate measurements from pulling experiments have been mostly done in the PM while the CFM is seldom implemented in pulling protocols. Here, we carry out hopping and pulling experiments in a short DNA hairpin in the PM and CFM at three different temperatures (6 °C, 25 °C, and 45 °C) exhibiting largely varying kinetic rates. As expected, we find that equilibrium hopping experiments in the CFM and PM perform well at 6 °C (where kinetics are slow), whereas the CFM overestimates molecular parameters at 45 °C (where kinetics are fast). In contrast, nonequilibrium pulling experiments perform well in both modes at all temperatures. This demonstrates that the same kind of feedback algorithm in the CFM leads to more reliable determination of the folding reaction parameters in irreversible pulling experiments.

Force feedback effects on single molecule hopping and pulling experiments.

PubMed

Rico-Pasto, M; Pastor, I; Ritort, F

2018-03-28

Single-molecule experiments with optical tweezers have become an important tool to study the properties and mechanisms of biological systems, such as cells and nucleic acids. In particular, force unzipping experiments have been used to extract the thermodynamics and kinetics of folding and unfolding reactions. In hopping experiments, a molecule executes transitions between the unfolded and folded states at a preset value of the force [constant force mode (CFM) under force feedback] or trap position [passive mode (PM) without feedback] and the force-dependent kinetic rates extracted from the lifetime of each state (CFM) and the rupture force distributions (PM) using the Bell-Evans model. However, hopping experiments in the CFM are known to overestimate molecular distances and folding free energies for fast transitions compared to the response time of the feedback. In contrast, kinetic rate measurements from pulling experiments have been mostly done in the PM while the CFM is seldom implemented in pulling protocols. Here, we carry out hopping and pulling experiments in a short DNA hairpin in the PM and CFM at three different temperatures (6 °C, 25 °C, and 45 °C) exhibiting largely varying kinetic rates. As expected, we find that equilibrium hopping experiments in the CFM and PM perform well at 6 °C (where kinetics are slow), whereas the CFM overestimates molecular parameters at 45 °C (where kinetics are fast). In contrast, nonequilibrium pulling experiments perform well in both modes at all temperatures. This demonstrates that the same kind of feedback algorithm in the CFM leads to more reliable determination of the folding reaction parameters in irreversible pulling experiments.

The Art of Giving Online Feedback

ERIC Educational Resources Information Center

Leibold, Nancyruth; Schwarz, Laura Marie

2015-01-01

The cultivation of providing online feedback that is positive, effective, and enhances the learning experience is a valuable educator skill. Acquisition of the art of providing feedback is through education, practice, and faculty development. This article provides information about the best practices for delivering online feedback to learners. An…

\\mathscr{H}_2 optimal control techniques for resistive wall mode feedback in tokamaks

NASA Astrophysics Data System (ADS)

Clement, Mitchell; Hanson, Jeremy; Bialek, Jim; Navratil, Gerald

2018-04-01

DIII-D experiments show that a new, advanced algorithm enables resistive wall mode (RWM) stability control in high performance discharges using external coils. DIII-D can excite strong, locked or nearly locked external kink modes whose rotation frequencies and growth rates are on the order of the magnetic flux diffusion time of the vacuum vessel wall. Experiments have shown that modern control techniques like linear quadratic Gaussian (LQG) control require less current than the proportional controller in use at DIII-D when using control coils external to DIII-D’s vacuum vessel. Experiments were conducted to develop control of a rotating n  =  1 perturbation using an LQG controller derived from VALEN and external coils. Feedback using this LQG algorithm outperformed a proportional gain only controller in these perturbation experiments over a range of frequencies. Results from high βN experiments also show that advanced feedback techniques using external control coils may be as effective as internal control coil feedback using classical control techniques.

Social anxiety and the ironic effects of positive interviewer feedback.

PubMed

Budnick, Christopher J; Kowal, Marta; Santuzzi, Alecia M

2015-01-01

Positive interviewer feedback should encourage positive experiences and outcomes for interviewees. Yet, positive feedback is inconsistent with socially anxious interviewees' negative self-views. Socially anxious interviewees might experience increased self-focus while attempting to reconcile the inconsistency between their self-perceptions and that feedback. This could interfere with successful interview performance. This study used a 3 (feedback: positive, negative, no) × 2 (social anxiety: high, low) between-subjects design. Undergraduate students (N = 88) completed a measure of dispositional social anxiety. They then engaged in a simulated interview with a White confederate trained to adhere to a standardized script. Interviewees received positive, negative, or no interviewer feedback. Each interview was video recorded to code anxiety displays, impression management tactics, and interview success. Following positive feedback, socially anxious interviewees displayed more anxiety, less assertiveness, and received lower success ratings. Among anxious interviewees, increased self-focus provided an indirect path between positive feedback and lower success. Consistent with self-verification theory, anxious interviewees had poorer interview performance following positive feedback that contradicted their negative self-views. Thus, socially anxious interviewees might be at a disadvantage when interviewing, especially following positive feedback. Implications for interviewees and interviewers are discussed.

A Proposed Conceptual Framework and Investigation of Upward Feedback Receptivity in Medical Education.

PubMed

Kost, Amanda; Combs, Heidi; Smith, Sherilyn; Klein, Eileen; Kritek, Patricia; Robins, Lynne; Cianciolo, Anna T; Butani, Lavjay; Gigante, Joseph; Ramani, Subha

2015-01-01

WGEA 2015 CONFERENCE ABSTRACT (EDITED). Faculty Perceptions of Receiving Feedback From Third-Year Clerkship Students. Amanda Kost, Heidi Combs, Sherilyn Smith, Eileen Klein, Patricia Kritek, and Lynne Robins. PHENOMENON: In addition to giving feedback to 3rd-year clerkship students, some clerkship instructors receive feedback, requested or spontaneous, from students prior to the clerkship's end. The concept of bidirectional feedback is appealing as a means of fostering a culture of respectful communication and improvement. However, little is known about how teachers perceive this feedback in practice or how it impacts the learning environment. We performed 24 semistructured 30-minute interviews with 3 to 7 attending physician faculty members each in Pediatrics, Internal Medicine, Family Medicine, Surgery, Psychiatry, and Obstetrics and Gynecology who taught in 3rd-year required clerkships during the 2012-2013 academic year. Questions probed teachers' experience with and attitudes toward receiving student feedback. Prompts were used to elicit stories and obtain participant demographics. Interviews were audio-recorded, transcribed, and entered into Dedoose for qualitative analysis. Researchers read transcripts holistically for meaning, designed a coding template, and then independently coded each transcript. A constant comparative approach and regular meetings were used to ensure consistent coding between research team members. Participants ranged in age from 37 to 74, with 5 to 35 years of teaching experience. Seventy-one percent were male, and 83% identified as White. In our preliminary analysis, our informants reported a range of experience in receiving student feedback prior to the end of a clerkship, varying from no experience to having developed mechanisms to regularly request specific feedback about their programs. Most expressed openness to actively soliciting and receiving student feedback on their teaching during the clerkship although many questioned whether this process was feasible. Actual responses to receiving student feedback were mixed. Some reported having received feedback that motivated change, and others rejected the feedback they received on the grounds that it lacked validity or was inappropriate. Others expressed uncertainty about how they would react to student feedback. Faculty expressed a preference for receiving feedback about behaviors and items that were within their control. INSIGHTS: These findings suggest there is opportunity to pilot implementation of a structured student feedback mechanism, separate from teacher evaluations, in selected 3rd-year clerkships. Materials should developed to help faculty solicit, understand, and respond to student feedback and to help students frame and provide the kinds of feedback to teachers that will lead to suggested improvements. Both these endeavors have the potential to improve the clinical learning environment during 3rd-year clerkships through the cultivation of respectful communication and the encouragement of improvement in teaching efforts.

Large-Eddy Simulation of Conductive Flows at Low Magnetic Reynolds Number

NASA Technical Reports Server (NTRS)

Knaepen, B.; Moin, P.

2003-01-01

In this paper we study the LES method with dynamic procedure in the context of conductive flows subject to an applied external magnetic field at low magnetic Reynolds number R(sub m). These kind of flows are encountered in many industrial applications. For example, in the steel industry, applied magnetic fields can be used to damp turbulence in the casting process. In nuclear fusion devices (Tokamaks), liquid-lithium flows are used as coolant blankets and interact with the surrounding magnetic field that drives and confines the fusion plasma. Also, in experimental facilities investigating the dynamo effect, the flow consists of liquid-sodium for which the Prandtl number and, as a consequence, the magnetic Reynolds number is low. Our attention is focused here on the case of homogeneous (initially isotropic) decaying turbulence. The numerical simulations performed mimic the thought experiment described in Moffatt in which an initially homogeneous isotropic conductive flow is suddenly subjected to an applied magnetic field and freely decays without any forcing. Note that this flow was first studied numerically by Schumann. It is well known that in that case, extra damping of turbulence occurs due to the Joule effect and that the flow tends to become progressively independent of the coordinate along the direction of the magnetic field. Our comparison of filtered direct numerical simulation (DNS) predictions and LES predictions show that the dynamic Smagorinsky model enables one to capture successfully the flow with LES, and that it automatically incorporates the effect of the magnetic field on the turbulence. Our paper is organized as follows. In the next section we summarize the LES approach in the case of MHD turbulence at low R(sub m) and recall the definition of the dynamic Smagorinsky model. In Sec. 3 we describe the parameters of the numerical experiments performed and the code used. Section 4 is devoted to the comparison of filtered DNS results and LES results. Conclusions are presented in Sec. 5.

When Feedback Harms and Collaboration Helps in Computer Simulation Environments: An Expertise Reversal Effect

ERIC Educational Resources Information Center

Nihalani, Priya K.; Mayrath, Michael; Robinson, Daniel H.

2011-01-01

We investigated the effects of feedback and collaboration on undergraduates' transfer performance when using a computer networking training simulation. In Experiment 1, 65 computer science "novices" worked through an instructional protocol individually (control), individually with feedback, or collaboratively with feedback. Unexpectedly,…

Accounting Students' Feedback on Feedback in Australian Universities: They're Less than Impressed

ERIC Educational Resources Information Center

Watty, Kim; de Lange, Paul; Carr, Rodney; O'Connell, Brendan; Howieson, Bryan; Jacobsen, Ben

2013-01-01

Undergraduate accounting students in Australian universities are dissatisfied with the feedback that they currently receive. Recent evidence from the Course Experience Questionnaire (CEQ, a national survey of Australian university graduates) suggests that the accounting discipline ranks poorly on assessment feedback when compared to other…

Negative plant-soil feedback predicts tree-species relative abundance in a tropical forest.

PubMed

Mangan, Scott A; Schnitzer, Stefan A; Herre, Edward A; Mack, Keenan M L; Valencia, Mariana C; Sanchez, Evelyn I; Bever, James D

2010-08-05

The accumulation of species-specific enemies around adults is hypothesized to maintain plant diversity by limiting the recruitment of conspecific seedlings relative to heterospecific seedlings. Although previous studies in forested ecosystems have documented patterns consistent with the process of negative feedback, these studies are unable to address which classes of enemies (for example, pathogens, invertebrates, mammals) exhibit species-specific effects strong enough to generate negative feedback, and whether negative feedback at the level of the individual tree is sufficient to influence community-wide forest composition. Here we use fully reciprocal shade-house and field experiments to test whether the performance of conspecific tree seedlings (relative to heterospecific seedlings) is reduced when grown in the presence of enemies associated with adult trees. Both experiments provide strong evidence for negative plant-soil feedback mediated by soil biota. In contrast, above-ground enemies (mammals, foliar herbivores and foliar pathogens) contributed little to negative feedback observed in the field. In both experiments, we found that tree species that showed stronger negative feedback were less common as adults in the forest community, indicating that susceptibility to soil biota may determine species relative abundance in these tropical forests. Finally, our simulation models confirm that the strength of local negative feedback that we measured is sufficient to produce the observed community-wide patterns in tree-species relative abundance. Our findings indicate that plant-soil feedback is an important mechanism that can maintain species diversity and explain patterns of tree-species relative abundance in tropical forests.

Improving the Usefulness and Use of Patient Survey Programs: National Health Service Interview Study

PubMed Central

Darzi, Ara; Gancarczyk, Sarah; Mayer, Erik

2018-01-01

Background A growing body of evidence suggests a concerning lag between collection of patient experience data and its application in service improvement. This study aims to identify what health care staff perceive to be the barriers and facilitators to using patient-reported feedback and showcase successful examples of doing so. Objective This study aimed to apply a systems perspective to suggest policy improvements that could support efforts to use data on the frontlines. Methods Qualitative interviews were conducted in eight National Health Service provider locations in the United Kingdom, which were selected based on National Inpatient Survey scores. Eighteen patient-experience leads were interviewed about using patient-reported feedback with relevant staff. Interviews were transcribed and underwent thematic analysis. Staff-identified barriers and facilitators to using patient experience feedback were obtained. Results The most frequently cited barriers to using patient reported feedback pertained to interpreting results, understanding survey methodology, presentation of data in both national Care Quality Commission and contractor reports, inability to link data to other sources, and organizational structure. In terms of a wish list for improved practice, staff desired more intuitive survey methodologies, the ability to link patient experience data to other sources, and more examples of best practice in patient experience improvement. Three organizations also provided examples of how they successfully used feedback to improve care. Conclusions Staff feedback provides a roadmap for policy makers to reconsider how data is collected and whether or not the national regulations on surveys and patient experience data are meeting the quality improvement needs of local organizations. PMID:29691207

Societe Pluraliste et Diversite des Experiences Spirituelles Chez les Jeunes Adultes: Ce Que Revele Une Enquete=Pluralistic Society and the Diversity of Spiritual Experiences among Young Adults: What One Study Revealed.

ERIC Educational Resources Information Center

Michaud, Claude

1994-01-01

Describes a study conducted at the University of Ottawa to investigate the spiritual experiences of 168 young adults enrolled in the education department in 1992-93 and the impact of those experiences on their personality development. Describes four psycho-religious profiles, including integrated (inductive), conventional (deductive), fragmented…

Comparing Feedback Types in Multimedia Learning of Speech by Young Children With Common Speech Sound Disorders: Research Protocol for a Pretest Posttest Independent Measures Control Trial.

PubMed

Doubé, Wendy; Carding, Paul; Flanagan, Kieran; Kaufman, Jordy; Armitage, Hannah

2018-01-01

Children with speech sound disorders benefit from feedback about the accuracy of sounds they make. Home practice can reinforce feedback received from speech pathologists. Games in mobile device applications could encourage home practice, but those currently available are of limited value because they are unlikely to elaborate "Correct"/"Incorrect" feedback with information that can assist in improving the accuracy of the sound. This protocol proposes a "Wizard of Oz" experiment that aims to provide evidence for the provision of effective multimedia feedback for speech sound development. Children with two common speech sound disorders will play a game on a mobile device and make speech sounds when prompted by the game. A human "Wizard" will provide feedback on the accuracy of the sound but the children will perceive the feedback as coming from the game. Groups of 30 young children will be randomly allocated to one of five conditions: four types of feedback and a control which does not play the game. The results of this experiment will inform not only speech sound therapy, but also other types of language learning, both in general, and in multimedia applications. This experiment is a cost-effective precursor to the development of a mobile application that employs pedagogically and clinically sound processes for speech development in young children.

Comparing Feedback Types in Multimedia Learning of Speech by Young Children With Common Speech Sound Disorders: Research Protocol for a Pretest Posttest Independent Measures Control Trial

PubMed Central

Doubé, Wendy; Carding, Paul; Flanagan, Kieran; Kaufman, Jordy; Armitage, Hannah

2018-01-01

Children with speech sound disorders benefit from feedback about the accuracy of sounds they make. Home practice can reinforce feedback received from speech pathologists. Games in mobile device applications could encourage home practice, but those currently available are of limited value because they are unlikely to elaborate “Correct”/”Incorrect” feedback with information that can assist in improving the accuracy of the sound. This protocol proposes a “Wizard of Oz” experiment that aims to provide evidence for the provision of effective multimedia feedback for speech sound development. Children with two common speech sound disorders will play a game on a mobile device and make speech sounds when prompted by the game. A human “Wizard” will provide feedback on the accuracy of the sound but the children will perceive the feedback as coming from the game. Groups of 30 young children will be randomly allocated to one of five conditions: four types of feedback and a control which does not play the game. The results of this experiment will inform not only speech sound therapy, but also other types of language learning, both in general, and in multimedia applications. This experiment is a cost-effective precursor to the development of a mobile application that employs pedagogically and clinically sound processes for speech development in young children. PMID:29674986

Training voluntary motor suppression with real-time feedback of motor evoked potentials.

PubMed

Majid, D S Adnan; Lewis, Christina; Aron, Adam R

2015-05-01

Training people to suppress motor representations voluntarily could improve response control. We evaluated a novel training procedure of real-time feedback of motor evoked potentials (MEPs) generated by transcranial magnetic stimulation (TMS) over motor cortex. On each trial, a cue instructed participants to use a mental strategy to suppress a particular finger representation without overt movement. A single pulse of TMS was delivered over motor cortex, and an MEP-derived measure of hand motor excitability was delivered visually to the participant within 500 ms. In experiment 1, we showed that participants learned to reduce the excitability of a particular finger beneath baseline (selective motor suppression) within 30 min of practice. In experiment 2, we performed a double-blind study with 2 training groups (1 with veridical feedback and 1 with matched sham feedback) to show that selective motor suppression depends on the veridical feedback itself. Experiment 3 further demonstrated the importance of veridical feedback by showing that selective motor suppression did not arise from mere mental imagery, even when incentivized with reward. Thus participants can use real-time feedback of TMS-induced MEPs to discover an effective mental strategy for selective motor suppression. This high-temporal-resolution, trial-by-trial-feedback training method could be used to help people better control response tendencies and may serve as a potential therapy for motor disorders such as Tourette's and dystonia. Copyright © 2015 the American Physiological Society.

Jumping in aquatic environment after sciatic nerve compression: nociceptive evaluation and morphological characteristics of the soleus muscle of Wistar rats.

PubMed

Malanotte, Jéssica Aline; Kakihata, Camila Mayumi Martin; Karvat, Jhenifer; Brancalhão, Rose Meire Costa; Ribeiro, Lucinéia de Fátima Chasko; Bertolini, Gladson Ricardo Flor

2017-01-01

To evaluate the effect of jumping in aquatic environment on nociception and in the soleus muscle of trained and not trained Wistar rats, in the treatment of compressive neuropathy of the sciatic nerve. Twenty-five Wistar rats were distributed into five groups: Control, Lesion, Trained + Lesion, Lesion + Exercise, and Trained + Lesion + Exercise. The training was jumping exercise in water environment for 20 days prior to injury, and treatment after the injury. Nociception was evaluated in two occasions, before injury and seven after injury. On the last day of the experiment, the right soleus muscles were collected, processed and analyzed as to morphology and morphometry. In the assessment of nociception in the injury site, the Control Group had higher average than the rest, and the Lesion Group was larger than the Trained + Lesion and Lesion + Exercise Groups. The Control Group showed higher nociceptive threshold in paw, compared to the others. In the morphometric analysis, in relation to Control Group, all the injured groups showed decreased muscle fiber area, and in the Lesion Group was lower than in the Lesion + Exercise Group and Trained + Lesion Group. Considering the diameter of the muscle fiber, the Control Group had a higher average than the Trained + Lesion Group and the Trained + Lesion + Exercise Group; and the Lesion Group showed an average lower than the Trained + Lesion and Lesion + Exercise Groups. Resistance exercise produced increased nociception. When performed prior or after nerve damage, it proved effective in avoiding hypotrophy. The combination of the two protocols led to decrease in diameter and area of the muscle fiber. Avaliar os efeitos do salto em meio aquático, na nocicepção e no músculo sóleo, em ratos Wistar treinados e não treinados, no tratamento de neuropatia compressiva do nervo isquiático. Foram distribuídos em cinco grupos 25 ratos Wistar: Controle, Lesão, Treinado + Lesão, Lesão + Exercício e Treinado + Lesão + Exercício. O treino foi com exercício de salto em meio aquático durante 20 dias, prévio à lesão, e o tratamento ocorreu após a lesão. Foram realizadas avaliações da nocicepção, sendo uma pré-lesão e sete pós-lesão. No último dia de experimento, os músculos sóleos direitos foram coletados, processados e analisados por meio de morfologia e morfometria. Na avaliação da nocicepção no local da lesão, o Grupo Controle apresentou média maior que os demais, e o Grupo Lesão foi maior que os Grupos Treinado + Lesão e Lesão + Exercício. O Grupo Controle apresentou limiar nociceptivo na pata maior com relação aos demais. Nas análises morfométricas, em relação ao Grupo Controle, todos os grupos lesionados apresentaram diminuição da área da fibra muscular; o Grupo Lesão apresentou-se menor que os Grupos Treinado + Lesão e Lesão + Exercício. No diâmetro da fibra muscular, o Grupo Controle apresentou média maior que os Grupos Treinado + Lesão e Treinado + Lesão + Exercício, e o Grupo Lesão apresentou média menor que os Grupos Treinado + Lesão e Lesão + Exercício. O exercício físico resistido produziu aumento da nocicepção. Quando realizado previamente ou após a lesão nervosa, mostrou-se eficaz em evitar a hipotrofia. A associação dos dois protocolos levou à diminuição do diâmetro e da área da fibra muscular.

Aerodynamic study of different cyclist positions: CFD analysis and full-scale wind-tunnel tests.

PubMed

Defraeye, Thijs; Blocken, Bert; Koninckx, Erwin; Hespel, Peter; Carmeliet, Jan

2010-05-07

Three different cyclist positions were evaluated with Computational Fluid Dynamics (CFD) and wind-tunnel experiments were used to provide reliable data to evaluate the accuracy of the CFD simulations. Specific features of this study are: (1) both steady Reynolds-averaged Navier-Stokes (RANS) and unsteady flow modelling, with more advanced turbulence modelling techniques (Large-Eddy Simulation - LES), were evaluated; (2) the boundary layer on the cyclist's surface was resolved entirely with low-Reynolds number modelling, instead of modelling it with wall functions; (3) apart from drag measurements, also surface pressure measurements on the cyclist's body were performed in the wind-tunnel experiment, which provided the basis for a more detailed evaluation of the predicted flow field by CFD. The results show that the simulated and measured drag areas differed about 11% (RANS) and 7% (LES), which is considered to be a close agreement in CFD studies. A fair agreement with wind-tunnel data was obtained for the predicted surface pressures, especially with LES. Despite the higher accuracy of LES, its much higher computational cost could make RANS more attractive for practical use in some situations. CFD is found to be a valuable tool to evaluate the drag of different cyclist positions and to investigate the influence of small adjustments in the cyclist's position. A strong advantage of CFD is that detailed flow field information is obtained, which cannot easily be obtained from wind-tunnel tests. This detailed information allows more insight in the causes of the drag force and provides better guidance for position improvements. Copyright 2010 Elsevier Ltd. All rights reserved.

Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

NASA Astrophysics Data System (ADS)

Leger, Michel T.

Les activites humaines energivores telles l'utilisation intensive de l'automobile, la surconsommation de biens et l'usage excessif d'electricite contribuent aux changements climatiques et autres problemes environnementaux. Bien que plusieurs recherches rapportent que l'etre humain est de plus en plus conscient de ses impacts sur le climat de la planete, ces memes recherches indiquent qu'en general, les gens continuent a se comporter de facon non ecologique. Que ce soit a l'ecole ou dans la communaute, plusieurs chercheurs en education relative a l'environnement estiment qu'une personne bien intentionnee est capable d'adopter des comportements plus respectueux de l'environnement. Le but de cette these etait de comprendre le processus d'integration de comportements d'attenuation des changements climatiques dans des familles. A cette fin, nous nous sommes fixe deux objectifs : 1) decrire les competences et les procedes qui favorisent l'adoption de comportements d'attenuation des changements climatiques dans des familles et 2) decrire les facteurs et les dynamiques familiales qui facilitent et limitent l'adoption de comportements d'attenuation des changements climatiques dans des familles. Des familles ont ete invitees a essayer des comportements personnels et collectifs d'attenuation des changements climatiques de sorte a integrer des modes de vie plus ecologiques. Sur une periode de huit mois, nous avons suivi leur experience de changement afin de mieux comprendre comment se produit le processus de changement dans des familles qui decident volontairement d'adopter des comportements d'attenuation des changements climatiques. Apres leur avoir fourni quelques connaissances de base sur les changements climatiques, nous avons observe le vecu de changement des familles durant huit mois d'essais a l'aide de journaux reflexifs, d'entretiens d'explicitation et du journal du chercheur. La these comporte trois articles scientifiques. Dans le premier article, nous presentons une recension des ecrits sur le changement de comportement en environnement. Nous explorons egalement la famille comme systeme fonctionnel de sorte a mieux comprendre ce contexte d'action environnementale qui est, a notre connaissance, peu etudie. Dans le deuxieme article, nous presentons nos resultats de recherche concernant les facteurs d'influence observes ainsi que les competences manifestees au cours du processus d'adoption de nouveaux comportements environnementaux dans trois familles. Enfin, le troisieme article presente les resultats du cas d'une quatrieme famille ou les membres vivent depuis longtemps des modes de vie ecologique. Dans le cadre d'une demarche d'analyse par theorisation ancree, l'etude de ce cas modele nous a permis d'approfondir les categories conceptuelles identifiees dans le deuxieme article de sorte a produire une modelisation de l'integration de comportements environnementaux dans le contexte de la famille. Les conclusions degagees grace a la recension des ecrits nous ont permis d'identifier les elements qui pourraient influencer l'adoption de comportements environnementaux dans des familles. La recension a aussi permis une meilleure comprehension des divers facteurs qui peuvent affecter l'adoption de comportements environnementaux et, enfin, elle a permis de mieux cerner le phenomene de changement de comportement dans le contexte de la famille consideree comme un systeme. En appliquant un processus d'analyse inductif, a partir de nos donnees qualitatives, les resultats de notre etude multi-cas nous ont indique que deux construits conceptuels semblent influencer l'adoption de comportements environnementaux en famille : 1) les valeurs biospheriques communes au sein de la famille et 2) les competences collectivement mises a profit collectivement durant l'essai de nouveaux comportements environnementaux. Notre modelisation du processus de changement dans des familles indique aussi qu'une dynamique familiale collaborative et la presence d'un groupe de soutien exterieur sont deux elements conceptuels qui tendent a influencer les deux principaux construits et, par ce fait, tendent a augmenter les chances d'integrer de nouveaux comportements environnementaux dans des familles. En conclusion, nous presentons les limites de notre recherche ainsi que des pistes pour des recherches futures. Notamment, nous recommandons que l'ecole accueille les familles des eleves dans le cadre d'activites d'education a l'environnement ou les freres, les soeurs et les parents des eleves puissent apprendre ensemble, a l'ecole. Par exemple, nous recommandons la conduite en ERE d'une recherche action portant sur l'apprentissage intergenerationnel de nouveaux comportements dans le contexte de la famille. Mots-cles : education relative a l'environnement, comportement environnemental en famille, changement de comportement en famille, valeurs biospheriques, competences d'action.

Blocked versus randomized presentation modes differentially modulate feedback-related negativity and P3b amplitudes.

PubMed

Pfabigan, Daniela M; Zeiler, Michael; Lamm, Claus; Sailer, Uta

2014-04-01

Electrophysiological studies on feedback processing typically use a wide range of feedback stimuli which might not always be comparable. The current study investigated whether two indicators of feedback processing - feedback-related negativity (FRN) and P3b - differ for feedback stimuli with explicit (facial expressions) or assigned valence information (symbols). In addition, we assessed whether presenting feedback in either a trial-by-trial or a block-wise fashion affected these ERPs. EEG was recorded in three experiments while participants performed a time estimation task and received two different types of performance feedback. Only P3b amplitudes varied consistently in response to feedback type for both presentation types. Moreover, the blocked feedback type presentation yielded more distinct FRN peaks, higher effect sizes, and a significant relation between FRN amplitudes and behavioral task performance measures. Both stimulus type and presentation mode may provoke systematic changes in feedback-related ERPs. The current findings point at important potential confounds that need to be controlled for when designing FRN or P3b studies. Studies investigating P3b amplitudes using mixed types of stimuli have to be interpreted with caution. Furthermore, we suggest implementing a blocked presentation format when presenting different feedback types within the same experiment. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Suspicion of Motives Predicts Minorities' Responses to Positive Feedback in Interracial Interactions.

PubMed

Major, Brenda; Kunstman, Jonathan W; Malta, Brenna D; Sawyer, Pamela J; Townsend, Sarah S M; Mendes, Wendy Berry

2016-01-01

Strong social and legal norms in the United States discourage the overt expression of bias against ethnic and racial minorities, increasing the attributional ambiguity of Whites' positive behavior to ethnic minorities. Minorities who suspect that Whites' positive overtures toward minorities are motivated more by their fear of appearing racist than by egalitarian attitudes may regard positive feedback they receive from Whites as disingenuous. This may lead them to react to such feedback with feelings of uncertainty and threat. Three studies examined how suspicion of motives relates to ethnic minorities' responses to receiving positive feedback from a White peer or same-ethnicity peer (Experiment 1), to receiving feedback from a White peer that was positive or negative (Experiment 2), and to receiving positive feedback from a White peer who did or did not know their ethnicity (Experiment 3). As predicted, the more suspicious Latinas were of Whites' motives for behaving positively toward minorities in general, the more they regarded positive feedback from a White peer who knew their ethnicity as disingenuous and the more they reacted with cardiovascular reactivity characteristic of threat/avoidance, increased feelings of stress, heightened uncertainty, and decreased self-esteem. We discuss the implications for intergroup interactions of perceptions of Whites' motives for nonprejudiced behavior.

Making and monitoring errors based on altered auditory feedback

PubMed Central

Pfordresher, Peter Q.; Beasley, Robertson T. E.

2014-01-01

Previous research has demonstrated that altered auditory feedback (AAF) disrupts music performance and causes disruptions in both action planning and the perception of feedback events. It has been proposed that this disruption occurs because of interference within a shared representation for perception and action (Pfordresher, 2006). Studies reported here address this claim from the standpoint of error monitoring. In Experiment 1 participants performed short melodies on a keyboard while hearing no auditory feedback, normal auditory feedback, or alterations to feedback pitch on some subset of events. Participants overestimated error frequency when AAF was present but not for normal feedback. Experiment 2 introduced a concurrent load task to determine whether error monitoring requires executive resources. Although the concurrent task enhanced the effect of AAF, it did not alter participants’ tendency to overestimate errors when AAF was present. A third correlational study addressed whether effects of AAF are reduced for a subset of the population who may lack the kind of perception/action associations that lead to AAF disruption: poor-pitch singers. Effects of manipulations similar to those presented in Experiments 1 and 2 were reduced for these individuals. We propose that these results are consistent with the notion that AAF interference is based on associations between perception and action within a forward internal model of auditory-motor relationships. PMID:25191294

Suppression of ENSO in a coupled model without water vapor feedback

NASA Astrophysics Data System (ADS)

Hall, A.; Manabe, S.

We examine 800-year time series of internally generated variability in both a coupled ocean-atmosphere model where water vapor anomalies are not allowed to interact with longwave radiation and one where they are. The ENSO-like phenomenon in the experiment without water vapor feedback is drastically suppressed both in amplitude and geographic extent relative to the experiment with water vapor feedback. Surprisingly, the reduced amplitude of ENSO-related sea surface temperature anomalies in the model without water vapor feedback cannot be attributed to greater longwave damping of sea surface temperature. (Differences between the two experiments in radiative feedback due to clouds counterbalance almost perfectly the differences in radiative feedback due to water vapor.) Rather, the interaction between water vapor anomalies and longwave radiation affects the ENSO-like phenomenon through its influence on the vertical structure of radiative heating: Because of the changes in water vapor associated with it, a given warm equatorial Pacific sea surface temperature anomaly is associated with a radiative heating profile that is much more gravitationally unstable when water vapor feedback is present. The warm sea surface temperature anomaly therefore results in more convection in the experiment with water vapor feedback. The increased convection, in turn, is related to a larger westerly wind-stress anomaly, which creates a larger decrease in upwelling of cold water, thereby enhancing the magnitude of the original warm sea surface temperature anomaly. In this manner, the interaction between water vapor anomalies and longwave radiation magnifies the air-sea interactions at the heart of the ENSO phenomenon; without this interaction, the coupling between sea surface temperature and wind stress is effectively reduced, resulting in smaller amplitude ENSO episodes with a more limited geographical extent.

Simulation and design of feedback control on resistive wall modes in Keda Torus eXperiment

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

Li, Chenguang; Liu, Wandong; Li, Hong

2014-12-15

The feedback control of resistive wall modes (RWMs) in Keda Torus eXperiment (KTX) (Liu et al., Plasma Phys. Controlled Fusion 56, 094009 (2014)) is investigated by simulation. A linear model is built to describe the growth of the unstable modes in the absence of feedback and the resulting mode suppression due to feedback, given the typical reversed field pinch plasma equilibrium. The layout of KTX with two shell structures (the vacuum vessel and the stabilizing shell) is taken into account. The feedback performance is explored both in the scheme of “clean mode control” (Zanca et al., Nucl. Fusion 47, 1425more » (2007)) and “raw mode control.” The discrete time control model with specific characteristic times will mimic the real feedback control action and lead to the favored control cycle. Moreover, the conceptual design of feedback control system is also presented, targeting on both RWMs and tearing modes.« less

Negative plant-phyllosphere feedbacks in native Asteraceae hosts - a novel extension of the plant-soil feedback framework.

PubMed

Whitaker, Briana K; Bauer, Jonathan T; Bever, James D; Clay, Keith

2017-08-01

Over the past 25 years, the plant-soil feedback (PSF) framework has catalyzed our understanding of how belowground microbiota impact plant fitness and species coexistence. Here, we apply a novel extension of this framework to microbiota associated with aboveground tissues, termed 'plant-phyllosphere feedback (PPFs)'. In parallel greenhouse experiments, rhizosphere and phyllosphere microbiota of con- and heterospecific hosts from four species were independently manipulated. In a third experiment, we tested the combined effects of soil and phyllosphere feedback under field conditions. We found that three of four species experienced weak negative PSF whereas, in contrast, all four species experienced strong negative PPFs. Field-based feedback estimates were highly negative for all four species, though variable in magnitude. Our results suggest that phyllosphere microbiota, like rhizosphere microbiota, can potentially mediate plant species coexistence via negative feedbacks. Extension of the PSF framework to the phyllosphere is needed to more fully elucidate plant-microbiota interactions. © 2017 John Wiley & Sons Ltd/CNRS.

Implementing a Measurement Feedback System: A Tale of Two Sites

PubMed Central

Douglas, Susan R.; Vides De Andrade, Ana Regina; Tomlinson, Michele; Gleacher, Alissa; Olin, Serene; Hoagwood, Kimberly

2015-01-01

A randomized experiment was conducted in two outpatient clinics evaluating a measurement feedback system called contextualized feedback systems. The clinicians of 257 Youth 11–18 received feedback on progress in mental health symptoms and functioning either every 6 months or as soon as the youth’s, clinician’s or caregiver’s data were entered into the system. The ITT analysis showed that only one of the two participating clinics (Clinic R) had an enhanced outcome because of feedback, and only for the clinicians’ ratings of youth symptom severity on the SFSS. A dose–response effect was found only for Clinic R for both the client and clinician ratings. Implementation analyses showed that Clinic R had better implementation of the feedback intervention. Clinicians’ questionnaire completion rate and feedback viewing at Clinic R were 50 % higher than clinicians at Clinic U. The discussion focused on the differences in implementation at each site and how these differences may have contributed to the different outcomes of the experiment. PMID:25876736

Progress Feedback Effects on Students' Writing Mastery Goal, Self-Efficacy Beliefs, and Performance

ERIC Educational Resources Information Center

Duijnhouwer, Hendrien; Prins, Frans J.; Stokking, Karel M.

2010-01-01

The effects of progress feedback on university students' writing mastery goal, self-efficacy beliefs, and writing performance were examined in this experiment. Students in the experimental condition (n = 42) received progress feedback on their writing assignment, whereas students in the control condition (n = 44) received feedback without progress…

Effects of Differential Feedback on Students' Examination Performance

ERIC Educational Resources Information Center

Lipnevich, Anastasiya A.; Smith, Jeffrey K.

2009-01-01

The effects of feedback on performance and factors associated with it were examined in a large introductory psychology course. The experiment involved college students (N = 464) working on an essay examination under 3 conditions: no feedback, detailed feedback that was perceived by participants to be provided by the course instructor, and detailed…

"Look at My Drawing!"

ERIC Educational Resources Information Center

Wilson, Maja

2012-01-01

Every student experiences feedback in different ways, and there is a real trick to knowing when no feedback is needed. Feedback of any kind can sometimes paralyze a student, interrupting the flow of his or her work. Teachers need to understand and recognize when and why this happens. The author's sketch of three goals for giving feedback in this…

Sounds Good: Using Digital Audio for Evaluation Feedback

ERIC Educational Resources Information Center

Rotheram, Bob

2009-01-01

Feedback on student work is problematic for faculty and students in British higher education. Evaluation feedback takes faculty much time to produce and students are often dissatisfied with its quantity, timing, and clarity. The Sounds Good project has been experimenting with the use of digital audio for feedback, aiming to save faculty time and…

Enhancing the Impact of Formative Feedback on Student Learning through an Online Feedback System

ERIC Educational Resources Information Center

Hatziapostolou, Thanos; Paraskakis, Iraklis

2010-01-01

Formative feedback is instrumental in the learning experience of a student. It can be effective in promoting learning if it is timely, personal, manageable, motivational, and in direct relation with assessment criteria. Despite its importance, however, research suggests that students are discouraged from engaging in the feedback process primarily…

Optimizing electricity consumption: A case of function learning.

PubMed

Guath, Mona; Millroth, Philip; Juslin, Peter; Elwin, Ebba

2015-12-01

A popular way to improve consumers' control over their electricity consumption is by providing outcome feedback on the cost with in-home displays. Research on function learning, however, suggests that outcome feedback may not always be ideal for learning, especially if the feedback signal is noisy. In this study, we relate research on function learning to in-home displays and use a laboratory task simulating a household to investigate the role of outcome feedback and function learning on electricity optimization. Three function training schemes (FTSs) are presented that convey specific properties of the functions that relate the electricity consumption to the utility and cost. In Experiment 1, we compared learning from outcome feedback with 3 FTSs, 1 of which allowed maximization of the utility while keeping the budget, despite no feedback about the total monthly cost. In Experiment 2, we explored the combination of this FTS and outcome feedback. The results suggested that electricity optimization may be facilitated if feedback learning is preceded by a brief period of function training. (c) 2015 APA, all rights reserved).

Relational interaction in occupational therapy: Conversation analysis of positive feedback.

PubMed

Weiste, Elina

2018-01-01

The therapeutic relationship is an important factor for good therapy outcomes. The primary mediator of a beneficial therapy relationship is clinician-client interaction. However, few studies identify the observable interactional attributes of good quality relational interactions, e.g. offering the client positive feedback. The present paper aims to expand current understanding of relational interaction by analyzing the real-time interactional practices therapists use for offering positive feedback, an important value in occupational therapy. The analysis is based on the conversation analysis of 15 video-recorded occupational therapy encounters in psychiatric outpatient clinics. Two types of positive feedback were identified. In aligning feedback, therapists encouraged and complimented clients' positive perspectives on their own achievements in adopting certain behaviour, encouraging and supporting their progress. In redirecting feedback, therapists shifted the perspective from clients' negative experiences to their positive experiences. This shift was interactionally successful if they laid the foundation for the shift in perspective and attuned their expressions to the clients' emotional states. Occupational therapists routinely provide their clients with positive feedback. Awareness of the interactional attributes related to positive feedback is critically important for successful relational interaction.

When do counterstereotypic ingroup members inspire versus deflate? The effect of successful professional women on young women's leadership self-concept.

PubMed

Asgari, Shaki; Dasgupta, Nilanjana; Stout, Jane G

2012-03-01

Three experiments tested whether and when exposure to counterstereotypic ingroup members enhances women's implicit leadership self-concept. Participants read about professional women leaders framed as similar to versus different from most women (Experiment 1) or having the same versus different collegiate background as participants (Experiment 3). Experiment 2 manipulated similarity by giving false feedback about participants' similarity to women leaders. In all cases, seeing women leaders reduced implicit self-stereotyping relative to controls but only when they were portrayed as similar to one's ingroup (Experiment 1) and oneself (Experiments 2-3). Leaders portrayed as dissimilar either had no effect on self-beliefs (Experiment 1 and 3) or increased implicit self-stereotyping (Experiment 2). Dissimilar leaders also deflated participants' career goals and explicit leadership beliefs (Experiment 3). Finally, implicit self-beliefs became less stereotypic regardless of whether women believed the similarity feedback, but explicit self-beliefs changed only when they believed the feedback to be true (Experiment 2).

Stuttering adults' lack of pre-speech auditory modulation normalizes when speaking with delayed auditory feedback.

PubMed

Daliri, Ayoub; Max, Ludo

2018-02-01

Auditory modulation during speech movement planning is limited in adults who stutter (AWS), but the functional relevance of the phenomenon itself remains unknown. We investigated for AWS and adults who do not stutter (AWNS) (a) a potential relationship between pre-speech auditory modulation and auditory feedback contributions to speech motor learning and (b) the effect on pre-speech auditory modulation of real-time versus delayed auditory feedback. Experiment I used a sensorimotor adaptation paradigm to estimate auditory-motor speech learning. Using acoustic speech recordings, we quantified subjects' formant frequency adjustments across trials when continually exposed to formant-shifted auditory feedback. In Experiment II, we used electroencephalography to determine the same subjects' extent of pre-speech auditory modulation (reductions in auditory evoked potential N1 amplitude) when probe tones were delivered prior to speaking versus not speaking. To manipulate subjects' ability to monitor real-time feedback, we included speaking conditions with non-altered auditory feedback (NAF) and delayed auditory feedback (DAF). Experiment I showed that auditory-motor learning was limited for AWS versus AWNS, and the extent of learning was negatively correlated with stuttering frequency. Experiment II yielded several key findings: (a) our prior finding of limited pre-speech auditory modulation in AWS was replicated; (b) DAF caused a decrease in auditory modulation for most AWNS but an increase for most AWS; and (c) for AWS, the amount of auditory modulation when speaking with DAF was positively correlated with stuttering frequency. Lastly, AWNS showed no correlation between pre-speech auditory modulation (Experiment II) and extent of auditory-motor learning (Experiment I) whereas AWS showed a negative correlation between these measures. Thus, findings suggest that AWS show deficits in both pre-speech auditory modulation and auditory-motor learning; however, limited pre-speech modulation is not directly related to limited auditory-motor adaptation; and in AWS, DAF paradoxically tends to normalize their otherwise limited pre-speech auditory modulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Feedback in clinical education, part I: Characteristics of feedback provided by approved clinical instructors.

PubMed

Nottingham, Sara; Henning, Jolene

2014-01-01

Providing students with feedback is an important component of athletic training clinical education; however, little information is known about the feedback that Approved Clinical Instructors (ACIs; now known as preceptors) currently provide to athletic training students (ATSs). To characterize the feedback provided by ACIs to ATSs during clinical education experiences. Qualitative study. One National Collegiate Athletic Association Division I athletic training facility and 1 outpatient rehabilitation clinic that were clinical sites for 1 entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. A total of 4 ACIs with various experience levels and 4 second-year ATSs. Extensive field observations were audio recorded, transcribed, and integrated with field notes for analysis. The constant comparative approach of open, axial, and selective coding was used to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. The ACIs gave 88 feedback statements in 45 hours and 10 minutes of observation. Characteristics of feedback categories included purpose, timing, specificity, content, form, and privacy. Feedback that ACIs provided included several components that made each feedback exchange unique. The ACIs in our study provided feedback that is supported by the literature, suggesting that ACIs are using current recommendations for providing feedback. Feedback needs to be investigated across multiple athletic training education programs to gain more understanding of certain areas of feedback, including frequency, privacy, and form.

General practitioners' and students' experiences with feedback during a six-week clerkship in general practice: a qualitative study.

PubMed

Gran, Sarah Frandsen; Brænd, Anja Maria; Lindbæk, Morten; Frich, Jan C

2016-06-01

Feedback may be scarce and unsystematic during students' clerkship periods. We wanted to explore general practitioners' (GPs) and medical students' experiences with giving and receiving supervision and feedback during a clerkship in general practice, with a focus on their experiences with using a structured tool (StudentPEP) to facilitate feedback and supervision. Qualitative study. Teachers and students from a six-week clerkship in general practice for fifth year medical students were interviewed in two student and two teacher focus groups. 21 GPs and nine medical students. We found that GPs first supported students' development in the familiarization phase by exploring the students' expectations and competency level. When mutual trust had been established through the familiarization phase GPs encouraged students to conduct their own consultations while being available for supervision and feedback. Both students and GPs emphasized that good feedback promoting students' professional development was timely, constructive, supportive, and focused on ways to improve. Among the challenges GPs mentioned were giving feedback on behavioral issues such as body language and insensitive use of electronic devices during consultations or if the student was very insecure, passive, and reluctant to take action or lacked social or language skills. While some GPs experienced StudentPEP as time-consuming and unnecessary, others argued that the tool promoted feedback and learning through mandatory observations and structured questions. Mutual trust builds a learning environment in which supervision and feedback may be given during students' clerkship in general practice. Structured tools may promote feedback, reflection and learning. Key Points Observing the teacher and being supervised are essential components of Medical students' learning during general practice clerkships. Teachers and students build mutual trust in the familiarization phase. Good feedback is based on observations, is timely, encouraging, and instructive. StudentPEP may create an arena for structured feedback and reflection.

Submarine landslides: advances and challenges

USGS Publications Warehouse

Locat, Jacques; Lee, Homa J.

2002-01-01

Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarinemass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors. Key words : submarine slides, hazards, risk assessment, morphology, mobility, tsunami. Le dveloppement rcent de techniques de levs hydrograhiques pour les fonds marins nous a permis d'atteindre une qualit ingale dans la cartographie et la description des glissements sous marins. l'exception des courants de turbidit, on retrouve dans le domaine aquatique les mmes types de mouvements de terrain que sur terre. Par contre, les glissements sous-marins peuvent atteindre des distances excdant 100 km de telle sorte que leur impact sur les activits offshore doit tre pris en compte sur degrandes tendues. La grande mobilit des glissements sous-marins n'est pas encore bien comprise, comme pour le cas des coules dedbris cartographies sur le cne du Mississippi ainsi que pour les grandes avalanches rocheuses sous-marines retrouves au pourtour des les volcaniques. Un dfi majeur auquel nous faisons face est celui de dterminer les alas associs aux divers types demouvements sous-marins ainsi que les risques associs l'activit humaine, telle que l'exploitation des ressources naturelles et l'tablissement de routes de communications fiables. Mots cls : glissements sous-marins, morphologie, ala, risque, mobilit, tsunami.

DNS and LES of a Shear-Free Mixing Layer

NASA Technical Reports Server (NTRS)

Knaepen, B.; Debliquy, O.; Carati, D.

2003-01-01

The purpose of this work is twofold. First, given the computational resources available today, it is possible to reach, using DNS, higher Reynolds numbers than in Briggs et al.. In the present study, the microscale Reynolds numbers reached in the low- and high-energy homogeneous regions are, respectively, 32 and 69. The results reported earlier can thus be complemented and their robustness in the presence of increased turbulence studied. The second aim of this work is to perform a detailed and documented LES of the shear-free mixing layer. In that respect, the creation of a DNS database at higher Reynolds number is necessary in order to make meaningful LES assessments. From the point of view of LES, the shear-free mixing-layer is interesting since it allows one to test how traditional LES models perform in the presence of an inhomogeneity without having to deal with difficult numerical issues. Indeed, as argued in Briggs et al., it is possible to use a spectral code to study the shear-free mixing layer and one can thus focus on the accuracy of the modelling while avoiding contamination of the results by commutation errors etc. This paper is organized as follows. First we detail the initialization procedure used in the simulation. Since the flow is not statistically stationary, this initialization procedure has a fairly strong influence on the evolution. Although we will focus here on the shear-free mixing layer, the method proposed in the present work can easily be used for other flows with one inhomogeneous direction. The next section of the article is devoted to the description of the DNS. All the relevant parameters are listed and comparison with the Veeravalli & Warhaft experiment is performed. The section on the LES of the shear-free mixing layer follows. A detailed comparison between the filtered DNS data and the LES predictions is presented. It is shown that simple eddy viscosity models perform very well for the present test case, most probably because the flow seems to be almost isotropic in the small-scale range that is not resolved by the LES.

Development of a Hybrid RANS/LES Method for Turbulent Mixing Layers

NASA Technical Reports Server (NTRS)

Georgiadis, Nicholas J.; Alexander, J. Iwan D.; Reshotko, Eli

2001-01-01

Significant research has been underway for several years in NASA Glenn Research Center's nozzle branch to develop advanced computational methods for simulating turbulent flows in exhaust nozzles. The primary efforts of this research have concentrated on improving our ability to calculate the turbulent mixing layers that dominate flows both in the exhaust systems of modern-day aircraft and in those of hypersonic vehicles under development. As part of these efforts, a hybrid numerical method was recently developed to simulate such turbulent mixing layers. The method developed here is intended for configurations in which a dominant structural feature provides an unsteady mechanism to drive the turbulent development in the mixing layer. Interest in Large Eddy Simulation (LES) methods have increased in recent years, but applying an LES method to calculate the wide range of turbulent scales from small eddies in the wall-bounded regions to large eddies in the mixing region is not yet possible with current computers. As a result, the hybrid method developed here uses a Reynolds-averaged Navier-Stokes (RANS) procedure to calculate wall-bounded regions entering a mixing section and uses a LES procedure to calculate the mixing-dominated regions. A numerical technique was developed to enable the use of the hybrid RANS-LES method on stretched, non-Cartesian grids. With this technique, closure for the RANS equations is obtained by using the Cebeci-Smith algebraic turbulence model in conjunction with the wall-function approach of Ota and Goldberg. The LES equations are closed using the Smagorinsky subgrid scale model. Although the function of the Cebeci-Smith model to replace all of the turbulent stresses is quite different from that of the Smagorinsky subgrid model, which only replaces the small subgrid turbulent stresses, both are eddy viscosity models and both are derived at least in part from mixing-length theory. The similar formulation of these two models enables the RANS and LES equations to be solved with a single solution scheme and computational grid. The hybrid RANS-LES method has been applied to a benchmark compressible mixing layer experiment in which two isolated supersonic streams, separated by a splitter plate, provide the flows to a constant-area mixing section. Although the configuration is largely two dimensional in nature, three-dimensional calculations were found to be necessary to enable disturbances to develop in three spatial directions and to transition to turbulence. The flow in the initial part of the mixing section consists of a periodic vortex shedding downstream of the splitter plate trailing edge. This organized vortex shedding then rapidly transitions to a turbulent structure, which is very similar to the flow development observed in the experiments. Although the qualitative nature of the large-scale turbulent development in the entire mixing section is captured well by the LES part of the current hybrid method, further efforts are planned to directly calculate a greater portion of the turbulence spectrum and to limit the subgrid scale modeling to only the very small scales. This will be accomplished by the use of higher accuracy solution schemes and more powerful computers, measured both in speed and memory capabilities.

Bridging the Transition from Mesoscale to Microscale Turbulence in Numerical Weather Prediction Models

NASA Astrophysics Data System (ADS)

Muñoz-Esparza, Domingo; Kosović, Branko; Mirocha, Jeff; van Beeck, Jeroen

2014-12-01

With a focus towards developing multiscale capabilities in numerical weather prediction models, the specific problem of the transition from the mesoscale to the microscale is investigated. For that purpose, idealized one-way nested mesoscale to large-eddy simulation (LES) experiments were carried out using the Weather Research and Forecasting model framework. It is demonstrated that switching from one-dimensional turbulent diffusion in the mesoscale model to three-dimensional LES mixing does not necessarily result in an instantaneous development of turbulence in the LES domain. On the contrary, very large fetches are needed for the natural transition to turbulence to occur. The computational burden imposed by these long fetches necessitates the development of methods to accelerate the generation of turbulence on a nested LES domain forced by a smooth mesoscale inflow. To that end, four new methods based upon finite amplitude perturbations of the potential temperature field along the LES inflow boundaries are developed, and investigated under convective conditions. Each method accelerated the development of turbulence within the LES domain, with two of the methods resulting in a rapid generation of production and inertial range energy content associated to microscales that is consistent with non-nested simulations using periodic boundary conditions. The cell perturbation approach, the simplest and most efficient of the best performing methods, was investigated further under neutral and stable conditions. Successful results were obtained in all the regimes, where satisfactory agreement of mean velocity, variances and turbulent fluxes, as well as velocity and temperature spectra, was achieved with reference non-nested simulations. In contrast, the non-perturbed LES solution exhibited important energy deficits associated to a delayed establishment of fully-developed turbulence. The cell perturbation method has negligible computational cost, significantly accelerates the generation of realistic turbulence, and requires minimal parameter tuning, with the necessary information relatable to mean inflow conditions provided by the mesoscale solution.

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

Pluquet, Alain

Cette théetudie les techniques d'identication de l'electron dans l'experience D0 au laboratoire Fermi pres de Chicago Le premier chapitre rappelle quelques unes des motivations physiques de l'experience physique des jets physique electrofaible physique du quark top Le detecteur D0 est decrit en details dans le second chapitre Le troisieme cha pitre etudie les algorithmes didentication de lelectron trigger reconstruction ltres et leurs performances Le quatrieme chapitre est consacre au detecteur a radiation de transition TRD construit par le Departement dAstrophysique Physique des Particules Physique Nucleaire et dInstrumentation Associee de Saclay il presente son principe sa calibration et ses performances Ennmore » le dernier chapitre decrit la methode mise au point pour lanalyse des donnees avec le TRD et illustre son emploi sur quelques exemples jets simulant des electrons recherche du quark top« less

Small Angle Neutron Scattering experiments on ``side-on fixed"" liquid crystal polyacrylates

NASA Astrophysics Data System (ADS)

Leroux, N.; Keller, P.; Achard, M. F.; Noirez, L.; Hardouin, F.

1993-08-01

Small Angle Neutron Scattering experiments were carried out on liquid crystalline “side-on fixed” polyacrylates : we observe that the polymer backbone adopts a prolate conformation in the nematic phase. Such anisotropy of the global backbone is larger for smaller spacer length. In every case we measure at low temperatures a large chain extension as previously described in polysiloxanes. Par diffusion des neutrons aux petits angles nous observons que la chaîne de polyacrylates “en haltère” adopte une conformation type prolate en phase nématique. Son anisotropie est d'autant plus grande que l'espaceur est plus court. Dans tous les cas, nous retrouvons à basse température la forte extension de la chaîne polymère qui fut d'abord révélée dans les polysiloxanes.

Assessment of sub-grid scale dispersion closure with regularized deconvolution method in a particle-laden turbulent jet

NASA Astrophysics Data System (ADS)

Wang, Qing; Zhao, Xinyu; Ihme, Matthias

2017-11-01

Particle-laden turbulent flows are important in numerous industrial applications, such as spray combustion engines, solar energy collectors etc. It is of interests to study this type of flows numerically, especially using large-eddy simulations (LES). However, capturing the turbulence-particle interaction in LES remains challenging due to the insufficient representation of the effect of sub-grid scale (SGS) dispersion. In the present work, a closure technique for the SGS dispersion using regularized deconvolution method (RDM) is assessed. RDM was proposed as the closure for the SGS dispersion in a counterflow spray that is studied numerically using finite difference method on a structured mesh. A presumed form of LES filter is used in the simulations. In the present study, this technique has been extended to finite volume method with an unstructured mesh, where no presumption on the filter form is required. The method is applied to a series of particle-laden turbulent jets. Parametric analyses of the model performance are conducted for flows with different Stokes numbers and Reynolds numbers. The results from LES will be compared against experiments and direct numerical simulations (DNS).

Bob Meyer (right), acting deputy director of NASA Dryden, shakes hands with Les Bordelon, executive

NASA Technical Reports Server (NTRS)

2002-01-01

Bob Meyer (on the right), acting deputy director of NASA's Dryden Flight Research Center, Edwards, California, shakes hands with Les Bordelon, executive director of Edwards Air Force Base. The handshake represents Dryden's acceptance of an Air Force C-20A delivered from Ramstein Air Base, Germany. The aircraft will be modified to carry equipment and experiments in support of both NASA and U.S. Air Force projects. The joint use of this aircraft is a result of the NASA Dryden/Edwards Air Force Base Alliance which shares some resources as cost-cutting measures.

Vortex Breakdown over Slender Delta Wings (Eclatement tourbillonnaire sur les ailes delta effil es)

DTIC Science & Technology

2009-11-01

flow patterns for a) experiments of Mitchell et. al ., b) grid G9A4 fully 15-12 turbulent, c) grid G9A4 laminar to turbulent transition at 30% root...tourbillonnaires et en particulier les tourbillons de bord d’attaque subissent une désorganisation soudaine connue sous le nom de rupture du vortex. Ce...attack in the range of –10° to 36°, an amplitude of 5° to 26° and an oscillation frequency of 0.2 to 1.5 Hz. 8) TPI Test Case De Luca et al . tested a

Achalasia.

PubMed

Islam, Saleem

2017-04-01

Achalasia is a rare neurogenic motility disorder of the esophagus, occurring in approximately 0.11 cases per 100,000 children. The combination of problems (aperistalsis, hypertensive lower esophageal sphincter (LES), and lack of receptive LES relaxation) results in patients having symptoms of progressive dysphagia, weight loss, and regurgitation. Treatment modalities have evolved over the past few decades from balloon dilation and botulinum toxin injection to laparoscopic Heller myotomy and endoscopic myotomy. Most data on achalasia management is extrapolated to children from adult experience. This article describes understanding of the pathogenesis and discusses newer therapeutic techniques as well as controversies in management. Copyright © 2017 Elsevier Inc. All rights reserved.

The experience of bedaquiline implementation at a decentralised clinic in South Africa.

PubMed

Cariem, R; Cox, V; de Azevedo, V; Hughes, J; Mohr, E; Durán, L Triviño; Ndjeka, N; Furin, J

2016-09-01

Multidrug-resistant tuberculosis (MDR-TB) is a serious public health problem, but the new drugs bedaquiline (BDQ) and delamanid offer hope to improve outcomes and minimise toxicity. In Khayelitsha, South Africa, patients are routinely started on BDQ in the out-patient setting. This report from the field describes BDQ use in the out-patient setting at the Nolungile Clinic. The clinic staff overall report a positive experience using the drug. Challenges have been based largely on the logistics of drug supply and delivery. BDQ can be started successfully in the out-patient setting, and can be a positive experience for both patients and providers. La tuberculose multirésistante (TB-MDR) est un problème de santé publique grave, mais les nouveaux médicaments que sont la bédaquiline (BDQ) et le délamanide apportent un espoir d'améliorer les résultats tout en réduisant la toxicité. A Khayelitsha, Afrique du Sud, les patients démarrent leur traitement par BDQ en consultation externe en routine. Ce rapport du terrain décrit l'utilisation de la BDQ à la consultation externe du dispensaire Nolungile. Dans l'ensemble, le personnel du centre de santé exprime une expérience positive du médicament. Les défis ont surtout été liés à la logistique de l'approvisionnement et de la distribution du médicament. La BDQ peut être mise en route avec succès dans le cadre d'une consultation externe et peut constituer une expérience positive pour les patients et les prestataires de soins. La tuberculosis multirresistente (TB-MDR) representa un grave problema de salud pública, pero la utilización de nuevos medicamentos como la bedaquilina (BDQ) y el delamanid ofrece perspectivas de mejores desenlaces terapéuticos y disminución de la toxicidad asociada. En Khayelitsha, Suráfrica, se inicia de manera sistemática el tratamiento ambulatorio con BDQ. En el presente informe del terreno, se describe la utilización de BDQ en tratamiento antituberculoso ambulatorio en el centro de atención Nolungile. En general, los miembros del personal del centro refirieron una experiencia positiva con la administración del medicamento. Las dificultades surgieron en gran parte con respecto a aspectos logísticos del suministro y la administración del medicamento. Es posible iniciar un tratamiento eficaz con BDQ en condiciones ambulatorias, y represente una experiencia positiva para los pacientes y los profesionales de salud.

Ambulatory Feedback System

NASA Technical Reports Server (NTRS)

Finger, Herbert; Weeks, Bill

1985-01-01

This presentation discusses instrumentation that will be used for a specific event, which we hope will carry on to future events within the Space Shuttle program. The experiment is the Autogenic Feedback Training Experiment (AFTE) scheduled for Spacelab 3, currently scheduled to be launched in November, 1984. The objectives of the AFTE are to determine the effectiveness of autogenic feedback in preventing or reducing space adaptation syndrome (SAS), to monitor and record in-flight data from the crew, to determine if prediction criteria for SAS can be established, and, finally, to develop an ambulatory instrument package to mount the crew throughout the mission. The purpose of the Ambulatory Feedback System (AFS) is to record the responses of the subject during a provocative event in space and provide a real-time feedback display to reinforce the training.

$$\\mathscr{H}_2$$ optimal control techniques for resistive wall mode feedback in tokamaks

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

Clement, Mitchell; Hanson, Jeremy; Bialek, Jim

DIII-D experiments show that a new, advanced algorithm improves resistive wall mode (RWM) stability control in high performance discharges using external coils. DIII-D can excite strong, locked or nearly locked external kink modes whose rotation frequencies and growth rates are on the order of the magnetic ux di usion time of the vacuum vessel wall. The VALEN RWM model has been used to gauge the e ectiveness of RWM control algorithms in tokamaks. Simulations and experiments have shown that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better, using 77% less current, than classical techniques when usingmore » control coils external to DIII-D's vacuum vessel. Experiments were conducted to develop control of a rotating n = 1 perturbation using an LQG controller derived from VALEN and external coils. Feedback using this LQG algorithm outperformed a proportional gain only controller in these perturbation experiments over a range of frequencies. Results from high N experiments also show that advanced feedback techniques using external control coils may be as e ective as internal control coil feedback using classical control techniques.« less

$$\\mathscr{H}_2$$ optimal control techniques for resistive wall mode feedback in tokamaks

DOE PAGES

Clement, Mitchell; Hanson, Jeremy; Bialek, Jim; ...

2018-02-28

DIII-D experiments show that a new, advanced algorithm improves resistive wall mode (RWM) stability control in high performance discharges using external coils. DIII-D can excite strong, locked or nearly locked external kink modes whose rotation frequencies and growth rates are on the order of the magnetic ux di usion time of the vacuum vessel wall. The VALEN RWM model has been used to gauge the e ectiveness of RWM control algorithms in tokamaks. Simulations and experiments have shown that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better, using 77% less current, than classical techniques when usingmore » control coils external to DIII-D's vacuum vessel. Experiments were conducted to develop control of a rotating n = 1 perturbation using an LQG controller derived from VALEN and external coils. Feedback using this LQG algorithm outperformed a proportional gain only controller in these perturbation experiments over a range of frequencies. Results from high N experiments also show that advanced feedback techniques using external control coils may be as e ective as internal control coil feedback using classical control techniques.« less

A ``Cyber Wind Facility'' for HPC Wind Turbine Field Experiments

NASA Astrophysics Data System (ADS)

Brasseur, James; Paterson, Eric; Schmitz, Sven; Campbell, Robert; Vijayakumar, Ganesh; Lavely, Adam; Jayaraman, Balaji; Nandi, Tarak; Jha, Pankaj; Dunbar, Alex; Motta-Mena, Javier; Craven, Brent; Haupt, Sue

2013-03-01

The Penn State ``Cyber Wind Facility'' (CWF) is a high-fidelity multi-scale high performance computing (HPC) environment in which ``cyber field experiments'' are designed and ``cyber data'' collected from wind turbines operating within the atmospheric boundary layer (ABL) environment. Conceptually the ``facility'' is akin to a high-tech wind tunnel with controlled physical environment, but unlike a wind tunnel it replicates commercial-scale wind turbines operating in the field and forced by true atmospheric turbulence with controlled stability state. The CWF is created from state-of-the-art high-accuracy technology geometry and grid design and numerical methods, and with high-resolution simulation strategies that blend unsteady RANS near the surface with high fidelity large-eddy simulation (LES) in separated boundary layer, blade and rotor wake regions, embedded within high-resolution LES of the ABL. CWF experiments complement physical field facility experiments that can capture wider ranges of meteorological events, but with minimal control over the environment and with very small numbers of sensors at low spatial resolution. I shall report on the first CWF experiments aimed at dynamical interactions between ABL turbulence and space-time wind turbine loadings. Supported by DOE and NSF.

Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

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

Pei, Yuanjiang; Som, Sibendu; Pomraning, Eric

2015-12-01

An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a detailed combustion model along with a dynamic structure LES model to evaluate its performance at engine-relevant conditions and understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a detailed combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of RANS predictions. The LES data suggests that the first ignition initiatesmore » in lean mixture and propagates to rich mixture, and the main ignition happens in rich mixture, preferable less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled and modulated by flame propagation. Soot predictions by LES present much better agreement with experiments compared to RANS both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 2 and 5 realizations can reach 99\\% of similarity to the target average of 16 realizations on the temperature and mixture fraction fields, respectively. However, more realizations are necessary for OH and soot mass fraction due to their high fluctuations.« less

FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

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

George Rizeq; Janice West; Arnaldo Frydman

Further development of a combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this sixth quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, in-situ adaptive tabulation (ISAT) for efficient chemical rate storage and retrieval was implemented and tested within the Linear Eddy Model (LEM). ISAT type 3 is being tested so that extrapolation can be performed and further improve the retrieval rate. Further testing of the LEM for subgrid chemistry was performed for parallel applicationsmore » and for multi-step chemistry. Validation of the software on backstep and bluff-body reacting cases were performed. Initial calculations of the SimVal experiment at Georgia Tech using their LES code were performed. Georgia Tech continues the effort to parameterize the LEM over composition space so that a neural net can be used efficiently in the combustion LES code. A new and improved Artificial Neural Network (ANN), with log-transformed output, for the 1-step chemistry was implemented in CFDRC's LES code and gave reasonable results. This quarter, the 2nd consortium meeting was held at CFDRC. Next quarter, LES software development and testing will continue. Alpha testing of the code will continue to be performed on cases of interest to the industrial consortium. Optimization of subgrid models will be pursued, particularly with the ISAT approach. Also next quarter, the demonstration of the neural net approach, for multi-step chemical kinetics speed-up in CFD-ACE+, will be accomplished.« less

Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

DOE PAGES

Pei, Yuanjiang; Som, Sibendu; Pomraning, Eric; ...

2015-10-14

An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a δ function combustion model along with a dynamic structure large eddy simulation (LES) model to evaluate its performance at engine-relevant conditions and to understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a δ function combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of Reynolds-averaged Navier—Stokes (RANS) predictions. Themore » LES data suggests that the first ignition initiates in a lean mixture and propagates to a rich mixture, and the main ignition happens in the rich mixture, preferably less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled. Soot predictions by LES present much better agreement with experiments compared to RANS, both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 5 and 6 realizations can reach 99% of similarity to the target average of 16 realizations on the mixture fraction and temperature fields, respectively. In conclusion, more realizations are necessary for the hydroxide (OH) and soot mass fractions due to their high fluctuations.« less

Specific interpretation of augmented feedback changes motor performance and cortical processing.

PubMed

Lauber, Benedikt; Keller, Martin; Leukel, Christian; Gollhofer, Albert; Taube, Wolfgang

2013-05-01

It is well established that the presence of external feedback, also termed augmented feedback, can be used to improve performance of a motor task. The present study aimed to elucidate whether differential interpretation of the external feedback signal influences the time to task failure of a sustained submaximal contraction and modulates motor cortical activity. In Experiment 1, subjects had to maintain a submaximal contraction (30% of maximum force) performed with their thumb and index finger. Half of the tested subjects were always provided with feedback about joint position (pF-group), whereas the other half of the subjects were always provided with feedback about force (fF-group). Subjects in the pF-group were led to belief in half of their trials that they would receive feedback about the applied force, and subjects in the fF-group to receive feedback about the position. In both groups (fF and pF), the time to task failure was increased when subjects thought to receive feedback about the force. In Experiment 2, subthreshold transcranial magnetic stimulation was applied over the right motor cortex and revealed an increased motor cortical activity when subjects thought to receive feedback about the joint position. The results showed that the interpretation of feedback influences motor behavior and alters motor cortical activity. The current results support previous studies suggesting a distinct neural control of force and position.

The effect of performance feedback on drivers' hazard perception ability and self-ratings.

PubMed

Horswill, Mark S; Garth, Megan; Hill, Andrew; Watson, Marcus O

2017-04-01

Drivers' hazard perception ability has been found to predict crash risk, and novice drivers appear to be particularly poor at this skill. This competency appears to develop only slowly with experience, and this could partially be a result of poor quality performance feedback. We report an experiment in which we provided high-quality artificial feedback on individual drivers' performance in a validated video-based hazard perception test via either: (1) a graph-based comparison of hazard perception response times between the test-taker, the average driver, and an expert driver; (2) a video-based comparison between the same groups; or (3) both. All three types of feedback resulted in both an improvement in hazard perception performance and a reduction in self-rated hazard perception skill, compared with a no-feedback control group. Video-based and graph-based feedback combined resulted in a greater improvement in hazard perception performance than either of the individual components, which did not differ from one another. All three types of feedback eliminated participants' self-enhancement bias for hazard perception skill. Participants judged both interventions involving video feedback to be significantly more likely to improve their real-world driving than the no feedback control group. While all three forms of feedback had some value, the combined video and graph feedback intervention appeared to be the most effective across all outcome measures. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of patient experience surveys in quality assurance and improvement: a focus group study in English general practice.

PubMed

Boiko, Olga; Campbell, John L; Elmore, Natasha; Davey, Antoinette F; Roland, Martin; Burt, Jenni

2015-12-01

Despite widespread adoption of patient feedback surveys in international health-care systems, including the English NHS, evidence of a demonstrable impact of surveys on service improvement is sparse. To explore the views of primary care practice staff regarding the utility of patient experience surveys. Qualitative focus groups. Staff from 14 English general practices. Whilst participants engaged with feedback from patient experience surveys, they routinely questioned its validity and reliability. Participants identified surveys as having a number of useful functions: for patients, as a potentially therapeutic way of getting their voice heard; for practice staff, as a way of identifying areas of improvement; and for GPs, as a source of evidence for professional development and appraisal. Areas of potential change stimulated by survey feedback included redesigning front-line services, managing patient expectations and managing the performance of GPs. Despite this, practice staff struggled to identify and action changes based on survey feedback alone. Whilst surveys may be used to endorse existing high-quality service delivery, their use in informing changes in service delivery is more challenging for practice staff. Drawing on the Utility Index framework, we identified concerns relating to reliability and validity, cost and feasibility acceptability and educational impact, which combine to limit the utility of patient survey feedback. Feedback from patient experience surveys has great potential. However, without a specific and renewed focus on how to translate feedback into action, this potential will remain incompletely realized. © 2014 The Authors Health Expectations Published by John Wiley & Sons Ltd.

Partial Compensation for Altered Auditory Feedback: A Tradeoff with Somatosensory Feedback?

ERIC Educational Resources Information Center

Katseff, Shira; Houde, John; Johnson, Keith

2012-01-01

Talkers are known to compensate only partially for experimentally-induced changes to their auditory feedback. In a typical experiment, talkers might hear their F1 feedback shifted higher (so that /[epsilon]/ sounds like /[ash]/, for example), and compensate by lowering F1 in their subsequent speech by about a quarter of that distance. Here, we…

Robotics and neuroscience: a rhythmic interaction.

PubMed

Ronsse, Renaud; Lefèvre, Philippe; Sepulchre, Rodolphe

2008-05-01

At the crossing between motor control neuroscience and robotics system theory, the paper presents a rhythmic experiment that is amenable both to handy laboratory implementation and simple mathematical modeling. The experiment is based on an impact juggling task, requiring the coordination of two upper-limb effectors and some phase-locking with the trajectories of one or several juggled objects. We describe the experiment, its implementation and the mathematical model used for the analysis. Our underlying research focuses on the role of sensory feedback in rhythmic tasks. In a robotic implementation of our experiment, we study the minimum feedback that is required to achieve robust control. A limited source of feedback, measuring only the impact times, is shown to give promising results. A second field of investigation concerns the human behavior in the same impact juggling task. We study how a variation of the tempo induces a transition between two distinct control strategies with different sensory feedback requirements. Analogies and differences between the robotic and human behaviors are obviously of high relevance in such a flexible setup.

Croissance epitaxiale de GaAs sur substrats de Ge par epitaxie par faisceaux chimiques

NASA Astrophysics Data System (ADS)

Belanger, Simon

La situation energetique et les enjeux environnementaux auxquels la societe est confrontee entrainent un interet grandissant pour la production d'electricite a partir de l'energie solaire. Parmi les technologies actuellement disponibles, la filiere du photovoltaique a concentrateur solaire (CPV pour concentrator photovoltaics) possede un rendement superieur et mi potentiel interessant a condition que ses couts de production soient competitifs. La methode d'epitaxie par faisceaux chimiques (CBE pour chemical beam epitaxy) possede plusieurs caracteristiques qui la rendent interessante pour la production a grande echelle de cellules photovoltaiques a jonctions multiples a base de semi-conducteurs III-V. Ce type de cellule possede la meilleure efficacite atteinte a ce jour et est utilise sur les satellites et les systemes photovoltaiques a concentrateur solaire (CPV) les plus efficaces. Une des principales forces de la technique CBE se trouve dans son potentiel d'efficacite d'utilisation des materiaux source qui est superieur a celui de la technique d'epitaxie qui est couramment utilisee pour la production a grande echelle de ces cellules. Ce memoire de maitrise presente les travaux effectues dans le but d'evaluer le potentiel de la technique CBE pour realiser la croissance de couches de GaAs sur des substrats de Ge. Cette croissance constitue la premiere etape de fabrication de nombreux modeles de cellules solaires a haute performance decrites plus haut. La realisation de ce projet a necessite le developpement d'un procede de preparation de surface pour les substrats de germanium, la realisation de nombreuses sceances de croissance epitaxiale et la caracterisation des materiaux obtenus par microscopie optique, microscopie a force atomique (AFM), diffraction des rayons-X a haute resolution (HRXRD), microscopie electronique a transmission (TEM), photoluminescence a basse temperature (LTPL) et spectrometrie de masse des ions secondaires (SIMS). Les experiences ont permis de confirmer l'efficacite du procede de preparation de surface et d'identifier les conditions de croissance optimales. Les resultats de caracterisation indiquent que les materiaux obtenus presentent une tres faible rugosite de surface, une bonne qualite cristalline et un dopage residuel relativement important. De plus, l'interface GaAs/Ge possede une faible densite de defauts. Finalement, la diffusion d'arsenic dans le substrat de germanium est comparable aux valeurs trouvees dans la litterature pour la croissance a basse temperature avec les autres procedes d'epitaxie courants. Ces resultats confirment que la technique d'epitaxie par faisceaux chimiques (CBE) permet de produire des couches de GaAs sur Ge de qualite adequate pour la fabrication de cellules solaires a haute performance. L'apport a la communaute scientifique a ete maximise par le biais de la redaction d'un article soumis a la revue Journal of Crystal Growth et la presentation des travaux a la conference Photovoltaics Canada 2010 . Mots-cles : Epitaxie par jets chimiques, Chemical beam epitaxy, CBE, MOMBE, Germanium, GaAs, Ge

The influence of misrepresenting the nocturnal boundary layer on idealized daytime convection in large-eddy simulation

NASA Astrophysics Data System (ADS)

van Stratum, Bart J. H.; Stevens, Bjorn

2015-06-01

The influence of poorly resolving mixing processes in the nocturnal boundary layer (NBL) on the development of the convective boundary layer the following day is studied using large-eddy simulation (LES). Guided by measurement data from meteorological sites in Cabauw (Netherlands) and Hamburg (Germany), the typical summertime NBL conditions for Western Europe are characterized, and used to design idealized (absence of moisture and large-scale forcings) numerical experiments of the diel cycle. Using the UCLA-LES code with a traditional Smagorinsky-Lilly subgrid model and a simplified land-surface scheme, a sensitivity study to grid spacing is performed. At horizontal grid spacings ranging from 3.125 m in which we are capable of resolving most turbulence in the cases of interest to grid a spacing of 100 m which is clearly insufficient to resolve the NBL, the ability of LES to represent the NBL and the influence of NBL biases on the subsequent daytime development of the convective boundary layer are examined. Although the low-resolution experiments produce substantial biases in the NBL, the influence on daytime convection is shown to be small, with biases in the afternoon boundary layer depth and temperature of approximately 100 m and 0.5 K, which partially cancel each other in terms of the mixed-layer top relative humidity.

Pompage optique et violation de parité dans l'atome

NASA Astrophysics Data System (ADS)

Bouchiat, M.-A.

Between the original Kastler work about polarization of the Hg vapour fluorescence (1936) and the parity violation experiment in Cesium [5], we notice a relationship in the methods of investigation and in the nature of the physical problems under consideration : an illustration of the richness of the research field pioneered by Alfred Kastler. This paper adopts a phenomenological description of the Cesium parity violation experiment, without reference to electroweak theory. This allows to shed light on the peculiar features of our experiment which seem to contradict the optical pumping lore. When the 6S-7S forbidden transition in Cesium is excited, the electronic spin orientation of the 7S state exhibits two anomalies : the first one can be associated with a breakdown of a rotational invariance of the atom-radiation field system by the external dc electric field, the second one, much more fundamental, is a right-left asymmetry, Le. a manifestation of a parity violation not accounted for by conventional QED. The interpretation of this new optical pumping effect involves the introduction of three different dipole moments : the strongly suppressed magnetic dipole, an electric dipole induced by the Stark field and one directed along the spin momentum indicating the presence of the parity violating, but Tconserving, electron-nucleus interaction. When the transition is excited, the radiation field is absorbed coherently by these transition dipoles. The breakdown of the usual optical pumping rules can be explained in terms of interference between the amplitudes associated with two different dipoles. In particular, the interference of the Stark dipole with the PV dipole leads to a component of the 7S spin orientation which behaves under mirror symmetry as a polar vector, and not as an axial vector as one would normally expect for an angular momentum type quantity. Basically, the experiment consists in studying the effects upon the properties of the fluorescence light, polarized and unpolarized, produced by mirror symmetries with respect to three orthogonal planes. In this way, it is possible to disentangle the different interference terms and to discriminate the one involving parity violation. In practice, this is done by reversing various parameters of the experiment. The control of the quality of these reversals is obviously the crucial part of the whole experimental procedure. Moreover consistency tests and various cross-checks have to be devised and carefully carried out. They contribute to reliability of the result. In the Cesium experiment, the uncertainty associated with possible systematic effects is estimated to 8 % and the eqm statistical uncertainty, after combination of two independent measurements which satisfactorily crosscheck one another, is 11%. The parity violation can be readily interpreted in terms of the short range electronnucleon interaction associated with the exchange of the neutral vector boson Z0 recently observed with the CERN p-p collider. This new type of interaction, also known under the generic name of « neutral currents » was one of the most important predictions of electroweak theory which unifies, within the frame of gauge field theories, electromagnetic and weak interactions. This experiment, originally designed as a test of electroweak theory, gives information on the structure of neutral currents which complement those obtained by high energy experiments. First, the explored energy range is obviously very different. Secondly, the quarks acting coherently in Atomic Physics experiment but incoherently in accelerator experiments, the basic electroweak parameters extracted from the two kinds of experiments are different. Entre les travaux initiaux de Kastler sur la polarisation de la lumière de fluorescence émise par une vapeur de mercure (1936) et la violation de la parité dans le césium (1982), il existe un lien de parenté dans les méthodes d'investigation et dans la nature des problèmes physiques abordés. Ceci illustre la richesse du champ de recherche ouvert sous l'impulsion de Kastler. La présentation adoptée ici fait le choix d'une description phénoménologique de l'expérience violation de parité dans le césium, indépendamment de toute référence à la théorie électrofaible. Ceci met en lumière les caractères remarquables du résultat qui semblent contredire tout le savoir du pompage optique. Lorsque la transition interdite 6S-7S du césium est excitée, l'orientation du spin électronique dans l'état 7S manifeste certaines anomalies. L'une est de caractère fondamental : il s'agit d'une asymétrie droite-gauche, manifestant une violation de la parité dont ne peut rendre compte la théorie EDQ. L'interprétation met en jeu plusieurs moments dipolaires de transition dont deux dipôles électriques, l'un induit par effet Stark et l'autre dirigé le long du moment angulaire de spin indiquant la présence d'une interaction électron-nucléon violant la parité. L'interférence des amplitudes de transition associée à ces deux dipôles produit une composante de l'orientation du spin dans l'état 7S se comportant de manière anormale : deux expériences images miroir l'une de l'autre conduisent pour cette composante à des résultats qui ne sont pas images miroir l'un de l'autre. Dans son principe, l'expérience consiste à étudier sur les propriétés de la lumière de fluorescence polarisée les effets produits par les réflexions miroirs réalisées par rapport à trois plans orthogonaux. Le contrôle de l'exactitude avec laquelle sont réalisées ces réflexions constitue la part cruciale de toute la procédure expérimentale. Dans notre expérience, aucune correction significative ne s'avère nécessaire. L'incertitude associée aux effets systématiques possibles est estimée à 8 %. En combinant les résultats de deux mesures indépendantes qui se recoupent de manière satisfaisante, l'incertitude statistique est 11 % (1 eqm). La violation de la parité peut être directement interprétée à l'aide de l'interaction électron-nucléon à très courte portée associée à l'échange du boson vectoriel neutre Z 0, dite interaction « à courants neutres ». L'existence de ce type nouveau d'interaction constitue l'une des prédictions les plus importantes de la théorie électrofaible unifiant les interactions électromagnétiques et faibles. L'expérience du césium, initialement conçue comme test de la théorie électrofaible, donne sur la structure des courants neutres des informations qui s'avèrent complémentaires de celles obtenues par les expériences de hautes énergies.

Doctors' engagements with patient experience surveys in primary and secondary care: a qualitative study.

PubMed

Farrington, Conor; Burt, Jenni; Boiko, Olga; Campbell, John; Roland, Martin

2017-06-01

Patient experience surveys are increasingly important in the measurement of, and attempts to improve, health-care quality. To date, little research has focused upon doctors' attitudes to surveys which give them personalized feedback. This paper explores doctors' perceptions of patient experience surveys in primary and secondary care settings in order to deepen understandings of how doctors view the plausibility of such surveys. We conducted a qualitative study with doctors in two regions of England, involving in-depth semi-structured interviews with doctors working in primary care (n = 21) and secondary care (n = 20) settings. The doctors in both settings had recently received individualized feedback from patient experience surveys. Doctors in both settings express strong personal commitments to incorporating patient feedback in quality improvement efforts. However, they also concurrently express strong negative views about the credibility of survey findings and patients' motivations and competence in providing feedback. Thus, individual doctors demonstrate contradictory views regarding the plausibility of patient surveys, leading to complex, varied and on balance negative engagements with patient feedback. Doctors' contradictory views towards patient experience surveys are likely to limit the impact of such surveys in quality improvement initiatives in primary and secondary care. We highlight the need for 'sensegiving' initiatives (i.e. attempts to influence perceptions by communicating particular ideas, narratives and visions) to engage with doctors regarding the plausibility of patient experience surveys. This study highlights the importance of engaging with doctors' views about patient experience surveys when developing quality improvement initiatives. © 2016 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

Real-Time Performance Feedback for the Manual Control of Spacecraft

NASA Astrophysics Data System (ADS)

Karasinski, John Austin

Real-time performance metrics were developed to quantify workload, situational awareness, and manual task performance for use as visual feedback to pilots of aerospace vehicles. Results from prior lunar lander experiments with variable levels of automation were replicated and extended to provide insights for the development of real-time metrics. Increased levels of automation resulted in increased flight performance, lower workload, and increased situational awareness. Automated Speech Recognition (ASR) was employed to detect verbal callouts as a limited measure of subjects' situational awareness. A one-dimensional manual tracking task and simple instructor-model visual feedback scheme was developed. This feedback was indicated to the operator by changing the color of a guidance element on the primary flight display, similar to how a flight instructor points out elements of a display to a student pilot. Experiments showed that for this low-complexity task, visual feedback did not change subject performance, but did increase the subjects' measured workload. Insights gained from these experiments were applied to a Simplified Aid for EVA Rescue (SAFER) inspection task. The effects of variations of an instructor-model performance-feedback strategy on human performance in a novel SAFER inspection task were investigated. Real-time feedback was found to have a statistically significant effect of improving subject performance and decreasing workload in this complicated four degree of freedom manual control task with two secondary tasks.

General practitioner registrars' experiences of multisource feedback: a qualitative study.

PubMed

Findlay, Nigel

2012-09-01

To explore the experiences of general practitioner (GP) specialty training registrars, thereby generating more understanding of the ways in which multisource feedback impacts upon their self-perceptions and professional behaviour, and provide information that might guide its use in the revalidation process of practising GPs. Complete transcripts of semi-structured, audio-taped qualitative interviews were analysed using the constant comparative method, to describe the experiences of multisource feedback for individual registrars. Five GP registrars participated. The first theme to emerge was the importance of the educational supervisor in encouraging the registrar through the emotional response, then facilitating interpretation of feedback and personal development. The second was the differing attitudes to learning and development, which may be in conflict with threats to self-image. The current RCGP format for obtaining multisource feedback for GP registrars may not always be achieving its purpose of challenging self-perceptions and motivating improved performance. An enhanced qualitative approach, through personal interviews rather than anonymous questionnaires, may provide a more accurate picture. This would address the concerns of some registrars by reducing their logistical burden and may facilitate more constructive feedback. The educational supervisor has an important role in promoting personal development, once this feedback is shared. The challenge for teaching organisations is to create a climate of comfort for learning, yet encourage learning beyond a 'comfort zone'.

Stochastic parameterization of shallow cumulus convection estimated from high-resolution model data

NASA Astrophysics Data System (ADS)

Dorrestijn, Jesse; Crommelin, Daan T.; Siebesma, A. Pier.; Jonker, Harm J. J.

2013-02-01

In this paper, we report on the development of a methodology for stochastic parameterization of convective transport by shallow cumulus convection in weather and climate models. We construct a parameterization based on Large-Eddy Simulation (LES) data. These simulations resolve the turbulent fluxes of heat and moisture and are based on a typical case of non-precipitating shallow cumulus convection above sea in the trade-wind region. Using clustering, we determine a finite number of turbulent flux pairs for heat and moisture that are representative for the pairs of flux profiles observed in these simulations. In the stochastic parameterization scheme proposed here, the convection scheme jumps randomly between these pre-computed pairs of turbulent flux profiles. The transition probabilities are estimated from the LES data, and they are conditioned on the resolved-scale state in the model column. Hence, the stochastic parameterization is formulated as a data-inferred conditional Markov chain (CMC), where each state of the Markov chain corresponds to a pair of turbulent heat and moisture fluxes. The CMC parameterization is designed to emulate, in a statistical sense, the convective behaviour observed in the LES data. The CMC is tested in single-column model (SCM) experiments. The SCM is able to reproduce the ensemble spread of the temperature and humidity that was observed in the LES data. Furthermore, there is a good similarity between time series of the fractions of the discretized fluxes produced by SCM and observed in LES.

Feedback in Clinical Education, Part I: Characteristics of Feedback Provided by Approved Clinical Instructors

PubMed Central

Nottingham, Sara; Henning, Jolene

2014-01-01

Context Providing students with feedback is an important component of athletic training clinical education; however, little information is known about the feedback that Approved Clinical Instructors (ACIs; now known as preceptors) currently provide to athletic training students (ATSs). Objective To characterize the feedback provided by ACIs to ATSs during clinical education experiences. Design Qualitative study. Setting One National Collegiate Athletic Association Division I athletic training facility and 1 outpatient rehabilitation clinic that were clinical sites for 1 entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. Patients or Other Participants A total of 4 ACIs with various experience levels and 4 second-year ATSs. Data Collection and Analysis Extensive field observations were audio recorded, transcribed, and integrated with field notes for analysis. The constant comparative approach of open, axial, and selective coding was used to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. Results The ACIs gave 88 feedback statements in 45 hours and 10 minutes of observation. Characteristics of feedback categories included purpose, timing, specificity, content, form, and privacy. Conclusions Feedback that ACIs provided included several components that made each feedback exchange unique. The ACIs in our study provided feedback that is supported by the literature, suggesting that ACIs are using current recommendations for providing feedback. Feedback needs to be investigated across multiple athletic training education programs to gain more understanding of certain areas of feedback, including frequency, privacy, and form. PMID:24143902

Large-eddy simulation/Reynolds-averaged Navier-Stokes hybrid schemes for high speed flows

NASA Astrophysics Data System (ADS)

Xiao, Xudong

Three LES/RANS hybrid schemes have been proposed for the prediction of high speed separated flows. Each method couples the k-zeta (Enstrophy) BANS model with an LES subgrid scale one-equation model by using a blending function that is coordinate system independent. Two of these functions are based on turbulence dissipation length scale and grid size, while the third one has no explicit dependence on the grid. To implement the LES/RANS hybrid schemes, a new rescaling-reintroducing method is used to generate time-dependent turbulent inflow conditions. The hybrid schemes have been tested on a Mach 2.88 flow over 25 degree compression-expansion ramp and a Mach 2.79 flow over 20 degree compression ramp. A special computation procedure has been designed to prevent the separation zone from expanding upstream to the recycle-plane. The code is parallelized using Message Passing Interface (MPI) and is optimized for running on IBM-SP3 parallel machine. The scheme was validated first for a flat plate. It was shown that the blending function has to be monotonic to prevent the RANS region from appearing in the LES region. In the 25 deg ramp case, the hybrid schemes provided better agreement with experiment in the recovery region. Grid refinement studies demonstrated the importance of using a grid independent blend function and further improvement with experiment in the recovery region. In the 20 deg ramp case, with a relatively finer grid, the hybrid scheme characterized by grid independent blending function well predicted the flow field in both the separation region and the recovery region. Therefore, with "appropriately" fine grid, current hybrid schemes are promising for the simulation of shock wave/boundary layer interaction problems.

Determination of the dissolution slowness surface by study of etched shapes I. Morphology of the dissolution slowness surface and theoretical etched shapes

NASA Astrophysics Data System (ADS)

Leblois, T.; Tellier, C. R.

1992-07-01

We propose a theoretical model for the anisotropic etching of crystals, in order to be applied in the micromachining. The originality of the model is due to the introduction of dissolution tensors to express the representative surface of the dissolution slowness. The knowledge of the equation of the slowness surface allows us to determine the trajectories of all the elements which compose the starting surface. It is then possible to construct the final etched shape by numerical simulation. Several examples are given in this paper which show that the final etched shapes are correlated to the extrema of the dissolution slowness. Since the slowness surface must be determined from experiments, emphasis is placed on difficulties encountered when we correlate theory to experiments. Nous avons modélisé le processus de dissolution anisotrope des cristaux en vue d'une application à la simulation des formes obtenues par photolithogravure chimique. La principale originalité de ce modèle tient à l'introduction de tenseurs de dissolution pour exprimer la surface représentative de la lenteur de dissolution. La connaissance de l'équation de la lenteur de dissolution permet de calculer les trajectoires des différents éléments constituant la surface de départ puis de reconstituer par simulation la forme dissoute. Les simulations démontrent que les formes limites des cristaux dissous sont corrélées aux extrema de la lenteur de dissolution. La détermination de la surface de la lenteur se faisant à partir de mesures expérimetales, nous nous sommes efforcés de montrer toutes les difficultés attachées à cette analyse.

Variable force and visual feedback effects on teleoperator man/machine performance

NASA Technical Reports Server (NTRS)

Massimino, Michael J.; Sheridan, Thomas B.

1989-01-01

An experimental study was conducted to determine the effects of various forms of visual and force feedback on human performance for several telemanipulation tasks. Experiments were conducted with varying frame rates and subtended visual angles, with and without force feedback.

Feedback Practices and Signature Pedagogies: What Can the Liberal Arts Learn from the Design Critique?

ERIC Educational Resources Information Center

Schrand, Tom; Eliason, John

2012-01-01

To examine the differences between feedback practices in liberal arts courses and in design courses, we surveyed 373 students with experiences of both. Our study found that students perceived the feedback they received in design courses as more effective in advancing their learning, and that the emotional effects of feedback presented verbally and…

Mitigation of Cognitive Bias with a Serious Game: Two Experiments Testing Feedback Timing and Source

ERIC Educational Resources Information Center

Dunbar, Norah E.; Jensen, Matthew L.; Miller, Claude H.; Bessarabova, Elena; Lee, Yu-Hao; Wilson, Scott N.; Elizondo, Javier; Adame, Bradley J.; Valacich, Joseph; Straub, Sara; Burgoon, Judee K.; Lane, Brianna; Piercy, Cameron W.; Wilson, David; King, Shawn; Vincent, Cindy; Schuetzler, Ryan M.

2017-01-01

One of the benefits of using digital games for education is that games can provide feedback for learners to assess their situation and correct their mistakes. We conducted two studies to examine the effectiveness of different feedback design (timing, duration, repeats, and feedback source) in a serious game designed to teach learners about…

The Value and Effectiveness of Feedback in Improving Students' Learning and Professionalizing Teaching in Higher Education

ERIC Educational Resources Information Center

Ahea, Md. Mamoon-Al-Bashir; Ahea, Md. Rezaul Kabir; Rahman, Ismat

2016-01-01

There is a great importance of feedback in improving learning experience for the students. This has also significant effect in professionalizing teaching in the higher education level. However, feedback is considered as a difficult issue in this arena. Most of the lecturers are still continuing with the tradition form of feedback. This form of…

Advanced feedback control methods in EXTRAP T2R reversed field pinch

NASA Astrophysics Data System (ADS)

Yadikin, D.; Brunsell, P. R.; Paccagnella, R.

2006-07-01

Previous experiments in the EXTRAP T2R reversed field pinch device have shown the possibility of suppression of multiple resistive wall modes (RWM). A feedback system has been installed in EXTRAP T2R having 100% coverage of the toroidal surface by the active coil array. Predictions based on theory and the previous experimental results show that the number of active coils should be sufficient for independent stabilization of all unstable RWMs in the EXTRAP T2R. Experiments using different feedback schemes are performed, comparing the intelligent shell, the fake rotating shell, and the mode control with complex feedback gains. Stabilization of all unstable RWMs throughout the discharge duration of td≈10τw is seen using the intelligent shell feedback scheme. Mode rotation and the control of selected Fourier harmonics is obtained simultaneously using the mode control scheme with complex gains. Different sensor signals are studied. A feedback system with toroidal magnetic field sensors could have an advantage of lower feedback gain needed for the RWM suppression compared to the system with radial magnetic field sensors. In this study, RWM suppression is demonstrated, using also the toroidal field component as a sensor signal in the feedback system.

Age vs. experience : evaluation of a video feedback intervention for newly licensed teen drivers.

DOT National Transportation Integrated Search

2013-02-06

This project examines the effects of age, experience, and video-based feedback on the rate and type of safety-relevant events captured on video event : recorders in the vehicles of three groups of newly licensed young drivers: : 1. 14.5- to 15.5-year...

E-Pad: a comfortable electrocutaneous-based tactile feedback display

NASA Astrophysics Data System (ADS)

Wang, Jiabin; Zhao, Lu; Liu, Yue; Wang, Yongtian; Cai, Yi

2018-01-01

The devices with touchscreen are becoming more popular recently; however, most of them suffer from the crucial drawbacks of lacking accurate tactile feedback. A novel electrocutaneous-based tactile device with the name of E-pad is proposed to provide a dynamic and static low-voltage feedback for touchscreen. We optimize the key parameters of the output voltage and design custom-made hardwares to guarantee a comfortable user experience. Users could move their fingers freely across the touchscreen of the proposed device to really feel virtual objects. Two preliminary experiments are conducted to evaluate the interactive performance of the proposed device and the experimental results show that the proposed device can provide a comfortable and distinct tactile feedback.

Enhancing the Performance of Passive Teleoperation Systems via Cutaneous Feedback.

PubMed

Pacchierotti, Claudio; Tirmizi, Asad; Bianchini, Gianni; Prattichizzo, Domenico

2015-01-01

We introduce a novel method to improve the performance of passive teleoperation systems with force reflection. It consists of integrating kinesthetic haptic feedback provided by common grounded haptic interfaces with cutaneous haptic feedback. The proposed approach can be used on top of any time-domain control technique that ensures a stable interaction by scaling down kinesthetic feedback when this is required to satisfy stability conditions (e.g., passivity) at the expense of transparency. Performance is recovered by providing a suitable amount of cutaneous force through custom wearable cutaneous devices. The viability of the proposed approach is demonstrated through an experiment of perceived stiffness and an experiment of teleoperated needle insertion in soft tissue.

Reduced sensitivity to neutral feedback versus negative feedback in subjects with mild depression: Evidence from event-related potentials study.

PubMed

Li, Peng; Song, Xinxin; Wang, Jing; Zhou, Xiaoran; Li, Jiayi; Lin, Fengtong; Hu, Zhonghua; Zhang, Xinxin; Cui, Hewei; Wang, Wenmiao; Li, Hong; Cong, Fengyu; Roberson, Debi

2015-11-01

Many previous event-related potential (ERP) studies have linked the feedback related negativity (FRN) component with medial frontal cortex processing and associated this component with depression. Few if any studies have investigated the processing of neutral feedback in mildly depressive subjects in the normal population. Two experiments compared brain responses to neutral feedback with behavioral performance in mildly depressed subjects who scored highly on the Beck Depression Inventory (high BDI) and a control group with lower BDI scores (low BDI). In the first study, the FRN component was recorded when neutral, negative or positive feedback was pseudo-randomly delivered to the two groups in a time estimation task. In the second study, real feedback was provided to the two groups in the same task in order to measure their actual accuracy of performance. The results of experiment one (Exp. 1) revealed that a larger FRN effect was elicited by neutral feedback than by negative feedback in the low BDI group, but no significant difference was found between neutral condition and negative condition in the High BDI group. The present findings demonstrated that depressive tendencies influence the processing of neutral feedback in medial frontal cortex. The FRN effect may work as a helpful index for investigating cognitive bias in depression in future studies. Copyright © 2015 Elsevier Inc. All rights reserved.

Dynamic Mesoscale Land-Atmosphere Feedbacks in Fragmented Forests in Amazonia

NASA Astrophysics Data System (ADS)

Rastogi, D.; Baidya Roy, S.

2011-12-01

This paper investigates land-atmosphere feedbacks in disturbed rainforests of Amazonia. Deforestation along the rapidly expanding highways and road network has created the unique fishbone land cover pattern in Rondonia, a state in southwestern Amazonia. Numerical experiments and observations show that sharp gradients in land cover due to the fishbone heterogeneity triggers mesoscale circulations. These circulations significantly change the spatial pattern of local hydrometeorology, especially convection, clouds and precipitation. The primary research question now is can these changes in local hydrometeorology affect vegetation growth in the clearings. If so, that would be a clear indication that land-atmosphere feedbacks can affect vegetation recovery in fragmented forests. A computationally-efficient modeling tool consisting of a mesoscale atmospheric model dynamically coupled with a plant growth model has been specifically developed to identify the atmospheric feedback pathways. Preliminary experiments focus on the seasonal-scale feedbacks during the dry season. Results show that temperature, incoming shortwave and precipitation are the three primary drivers through which the feedbacks operate. Increasing temperature increases respiratory losses generating a positive feedback. Increased cloud cover reduces incoming PAR and photosynthesis, resulting in a positive feedback. Increased precipitation reduces water stress and promotes growth resulting in a negative feedback. The net effect is a combination of these 3 feedback loops. These findings can significantly improve our understanding of ecosystem resiliency in disturbed tropical forests.

Ultra-Parameterized CAM: Progress Towards Low-Cloud Permitting Superparameterization

NASA Astrophysics Data System (ADS)

Parishani, H.; Pritchard, M. S.; Bretherton, C. S.; Khairoutdinov, M.; Wyant, M. C.; Singh, B.

2016-12-01

A leading source of uncertainty in climate feedback arises from the representation of low clouds, which are not resolved but depend on small-scale physical processes (e.g. entrainment, boundary layer turbulence) that are heavily parameterized. We show results from recent attempts to achieve an explicit representation of low clouds by pushing the computational limits of cloud superparameterization to resolve boundary-layer eddy scales relevant to marine stratocumulus (250m horizontal and 20m vertical length scales). This extreme configuration is called "ultraparameterization". Effects of varying horizontal vs. vertical resolution are analyzed in the context of altered constraints on the turbulent kinetic energy statistics of the marine boundary layer. We show that 250m embedded horizontal resolution leads to a more realistic boundary layer vertical structure, but also to an unrealistic cloud pulsation that cannibalizes time mean LWP. We explore the hypothesis that feedbacks involving horizontal advection (not typically encountered in offline LES that neglect this degree of freedom) may conspire to produce such effects and present strategies to compensate. The results are relevant to understanding the emergent behavior of quasi-resolved low cloud decks in a multi-scale modeling framework within a previously unencountered grey zone of better resolved boundary-layer turbulence.

Configurable, wearable sensing and vibrotactile feedback system for real-time postural balance and gait training: proof-of-concept.

PubMed

Xu, Junkai; Bao, Tian; Lee, Ung Hee; Kinnaird, Catherine; Carender, Wendy; Huang, Yangjian; Sienko, Kathleen H; Shull, Peter B

2017-10-11

Postural balance and gait training is important for treating persons with functional impairments, however current systems are generally not portable and are unable to train different types of movements. This paper describes a proof-of-concept design of a configurable, wearable sensing and feedback system for real-time postural balance and gait training targeted for home-based treatments and other portable usage. Sensing and vibrotactile feedback are performed via eight distributed, wireless nodes or "Dots" (size: 22.5 × 20.5 × 15.0 mm, weight: 12.0 g) that can each be configured for sensing and/or feedback according to movement training requirements. In the first experiment, four healthy older adults were trained to reduce medial-lateral (M/L) trunk tilt while performing balance exercises. When trunk tilt deviated too far from vertical (estimated via a sensing Dot on the lower spine), vibrotactile feedback (via feedback Dots placed on the left and right sides of the lower torso) cued participants to move away from the vibration and back toward the vertical no feedback zone to correct their posture. A second experiment was conducted with the same wearable system to train six healthy older adults to alter their foot progression angle in real-time by internally or externally rotating their feet while walking. Foot progression angle was estimated via a sensing Dot adhered to the dorsal side of the foot, and vibrotactile feedback was provided via feedback Dots placed on the medial and lateral sides of the mid-shank cued participants to internally or externally rotate their foot away from vibration. In the first experiment, the wearable system enabled participants to significantly reduce trunk tilt and increase the amount of time inside the no feedback zone. In the second experiment, all participants were able to adopt new gait patterns of internal and external foot rotation within two minutes of real-time training with the wearable system. These results suggest that the configurable, wearable sensing and feedback system is portable and effective for different types of real-time human movement training and thus may be suitable for home-based or clinic-based rehabilitation applications.

New Supervisors' Struggles and Successes with Corrective Feedback

ERIC Educational Resources Information Center

Borders, L. DiAnne; Welfare, Laura E.; Sackett, Corrine R.; Cashwell, Craig

2017-01-01

Seven doctoral supervisors described their experiences giving corrective feedback, including events when constructive feedback and confrontation did and did not go well. Findings reveal their thoughts and feelings before, during, and after each event. The authors suggest several specific pedagogical directions for facilitating supervisor…

[Consequences of an institutionalized childhood: the case of the "Duplessis orphans"].

PubMed

Boucher, Sophie; Paré, Nikolas; Perry, J Christopher; Sigal, John J; Ouimet, Marie-Claude

2008-01-01

Whereas the immediate consequences of institutionalized placements on children have been documented, no study has investigated adults who were raised in orphanages or institutions. In Quebec, les enfants de Duplessis offer a unique testimony of the long term consequences of an institutionalized childhood. Stories collected from 40 men and 41 women who grew up in institution in Duplessis'era indicate a high number of abuse and aversive experiences, including physical, psychological and sexual aggressions. In addition, the environment was poor in stimulation and opportunities to develop positive attachment relationships with adults. When matched and compared to adults from the Santé-Québec survey, les enfants de Duplessis report a higher number of health problems associated with stress and more psychological distress. Moreover, our results indicate that those who had fewer strengths and aptitudes in childhood are the most affected by unfavourable experiences.

Investigation of transient ignition process in a cavity based scramjet combustor using combined ethylene injectors

NASA Astrophysics Data System (ADS)

Liu, Xiao; Cai, Zun; Tong, Yiheng; Zheng, Hongtao

2017-08-01

Large Eddy Simulation (LES) and experiment were employed to investigate the transient ignition and flame propagation process in a rearwall-expansion cavity scramjet combustor using combined fuel injection schemes. The compressible supersonic solver and three ethylene combustion mechanisms were first validated against experimental data and results show in reasonably good agreement. Fuel injection scheme combining transverse and direct injectors in the cavity provides a benefit mixture distribution and could achieve a successful ignition. Four stages are illustrated in detail from both experiment and LES. After forced ignition in the cavity, initial flame kernel propagates upstream towards the cavity front edge and ignites the mixture, which acts as a continuous pilot flame, and then propagates downstream along the cavity shear layer rapidly to the combustor exit. Cavity shear layer flame stabilization mode can be concluded from the heat release rate and local high temperature distribution during the combustion process.

The hybrid RANS/LES of partially premixed supersonic combustion using G/Z flamelet model

NASA Astrophysics Data System (ADS)

Wu, Jinshui; Wang, Zhenguo; Bai, Xuesong; Sun, Mingbo; Wang, Hongbo

2016-10-01

In order to describe partially premixed supersonic combustion numerically, G/Z flamelet model is developed and compared with finite rate model in hybrid RANS/LES simulation to study the strut-injection supersonic combustion flow field designed by the German Aerospace Center. A new temperature calculation method based on time-splitting method of total energy is introduced in G/Z flamelet model. Simulation results show that temperature predictions in partially premixed zone by G/Z flamelet model are more consistent with experiment than finite rate model. It is worth mentioning that low temperature reaction zone behind the strut is well reproduced. Other quantities such as average velocity and average velocity fluctuation obtained by developed G/Z flamelet model are also in good agreement with experiment. Besides, simulation results by G/Z flamelet also reveal the mechanism of partially premixed supersonic combustion by the analyses of the interaction between turbulent burning velocity and flow field.

On the Adaptation of Pelvic Motion by Applying 3-dimensional Guidance Forces Using TPAD.

PubMed

Kang, Jiyeon; Vashista, Vineet; Agrawal, Sunil K

2017-09-01

Pelvic movement is important to human locomotion as the center of mass is located near the center of pelvis. Lateral pelvic motion plays a crucial role to shift the center of mass on the stance leg, while swinging the other leg and keeping the body balanced. In addition, vertical pelvic movement helps to reduce metabolic energy expenditure by exchanging potential and kinetic energy during the gait cycle. However, patient groups with cerebral palsy or stroke have excessive pelvic motion that leads to high energy expenditure. In addition, they have higher chances of falls as the center ofmass could deviate outside the base of support. In this paper, a novel control method is suggested using tethered pelvic assist device (TPAD) to teach subjects to walk with a specified target pelvic trajectory while walking on a treadmill. In this method, a force field is applied to the pelvis to guide it to move on a target trajectory and correctional forces are applied, if the pelvis motion has excessive deviations from the target trajectory. Three different experimentswith healthy subjects were conducted to teach them to walk on a new target pelvic trajectory with the presented control method. For all three experiments, the baseline trajectory of the pelvis was experimentally determined for each participating subject. To design a target pelvic trajectory which is different from the baseline, Experiment I scaled up the lateral component of the baseline pelvic trajectory, while Experiment II scaled down the lateral component of the baseline trajectory. For both Experiments I and II, the controller generated a 2-D force field in the transverse plane to provide the guidance force. In this paper, seven subjects were recruited for each experiment who walked on the treadmill with suggested control methods and visual feedback of their pelvic trajectory. The results show that the subjects were able to learn the target pelvic trajectory in each experiment and also retained the training effects after the completion of the experiment. In Experiment III, both lateral and vertical components of the pelvic trajectory were scaled down from the baseline trajectory. The force field was extended to three dimensions in order to correct the vertical pelvic movement as well. Three subgroups (force feedback alone, visual feedback alone, and both force and visual feedback) were recruited to understand the effects of force feedback and visual feedback alone to distinguish the results from Experiments I and II. The results showthat a trainingmethod that combines visual and force feedback is superior to the training methods with visual or force feedback alone. We believe that the present control strategy holds potential in training and correcting abnormal pelvic movements in different patient populations.

Striving to be known by significant others: automatic activation of self-verification goals in relationship contexts.

PubMed

Kraus, Michael W; Chen, Serena

2009-07-01

Extending research on the automatic activation of goals associated with significant others, the authors hypothesized that self-verification goals typically pursued with significant others are automatically elicited when a significant-other representation is activated. Supporting this hypothesis, the activation of a significant-other representation through priming (Experiments 1 and 3) or through a transference encounter (Experiment 2) led participants to seek feedback that verifies their preexisting self-views. Specifically, significant-other primed participants desired self-verifying feedback, in general (Experiment 1), from an upcoming interaction partner (Experiment 2), and relative to acquaintance-primed participants and favorable feedback (Experiment 3). Finally, self-verification goals were activated, especially for relational self-views deemed high in importance to participants' self-concepts (Experiment 2) and held with high certainty (Experiment 3). Implications for research on self-evaluative goals, the relational self, and the automatic goal activation literature are discussed, as are consequences for close relationships. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

How does audit and feedback influence intentions of health professionals to improve practice? A laboratory experiment and field study in cardiac rehabilitation.

PubMed

Gude, Wouter T; van Engen-Verheul, Mariëtte M; van der Veer, Sabine N; de Keizer, Nicolette F; Peek, Niels

2017-04-01

To identify factors that influence the intentions of health professionals to improve their practice when confronted with clinical performance feedback, which is an essential first step in the audit and feedback mechanism. We conducted a theory-driven laboratory experiment with 41 individual professionals, and a field study in 18 centres in the context of a cluster-randomised trial of electronic audit and feedback in cardiac rehabilitation. Feedback reports were provided through a web-based application, and included performance scores and benchmark comparisons (high, intermediate or low performance) for a set of process and outcome indicators. From each report participants selected indicators for improvement into their action plan. Our unit of observation was an indicator presented in a feedback report (selected yes/no); we considered selecting an indicator to reflect an intention to improve. We analysed 767 observations in the laboratory experiment and 614 in the field study, respectively. Each 10% decrease in performance score increased the probability of an indicator being selected by 54% (OR, 1.54; 95% CI 1.29% to 1.83%) in the laboratory experiment, and 25% (OR, 1.25; 95% CI 1.13% to 1.39%) in the field study. Also, performance being benchmarked as low and intermediate increased this probability in laboratory settings. Still, participants ignored the benchmarks in 34% (laboratory experiment) and 48% (field study) of their selections. When confronted with clinical performance feedback, performance scores and benchmark comparisons influenced health professionals' intentions to improve practice. However, there was substantial variation in these intentions, because professionals disagreed with benchmarks, deemed improvement unfeasible or did not consider the indicator an essential aspect of care quality. These phenomena impede intentions to improve practice, and are thus likely to dilute the effects of audit and feedback interventions. NTR3251, pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Setting out the Role of Feedback in the Assessment Process through Both the Student and Tutor Perspective

ERIC Educational Resources Information Center

Hepplestone, Stuart; Glover, Ian; Irwin, Brian; Parkin, Helen J.

2016-01-01

Despite assessment and feedback being important elements of the student experience, it is not clear how students connect these two elements together to improve their learning. What are students doing with the assignment feedback that they receive from tutors, and how do they make use of this feedback in their future assessments? A research study…

The Use of Video Technology for Providing Feedback to Students: Can It Enhance the Feedback Experience for Staff and Students?

ERIC Educational Resources Information Center

Crook, Anne; Mauchline, Alice; Maw, Stephen; Lawson, Clare; Drinkwater, Robyn; Lundqvist, Karsten; Orsmond, Paul; Gomez, Stephen; Park, Julian

2012-01-01

There are numerous issues surrounding the provision of assessment-related feedback in Higher Education, which in recent years have been highlighted in the National Student Survey. In this paper questionnaire data from staff and students at the University of Reading are used to confirm the main issues encountered with feedback, namely problems of…

Social Media and Peer Feedback: What Do Students Really Think about Using Wiki and Facebook as Platforms for Peer Feedback?

ERIC Educational Resources Information Center

Demirbilek, Muhammet

2015-01-01

Web 2.0 tools are becoming increasingly pervasive in higher education, and as a result, there is increasing interest in the use of online feedback activities. This study investigated students' actual experiences and perceptions using social media, Wiki and Facebook, tools to provide peer feedback on students' instructional material projects and to…

Delayed Intermodal Contingency Affects Young Children's Recognition of Their Current Self

ERIC Educational Resources Information Center

Miyazaki, Michiko; Hiraki, Kazuo

2006-01-01

This study investigated whether 2-, 3-, and 4-year-olds use their video feedback as a reflection of their current state, even when their feedback was presented with a short temporal delay. In Experiment 1, the effects of 1- and 2-s delayed feedback were examined on an analog of the mark test. In the case of live and 1-s delayed feedback,…

Reconstruction du Flux d'Energie et Recherche de Squarks et Gluinos dans l'Experience D0 (in French)

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

Ridel, Melissa

2002-01-01

Le modèle standard décrit la matière et les interactions fondamentales qui la gouvernent (électromagnétique, faible et forte). L'analyse des données accumulées jusqu'à présent conffrme ces prédictions notamment les mesures de précision effectuées à LEP. Malgré tout, il doit se confronter à quelques dicultés théoriques qui laisseraient penser que le Modèle Standard n'est que la théorie effective d'une autre théorie à plus haute énergie....

A qualitative study of the variable effects of audit and feedback in the ICU.

PubMed

Sinuff, Tasnim; Muscedere, John; Rozmovits, Linda; Dale, Craig M; Scales, Damon C

2015-06-01

Audit and feedback is integral to performance improvement and behaviour change in the intensive care unit (ICU). However, there remain large gaps in our understanding of the social experience of audit and feedback and the mechanisms whereby it can be optimised as a quality improvement strategy in the ICU setting. We conducted a modified grounded theory qualitative study. Seventy-two clinicians from five academic and five community ICUs in Ontario, Canada, were interviewed. Team members reviewed interview transcripts independently. Data analysis used constant comparative methods. Clinicians interviewed experienced audit and feedback as fragmented and variable in its effectiveness. Moreover, clinicians felt disconnected from the process. The audit process was perceived as being insufficiently transparent. Feedback was often untimely, incomplete and not actionable. Specific groups such as respiratory therapists and night-shift clinicians felt marginalised. Suggestions for improvement included improving information sharing about the rationale for change and the audit process, tools and metrics; implementing peer-to-peer quality discussions to avoid a top-down approach (eg, incorporating feedback into discussions at daily rounds); providing effective feedback which contains specific, transparent and actionable information; delivering timely feedback (ie, balancing feedback proximate to events with trends over time) and increasing engagement by senior management. ICU clinicians experience audit and feedback as fragmented communication with feedback being especially problematic. Attention to improving communication, integration of the process into daily clinical activities and making feedback timely, specific and actionable may increase the effectiveness of audit and feedback to affect desired change. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Feedback in Clinical Education, Part II: Approved Clinical Instructor and Student Perceptions of and Influences on Feedback

PubMed Central

Nottingham, Sara; Henning, Jolene

2014-01-01

Context: Approved Clinical Instructors (ACIs; now known as preceptors) are expected to provide feedback to athletic training students (ATSs) during clinical education experiences. Researchers in other fields have found that clinical instructors and students often have different perceptions of actual and ideal feedback and that several factors may influence the feedback exchanges between instructors and students. However, understanding of these issues in athletic training education is minimal. Objective: To investigate the current characteristics and perceptions of and the influences on feedback exchanges between ATSs and ACIs. Design: Qualitative study. Setting: One entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. Patients or Other Participants: Four ACIs and 4 second-year ATSs. Data Collection and Analysis: Individual, semistructured interviews were conducted with participants and integrated with field notes and observations for analysis. We used the constant comparative approach to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. Results: Participants described that feedback plays an important role in clinical education and has several purposes related to improving performance. The ACIs and ATSs also discussed several preferred characteristics of feedback. Participants identified 4 main influences on their feedback exchanges, including the ACI, the ATS, personalities, and the learning environment. Conclusions: The ACIs and ATSs had similar perceptions of ideal feedback in addition to the actual feedback that was provided during their clinical education experiences. Most of the preferences for feedback were aligned with recommendations in the literature, suggesting that existing research findings are applicable to athletic training clinical education. Several factors influenced the feedback exchanges between ACIs and ATSs, which clinical education coordinators should consider when selecting clinical sites and training ACIs. PMID:24151809

Feedback in clinical education, part II: Approved clinical instructor and student perceptions of and influences on feedback.

PubMed

Nottingham, Sara; Henning, Jolene

2014-01-01

Approved Clinical Instructors (ACIs; now known as preceptors) are expected to provide feedback to athletic training students (ATSs) during clinical education experiences. Researchers in other fields have found that clinical instructors and students often have different perceptions of actual and ideal feedback and that several factors may influence the feedback exchanges between instructors and students. However, understanding of these issues in athletic training education is minimal. To investigate the current characteristics and perceptions of and the influences on feedback exchanges between ATSs and ACIs. Qualitative study. One entry-level master's degree program accredited by the Commission on Accreditation of Athletic Training Education. Four ACIs and 4 second-year ATSs. Individual, semistructured interviews were conducted with participants and integrated with field notes and observations for analysis. We used the constant comparative approach to inductively analyze data and develop codes and categories. Member checking, triangulation, and peer debriefing were used to promote trustworthiness of the study. Participants described that feedback plays an important role in clinical education and has several purposes related to improving performance. The ACIs and ATSs also discussed several preferred characteristics of feedback. Participants identified 4 main influences on their feedback exchanges, including the ACI, the ATS, personalities, and the learning environment. The ACIs and ATSs had similar perceptions of ideal feedback in addition to the actual feedback that was provided during their clinical education experiences. Most of the preferences for feedback were aligned with recommendations in the literature, suggesting that existing research findings are applicable to athletic training clinical education. Several factors influenced the feedback exchanges between ACIs and ATSs, which clinical education coordinators should consider when selecting clinical sites and training ACIs.

Healthcare professional and patient codesign and validation of a mechanism for service users to feedback patient safety experiences following a care transfer: a qualitative study

PubMed Central

Scott, Jason; Heavey, Emily; Waring, Justin; Jones, Diana; Dawson, Pamela

2016-01-01

Objective To develop and validate a mechanism for patients to provide feedback on safety experiences following a care transfer between organisations. Design Qualitative study using participatory methods (codesign workshops) and cognitive interviews. Workshop data were analysed concurrently with participants, and cognitive interviews were thematically analysed using a deductive approach based on the developed feedback mechanism. Participants Expert patients (n=5) and healthcare professionals (n=11) were recruited purposively to develop the feedback mechanism in 2 workshops. Workshop 1 explored principles underpinning safety feedback mechanisms, and workshop 2 included the practical development of the feedback mechanism. Final design and content of the feedback mechanism (a safety survey) were verified by workshop participants, and cognitive interviews (n=28) were conducted with patients. Results Workshop participants identified that safety feedback mechanisms should be patient-centred, short and concise with clear signposting on how to complete, with an option to be anonymous and balanced between positive (safe) and negative (unsafe) experiences. The agreed feedback mechanism consisted of a survey split across 3 stages of the care transfer: departure, journey and arrival. Care across organisational boundaries was recognised as being complex, with healthcare professionals acknowledging the difficulty implementing changes that impact other organisations. Cognitive interview participants agreed the content of the survey was relevant but identified barriers to completion relating to the survey formatting and understanding of a care transfer. Conclusions Participatory, codesign principles helped overcome differences in understandings of safety in the complex setting of care transfers when developing a safety survey. Practical barriers to the survey's usability and acceptability to patients were identified, resulting in a modified survey design. Further research is required to determine the usability and acceptability of the survey to patients and healthcare professionals, as well as identifying how governance structures should accommodate patient feedback when relating to multiple health or social care providers. PMID:27406641

Flight-test experience in digital control of a remotely piloted vehicle.

NASA Technical Reports Server (NTRS)

Edwards, J. W.

1972-01-01

The development of a remotely piloted vehicle system consisting of a remote pilot cockpit and a ground-based digital computer coupled to the aircraft through telemetry data links is described. The feedback control laws are implemented in a FORTRAN program. Flight-test experience involving high feedback gain limits for attitude and attitude rate feedback variables, filtering of sampled data, and system operation during intermittent telemetry data link loss is discussed. Comparisons of closed-loop flight tests with analytical calculations, and pilot comments on system operation are included.

The use of laboratory experiments for the study of conservative solute transport in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Silliman, S. E.; Zheng, L.; Conwell, P.

Laboratory experiments on heterogeneous porous media (otherwise known as intermediate scale experiments, or ISEs) have been increasingly relied upon by hydrogeologists for the study of saturated and unsaturated groundwater systems. Among the many ongoing applications of ISEs is the study of fluid flow and the transport of conservative solutes in correlated permeability fields. Recent advances in ISE design have provided the capability of creating correlated permeability fields in the laboratory. This capability is important in the application of ISEs for the assessment of recent stochastic theories. In addition, pressure-transducer technology and visualization methods have provided the potential for ISEs to be used in characterizing the spatial distributions of both hydraulic head and local water velocity within correlated permeability fields. Finally, various methods are available for characterizing temporal variations in the spatial distribution (and, thereby, the spatial moments) of solute concentrations within ISEs. It is concluded, therefore, that recent developments in experimental techniques have provided an opportunity to use ISEs as important tools in the continuing study of fluid flow and the transport of conservative solutes in heterogeneous, saturated porous media. Résumé Les hydrogéologues se sont progressivement appuyés sur des expériences de laboratoire sur des milieux poreux hétérogènes (connus aussi par l'expression "Expériences àéchelle intermédiaire", ISE) pour étudier les zones saturées et non saturées des aquifères. Parmi les nombreuses applications en cours des ISE, il faut noter l'étude de l'écoulement de fluide et le transport de solutés conservatifs dans des champs aux perméabilités corrélées. Les récents progrès du protocole des ISE ont donné la possibilité de créer des champs de perméabilités corrélées au laboratoire. Cette possibilité est importante dans l'application des ISE pour l'évaluation des théories stochastiques récentes. En outre, la technologie des capteurs de pression et les méthodes de visualisation donnent la possibilité d'utiliser les ISE pour caractériser les distributions spatiales à la fois de la piézométrie et de la vitesse locale de l'eau dans un champs de perméabilités corrélées. Finalement, des méthodes variées peuvent être utilisées pour caractériser les variations temporelles de la distribution spatiale (et, par conséquent, les moments spatiaux) des concentrations de soluté dans les ISE. En conclusion, donc, des développements récents des techniques expérimentales ont fourni l'occasion d'utiliser les ISE comme d'importants outils d'étude en continu des écoulement de fluides et de transport de solutés conservatifs dans des milieux poreux saturés hétérogènes. Resumen Los experimentos de laboratorio en medio poroso heterogéneo (conocidos como Experimentos a Escala Intermedia o ISE) están cada vez mejor considerados para el estudio de los sistemas saturados y no saturados. Entre las muchas aplicaciones de los ISE se encuentra el estudio del flujo y el transporte de solutos conservativos en medios con permeabilidad que presentan una cierta estructura de correlación. Avances recientes en el diseño de los ISE han proporcionado la capacidad de crear medios de este tipo en el laboratorio. Esta capacidad es importante para la aplicación de los ISE a la evaluación de las teorías estocásticas recientes. Además, la tecnología de los transductores de presión y los métodos de visualización han permitido que los ISE se usen para caracterizar la distribución espacial de niveles hidráulicos y de las velocidades locales del agua en campos de permeabilidad con determinada correlación espacial. Finalmente, existen varios métodos para caracterizar las variaciones temporales en la distribución espacial (y por tanto los momentos estadísticos espaciales) de la concentración de solutos en los ISE. Se concluye que los desarrollos recientes en las técnicas experimentales han proporcionado una oportunidad para usar los ISE como herramientas fundamentales en el estudio del flujo y transporte de solutos conservativos en medio poroso heterogéneo y saturado.

Academic Feedback in Veterinary Medicine: A comparison of School Leaver and Graduate Entry cohorts

ERIC Educational Resources Information Center

Hughes, Kirsty Jean; McCune, Velda; Rhind, Susan

2013-01-01

This study analysed the expectations and experiences of students on a five-year undergraduate ("n"?=?91) and four-year graduate entry ("n"?=?47) veterinary medicine degree programme relating to academic feedback. Qualitative and quantitative methodologies were used to explore new students' expectations and prior experiences of…

Online Collaborative Writing for ESL Learners Using Blogs and Feedback Checklists

ERIC Educational Resources Information Center

Grami, Grami Mohammad A.

2012-01-01

This paper reports on the experience of seven Saudi female ESL students who worked collaboratively in an interactive online writing environment over a period of four weeks. It chronicles their experiences with online writing tasks, documents their responses to online feedback, and examines their attempts to cope with different settings and…

Undergraduate Student Responses to Feedback: Expectations and Experiences

ERIC Educational Resources Information Center

Small, Felicity; Attree, Kath

2016-01-01

This research is a qualitative exploration of first and second year university students' experiences of feedback, specifically focused on their expectations and feelings. The data (n = 46) were collected from internal and distance-learning students in their first or second year, who are of lower socio-economic status and first in family to attend.…

Communicating Feedback in Teaching Practice Supervision in a Learning-Oriented Field Experience Assessment Framework

ERIC Educational Resources Information Center

Tang, Sylvia Yee Fang; Chow, Alice Wai Kwan

2007-01-01

This article seeks to understand the ways in which feedback was communicated in post-observation conferences in teaching practice supervision within the learning-oriented field experience assessment (LOFEA) framework. 32 post-observation conferences between 21 pairs of supervisors and participants of in-service teacher education programmes, and…

Measurements and Computations of Flow in an Urban Street System

NASA Astrophysics Data System (ADS)

Castro, Ian P.; Xie, Zheng-Tong; Fuka, V.; Robins, Alan G.; Carpentieri, M.; Hayden, P.; Hertwig, D.; Coceal, O.

2017-02-01

We present results from laboratory and computational experiments on the turbulent flow over an array of rectangular blocks modelling a typical, asymmetric urban canopy at various orientations to the approach flow. The work forms part of a larger study on dispersion within such arrays (project DIPLOS) and concentrates on the nature of the mean flow and turbulence fields within the canopy region, recognising that unless the flow field is adequately represented in computational models there is no reason to expect realistic simulations of the nature of the dispersion of pollutants emitted within the canopy. Comparisons between the experimental data and those obtained from both large-eddy simulation (LES) and direct numerical simulation (DNS) are shown and it is concluded that careful use of LES can produce generally excellent agreement with laboratory and DNS results, lending further confidence in the use of LES for such situations. Various crucial issues are discussed and advice offered to both experimentalists and those seeking to compute canopy flows with turbulence resolving models.

Large-eddy simulation of turbulent cavitating flow in a micro channel

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

Egerer, Christian P., E-mail: christian.egerer@aer.mw.tum.de; Hickel, Stefan; Schmidt, Steffen J.

2014-08-15

Large-eddy simulations (LES) of cavitating flow of a Diesel-fuel-like fluid in a generic throttle geometry are presented. Two-phase regions are modeled by a parameter-free thermodynamic equilibrium mixture model, and compressibility of the liquid and the liquid-vapor mixture is taken into account. The Adaptive Local Deconvolution Method (ALDM), adapted for cavitating flows, is employed for discretizing the convective terms of the Navier-Stokes equations for the homogeneous mixture. ALDM is a finite-volume-based implicit LES approach that merges physically motivated turbulence modeling and numerical discretization. Validation of the numerical method is performed for a cavitating turbulent mixing layer. Comparisons with experimental data ofmore » the throttle flow at two different operating conditions are presented. The LES with the employed cavitation modeling predicts relevant flow and cavitation features accurately within the uncertainty range of the experiment. The turbulence structure of the flow is further analyzed with an emphasis on the interaction between cavitation and coherent motion, and on the statistically averaged-flow evolution.« less

Large-eddy and unsteady RANS simulations of a shock-accelerated heavy gas cylinder

DOE PAGES

Morgan, B. E.; Greenough, J. A.

2015-04-08

Two-dimensional numerical simulations of the Richtmyer–Meshkov unstable “shock-jet” problem are conducted using both large-eddy simulation (LES) and unsteady Reynolds-averaged Navier–Stokes (URANS) approaches in an arbitrary Lagrangian–Eulerian hydrodynamics code. Turbulence statistics are extracted from LES by running an ensemble of simulations with multimode perturbations to the initial conditions. Detailed grid convergence studies are conducted, and LES results are found to agree well with both experiment and high-order simulations conducted by Shankar et al. (Phys Fluids 23, 024102, 2011). URANS results using a k–L approach are found to be highly sensitive to initialization of the turbulence lengthscale L and to the timemore » at which L becomes resolved on the computational mesh. As a result, it is observed that a gradient diffusion closure for turbulent species flux is a poor approximation at early times, and a new closure based on the mass-flux velocity is proposed for low-Reynolds-number mixing.« less

Large Eddy Simulation including population dynamics model for polydisperse droplet evolution

NASA Astrophysics Data System (ADS)

Aiyer, Aditya; Yang, Di; Chamecki, Marcelo; Meneveau, Charles

2017-11-01

Previous studies have shown that dispersion patterns of oil droplets in the ocean following a deep sea oil spill depend critically on droplet diameter. Hence predicting the evolution of the droplet size distribution is of critical importance for predicting macroscopic features of dispersion in the ocean. We adopt a population dynamics model of polydisperse droplet distributions for use in LES. We generalize a breakup model from Reynolds averaging approaches to LES in which the breakup is modeled as due to bombardment of droplets by turbulent eddies of various sizes. The breakage rate is expressed as an integral of a collision frequency times a breakage efficiency over all eddy sizes. An empirical fit to the integral is proposed in order to avoid having to recalculate the integral at every LES grid point and time step. The fit is tested by comparison with various stirred tank experiments. As a flow application for LES we consider a jet of bubbles and large droplets injected at the bottom of the tank. The advected velocity and concentration fields of the drops are described using an Eulerian approach. We study the change of the oil droplet distribution due to breakup caused by interaction of turbulence with the oil droplets. This research was made possible by a Grant from the Gulf of Mexico Research Initiative.

The benefits of computer-generated feedback for mathematics problem solving.

PubMed

Fyfe, Emily R; Rittle-Johnson, Bethany

2016-07-01

The goal of the current research was to better understand when and why feedback has positive effects on learning and to identify features of feedback that may improve its efficacy. In a randomized experiment, second-grade children received instruction on a correct problem-solving strategy and then solved a set of relevant problems. Children were assigned to receive no feedback, immediate feedback, or summative feedback from the computer. On a posttest the following day, feedback resulted in higher scores relative to no feedback for children who started with low prior knowledge. Immediate feedback was particularly effective, facilitating mastery of the material for children with both low and high prior knowledge. Results suggest that minimal computer-generated feedback can be a powerful form of guidance during problem solving. Copyright © 2016 Elsevier Inc. All rights reserved.

A Comparison of Electronic and Paper-Based Assignment Submission and Feedback

ERIC Educational Resources Information Center

Bridge, Pete; Appleyard, Rob

2008-01-01

This paper presents the results of a study evaluating student perceptions of online assignment submission. 47 students submitted assignments and received feedback via features within the Virtual Learning Environment Blackboard[TM]. The students then completed questionnaires comparing their experience of online submission and feedback with…

75 FR 26345 - Agency Information Collection (Ethics Consultation Feedback Tool (ECFT)) New Enrollee Survey...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-11

... Collection (Ethics Consultation Feedback Tool (ECFT)) New Enrollee Survey) Activity Under OMB Review AGENCY...).'' SUPPLEMENTARY INFORMATION: Title: Ethics Consultation Feedback Tool (ECFT), VA Form 10-0502. OMB Control Number... collect data from patients and family members about their experience during the Ethics Consultation...

Feedback and Sentence Learning.

ERIC Educational Resources Information Center

Guthrie, John T.

The theoretical functions of external feedback in SR and closed loop models of verbal learning are presented. Contradictory predictions from the models are tested with a three by three factorial experiment including three types of feedback and three amounts of rehearsal. There were 90 adult students run individually and they were required to learn…

Feedback for Thought: Examining the Influence of Feedback Constituents on Learning Experience

ERIC Educational Resources Information Center

Aoun, Chadi; Vatanasakdakul, Savanid; Ang, Karyne

2018-01-01

Reflective teaching practice is often heralded as a pillar of effective tuition. However, the perceptions of multiple forms of feedback among learners and their contributions to reflective learning is yet to attract significant attention, particularly in the Information Systems (IS) context. This research investigates the antecedent constituents…

Proprioceptive role for palisade endings in extraocular muscles: evidence from the Jendrassik Maneuver.

PubMed

Niechwiej-Szwedo, E; González, E; Bega, S; Verrier, M C; Wong, A M; Steinbach, M J

2006-07-01

A proprioceptive hypothesis for the control of eye movements has been recently proposed based on neuroanatomical tracing studies. It has been suggested that the non-twitch motoneurons could be involved in modulating the gain of sensory feedback from the eye muscles analogous to the gamma (gamma) motoneurons which control the gain of proprioceptive feedback in skeletal muscles. We conducted behavioral and psychophysical experiments to test the above hypothesis using the Jendrassik Maneuver (JM) to alter the activity of gamma motoneurons. It was hypothesized that the JM would alter the proprioceptive feedback from the eye muscles which would result in misregistration of eye position and mislocalization of targets. In the first experiment, vergence eye movements and pointing responses were examined. Data showed that the JM affected the localization responses but not the actual eye position. Perceptual judgments were tested in the second experiment, and the results showed that targets were perceived as farther when the afferent feedback was altered by the JM. Overall, the results from the two experiments showed that eye position was perceived as more divergent with the JM, but the actual eye movements were not affected. We tested this further in Experiment 3 by examining the effect of JM on the amplitude and velocity of saccadic eye movements. As expected, there were no significant differences in saccadic parameters between the control and experimental conditions. Overall, the present study provides novel insight into the mechanism which may be involved in the use of sensory feedback from the eye muscles. Data from the first two experiments support the hypothesis that the JM alters the registered eye position, as evidenced by the localization errors. We propose that the altered eye position signal is due to the effect of the JM which changes the gain of the sensory feedback from the eye muscles, possibly via the activity of non-twitch motoneurons.

The use of patient experience survey data by out-of-hours primary care services: a qualitative interview study.

PubMed

Barry, Heather E; Campbell, John L; Asprey, Anthea; Richards, Suzanne H

2016-11-01

English National Quality Requirements mandate out-of-hours primary care services to routinely audit patient experience, but do not state how it should be done. We explored how providers collect patient feedback data and use it to inform service provision. We also explored staff views on the utility of out-of-hours questions from the English General Practice Patient Survey (GPPS). A qualitative study was conducted with 31 staff (comprising service managers, general practitioners and administrators) from 11 out-of-hours primary care providers in England, UK. Staff responsible for patient experience audits within their service were sampled and data collected via face-to-face semistructured interviews. Although most providers regularly audited their patients' experiences by using patient surveys, many participants expressed a strong preference for additional qualitative feedback. Staff provided examples of small changes to service delivery resulting from patient feedback, but service-wide changes were not instigated. Perceptions that patients lacked sufficient understanding of the urgent care system in which out-of-hours primary care services operate were common and a barrier to using feedback to enable change. Participants recognised the value of using patient experience feedback to benchmark services, but perceived weaknesses in the out-of-hours items from the GPPS led them to question the validity of using these data for benchmarking in its current form. The lack of clarity around how out-of-hours providers should audit patient experience hinders the utility of the National Quality Requirements. Although surveys were common, patient feedback data had only a limited role in service change. Data derived from the GPPS may be used to benchmark service providers, but refinement of the out-of-hours items is needed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Oxytocin selectively facilitates learning with social feedback and increases activity and functional connectivity in emotional memory and reward processing regions.

PubMed

Hu, Jiehui; Qi, Song; Becker, Benjamin; Luo, Lizhu; Gao, Shan; Gong, Qiyong; Hurlemann, René; Kendrick, Keith M

2015-06-01

In male Caucasian subjects, learning is facilitated by receipt of social compared with non-social feedback, and the neuropeptide oxytocin (OXT) facilitates this effect. In this study, we have first shown a cultural difference in that male Chinese subjects actually perform significantly worse in the same reinforcement associated learning task with social (emotional faces) compared with non-social feedback. Nevertheless, in two independent double-blind placebo (PLC) controlled between-subject design experiments we found OXT still selectively facilitated learning with social feedback. Similar to Caucasian subjects this OXT effect was strongest with feedback using female rather than male faces. One experiment performed in conjunction with functional magnetic resonance imaging showed that during the response, but not feedback phase of the task, OXT selectively increased activity in the amygdala, hippocampus, parahippocampal gyrus and putamen during the social feedback condition, and functional connectivity between the amygdala and insula and caudate. Therefore, OXT may be increasing the salience and reward value of anticipated social feedback. In the PLC group, response times and state anxiety scores during social feedback were associated with signal changes in these same regions but not in the OXT group. OXT may therefore have also facilitated learning by reducing anxiety in the social feedback condition. Overall our results provide the first evidence for cultural differences in social facilitation of learning per se, but a similar selective enhancement of learning with social feedback under OXT. This effect of OXT may be associated with enhanced responses and functional connectivity in emotional memory and reward processing regions. © 2015 Wiley Periodicals, Inc.

New MHD feedback control schemes using the MARTe framework in RFX-mod

NASA Astrophysics Data System (ADS)

Piron, Chiara; Manduchi, Gabriele; Marrelli, Lionello; Piovesan, Paolo; Zanca, Paolo

2013-10-01

Real-time feedback control of MHD instabilities is a topic of major interest in magnetic thermonuclear fusion, since it allows to optimize a device performance even beyond its stability bounds. The stability properties of different magnetic configurations are important test benches for real-time control systems. RFX-mod, a Reversed Field Pinch experiment that can also operate as a tokamak, is a well suited device to investigate this topic. It is equipped with a sophisticated magnetic feedback system that controls MHD instabilities and error fields by means of 192 active coils and a corresponding grid of sensors. In addition, the RFX-mod control system has recently gained new potentialities thanks to the introduction of the MARTe framework and of a new CPU architecture. These capabilities allow to study new feedback algorithms relevant to both RFP and tokamak operation and to contribute to the debate on the optimal feedback strategy. This work focuses on the design of new feedback schemes. For this purpose new magnetic sensors have been explored, together with new algorithms that refine the de-aliasing computation of the radial sideband harmonics. The comparison of different sensor and feedback strategy performance is described in both RFP and tokamak experiments.

Dual-learning systems during speech category learning

PubMed Central

Chandrasekaran, Bharath; Yi, Han-Gyol; Maddox, W. Todd

2013-01-01

Dual-systems models of visual category learning posit the existence of an explicit, hypothesis-testing ‘reflective’ system, as well as an implicit, procedural-based ‘reflexive’ system. The reflective and reflexive learning systems are competitive and neurally dissociable. Relatively little is known about the role of these domain-general learning systems in speech category learning. Given the multidimensional, redundant, and variable nature of acoustic cues in speech categories, our working hypothesis is that speech categories are learned reflexively. To this end, we examined the relative contribution of these learning systems to speech learning in adults. Native English speakers learned to categorize Mandarin tone categories over 480 trials. The training protocol involved trial-by-trial feedback and multiple talkers. Experiment 1 and 2 examined the effect of manipulating the timing (immediate vs. delayed) and information content (full vs. minimal) of feedback. Dual-systems models of visual category learning predict that delayed feedback and providing rich, informational feedback enhance reflective learning, while immediate and minimally informative feedback enhance reflexive learning. Across the two experiments, our results show feedback manipulations that targeted reflexive learning enhanced category learning success. In Experiment 3, we examined the role of trial-to-trial talker information (mixed vs. blocked presentation) on speech category learning success. We hypothesized that the mixed condition would enhance reflexive learning by not allowing an association between talker-related acoustic cues and speech categories. Our results show that the mixed talker condition led to relatively greater accuracies. Our experiments demonstrate that speech categories are optimally learned by training methods that target the reflexive learning system. PMID:24002965

Large Eddy Simulation of Cirrus Clouds

NASA Technical Reports Server (NTRS)

Wu, Ting; Cotton, William R.

1999-01-01

The Regional Atmospheric Modeling System (RAMS) with mesoscale interactive nested-grids and a Large-Eddy Simulation (LES) version of RAMS, coupled to two-moment microphysics and a new two-stream radiative code were used to investigate the dynamic, microphysical, and radiative aspects of the November 26, 1991 cirrus event. Wu (1998) describes the results of that research in full detail and is enclosed as Appendix 1. The mesoscale nested grid simulation successfully reproduced the large scale circulation as compared to the Mesoscale Analysis and Prediction System's (MAPS) analyses and other observations. Three cloud bands which match nicely to the three cloud lines identified in an observational study (Mace et al., 1995) are predicted on Grid #2 of the nested grids, even though the mesoscale simulation predicts a larger west-east cloud width than what was observed. Large-eddy simulations (LES) were performed to study the dynamical, microphysical, and radiative processes in the 26 November 1991 FIRE 11 cirrus event. The LES model is based on the RAMS version 3b developed at Colorado State University. It includes a new radiation scheme developed by Harrington (1997) and a new subgrid scale model developed by Kosovic (1996). The LES model simulated a single cloud layer for Case 1 and a two-layer cloud structure for Case 2. The simulations demonstrated that latent heat release can play a significant role in the formation and development of cirrus clouds. For the thin cirrus in Case 1, the latent heat release was insufficient for the cirrus clouds to become positively buoyant. However, in some special cases such as Case 2, positively buoyant cells can be embedded within the cirrus layers. These cells were so active that the rising updraft induced its own pressure perturbations that affected the cloud evolution. Vertical profiles of the total radiative and latent heating rates indicated that for well developed, deep, and active cirrus clouds, radiative cooling and latent heating could be comparable in magnitude in the cloudy layer. This implies that latent heating cannot be neglected in the construction of a cirrus cloud model. The probability density function (PDF) of w was analyzed to assist in the parameterization of cloud-scale velocities in large-scale models. For the more radiatively-driven, thin cirrus case, the PDFs are approximately Gaussian. However, in the interior of the deep, convectively unstable case, the PDFs of w are multi-modal and very broad, indicating that parameterizing cloud-scale motions for such clouds can be very challenging. The results of this research are described in detail in a paper submitted to the Journal of Atmospheric Science (Wu and Cotton, 1999), which is enclosed as Appendix 2. Using soundings extracted from a mesoscale simulation of the November 26, 1991 cirrus event, the radiative effects on vapor deposition/sublimation of ice crystals was studied using a two-dimensional cloud-resolving model (CRM) version of RAMS, coupled to an explicit bin-resolving microphysics. The CRM simulations of the November 26, 1991 cirrus event demonstrate that the radiative impact on the diffusional growth (or sublimation) of ice crystals is significant. In this case, the ice particles experienced radiative warming. Model results show that radiative feedbacks in the diffusional growth of ice particles can be very complex. Radiative warming of an ice particle will restrict the particle's diffusional growth. In the case of radiative warming, ice particles larger than a certain size will experience so much radiative warming that surface ice saturation vapor pressures become large enough to cause sublimation of the larger crystals, while smaller crystals are growing by vapor deposition. However, ice mass production can be enhanced in the case of radiative cooling of an ice particle. For the November 26, 1991 cirrus event, radiative feedback results in significant reduction in the total ice mass, especially in the production of large ice crystals, and consequently, both radiative and dynamic properties of the cirrus cloud are significantly affected. A complete description of this research has been submitted as a paper to the Journal of Atmospheric Science (Wu et al., 1999), and included as Appendix 3.

Les soins aux enfants et aux adolescents des familles des militaires canadiens : les considérations particulières

PubMed Central

Rowan-Legg, Anne

2017-01-01

Résumé Les familles des militaires font face à de nombreux facteurs de stress, tels que les réinstallations fréquentes, les longues pério des de séparation familiale, l’isolement géographique du réseau de soutien de la famille élargie et le déploiement en zones très dangereuses. Les enfants et les adolescents des familles des militaires vivent les mêmes trajectoires développementales et motivationnelles que leurs homologues civils, mais ils sont également aux prises avec des pressions et des facteurs de stress liés à leur développement qui sont inhabituels et qui leur sont imposés par les exigences de la vie militaire. Les effets de la vie militaire sur les familles et les enfants commencent à être admis et mieux caractérisés. Il est essentiel de comprendre les préoccupations propres aux enfants et aux adolescents des familles des militaires et de mobiliser les ressources nécessaires pour les soutenir afin de répondre à leurs besoins en matière de santé.

Effects of realistic force feedback in a robotic assisted minimally invasive surgery system.

PubMed

Moradi Dalvand, Mohsen; Shirinzadeh, Bijan; Nahavandi, Saeid; Smith, Julian

2014-06-01

Robotic assisted minimally invasive surgery systems not only have the advantages of traditional laparoscopic procedures but also restore the surgeon's hand-eye coordination and improve the surgeon's precision by filtering hand tremors. Unfortunately, these benefits have come at the expense of the surgeon's ability to feel. Several research efforts have already attempted to restore this feature and study the effects of force feedback in robotic systems. The proposed methods and studies have some shortcomings. The main focus of this research is to overcome some of these limitations and to study the effects of force feedback in palpation in a more realistic fashion. A parallel robot assisted minimally invasive surgery system (PRAMiSS) with force feedback capabilities was employed to study the effects of realistic force feedback in palpation of artificial tissue samples. PRAMiSS is capable of actually measuring the tip/tissue interaction forces directly from the surgery site. Four sets of experiments using only vision feedback, only force feedback, simultaneous force and vision feedback and direct manipulation were conducted to evaluate the role of sensory feedback from sideways tip/tissue interaction forces with a scale factor of 100% in characterising tissues of varying stiffness. Twenty human subjects were involved in the experiments for at least 1440 trials. Friedman and Wilcoxon signed-rank tests were employed to statistically analyse the experimental results. Providing realistic force feedback in robotic assisted surgery systems improves the quality of tissue characterization procedures. Force feedback capability also increases the certainty of characterizing soft tissues compared with direct palpation using the lateral sides of index fingers. The force feedback capability can improve the quality of palpation and characterization of soft tissues of varying stiffness by restoring sense of touch in robotic assisted minimally invasive surgery operations.

Can podcasts for assessment guidance and feedback promote self-efficacy among undergraduate nursing students? A qualitative study.

PubMed

McSwiggan, Linda C; Campbell, Maureen

2017-02-01

Improving assessment guidance and feedback for students has become an international priority within higher education. Podcasts have been proposed as a tool for enhancing teaching, learning and assessment. However, a stronger theory-based rationale for using podcasts, particularly as a means of facilitating assessment guidance and feedback, is required. To explore students' experiences of using podcasts for assessment guidance and feedback. To consider how these podcasts shaped beliefs about their ability to successfully engage with, and act on, assessment guidance and feedback Design Exploratory qualitative study. Setting Higher education institution in North-East Scotland. Participants Eighteen third year undergraduate nursing students who had utilised podcasts for assessment guidance and feedback within their current programme of study. Participants took part in one of four focus groups, conducted between July and September 2013. Purposive sampling was utilised to recruit participants of different ages, gender, levels of self-assessed information technology skills and levels of academic achievement. Data analysis was guided by the framework approach. Thematic analysis highlighted similarities and differences in terms of students' experiences of using podcasts for assessment guidance and feedback. Further analysis revealed that Self-Efficacy Theory provided deeper theoretical insights into how the content, structure and delivery of podcasts can be shaped to promote more successful engagement with assessment guidance and feedback from students. The structured, logical approach of assessment guidance podcasts appeared to strengthen self-efficacy by providing readily accessible support and by helping students convert intentions into action. Students with high self-efficacy in relation to tasks associated with assessment were more likely to engage with feedback, whereas those with low self-efficacy tended to overlook opportunities to access feedback due to feelings of helplessness and futility. Adopting well-structured podcasts as an educational tool, based around the four major sources of information (performance accomplishments, vicarious experience, social persuasion, and physiological and emotional states), has potential to promote self efficacy for individuals, as well as groups of students, in terms of assessment guidance and feedback. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methodes de calcul des forces aerodynamiques pour les etudes des interactions aeroservoelastiques

NASA Astrophysics Data System (ADS)

Biskri, Djallel Eddine

L'aeroservoelasticite est un domaine ou interagissent la structure flexible d'un avion, l'aerodynamique et la commande de vol. De son cote, la commande du vol considere l'avion comme une structure rigide et etudie l'influence du systeme de commande sur la dynamique de vol. Dans cette these, nous avons code trois nouvelles methodes d'approximation de forces aerodynamiques: Moindres carres corriges, Etat minimal corrige et Etats combines. Dans les deux premieres methodes, les erreurs d'approximation entre les forces aerodynamiques approximees par les methodes classiques et celles obtenues par les nouvelles methodes ont les memes formes analytiques que celles des forces aerodynamiques calculees par LS ou MS. Quant a la troisieme methode, celle-ci combine les formulations des forces approximees avec les methodes standards LS et MS. Les vitesses et frequences de battement et les temps d'executions calcules par les nouvelles methodes versus ceux calcules par les methodes classiques ont ete analyses.

Changing Teacher Morale: An Experiment in Feedback of Identified Problems of Teachers and Principals. Final Report.

ERIC Educational Resources Information Center

Bentley, Ralph R.; Rempel, Averno M.

This 2-year study attempted to determine whether feedback to teachers and principals about problems and tensions existing in their schools can be effective in changing morale for (1) teachers generally, (2) vocational teachers, (3) and nonvocational teachers. Relationships between teacher morale and such factors as age, sex, teaching experience,…

A Dataset of Three Educational Technology Experiments on Differentiation, Formative Testing and Feedback

ERIC Educational Resources Information Center

Haelermans, Carla; Ghysels, Joris; Prince, Fernao

2015-01-01

This paper describes a dataset with data from three individually randomized educational technology experiments on differentiation, formative testing and feedback during one school year for a group of 8th grade students in the Netherlands, using administrative data and the online motivation questionnaire of Boekaerts. The dataset consists of pre-…

Listen to Your Heart: When False Somatic Feedback Shapes Moral Behavior

ERIC Educational Resources Information Center

Gu, Jun; Zhong, Chen-Bo; Page-Gould, Elizabeth

2013-01-01

A pounding heart is a common symptom people experience when confronting moral dilemmas. The authors conducted 4 experiments using a false feedback paradigm to explore whether and when listening to a fast (vs. normal) heartbeat sound shaped ethical behavior. Study 1 found that perceived fast heartbeat increased volunteering for a just cause. Study…

Recherches sur l'histoire de l'astronomie ancienne

NASA Astrophysics Data System (ADS)

Tannery, Paul

2015-04-01

Préface; 1. Ce que les Hellènes ont appelé astronomie; 2. Ce que les Hellènes ont appelé astrologie (cont.); 3. Les mathématiciens alexandrins; 4. Les postulats de l'astronomie d'après Ptlolémée et les auteurs élémentaires; 5. La sphéricité de la terre et la mesure de sa circonférence; 6. Le mouvement général des planètes; 7. Les cercles de la sphère; 8. La longueur de l'année solaire; 9. Les tables du soleil; 10. Les périodes d'Hipparque pour les mouvements lunaires; 11. Les tables de la lune; 12. Les parallaxes du soleil et de la lune; 13. Les prédictions d'éclipses; 14. La théorie des planètes; 15. Le catalogue des fixes; Appendice; Errata.

Pyff - a pythonic framework for feedback applications and stimulus presentation in neuroscience.

PubMed

Venthur, Bastian; Scholler, Simon; Williamson, John; Dähne, Sven; Treder, Matthias S; Kramarek, Maria T; Müller, Klaus-Robert; Blankertz, Benjamin

2010-01-01

This paper introduces Pyff, the Pythonic feedback framework for feedback applications and stimulus presentation. Pyff provides a platform-independent framework that allows users to develop and run neuroscientific experiments in the programming language Python. Existing solutions have mostly been implemented in C++, which makes for a rather tedious programming task for non-computer-scientists, or in Matlab, which is not well suited for more advanced visual or auditory applications. Pyff was designed to make experimental paradigms (i.e., feedback and stimulus applications) easily programmable. It includes base classes for various types of common feedbacks and stimuli as well as useful libraries for external hardware such as eyetrackers. Pyff is also equipped with a steadily growing set of ready-to-use feedbacks and stimuli. It can be used as a standalone application, for instance providing stimulus presentation in psychophysics experiments, or within a closed loop such as in biofeedback or brain-computer interfacing experiments. Pyff communicates with other systems via a standardized communication protocol and is therefore suitable to be used with any system that may be adapted to send its data in the specified format. Having such a general, open-source framework will help foster a fruitful exchange of experimental paradigms between research groups. In particular, it will decrease the need of reprogramming standard paradigms, ease the reproducibility of published results, and naturally entail some standardization of stimulus presentation.

Pyff – A Pythonic Framework for Feedback Applications and Stimulus Presentation in Neuroscience

PubMed Central

Venthur, Bastian; Scholler, Simon; Williamson, John; Dähne, Sven; Treder, Matthias S.; Kramarek, Maria T.; Müller, Klaus-Robert; Blankertz, Benjamin

2010-01-01

This paper introduces Pyff, the Pythonic feedback framework for feedback applications and stimulus presentation. Pyff provides a platform-independent framework that allows users to develop and run neuroscientific experiments in the programming language Python. Existing solutions have mostly been implemented in C++, which makes for a rather tedious programming task for non-computer-scientists, or in Matlab, which is not well suited for more advanced visual or auditory applications. Pyff was designed to make experimental paradigms (i.e., feedback and stimulus applications) easily programmable. It includes base classes for various types of common feedbacks and stimuli as well as useful libraries for external hardware such as eyetrackers. Pyff is also equipped with a steadily growing set of ready-to-use feedbacks and stimuli. It can be used as a standalone application, for instance providing stimulus presentation in psychophysics experiments, or within a closed loop such as in biofeedback or brain–computer interfacing experiments. Pyff communicates with other systems via a standardized communication protocol and is therefore suitable to be used with any system that may be adapted to send its data in the specified format. Having such a general, open-source framework will help foster a fruitful exchange of experimental paradigms between research groups. In particular, it will decrease the need of reprogramming standard paradigms, ease the reproducibility of published results, and naturally entail some standardization of stimulus presentation. PMID:21160550

SGS Dynamics and Modeling near a Rough Wall.

NASA Astrophysics Data System (ADS)

Juneja, Anurag; Brasseur, James G.

1998-11-01

Large-eddy simulation (LES) of the atmospheric boundary layer (ABL) using classical subgrid-scale (SGS) models is known to poorly predict mean shear at the first few grid cells near the rough surface, creating error which can propogate vertically to infect the entire ABL. Our goal was to determine the first-order errors in predicted SGS terms that arise as a consequence of necessary under-resolution of integral scales and anisotropy which exist at the first few grid levels in LES of rough wall turbulence. Analyzing the terms predicted from eddy-viscosity and similarity closures with DNS anisotropic datasets of buoyancy- and shear-driven turbulence, we uncover three important issues which should be addressed in the design of SGS closures for rough walls and we provide a priori tests for the SGS model. Firstly, we identify a strong spurious coupling between the anisotropic structure of the resolved velocity field and predicted SGS dynamics which can create a feedback loop to incorrectly enhance certain components of the predicted resolved velocity. Secondly, we find that eddy viscosity and similarity SGS models do not contain enough degrees of freedom to capture, at a sufficient level of accuracy, both RS-SGS energy flux and SGS-RS dynamics. Thirdly, to correctly capture pressure transport near a wall, closures must be made more flexible to accommodate proper partitioning between SGS stress divergence and SGS pressure gradient.

The characteristic black hole mass resulting from direct collapse in the early Universe

NASA Astrophysics Data System (ADS)

Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.; Niemeyer, J. C.

2013-12-01

Black holes of a billion solar masses are observed in the infant Universe a few hundred million years after the big bang. The direct collapse of protogalactic gas clouds in primordial haloes with Tvir ≥ 104 K provides the most promising way to assemble massive black holes. In this study, we aim to determine the characteristic mass scale of seed black holes and the time evolution of the accretion rates resulting from the direct collapse model. We explore the formation of supermassive black holes via cosmological large eddy simulations (LES) by employing sink particles and following their evolution for 20 000 yr after the formation of the first sink. As the resulting protostars were shown to have cool atmospheres in the presence of strong accretion, we assume here that UV feedback is negligible during this calculation. We confirm this result in a comparison run without sinks. Our findings show that black hole seeds with characteristic mass of 105 M⊙ are formed in the presence of strong Lyman-Werner flux which leads to an isothermal collapse. The characteristic mass is about two times higher in LES compared to the implicit large eddy simulations. The accretion rates increase with time and reach a maximum value of 10 M⊙ yr-1 after 104 yr. Our results show that the direct collapse model is clearly feasible as it provides the expected mass of the seed black holes.

An Anatomy of Feedback: A Phenomenographic Investigation of Undergraduate Students' Conceptions of Feedback

ERIC Educational Resources Information Center

McLean, Angela J.; Bond, Carol H.; Nicholson, Helen D.

2015-01-01

The aim of this research was to investigate how undergraduate students conceptualise feedback, and compare this with research into conceptions of teaching and learning related phenomena in higher education. Using a phenomenographic approach, 28 physiotherapy students in New Zealand were interviewed about their experiences. Data analysis resulted…

Effect of Integrated Feedback on Classroom Climate of Secondary School Teachers

ERIC Educational Resources Information Center

Patel, Nilesh Kumar

2018-01-01

This study aimed at finding out the effect of Integrated feedback on Classroom climate of secondary school teachers. This research is experimental in nature. Non-equivalent control group design suggested by Stanley and Campbell (1963) was used for the experiment. Integrated feedback was treatment and independent variable, Classroom climate was…

Motivated or Paralyzed? Individuals' Beliefs about Intelligence Influence Performance Outcome of Expecting Rapid Feedback

ERIC Educational Resources Information Center

Zhao, Qin; Zhang, Jie; Vance, Kaleigh

2013-01-01

The current research examines whether and how beliefs about intelligence moderate the effects of expecting rapid feedback on exam performance. Thirty-six undergraduates participated in a field experiment with two between-subjects independent variables: anticipated feedback proximity and beliefs about intelligence. The results show that expecting…

The Transformative Role of ePortfolios: Feedback in Healthcare Learning

ERIC Educational Resources Information Center

Peacock, Susi; Murray, Sue; Scott, Alison; Kelly, Jacquie

2011-01-01

This article reports findings of a study based in Scotland that explored healthcare learners' experiences of feedback and ePortfolios. Feedback is a highly complex, multi-dimensional phenomenon, and healthcare learners consider it essential for their learning, recognizing that without it patient safety may be compromised. This study sought to…

Improving Students with Rubric-Based Self-Assessment and Oral Feedback

ERIC Educational Resources Information Center

Barney, S.; Khurum, M.; Petersen, K.; Unterkalmsteiner, M.; Jabangwe, R.

2012-01-01

Rubrics and oral feedback are approaches to help students improve performance and meet learning outcomes. However, their effect on the actual improvement achieved is inconclusive. This paper evaluates the effect of rubrics and oral feedback on student learning outcomes. An experiment was conducted in a software engineering course on requirements…

Recasts, Metalinguistic Feedback, and Learners' Perceptions: A Case of Persian EFL Learners

ERIC Educational Resources Information Center

Rassaei, Ehsan; Moinzadeh, Ahmad

2014-01-01

In the current study, we present the results of an experiment with 30 Persian EFL learners in which we explored the learners' perceptions of recasts and metalinguistic corrective feedback. The participant learners received either recasts or metalinguistic feedback for their errors during task-based interactions with their interlocutors and then…

ESLl Teachers' Knowledge of and Experience with Written Corrective Feedback

ERIC Educational Resources Information Center

Cao, Peihong

2017-01-01

Written Corrective Feedback (WCF) in writing classes is fundamental to interactions between teachers and students about students' writing and to help students further improve their writing. As one of the main feedback sources, teachers' cognition (e.g., teachers' thoughts, knowledge, and beliefs) needs to be probed to properly understand teachers…

Student Feedback Systems in Higher Education: A Focused Literature Review and Environmental Scan

ERIC Educational Resources Information Center

Alderman, Lyn; Towers, Stephen; Bannah, Sylvia

2012-01-01

In recent times, higher education institutions have paid increasing attention to the views of students to obtain feedback on their experience of learning and teaching through internal surveys. This article reviews research in the field and reports on practices in other Australian universities. Findings demonstrate that while student feedback is…

Sensori-Motor Learning with Movement Sonification: Perspectives from Recent Interdisciplinary Studies.

PubMed

Bevilacqua, Frédéric; Boyer, Eric O; Françoise, Jules; Houix, Olivier; Susini, Patrick; Roby-Brami, Agnès; Hanneton, Sylvain

2016-01-01

This article reports on an interdisciplinary research project on movement sonification for sensori-motor learning. First, we describe different research fields which have contributed to movement sonification, from music technology including gesture-controlled sound synthesis, sonic interaction design, to research on sensori-motor learning with auditory-feedback. In particular, we propose to distinguish between sound-oriented tasks and movement-oriented tasks in experiments involving interactive sound feedback. We describe several research questions and recently published results on movement control, learning and perception. In particular, we studied the effect of the auditory feedback on movements considering several cases: from experiments on pointing and visuo-motor tracking to more complex tasks where interactive sound feedback can guide movements, or cases of sensory substitution where the auditory feedback can inform on object shapes. We also developed specific methodologies and technologies for designing the sonic feedback and movement sonification. We conclude with a discussion on key future research challenges in sensori-motor learning with movement sonification. We also point out toward promising applications such as rehabilitation, sport training or product design.

Numerical methods for large eddy simulation of acoustic combustion instabilities

NASA Astrophysics Data System (ADS)

Wall, Clifton T.

Acoustic combustion instabilities occur when interaction between the combustion process and acoustic modes in a combustor results in periodic oscillations in pressure, velocity, and heat release. If sufficiently large in amplitude, these instabilities can cause operational difficulties or the failure of combustor hardware. In many situations, the dominant instability is the result of the interaction between a low frequency acoustic mode of the combustor and the large scale hydrodynamics. Large eddy simulation (LES), therefore, is a promising tool for the prediction of these instabilities, since both the low frequency acoustic modes and the large scale hydrodynamics are well resolved in LES. Problems with the tractability of such simulations arise, however, due to the difficulty of solving the compressible Navier-Stokes equations efficiently at low Mach number and due to the large number of acoustic periods that are often required for such instabilities to reach limit cycles. An implicit numerical method for the solution of the compressible Navier-Stokes equations has been developed which avoids the acoustic CFL restriction, allowing for significant efficiency gains at low Mach number, while still resolving the low frequency acoustic modes of interest. In the limit of a uniform grid the numerical method causes no artificial damping of acoustic waves. New, non-reflecting boundary conditions have also been developed for use with the characteristic-based approach of Poinsot and Lele (1992). The new boundary conditions are implemented in a manner which allows for significant reduction of the computational domain of an LES by eliminating the need to perform LES in regions where one-dimensional acoustics significantly affect the instability but details of the hydrodynamics do not. These new numerical techniques have been demonstrated in an LES of an experimental combustor. The new techniques are shown to be an efficient means of performing LES of acoustic combustion instabilities and are shown to accurately predict the occurrence and frequency of the dominant mode of the instability observed in the experiment.

Large-Eddy / Reynolds-Averaged Navier-Stokes Simulations of a Dual-Mode Scramjet Combustor

NASA Technical Reports Server (NTRS)

Fulton, Jesse A.; Edwards, Jack R.; Hassan, Hassan A.; Rockwell, Robert; Goyne, Christopher; McDaniel, James; Smith, Chad; Cutler, Andrew; Johansen, Craig; Danehy, Paul M.;

Spatial large-eddy simulations of contrail formation in the wake of an airliner

NASA Astrophysics Data System (ADS)

Paoli, R.

2015-12-01

Contrails and contrail-cirrus are the most uncertain contributors to aviation radiative forcing. In order to reduce this uncertainty one needs to gain more knowledge on the physicochemical processes occurring in the aircraft plume, which eventually lead to the transformation of contrails into cirrus. To that end, the accurate prediction of the number of activated particles and their spatial and size distributions at the end of the jet regime may be helpful to initialize simulations in the following vortex regime. We present the results from spatial large-eddy simulations (LES) of contrail formation in the near-field wake of a generic (but full-scale) airliner that is representative of those used in long-haul flights in current fleets. The flow around the aircraft has been computed using a RANS code taking into account the full geometry that include the engines and the aerodynamic set-up for cruise conditions. The data have been reconstructed at a plane closely behind the trailing edge of the wing and used as inflow boundary conditions for the LES. We employ fully compressible 3D LES coupled to Lagrangian microphysical module that tracks parcels of ice particles individually. The ice microphysical model is simple yet it contains the basic thermodynamic ingredients to model soot activation and water vapor deposition. Compared to one-dimensional models or even RANS, LES allow for more accurate predictions of the mixing between exhaust and ambient air. Hence, the number of activated particles and the ice growth rate can be also determined with higher accuracy. This is particularly crucial for particles located at the edge of the jet that experience large gradients of temperature and humidity. The results of the fully coupled LES (where the gas phase and the particles are solved together) are compared to offline simulations where the ice microphysics model is run using thermodynamic data from pre-calculated particle trajectories extracted from inert LES (where ice microphysics has been switched off).

Feedback produces divergence from prospect theory in descriptive choice.

PubMed

Jessup, Ryan K; Bishara, Anthony J; Busemeyer, Jerome R

2008-10-01

A recent study demonstrated that individuals making experience-based choices underweight small probabilities, in contrast to the overweighting observed in a typical descriptive paradigm. We tested whether trial-by-trial feedback in a repeated descriptive paradigm would engender choices more correspondent with experiential or descriptive paradigms. The results of a repeated gambling task indicated that individuals receiving feedback underweighted small probabilities, relative to their no-feedback counterparts. These results implicate feedback as a critical component during the decision-making process, even in the presence of fully specified descriptive information. A model comparison at the individual-subject level suggested that feedback drove individuals' decision weights toward objective probability weighting.

Experience dans une classe d'immersion francaise aux Milles-Iles (An Experience in a French Immersion Class in Mille-Iles)

ERIC Educational Resources Information Center

Pariseau, Cecile

1978-01-01

A description of an immersion program for 6-year-old anglophone children modeled on "les classes d'accueil" for immigrant children. The program of intensive instruction in oral and written French is outlined. This school district has found this type of immersion superior to the usual kind. (The text is in French.) (AMH)

The foreign language effect on the self-serving bias: A field experiment in the high school classroom.

PubMed

van Hugten, Joeri; van Witteloostuijn, Arjen

2018-01-01

The rise of bilingual education triggers an important question: which language is preferred for a particular school activity? Our field experiment (n = 120) shows that students (aged 13-15) who process feedback in non-native English have greater self-serving bias than students who process feedback in their native Dutch. By contrast, literature on the foreign-language emotionality effect suggests a weaker self-serving bias in the non-native language, so our result adds nuance to that literature. The result is important to schools as it suggests that teachers may be able to reduce students' defensiveness and demotivation by communicating negative feedback in the native language, and teachers may be able to increase students' confidence and motivation by communicating positive feedback in the foreign language.

Validation of a Statistical Methodology for Extracting Vegetation Feedbacks: Focus on North African Ecosystems in the Community Earth System Model

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

Yu, Yan; Notaro, Michael; Wang, Fuyao

Generalized equilibrium feedback assessment (GEFA) is a potentially valuable multivariate statistical tool for extracting vegetation feedbacks to the atmosphere in either observations or coupled Earth system models. The reliability of GEFA at capturing the terrestrial impacts on regional climate is demonstrated in this paper using the National Center for Atmospheric Research Community Earth System Model (CESM), with focus on North Africa. The feedback is assessed statistically by applying GEFA to output from a fully coupled control run. To reduce the sampling error caused by short data records, the traditional or full GEFA is refined through stepwise GEFA by dropping unimportantmore » forcings. Two ensembles of dynamical experiments are developed for the Sahel or West African monsoon region against which GEFA-based vegetation feedbacks are evaluated. In these dynamical experiments, regional leaf area index (LAI) is modified either alone or in conjunction with soil moisture, with the latter runs motivated by strong regional soil moisture–LAI coupling. Stepwise GEFA boasts higher consistency between statistically and dynamically assessed atmospheric responses to land surface anomalies than full GEFA, especially with short data records. GEFA-based atmospheric responses are more consistent with the coupled soil moisture–LAI experiments, indicating that GEFA is assessing the combined impacts of coupled vegetation and soil moisture. Finally, both the statistical and dynamical assessments reveal a negative vegetation–rainfall feedback in the Sahel associated with an atmospheric stability mechanism in CESM versus a weaker positive feedback in the West African monsoon region associated with a moisture recycling mechanism in CESM.« less

Validation of a Statistical Methodology for Extracting Vegetation Feedbacks: Focus on North African Ecosystems in the Community Earth System Model

DOE PAGES

Yu, Yan; Notaro, Michael; Wang, Fuyao; ...

2018-02-05

Generalized equilibrium feedback assessment (GEFA) is a potentially valuable multivariate statistical tool for extracting vegetation feedbacks to the atmosphere in either observations or coupled Earth system models. The reliability of GEFA at capturing the terrestrial impacts on regional climate is demonstrated in this paper using the National Center for Atmospheric Research Community Earth System Model (CESM), with focus on North Africa. The feedback is assessed statistically by applying GEFA to output from a fully coupled control run. To reduce the sampling error caused by short data records, the traditional or full GEFA is refined through stepwise GEFA by dropping unimportantmore » forcings. Two ensembles of dynamical experiments are developed for the Sahel or West African monsoon region against which GEFA-based vegetation feedbacks are evaluated. In these dynamical experiments, regional leaf area index (LAI) is modified either alone or in conjunction with soil moisture, with the latter runs motivated by strong regional soil moisture–LAI coupling. Stepwise GEFA boasts higher consistency between statistically and dynamically assessed atmospheric responses to land surface anomalies than full GEFA, especially with short data records. GEFA-based atmospheric responses are more consistent with the coupled soil moisture–LAI experiments, indicating that GEFA is assessing the combined impacts of coupled vegetation and soil moisture. Finally, both the statistical and dynamical assessments reveal a negative vegetation–rainfall feedback in the Sahel associated with an atmospheric stability mechanism in CESM versus a weaker positive feedback in the West African monsoon region associated with a moisture recycling mechanism in CESM.« less

Time-accurate simulations of a shear layer forced at a single frequency

NASA Technical Reports Server (NTRS)

Claus, R. W.; Huang, P. G.; Macinnes, J. M.

1988-01-01

Calculations are presented for the forced shear layer studied experimentally by Oster and Wygnanski, and Weisbrot. Two different computational approaches are examined: Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES). The DNS approach solves the full three dimensional Navier-Stokes equations for a temporally evolving mixing layer, while the LES approach solves the two dimensional Navier-Stokes equations with a subgrid scale turbulence model. While the comparison between these calculations and experimental data was hampered by a lack of information on the inflow boundary conditions, the calculations are shown to qualitatively agree with several aspects of the experiment. The sensitivity of these calculations to factors such as mesh refinement and Reynolds number is illustrated.

Do Student Evaluations of University Reflect Inaccurate Beliefs or Actual Experience? A Relative Rank Model

PubMed Central

Brown, Gordon D A; Wood, Alex M; Ogden, Ruth S; Maltby, John

2015-01-01

It was shown that student satisfaction ratings are influenced by context in ways that have important theoretical and practical implications. Using questions from the UK's National Student Survey, the study examined whether and how students' expressed satisfaction with issues such as feedback promptness and instructor enthusiasm depends on the context of comparison (such as possibly inaccurate beliefs about the feedback promptness or enthusiasm experienced at other universities) that is evoked. Experiment 1 found strong effects of experimentally provided comparison context—for example, satisfaction with a given feedback time depended on the time's relative position within a context. Experiment 2 used a novel distribution-elicitation methodology to determine the prior beliefs of individual students about what happens in universities other than their own. It found that these beliefs vary widely and that students' satisfaction was predicted by how they believed their experience ranked within the distribution of others' experiences. A third study found that relative judgement principles also predicted students' intention to complain. An extended model was developed to show that purely rank-based principles of judgement can account for findings previously attributed to range effects. It was concluded that satisfaction ratings and quality of provision are different quantities, particularly when the implicit context of comparison includes beliefs about provision at other universities. Quality and satisfaction should be assessed separately, with objective measures (such as actual times to feedback), rather than subjective ratings (such as satisfaction with feedback promptness), being used to measure quality wherever practicable. © 2014 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd. PMID:25620847

Knowledge of Previous Tasks: Task Similarity Influences Bias in Task Duration Predictions

PubMed Central

Thomas, Kevin E.; König, Cornelius J.

2018-01-01

Bias in predictions of task duration has been attributed to misremembering previous task duration and using previous task duration as a basis for predictions. This research sought to further examine how previous task information affects prediction bias by manipulating task similarity and assessing the role of previous task duration feedback. Task similarity was examined through participants performing two tasks 1 week apart that were the same or different. Duration feedback was provided to all participants (Experiment 1), its recall was manipulated (Experiment 2), and its provision was manipulated (Experiment 3). In all experiments, task similarity influenced bias on the second task, with predictions being less biased when the first task was the same task. However, duration feedback did not influence bias. The findings highlight the pivotal role of knowledge about previous tasks in task duration prediction and are discussed in relation to the theoretical accounts of task duration prediction bias. PMID:29881362

Facilitated patient experience feedback can improve nursing care: a pilot study for a phase III cluster randomised controlled trial

PubMed Central

2013-01-01

Background England’s extensive NHS patient survey programme has not fulfilled government promises of widespread improvements in patients’ experiences, and media reports of poor nursing care in NHS hospitals are increasingly common. Impediments to the surveys’ impact on the quality of nursing care may include: the fact that they are not ward-specific, so nurses claim “that doesn’t happen on my ward”; nurses’ scepticism about the relevance of patient feedback to their practice; and lack of prompt communication of results. The surveys’ impact could be increased by: conducting ward-specific surveys; returning results to ward staff more quickly; including patients’ written comments in reports; and offering nurses an opportunity to discuss the feedback. Very few randomised trials have been conducted to test the effectiveness of patient feedback on quality improvement and there have been few, if any, published trials of ward-specific patient surveys. Methods Over two years, postal surveys of recent inpatients were conducted at four-monthly intervals in 18 wards in two NHS Trusts in England. Wards were randomly allocated to Basic Feedback (ward-specific printed patient survey results including patients’ written comments sent to nurses by letter); Feedback Plus (in addition to printed results, ward meetings to discuss results and plan improvements) or Control (no active feedback of survey results). Patient survey responses to questions about nursing care were used to compute wards’ average Nursing Care Scores at each interval. Nurses’ reactions to the patient feedback were recorded. Results Conducting ward-level surveys and delivering ward-specific results was feasible. Ward meetings were effective for engaging nurses and challenging scepticism and patients’ written comments stimulated interest. 4,236 (47%) patients returned questionnaires. Nursing Care Scores improved more for Feedback Plus than Basic Feedback or Control (difference between Control and Feedback Plus = 8.28 ± 7.2 (p = 0.02)). Conclusions This study provides preliminary evidence that facilitated patient feedback can improve patients’ experiences such that a full trial is justified. These findings suggest that merely informing nurses of patient survey results in writing does not stimulate improvements, even if results are disaggregated by ward, but the addition of ward meetings had an important and significant impact. PMID:23826970

Etude spectroscopique des collisions moleculaires (hydrogene-azote et hydrogene-oxygene) a des energies de quelques MeV

NASA Astrophysics Data System (ADS)

Plante, Jacinthe

1998-09-01

Les resultats presentes ici proviennent d'une etude systematique portant sur les collisions a vitesse constante, entre les projectiles d'hydrogene (H+, H2+ et H3+ a 1 MeV/nucleon) et deux cibles gazeuses (N2 et O2), soumises a differentes pressions. Les collisions sont analysees a l'aide des spectres d'emission (de 400 A a 6650 A) et des graphiques intensite/pression. Les spectres ont revele la presence des raies d'azote atomique, d'azote moleculaire, d'oxygene atomique, d'oxygene moleculaire et d'hydrogene atomique. Les raies d'hydrogene sont observees seulement avec les projectiles H2+ et H3+. Donc les processus responsables de la formation de ces raies sont des mecanismes de fragmentation des projectiles. Pour conclure, il existe une difference notable entre les projectiles et les differentes pressions. Les raies d'azote et d'oxygene augmentent selon la pression et les raies d'hydrogene atomique presentent une relation non lineaire avec la pression.

La fibroscopie digestive haute chez 2795 patients au centre hospitalier universitaire-campus de Lomé: les particularités selon le sexe

PubMed Central

Lawson-Ananissoh, Laté Mawuli; Bouglouga, Oumboma; Bagny, Aklesso; Kaaga, Laconi; Redah, Datouda

2014-01-01

Introduction Notre étude consistera à rapporter les indications et les lésions objectivées à la fibroscopie digestive haute et relever les particularités selon le sexe. Méthodes Étude rétrospective, descriptive sur des résultats de compte-rendu de la fibroscopie digestive haute menée en unité d'endoscopie digestive du service d'hépato-gastro-entérologie du CHU Campus de Lomé du 15 Mai 2009 au 31 Décembre 2013. Résultats La fibroscopie digestive haute a été réalisée chez 2795 patients dont 1188 hommes et 1607 femmes. L’âge moyen était de 40,65 ans (Extrêmes: 5 et 93 ans). La fibroscopie digestive haute était normale chez les femmes que chez les hommes avec une différence statistiquement significative (p = 0,000). Les principales indications étaient: les épigastralgies chez les femmes (p = 0,000); les hémorragies digestives hautes (p = 0,000) et l'hypertension portale (p = 0,000) chez les hommes; 3485 lésions pathologiques ont été observées. La pathologie inflammatoire prédominait (56,3%), la pathologie ulcéreuse (13,89%), la pathologie tumorale (2,01%). Les varices et la candidose œsophagiennes étaient significativement notées chez les hommes. Les ulcérations gastriques (p = 0,000), le reflux biliaire duodéno-gastrique (p = 0,017) étaient plus retrouvés chez les femmes et la gastropathie hypertensive beaucoup plus chez les hommes (p = 0,000). Que les lésions duodénales soient inflammatoires ou ulcéreuses associées ou non à une sténose bulbaire, elles étaient plus fréquentes chez les hommes. Conclusion De manière générale, il y avait une prédominance des lésions inflammatoires chez les femmes, les lésions tumorales et ulcéreuses chez les hommes PMID:25852805

Experiments with explicit filtering for LES using a finite-difference method

NASA Technical Reports Server (NTRS)

Lund, T. S.; Kaltenbach, H. J.

1995-01-01

The equations for large-eddy simulation (LES) are derived formally by applying a spatial filter to the Navier-Stokes equations. The filter width as well as the details of the filter shape are free parameters in LES, and these can be used both to control the effective resolution of the simulation and to establish the relative importance of different portions of the resolved spectrum. An analogous, but less well justified, approach to filtering is more or less universally used in conjunction with LES using finite-difference methods. In this approach, the finite support provided by the computational mesh as well as the wavenumber-dependent truncation errors associated with the finite-difference operators are assumed to define the filter operation. This approach has the advantage that it is also 'automatic' in the sense that no explicit filtering: operations need to be performed. While it is certainly convenient to avoid the explicit filtering operation, there are some practical considerations associated with finite-difference methods that favor the use of an explicit filter. Foremost among these considerations is the issue of truncation error. All finite-difference approximations have an associated truncation error that increases with increasing wavenumber. These errors can be quite severe for the smallest resolved scales, and these errors will interfere with the dynamics of the small eddies if no corrective action is taken. Years of experience at CTR with a second-order finite-difference scheme for high Reynolds number LES has repeatedly indicated that truncation errors must be minimized in order to obtain acceptable simulation results. While the potential advantages of explicit filtering are rather clear, there is a significant cost associated with its implementation. In particular, explicit filtering reduces the effective resolution of the simulation compared with that afforded by the mesh. The resolution requirements for LES are usually set by the need to capture most of the energy-containing eddies, and if explicit filtering is used, the mesh must be enlarged so that these motions are passed by the filter. Given the high cost of explicit filtering, the following interesting question arises. Since the mesh must be expanded in order to perform the explicit filter, might it be better to take advantage of the increased resolution and simply perform an unfiltered simulation on the larger mesh? The cost of the two approaches is roughly the same, but the philosophy is rather different. In the filtered simulation, resolution is sacrificed in order to minimize the various forms of numerical error. In the unfiltered simulation, the errors are left intact, but they are concentrated at very small scales that could be dynamically unimportant from a LES perspective. Very little is known about this tradeoff and the objective of this work is to study this relationship in high Reynolds number channel flow simulations using a second-order finite-difference method.

Learning from the Implementers in a Design Experiment

ERIC Educational Resources Information Center

Toh, Tin Lam; Dindyal, Jaguthsing; Tay, Eng Guan

2013-01-01

In a design experiment, the feedback from the teacher-implementer is crucial to the success of the innovation simply because the teacher is finally the one that brings the innovation to life in front of the students. We describe in this paper the feedback made by the teacher-implementer after teaching one cycle of the problem solving module in a…

Are Success and Failure Experiences Equally Motivational? An Investigation of Regulatory Focus and Feedback

ERIC Educational Resources Information Center

Shu, Tse-Mei; Lam, Shui-fong

2011-01-01

The present study extended regulatory focus theory (Idson & Higgins, 2000) to an educational setting and attempted to identify individuals with high motivation after both success and failure feedback. College students in Hong Kong (N = 180) participated in an experiment with a 2 promotion focus (high vs. low) x 2 prevention focus (high vs.…

Effects of Achievement Goals on Challenge Seeking and Feedback Processing: Behavioral and fMRI Evidence

PubMed Central

Lee, Woogul; Kim, Sung-il

2014-01-01

We conducted behavioral and functional magnetic resonance imaging (fMRI) research to investigate the effects of two types of achievement goals—mastery goals and performance-approach goals— on challenge seeking and feedback processing. The results of the behavioral experiment indicated that mastery goals were associated with a tendency to seek challenge, both before and after experiencing difficulty during task performance, whereas performance-approach goals were related to a tendency to avoid challenge after encountering difficulty during task performance. The fMRI experiment uncovered a significant decrease in ventral striatal activity when participants received negative feedback for any task type and both forms of achievement goals. During the processing of negative feedback for the rule-finding task, performance-approach-oriented participants showed a substantial reduction in activity in the dorsolateral prefrontal cortex (DLPFC) and the frontopolar cortex, whereas mastery-oriented participants showed little change. These results suggest that performance-approach-oriented participants are less likely to either recruit control processes in response to negative feedback or focus on task-relevant information provided alongside the negative feedback. In contrast, mastery-oriented participants are more likely to modulate aversive valuations to negative feedback and focus on the constructive elements of feedback in order to attain their task goals. We conclude that performance-approach goals lead to a reluctant stance towards difficulty, while mastery goals encourage a proactive stance. PMID:25251396

An Exploration of Asynchronous and Synchronous Feedback Modes in EFL Writing

ERIC Educational Resources Information Center

Shang, Hui-Fang

2017-01-01

In the English as a foreign language (EFL) writing context, most of the research studies on the feedback process are conducted in a face-to-face context and few research studies have been conducted to investigate what actually happens in online feedback conditions. Thus, this study aimed to compare 44 EFL university students' experience of…

Category Rating Is Based on Prototypes and Not Instances: Evidence from Feedback-Dependent Context Effects

ERIC Educational Resources Information Center

Petrov, Alexander A.

2011-01-01

Context effects in category rating on a 7-point scale are shown to reverse direction depending on feedback. Context (skewed stimulus frequencies) was manipulated between and feedback within subjects in two experiments. The diverging predictions of prototype- and exemplar-based scaling theories were tested using two representative models: ANCHOR…

Attending to Student Voice: The Impact of Descriptive Feedback on Learning and Teaching

ERIC Educational Resources Information Center

Rodgers, Carol R.

2006-01-01

This article explores the central role that description of experience, on the part of both teacher and students, plays in reflective practice. In particular, it highlights the power of students' description of their own learning as revealed to teachers in dialogue, a process I call "descriptive feedback." Descriptive feedback is neither…

Learning Intercultural Communication Skills with Virtual Humans: Feedback and Fidelity

ERIC Educational Resources Information Center

Lane, H. Chad; Hays, Matthew Jensen; Core, Mark G.; Auerbach, Daniel

2013-01-01

In the context of practicing intercultural communication skills, we investigated the role of fidelity in a game-based, virtual learning environment as well as the role of feedback delivered by an intelligent tutoring system. In 2 experiments, we compared variations on the game interface, use of the tutoring system, and the form of the feedback.…

Enabling Microblogging-Based Peer Feedback in Face-to-Face Classrooms

ERIC Educational Resources Information Center

Luo, Tian

2016-01-01

The purpose of this paper is to understand student interaction and learning in microblogging-based peer feedback sessions. The researcher examined through a case study how students interacted and provided peer feedback for each other when Twitter was enabled as a backchannel; students were also asked to report how they perceived their experience.…

Toward Making the Invisible Visible Using a Scale: Prospective Teachers' Thoughts and Affective Reactions to Feedback

ERIC Educational Resources Information Center

Akkuzu, Nalan; Uyulgan, Melis Arzu

2014-01-01

This paper presents the development and initial validation of a feedback scale which measures the thoughts and affective reactions of prospective teachers concerning feedback on their teaching experiences. To reach this goal, data from 512 prospective teachers were used to test the internal consistency, exploratory and confirmative factor…

The Effects of Field Experience on Delivery of Feedback

ERIC Educational Resources Information Center

Ramos, Adolfo R.; Esslinger, Kerry; Pyle, Elizabeth

2015-01-01

The purpose of this study was to examine pre-service teachers' (PTs) ability to deliver feedback, which has been used as a process variable in identifying teacher-effectiveness and an established NASPE standard for beginning teachers. These questions guided the study: 1. Will overall feedback interactions delivered by PTs reach 45 per video? 2.…

User Feedback Procedures; Part III of Scientific Report No. ISR-18, Information Storage and Retrieval...

ERIC Educational Resources Information Center

Cornell Univ., Ithaca, NY. Dept. of Computer Science.

Part Three of this five part report on Salton's Magical Automatic Retriever of Texts (SMART) project contains four papers. The first: "Variations on the Query Splitting Technique with Relevance Feedback" by T. P. Baker discusses some experiments in relevance feedback performed with variations on the technique of query splitting. The…

Enhancing the Assessment Experience: Improving Student Perceptions, Engagement and Understanding Using Online Video Feedback

ERIC Educational Resources Information Center

West, John; Turner, Will

2016-01-01

Individualised video screencasts with accompanying narration were used to provide assessment feedback to a large number (n = 299) of first-year Bachelor of Education students at Edith Cowan University in Western Australia. An anonymous online survey revealed that nearly three times as many respondents (61%) preferred video feedback to written…

Effects of Real-Time Visual Feedback on Pre-Service Teachers' Singing

ERIC Educational Resources Information Center

Leong, S.; Cheng, L.

2014-01-01

This pilot study focuses on the use real-time visual feedback technology (VFT) in vocal training. The empirical research has two aims: to ascertain the effectiveness of the real-time visual feedback software "Sing & See" in the vocal training of pre-service music teachers and the teachers' perspective on their experience with…

Feedback Both Helps and Hinders Learning: The Causal Role of Prior Knowledge

ERIC Educational Resources Information Center

Fyfe, Emily R.; Rittle-Johnson, Bethany

2016-01-01

Feedback can be a powerful learning tool, but its effects vary widely. Research has suggested that learners' prior knowledge may moderate the effects of feedback; however, no causal link has been established. In Experiment 1, we randomly assigned elementary school children (N = 108) to a condition based on a crossing of 2 factors: induced strategy…

The Benefits of Computer-Generated Feedback for Mathematics Problem Solving

ERIC Educational Resources Information Center

Fyfe, Emily R.; Rittle-Johnson, Bethany

2016-01-01

The goal of the current research was to better understand when and why feedback has positive effects on learning and to identify features of feedback that may improve its efficacy. In a randomized experiment, second-grade children (N = 75) received instruction on a correct problem-solving strategy and then solved a set of relevant problems.…

The Role and Functionality of Emotions in Feedback at University: A Qualitative Study

ERIC Educational Resources Information Center

Rowe, Anna D.; Fitness, Julie; Wood, Leigh N.

2014-01-01

This paper reports on a qualitative study exploring the role and functionality of emotions in feedback. In-depth interview data from students and lecturers at an Australian university are analysed using cognitive appraisal and prototype theory. Results suggest that students experience a range of positive and negative emotions in feedback contexts…

Design of the RWM Feedback Control System for NSTX

NASA Astrophysics Data System (ADS)

Bialek, James; Sabbagh, Steven; Paoletti, Franco

2002-11-01

The National Spherical Torus Experiment ( NSTX ) has been designed to investigate the physics of global mode stabilization at low aspect ratio. Present experiments are now probing performance limits determined by machine configuration and passive stabilization. For example, the ideal no-wall normalized beta limit has already been exceeded by greater than 20stabilized by a nearby perfectly conducting wall are observed to grow at a rate determined by nearby resistive structure. Sustained performance improvements may be obtained by using active feedback to suppress such long wavelength pressure driven instabilities, known as resistive wall modes (RWM). We report on the performance of several design options for an NSTX - RWM feedback control system. The VALEN feedback analysis code has been used to evaluate the performance of these configurations. We explicitly model the vacuum vessel, center stack casing, the 48 copper passive plates, their mounts, active feedback coils and sensor arrays. The highest performance system has both control coils and sensors inside the vacuum vessel. In this case it is possible to reach 94beta limit.

Probability matching in risky choice: the interplay of feedback and strategy availability.

PubMed

Newell, Ben R; Koehler, Derek J; James, Greta; Rakow, Tim; van Ravenzwaaij, Don

2013-04-01

Probability matching in sequential decision making is a striking violation of rational choice that has been observed in hundreds of experiments. Recent studies have demonstrated that matching persists even in described tasks in which all the information required for identifying a superior alternative strategy-maximizing-is present before the first choice is made. These studies have also indicated that maximizing increases when (1) the asymmetry in the availability of matching and maximizing strategies is reduced and (2) normatively irrelevant outcome feedback is provided. In the two experiments reported here, we examined the joint influences of these factors, revealing that strategy availability and outcome feedback operate on different time courses. Both behavioral and modeling results showed that while availability of the maximizing strategy increases the choice of maximizing early during the task, feedback appears to act more slowly to erode misconceptions about the task and to reinforce optimal responding. The results illuminate the interplay between "top-down" identification of choice strategies and "bottom-up" discovery of those strategies via feedback.

Feedback: an essential element of student learning in clinical practice.

PubMed

Clynes, Mary P; Raftery, Sara E C

2008-11-01

Clinical practice is an essential component of the nursing curriculum. In order for the student to benefit fully from the experience regular performance feedback is required. Feedback should provide the student with information on current practice and offer practical advice for improved performance. The importance of feedback is widely acknowledged however it appears that there is inconsistency in its provision to students. The benefits of feedback include increased student confidence, motivation and self-esteem as well as improved clinical practice. Benefits such as enhanced interpersonal skills and a sense of personal satisfaction also accrue to the supervisor. Barriers to the feedback process are identified as inadequate supervisor training and education, unfavourable ward learning environment and insufficient time spent with students. In addition to the appropriate preparation of the supervisor effective feedback includes an appreciation of the steps of the feedback process, an understanding of the student response to feedback and effective communication skills.

Effectiveness of In-Home Feedback Devices in Conjunction with Energy Use Information on Residential Energy Consumption

NASA Astrophysics Data System (ADS)

Rungta, Shaily

Residential energy consumption accounts for 22% of the total energy use in the United States. The consumer's perception of energy usage and conservation are very inaccurate which is leading to growing number of individuals who try to seek out ways to use energy more wisely. Hence behavioral change in consumers with respect to energy use, by providing energy use feedback may be important in reducing home energy consumption. Real-time energy information feedback delivered via technology along with feedback interventions has been reported to produce up to 20 percent declines in residential energy consumption through past research and pilot studies. There are, however, large differences in the estimates of the effect of these different types of feedback on energy use. As part of the Energize Phoenix Program, (a U.S. Department of Energy funded program), a Dashboard Study was conducted by the Arizona State University to estimate the impact of real-time, home-energy displays in conjunction with other feedback interventions on the residential rate of energy consumption in Phoenix, while also creating awareness and encouragement to households to reduce energy consumption. The research evaluates the effectiveness of these feedback initiatives. In the following six months of field experiment, a selected number of low-income multi-family apartments in Phoenix, were divided in three groups of feedback interventions, where one group received residential energy use related education and information, the second group received the same education as well as was equipped with the in-home feedback device and the third was given the same education, the feedback device and added budgeting information. Results of the experiment at the end of the six months did not lend a consistent support to the results from literature and past pilot studies. The data revealed a statistically insignificant reduction in energy consumption for the experiment group overall and inconsistent results for individual households when compared to a randomly selected control sample. However, as per the participant survey results, the study proved effective to foster awareness among participating residents of their own patterns of residential electricity consumption and understanding of residential energy use related savings.

Commerce de detail de l'essence automobile: Modelisation de l'impact a court terme des facteurs endogenes et exogenes sur les ventes d'essence dans les stations-service a Montreal

NASA Astrophysics Data System (ADS)

Nguimbus, Raphael

La determination de l'impact des facteurs sous controle et hors controle qui influencent les volumes de vente des magasins de detail qui vendent des produits homogenes et fortement substituables constitue le coeur de cette these. Il s'agit d'estimer un ensemble de coefficients stables et asymtotiquement efficaces non correles avec les effets specifiques aleatoires des sites d'essence dans le marche de Montreal (Quebec, Canada) durant is periode 1993--1997. Le modele econometrique qui est ainsi specifie et teste, isole un ensemble de quatre variables dont le prix de detail affiche dans un site d'essence ordinaire, la capacite de service du site pendant les heures de pointe, les heures de service et le nombre de sites concurrents au voisinage du site dans un rayon de deux kilometres. Ces quatre facteurs influencent les ventes d'essence dans les stations-service. Les donnees en panel avec les methodes d'estimation robustes (estimateur a distance minimale) sont utilisees pour estimer les parametres du modele de vente. Nous partons avec l'hypothese generale selon laquelle il se developpe une force d'attraction qui attire les clients automobilistes dans chaque site, et qui lui permet de realiser les ventes. Cette capacite d'attraction varie d'un site a un autre et cela est du a la combinaison de l'effort marketing et de l'environnement concurrentiel autour du site. Les notions de voisinage et de concurrence spatiale expliquent les comportements des decideurs qui gerent les sites. Le but de cette these est de developper un outil d'aide a la decision (modele analytique) pour permettre aux gestionnaires des chaines de stations-service d'affecter efficacement les ressources commerciales dans ies points de vente.

Effects of mediated social touch on affective experiences and trust.

PubMed

Erk, Stefanie M; Toet, Alexander; Van Erp, Jan B F

2015-01-01

This study investigated whether communication via mediated hand pressure during a remotely shared experience (watching an amusing video) can (1) enhance recovery from sadness, (2) enhance the affective quality of the experience, and (3) increase trust towards the communication partner. Thereto participants first watched a sad movie clip to elicit sadness, followed by a funny one to stimulate recovery from sadness. While watching the funny clip they signaled a hypothetical fellow participant every time they felt amused. In the experimental condition the participants responded by pressing a hand-held two-way mediated touch device (a Frebble), which also provided haptic feedback via simulated hand squeezes. In the control condition they responded by pressing a button and they received abstract visual feedback. Objective (heart rate, galvanic skin conductance, number and duration of joystick or Frebble presses) and subjective (questionnaires) data were collected to assess the emotional reactions of the participants. The subjective measurements confirmed that the sad movie successfully induced sadness while the funny movie indeed evoked more positive feelings. Although their ranking agreed with the subjective measurements, the physiological measurements confirmed this conclusion only for the funny movie. The results show that recovery from movie induced sadness, the affective experience of the amusing movie, and trust towards the communication partner did not differ between both experimental conditions. Hence, feedback via mediated hand touching did not enhance either of these factors compared to visual feedback. Further analysis of the data showed that participants scoring low on Extraversion (i.e., persons that are more introvert) or low on Touch Receptivity (i.e., persons who do not like to be touched by others) felt better understood by their communication partner when receiving mediated touch feedback instead of visual feedback, while the opposite was found for participants scoring high on these factors. The implications of these results for further research are discussed, and some suggestions for follow-up experiments are presented.

Effects of mediated social touch on affective experiences and trust

PubMed Central

Erk, Stefanie M.; Van Erp, Jan B.F.

2015-01-01

This study investigated whether communication via mediated hand pressure during a remotely shared experience (watching an amusing video) can (1) enhance recovery from sadness, (2) enhance the affective quality of the experience, and (3) increase trust towards the communication partner. Thereto participants first watched a sad movie clip to elicit sadness, followed by a funny one to stimulate recovery from sadness. While watching the funny clip they signaled a hypothetical fellow participant every time they felt amused. In the experimental condition the participants responded by pressing a hand-held two-way mediated touch device (a Frebble), which also provided haptic feedback via simulated hand squeezes. In the control condition they responded by pressing a button and they received abstract visual feedback. Objective (heart rate, galvanic skin conductance, number and duration of joystick or Frebble presses) and subjective (questionnaires) data were collected to assess the emotional reactions of the participants. The subjective measurements confirmed that the sad movie successfully induced sadness while the funny movie indeed evoked more positive feelings. Although their ranking agreed with the subjective measurements, the physiological measurements confirmed this conclusion only for the funny movie. The results show that recovery from movie induced sadness, the affective experience of the amusing movie, and trust towards the communication partner did not differ between both experimental conditions. Hence, feedback via mediated hand touching did not enhance either of these factors compared to visual feedback. Further analysis of the data showed that participants scoring low on Extraversion (i.e., persons that are more introvert) or low on Touch Receptivity (i.e., persons who do not like to be touched by others) felt better understood by their communication partner when receiving mediated touch feedback instead of visual feedback, while the opposite was found for participants scoring high on these factors. The implications of these results for further research are discussed, and some suggestions for follow-up experiments are presented. PMID:26557429

LES on Plume Dispersion in the Convective Boundary Layer Capped by a Temperature Inversion

NASA Astrophysics Data System (ADS)

Nakayama, Hiromasa; Tamura, Tetsuro; Abe, Satoshi

Large-eddy simulation (LES) is applied to the problem of plume dispersion in the spatially-developing convective boundary layer (CBL) capped by a temperature inversion. In order to generate inflow turbulence with buoyant forcing, we first, simulate the neutral boundary layer flow (NBL) in the driver region using Lund's method. At the same time, the temperature profile possessing the inversion part is imposed at the entrance of the driver region and the temperature field is calculated as a passive scalar. Next, the buoyancy effect is introduced into the flow field in the main region. We evaluate the applicability of the LES model for atmospheric dispersion in the CBL flow and compare the characteristics of plume dispersion in the CBL flow with those in the neutral boundary layer. The Richardson number based on the temperature increment across the inversion obtained by the present LES model is 22.4 and the capping effect of the temperature inversion can be captured qualitatively in the upper portion of the CBL. Characteristics of flow and temperature fields in the main portion of CBL flow are similar to those of previous experiments[1],[2] and observations[3]. Concerning dispersion behavior, we also find that mean concentrations decrease immediately above the inversion height and the peak values of r.m.s concentrations are located near the inversion height at larger distances from the point source.

Multiplicative Process in Turbulent Velocity Statistics: A Simplified Analysis

NASA Astrophysics Data System (ADS)

Chillà, F.; Peinke, J.; Castaing, B.

1996-04-01

A lot of models in turbulence links the energy cascade process and intermittency, the characteristic of which being the shape evolution of the probability density functions (pdf) for longitudinal velocity increments. Using recent models and experimental results, we show that the flatness factor of these pdf gives a simple and direct estimate for what is called the deepness of the cascade. We analyse in this way the published data of a Direct Numerical Simulation and show that the deepness of the cascade presents the same Reynolds number dependence as in laboratory experiments. Plusieurs modèles de turbulence relient la cascade d'énergie et l'intermittence, caractérisée par l'évolution des densités de probabilité (pdf) des incréments longitudinaux de vitesse. Nous appuyant aussi bien sur des modèles récents que sur des résultats expérimentaux, nous montrons que la Curtosis de ces pdf permet une estimation simple et directe de la profondeur de la cascade. Cela nous permet de réanalyser les résultats publiés d'une simulation numérique et de montrer que la profondeur de la cascade y évolue de la même façon que pour les expériences de laboratoire en fonction du nombre de Reynolds.

Experts by experience; the views of service user educators providing feedback on medical students' work based assessments.

PubMed

Muir, Delia; Laxton, Julie Clare

2012-02-01

Assessment tools were designed to provide health and social care students with multi-sourced, interprofessional feedback in practice. This includes feedback from service users. Third year medical students at the University of Leeds were given accesses to 4 assessment tools whilst in practice. Completed assessments were then sent to the university where service users and carers worked with university tutors to give further feedback and comment on the overall development of students. Three service users then took part in a focus group and one provided written feedback. Four key themes were identified from the focus group: • Preparation and support • The design of the tools • The process of using the tools in practice • Feedback. We found that the project provided both challenges and rewards for all involved. The service user educators involved were able to bring a different and valuable perspective to formative feedback. The combination of their personal and professional experiences, along with the preparation they had received, helped bridge the gap between service users in practice and university based tutors. The findings from this study went on to inform a review of the assessment tools and revised versions are now being used. Copyright © 2011 Elsevier Ltd. All rights reserved.

Voice responses to changes in pitch of voice or tone auditory feedback

NASA Astrophysics Data System (ADS)

Sivasankar, Mahalakshmi; Bauer, Jay J.; Babu, Tara; Larson, Charles R.

2005-02-01

The present study was undertaken to examine if a subject's voice F0 responded not only to perturbations in pitch of voice feedback but also to changes in pitch of a side tone presented congruent with voice feedback. Small magnitude brief duration perturbations in pitch of voice or tone auditory feedback were randomly introduced during sustained vowel phonations. Results demonstrated a higher rate and larger magnitude of voice F0 responses to changes in pitch of the voice compared with a triangular-shaped tone (experiment 1) or a pure tone (experiment 2). However, response latencies did not differ across voice or tone conditions. Data suggest that subjects responded to the change in F0 rather than harmonic frequencies of auditory feedback because voice F0 response prevalence, magnitude, or latency did not statistically differ across triangular-shaped tone or pure-tone feedback. Results indicate the audio-vocal system is sensitive to the change in pitch of a variety of sounds, which may represent a flexible system capable of adapting to changes in the subject's voice. However, lower prevalence and smaller responses to tone pitch-shifted signals suggest that the audio-vocal system may resist changes to the pitch of other environmental sounds when voice feedback is present. .

Electromagnetic processes at low momentum transfer : a review for users

NASA Astrophysics Data System (ADS)

Parizet, M. J.; Borie, E.; Grossetête, B.; Isabelle, D. B.; Proriol, J.

Electromagnetic processes at low momentum transfer are often sources of background in many experiments. To be removed these effects must be calculated by the experimentalist, who must have a good knowledge of the validity of the theoretical formulas that he must use. Then we thought that it will be useful to prepare this review whose presentation is such that it should allow everyone to appreciate the accuracy of formulas that he must use in very complex situations. In this paper, we examine the problem related to bremsstrahlung, pair production and radiative corrections. The first part is devoted to kinematic and to the methods used to establish the corresponding cross sections. Les phénomènes électromagnétiques à faible transfert d'impulsion interviennent dans de nombreuses expériences comme des phénomènes parasites. Pour les éliminer, l'expérimentateur doit les calculer, mais il connait généralement mal la validité des formules théoriques qu'il doit alors utiliser. Il nous a donc paru utile de faire une revue dont la présentation doit permettre à chacun d'apprécier la précision des formules qu'il doit appliquer dans des situations très souvent complexes. Dans cet article, nous faisons le point, tant pour la théorie que pour l'expérience, en ce qui concerne : le rayonnement de freinage, la production de paires et les corrections radiatives. La première partie est consacrée à la cinématique des processus appréciés et aux méthodes permettant d'établir les sections efficaces correspondantes.

Erreurs grammaticales: Comment s'entrainer a les depister (Grammatical Errors: Learning How to Track Them Down).

ERIC Educational Resources Information Center

Straalen-Sanderse, Wilma van; And Others

1986-01-01

Following an experiment which revealed that production of grammatically correct sentences and correction of grammatically problematic sentences in French are essentially different skills, a progressive training method for finding and correcting grammatical errors was developed. (MSE)

Water vapour tomography using GPS phase observations: Results from the ESCOMPTE experiment

NASA Astrophysics Data System (ADS)

Nilsson, T.; Gradinarsky, L.; Elgered, G.

2007-10-01

Global Positioning System (GPS) tomography is a technique for estimating the 3-D structure of the atmospheric water vapour using data from a dense local network of GPS receivers. Several current methods utilize estimates of slant wet delays between the GPS satellites and the receivers on the ground, which are difficult to obtain with millimetre accuracy from the GPS observations. We present results of applying a new tomographic method to GPS data from the Expériance sur site pour contraindre les modèles de pollution atmosphérique et de transport d'emissions (ESCOMPTE) experiment in southern France. This method does not rely on any slant wet delay estimates, instead it uses the GPS phase observations directly. We show that the estimated wet refractivity profiles estimated by this method is on the same accuracy level or better compared to other tomographic methods. The results are in agreement with earlier simulations, for example the profile information is limited above 4 km.

LES Modeling of Supersonic Combustion at SCRAMJET Conditions

NASA Astrophysics Data System (ADS)

Vane, Zachary; Lacaze, Guilhem; Oefelein, Joseph

2016-11-01

Results from a series of large-eddy simulations (LES) of the Hypersonic International Flight Research Experiment (HIFiRE) are examined with emphasis placed on the coupled performance of the wall and combustion models. The test case of interest corresponds to the geometry and conditions found in the ground based experiments performed in the HIFiRE Direct Connect Rig (HDCR) in dual-mode operation. In these calculations, the turbulence and mixing characteristics of the high Reynolds number turbulent boundary layer with multi-species fuel injection are analyzed using a simplified chemical model and combustion closure to predict the heat release measured experimentally. These simulations are then used to identify different flame regimes in the combustor section. Concurrently, the performance of an equilibrium wall-model is evaluated in the vicinity of the fuel injectors and in the flame-holding cavity where regions of boundary layer and thermochemical non-equilibrium are present. Support for this research was provided by the Defense Advanced Research Projects Agency (DARPA).

Implicit Large Eddy Simulation of a wingtip vortex at Rec =1.2x106

NASA Astrophysics Data System (ADS)

Lombard, Jean-Eloi; Moxey, Dave; Sherwin, Spencer; SherwinLab Team

2015-11-01

We present recent developments in numerical methods for performing a Large Eddy Simulation (LES) of the formation and evolution of a wingtip vortex. The development of these vortices in the near wake, in combination with the large Reynolds numbers present in these cases, make these types of test cases particularly challenging to investigate numerically. To demonstrate the method's viability, we present results from numerical simulations of flow over a NACA 0012 profile wingtip at Rec = 1.2 x106 and compare them against experimental data, which is to date the highest Reynolds number achieved for a LES that has been correlated with experiments for this test case. Our model correlates favorably with experiment, both for the characteristic jetting in the primary vortex and pressure distribution on the wing surface. The proposed method is of general interest for the modeling of transitioning vortex dominated flows over complex geometries. McLaren Racing/Royal Academy of Engineering Research Chair.

Recherche de charginos et neutralinos dans le canal dimuon de meme signe aupres de l'experience DØ - FNAL (in French)

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

Lesne, Vincent

Dans le cadre du modele mSUGRA qui decrit un mecanisme de brisure simple de la supersym etrie, des sparticules avec des masses au-del a des limites fixees par les experiences de LEP II peuvent etre produites au Tevatron, collisionneur pmore » $$\\bar{p}$$ delivrant une energie de 1.96 TeV dans le centre de masse. Un canal privilegie pour la d´ecouverte de la supersymetrie au Tevatron est la production associee du plus leger chargino, $$\\tilde{χ}$$$±\\atop{1}$$ , et du second plus leger neutralino, $$\\tilde{χ}$$$0\\atop{2}$$ . Les modes de desintegration leptoniques, $$\\tilde{χ}$$$0\\atop{2}$$ → $$\\tilde{χ}$$$0\\atop{1}$$ ℓ +ℓ - et $$\\tilde{χ}$$$±\\atop{1}$$ → $$\\tilde{χ}$$$0\\atop{1}$$ ℓ ±ν l, conduisent a une signature claire avec trois leptons et un quantite significative d’energie transverse manquante.« less

Role of the lower esophageal sphincter on esophageal acid exposure - a review of over 2000 patients.

PubMed

Tsuboi, Kazuto; Hoshino, Masato; Sundaram, Abhishek; Yano, Fumiaki; Mittal, Sumeet K

2012-01-01

Three lower esophageal sphincter (LES) characteristics associated with gastro-esophageal reflux disease (GERD) are, LES pressure = 6 mmHg, abdominal length (AL) <1 cm and overall length (OL) <2 cm. The objective of this study was to validate this relationship and evaluate the extent of impact various LES characteristics have on the degree of distal esophageal acid exposure. A retrospective review of a prospectively maintained database identified patients who underwent esophageal manometry and pH studies at Creighton University Medical Center between 1984 and 2008. Patients with esophageal body dysmotility, prior foregut surgery, missing data, no documented symptoms or no pH study, were excluded. Study subjects were categorized as follows: (1) normal LES (N-LES): patients with LES pressure of 6-26 mmHg, AL = 1.0 cm and OL = 2 cm; (2) incompetent LES (Inc-LES): patients with LES pressure <6.0 mmHg orAL <1 cm or OL <2 cm; and (3) hypertensive LES (HTN-LES): patients with LES pressure >26.0 mmHg with AL = 1 cm and OL = 2 cm. The DeMeester score was used to compare differences in acid exposure between different groups. Two thousand and twenty patients satisfied study criteria. Distal esophageal acid exposure as reflected by the DeMeester score in patients with Inc-LES (median=20.05) was significantly higher than in patients with an N-LES (median=9.5), which in turn was significantly higher than in patients with an HTN-LES. Increasing LES pressure and AL provided protection against acid exposure in a graded fashion. Increasing number of inadequate LES characteristics were associated with an increase both in the percentage of patients with abnormal DeMeester score and the degree of acid exposure. LES pressure (=6 mmHg) and AL (<1 cm) are associated with increased lower esophageal acid exposure, and need to be addressed for definitive management of GERD.

Use of Feedback in Clinical Prediction

ERIC Educational Resources Information Center

Schroeder, Harold E.

1972-01-01

Results indicated that predictive accuracy is greater when feedback is applied to the basis for the prediction than when applied to gut" impressions. Judges forming hypotheses were also able to learn from experience. (Author)

Relative contribution of feedback processes to Arctic amplification of temperature change in MIROC GCM

NASA Astrophysics Data System (ADS)

Yoshimori, Masakazu; Watanabe, Masahiro; Abe-Ouchi, Ayako; Shiogama, Hideo; Ogura, Tomoo

2013-04-01

The finding that surface warming over the Arctic exceeds that over the rest of the world under global warming is a robust feature among general circulation models (GCMs). While various mechanisms have been proposed, quantifying their relative contributions is an important task in order to understand model behavior and operating mechanisms. Here we apply a recently proposed feedback analysis technique to a GCM under different external forcings including elevated and lowered CO2 concentrations, and increased solar irradiance. First, the contribution of feedbacks to Arctic temperature change is investigated. Surface air temperature response in the Arctic is amplified by albedo, water vapor, and large-scale condensation feedbacks from that without a feedback although a part of it is suppressed by evaporative cooling feedback. Second, the contribution of feedbacks to Arctic amplification (AA) relative to global average is investigated. Under the positive radiative forcings, the albedo feedback contributes to AA predominantly through warming the Arctic more than the low latitudes while the evaporative cooling feedback contributes to AA predominantly by cooling the low latitudes more than the Arctic. Their relative effects vary with the applied forcing, however, and the latter dominates over the former in the increased solar irradiance and lowered CO2 experiments. The large-scale condensation plus evaporative cooling feedback and the dynamical feedback contribute positively and negatively to AA, respectively. These results are consistent with an increase and a decrease of latent heat and dry-static energy transport, respectively, into the Arctic under the positive radiative forcings. An important contribution is thus made via changes in hydrological cycle and not via the 'dry' heat transport process. A larger response near the surface than aloft in the Arctic is maintained by the albedo, water vapor, and dynamical feedbacks, in which the albedo and water vapor feedbacks contribute through warming the surface more than aloft, and the dynamical feedback contributes by cooling aloft more than the surface. In our experiments, ocean and sea ice dynamics play a secondary role. It is shown that a different magnitude of CO2 increase introduces a latitudinal and seasonal difference into the feedbacks.

Probing the independence of formant control using altered auditory feedback

PubMed Central

MacDonald, Ewen N.; Purcell, David W.; Munhall, Kevin G.

2011-01-01

Two auditory feedback perturbation experiments were conducted to examine the nature of control of the first two formants in vowels. In the first experiment, talkers heard their auditory feedback with either F1 or F2 shifted in frequency. Talkers altered production of the perturbed formant by changing its frequency in the opposite direction to the perturbation but did not produce a correlated alteration of the unperturbed formant. Thus, the motor control system is capable of fine-grained independent control of F1 and F2. In the second experiment, a large meta-analysis was conducted on data from talkers who received feedback where both F1 and F2 had been perturbed. A moderate correlation was found between individual compensations in F1 and F2 suggesting that the control of F1 and F2 is processed in a common manner at some level. While a wide range of individual compensation magnitudes were observed, no significant correlations were found between individuals’ compensations and vowel space differences. Similarly, no significant correlations were found between individuals’ compensations and variability in normal vowel production. Further, when receiving normal auditory feedback, most of the population exhibited no significant correlation between the natural variation in production of F1 and F2. PMID:21361452

The foreign language effect on the self-serving bias: A field experiment in the high school classroom

PubMed Central

van Witteloostuijn, Arjen

2018-01-01

The rise of bilingual education triggers an important question: which language is preferred for a particular school activity? Our field experiment (n = 120) shows that students (aged 13–15) who process feedback in non-native English have greater self-serving bias than students who process feedback in their native Dutch. By contrast, literature on the foreign-language emotionality effect suggests a weaker self-serving bias in the non-native language, so our result adds nuance to that literature. The result is important to schools as it suggests that teachers may be able to reduce students’ defensiveness and demotivation by communicating negative feedback in the native language, and teachers may be able to increase students’ confidence and motivation by communicating positive feedback in the foreign language. PMID:29425224

Towards a Teleoperated Needle Driver Robot with Haptic Feedback for RFA of Breast Tumors under Continuous MRI1

PubMed Central

Kokes, Rebecca; Lister, Kevin; Gullapalli, Rao; Zhang, Bao; MacMillan, Alan; Richard, Howard; Desai, Jaydev P.

2009-01-01

Objective The purpose of this paper is to explore the feasibility of developing a MRI-compatible needle driver system for radiofrequency ablation (RFA) of breast tumors under continuous MRI imaging while being teleoperated by a haptic feedback device from outside the scanning room. The developed needle driver prototype was designed and tested for both tumor targeting capability as well as RFA. Methods The single degree-of-freedom (DOF) prototype was interfaced with a PHANToM haptic device controlled from outside the scanning room. Experiments were performed to demonstrate MRI-compatibility and position control accuracy with hydraulic actuation, along with an experiment to determine the PHANToM’s ability to guide the RFA tool to a tumor nodule within a phantom breast tissue model while continuously imaging within the MRI and receiving force feedback from the RFA tool. Results Hydraulic actuation is shown to be a feasible actuation technique for operation in an MRI environment. The design is MRI-compatible in all aspects except for force sensing in the directions perpendicular to the direction of motion. Experiments confirm that the user is able to detect healthy vs. cancerous tissue in a phantom model when provided with both visual (imaging) feedback and haptic feedback. Conclusion The teleoperated 1-DOF needle driver system presented in this paper demonstrates the feasibility of implementing a MRI-compatible robot for RFA of breast tumors with haptic feedback capability. PMID:19303805

Negative and positive life events are associated with small but lasting change in neuroticism.

PubMed

Jeronimus, B F; Ormel, J; Aleman, A; Penninx, B W J H; Riese, H

2013-11-01

High neuroticism is prospectively associated with psychopathology and physical health. However, within-subject changes in neuroticism due to life experiences (LEs) or state effects of current psychopathology are largely unexplored. In this 2-year follow-up study, four hypotheses were tested: (1) positive LEs (PLEs) decrease and negative LEs (NLEs) increase neuroticism; (2) LE-driven change in neuroticism is partly long-lasting; and (3) partly independent of LE-driven changes in anxiety/depression; and (4) childhood adversity (before age 16 years) moderates the influence of NLEs/PLEs on neuroticism scores in adult life. Data came from the Netherlands Study of Depression and Anxiety [NESDA, n = 2981, mean age 41.99 years (s.d. = 13.08), 66.6% women]. At follow-up (T₂) we assessed PLEs/NLEs with the List of Threatening Experiences (LTE) over the prior 24 months and categorized them over recent and distant PLE/NLE measures (1-3 and 4-24 months prior to T₂ respectively) to distinguish distant NLE/PLE-driven change in trait neuroticism (using the Dutch version of the Neuroticism-Extroversion-Openness Five Factor Inventory, NEO-FFI) from state deviations due to changes in symptoms of depression (self-rated version of the 30-item Inventory of Depressive Symptomatology, IDS-SR30) and anxiety (Beck Anxiety Inventory, BAI). Distant NLEs were associated with higher and distant PLEs with lower neuroticism scores. The effects of distant LEs were weak but long-lasting, especially for distant PLEs. Distant NLE-driven change in neuroticism was associated with change in symptoms of anxiety/depression whereas the effect of distant PLEs on neuroticism was independent of any such changes. Childhood adversity weakened the impact of distant NLEs but enhanced the impact of distant PLEs on neuroticism. Distant PLEs are associated with small but long-lasting decreases in neuroticism regardless of changes in symptom levels of anxiety/depression. Long-lasting increases in neuroticism associated with distant NLEs are mediated by anxiety/depression.

Feedback and rewards part III: commitment, goals, compensation, and job changes.

PubMed

Harolds, Jay A

2013-03-01

Formal and informal feedback is important to improve the performance, skill sets, commitment, accountability, and morale of the person being evaluated. Feedback can help people achieve their goals. Feedback is a basis for changes in compensation and other rewards. Formal reviews can also be the foundation for job changes. The latter includes promotions, lateral moves that are a better fit or will help the individual have new experiences or achieve new areas of proficiency, or finding opportunities to work outside the organization.

Facial Feedback Mechanisms in Autistic Spectrum Disorders

PubMed Central

van den Heuvel, Claudia; Smeets, Raymond C.

2008-01-01

Facial feedback mechanisms of adolescents with Autistic Spectrum Disorders (ASD) were investigated utilizing three studies. Facial expressions, which became activated via automatic (Studies 1 and 2) or intentional (Study 2) mimicry, or via holding a pen between the teeth (Study 3), influenced corresponding emotions for controls, while individuals with ASD remained emotionally unaffected. Thus, individuals with ASD do not experience feedback from activated facial expressions as controls do. This facial feedback-impairment enhances our understanding of the social and emotional lives of individuals with ASD. PMID:18293075

Le Pseudomonas: Experience du Centre des Brules D’Annaba et Revue de la Litterature

PubMed Central

Chaibdraa, A.; Medjellekh, M.S.; Saouli, A.; Bentakouk, M.C.

2008-01-01

Summary Le Pseudomonasest un agent pathogène à l'origine d'infections nosocomiales graves dans les centres des brûlés. Son opportunisme et sa virulence en font une préoccupation majeure. Ce travail se propose d'évaluer la place de cette bactérie dans l'écologie bactérienne locale et d'en apprécier la sensibilité aux antibiotiques. Cette étude rétrospective préliminaire porte sur la période de juin 2003 à décembre 2005. Elle intéresse l'ensemble des prélèvements bactériologiques ayant pu être réalisés au centre des brûlés d'Annaba. L'effectif est de 633 micro-organismes isolés dont 128 Pseudomonas (20,2%): 127 aeruginosa (99,2%), 1 fluorescens (0,8%); distribution selon le site de prélèvement: écouvillon (87,5%), prélèvement trachéobronchique (4,6%), hémoculture (3,1%), cathéters (1,6%), urine (1,6%) et sonde urinaire (1,6%). Le pyocyanique se situe après le staphylocoque pour les prélèvements précoces et repasse en tête après un séjour supérieur à une semaine, où 89% des pyocyaniques sont identifiés. Il est en première position dans les pneumopathies sous ventilation assistée invasive. Il se classe troisième dans les hémocultures et les cultures de cathéters. Dans les infections urinaires il est devancé par Candida et la flore périnéale. Les 128 antibiogrammes regroupent 314 réponses sensibles. La sensibilité à plus de deux antibiotiques est de 68%, à deux antibiotiques 24% et à un antibiotique 8%. Seules quatre molécules restent actives: ciprofloxacine > péfloxacine > pipéracilline > ceftazidime. Une résistance absolue est retrouvée pour trois Pseudomonas (2,4%). Le pronostic sévère des infections nosocomiales à pyocyanique et les risques d'options thérapeutiques très limitées font toute leur gravité, d'où l'intérêt de respecter des règles strictes de prescription des antibiotiques et des mesures de prévention. PMID:21991140

Using Neurological Feedback to Enhance Resilience and Recuperation

DTIC Science & Technology

2011-04-01

well-being, stress management and experience, and physiological markers of stress, anxiety and depression. During the upcoming symposium the...health and well-being, stress management and experience, and physiological markers of stress, anxiety and depression. During the upcoming symposium the...120 seconds are necessary to calculate reliable HRV information. This implies that feedback based on this method is always delayed and can not be used

How Should Different Types of Feedback Be Administered to Create More Effective Learning among Advanced ESL Writing Students? A Student Perspective

ERIC Educational Resources Information Center

Bao, Ze

2015-01-01

This paper is set in the context of my experience in advanced ESL writing classes at two Canadian universities. Based on my experience and the research literature, several types of feedback should be administered by teachers to create more effective learning opportunities among advanced ESL writing students. In this paper, I examine the advantages…

Chronic Treatment with Haloperidol Induces Deficits in Working Memory and Feedback Effects of Interval Timing

ERIC Educational Resources Information Center

Lustig, C.; Meck, W.H.

2005-01-01

Normal participants (n=5) having no experience with antipsychotic drugs and medicated participants (n=5) with clinical experience with chronic low doses of haloperidol (3-10mg/day for 2-4 months) in the treatment of neuroses were evaluated for the effects of inter-trial interval (ITI) feedback on a discrete-trials peak-interval timing procedure.…

Effect of Feedback Strategy and Motivation of Achievement to Improving Learning Results Concept in Learning Civic Education in Vocational High School

ERIC Educational Resources Information Center

Sumarno; Setyosari, Punaji; Haryono

2017-01-01

This study aims to examine the effect of feedback strategies on understanding and applying the concept of National ideology to students who have different achievement motivation, on learning Citizenship Education in vocational high schools. This research uses quasi experiment research design (Quasi Experiment). The subjects of this study were 133…

Role of combined tactile and kinesthetic feedback in minimally invasive surgery.

PubMed

Lim, Soo-Chul; Lee, Hyung-Kew; Park, Joonah

2014-10-18

Haptic feedback is of critical importance in surgical tasks. However, conventional surgical robots do not provide haptic feedback to surgeons during surgery. Thus, in this study, a combined tactile and kinesthetic feedback system was developed to provide haptic feedback to surgeons during robotic surgery. To assess haptic feasibility, the effects of two types of haptic feedback were examined empirically - kinesthetic and tactile feedback - to measure object-pulling force with a telesurgery robotics system at two desired pulling forces (1 N and 2 N). Participants answered a set of questionnaires after experiments. The experimental results reveal reductions in force error (39.1% and 40.9%) when using haptic feedback during 1 N and 2 N pulling tasks. Moreover, survey analyses show the effectiveness of the haptic feedback during teleoperation. The combined tactile and kinesthetic feedback of the master device in robotic surgery improves the surgeon's ability to control the interaction force applied to the tissue. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Delayed, but not immediate, feedback after multiple-choice questions increases performance on a subsequent short-answer, but not multiple-choice, exam: evidence for the dual-process theory of memory.

PubMed

Sinha, Neha; Glass, Arnold Lewis

2015-01-01

Three experiments, two performed in the laboratory and one embedded in a college psychology lecture course, investigated the effects of immediate versus delayed feedback following a multiple-choice exam on subsequent short answer and multiple-choice exams. Performance on the subsequent multiple-choice exam was not affected by the timing of the feedback on the prior exam; however, performance on the subsequent short answer exam was better following delayed than following immediate feedback. This was true regardless of the order in which immediate versus delayed feedback was given. Furthermore, delayed feedback only had a greater effect than immediate feedback on subsequent short answer performance following correct, confident responses on the prior exam. These results indicate that delayed feedback cues a student's prior response and increases subsequent recollection of that response. The practical implication is that delayed feedback is better than immediate feedback during academic testing.

Study of Hydrokinetic Turbine Arrays with Large Eddy Simulation

NASA Astrophysics Data System (ADS)

Sale, Danny; Aliseda, Alberto

2014-11-01

Marine renewable energy is advancing towards commercialization, including electrical power generation from ocean, river, and tidal currents. The focus of this work is to develop numerical simulations capable of predicting the power generation potential of hydrokinetic turbine arrays-this includes analysis of unsteady and averaged flow fields, turbulence statistics, and unsteady loadings on turbine rotors and support structures due to interaction with rotor wakes and ambient turbulence. The governing equations of large-eddy-simulation (LES) are solved using a finite-volume method, and the presence of turbine blades are approximated by the actuator-line method in which hydrodynamic forces are projected to the flow field as a body force. The actuator-line approach captures helical wake formation including vortex shedding from individual blades, and the effects of drag and vorticity generation from the rough seabed surface are accounted for by wall-models. This LES framework was used to replicate a previous flume experiment consisting of three hydrokinetic turbines tested under various operating conditions and array layouts. Predictions of the power generation, velocity deficit and turbulence statistics in the wakes are compared between the LES and experimental datasets.

Power-law versus log-law in wall-bounded turbulence: A large-eddy simulation perspective

NASA Astrophysics Data System (ADS)

Cheng, W.; Samtaney, R.

2014-01-01

The debate whether the mean streamwise velocity in wall-bounded turbulent flows obeys a log-law or a power-law scaling originated over two decades ago, and continues to ferment in recent years. As experiments and direct numerical simulation can not provide sufficient clues, in this study we present an insight into this debate from a large-eddy simulation (LES) viewpoint. The LES organically combines state-of-the-art models (the stretched-vortex model and inflow rescaling method) with a virtual-wall model derived under different scaling law assumptions (the log-law or the power-law by George and Castillo ["Zero-pressure-gradient turbulent boundary layer," Appl. Mech. Rev. 50, 689 (1997)]). Comparison of LES results for Reθ ranging from 105 to 1011 for zero-pressure-gradient turbulent boundary layer flows are carried out for the mean streamwise velocity, its gradient and its scaled gradient. Our results provide strong evidence that for both sets of modeling assumption (log law or power law), the turbulence gravitates naturally towards the log-law scaling at extremely large Reynolds numbers.

LES-based characterization of a suction and oscillatory blowing fluidic actuator

NASA Astrophysics Data System (ADS)

Kim, Jeonglae; Moin, Parviz

2015-11-01

Recently, a novel fluidic actuator using steady suction and oscillatory blowing was developed for control of turbulent flows. The suction and oscillatory blowing (SaOB) actuator combines steady suction and pulsed oscillatory blowing into a single device. The actuation is based upon a self-sustained mechanism of confined jets and does not require any moving parts. The control output is determined by a pressure source and the geometric details, and no additional input is needed. While its basic mechanisms have been investigated to some extent, detailed characteristics of internal turbulent flows are not well understood. In this study, internal flows of the SaOB actuator are simulated using large-eddy simulation (LES). Flow characteristics within the actuator are described in detail for a better understanding of the physical mechanisms and improving the actuator design. LES predicts the self-sustained oscillations of the turbulent jet. Switching frequency, maximum velocity at the actuator outlets, and wall pressure distribution are in good agreement with the experimental measurements. The computational results are used to develop simplified boundary conditions for numerical experiments of active flow control. Supported by the Boeing company.

Syndromes drépanocytaires majeurs et infections associées chez l ’enfant au Burkina Faso

PubMed Central

Douamba, Sonia; Nagalo, Kisito; Tamini, Laure; Traoré, Ismaël; Kam, Madibèlè; Kouéta, Fla; Yé, Diarra

2017-01-01

Introduction Le but de cette étude était d’étudier les infections chez les enfants présentant un syndrome drépanocytaire majeur. Méthodes Étude hospitalière monocentrique, rétrospective descriptive sur dix années menée à Ouagadougou, Burkina Faso. Étaient inclus tous les enfants porteurs d'un syndrome drépanocytaire majeur (homozygote SS et double hétérozygote SC, SDPunjab, Sβ thalassémique, SOArab et SE) hospitalisés pour une infection bactérienne confirmée à la microbiologie. Résultats Cent trente trois patients répondaient à nos critères d’inclusion. Le phénotype SS représentait 63,2% des cas et le SC 36,8%. La fréquence des infections était de 21,8%. Celles-ci touchaient dans 45,9% des cas les enfants âgés de 0 à 5 ans. Les signes les plus fréquents étaient les douleurs ostéoarticulaires (42,1%), la toux (25,7%), les douleurs abdominales (23,3%), la pâleur (43,6%). Les broncho-pneumopathies (31,6%), le paludisme (16,5%), les ostéomyélites (12,8%) et les septicémies (10,5%) étaient les principaux diagnostics trouvés. Les agents pathogènes isolés étaient Streptococcus pneumoniae (35,5%) et Salmonella sp (33,3%). Les céphalosporines de 3e génération étaient les antibiotiques les plus fréquemment prescrits. Le taux brut de mortalité était de 7,5%. Conclusion Les infections bactériennes et le paludisme dominent le tableau des infections chez l'enfant drépanocytaire majeur au Centre Hospitalier Universitaire Pédiatrique Charles De Gaulle. Les auteurs recommandent la mise en place d’un programme national de prise en charge de la drépanocytose, ce qui permettrait de prévenir voire réduire la survenue des infections chez les enfants drépanocytaires. PMID:28450986

Facteurs de risque de la tuberculose multi-résistante dans la ville de Kinshasa en République Démocratique du Congo

PubMed Central

Misombo-Kalabela, André; Nguefack-Tsague, Georges; Kalla, Ginette Claude Mireille; Ze, Emmanuel Afane; Diangs, Kimpanga; Panda, Tshapenda; Kebela, Ilunga; Fueza, Serge Bisuta; Magazani, Nzanzu; Mbopi-Kéou, François-Xavier

2016-01-01

Introduction L'objectif de cette étude était de déterminer les facteurs de risque associés à la tuberculose multi résistance à Kinshasa en République Démocratique du Congo. Méthodes Il s'agissait d'une étude cas témoins. Les cas comprenaient tous les patients tuberculeux résistants à la rifampicine et à l'isoniazide notifiés à Kinshasa de janvier 2012 à juin 2013. Les témoins étaient les patients tuberculeux traités durant la même période que les cas et qui à la fin du traitement étaient déclarés guéris. Pour cette étude, nous avons obtenu une clairance éthique. Résultats L’échantillon était constitué de 213 participants dont 132 hommes (62%) et 81 femmes (38%). L’âge médian était de 31ans (16-73 ans). Les facteurs associés significatifs (p< 0,05) à la tuberculose multi résistante étaient le non-respect des heures de prise de médicaments (0R = 111) (80% chez les cas et 4% chez les témoins), l’échec au traitement (0R = 20) (76% chez les cas et 13% chez les témoins); la notion de tuberculose multi résistante dans la famille (0R = 6.4) (28% chez les cas et 6% chez les témoins); la méconnaissance de la tuberculose multi résistante (0R = 3.2) (31% chez les cas et 59% chez les témoins); un séjour en prison (0R = 7.6) (10% chez les cas et 1% chez les témoins) et l'interruption du traitement (0R = 6.1) ( 59% chez les cas et 19% chez les témoins). Conclusion L’émergence de la tuberculose multi résistante peut être évitée par la mise en place des stratégies de diagnostic et de traitement appropriées. PMID:27516818

Tap Arduino: An Arduino microcontroller for low-latency auditory feedback in sensorimotor synchronization experiments.

PubMed

Schultz, Benjamin G; van Vugt, Floris T

2016-12-01

Timing abilities are often measured by having participants tap their finger along with a metronome and presenting tap-triggered auditory feedback. These experiments predominantly use electronic percussion pads combined with software (e.g., FTAP or Max/MSP) that records responses and delivers auditory feedback. However, these setups involve unknown latencies between tap onset and auditory feedback and can sometimes miss responses or record multiple, superfluous responses for a single tap. These issues may distort measurements of tapping performance or affect the performance of the individual. We present an alternative setup using an Arduino microcontroller that addresses these issues and delivers low-latency auditory feedback. We validated our setup by having participants (N = 6) tap on a force-sensitive resistor pad connected to the Arduino and on an electronic percussion pad with various levels of force and tempi. The Arduino delivered auditory feedback through a pulse-width modulation (PWM) pin connected to a headphone jack or a wave shield component. The Arduino's PWM (M = 0.6 ms, SD = 0.3) and wave shield (M = 2.6 ms, SD = 0.3) demonstrated significantly lower auditory feedback latencies than the percussion pad (M = 9.1 ms, SD = 2.0), FTAP (M = 14.6 ms, SD = 2.8), and Max/MSP (M = 15.8 ms, SD = 3.4). The PWM and wave shield latencies were also significantly less variable than those from FTAP and Max/MSP. The Arduino missed significantly fewer taps, and recorded fewer superfluous responses, than the percussion pad. The Arduino captured all responses, whereas at lower tapping forces, the percussion pad missed more taps. Regardless of tapping force, the Arduino outperformed the percussion pad. Overall, the Arduino is a high-precision, low-latency, portable, and affordable tool for auditory experiments.

The Sense of Agency Is More Sensitive to Manipulations of Outcome than Movement-Related Feedback Irrespective of Sensory Modality

PubMed Central

David, Nicole; Skoruppa, Stefan; Gulberti, Alessandro

2016-01-01

The sense of agency describes the ability to experience oneself as the agent of one's own actions. Previous studies of the sense of agency manipulated the predicted sensory feedback related either to movement execution or to the movement’s outcome, for example by delaying the movement of a virtual hand or the onset of a tone that resulted from a button press. Such temporal sensorimotor discrepancies reduce the sense of agency. It remains unclear whether movement-related feedback is processed differently than outcome-related feedback in terms of agency experience, especially if these types of feedback differ with respect to sensory modality. We employed a mixed-reality setup, in which participants tracked their finger movements by means of a virtual hand. They performed a single tap, which elicited a sound. The temporal contingency between the participants’ finger movements and (i) the movement of the virtual hand or (ii) the expected auditory outcome was systematically varied. In a visual control experiment, the tap elicited a visual outcome. For each feedback type and participant, changes in the sense of agency were quantified using a forced-choice paradigm and the Method of Constant Stimuli. Participants were more sensitive to delays of outcome than to delays of movement execution. This effect was very similar for visual or auditory outcome delays. Our results indicate different contributions of movement- versus outcome-related sensory feedback to the sense of agency, irrespective of the modality of the outcome. We propose that this differential sensitivity reflects the behavioral importance of assessing authorship of the outcome of an action. PMID:27536948

Feedback-Assisted Extension of the Tokamak Operating Space to Low Safety Factor

NASA Astrophysics Data System (ADS)

Hanson, J. M.

2013-10-01

Recent DIII-D experiments have demonstrated stable operation at very low edge safety factor, q95 <~ 2 through the use of magnetic feedback to control the n = 1 resistive wall mode (RWM) instability. The performance of tokamak fusion devices may benefit from increased plasma current, and thus, decreased q. However, disruptive stability limits are commonly encountered in experiments at qedge ~ 2 (limited plasmas) and q95 ~ 2 (diverted plasmas), limiting exploration of low q regimes. In the recent DIII-D experiments, the impact and control of key disruptive instabilities was studied. Locked n = 1 modes with exponential growth times on the order of the wall eddy current decay timescale τw preceded disruptions at q95 = 2 . The instabilities have a poloidal structure that is consistent with VALEN simulations of the RWM mode structure at q95 = 2 . Applying proportional gain magnetic feedback control of the n = 1 mode resulted in stabilized operation with q95 reaching 1.9, and an extension of the discharge lifetime for > 100τw . Loss of feedback control was accompanied by power supply saturation, followed by a rapidly growing n = 1 mode and disruption. Comparisons of the feedback dynamics with VALEN simulations will be presented. The DIII-D results complement and will be discussed alongside recent RFX-MOD demonstrations of RWM control using magnetic feedback in limited tokamak discharges with qedge < 2. These results call attention to the utility of magnetic feedback in significantly extending the tokamak operational space and potentially opening a new route to economical fusion power production. Supported by the US Department of Energy under DE-FG02-04ER54761 and DE-FC02-04ER54698.

The Role of Implicit Negative Feedback in SLA: Models and Recasts in Japanese and Spanish.

ERIC Educational Resources Information Center

Long, Michael; Inagaki, Shunji; Ortega, Lourdes

1998-01-01

Two experiments were conducted to assess relative utility of models and recasts in second-language (L2) Japanese and Spanish. Using pretest, posttest, control group design, each study provided evidence of adults' ability to learn from implicit negative feedback; in one case, support for notion that reactive implicit negative feedback can be more…

Working Smarter, Not Working Harder: Revisiting Teacher Feedback in the L2 Writing Classroom

ERIC Educational Resources Information Center

Lee, Icy

2011-01-01

Although second language (L2) teachers spend a significant amount of time marking students' writing, many of them feel that their efforts do not pay off. While students want teachers to give them feedback on their writing and value teacher feedback, they might experience feelings of frustration and confusion once they receive it. What is amiss in…

ERP Correlates of Language-Specific Processing of Auditory Pitch Feedback during Self-Vocalization

ERIC Educational Resources Information Center

Chen, Zhaocong; Liu, Peng; Wang, Emily Q.; Larson, Charles R.; Huang, Dongfeng; Liu, Hanjun

2012-01-01

The present study investigated whether the neural correlates for auditory feedback control of vocal pitch can be shaped by tone language experience. Event-related potentials (P2/N1) were recorded from adult native speakers of Mandarin and Cantonese who heard their voice auditory feedback shifted in pitch by -50, -100, -200, or -500 cents when they…

Student Voices about the Role Feedback Plays in the Enhancement of Their Learning

ERIC Educational Resources Information Center

Plank, Christine; Dixon, Helen; Ward, Gillian

2014-01-01

If feedback is to be framed as purposeful dialogue then both students and teachers have significant roles to play. Students must be willing and able to provide feedback to teachers not only about their learning needs but also about the teaching they experience. In turn, teachers must create the conditions that support active student learning and…

What Supervisors Say in Their Feedback: Construction of CanMEDS Roles in Workplace Settings

ERIC Educational Resources Information Center

Renting, Nienke; Dornan, Tim; Gans, Rijk O. B.; Borleffs, Jan C. C.; Cohen-Schotanus, Janke; Jaarsma, A. Debbie C.

2016-01-01

The CanMEDS framework has been widely adopted in residency education and feedback processes are guided by it. It is, however, only one of many influences on what is actually discussed in feedback. The sociohistorical culture of medicine and individual supervisors' contexts, experiences and beliefs are also influential. Our aim was to find how…

Immediate vs. Delayed Feedback in a Computer-Managed Test: Effects on Long-Term Retention. Technical Report, March 1976-August 1976.

ERIC Educational Resources Information Center

Sturges, Persis T.

This experiment was designed to test the effect of immediate and delayed feedback on retention of learning in an educational situation. Four groups of college undergraduates took a multiple-choice computer-managed test. Three of these groups received informative feedback (the entire item with the correct answer identified) either: (1) immediately…

Health professionals' perceptions about their clinical performance and the influence of audit and feedback on their intentions to improve practice: a theory-based study in Dutch intensive care units.

PubMed

Gude, Wouter T; Roos-Blom, Marie-José; van der Veer, Sabine N; Dongelmans, Dave A; de Jonge, Evert; Francis, Jill J; Peek, Niels; de Keizer, Nicolette F

2018-02-17

Audit and feedback aims to guide health professionals in improving aspects of their practice that need it most. Evidence suggests that feedback fails to increase accuracy of professional perceptions about clinical performance, which likely reduces audit and feedback effectiveness. This study investigates health professionals' perceptions about their clinical performance and the influence of feedback on their intentions to change practice. We conducted an online laboratory experiment guided by Control Theory with 72 intensive care professionals from 21 units. For each of four new pain management indicators, we collected professionals' perceptions about their clinical performance; peer performance; targets; and improvement intentions before and after receiving first-time feedback. An electronic audit and feedback dashboard provided ICU's own performance, median and top 10% peer performance, and improvement recommendations. The experiment took place approximately 1 month before units enrolled into a cluster-randomised trial assessing the impact of adding a toolbox with suggested actions and materials to improve intensive care pain management. During the experiment, the toolbox was inaccessible; all participants accessed the same version of the dashboard. We analysed 288 observations. In 53.8%, intensive care professionals overestimated their clinical performance; but in only 13.5%, they underestimated it. On average, performance was overestimated by 22.9% (on a 0-100% scale). Professionals similarly overestimated peer performance, and set targets 20.3% higher than the top performance benchmarks. In 68.4% of cases, intentions to improve practice were consistent with actual gaps in performance, even before professionals had received feedback; which increased to 79.9% after receiving feedback (odds ratio, 2.41; 95% CI, 1.53 to 3.78). However, in 56.3% of cases, professionals still wanted to improve care aspects at which they were already top performers. Alternatively, in 8.3% of cases, they lacked improvement intentions because they did not consider indicators important; did not trust the data; or deemed benchmarks unrealistic. Audit and feedback helps health professionals to work on aspects for which improvement is recommended. Given the abundance of professionals' prior good improvement intentions, the limited effects typically found by audit and feedback studies are likely predominantly caused by barriers to translation of intentions into actual change in clinical practice. ClinicalTrials.gov NCT02922101 . Registered 26 September 2016.

'I wish someone watched me interview:' medical student insight into observation and feedback as a method for teaching communication skills during the clinical years.

PubMed

Schopper, Heather; Rosenbaum, Marcy; Axelson, Rick

2016-11-09

Experts suggest observation and feedback is a useful tool for teaching and evaluating medical student communication skills during the clinical years. Failing to do this effectively risks contributing to deterioration of students' communication skills during the very educational period in which they are most important. While educators have been queried about their thoughts on this issue, little is known about what this process is like for learners and if they feel they get educational value from being observed. This study explored student perspectives regarding their experiences with clinical observation and feedback on communication skills. A total of 125 senior medical students at a U.S. medical school were interviewed about their experiences with observation and feedback. Thematic analysis of interview data identified common themes among student responses. The majority of students reported rarely being observed interviewing, and they reported receiving feedback even less frequently. Students valued having communication skills observed and became more comfortable with observation the more it occurred. Student-identified challenges included supervisor time constraints and grading based on observation. Most feedback focused on information gathering and was commonly delayed until well after the observed encounter. Eliciting students' perspectives on the effect of observation and feedback on the development of their communication skills is a unique way to look at this topic, and brings to light many student-identified obstacles and opportunities to maximize the educational value of observation and feedback for teaching communication, including increasing the number of observations, disassociating observation from numerically scored evaluation, training faculty to give meaningful feedback, and timing the observation/feedback earlier in clerkships.

Large-Eddy Simulation of Atmospheric Boundary-Layer Flow Through a Wind Farm Sited on Topography

NASA Astrophysics Data System (ADS)

Shamsoddin, Sina; Porté-Agel, Fernando

2017-04-01

Large-eddy simulation (LES) has recently been well validated and applied in the context of wind turbines over flat terrain; however, to date its accuracy has not been tested systematically in the case of turbine-wake flows over topography. Here, we investigate the wake flow in a wind farm situated on hilly terrain using LES for a case where wind-tunnel experimental data are available. To this end, first boundary-layer flow is simulated over a two-dimensional hill in order to characterize the spatial distribution of the mean velocity and the turbulence statistics. A flow simulation is then performed through a wind farm consisting of five horizontal-axis wind turbines sited over the same hill in an aligned layout. The resulting flow characteristics are compared with the former case, i.e., without wind turbines. To assess the validity of the simulations, the results are compared with the wind-tunnel measurements. It is found that LES can reproduce the flow field effectively, and, specifically, the speed-up over the hilltop and the velocity deficit and turbulence intensity enhancement induced by the turbines are well captured by the simulations. Besides, the vertical profiles of the mean velocity and turbulence intensity at different streamwise positions match well those for the experiment. In addition, another numerical experiment is carried out to show how higher (and more realistic) thrust coefficients of the turbines lead to stronger wakes and, at the same time, higher turbulence intensities.

Feedback control of one's own action: Self-other sensory attribution in motor control.

PubMed

Asai, Tomohisa

2015-12-15

The sense of agency, the subjective experience of controlling one's own action, has an important function in motor control. When we move our own body or even external tools, we attribute that movement to ourselves and utilize that sensory information in order to correct "our own" movement in theory. The dynamic relationship between conscious self-other attribution and feedback control, however, is still unclear. Participants were required to make a sinusoidal reaching movement and received its visual feedback (i.e., cursor). When participants received a fake movement that was spatio-temporally close to their actual movement, illusory self-attribution of the fake movement was observed. In this situation, since participants tried to control the cursor but it was impossible to do so, the movement error was increased (Experiment 1). However, when the visual feedback was reduced to make self-other attribution difficult, there was no further increase in the movement error (Experiment 2). These results indicate that conscious self-other sensory attribution might coordinate sensory input and motor output. Copyright © 2015 Elsevier Inc. All rights reserved.

Description and effects of sequential behavior practice in teacher education.

PubMed

Sharpe, T; Lounsbery, M; Bahls, V

1997-09-01

This study examined the effects of a sequential behavior feedback protocol on the practice-teaching experiences of undergraduate teacher trainees. The performance competencies of teacher trainees were analyzed using an alternative opportunities for appropriate action measure. Data support the added utility of sequential (Sharpe, 1997a, 1997b) behavior analysis information in systematic observation approaches to teacher education. One field-based undergraduate practicum using sequential behavior (i.e., field systems analysis) principles was monitored. Summarized are the key elements of the (a) classroom instruction provided as a precursor to the practice teaching experience, (b) practice teaching experience, and (c) field systems observation tool used for evaluation and feedback, including multiple-baseline data (N = 4) to support this approach to teacher education. Results point to (a) the strong relationship between sequential behavior feedback and the positive change in four preservice teachers' day-to-day teaching practices in challenging situational contexts, and (b) the relationship between changes in teacher practices and positive changes in the behavioral practices of gymnasium pupils. Sequential behavior feedback was also socially validated by the undergraduate participants and Professional Development School teacher supervisors in the study.

Impaired Feedforward Control and Enhanced Feedback Control of Speech in Patients with Cerebellar Degeneration

PubMed Central

Agnew, Zarinah; Nagarajan, Srikantan; Houde, John; Ivry, Richard B.

2017-01-01

The cerebellum has been hypothesized to form a crucial part of the speech motor control network. Evidence for this comes from patients with cerebellar damage, who exhibit a variety of speech deficits, as well as imaging studies showing cerebellar activation during speech production in healthy individuals. To date, the precise role of the cerebellum in speech motor control remains unclear, as it has been implicated in both anticipatory (feedforward) and reactive (feedback) control. Here, we assess both anticipatory and reactive aspects of speech motor control, comparing the performance of patients with cerebellar degeneration and matched controls. Experiment 1 tested feedforward control by examining speech adaptation across trials in response to a consistent perturbation of auditory feedback. Experiment 2 tested feedback control, examining online corrections in response to inconsistent perturbations of auditory feedback. Both male and female patients and controls were tested. The patients were impaired in adapting their feedforward control system relative to controls, exhibiting an attenuated anticipatory response to the perturbation. In contrast, the patients produced even larger compensatory responses than controls, suggesting an increased reliance on sensory feedback to guide speech articulation in this population. Together, these results suggest that the cerebellum is crucial for maintaining accurate feedforward control of speech, but relatively uninvolved in feedback control. SIGNIFICANCE STATEMENT Speech motor control is a complex activity that is thought to rely on both predictive, feedforward control as well as reactive, feedback control. While the cerebellum has been shown to be part of the speech motor control network, its functional contribution to feedback and feedforward control remains controversial. Here, we use real-time auditory perturbations of speech to show that patients with cerebellar degeneration are impaired in adapting feedforward control of speech but retain the ability to make online feedback corrections; indeed, the patients show an increased sensitivity to feedback. These results indicate that the cerebellum forms a crucial part of the feedforward control system for speech but is not essential for online, feedback control. PMID:28842410

Les recommandations thérapeutiques relatives aux effets secondaires extrapyramidaux associés à l’utilisation d’antipsychotiques de deuxième génération chez les enfants et les adolescents

PubMed Central

Pringsheim, Tamara; Doja, Asif; Belanger, Stacey; Patten, Scott

2012-01-01

HISTORIQUE ET OBJECTIF : L’utilisation d’antipsychotiques augmente chez les enfants. Le présent article visait à orienter les cliniciens quant à la prise en charge clinique des effets secondaires extrapyramidaux des antipsychotiques de deuxième génération. MÉTHODOLOGIE : Les publications, les entrevues avec des informateurs clés et des échanges avec les membres d’un groupe de discussion et les partenaires ont permis de déterminer les principaux secteurs cliniques d’orientation et les préférences quant à la structure des présentes recommandations. Les membres responsables des lignes directrices ont reçu le projet de recommandations, ont évalué l’information recueillie grâce à une analyse bibliographique systématique et ont utilisé un processus de groupe nominal pour parvenir à un consensus quant aux recommandations thérapeutiques. Les lignes directrices contiennent une description des anomalies neurologiques souvent observées avec l’utilisation d’antipsychotiques ainsi que les recommandations sur le moyen d’examiner et de quantifier ces anomalies. Une démarche séquentielle sur la prise en charge des anomalies neurologiques est présentée. RÉSULTATS : On peut observer plusieurs types de symptômes extrapyramidaux attribuables à l’utilisation d’antipsychotiques chez les enfants, y compris la dystonie aiguë, l’akathisie, le parkinsonisme et la dyskinésie tardive, toutes induites par les neuroleptiques, de même que la dystonie tardive, l’akathisie tardive et les dyskinésies de sevrage. La forte majorité des données probantes sur le traitement des troubles du mouvement induits par les antipsychotiques proviennent de patients adultes atteints de schizophrénie. Étant donné le peu de données pédiatriques, les recommandations découlent de publications portant tant sur des adultes que sur des enfants. Compte tenu des limites de généralisation des données provenant de sujets adultes pour des enfants, il faudrait évaluer ces recommandations d’après les avis d’experts plutôt que d’après les données probantes. CONCLUSION : Les cliniciens doivent savoir que les antipsychotiques de deuxième génération ont le potentiel d’induire des effets secondaires neurologiques et devraient faire preuve d’une extrême vigilance lorsqu’ils en prescrivent. PMID:24082814

Student Feedback of Career Development Workshops for Program Improvement

NASA Astrophysics Data System (ADS)

LeBeau, J. E.; Pressley, S. N.

2016-12-01

A number of techniques are employed each year to evaluate the effectiveness of and to identify opportunities for improvement in the Laboratory for Atmospheric Research (LAR) REU program at Washington State University. For example, information gathered from pre-/post-surveys and pre-/post-interviews provides information regarding students' perceptions and levels of experience with the scientific process, career and academic goals, and motivation for joining the REU program. Poster session rubrics assess students' abilities to summarize their experiences in a professional setting. Alumni surveys gauge former participants' perceptions of the REU experience. One seemingly simple and highly useful, but often less documented, component of the evaluation process for program improvement is the use of workshop feedback forms. Weekly workshops are designed to provide students with enhanced knowledge and skills in the area of atmospheric chemistry as well as research design skills, academic and career guidance, and presentation skills. According to previous years' evaluation reports, workshops are largely beneficial to students for learning new skills. Yet, students suggest a number of recommendations that may benefit any REU program, such as: providing slides beforehand to provide a framework for the upcoming workshop, having instructors speak in more student-friendly language, covering higher-level topics, and including more hands-on, instructor-guided practice during the workshops. Thus, workshop feedback forms provide meaningful feedback to increase learning outcomes and enhance the REU student experience. This presentation will offer ideas gathered from over five years of workshop feedback forms that, while somewhat specific to workshops offered for the LAR REU, can offer faculty and PIs insight into the student experience, enhancing their ability to improve programming and achieve greater learning outcomes.

mHealth Intervention Elements and User Characteristics Determine Utility: A Mixed-Methods Analysis.

PubMed

Nelson, Lyndsay A; Mulvaney, Shelagh A; Johnson, Kevin B; Osborn, Chandra Y

2017-01-01

Mobile health (mHealth) interventions are improving the medication adherence of adults with type 2 diabetes mellitus (T2DM), but few studies examine how users experience these interventions. Therefore, we used a mixed-methods approach to understand how T2DM users experience a text messaging and interactive voice response (IVR)-delivered medication adherence intervention called MEssaging for Diabetes (MED). Adults with T2DM used MED as part of a 3-month pilot study. MED sends daily tailored text messages addressing adherence barriers, daily assessment text messages asking about adherence, and weekly tailored IVR calls providing adherence feedback, encouragement, and questions to facilitate problem solving. Sixty participants completed feedback interviews. We used a mixed-methods approach to understand their experience, examining associations between participants' characteristics and their feedback. Participants who completed feedback interviews were on average 50.0 ± 10.1 years old; 65% female, 62% non-white; 15% had less than a high school education, 70% had annual incomes less than $20K; and average hemoglobin A1c was 8.0% ± 1.9%. Participants rated each intervention element favorably; common reasons for MED's helpfulness included receiving novel information about diabetes medications, emotional support, and reminders to take medication. People who were younger and more recently diagnosed with T2DM had more favorable experiences using MED. In general, users valued text messages more than IVR calls. Consideration of the user experience is critical for developing engaging mHealth interventions. User feedback reveals what mHealth elements have the most value and why, which users to target, and how to optimize an intervention's utility and appeal.

The enhancement of beneficial effects following audio feedback by cognitive preparation in the treatment of social anxiety: a single-session experiment.

PubMed

Nilsson, Jan-Erik; Lundh, Lars-Gunnar; Faghihi, Shahriar; Roth-Andersson, Gun

2011-12-01

According to cognitive models, negatively biased processing of the publicly observable self is an important aspect of social phobia; if this is true, effective methods for producing corrective feedback concerning the public self should be strived for. Video feedback is proven effective, but since one's voice represents another aspect of the self, audio feedback should produce equivalent results. This is the first study to assess the enhancement of audio feedback by cognitive preparation in a single-session randomized controlled experiment. Forty socially anxious participants were asked to give a speech, then to listen to and evaluate a taped recording of their performance. Half of the sample was given cognitive preparation prior to the audio feedback and the remainder received audio feedback only. Cognitive preparation involved asking participants to (1) predict in detail what they would hear on the audiotape, (2) form an image of themselves giving the speech and (3) listen to the audio recording as though they were listening to a stranger. To assess generalization effects all participants were asked to give a second speech. Audio feedback with cognitive preparation was shown to produce less negative ratings after the first speech, and effects generalized to the evaluation of the second speech. More positive speech evaluations were associated with corresponding reductions of state anxiety. Social anxiety as indexed by the Implicit Association Test was reduced in participants given cognitive preparation. Small sample size; analogue study. Audio feedback with cognitive preparation may be utilized as a treatment intervention for social phobia. Copyright © 2011 Elsevier Ltd. All rights reserved.

Facteurs de risque dans le trouble déficitaire de l’attention et de l’hyperactivité: étude familiale

PubMed Central

Poissant, Hélène; Rapin, Lucile

2012-01-01

Résumé Objectif: Notre étude a pour but d’évaluer les facteurs de risque associés au trouble déficitaire de l’attention et de l’hyperactivité (TDAH) en termes de comorbidités et de facteurs d’adversité à l’intérieur des familles avec un TDAH. Méthodologie: 137 parents de 104 enfants avec un TDAH et 40 parents de 34 enfants contrôles ont répondu aux items d’un questionnaire. Des tests Chi-carrés et des tests de Student ont mesuré l’association de chaque item avec les groupes et les différences entre les groupes. Résultats: Les enfants avec un TDAH avaient des performances scolaires plus faibles et une plus forte prévalence des troubles d’apprentissage, oppositionnel, des conduites et anxieux que celle des enfants contrôles. Des difficultés d’apprentissage étaient plus souvent rapportées chez les pères d’enfants avec un TDAH. Par ailleurs, l’isolement social et les accidents de la route étaient davantage présents chez les mères d’enfants avec un TDAH. Ces dernières souffraient plus de dépression et de trouble anxieux et prenaient davantage de médicaments que les mères contrôles. Conclusion: L’étude de facteurs de risque révèle un lien entre les parents et les enfants, spécifiquement la présence de dépression parmi les mères d’enfants avec un TDAH et de difficultés d’apprentissage chez les pères, suggérant une composante familiale dans le trouble. La sous-représentation du TDAH chez les pères d’enfants avec un TDAH est discutée. PMID:23133459

Feedback and efficient behavior

PubMed Central

2017-01-01

Feedback is an effective tool for promoting efficient behavior: it enhances individuals’ awareness of choice consequences in complex settings. Our study aims to isolate the mechanisms underlying the effects of feedback on achieving efficient behavior in a controlled environment. We design a laboratory experiment in which individuals are not aware of the consequences of different alternatives and, thus, cannot easily identify the efficient ones. We introduce feedback as a mechanism to enhance the awareness of consequences and to stimulate exploration and search for efficient alternatives. We assess the efficacy of three different types of intervention: provision of social information, manipulation of the frequency, and framing of feedback. We find that feedback is most effective when it is framed in terms of losses, that it reduces efficiency when it includes information about inefficient peers’ behavior, and that a lower frequency of feedback does not disrupt efficiency. By quantifying the effect of different types of feedback, our study suggests useful insights for policymakers. PMID:28430787

Algorithmes de couplage RANS et ecoulement potentiel

NASA Astrophysics Data System (ADS)

Gallay, Sylvain

Dans le processus de developpement d'avion, la solution retenue doit satisfaire de nombreux criteres dans de nombreux domaines, comme par exemple le domaine de la structure, de l'aerodynamique, de la stabilite et controle, de la performance ou encore de la securite, tout en respectant des echeanciers precis et minimisant les couts. Les geometries candidates sont nombreuses dans les premieres etapes de definition du produit et de design preliminaire, et des environnements d'optimisations multidisciplinaires sont developpes par les differentes industries aeronautiques. Differentes methodes impliquant differents niveaux de modelisations sont necessaires pour les differentes phases de developpement du projet. Lors des phases de definition et de design preliminaires, des methodes rapides sont necessaires afin d'etudier les candidats efficacement. Le developpement de methodes ameliorant la precision des methodes existantes tout en gardant un cout de calcul faible permet d'obtenir un niveau de fidelite plus eleve dans les premieres phases de developpement du projet et ainsi grandement diminuer les risques associes. Dans le domaine de l'aerodynamisme, les developpements des algorithmes de couplage visqueux/non visqueux permettent d'ameliorer les methodes de calcul lineaires non visqueuses en methodes non lineaires prenant en compte les effets visqueux. Ces methodes permettent ainsi de caracteriser l'ecoulement visqueux sur les configurations et predire entre autre les mecanismes de decrochage ou encore la position des ondes de chocs sur les surfaces portantes. Cette these se focalise sur le couplage entre une methode d'ecoulement potentiel tridimensionnelle et des donnees de section bidimensionnelles visqueuses. Les methodes existantes sont implementees et leurs limites identifiees. Une methode originale est ensuite developpee et validee. Les resultats sur une aile elliptique demontrent la capacite de l'algorithme a de grands angles d'attaques et dans la region post-decrochage. L'algorithme de couplage a ete compare a des donnees de plus haute fidelite sur des configurations issues de la litterature. Un modele de fuselage base sur des relations empiriques et des simulations RANS a ete teste et valide. Les coefficients de portance, de trainee et de moment de tangage ainsi que les coefficients de pression extraits le long de l'envergure ont montre un bon accord avec les donnees de soufflerie et les modeles RANS pour des configurations transsoniques. Une configuration a geometrie hypersustentatoire a permis d'etudier la modelisation des surfaces hypersustentees de la methode d'ecoulement potentiel, demontrant que la cambrure peut etre prise en compte uniquement dans les donnees visqueuses.

Feedback is the breakfast of champions: the significance of self-controlled formal feedback for autonomous task engagement.

PubMed

Meng, Liang; Yang, Zijing

2018-01-03

With the aim of examining the positive effect of the formal feedback mechanism itself beyond its informational aspect, we engaged participants in the stopwatch task and recorded their electroencephalogram throughout the experiment. This task requires a button press to stop the watch within a given time interval, the completion of which is simultaneously accompanied by adequate information on task performance. In the self-controlled feedback mode, participants could freely choose whether to request formal feedback after completing the task. In another mode, additional feedback was not provided. The 'non-choice' cue was found to elicit a more negative cue-elicited feedback negativity compared with 'choice', suggesting that the opportunity to solicit formal feedback was perceived as more desirable. In addition, a more enhanced stimulus-preceding negativity was observed prior to the task initiation cue in the self-controlled feedback condition, indicating that participants paid more sustained anticipatory attention during task preparation. Taken together, these electrophysiological results suggested an inherent reward within the formal feedback mechanism itself and the significance of self-controlled formal feedback for autonomous task engagement.

Evaluation des prescriptions antibiotiques au service des urgences de l’Hôpital Militaire d’Instruction Mohammed V (HMIMV)

PubMed Central

Elbouti, Anass; Rafai, Mostafa; Chouaib, Naoufal; Jidane, Said; Belkouch, Ahmed; Bakkali, Hicham; Belyamani, Lahcen

2016-01-01

Cette étude à pour objectifs de décrire les pratiques des prescriptions, évaluer leur pertinence et leur conformité aux règles d’utilisations et étudier les facteurs susceptibles de les influencer. Il s’agit d’une étude transversale d’évaluation des prescriptions antibiotiques portant sur 105 patients réalisée au service des urgences médico-chirurgicales de l’H.M.I.Med V de Rabat sur une période d’un mois. Le recueil des données était fait à l’aide d’un questionnaire rapportant les données démographiques et anamnestiques, les antécédents, la notion d’allergie, les données spécifiques de l’examen clinique, les données para cliniques, la prescription détaillée de l’antibiotique. Les données récoltées ont été ensuite évaluées par un médecin référent, chargé d’indiquer les éventuelles erreurs de traitement. Parmi les infections ayant motivé la prescription des antibiotiques, les affections des systèmes respiratoires et urinaires étaient au premier rang, les familles d’antibiotiques les plus couramment employées sont les pénicillines, les quinolones et les céphalosporines. 74 prescriptions soit (70,5%) étaient à la fois pertinentes et conformes contre 9 prescriptions soit (8,6%) justifiées mais non pertinentes et 6 prescriptions soit (5,7%) étaient jugées injustifiées par le médecin référent par absence d’infection. Les évaluations des pratiques médicales sont rarement menées dans les établissements de santé; c’est dans ce cadre que nous avons voulu nous inscrire en produisant cette étude afin d’améliorer la pertinence de nos prescriptions antibiotiques et d’optimiser leur conformité aux différentes recommandations. PMID:28292124

La prévention des blessures causées par les véhicules tout-terrains

PubMed Central

Yanchar, Natalie L

2012-01-01

RÉSUMÉ Les véhicules tout-terrains (VTT) sont largement utilisés au Canada dans le cadre des loisirs, du transport et du travail, tel que l’agriculture. En qualité de véhicules automobiles, ils peuvent être particulièrement dangereux lorsqu’ils sont utilisés par des enfants et des jeunes adolescents qui ne possèdent pas les connaissances, la taille physique, la force et les compétences cognitives et motrices nécessaires pour les conduire en toute sécurité. La magnitude du risque de blessures pour les jeunes conducteurs est exposée de manière explicite dans les avertissements figurant dans le manuel du conducteur et sur les étiquettes des modèles les plus récents. Elle est également et démontrée par le nombre important d’hospitalisations et de décès pédiatriques attribuables à des traumatismes liés aux VTT. Cependant, le port du casque est loin d’être universel chez les jeunes conducteurs, et les comportements de conduite non sécuritaires demeurent courants, tels que la conduite sans supervision ou avec des passagers. Malgré les avertissements de l’industrie et l’éducation publique qui font ressortir l’importance de comportements sécuritaires et les risques de graves blessures chez les enfants et les adolescents, on continue de recenser des blessures et des décès liés aux VTT. Tant que des mesures n’auront pas été prises pour réduire ces blessures de manière substantielle et efficace, il est essentiel de limiter la conduite par des jeunes, notamment ceux de moins de 16 ans, afin de réduire le fardeau des traumatismes liés aux VTT chez les enfants et les adolescents. Le présent document remplace le document de principes de la Société canadienne de pédiatrie publié en 2004.

Approche en soins primaires pour les problèmes de consommation de cannabis

PubMed Central

Turner, Suzanne D.; Spithoff, Sheryl; Kahan, Meldon

2014-01-01

Résumé Objectif Étudier les caractéristiques et complications cliniques de la consommation à risque de cannabis et du trouble de consommation de cannabis, et présenter un protocole en cabinet pour le dépistage, l’identification et la prise en charge de ces problèmes. Sources des données Une recherche des essais contrôlés, des études d’observation et des révisions sur l’usage de cannabis par les adolescents et les jeunes adultes; les méfaits psychiatriques et médicaux liés au cannabis; le trouble de consommation de cannabis et son traitement; et les lignes directrices sur la consommation à faible risque de cannabis a été effectuée dans PubMed. Message principal Les médecins doivent questionner tous leurs patients quant à leur usage de cannabis. Ils doivent questionner plus souvent les adolescents et jeunes adultes de même que les personnes qui présentent un risque élevé de problèmes liés au cannabis (qui ont un trouble psychiatrique ou de consommation de drogue concomitant). Les problèmes pouvant être causés par le cannabis, comme les troubles de l’humeur, la psychose et les symptômes respiratoires, devraient susciter des questions sur la consommation de cannabis. Aux patients qui rapportent un usage de cannabis, les médecins devraient poser des questions sur la fréquence et la quantité consommée, la présence de symptômes de tolérance ou de sevrage, les tentatives de réduire leur consommation et la présence de problèmes liés au cannabis. Les usagers à faible risque fument, inhalent ou ingèrent le cannabis occasionnellement sans aucun signe de dysfonctionnement scolaire, professionnel ou social; les personnes dont l’usage est problématique consomment tous les jours ou presque tous les jours, ont de la difficulté à réduire leur consommation et leur fonctionnement scolaire, professionnel et social est perturbé. Les médecins devraient offrir à tous les patients dont l’usage est problématique des conseils et un bref counseling, en insistant sur les effets du cannabis sur la santé et en visant l’abstinence (certains groupes à risque élevé devraient s’abstenir complètement de consommer du cannabis) ou la réduction de la consommation, et ils doivent fournir des stratégies pratiques de réduction de la consommation. Les techniques d’entrevue motivationnelle doivent faire partie des séances de counseling. Les médecins devraient aiguiller les patients qui sont incapables de réduire leur consommation ou qui présentent des problèmes liés à leur usage de cannabis vers des soins spécialisés, tout en veillant à ce qu’ils demeurent en contact avec leur généraliste. De plus, les médecins devraient donner à tous les usagers de cannabis de l’information sur la consommation à faible risque. Conclusion Les médecins devraient effectuer au moins une fois chez tous leurs patients de leur pratique un test de dépistage de l’usage de cannabis, particulièrement chez les patients qui présentent des problèmes pouvant être causés par le cannabis. Les tests de dépistage doivent être plus fréquents chez les personnes à risque, soit au moins tous les ans. Il faut savoir distinguer la consommation à faible risque de l’usage problématique. Les patients dont l’usage est problématique doivent recevoir de brèves séances de counseling et ces patients doivent être aiguillés vers un spécialiste s’ils sont incapables de réduire leur consommation ou d’y mettre un terme.

Perceptions des jeunes victimes de violence sexuelle au sein de leurs relations amoureuses sur leur pire expérience

PubMed Central

Van Camp, Tinneke; Hébert, Martine; Fernet, Mylène; Blais, Martin; Lavoie, Francine

2016-01-01

Cette étude explore les pires expériences vécues dans les relations amoureuses de jeunes qui ont rapporté avoir vécu de la violence sexuelle dans une relation de couple récente. Quelles sont les situations perçues comme étant les plus difficiles par les jeunes et est-ce que celles-ci se limitent à des incidents violents? Le questionnaire sur les parcours amoureux des jeunes (PAJ) a été complété par des jeunes Québécois âgés de 14 à 18 ans. Au total, plus de 600 participants ont rapporté au moins un épisode de violence sexuelle (souvent en combinaison avec d’autres formes de violence). Nous présentons les résultats de l’analyse qualitative inductive fondée sur une question ouverte concernant la pire expérience vécue. Les observations suggèrent que, en plus des expériences de violence, les difficultés relationnelles, les ruptures amoureuses et les sentiments amoureux non réciproques sont des situations particulièrement difficiles selon les propos des jeunes. Ces différents enjeux vécus par les jeunes devraient être pris en considération dans l’offre de services d’intervention à leur intention. PMID:28191266

Distorted retrospective eyewitness reports as functions of feedback and delay.

PubMed

Wells, Gary L; Olson, Elizabeth A; Charman, Steve D

2003-03-01

Participant-witnesses viewed a crime video and attempted to identify the culprit from a culprit-absent lineup. The 253 mistaken-identification eyewitnesses were randomly given confirming, disconfirming, or no feedback regarding their identifications. Feedback was immediate or delayed 48 hr, and measures were immediate or delayed 48 hr. Confirming, but not disconfirming, feedback led to distortions of eyewitnesses' recalled confidence, amount of attention paid during witnessing, goodness of view, ability to make out facial details, length of time to identification, and other measures related to the witnessing experience. Unexpectedly, neither delaying the measures nor delaying feedback for 48 hr moderated these effects. The results underscore the need for double-blind lineups and neutral assessments of eyewitnesses' certainty and other judgments prior to feedback.

Cohesion in Military and Aviation Psychology: An Annotated Bibliography and Suggestions for US Army Aviation

DTIC Science & Technology

2005-06-01

serve a significant influence upon perceptions. Strategies for mitigating the detrimental effects of racism and sexism are suggested. Leaders need to...Hedlund, J. (1998). Extending the multilevel theory of team decision making: Effects of feedback and experience in hierarchical teams. Academy of...Colquitt, J.A., & Hedlund, J. (1998). Extending the multilevel theory of team decision making: Effects of feedback and experience in hierarchical

Operating experience feedback report: New plants, Commercial power reactors

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

Dennig, R.L.; O'Reilly, P.D.

1987-07-01

This report documents a detailed review of the cause of unplanned events during the early months of licensed operation for plants licensed between March 1983 and April 1986. The major lessons and corrective actions that appear to have the greatest potential for improving the effectiveness of plant startups are provided for consideration through the operating experience feedback programs and activities of the industry and the NRC staff.

Validation de modeles d'eclairement incident a la surface de l'eau en Arctique

NASA Astrophysics Data System (ADS)

Julien, Laliberte

Dans ce memoire, deux methodes d'estimation d'eclairement incident a la surface de l'Arctique sont evaluees. Une base de donnees in situ a ete constituee a partir de 16 campagnes oceanographiques en Arctique. Pour les dates ou l'eclairement est mesure, les estimations d'eclairement journalier incident a la surface obtenues a partir des satellites de la couleur de l'eau (Frouin et al. 2003) et a partir des satellites meteorologiques (Belanger et al. 2013) sont produites. De meme, un exercise de comparaison entre les estimations satellitaires est produit pour l'annee 2004 sur tout le territoire Arctique. La comparaison entre les donnees observees et les donnees estimees a partir des satellites meteorologiques donnent un biais de 6% et une quadratique moyenne 33%. La comparaison entre les observations et les satellites de la couleur de l'eau donnent un biais de 2% et 20%. Finalement, la difference moyenne entre les estimations des 2 methodes d'estimation satellitaires pour tout l'Arctique pour l'annee 2004 est de 0,29 Einstein/m2/jour avec un ecart-type de 6,78 Einstein/m2/jour. Les resultats montrent entre autres que la methode qui utilise les satellites de la couleur de l'eau est plus precise pour estimer l'eclairement sur une petite superficie puisqu'elle rend mieux les variations locales dans l'eclairement. La methode qui utilise les satellites meteorologique est plus precise pour estimer l'eclairement sur une grande superficie, puisqu'elle est moins restreinte dans les conditions qui permettent de fournir une estimation. Ainsi, la methode qui utilise les satellites meteorologiques montre qu'un eclairement annuel de l'Arctique de 38% n'est pas prise en compte par les satellites de la couleur de l'eau.

Shifty: A Weight-Shifting Dynamic Passive Haptic Proxy to Enhance Object Perception in Virtual Reality.

PubMed

Zenner, Andre; Kruger, Antonio

2017-04-01

We define the concept of Dynamic Passive Haptic Feedback (DPHF) for virtual reality by introducing the weight-shifting physical DPHF proxy object Shifty. This concept combines actuators known from active haptics and physical proxies known from passive haptics to construct proxies that automatically adapt their passive haptic feedback. We describe the concept behind our ungrounded weight-shifting DPHF proxy Shifty and the implementation of our prototype. We then investigate how Shifty can, by automatically changing its internal weight distribution, enhance the user's perception of virtual objects interacted with in two experiments. In a first experiment, we show that Shifty can enhance the perception of virtual objects changing in shape, especially in length and thickness. Here, Shifty was shown to increase the user's fun and perceived realism significantly, compared to an equivalent passive haptic proxy. In a second experiment, Shifty is used to pick up virtual objects of different virtual weights. The results show that Shifty enhances the perception of weight and thus the perceived realism by adapting its kinesthetic feedback to the picked-up virtual object. In the same experiment, we additionally show that specific combinations of haptic, visual and auditory feedback during the pick-up interaction help to compensate for visual-haptic mismatch perceived during the shifting process.

Boosting the Motor Outcome of the Untrained Hand by Action Observation: Mirror Visual Feedback, Video Therapy, or Both Combined-What Is More Effective?

PubMed

Bähr, Florian; Ritter, Alexander; Seidel, Gundula; Puta, Christian; Gabriel, Holger H W; Hamzei, Farsin

2018-01-01

Action observation (AO) allows access to a network that processes visuomotor and sensorimotor inputs and is believed to be involved in observational learning of motor skills. We conducted three consecutive experiments to examine the boosting effect of AO on the motor outcome of the untrained hand by either mirror visual feedback (MVF), video therapy (VT), or a combination of both. In the first experiment, healthy participants trained either with MVF or without mirror feedback while in the second experiment, participants either trained with VT or observed animal videos. In the third experiment, participants first observed video clips that were followed by either training with MVF or training without mirror feedback. The outcomes for the untrained hand were quantified by scores from five motor tasks. The results demonstrated that MVF and VT significantly increase the motor performance of the untrained hand by the use of AO. We found that MVF was the most effective approach to increase the performance of the target effector. On the contrary, the combination of MVF and VT turns out to be less effective looking from clinical perspective. The gathered results suggest that action-related motor competence with the untrained hand is acquired by both mirror-based and video-based AO.

Boosting the Motor Outcome of the Untrained Hand by Action Observation: Mirror Visual Feedback, Video Therapy, or Both Combined—What Is More Effective?

PubMed Central

Ritter, Alexander; Seidel, Gundula; Puta, Christian; Gabriel, Holger H. W.; Hamzei, Farsin

2018-01-01

Action observation (AO) allows access to a network that processes visuomotor and sensorimotor inputs and is believed to be involved in observational learning of motor skills. We conducted three consecutive experiments to examine the boosting effect of AO on the motor outcome of the untrained hand by either mirror visual feedback (MVF), video therapy (VT), or a combination of both. In the first experiment, healthy participants trained either with MVF or without mirror feedback while in the second experiment, participants either trained with VT or observed animal videos. In the third experiment, participants first observed video clips that were followed by either training with MVF or training without mirror feedback. The outcomes for the untrained hand were quantified by scores from five motor tasks. The results demonstrated that MVF and VT significantly increase the motor performance of the untrained hand by the use of AO. We found that MVF was the most effective approach to increase the performance of the target effector. On the contrary, the combination of MVF and VT turns out to be less effective looking from clinical perspective. The gathered results suggest that action-related motor competence with the untrained hand is acquired by both mirror-based and video-based AO. PMID:29849570

Testing Quick Response (QR) Codes as an Innovation to Improve Feedback Among Geographically-Separated Clerkship Sites.

PubMed

Snyder, Matthew J; Nguyen, Dana R; Womack, Jasmyne J; Bunt, Christopher W; Westerfield, Katie L; Bell, Adriane E; Ledford, Christy J W

2018-03-01

Collection of feedback regarding medical student clinical experiences for formative or summative purposes remains a challenge across clinical settings. The purpose of this study was to determine whether the use of a quick response (QR) code-linked online feedback form improves the frequency and efficiency of rater feedback. In 2016, we compared paper-based feedback forms, an online feedback form, and a QR code-linked online feedback form at 15 family medicine clerkship sites across the United States. Outcome measures included usability, number of feedback submissions per student, number of unique raters providing feedback, and timeliness of feedback provided to the clerkship director. The feedback method was significantly associated with usability, with QR code scoring the highest, and paper second. Accessing feedback via QR code was associated with the shortest time to prepare feedback. Across four rotations, separate repeated measures analyses of variance showed no effect of feedback system on the number of submissions per student or the number of unique raters. The results of this study demonstrate that preceptors in the family medicine clerkship rate QR code-linked feedback as a high usability platform. Additionally, this platform resulted in faster form completion than paper or online forms. An overarching finding of this study is that feedback forms must be portable and easily accessible. Potential implementation barriers and the social norm for providing feedback in this manner need to be considered.

Déprescription des antihyperglycémiants chez les personnes âgées

PubMed Central

Farrell, Barbara; Black, Cody; Thompson, Wade; McCarthy, Lisa; Rojas-Fernandez, Carlos; Lochnan, Heather; Shamji, Salima; Upshur, Ross; Bouchard, Manon; Welch, Vivian

2017-01-01

Résumé Objectif Formuler des lignes directrices fondées sur les données probantes afin d’aider les cliniciens à décider du moment et de la façon sécuritaire de réduire la dose des antihyperglycémiants, de mettre fin au traitement ou de passer à un autre agent chez les personnes âgées. Méthodes Nous nous sommes concentrés sur les données les plus probantes disponibles et avons cherché à obtenir les commentaires des professionnels de première ligne durant le processus de rédaction, de révision et d’adoption des lignes directrices. L’équipe était formée de 7 professionnels de la santé (2 médecins de famille, 3 pharmaciens, 1 infirmière praticienne et 1 endocrinologue) et d’une spécialiste de la méthodologie; les membres ont divulgué tout conflit d’intérêts. Nous avons eu recours à un processus rigoureux, y compris l’approche GRADE (Grading of Recommendations Assessment, Development and Evaluation) pour formuler les lignes directrices. Nous avons effectué une revue systématique dans le but d’évaluer les données probantes indiquant les bienfaits et les torts liés à la déprescription des antihyperglycémiants. Nous avons révisé les revues des torts liés à la poursuite du traitement antihyperglycémiant, et effectué des synthèses narratives des préférences des patients et des répercussions sur les ressources. Ces synthèses et évaluations de la qualité des données selon l’approche GRADE ont servi à formuler les recommandations. L’équipe a peaufiné le texte sur le contenu et les recommandations des lignes directrices par consensus et a synthétisé les considérations cliniques afin de répondre aux questions courantes des cliniciens de première ligne. Une version préliminaire des lignes directrices a été distribuée aux cliniciens et aux intervenants aux fins d’examen, et des révisions ont été apportées au texte à chaque étape. Un algorithme d’appui décisionnel a été conçu pour accompagner les lignes directrices. Recommandations Nous recommandons de déprescrire les antihyperglycémiants reconnus pour contribuer à l’hypoglycémie chez les personnes âgées à risque ou dans les situations où les antihyperglycémiants pourraient causer d’autres effets indésirables, et d’individualiser les cibles et de déprescrire en conséquence chez les personnes frêles, atteintes de démence ou dont l’espérance de vie est limitée. Conclusion Les présentes lignes directrices émettent des recommandations pratiques pour décider du moment et de la façon de déprescrire les antihyperglycémiants. Elles visent à contribuer au processus de décision conjointement avec le patient et non à le dicter. PMID:29138168

Motivational and metacognitive feedback in SQL-Tutor*

NASA Astrophysics Data System (ADS)

Hull, Alison; du Boulay, Benedict

2015-04-01

Motivation and metacognition are strongly intertwined, with learners high in self-efficacy more likely to use a variety of self-regulatory learning strategies, as well as to persist longer on challenging tasks. The aim of the research was to improve the learner's focus on the process and experience of problem-solving while using an Intelligent Tutoring System (ITS) and including motivational and metacognitive feedback based on the learner's past states and experiences. An existing ITS, SQL-Tutor, was used with first-year undergraduates studying a database module. The study used two versions of SQL-Tutor: the Control group used a base version providing domain feedback and the Study group used an extended version that also provided motivational and metacognitive feedback. This paper summarises the pre- and post-process results. Comparisons between groups showed some differing trends both in learning outcomes and behaviour in favour of the Study group.

Cessation of oscillations in a chemo-mechanical oscillator

NASA Astrophysics Data System (ADS)

Phogat, Richa; Tiwari, Ishant; Kumar, Pawan; Rivera, Marco; Parmananda, Punit

2018-06-01

In this paper, different methods for cessation of oscillations in a chemo-mechanical oscillator [mercury beating heart (MBH)] are presented. The first set of experiments were carried out on a single MBH oscillator. To achieve cessation of oscillations, two protocols, namely, inverted feedback and delayed feedback were employed. In the second set of experiments, two quasi-identical MBH oscillators are considered. They are first synchronized via a bidirectional attractive coupling. These two synchronized oscillators are thereafter coupled with a unidirectional repulsive coupling and the system dynamics were observed. Subsequently, in the next protocol, the effect of a unidirectional delay coupling on the two synchronized oscillators was explored. The cessation of oscillations in all the above experimental setups was observed as the feedback/coupling was switched on at a suitable strength. Oscillatory dynamics of the system were restored when the feedback/coupling was switched off.

Comparing the Degree of Land-Atmosphere Interaction in Four Atmospheric General Circulation Models

NASA Technical Reports Server (NTRS)

Koster, Randal D.; Dirmeyer, Paul A.; Hahmann, Andrea N.; Ijpelaar, Ruben; Tyahla, Lori; Cox, Peter; Suarez, Max J.; Houser, Paul R. (Technical Monitor)

2001-01-01

Land-atmosphere feedback, by which (for example) precipitation-induced moisture anomalies at the land surface affect the overlying atmosphere and thereby the subsequent generation of precipitation, has been examined and quantified with many atmospheric general circulation models (AGCMs). Generally missing from such studies, however, is an indication of the extent to which the simulated feedback strength is model dependent. Four modeling groups have recently performed a highly controlled numerical experiment that allows an objective inter-model comparison of land-atmosphere feedback strength. The experiment essentially consists of an ensemble of simulations in which each member simulation artificially maintains the same time series of surface prognostic variables. Differences in atmospheric behavior between the ensemble members then indicates the degree to which the state of the land surface controls atmospheric processes in that model. A comparison of the four sets of experimental results shows that feedback strength does indeed vary significantly between the AGCMs.

Factors Influencing Oral Corrective Feedback Provision in the Spanish Foreign Language Classroom: Investigating Instructor Native/Nonnative Speaker Status, SLA Education, & Teaching Experience

ERIC Educational Resources Information Center

Gurzynski-Weiss, Laura

2010-01-01

The role of interactional feedback has been a critical area of second language acquisition (SLA) research for decades and while findings suggest interactional feedback can facilitate SLA, the extent of its influence can vary depending on a number of factors, including the native language of those involved in communication. Although studies have…

Clustering in Cell Cycle Dynamics with General Response/Signaling Feedback

PubMed Central

Young, Todd R.; Fernandez, Bastien; Buckalew, Richard; Moses, Gregory; Boczko, Erik M.

2011-01-01

Motivated by experimental and theoretical work on autonomous oscillations in yeast, we analyze ordinary differential equations models of large populations of cells with cell-cycle dependent feedback. We assume a particular type of feedback that we call Responsive/Signaling (RS), but do not specify a functional form of the feedback. We study the dynamics and emergent behaviour of solutions, particularly temporal clustering and stability of clustered solutions. We establish the existence of certain periodic clustered solutions as well as “uniform” solutions and add to the evidence that cell-cycle dependent feedback robustly leads to cell-cycle clustering. We highlight the fundamental differences in dynamics between systems with negative and positive feedback. For positive feedback systems the most important mechanism seems to be the stability of individual isolated clusters. On the other hand we find that in negative feedback systems, clusters must interact with each other to reinforce coherence. We conclude from various details of the mathematical analysis that negative feedback is most consistent with observations in yeast experiments. PMID:22001733

Révision systématique des effets de la fréquence des repas en famille sur les résultats psychosociaux chez les jeunes

PubMed Central

Harrison, Megan E.; Norris, Mark L.; Obeid, Nicole; Fu, Maeghan; Weinstangel, Hannah; Sampson, Margaret

2015-01-01

Résumé Objectif Effectuer une révision systématique des effets de repas en famille fréquents sur les résultats psychosociaux chez les enfants et les adolescents et examiner s’il existe des différences dans les résultats selon le sexe. Sources des données Des études ont été cernées à la suite d’une recherche dans MEDLINE (de 1948 à la dernière semaine de juin 2011) et dans PsycINFO (de 1806 à la première semaine de juillet 2011) à l’aide de l’interface Ovide. Les expressions et mots clés MeSH utilisés seuls ou en combinaisons étaient les suivants : family, meal, food intake, nutrition, diets, body weight, adolescent attitudes, eating behaviour, feeding behaviour et eating disorders. Les bibliographies des articles jugés pertinents ont aussi été passées en revus. Sélection des études La recherche initiale a produit 1783 articles. Pour être incluses dans l’analyse, les études devaient répondre aux critères suivants : être publiées en anglais dans une revue révisée par des pairs; porter sur des enfants ou des adolescents; traiter de l’influence des repas en famille sur les paramètres psychosociaux (p. ex. consommation de drogues et autres substances, troubles de l’alimentation, dépression) chez les enfants ou les adolescents; avoir une conception d’étude appropriée, notamment des méthodes statistiques acceptables pour l’analyse des paramètres. Quatorze articles satisfaisaient aux critères d’inclusion. Deux examinateurs indépendants ont étudié et analysé les articles. Synthèse Dans l’ensemble, les résultats font valoir que la fréquence des repas en famille est inversement proportionnelle aux troubles de l’alimentation, à la consommation d’alcool et de drogues, aux comportements violents, aux sentiments de dépression ou aux pensées suicidaires chez les adolescents. Il existe une relation positive entre de fréquents repas en famille, une bonne estime de soi et la réussite scolaire. Les études révèlent des différences considérables dans les résultats chez les enfants et adolescents masculins et féminins, les sujets féminins ayant des résultats plus positifs. Conclusion Cette révision systématique vient confirmer davantage qu’il convient de préconiser de fréquents repas en famille. Tous les professionnels de la santé devraient renseigner les familles concernant les bienfaits de prendre régulièrement ensemble des repas.

L’infection bactérienne chez le patient brûlé

PubMed Central

Le Floch, R.; Naux, E.; Arnould, J.F.

2015-01-01

Summary La mort d’un patient brûlé est le plus souvent causée par une infection, bactérienne dans la grande majorité des cas. La perte de la barrière cutanée, les dispositifs invasifs et l’immunodépression liée à la brûlure sont trois mécanismes concourant à la survenue de ces infections. Chez un patient inflammatoire, les signes infectieux généraux d’infection sont peu discriminants. Du fait de la gravité des infections chez ce patient, leur prévention est un paramètre essentiel de la prise en charge. En raison des particularités pharmacocinétiques des brûlés, les posologies d’antibiotiques doivent être adaptés et les dosages sanguins doivent être systématiques. A l’heure où les résistances deviennent préoccupantes, les recherches sur les thérapeutiques sur les alternatives thérapeutiques parmi lesquels les inhibiteurs de facteurs de virulence, les peptides antimicrobiens, les polyphénols, l’immunothérapie…) deviennent cruciales. L’une des possibilités thérapeutiques les plus prometteuses semble être la phagothérapie. PMID:27252607

The Astronomical Forcing of Climate Change: Forcings and Feedbacks

NASA Astrophysics Data System (ADS)

Erb, M. P.; Broccoli, A. J.; Clement, A. C.

2010-12-01

Understanding the role that orbital forcing played in driving climate change over the Pleistocene has been a matter of ongoing research. While it is undeniable that variations in Earth’s orbit result in changes in the seasonal and latitudinal distribution of insolation, the specifics of how this forcing leads to the climate changes seen in the paleo record are not fully understood. To research this further, climate simulations have been conducted with the GFDL CM2.1, a coupled atmosphere-ocean GCM. Two simulations represent the extremes of obliquity during the past 600 kyr and four others show key times in the precessional cycle. All non-orbital variables are set to preindustrial levels to isolate the effects of astronomical forcing alone. It is expected that feedbacks should play a large role in dictating climate change, so to investigate this, the so-called “kernel method” is used to calculate the lapse rate, water vapor, albedo, and cloud feedbacks. Preliminary results of these experiments confirm that feedbacks are important in explaining the nature and, in places, even the sign of climate response to orbital forcing. In the case of low obliquity, for instance, a combination of climate feedbacks lead to global cooling in spite of zero global-average top of atmosphere insolation change. Feedbacks will be analyzed in the obliquity and precession experiments so that the role of feedbacks in contributing to climate change may be better understood.

Experience in action: Moderating care in web-based patient feedback.

PubMed

Ziewitz, Malte

2017-02-01

What does it take to mobilise experiences of care and make them useful for improving services? This article draws on ethnographic fieldwork with a UK-based patient feedback website to develop a critical perspective on patient experience as a contingent accomplishment and a focal point for eliciting, provoking, and respecifying relations of accountability. Following a single posting from the moderation room back to the author and into the wards and offices of the hospital, I show how moderators, carers, and clinical staff respond to and act upon a seemingly stable experience. Drawing on recent work in science studies and ethnomethodology, I suggest that the work of 'capturing the patient experience' is not so much a matter of accurate reporting or incontestable opining, but an exercise in testing versions of reality through the ongoing respecification of objects, audiences, and identities. Attending to the mundane practices of moderating accounts of care highlights the work of ordering alongside technologies of evaluation - the largely invisible labour that sustains the possibility of public patient feedback in the first place. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nouvelle approche à la prise en charge des condylomes

PubMed Central

Lopaschuk, Catharine C.

2013-01-01

Résumé Objectif Faire le résumé des anciens et des nouveaux moyens de traitement des verrues génitales ou condylomes et déterminer comment les utiliser de manière appropriée. Sources des données Une recherche documentaire a été effectuée dans les bases de données suivantes: MEDLINE, PubMed, EMBASE, base de données des synthèses systématiques et registre central des études contrôlées de la Collaboration Cochrane (en anglais), ACP Journal Club et Trip. Les bibliographies des articles extraits ont aussi été examinées. Les études cliniques, les articles de révision qualitative, les rapports consensuels et les guides de pratique clinique ont été retenus. Message principal Les verrues symptomatiques sont présentes chez au moins 1 % des personnes âgées entre 15 et 49 ans et on estime que jusqu’à 50 % des gens sont infectés par le virus du papillome humain à un moment donné de leur vie. L’imiquimod et la podophyllotoxine sont 2 nouveaux traitements pour les verrues génitales externes qui sont moins douloureux et peuvent être appliqués par les patients à la maison. De plus, il a été démontré que le vaccin quadrivalent contre le virus du papillome humain est efficace pour prévenir les condylomes et le cancer du col. Les plus anciennes méthodes thérapeutiques ont aussi leur place dans certaines situations, comme les verrues intravaginales, urétrales, anales ou récalcitrantes ou encore pour les patientes enceintes. Conclusion Les nouveaux traitements des verrues génitales externes peuvent réduire la douleur causée par la thérapie et le nombre de visites au cabinet. Les autres méthodes thérapeutiques demeurent utiles dans certaines situations.

Effects of roadway configurations on near-road air quality and the implications on roadway designs

EPA Science Inventory

This paper presents an analysis of wind tunnel experiments of twelve different roadway configurations and modeling of these configurations using a Large-Eddy Simulation (LES) model, aiming at investigating how flow structures affect the impact of roadway features on near-road and...

Contributions to workload of rotational optical transformations

NASA Technical Reports Server (NTRS)

Atkinson, R. P.; Harrington, T. L.

1985-01-01

An investigation of visuomotor adaptation to optical rotation and optical inversion was conducted. Experiment 1 examined the visuomotor adaptability of subjects to an optically rotating visual world with a univariate repeated measures design. Experiment 1A tested one major prediction of a model of adaptation put forth by Welch who predicted that the aversive drive state that triggers adaptation would be habituated to fairly rapidly. Experiment 2 was conducted to investigate the role of motor activity in adaptation to optical rotation. Specifically, this experiment contrasted the reafference hypothesis and the proprioceptive change hypothesis. Experiment 3 examined the role of cognition, error-corrective feedback, and proprioceptive and/or reafferent feedback in visuomotor adaptation to optical inversion. Implications for research and implications for practice were suggested for all experiments.

Eye movements in interception with delayed visual feedback.

PubMed

Cámara, Clara; de la Malla, Cristina; López-Moliner, Joan; Brenner, Eli

2018-07-01

The increased reliance on electronic devices such as smartphones in our everyday life exposes us to various delays between our actions and their consequences. Whereas it is known that people can adapt to such delays, the mechanisms underlying such adaptation remain unclear. To better understand these mechanisms, the current study explored the role of eye movements in interception with delayed visual feedback. In two experiments, eye movements were recorded as participants tried to intercept a moving target with their unseen finger while receiving delayed visual feedback about their own movement. In Experiment 1, the target randomly moved in one of two different directions at one of two different velocities. The delay between the participant's finger movement and movement of the cursor that provided feedback about the finger movements was gradually increased. Despite the delay, participants followed the target with their gaze. They were quite successful at hitting the target with the cursor. Thus, they moved their finger to a position that was ahead of where they were looking. Removing the feedback showed that participants had adapted to the delay. In Experiment 2, the target always moved in the same direction and at the same velocity, while the cursor's delay varied across trials. Participants still always directed their gaze at the target. They adjusted their movement to the delay on each trial, often succeeding to intercept the target with the cursor. Since their gaze was always directed at the target, and they could not know the delay until the cursor started moving, participants must have been using peripheral vision of the delayed cursor to guide it to the target. Thus, people deal with delays by directing their gaze at the target and using both experience from previous trials (Experiment 1) and peripheral visual information (Experiment 2) to guide their finger in a way that will make the cursor hit the target.

Vibrotactile Feedback for Brain-Computer Interface Operation

PubMed Central

Cincotti, Febo; Kauhanen, Laura; Aloise, Fabio; Palomäki, Tapio; Caporusso, Nicholas; Jylänki, Pasi; Mattia, Donatella; Babiloni, Fabio; Vanacker, Gerolf; Nuttin, Marnix; Marciani, Maria Grazia; Millán, José del R.

2007-01-01

To be correctly mastered, brain-computer interfaces (BCIs) need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (including 3 with spinal cord injury), we compared vibrotactile and visual feedback, addressing: (I) the feasibility of subjects' training to master their EEG rhythms using tactile feedback; (II) the compatibility of this form of feedback in presence of a visual distracter; (III) the performance in presence of a complex visual task on the same (visual) or different (tactile) sensory channel. The stimulation protocol we developed supports a general usage of the tactors; preliminary experimentations. All studies indicated that the vibrotactile channel can function as a valuable feedback modality with reliability comparable to the classical visual feedback. Advantages of using a vibrotactile feedback emerged when the visual channel was highly loaded by a complex task. In all experiments, vibrotactile feedback felt, after some training, more natural for both controls and SCI users. PMID:18354734

Mitigating driver distraction with retrospective and concurrent feedback.

PubMed

Donmez, Birsen; Boyle, Linda Ng; Lee, John D

2008-03-01

An experiment was conducted to assess the effects of retrospective and combined retrospective and concurrent feedback on driver performance and engagement in distracting activities. A previous study conducted by the authors showed that concurrent (or real time) feedback can help drivers better modulate their distracting activities. However, research also shows that concurrent feedback can pose additional distractions due to the limited time and resources available during driving. Retrospective feedback, which is presented at the end of a trip (i.e., post-drive), can include additional information on safety critical situations during a trip and help the driver learn safe driving habits. A driving simulator study was conducted with 48 participants and 3 conditions: retrospective feedback, combined feedback (both retrospective and concurrent), and no feedback (baseline case). The feedback conditions (retrospective and combined) resulted in faster response to lead vehicle braking events as depicted by shorter accelerator release times. Moreover, combined feedback also resulted in longer glances to the road. The results suggest that both feedback types have potential to improve immediate driving performance and driver engagement in distractions. Combined feedback holds the most promise for mitigating the effects of distraction from in-vehicle information systems.

The influence of teacher feedback on children's perceptions of student-teacher relationships.

PubMed

Skipper, Yvonne; Douglas, Karen

2015-09-01

Teachers can deliver feedback using person ('you are clever') or process terms ('you worked hard'). Person feedback can lead to negative academic outcomes, but there is little experimental research examining the impact of feedback on children's perceptions of the student-teacher relationship. We examined the effects of person, process, and no feedback on children's perceptions of their relationship with a (fictional) teacher following success and failure. Participants were British children (145 aged 9-11 in experiment 1 and 98 aged 7-11 in experiment 2). In experiment 1, participants read three scenarios where they succeeded and received one of two types of praise (person or process) or no praise. Participants then read two scenarios where they failed. In experiment 2, participants read that they had failed in three tasks and received one of two types of criticism (person or process) or no criticism. Participants then read two scenarios where they succeeded. They rated how much they liked the teacher and how much they felt that the teacher liked them. Children felt more positive about the student-teacher relationship following success than failure. Type of praise did not influence perceptions of the student-teacher relationship following success or failure. However, person criticism led children to view the student-teacher relationship more negatively following failure and maintain this negative view following the first success. Success appears to be important for developing positive student-teacher relationships. In response to failure, teachers could avoid person criticism which may negatively influence the student-teacher relationship. © 2015 The British Psychological Society.

NCEA Scientists - Past and Present

EPA Science Inventory

Les Grant

Dr. Les Grant, Director of EPA's National Center for Environmental Assessment's Research Triangle Park Divisi...

L’évaluation et la prise en charge des enfants et des adolescents victimes d’une commotion liée à un sport

PubMed Central

Purcell, Laura K

2012-01-01

RÉSUMÉ Les commotions sont des blessures sportives fréquentes, et elles sont particulièrement courantes chez les enfants et les adolescents qui participent à des sports organisés ou à des activités récréatives. Les symptômes de commotion peuvent être subtils et négligés par les athlètes, les entraîneurs et les parents. Un enfant ou un adolescent qui est victime d’une commotion devrait être immédiatement retiré du jeu et être évalué par un médecin dans les plus brefs délais. Il devrait éviter les activités physiques et cognitives pour se remettre de la commotion. Une fois les symptômes complètement résorbés au repos, l’athlète peut suivre un protocole d’effort graduel, supervisé par un médecin, avant d’obtenir l’autorisation médicale de retourner au jeu. Il est essentiel que tous ceux qui participent aux activités sportives pour les enfants et les adolescents connaissent les signes et symptômes de commotion afin qu’on puisse poser un diagnostic exact et rapide et amorcer une évaluation et une prise en charge convenables. Le présent document de principes remplace celui qui a été publié en 2006.

La biogenèse des mélanosomes

PubMed Central

Delevoye, Cédric; Giordano, Francesca; van Niel, Guillaume; Raposo, Graça

2012-01-01

Les mélanocytes situés à la base de l’épiderme produisent des mélanosomes qui sont transférés aux kératinocytes pour assurer la pigmentation de l’épiderme et sa photoprotection contre les rayons ultraviolets. Les mélanosomes, organites apparentés aux lysosomes, sont le lieu de synthèse et de stockage d’un pigment, la mélanine. Leur formation dépend de protéines mélanosomales qui transitent par les voies de biosynthèse et d’endocytose et exploitent les mécanismes moléculaires du trafic intracellulaire. Les acteurs moléculaires impliqués dans le transport des protéines mélanosomales et la biogenèse des mélanosomes sont la cible de mutations dans des maladies génétiques accompagnées d’hypopigmentation comme l’albinisme et les maladies lysosomales. Les études menées sur les mélanocytes issus de souris modèles de ces maladies permettent de comprendre certaines des étapes-clés de la mélanogenèse ainsi que les dysfonctionnements associés à ces pathologies. De plus, décrypter la mélanogenèse facilite également la compréhension d’autres processus physiologiques, comme l’illustrent les similitudes inattendues avec l’amyloïdogenèse dans les maladies neurodégénératives. PMID:21382323

Les accidents du travail dans le transport urbain en commun de la ville province de Kinshasa, République Démocratique du Congo: une étude transversale descriptive

PubMed Central

Wangata, Jemima; Elenge, Myriam; De Brouwer, Christophe

2014-01-01

Introduction Le transport en commun urbain constitue un secteur où les travailleurs sont très exposés aux accidents du travail. Cette étude visait une description épidémiologique des accidents du travail dans le secteur informel du transport en commun à Kinshasa en vue d'apporter les pistes d'amélioration de la sécurité des travailleurs dans cette activité. Méthodes Un questionnaire sur les accidents du travail, administré en Décembre 2012 a permis d'explorer les tendances significatives entre les accidents et leurs circonstances, leurs facteurs associés, leurs conséquences au sein d'une population des travailleurs (n = 472) du transport en commun à Kinshasa. Résultats Durant les 12 derniers précédant l’étude 76.5% des travailleurs ont connu au moins un accident du travail, 54,8% ont connu un arrêt d'au moins 1jour. Les accidents liés à la circulation routière étaient plus important suivis des chutes. Les facteurs ayant montré des différences significatives étaient le travail sous l'influence de l'alcool et le port des équipements de protection individuelle. Les plaies (46,3%) et les contusions (39,4%) étaient les lésions les plus courantes. Les membres supérieurs (51,3%) et inférieurs (30,7%) étaient les plus atteints. 76,6% des travailleurs ont assumé seuls leur prise en charge médicale. Conclusion L'incidence des accidents du travail dans ce secteur est très élevée. La mise en place d'une politique de prévention et gestion de différents facteurs associés ainsi qu'un système de déclaration d'accidents est nécessaire dans ce secteur. Les patrons ainsi que les politiques devraient veiller à une prise en charge médicale correcte pour des travailleurs accidentés. PMID:25667703

Mesure de haute resolution de la fonction de distribution radiale du silicium amorphe pur

NASA Astrophysics Data System (ADS)

Laaziri, Khalid

1999-11-01

Cette these porte sur l'etude de la structure du silicium amorphe prepare par irradiation ionique. Elle presente des mesures de diffraction de rayons X sur de la poudre de silicium cristallin, du silicium amorphe relaxe et non relaxe, ainsi que tous les developpements mathematiques et physiques necessaires pour extraire la fonction de distribution radiale correspondant a chaque echantillon. Au Chapitre I, nous presentons une methode de fabrication de membranes minces de silicium amorphe pur. Il y a deux etapes majeures lors du processus de fabrication: l'implantation ionique, afin de creer une couche amorphe de plusieurs microns et l'attaque chimique, pour enlever le reste du materiau cristallin. Nous avons caracterise premierement les membranes de silicium amorphe par spectroscopie Raman pour verifier qu'il ne reste plus de trace de materiau cristallin dans les films amorphes. Une deuxieme caracterisation par detection de recul elastique (ERD-TOF) sur ces memes membranes a montre qu'il y a moins de 0.1% atomique de contaminants tels que l'oxygene, le carbone, et l'hydrogene. Au Chapitre II, nous proposons une nouvelle methode de correction de la contribution inelastique "Compton" des spectres de diffusion totale afin d'extraire les pics de diffusion elastique, responsable de la diffraction de Bragg. L'article presente tout d'abord une description simplifiee d'une theorie sur la diffusion inelastique dite "Impulse Approximation" (IA) qui permet de calculer des profils de Compton en fonction de l'energie et de l'angle de diffusion 2theta. Ces profils sont utilises comme fonction de lissage de la diffusion Compton experimentale. Pour lisser les pics de diffusion elastique, nous avons utilise une fonction pic de nature asymetrique. Aux Chapitre III, nous exposons de maniere detaillee les resultats des experiences de diffraction de rayons X sur les membranes de silicium amorphe et la poudre de silicium cristallin que nous avons preparees. Nous abordons aussi les differentes etapes experimentales, d'analyse ainsi que les methodes de determination et de filtrage des transformees de Fourier des donnees de diffraction. Une comparaison des fonctions de distribution radiale du silicium amorphe relaxe et non relaxe indique que la relaxation structurelle dans le silicium amorphe est probablement due en grande partie a une annihilation des defauts plutot qu'a une reorganisation atomique globale du reseau de silicium amorphe. La deduction de la coordination des pics correspondants au premiers voisins atomiques par lissage de fonctions gaussienne indique que la coordination du silicium amorphe relaxe est de 3.88, celle du non-relaxe est de 3.79, alors que la mesure de reference sur la poudre de silicium cristallin donne une valeur de 4 tel que prevu. La sous-coordination du silicium amorphe expliquerait pourquoi sa densite est inferieure a celle du silicium cristallin. (Abstract shortened by UMI.)

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

NASA Technical Reports Server (NTRS)

Bellan, Josette; Taskinoglu, Ezgi

2012-01-01

Currently, the modeling of supercritical-pressure flows through Large Eddy Simulation (LES) uses models derived for atmospheric-pressure flows. Those atmospheric-pressure flows do not exhibit the particularities of high densitygradient magnitude features observed both in experiments and simulations of supercritical-pressure flows in the case of two species mixing. To assess whether the current LES modeling is appropriate and if found not appropriate to propose higher-fidelity models, a LES a posteriori study has been conducted for a mixing layer that initially contains different species in the lower and upper streams, and where the initial pressure is larger than the critical pressure of either species. An initially-imposed vorticity perturbation promotes roll-up and a double pairing of four initial span-wise vortices into an ultimate vortex that reaches a transitional state. The LES equations consist of the differential conservation equations coupled with a real-gas equation of state, and the equation set uses transport properties depending on the thermodynamic variables. Unlike all LES models to date, the differential equations contain, additional to the subgrid scale (SGS) fluxes, a new SGS term that is a pressure correction in the momentum equation. This additional term results from filtering of Direct Numerical Simulation (DNS) equations, and represents the gradient of the difference between the filtered pressure and the pressure computed from the filtered flow field. A previous a priori analysis, using a DNS database for the same configuration, found this term to be of leading order in the momentum equation, a fact traced to the existence of high-densitygradient magnitude regions that populated the entire flow; in the study, models were proposed for the SGS fluxes as well as this new term. In the present study, the previously proposed constantcoefficient SGS-flux models of the a priori investigation are tested a posteriori in LES, devoid of or including, the SGS pressure correction term. The present pressure-correction model is different from, and more accurate as well as less computationally intensive than that of the a priori study. The constant-coefficient SGS-flux models encompass the Smagorinsky (SMC), in conjunction with the Yoshizawa (YO) model for the trace, the Gradient (GRC) and the Scale Similarity (SSC) models, all exercised with the a priori study constant coefficients calibrated at the transitional state. The LES comparison is performed with the filtered- and-coarsened (FC) DNS, which represents an ideal LES solution. Expectably, an LES model devoid of SGS terms is shown to be considerably inferior to models containing SGS effects. Among models containing SGS effects, those including the pressure-correction term are substantially superior to those devoid of it. The sensitivity of the predictions to the initial conditions and grid size are also investigated. Thus, it has been discovered that, additional to the atmospheric-pressure models currently used, a new model is necessary to simulate supercritical-pressure flows. This model depends on the thermodynamic characteristics of the chemical species involved.

Profil pressionnel de l’adolescent en milieu scolaire à Lubumbashi, République Démocratique du Congo

PubMed Central

Kakoma, Placide Kambola; Muyumba, Emmanuel Kiyana; Mukeng, Clarence Kaut; Musung, Jaques Mbaz; Kakisingi, Christian Ngama; Mukuku, Olivier; Nkulu, Dophra Ngoy

2018-01-01

Introduction L'objectif de cette étude était de donner le profil de la pression artérielle (PA) des adolescents âgés de 15 à 19 ans en milieu scolaire à Lubumbashi, République Démocratique du Congo. Méthodes il s'agit d'une étude transversale, portant sur les adolescents âgés de 15 à 19 ans au moyen d'un échantillonnage aléatoire des écoles secondaires de Lubumbashi durant les années scolaires 2013-2014, 2014-2015 et 2015-2016. Trois mesures de PA étaient effectuées le même jour. Résultats 1766 adolescents âgés de 15-19 ans ont été inclus parmi eux 995 étaient de sexe féminin et 771 garçons. Les garçons avaient significativement une pression artérielle systolique élevée que les filles dans les tranches d'âges de 17, 18 et 19 ans. La pression artérielle diastolique n'était pas différente statistiquement dans toutes les tranches d'âges dans les deux sexes. Par contre, dans les deux sexes, la pression artérielle systolique été en corrélation significative avec le poids, la taille, l'indice de masse corporelle, le tour de taille et la fréquence cardiaque. Quant à la pression artérielle diastolique, des corrélations significatives étaient retrouvées avec le poids et l'indice de masse corporelle chez les filles alors que la fréquence cardiaque était en corrélation significative dans les deux sexes. Discussion Au cours de notre étude, il était question de déterminer les valeurs moyennes de PA et sa corrélation avec les paramètres anthropométriques, la FC et le poids de naissance chez les adolescents d'âge compris entre 15 et 19 ans. Notre étude a révélé des valeurs moyennes de PAS chez les garçons qui étaient plus élevées que les filles statistiquement significatives dans les tranches d'âges de 17, 18 et 19 ans alors que les valeurs moyennes de PAD n'avait pas de différence statistiquement significative dans toutes les tranches d'âges dans les deux sexes. Harrabi et al. [16], dans leur étude incluant 1569 sujets âgés de 13 à 19 ans, avaient trouvé que les garçons de 16, 17 et 18 ans avaient des PAS élevées sans différence statistiquement significatives mais les différences statistiquement significatives étaient remarquées chez les filles de 13 et 14 ans concernant la PAD. Dans son étude chez les enfants, Forrester et al. [17] avaient rapporté une corrélation positive entre la PAS et l'âge chez les garçons et négative chez les filles. Cette corrélation négative trouvée entre la PAS et l'âge chez les filles pourrait être expliquée par les modifications hormonales liées à la puberté qui commencent plus tôt chez les filles que chez les garçons. Se référant à la littérature, la PA augmente avec la croissance en âge plus chez les garçons suite à l'augmentation de la masse musculaire pendant la puberté [18-20]. Notre étude a montré que la PAS était en corrélation significative avec le poids, la taille, l'IMC, le tour de taille et la FC dans les deux sexes. Ce constat est similaire à celui faite par l'étude de Harrabi et al. [16] qui rapportait que la PAS était en corrélation positive avec la taille (garçons: r = 0,33; p < 0,0001; filles: r = 0,08; p = 0,02), le poids (garçons: r = 0,47, p < 0,0001; filles: r = 0,35; p < 0,0001) et l'âge (r = 0,12; p < 0,0001). Quant à la PAD dans notre étude, les corrélations significatives positives étaient retrouvées avec le poids (r = 0,093; p = 0,003) et l'IMC (r = 0,079; p = 0,012) seulement chez les filles, alors que la FC était en corrélation significative positive chez les garçons (r = 0,168; p < 0,0001) mais non chez les filles (r = 0,12, p < 0,0001) [16]. Dans une étude similaire chez les adolescents réalisée par Sinaiko et al. [21], une corrélation a été trouvée entre le poids et la PAS chez les garçons (r = 0,167, p < 0,0001) et les filles (r = 0,112, p < 0,0001). L'effet de la taille et du poids sur la PA a déjà été démontré dans plusieurs études transversales antérieures sur les enfants concluant en une forte corrélation positive [22,23]. L'insuffisance de déclaration des naissances à l'état civil dans plusieurs pays en développement, conséquente au recours aux poids de naissance déclarés auprès des parents ou tuteurs, serait un biais dans la réalisation des résultats statistiquement comparables. Conclusion Malgré les faiblesses potentielles de la présente étude dans sa conception transversale et les mesures de la PA le même jour, les données pourraient aider les responsables de la santé à adopter une stratégie nationale de prévention de l'hypertension artérielle dans notre population. PMID:29875975

Numerical simulation of flow around the NREL S826 airfoil at moderate Reynolds number using delayed detached Eddy simulation (DDES)

NASA Astrophysics Data System (ADS)

Prytz, Erik R.; Huuse, Øyvind; Müller, Bernhard; Bartl, Jan; Sætran, Lars Roar

2017-07-01

Turbulent flow at Reynolds numbers 5 . 104 to 106 around the NREL S826 airfoil used for wind turbine blades is simulated using delayed detached eddy simulation (DDES). The 3D domain is built as a replica of the low speed wind tunnel at the Norwegian University of Science and Technology (NTNU) with the wind tunnel walls considered as slip walls. The subgrid turbulent kinetic energy is used to model the sub-grid scale in the large eddy simulation (LES) part of DDES. Different Reynoldsaveraged Navier-Stokes (RANS) models are tested in ANSYS Fluent. The realizable k - ∈ model as the RANS model in DDES is found to yield the best agreement of simulated pressure distributions with the experimental data both from NTNU and the Technical University of Denmark (DTU), the latter for a shorter spanwise domain. The present DDES results are in excellent agreement with LES results from DTU. Since DDES requires much fewer cells in the RANS region near the wing surface than LES, DDES is computationally much more efficient than LES. Whereas DDES is able to predict lift and drag in close agreement with experiment up to stall, pure 2D RANS simulations fail near stall. After testing different numerical settings, time step sizes and grids for DDES, a Reynolds number study is conducted. Near stall, separated flow structures, so-called stall cells, are observed in the DDES results.

Dermatoses gériatriques en hospitalisation dermatologique à Bamako (Mali)

PubMed Central

Fofana, Youssouf; Traoré, Bekaye; Faye, Ousmane; Dicko, Adama; Berthé, Siritio; Tall, Koureissi; Kéita, Lassine; Kéita, Somita

2016-01-01

Introduction Les pathologies cutanées du sujet âgé sont variées et constituent une véritable préoccupation pour les médecins en termes de diagnostic, de prise en charge et de suivi. Le but de ce travail était de décrire les motifs d’hospitalisation chez les sujets âgés hospitalisés dans le service de dermatologie du centre national d’appui à la lutte contre la maladie à Bamako. Méthodes Du 1er Janvier 2010 au 31 Décembre 2014, nous avons mené une étude transversale des cas de dermatoses gériatriques hospitalisées dans le service de dermatologie du centre national d’appui à la lutte contre la maladie. Sur un total de 398 patients hospitalisés, 76 malades âgés de 60 ans et plus avaient été inclus. Les données ont été saisies sur le logiciel Epidata 3.1 et analysées à l’aide du logiciel stata 14. Résultats La fréquence des pathologies cutanées chez les sujets âgés hospitalisés était de 19,10%. L’âge des malades variait de 60 à 95 ans avec une moyenne d’âge de 68,85 ans. Les malades se répartissaient en 29 hommes et 47 femmes soit un sex-ratio de 0,60. Les principales affections recensées étaient les dermohypodermites (44,74%), les dermatoses bulleuses auto-immunes (13,16%), les toxidermies (10,53%), les ulcères veineux (6,58%), les ulcères artériels (3,95%), les tumeurs malignes (5,27%), les plaies diabétiques (3,95%). Nous avons noté 4 décès (5,26%). Conclusion Cette étude a montré une proportion élevée des sujets âgés de 60 ans et plus en milieu dermatologique à Bamako. Par ailleurs, elle confirme que les dermohypodermites sont les pathologies cutanées les plus fréquentes chez le sujet âgé hospitalisé au Mali. PMID:28292163

Prediction du profil de durete de l'acier AISI 4340 traite thermiquement au laser

NASA Astrophysics Data System (ADS)

Maamri, Ilyes

Les traitements thermiques de surfaces sont des procedes qui visent a conferer au coeur et a la surface des pieces mecaniques des proprietes differentes. Ils permettent d'ameliorer la resistance a l'usure et a la fatigue en durcissant les zones critiques superficielles par des apports thermiques courts et localises. Parmi les procedes qui se distinguent par leur capacite en terme de puissance surfacique, le traitement thermique de surface au laser offre des cycles thermiques rapides, localises et precis tout en limitant les risques de deformations indesirables. Les proprietes mecaniques de la zone durcie obtenue par ce procede dependent des proprietes physicochimiques du materiau a traiter et de plusieurs parametres du procede. Pour etre en mesure d'exploiter adequatement les ressources qu'offre ce procede, il est necessaire de developper des strategies permettant de controler et regler les parametres de maniere a produire avec precision les caracteristiques desirees pour la surface durcie sans recourir au classique long et couteux processus essai-erreur. L'objectif du projet consiste donc a developper des modeles pour predire le profil de durete dans le cas de traitement thermique de pieces en acier AISI 4340. Pour comprendre le comportement du procede et evaluer les effets des differents parametres sur la qualite du traitement, une etude de sensibilite a ete menee en se basant sur une planification experimentale structuree combinee a des techniques d'analyse statistiques eprouvees. Les resultats de cette etude ont permis l'identification des variables les plus pertinentes a exploiter pour la modelisation. Suite a cette analyse et dans le but d'elaborer un premier modele, deux techniques de modelisation ont ete considerees, soient la regression multiple et les reseaux de neurones. Les deux techniques ont conduit a des modeles de qualite acceptable avec une precision d'environ 90%. Pour ameliorer les performances des modeles a base de reseaux de neurones, deux nouvelles approches basees sur la caracterisation geometrique du profil de durete ont ete considerees. Contrairement aux premiers modeles predisant le profil de durete en fonction des parametres du procede, les nouveaux modeles combinent les memes parametres avec les attributs geometriques du profil de durete pour refleter la qualite du traitement. Les modeles obtenus montrent que cette strategie conduit a des resultats tres prometteurs.

Les caractéristiques de la collaboration mère-enfant à 48 mois dans deux tâches de numération

PubMed Central

Caron, Lisbeth; Parent, Sophie; Normandeau, Sylvie; Tremblay, Richard E.; Séguin, Jean R.

2017-01-01

RÉSUMÉ Afin d’étudier les connaissances relatives au développement de la numération à l’âge préscolaire, cette recherche examine les manifestations de ces compétences dans un contexte de collaboration mère-enfant. La collaboration entre les mères et leur enfant de 4 ans (n = 193) est observée et analysée dans le contexte de deux tâches de numération. Les résultats complètent les études antérieures sur les compétences maîtrisées par les enfants d’âge préscolaire en performance individuelle en identifiant les compétences en cours d’acquisition exercées avec le soutien de la mère. Les résultats montrent ainsi que les mères ajustent les exigences de la tâche aux compétences de leur enfant afin d’étayer l’exercice de leurs compétences : elles modèlent les compétences numéraires nouvelles et elles soutiennent l’exercice par l’enfant des compétences maîtrisées ou en voie de l’être. Les résultats indiquent également qu’au-delà de l’encadrement de la participation et du transfert progressif des responsabilités cognitives à l’enfant, l’étayage maternel en contexte de numération favorise aussi le soutien de la motivation de l’enfant et le maintien d’un climat affectif harmonieux. PMID:28566773

Mental Health and Service Issues Faced by Older Immigrants in Canada: A Scoping Review.

PubMed

Guruge, Sepali; Thomson, Mary Susan; Seifi, Sadaf Grace

2015-12-01

RÉSUMÉ Une population vieillissante et la croissance de la population sur la base de l'immigration nécessitent que la recherche, la pratique et la politique doivent se concentrer sur la santé mentale des immigrants âgés, surtout parce que leur santé mentale semble se détériorer au fil du temps. Cette revue se concentre sur: Qu'est-ce que l'on sait sur les déterminants sociaux de la santé mentale chez les immigrants âgés, et quels sont les obstacles à l'accès aux services de santé mentale confrontés par les immigrants âgés? Les résultats révèlent que (1) les déterminants sociaux décisifs de la santé mentale sont la culture, le sexe et les services de santé; (2) que les immigrants plus âgés utilisent les services de santé mentale de moins que leurs homologues nés au Canada à cause des obstacles tels que, par exemple, les croyances et les valeurs culturelles, un manque de services culturellement et linguistiquement appropriées, des difficultés financières, et l'âgisme; et (3) quelles que soient les sous-catégories dans cette population, les immigrants âgés éprouvent des inégalités en matière de la santé mentale. La preuve des recherches disponibles indique que de combler les lacunes des service de santé mentale devrait devenir une priorité pour la politique et la pratique du système de soins de santé au Canada.

Peer Assessment Enhances Student Learning: The Results of a Matched Randomized Crossover Experiment in a College Statistics Class.

PubMed

Sun, Dennis L; Harris, Naftali; Walther, Guenther; Baiocchi, Michael

2015-01-01

Feedback has a powerful influence on learning, but it is also expensive to provide. In large classes it may even be impossible for instructors to provide individualized feedback. Peer assessment is one way to provide personalized feedback that scales to large classes. Besides these obvious logistical benefits, it has been conjectured that students also learn from the practice of peer assessment. However, this has never been conclusively demonstrated. Using an online educational platform that we developed, we conducted an in-class matched-set, randomized crossover experiment with high power to detect small effects. We establish that peer assessment causes a small but significant gain in student achievement. Our study also demonstrates the potential of web-based platforms to facilitate the design of high-quality experiments to identify small effects that were previously not detectable.

Biogeomorphic feedback between plant growth and flooding causes alternative stable states in an experimental floodplain

NASA Astrophysics Data System (ADS)

Wang, Chen; Wang, Qiao; Meire, Dieter; Ma, Wandong; Wu, Chuanqing; Meng, Zhen; Van de Koppel, Johan; Troch, Peter; Verhoeven, Ronny; De Mulder, Tom; Temmerman, Stijn

2016-07-01

It is important to understand the mechanisms of vegetation establishment on bare substrate in a disturbance-driven ecosystem because of many valuable ecosystem services. This study tested for empirical indications of local alternative stable states controlled by biogeomorphic feedbacks using flume experiments with alfalfa: (1) single flood experiments different in flood intensity and plant growth, (2) long-term evolution experiments with repeated flooding and seeding. We observed: (1) a combination of thresholds in plant growth and flooding magnitude for upgrowing seedlings to survive; (2) bimodality in vegetation biomass after floods indicating the existence of two alternative states, either densely vegetated or bare; (3) facilitation of vegetation establishment by the spatial pattern formation of channels and sand bars. In conclusion, empirical indicators were demonstrated for local alternative stable states in a disturbance-driven ecosystem associated with biogeomorphic feedbacks, which could contribute to the protection and restoration of vegetation in such ecosystems.

Le contrôle des infections au cabinet du pédiatre

PubMed Central

2008-01-01

RÉSUMÉ La transmission des infections au cabinet du pédiatre est de plus en plus préoccupante. Le présent document expose les voies de transmission des infections et les principes sous-jacents aux mesures actuelles pour contrôler les infections. Pour prévenir les infections, il faut bien concevoir le cabinet et adopter des politiques administratives et de triage convenables, de même que des pratiques de base pour les soins de tous les patients (p. ex., hygiène des mains, port de gants, de masques, de lunettes de protection et d’une blouse d’hôpital pour des interventions précises; nettoyage, désinfection et stérilisation convenables des surfaces et du matériel, y compris les jouets, et techniques d’asepsie en cas d’interventions effractives) et des précautions additionnelles en cas d’infections précises. Le personnel doit avoir reçu les vaccins pertinents, et les personnes infectées doivent respecter les politiques de restriction au travail.

La planification préalable des soins pour les patients en pédiatrie

PubMed Central

2008-01-01

RÉSUMÉ Les progrès médicaux et technologiques ont permis d’ac-croître les taux de survie et d’améliorer la qualité de vie des nourrissons, des enfants et des adolescents ayant des maladies chroniques mettant la vie en danger. La planifi-cation préalable des soins inclut le processus relié aux discussions sur les traitements essentiels au maintien de la survie et la détermination des objectifs des soins de longue durée. Les dispensateurs de soins pédiatriques ont l’obligation éthique d’assimiler cet aspect des soins médicaux. Le présent document de principes vise à aider les dispensateurs de soins à discuter de la planification préalable des soins des patients pédiatriques dans diverses situations. La planification préalable des soins exige des communications efficaces afin de clarifier les objectifs des soins et de s’entendre sur les traitements pertinents ou non pour réaliser ces objectifs, y compris les mesures de réanimation et les mesures palliatives.

Not Too Old, Not Too Young: Older Women's Perceptions of Physicians.

PubMed

MacRae, Hazel

2015-12-01

RÉSUMÉ Les femmes plus âgées interagissent avec les médecins plus souvent que les hommes âgés et les personnes plus jeunes; pourtant, la connaissance et la compréhension de leurs expériences avec les médecins sont limitées. Le but de cette étude était d'étudier les perceptions des femmes âgées de leurs interactions avec les médecins et d'identifier ce que les femmes veulent de leurs médecins. Les entrevues en profondeur avec 30 femmes âgées montrent que la majorité veulent être impliquée activement dans leurs propres soins de santé. Dans la relation patient-médecin, les femmes donnent généralement la priorité aux qualités personnelles de médecins et leur comportement à l'égard du patient. Pour de nombreuses femmes, l'âge et le sexe du médecin ont aussi leur importance.

Numerical experiment for ultrasonic-measurement-integrated simulation of three-dimensional unsteady blood flow.

PubMed

Funamoto, Kenichi; Hayase, Toshiyuki; Saijo, Yoshifumi; Yambe, Tomoyuki

2008-08-01

Integration of ultrasonic measurement and numerical simulation is a possible way to break through limitations of existing methods for obtaining complete information on hemodynamics. We herein propose Ultrasonic-Measurement-Integrated (UMI) simulation, in which feedback signals based on the optimal estimation of errors in the velocity vector determined by measured and computed Doppler velocities at feedback points are added to the governing equations. With an eye towards practical implementation of UMI simulation with real measurement data, its efficiency for three-dimensional unsteady blood flow analysis and a method for treating low time resolution of ultrasonic measurement were investigated by a numerical experiment dealing with complicated blood flow in an aneurysm. Even when simplified boundary conditions were applied, the UMI simulation reduced the errors of velocity and pressure to 31% and 53% in the feedback domain which covered the aneurysm, respectively. Local maximum wall shear stress was estimated, showing both the proper position and the value with 1% deviance. A properly designed intermittent feedback applied only at the time when measurement data were obtained had the same computational accuracy as feedback applied at every computational time step. Hence, this feedback method is a possible solution to overcome the insufficient time resolution of ultrasonic measurement.

Impact of a novel teaching method based on feedback, activity, individuality and relevance on students' learning.

PubMed

Edafe, Ovie; Brooks, William S; Laskar, Simone N; Benjamin, Miles W; Chan, Philip

2016-03-20

This study examines the perceived impact of a novel clinical teaching method based on FAIR principles (feedback, activity, individuality and relevance) on students' learning on clinical placement. This was a qualitative research study. Participants were third year and final year medical students attached to one UK vascular firm over a four-year period (N=108). Students were asked to write a reflective essay on how FAIRness approach differs from previous clinical placement, and its advantages and disadvantages. Essays were thematically analysed and globally rated (positive, negative or neutral) by two independent researchers. Over 90% of essays reported positive experiences of feedback, activity, individuality and relevance model. The model provided multifaceted feedback; active participation; longitudinal improvement; relevance to stage of learning and future goals; structured teaching; professional development; safe learning environment; consultant involvement in teaching. Students perceived preparation for tutorials to be time intensive for tutors/students; a lack of teaching on medical sciences and direct observation of performance; more than once weekly sessions would be beneficial; some issues with peer and public feedback, relevance to upcoming exam and large group sizes. Students described negative experiences of "standard" clinical teaching. Progressive teaching programmes based on the FAIRness principles, feedback, activity, individuality and relevance, could be used as a model to improve current undergraduate clinical teaching.

The neural representation of typical and atypical experiences of negative images: comparing fear, disgust and morbid fascination

PubMed Central

Lindquist, Kristen A.; Adebayo, Morenikeji; Barrett, Lisa Feldman

2016-01-01

Negative stimuli do not only evoke fear or disgust, but can also evoke a state of ‘morbid fascination’ which is an urge to approach and explore a negative stimulus. In the present neuroimaging study, we applied an innovative method to investigate the neural systems involved in typical and atypical conceptualizations of negative images. Participants received false feedback labeling their mental experience as fear, disgust or morbid fascination. This manipulation was successful; participants judged the false feedback correct for 70% of the trials on average. The neuroimaging results demonstrated differential activity within regions in the ‘neural reference space for discrete emotion’ depending on the type of feedback. We found robust differences in the ventrolateral prefrontal cortex, the dorsomedial prefrontal cortex and the lateral orbitofrontal cortex comparing morbid fascination to control feedback. More subtle differences in the dorsomedial prefrontal cortex and the lateral orbitofrontal cortex were also found between morbid fascination feedback and the other emotion feedback conditions. This study is the first to forward evidence about the neural representation of the experimentally unexplored state of morbid fascination. In line with a constructionist framework, our findings suggest that neural resources associated with the process of conceptualization contribute to the neural representation of this state. PMID:26180088

The Schultz MIDI Benchmarking Toolbox for MIDI interfaces, percussion pads, and sound cards.

PubMed

Schultz, Benjamin G

2018-04-17

The Musical Instrument Digital Interface (MIDI) was readily adopted for auditory sensorimotor synchronization experiments. These experiments typically use MIDI percussion pads to collect responses, a MIDI-USB converter (or MIDI-PCI interface) to record responses on a PC and manipulate feedback, and an external MIDI sound module to generate auditory feedback. Previous studies have suggested that auditory feedback latencies can be introduced by these devices. The Schultz MIDI Benchmarking Toolbox (SMIDIBT) is an open-source, Arduino-based package designed to measure the point-to-point latencies incurred by several devices used in the generation of response-triggered auditory feedback. Experiment 1 showed that MIDI messages are sent and received within 1 ms (on average) in the absence of any external MIDI device. Latencies decreased when the baud rate increased above the MIDI protocol default (31,250 bps). Experiment 2 benchmarked the latencies introduced by different MIDI-USB and MIDI-PCI interfaces. MIDI-PCI was superior to MIDI-USB, primarily because MIDI-USB is subject to USB polling. Experiment 3 tested three MIDI percussion pads. Both the audio and MIDI message latencies were significantly greater than 1 ms for all devices, and there were significant differences between percussion pads and instrument patches. Experiment 4 benchmarked four MIDI sound modules. Audio latencies were significantly greater than 1 ms, and there were significant differences between sound modules and instrument patches. These experiments suggest that millisecond accuracy might not be achievable with MIDI devices. The SMIDIBT can be used to benchmark a range of MIDI devices, thus allowing researchers to make informed decisions when choosing testing materials and to arrive at an acceptable latency at their discretion.

A mathematical analysis of rebound in a target-mediated drug disposition model: II. With feedback.

PubMed

Aston, Philip J; Derks, Gianne; Agoram, Balaji M; van der Graaf, Piet H

2017-07-01

We consider the possibility of free receptor (antigen/cytokine) levels rebounding to higher than the baseline level after the application of an antibody drug using a target-mediated drug disposition model. It is assumed that the receptor synthesis rate experiences homeostatic feedback from the receptor levels. It is shown for a very fast feedback response, that the occurrence of rebound is determined by the ratio of the elimination rates, in a very similar way as for no feedback. However, for a slow feedback response, there will always be rebound. This result is illustrated with an example involving the drug efalizumab for patients with psoriasis. It is shown that slow feedback can be a plausible explanation for the observed rebound in this example.

Are Japanese groups more competitive than Japanese individuals? A cross-cultural validation of the interindividual-intergroup discontinuity effect.

PubMed

Takemura, Kosuke; Yuki, Masaki

2007-02-01

The interindividual-intergroup discontinuity effect is the tendency for relationships between groups to be more competitive than the relationships between individuals. It has been observed robustly in studies conducted in the United States, which is a society characterized as "individualistic." In this study, it was explored whether the effect was replicable in a "collectivistic" society such as Japan. From the traditional view in cross-cultural psychology, which emphasizes the collectivistic nature of East Asian peoples, it was expected that the discontinuity effect would be greater in Japan than in the United States. On the other hand, based on recent empirical findings suggesting that North Americans are no less group-oriented than East Asians, it was expected that the discontinuity effect would be no greater in Japan than in the United States. One hundred and sixty Japanese university students played a 10-trial repeated prisoner's dilemma game: 26 sessions of interindividual and 18 sessions of intergroup. Following exactly the procedure of prior experiments in the US, individuals and groups were allowed face-to-face communication with their opponents before making their decisions, and participants in the intergroup condition were further allowed to converse freely with their in-group members. Results replicated previous findings in the United States; groups made more competitive choices than did individuals. In addition, neither the magnitude of the discontinuity effect, nor the frequency of competitive choices made by the groups, were larger in Japan than they were in the majority of prior studies conducted in the United States. These findings suggest cross-cultural robustness of the interindividual-intergroup discontinuity effect. Also, interestingly, they contradict the simple distinction between individualism and collectivism. Implications for studies of culture and group processes are discussed. This research was supported by grants from the Center for the Study of Cultural and Ecological Foundations of the Mind, a 21(st) Century Center of Excellence Program at Hokkaido University. The authors would like to thank Dr. Laura Hernández-Guzmán, three anonymous reviewers, and Robin Cooper, Mark H. B. Radford, and Paul A. Wehr for their helpful comments on earlier versions of this article. They would also like to thank Dr. Chester A. Insko for his kind and valuable advice during the planning of this experiment as well as the interpretation of its results, Kaori Akaishi for her help with data collection, and, finally, colleagues at Hokkaido University who helped to recruit potential participants from their classes. L'effet de discontinuité entre les individus et entre les groupes est la tendance des relations entre les groupes à être plus compétitives que les relations entre les individus. Cet effet fut fermement démontré dans des études menées aux États-Unis, une société caractérisée d' «individualiste». Dans la présente étude, nous avons exploré dans quelle mesure l'effet était applicable à une société «collectiviste» comme le Japon. À partir du point de vue traditionnel de la psychologie interculturelle, laquelle met l'emphase sur la nature collectiviste des peuples de l'Asie de l'Est, il était attendu que l'effet de discontinuité allait être plus grand au Japon qu'aux États-Unis. D'un autre côté, se basant sur les données empiriques récentes qui suggèrent que les Nord-américains ne sont pas moins orientés vers le groupe que les Asiatiques de l'Est, il était attendu que l'effet de discontinuité ne serait pas plus important au Japon qu'aux États-Unis. Cent soixante étudiants universitaires japonais ont pris part à un jeu de dilemme de prisonnier de 10 essais répétés: 26 sessions entre individus et 18 sessions entre groupes. Suivant exactement la procédure des expériences menées précédemment aux États-Unis, les individus et les groupes avaient la permission de communiquer face-à-face avec leur opposant avant de prendre leur décision. De plus, les participants de la condition entre groupes avaient également la possibilité de converser librement avec les membres de leur propre groupe. Les résultats se sont révélés semblables à ceux des études antérieures réalisées aux États-Unis; les groupes ont fait des choix plus compétitifs que les individus. En outre, ni la magnitude de l'effet de discontinuité, ni la fréquence des choix compétitifs faits par les groupes n'étaient plus grands chez les Japonais comparativement à la majorité des études antérieures menées aux États-Unis. Ces résultats soutiennent la robustesse interculturelle de l'effet de discontinuité entre les individus et entre les groupes. Aussi, fait intéressant, ils contredisent la simple distinction entre l'individualisme et le collectivisme. Les implications pour des études sur les cultures et les processus de groupe sont discutées. El efecto de discontinuidad entre individuos y entre grupos es la tendencia a que las relaciones entre grupos sean más competitivas que las relaciones entre individuos. Se ha observado con insistencia en estudios conducidos en Estados Unidos, una sociedad caracterizada como "individualista". En el presente estudio, se exploró si el efecto se repetía en una sociedad "colectivista" como la japonesa. Desde la perspectiva tradicional de la psicología trans cultural, que subraya la naturaleza colectivista de los pueblos asiáticos, se esperaba que el efecto de discontinuidad fuese mayor en Japón que en Estados Unidos. Por otra parte, con base en los hallazgos empíricos recientes que sugieren que los estadounidenses no están menos orientados al grupo que los de este asiático, se esperaba que el efecto de discontinuidad no fuera mayor en Japón que en los Estados Unidos. Ciento sesenta estudiantes universitarios japoneses participaron en un juego del dilema de un prisionero de diez ensayos repetidos: veintiséis sesiones entre individuos y diez y ocho entre grupos. Siguiendo exactamente el procedimiento de los experimentos previos en los Estados Unidos, se permitió tanto a los individuos como a los grupos una comunicación cara a cara con sus oponentes antes de tomar sus decisiones, y se permitió a los participantes en la condición entre grupos que conversaran libremente con los miembros de su propio grupo. Los resultados repitieron los hallazgos previos en los Estados Unidos; los grupos hicieron elecciones más competitivas que los individuos. Además, ni la magnitud del efecto de discontinuidad ni la frecuencia de las elecciones competitivas de los grupos, fueron mayores en Japón que en la mayoría de los estudios previos en Estados Unidos. Estos hallazgos sugieren la robustez trans cultural del efecto de discontinuidad entre individuos y entre grupos. También, de manera interesante, contradicen la simple distinción entre individualismo y colectivismo. Se discutieron las implicaciones para los estudios sobre cultura y procesos grupales.

Les calculs urinaires de l'enfant au Burkina Faso: à propos de 67 cas

PubMed Central

Ouédraogo, Isso; Napon, Aïcha Madina; Bandré, Emile; Ouédraogo, Francis Somkieta; Tapsoba, Wendlamita Toussaint; Wandaogo, Albert

2015-01-01

L'objectif de cette étude est de déterminer la fréquence, de décrire les circonstances de découverte, les signes cliniques et paracliniques, la composition chimique des calculs prélevés et les difficultés rencontrées dans le traitement des lithiases urinaires. Notre étude a été rétrospective sur une période de six ans (janvier 2005 à décembre 2010) et a eu pour cadre le CHUP-CDG et a concerné 67 patients âgés de moins de 15 ans opérés pour lithiases urinaires. Les calculs de la dernière année au nombre de douze ont fait l'objet d'une analyse spectrophotométrique. La lithiase urinaire figure parmi les dix premières pathologies du service de chirurgie et représente 1,32% des hospitalisations. L’âge moyen de nos patients est de deux ans et varie de 6 mois à 14 ans. La symptomatologie de la lithiase urinaire est polymorphe. Le diagnostic des lithiases urinaires a été essentiellement radiologique (ASP) dans 87, 50 des cas. Les localisations les plus fréquentes sont: vésicales (49,25%) et pyéliques (46,26%). L'ECBU a révélé une infection urinaire chez 9 patients. Les germes le plus fréquemment rencontrés sont: Klebsiella pneumoniae pneumoniae (22,22%) et staphyloccocus aureus (22,22%). Les difficultés du traitement sont dues à la modicité de nos moyens diagnostiques et à la nature chimique des calculs et le traitement a été dans tous les cas chirurgical. La composition chimique est dominée par les sels calciques notamment les oxalates, les phosphates et les carbonates. PMID:26175840

Douleurs induites par les soins: la réalité au Centre Hospitalier Universitaire de Befelatanana Antananarivo, Madagascar

PubMed Central

Mahavivola, Ernestho-Ghoud Indretsy; Olivah, Razanaparany Miarisoa Mireille; Mihary, Dodo; Hendriniaina, Rakotoharivelo; Lalao, Randriamboavonjy Rado; Henintsoa, Rakotonirainy Oliva; Fahafahantsoa, Rapelanoro Rabenja

2014-01-01

La douleur induite par les soins correspond à la douleur survenant lors des actes à visé diagnostique et/ou thérapeutique. A notre connaissance, nous n'avons pas encore des données disponibles pour les douleurs induites par les soins à l'Hôpital de Befelatanana. Nos objectifs étaient de décrire le profil épidémiologique de la douleur induite par les soins, d'identifier les principaux facteurs influençant sur l'intensité de la douleur et leurs retentissements chez les patients. Il s'agissait d'une étude rétrospective, transversale type un jour donné menée dans les douze services de Médecines au Centre Hospitalier Universitaire de Befelatanana en Novembre 2013. Cent deux patients ont été retenus dans l’étude et trois cent vingt trois actes douloureux étaient enregistrés. La fréquence de la douleur induite par les soins était de 69,86%. Le genre féminin prédominait dans 52% des cas (n = 53) avec un sex-ratio à 0,92. L’âge moyen était de 46 ans. Les ponctions vasculaires étaient l'acte prédominant dans 49,54% (n = 109) des cas. Les infirmiers réalisaient les soins dans 47,05% (n = 48) des cas. L'information verbale était la mesure préventive utilisée dans 57,84% des cas (n = 59). Le transport par marche à pied et au dos représentait 16,67% des cas (n = 17). Les patients naïfs des gestes étaient plus anxieux. Ces patients gardaient de mauvais souvenir dans 64,71% des cas (n = 66). La fréquence de douleur induite par les soins était trop élevée. Un effort important est nécessaire pour réduire la douleur induite par les soins PMID:25932071

Shadowing emergency medicine residents by medical education specialists to provide feedback on non-medical knowledge-based ACGME sub-competencies.

PubMed

Waterbrook, Anna L; Spear Ellinwood, Karen C; Pritchard, T Gail; Bertels, Karen; Johnson, Ariel C; Min, Alice; Stoneking, Lisa R

2018-01-01

Non-medical knowledge-based sub-competencies (multitasking, professionalism, accountability, patient-centered communication, and team management) are challenging for a supervising emergency medicine (EM) physician to evaluate in real-time on shift while also managing a busy emergency department (ED). This study examines residents' perceptions of having a medical education specialist shadow and evaluate their nonmedical knowledge skills. Medical education specialists shadowed postgraduate year 1 and postgraduate year 2 EM residents during an ED shift once per academic year. In an attempt to increase meaningful feedback to the residents, these specialists evaluated resident performance in selected non-medical knowledge-based Accreditation Council of Graduate Medical Education (ACGME) sub-competencies and provided residents with direct, real-time feedback, followed by a written evaluation sent via email. Evaluations provided specific references to examples of behaviors observed during the shift and connected these back to ACGME competencies and milestones. Twelve residents participated in this shadow experience (six post graduate year 1 and six postgraduate year 2). Two residents emailed the medical education specialists ahead of the scheduled shadow shift requesting specific feedback. When queried, five residents voluntarily requested their feedback to be included in their formal biannual review. Residents received milestone scores and narrative feedback on the non-medical knowledge-based ACGME sub-competencies and indicated the shadow experience and subsequent feedback were valuable. Medical education specialists who observe residents over the course of an entire shift and evaluate non-medical knowledge-based skills are perceived by EM residents to provide meaningful feedback and add valuable information for the biannual review process.

Assessing Technology in the Absence of Proof: Trust Based on the Interplay of Others' Opinions and the Interaction Process.

PubMed

de Vries, Peter W; van den Berg, Stéphanie M; Midden, Cees

2015-12-01

The present research addresses the question of how trust in systems is formed when unequivocal information about system accuracy and reliability is absent, and focuses on the interaction of indirect information (others' evaluations) and direct (experiential) information stemming from the interaction process. Trust in decision-supporting technology, such as route planners, is important for satisfactory user interactions. Little is known, however, about trust formation in the absence of outcome feedback, that is, when users have not yet had opportunity to verify actual outcomes. Three experiments manipulated others' evaluations ("endorsement cues") and various forms of experience-based information ("process feedback") in interactions with a route planner and measured resulting trust using rating scales and credits staked on the outcome. Subsequently, an overall analysis was conducted. Study 1 showed that effectiveness of endorsement cues on trust is moderated by mere process feedback. In Study 2, consistent (i.e., nonrandom) process feedback overruled the effect of endorsement cues on trust, whereas inconsistent process feedback did not. Study 3 showed that although the effects of consistent and inconsistent process feedback largely remained regardless of face validity, high face validity in process feedback caused higher trust than those with low face validity. An overall analysis confirmed these findings. Experiential information impacts trust even if outcome feedback is not available, and, moreover, overrules indirect trust cues-depending on the nature of the former. Designing systems so that they allow novice users to make inferences about their inner workings may foster initial trust. © 2015, Human Factors and Ergonomics Society.

Motivation in vigilance - Effects of self-evaluation and experimenter-controlled feedback.

NASA Technical Reports Server (NTRS)

Warm, J. S.; Kanfer, F. H.; Kuwada, S.; Clark, J. L.

1972-01-01

Vigilance experiments have been performed to study the relative efficiency of feedback operations in enhancing vigilance performance. Two feedback operations were compared - i.e., experimenter-controlled feedback in the form of knowledge of results (KR) regarding response times to signal detections, and subject-controlled feedback in the form of self-evaluation (SE) of response times to signal detections. The subjects responded to the aperiodic offset of a visual signal during a 1-hr vigil. Both feedback operations were found to enhance performance efficiency: subjects in the KR and SE conditions had faster response times than controls receiving no evaluative feedback. Moreover, the data of the KR and SE groups did not differ significantly from each other. The results are discussed in terms of the hypothesis that self-evaluation is a critical factor underlying the incentive value of KR in vigilance tasks.

Robust permanence for ecological equations with internal and external feedbacks.

PubMed

Patel, Swati; Schreiber, Sebastian J

2018-07-01

Species experience both internal feedbacks with endogenous factors such as trait evolution and external feedbacks with exogenous factors such as weather. These feedbacks can play an important role in determining whether populations persist or communities of species coexist. To provide a general mathematical framework for studying these effects, we develop a theorem for coexistence for ecological models accounting for internal and external feedbacks. Specifically, we use average Lyapunov functions and Morse decompositions to develop sufficient and necessary conditions for robust permanence, a form of coexistence robust to large perturbations of the population densities and small structural perturbations of the models. We illustrate how our results can be applied to verify permanence in non-autonomous models, structured population models, including those with frequency-dependent feedbacks, and models of eco-evolutionary dynamics. In these applications, we discuss how our results relate to previous results for models with particular types of feedbacks.

Time delay signature elimination of chaos in a semiconductor laser by dispersive feedback from a chirped FBG.

PubMed

Wang, Daming; Wang, Longsheng; Zhao, Tong; Gao, Hua; Wang, Yuncai; Chen, Xianfeng; Wang, Anbang

2017-05-15

Time delay signature (TDS) of a semiconductor laser subject to dispersive optical feedback from a chirped fibre Bragg grating (CFBG) is investigated experimentally and numerically. Different from mirror, CFBG provides additional frequency-dependent delay caused by dispersion, and thus induces external-cavity modes with irregular mode separation rather than a fixed separation induced by mirror feedback. Compared with mirror feedback, the CFBG feedback can greatly depress and even eliminate the TDS, although it leads to a similar quasi-period route to chaos with increases of feedback. In experiments, by using a CFBG with dispersion of 2000ps/nm, the TDS is decreased by 90% to about 0.04 compared with mirror feedback. Furthermore, both numerical and experimental results show that the TDS evolution is quite different: the TDS decreases more quickly down to a lower plateau (even background noise level of autocorrelation function) and never rises again. This evolution tendency is also different from that of FBG feedback, of which the TDS first decreases to a minimal value and then increases again as feedback strength increases. In addition, the CFBG feedback has no filtering effects and does not require amplification for feedback light.

Evaluating plant-soil feedback together with competition in a serpentine grassland.

PubMed

Casper, Brenda B; Castelli, Jeffrey P

2007-05-01

Plants can alter biotic and abiotic soil characteristics in ways that feedback to change the performance of that same plant species relative to co-occurring plants. Most evidence for this plant-soil feedback comes from greenhouse studies of potted plants, and consequently, little is known about the importance of feedback in relation to other biological processes known to structure plant communities, such as plant-plant competition. In a field experiment with three C4 grasses, negative feedback was expressed through reduced survival and shoot biomass when seedlings were planted within existing clumps of conspecifics compared with clumps of heterospecifics. However, the combined effects of feedback and competition were species-specific. Only Andropogon gerardii exhibited feedback when competition with the clumps was allowed. For Sorghastrum nutans, strong interspecific competition eliminated the feedback expressed in the absence of competition, and Schizachyrium scoparium showed no feedback at all. That arbuscular mycorrhizal (AM) fungi may play a role in the feedback was indicated by higher AM root colonization with conspecific plant neighbours. We suggest that feedback and competition should not be viewed as entirely separate processes and that their importance in structuring plant communities cannot be judged in isolation from each other.

N° 341-Diagnostic et prise en charge de la torsion annexielle chez les filles, les adolescentes et les femmes adultes.

PubMed

Kives, Sari; Gascon, Suzy; Dubuc, Élise; Van Eyk, Nancy

2017-02-01

Passer en revue les connaissances scientifiques actuelles et formuler des recommandations relatives au diagnostic et à la prise en charge de la torsion annexielle chez les filles, les adolescentes et les femmes adultes. L'étude porte sur les facteurs de risque, la précision diagnostique, les options de prise en charge et les issues de la torsion annexielle. RéSULTATS: Nous avons examiné les études publiées en faisant des recherches dans MEDLINE, Embase, CINAHL et la Bibliothèque Cochrane à l'aide d'une terminologie contrôlée et de mots-clés appropriés (« adnexal torsion », « ovarian torsion »). Nous avons limité les résultats aux revues systématiques, aux essais contrôlés aléatoires, aux essais cliniques contrôlés et aux études d'observation. Nous avons refait les recherches de façon régulière et intégré de nouvelles données à la directive jusqu'en décembre 2014. Nous avons également étudié la littérature grise (non publiée) trouvée sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes connexes, dans des collections de directives cliniques et dans des registres d'essais cliniques, et obtenue auprès d'associations nationales et internationales de médecins spécialistes. Les résultats ont été examinés et évalués par le comité CANPAGO de la Société des obstétriciens et gynécologues du Canada (SOGC), sous la direction des auteures principales. Les recommandations ont été classées selon les critères établis par le Groupe d'étude canadien sur les soins de santé préventifs. AVANTAGES, DéSAVANTAGES ET COûTS: L'application de la directive devrait aider les praticiens à adopter une approche de diagnostic et de prise en charge optimale en matière de torsion annexielle, à réduire au minimum les effets néfastes et à améliorer l'issue qui attend les patientes. La présente directive a été évaluée et approuvée par le Comité de pratique - gynécologie de la SOGC, et approuvée par le Conseil de la SOGC. Parrainé par la Société des obstétriciens et gynécologues du Canada. DéCLARATIONS SOMMAIRES: RECOMMANDATIONS. Copyright © 2017. Published by Elsevier Inc.

An evaluation of end-point trajectory planning during skilled kicking.

PubMed

Ford, Paul; Hodges, Nicola J; Mark Williams, A

2009-01-01

There is evidence that actions are planned by anticipation of their external effects, with the strength of this effect being dependent on the amount of prior practice. In Experiment 1, skilled soccer players performed a kicking task under four conditions: planning in terms of an external action effect (i.e., ball trajectory) or in terms of body movements, either with or without visual error feedback. When feedback was withheld, a ball focus resulted in more accurate outcomes than a body focus. When visual feedback was allowed, there was no difference between these two conditions. In Experiment 2, both skilled and novice soccer players were tested with the addition of a control condition and in the absence of visual feedback. For both groups there was evidence that a ball focus was more beneficial for performance than a body focus, particularly in terms of movement kinematics where correlations across the joints were generally higher for body rather than ball planning. Most skilled participants reported that ball planning felt more normal than body planning. These experiments provide some evidence that actions are planned in terms of their external action effects, supporting the common-coding hypothesis of action planning.

Intrinsic mechanical properties and strengthening methods in inorganic crystalline materials

NASA Astrophysics Data System (ADS)

Mecking, H.; Hartig, Ch.; Seeger, J.

1991-06-01

The paper deals with strength and fracture in metals, ceramics and intermetallic compounds. The emphasis is on the interrelation between microstructure and macroscopic behavior and how the concepts for alloy design are mirroring this interrelationship. The three materials classes are distinguished by the physical nature of the atomic bonding forces. In metals metallic bonding predominates which causes high ductility but poor strength. Accordingly material development concentrates on production of microstructures which optimize the yield strength without unacceptable loss in ductility. In ceramics covalent bonding prevails which results in high hardness and high elastic stiffness but at the same time extreme brittleness. Contrary to the metal-ease material development aims at a kind of pseudo ductility in order to rise the fracture toughness to sufficiently high levels. In intermetallic phases the atomic bonds are a mixture of metallic and covalent bonding where depending on the alloying system the balance between the two contributions may be quite different. Accordingly the properties of intermetallics are in the range between metals and ceramics. By a variety of microstructural measures their properties can be changed in direction. either towards metallic or ceramic behavior. General rules for alloy design are not available, rather every system demands very specific experience since properties depend to a considerable part on intrinsic properties of lattice defects such as dislocations, antiphase boundaries, stacking faults and grain boundaries. Cet article traite de la résistance et de la fracture des métaux, des céramiques et des composés intermétalliques. L'accent est mis sur les correspondances entre la microstructure et le comportement macroscopique ainsi que sur la façon dont de tels concepts se reflètent dans la création de nouveaux alliages. C'est la nature des forces de liaisons qui distingue chaque type de matériaux. Dans les métaux, les liaisons métalliques dominent, ce qui entraîne une grande ductilité mais une médiocre résistance. En conséquence, dans le développement de nouveaux matériaux on cherche préférentiellement à produire des microstructures qui optimisent la résistance élastique sans perte inacceptable de ductilité. Dans les céramiques, les liaisons covalentes prédominent; ceci entraîne une dureté élevée, une grande rigidité, mais en même temps une extrême fragilité. Au contraire des métaux, le développement de ces matériaux vise à obtenir une pseudoductilité afin d'amener la tenacité à des niveaux suffisamment élevés. Dans les phases intermétalliques les liaisons atomiques correspondent à un mélange de liaisons métalliques et covalentes. La contribution de chacune d'entre elles varie en fonction du système allié. En conséquence, les propriétés des intermétalliques se situent entre celles des métaux et des céramiques. Par divers changements microstructuraux des propriétés peuvent être déplacées pour se rapprocher d'un comportement de type métallique ou de type céramique. Donner des règles générales pour la création de nouveaux alliages n'est pas possible car chaque système demande à être testé, les propriétés dépendent en effet, pour une part considérable, des propriétés intrinsèques des défauts de réseau comme les dislocations, les parois d'antiphase ou les joints de grains.

ESCOMPTE experiment: intercomparison of four aircraft dynamical, thermodynamical, radiation and chemical measurements

NASA Astrophysics Data System (ADS)

Saïd, F.; Corsmeier, U.; Kalthoff, N.; Kottmeier, C.; Lothon, M.; Wieser, A.; Hofherr, T.; Perros, P.

2005-03-01

Among seven airplanes involved in the Experience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emission (ESCOMPTE) experiment in 2001, four measured classical meteorological parameters, radiation fluxes, trace gases and turbulence (for three among four): the Dornier 128 from the Institut für Meteorologie und Klimaforschung, the Fokker 27 ARAT from the Institut National des Sciences de l'Univers, the Merlin 4 and Piper Aztec 23 from Météo France. This paper presents the results of intercomparison flights between three pairs of aircraft. The results are very similar for mean parameters except for the horizontal wind measurements provided by the Merlin that showed a problem that is probably linked to the measurement of the aircraft velocity. Further investigation is required to know whether corrections are possible or not for these wind measurements. Turbulence is studied along two legs over a flat and homogeneous area: in spite of the heterogeneity of the measured functions (one leg is close to the top of the boundary layer), the comparison is rather good. The relative accuracy of the data provided to the data base is given. It easily allows to use the huge amount of aircraft data collected during the experiment with very few restrictions. We underline some points where efforts should be borne for future experiments: wind coupling between Inertial Navigation System data and Global Positioning System (GPS) data, CO and NO x measurements.

Effets potentiels d’un modèle rationnel de prescription sur les dépenses nationales en santé

PubMed Central

Littman, Jordan; Halil, Roland

2016-01-01

Résumé Objectif Estimer les économies que pourrait engendrer la mise en œuvre d’un modèle rationnel de prescription pour des classes de médicaments équivalents sur les plans de l’efficacité, de la toxicité et de la commodité. Conception L’Institut canadien d’information sur la santé a fourni des renseignements sur les 10 principales classes de médicaments en fonction des dépenses annuelles qui leur sont attribuables. Ces classes ont été examinées en vue de leur inclusion potentielle dans l’étude selon qu’il était possible de comparer les médicaments à l’intérieur d’une même classe. Lorsqu’à la suite d’une recherche documentaire, une équivalence a été établie en fonction de l’efficacité, de la toxicité et de la commodité des médicaments, les données annuelles sur les prescriptions ont été recueillies à partir de la base de données du Système national d’information sur l’utilisation des médicaments prescrits. Les économies potentielles de coûts ont ensuite été calculées en comparant les parts de marché actuelles avec les parts potentielles futures de ce marché. Contexte Le Canada. Principaux paramètres à l’étude Les différences estimées dans les dépenses que produirait un modèle rationnel de prescription. Résultats Une équivalence a été établie sur les plans de l’efficacité, de la toxicité et de la commodité dans les classes de statines, d’inhibiteurs de la pompe à protons, d’inhibiteurs de l’enzyme de conversion de l’angiotensine et d’inhibiteurs sélectifs du recaptage de l’angiotensine. Les dépenses annuelles totales dans ces classes se situent à 856 millions $ dans les programmes publics de médicaments et à 1,97 milliard $ environ à l’échelle nationale. Grâce à des prescriptions rationnelles, on estime que les économies annuelles pourraient atteindre 222 millions $ pour les programmes publics et 521 millions $ à l’échelle nationale. Conclusion La majorité des économies potentielles seraient attribuables à l’abandon des médicaments les plus récents protégés par un brevet dans chaque classe. En évitant de prescrire les plus récents médicaments intraclasses, en particulier en l’absence de recherche établissant leur supériorité dans les résultats cliniques pertinents, on pourrait réaliser des économies considérables dans les dépenses en santé et inciter l’industrie pharmaceutique à innover plutôt qu’à imiter.

Diagnostiquer l’hypertension artérielle

PubMed Central

Gelfer, Mark; Dawes, Martin; Kaczorowski, Janusz; Padwal, Raj; Cloutier, Lyne

2015-01-01

Résumé Objectif Mettre en lumière les recommandations 2015 du Programme éducatif canadien sur l’hypertension (PECH) sur le diagnostic et l’évaluation de l’hypertension artérielle (HTA). Qualité des données Une recherche systématique remontant à août 2014 a été effectuée par un bibliothécaire de la Collaboration Cochrane dans les banques de données MEDLINE et PubMed. Les résultats de la recherche ont fait l’objet d’une évaluation critique par le sous-comité du PECH sur la mesure de la pression artérielle (PA) et le diagnostic d’HTA, et les recommandations fondées sur les données probantes ont été soumises au Comité central d’examen du PECH aux fins d’examen indépendant et de classement. Finalement, les résultats et recommandations ont été présentés au Groupe de travail sur les recommandations aux fins de discussion, de débat, d’approbation et de vote. Les principales recommandations reposent sur des données probantes de niveau II. Message principal Selon les données probantes les plus récentes, le PECH a formulé 4 nouvelles recommandations classées dans 2 vastes catégories pour améliorer la mesure de la PA et la façon dont l’HTA est diagnostiquée en 2015. Il est fortement recommandé de mesurer la PA à l’aide d’appareils électroniques en clinique plutôt que par auscultation. Chez les patients dont les mesures en clinique sont élevées, le PECH recommande de se tourner précocement vers les mesures ambulatoires, préférablement le monitorage ambulatoire de la PA, afin d’identifier rapidement les patients atteints du syndrome du sarrau blanc. Conclusion Il est crucial d’améliorer la justesse diagnostique afin d’optimiser la prise en charge de l’HTA au Canada. Les mises à jour annuelles du PECH veillent à ce que les praticiens disposent de renseignements fondés sur les données probantes à jour pour éclairer leur pratique.

Impaired Feedforward Control and Enhanced Feedback Control of Speech in Patients with Cerebellar Degeneration.

PubMed

Parrell, Benjamin; Agnew, Zarinah; Nagarajan, Srikantan; Houde, John; Ivry, Richard B

2017-09-20

The cerebellum has been hypothesized to form a crucial part of the speech motor control network. Evidence for this comes from patients with cerebellar damage, who exhibit a variety of speech deficits, as well as imaging studies showing cerebellar activation during speech production in healthy individuals. To date, the precise role of the cerebellum in speech motor control remains unclear, as it has been implicated in both anticipatory (feedforward) and reactive (feedback) control. Here, we assess both anticipatory and reactive aspects of speech motor control, comparing the performance of patients with cerebellar degeneration and matched controls. Experiment 1 tested feedforward control by examining speech adaptation across trials in response to a consistent perturbation of auditory feedback. Experiment 2 tested feedback control, examining online corrections in response to inconsistent perturbations of auditory feedback. Both male and female patients and controls were tested. The patients were impaired in adapting their feedforward control system relative to controls, exhibiting an attenuated anticipatory response to the perturbation. In contrast, the patients produced even larger compensatory responses than controls, suggesting an increased reliance on sensory feedback to guide speech articulation in this population. Together, these results suggest that the cerebellum is crucial for maintaining accurate feedforward control of speech, but relatively uninvolved in feedback control. SIGNIFICANCE STATEMENT Speech motor control is a complex activity that is thought to rely on both predictive, feedforward control as well as reactive, feedback control. While the cerebellum has been shown to be part of the speech motor control network, its functional contribution to feedback and feedforward control remains controversial. Here, we use real-time auditory perturbations of speech to show that patients with cerebellar degeneration are impaired in adapting feedforward control of speech but retain the ability to make online feedback corrections; indeed, the patients show an increased sensitivity to feedback. These results indicate that the cerebellum forms a crucial part of the feedforward control system for speech but is not essential for online, feedback control. Copyright © 2017 the authors 0270-6474/17/379249-10$15.00/0.

Uncertain soil moisture feedbacks in model projections of Sahel precipitation

NASA Astrophysics Data System (ADS)

Berg, Alexis; Lintner, Benjamin R.; Findell, Kirsten; Giannini, Alessandra

2017-06-01

Given the uncertainties in climate model projections of Sahel precipitation, at the northern edge of the West African Monsoon, understanding the factors governing projected precipitation changes in this semiarid region is crucial. This study investigates how long-term soil moisture changes projected under climate change may feedback on projected changes of Sahel rainfall, using simulations with and without soil moisture change from five climate models participating in the Global Land Atmosphere Coupling Experiment-Coupled Model Intercomparison Project phase 5 experiment. In four out of five models analyzed, soil moisture feedbacks significantly influence the projected West African precipitation response to warming; however, the sign of these feedbacks differs across the models. These results demonstrate that reducing uncertainties across model projections of the West African Monsoon requires, among other factors, improved mechanistic understanding and constraint of simulated land-atmosphere feedbacks, even at the large spatial scales considered here.