Science.gov

Sample records for task based exposure

  1. Task-based noise exposures for farmers involved in grain production.

    PubMed

    Humann, M J; Sanderson, W T; Donham, K J; Kelly, K M

    2013-04-01

    Few studies have been done examining noise exposures associated with agricultural tasks. This study was conducted to address that research gap by calculating the noise exposures for tasks and equipment associated with grain production and assessing the variability in those exposures. An additional aim of this study was to identify tasks and equipment that could be targeted for intervention strategies as a means toward reducing the total noise exposures of farmers and farm workers. Through the use of personal noise dosimetry and direct observation, over 30,000 one-minute noise exposure measurements and corresponding task and equipment data were collected on 18 farms and compiled into a task-based noise exposure database. Mean noise exposures were calculated for 23 tasks and 18 pieces of equipment. The noise exposures for the tasks and equipment ranged from 78.6 to 99.9 dBA and from 80.8 to 96.2 dBA, respectively, with most of the noise exposures having a large standard deviation and maximum noise exposure level. Most of the variability in the task and equipment noise exposures was attributable to within-farm variations (e.g., work practices, distance from noise sources). Comparisons of the mean noise exposures for the agricultural tasks and equipment revealed that most were not statistically different. Grain production tasks and equipment with high mean noise exposures were identified. However the substantial variability in the noise exposures and the occurrence of intense noise measurements for nearly every task and piece of equipment indicate that targeting a few specific tasks or equipment for intervention strategies would reduce lifetime noise exposure but would not completely eliminate exposure to hazardous noise levels. PMID:23923730

  2. TASK-BASED EXPOSURE MATRIX TOWARD EVALUATING AND IDENTIFYING OCCUPATIONAL EXPOSURE TO ENGINEERED CARBONACEOUS NANOMATERIALS

    EPA Science Inventory

    It is expected that the findings from this study will contribute to human exposure estimation during the product lifecycle analysis of carbon nanotubes and nanofibers. In addition, the task exposure matrix will provide important background information for the design of future ...

  3. Silica exposure during construction activities: statistical modeling of task-based measurements from the literature.

    PubMed

    Sauvé, Jean-François; Beaudry, Charles; Bégin, Denis; Dion, Chantal; Gérin, Michel; Lavoué, Jérôme

    2013-05-01

    Many construction activities can put workers at risk of breathing silica containing dusts, and there is an important body of literature documenting exposure levels using a task-based strategy. In this study, statistical modeling was used to analyze a data set containing 1466 task-based, personal respirable crystalline silica (RCS) measurements gathered from 46 sources to estimate exposure levels during construction tasks and the effects of determinants of exposure. Monte-Carlo simulation was used to recreate individual exposures from summary parameters, and the statistical modeling involved multimodel inference with Tobit models containing combinations of the following exposure variables: sampling year, sampling duration, construction sector, project type, workspace, ventilation, and controls. Exposure levels by task were predicted based on the median reported duration by activity, the year 1998, absence of source control methods, and an equal distribution of the other determinants of exposure. The model containing all the variables explained 60% of the variability and was identified as the best approximating model. Of the 27 tasks contained in the data set, abrasive blasting, masonry chipping, scabbling concrete, tuck pointing, and tunnel boring had estimated geometric means above 0.1mg m(-3) based on the exposure scenario developed. Water-fed tools and local exhaust ventilation were associated with a reduction of 71 and 69% in exposure levels compared with no controls, respectively. The predictive model developed can be used to estimate RCS concentrations for many construction activities in a wide range of circumstances. PMID:23223272

  4. Comparison of task-based exposure metrics for an epidemiologic study of isocyanate inhalation exposures among autobody shop workers.

    PubMed

    Woskie, Susan R; Bello, Dhimiter; Gore, Rebecca J; Stowe, Meredith H; Eisen, Ellen A; Liu, Youcheng; Sparer, Judy A; Redlich, Carrie A; Cullen, Mark R

    2008-09-01

    Because many occupational epidemiologic studies use exposure surrogates rather than quantitative exposure metrics, the UMass Lowell and Yale study of autobody shop workers provided an opportunity to evaluate the relative utility of surrogates and quantitative exposure metrics in an exposure response analysis of cross-week change in respiratory function. A task-based exposure assessment was used to develop several metrics of inhalation exposure to isocyanates. The metrics included the surrogates, job title, counts of spray painting events during the day, counts of spray and bystander exposure events, and a quantitative exposure metric that incorporated exposure determinant models based on task sampling and a personal workplace protection factor for respirator use, combined with a daily task checklist. The result of the quantitative exposure algorithm was an estimate of the daily time-weighted average respirator-corrected total NCO exposure (microg/m(3)). In general, these four metrics were found to be variable in agreement using measures such as weighted kappa and Spearman correlation. A logistic model for 10% drop in FEV(1) from Monday morning to Thursday morning was used to evaluate the utility of each exposure metric. The quantitative exposure metric was the most favorable, producing the best model fit, as well as the greatest strength and magnitude of association. This finding supports the reports of others that reducing exposure misclassification can improve risk estimates that otherwise would be biased toward the null. Although detailed and quantitative exposure assessment can be more time consuming and costly, it can improve exposure-disease evaluations and is more useful for risk assessment purposes. The task-based exposure modeling method successfully produced estimates of daily time-weighted average exposures in the complex and changing autobody shop work environment. The ambient TWA exposures of all of the office workers and technicians and 57% of the painters were found to be below the current U.K. Health and Safety Executive occupational exposure limit (OEL) for total NCO of 20 microg/m(3). When respirator use was incorporated, all personal daily exposures were below the U.K. OEL. PMID:18615291

  5. Computerized Task-Based Exposure, Explicitness, Type of Feedback, and Spanish L2 Development

    ERIC Educational Resources Information Center

    Rosa, Elena M.; Leow, Ronald P.

    2004-01-01

    This study examined whether exposure to second/foreign language (L2) data under different computerized task conditions had a differential impact on learners' ability to recognize and produce the target structure immediately after exposure to the input and over time. Learners' L2 development was assessed through recognition and…

  6. Effects of noise exposure and task demand on cardiovascular function.

    PubMed

    Wu, T N; Huang, J T; Chou, P F; Chang, P Y

    1988-01-01

    Cardiovascular effects under various noise-exposure and task-demand conditions were studied among 40 senior highschool students. The subjects consisted of 20 males and 20 females with a mean age of 16.7 +/- 0.7 years. All subjects had equivalent abacus performance ratings. Each subject was tested with a random sequence of six sessions. The time limit set for each session was 33 min. Six experimental sessions were constructed by a random combination of noise exposure (60, 85 or 90 dB (A] white noise) and task demand (task presence or task absence) variables. Blood pressure measures were taken at the beginning and ending phases of each session. A task-demand variable was defined as a conjoint of mental arithmetic (3 min) and abacus arithmetic (30 min). The results from the present study show that the effect of noise exposure on task performance is remarkable. Only noise exposure tended to influence the performance of male students in abacus arithmetic. The effect of task demand on blood pressure was higher than that of noise exposure. No interaction effect (noise exposure x task demand) on blood pressure, was found via analyses of within-subjects two-way ANOVA. PMID:3346087

  7. Hexavalent chromium exposure and control in welding tasks.

    PubMed

    Meeker, John D; Susi, Pam; Flynn, Michael R

    2010-11-01

    Studies of exposure to the lung carcinogen hexavalent chromium (CrVI) from welding tasks are limited, especially within the construction industry where overexposure may be common. In addition, despite the OSHA requirement that the use of engineering controls such as local exhaust ventilation (LEV) first be considered before relying on other strategies to reduce worker exposure to CrVI, data on the effectiveness of LEV to reduce CrVI exposures from welding are lacking. The goal of the present study was to characterize breathing zone air concentrations of CrVI during welding tasks and primary contributing factors in four datasets: (1) OSHA compliance data; (2) a publicly available database from The Welding Institute (TWI); (3) field survey data of construction welders collected by the Center for Construction Research and Training (CPWR); and (4) controlled welding trials conducted by CPWR to assess the effectiveness of a portable LEV unit to reduce CrVI exposure. In the OSHA (n = 181) and TWI (n = 124) datasets, which included very few samples from the construction industry, the OSHA permissible exposure level (PEL) for CrVI (5 μg/m(3)) was exceeded in 9% and 13% of samples, respectively. CrVI concentrations measured in the CPWR field surveys (n = 43) were considerably higher, and 25% of samples exceeded the PEL. In the TWI and CPWR datasets, base metal, welding process, and LEV use were important predictors of CrVI concentrations. Only weak-to-moderate correlations were found between total particulate matter and CrVI, suggesting that total particulate matter concentrations are not a good surrogate for CrVI exposure in retrospective studies. Finally, in the controlled welding trials, LEV reduced median CrVI concentrations by 68% (p = 0.02). In conclusion, overexposure to CrVI in stainless steel welding is likely widespread, especially in certain operations such as shielded metal arc welding, which is commonly used in construction. However, exposure could be substantially reduced with proper use of LEV. PMID:20845207

  8. Mentalization of complex emotions in borderline personality disorder: The impact of parenting and exposure to trauma on the performance in a novel cartoon-based task.

    PubMed

    Brüne, Martin; Walden, Sarah; Edel, Marc-Andreas; Dimaggio, Giancarlo

    2016-01-01

    Borderline personality disorder (BPD) is characterized by a range of interpersonal difficulties, which are, in part, related to adverse experiences during childhood. Unresponsive parenting and traumatization may cause functional impairment of mentalization, i.e. the ability to reflect upon own and others' mental states. However, the relationship of poor parenting, trauma and mentalization in BPD has not exhaustively been studied. Thirty patients diagnosed with BPD and 30 matched control subjects were asked to sequence a novel cartoon-based mentalization task involving complex emotions such as jealousy, shame, guilt etc. In addition, they were required to reason about cognitive and affective mental states of the cartoon characters. The quality of parental care was assessed using a self-report measure for recalled parental rearing style, and childhood trauma was measured in retrospect using the Childhood Trauma Questionnaire. Patients with BPD performed more poorly in all aspects of the cartoon task. Mentalizing skills, particularly relating to affective mental states, were uniquely associated with the quality of recalled parental care and childhood trauma. Together, the quality of parental care and the experience of childhood trauma negatively impact on mentalization in BPD, even in an experimental "offline" task. PMID:26350276

  9. Pilot task-based assessment of noise levels among firefighters

    PubMed Central

    Neitzel, RL; Hong, O; Quinlan, P; Hulea, R

    2012-01-01

    PURPOSE Over one million American firefighters are routinely exposed to various occupational hazards agents. While efforts have been made to identify and reduce some causes of injuries and illnesses among firefighters, relatively little has been done to evaluate and understand occupational noise exposures in this group. The purpose of this pilot study was to apply a task-based noise exposure assessment methodology to firefighting operations to evaluate potential noise exposure sources, and to use collected task-based noise levels to create noise exposure estimates for evaluation of risk of noise-induced hearing loss by comparison to the 8-hr and 24-hr recommended exposure limits (RELs) for noise of 85 and 80.3 dBA, respectively. METHODS Task-based noise exposures (n=100 measurements) were measured in three different fire departments (a rural department in Southeast Michigan and suburban and urban departments in Northern California). These levels were then combined with time-at-task information collected from firefighters to estimate 8-hr noise exposures for the rural and suburban fire departments (n=6 estimates for each department). Data from 24-hr dosimetry measurements and crude self-reported activity categories from the urban fire department (n=4 measurements) were used to create 24-hr exposure estimates to evaluate the bias associated with the task-based estimates. RESULTS Task-based noise levels were found to range from 82–109 dBA, with the highest levels resulting from use of saws and pneumatic chisels. Some short (e.g., 30 min) sequences of common tasks were found to result in nearly an entire allowable daily exposure. The majority of estimated 8-hr and 24-hr exposures exceeded the relevant recommended exposure limit. Predicted 24-hr exposures showed substantial imprecision in some cases, suggesting the need for increased task specificity. CONCLUSIONS The results indicate potential for overexposure to noise from a variety of firefighting tasks and equipment, and suggest a need for further exposure characterization and additional hearing loss prevention efforts. RELEVANCE TO INDUSTRY Firefighters may be at risk of noise-induced hearing loss, which can affect their fitness for duty and ability to respond effectively to emergencies. The results of this study suggest that additional efforts at hearing loss prevention among firefighters are warranted. PMID:24443622

  10. Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study

    PubMed Central

    2010-01-01

    Background A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Methods Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC) generated during the tasks were measured using a direct reading instrument (DRI) with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Results Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred during mirror cleaning. Conclusions Our results indicate that airborne exposures from short-term cleaning tasks can remain in the air even after tasks' cessation, suggesting potential exposures to anyone entering the room shortly after cleaning. Additionally, 2-BE concentrations from cleaning could approach occupational exposure limits and warrant further investigation. Measurement methods applied in this study can be useful for workplace assessment of airborne exposures during cleaning, if the limitations identified here are addressed. PMID:21118559

  11. Task-Based Information Searching.

    ERIC Educational Resources Information Center

    Vakkari, Pertti

    2003-01-01

    Reviews studies on the relationship between task performance and information searching by end-users, focusing on information searching in electronic environments and information retrieval systems. Topics include task analysis; task characteristics; search goals; modeling information searching; modeling search goals; information seeking behavior;

  12. Task-Based Information Searching.

    ERIC Educational Resources Information Center

    Vakkari, Pertti

    2003-01-01

    Reviews studies on the relationship between task performance and information searching by end-users, focusing on information searching in electronic environments and information retrieval systems. Topics include task analysis; task characteristics; search goals; modeling information searching; modeling search goals; information seeking behavior;…

  13. A task-specific assessment of Swine worker exposure to airborne dust.

    PubMed

    O'Shaughnessy, Patrick T; Donham, Kelley J; Peters, Thomas M; Taylor, Craig; Altmaier, Ralph; Kelly, Kevin M

    2010-01-01

    A task-based analysis of personal airborne dust exposures was performed in two swine confinement facilities used to house sows and their litters. Airborne particulate levels were assessed during summer, winter, and spring. Personal aerosol measurements of workers were made with a photometer every 15 sec and corrected to compare with an integrated concentration measurement made with a co-located IOM inhalable dust sampler. Task type and time period were recorded by the workers over an 8-hr work shift. There was a significant difference in dust concentrations between seasons (p < 0.001), with winter months providing the highest levels (geometric mean = 3.76 mg/m(3)). The application of a general linear model of log-transformed task concentrations relative to site, season, and task demonstrated significant differences (P < 0.001) among all three covariates. Tasks performed near moving animals, especially the weaning process, resulted in the greatest concentrations. These results indicate the need to evaluate the concentration levels for separate tasks during multi-task work shifts, such as swine rearing, to optimize efforts to minimize exposures by focusing on high-concentration tasks. PMID:19904655

  14. In-Session Exposure Tasks and Therapeutic Alliance across the Treatment of Childhood Anxiety Disorders

    ERIC Educational Resources Information Center

    Kendall, Philip C.; Comer, Jonathan S.; Marker, Craig D.; Creed, Torrey A.; Puliafico, Anthony C.; Hughes, Alicia A.; Martin, Erin D.; Suveg, Cynthia; Hudson, Jennifer

    2009-01-01

    The study examined the shape of therapeutic alliance using latent growth curve modeling and data from multiple informants (therapist, child, mother, father). Children (n = 86) with anxiety disorders were randomized to family-based cognitive-behavioral treatment (FCBT; N = 47) with exposure tasks or to family education, support, and attention…

  15. In-Session Exposure Tasks and Therapeutic Alliance across the Treatment of Childhood Anxiety Disorders

    ERIC Educational Resources Information Center

    Kendall, Philip C.; Comer, Jonathan S.; Marker, Craig D.; Creed, Torrey A.; Puliafico, Anthony C.; Hughes, Alicia A.; Martin, Erin D.; Suveg, Cynthia; Hudson, Jennifer

    2009-01-01

    The study examined the shape of therapeutic alliance using latent growth curve modeling and data from multiple informants (therapist, child, mother, father). Children (n = 86) with anxiety disorders were randomized to family-based cognitive-behavioral treatment (FCBT; N = 47) with exposure tasks or to family education, support, and attention

  16. Task-Based Instruction Using the Internet.

    ERIC Educational Resources Information Center

    Tumposky, Nancy Rennau

    This paper describes the design and implementation of an English as a Foreign Language (EFL) task-based module consistent with Skehan's information processing model of second language acquisition (1998) and with the framework for task design elaborated by Willis (1996), using the Internet as a primary source of language input. In settings where…

  17. Task based synthesis of serial manipulators

    PubMed Central

    Patel, Sarosh; Sobh, Tarek

    2015-01-01

    Computing the optimal geometric structure of manipulators is one of the most intricate problems in contemporary robot kinematics. Robotic manipulators are designed and built to perform certain predetermined tasks. There is a very close relationship between the structure of the manipulator and its kinematic performance. It is therefore important to incorporate such task requirements during the design and synthesis of the robotic manipulators. Such task requirements and performance constraints can be specified in terms of the required end-effector positions, orientations and velocities along the task trajectory. In this work, we present a comprehensive method to develop the optimal geometric structure (DH parameters) of a non-redundant six degree of freedom serial manipulator from task descriptions. In this work we define, develop and test a methodology to design optimal manipulator configurations based on task descriptions. This methodology is devised to investigate all possible manipulator configurations that can satisfy the task performance requirements under imposed joint constraints. Out of all the possible structures, the structures that can reach all the task points with the required orientations are selected. Next, these candidate structures are tested to see whether they can attain end-effector velocities in arbitrary directions within the user defined joint constraints, so that they can deliver the best kinematic performance. Additionally least power consuming configurations are also identified. PMID:26257946

  18. Exploring physical exposures and identifying high-risk work tasks within the floor layer trade

    PubMed Central

    McGaha, Jamie; Miller, Kim; Descatha, Alexis; Welch, Laurie; Buchholz, Bryan; Evanoff, Bradley; Dale, Ann Marie

    2014-01-01

    Introduction Floor layers have high rates of musculoskeletal disorders yet few studies have examined their work exposures. This study used observational methods to describe physical exposures within floor laying tasks. Methods We analyzed 45 videos from 32 floor layers using Multimedia-Video Task Analysis software to determine the time in task, forces, postures, and repetitive hand movements for installation of four common flooring materials. We used the WISHA checklists to define exposure thresholds. Results Most workers (91%) met the caution threshold for one or more exposures. Workers showed high exposures in multiple body parts with variability in exposures across tasks and for different materials. Prolonged exposures were seen for kneeling, poor neck and low back postures, and intermittent but frequent hand grip forces. Conclusions Floor layers experience prolonged awkward postures and high force physical exposures in multiple body parts, which probably contribute to their high rates of musculoskeletal disorders. PMID:24274895

  19. Safety-Seeking and Coping Behavior during Exposure Tasks with Anxious Youth

    ERIC Educational Resources Information Center

    Hedtke, Kristina A.; Kendall, Philip C.; Tiwari, Shilpee

    2009-01-01

    This study examined child behavior during exposure tasks and characteristics of the exposure tasks as related to outcomes when treating anxious youth. Participants (aged 7-13) were 87 anxiety-disordered children (37 girls; 50 boys) and their parents (84 mothers; 70 fathers) who completed a 16-session cognitive-behavioral therapy. Videotapes of…

  20. Task simulation in computer-based training

    SciTech Connect

    Gardner, P.R.

    1988-02-01

    Westinghouse Hanford Company (WHC) makes extensive use of job-task simulations in company-developed computer-based training (CBT) courseware. This courseware is different from most others because it does not simulate process control machinery or other computer programs, instead the WHC Excerises model day-to-day tasks such as physical work preparations, progress, and incident handling. These Exercises provide a higher level of motivation and enable the testing of more complex patterns of behavior than those typically measured by multiple-choice and short questions. Examples from the WHC Radiation Safety and Crane Safety courses will be used as illustrations. 3 refs.

  1. TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA

    SciTech Connect

    Miller, William A; Cheng, Mengdawn; New, Joshua Ryan; Ronnen, Levinson; Akbari, Hashem; Berhahl, Paul

    2010-03-01

    Airborne particulate matter that settles on a roof can either reflect or absorb incoming solar radiation, dependent on the chemical content and size of the particles. These light scattering and absorption processes occur within a few microns of the surface, and can affect the solar reflectance of the roof. Wilkes et al. (2000) tested 24 different roof coatings on a low-slope test stand and observed about a 25% decrease in the solar reflectance of white-coated and aluminum-coated surfaces as the time of exposure increased; however, the decrease leveled off after 2 years. SPRI Inc. and its affiliates studied the effect of climatic exposure on the surface properties of white thermoplastic single-ply membranes and determined that membranes lose from 30 to 50% of their reflectance over 3 years (Miller et al. 2002). The CMRC and its affiliates AISI, NamZAC, MBMA, MCA and NCCA exposed unpainted and painted metal roofing on both steep- and low-slope test roofs and found that after 3 years, the painted polyvinylidene fluoride (PVDF) metal roofs lost less than 5% of their original reflectance (Miller et al. 2004). The results of the three different weathering studies are very interesting in terms of their solar reflectance after 3 years of exposure. The white thermoplastic membrane and white ceramic coating with white topcoat had original reflectance measures that were about 20 percentage points higher than the painted metal; however, after 3-years of field exposure the solar reflectance of the painted metal exceeds that of the thermoplastic membrane and equals that of the coating. The long-term loss of reflectance appears driven by the ability of the particulate matter to cling to the roof and resist being washed off by wind and or rain. Miller et al. (2002) discovered that aerosol deposition introduced biomass of complex microbial consortia onto the test roofs and the combination of contaminants and biomass accelerated the loss of solar reflectance for the thermoplastic membranes and the roof coatings. Airborne contaminants and biomass were also detected on the painted metal roofs; however, the loss of solar reflectance was less than 5% for the painted metal roofs. The chemistry of the PVDF paint resin system uses similar organic film bonding to that responsible for Teflon , making it extremely chemical resistant and dirt shedding. Miller and Rudolph (2003) found the PVDF painted metals maintained solar reflectance even after 30 years of climatic exposure. Therefore the reduction of roof reflectance is closely related to the composition of the roof and to the chemical profile of the contaminants soiling the roof. Contaminants collected from samples of roof products exposed at seven California weathering sites were analyzed for elements and carbons to characterize the chemical profile of the particles soiling each roof sample and to identify those elements that degrade or enhance solar reflectance. The losses in solar reflectance varied from site to site and also varied at a give site based on the color of the coupon. The least drop in reflectance was observed in the alpine climate of McArthur while the largest drop occurred in sites near urban development. Light color samples were soiled after just one year of exposure. The darker color coupons did not show the same seasonal variations in solar reflectance as observed for the lighter colors. However, after an additional year of exposure the samples at all sites regained most of their solar reflectance due to rain and/or wind washing. The loss of reflectance appears cyclical with the onset of seasons having more rainfall. Solar reflectance of the cool pigmented coupons always exceeded that of the conventional pigmented coupons. Climatic soiling did not cause the cool pigmented roof coupons to lose any more solar reflectance than their conventional pigmented counterparts. The effect of roof slope appears to have more of an effect on lighter color roofs whose solar reflectance exceeds at least 0.5 and visually shows the accumulation of airborne contaminants. The thermal emittance remained invariant with time and location and was therefore not affected by climatic soiling. A thin-film deposition model was developed based on first principles, which simulates light interaction with a soiled substrate. This model was used in combination with the measured data to determine the solar absorptance and reflectance of particulate matter at each of the sites calculated using least squares fitting routines. Principal Component Analysis was used to determine the most important combinations of chemicals correlated with changes in solar absorption. Linear regression helped extract an approximate correlation using chromium, iron and elemental carbon concentrations. It appears that chromium ranks first, iron ranks second, and elemental carbon ranks third in importance to soil absorptance in the data

  2. Tool and Task Analysis Guide for Vocational Welding (150 Tasks). Performance Based Vocational Education.

    ERIC Educational Resources Information Center

    John H. Hinds Area Vocational School, Elwood, IN.

    This book contains a task inventory, a task analysis of 150 tasks from that inventory, and a tool list for performance-based welding courses in the state of Indiana. The task inventory and tool list reflect 28 job titles found in Indiana. In the first part of the guide, tasks are listed by these domains: carbon-arc, electron beam, G.M.A.W., gas…

  3. Binding Task-Based Language Teaching and Task-Based Language Testing: A Survey into EFL Teachers and Learners' Views of Task-Based Approach

    ERIC Educational Resources Information Center

    Panahi, Ali

    2012-01-01

    In most settings, task-based language teaching and testing have been dissociated from each other. That is why this study came to rethink of the learners' views towards awareness and implementation of task-based language teaching through IELTS listening tasks. To these objectives, after sketching instrumentation, the learners were divided into…

  4. Promoting Discourse with Task-Based Scenario Interaction.

    ERIC Educational Resources Information Center

    Dinapoli, Russell

    Tasks have become an essential feature of second language (L2) learning in recent years. Tasks range from getting learners to repeat linguistic elements satisfactorily to having them perform in "free" production. Along this task-based continuum, task-based scenario interaction lies at the point midway between controlled and semi-controlled…

  5. Characterization of occupational exposures to cleaning products used for common cleaning tasks-a pilot study of hospital cleaners

    PubMed Central

    2009-01-01

    Background In recent years, cleaning has been identified as an occupational risk because of an increased incidence of reported respiratory effects, such as asthma and asthma-like symptoms among cleaning workers. Due to the lack of systematic occupational hygiene analyses and workplace exposure data, it is not clear which cleaning-related exposures induce or aggravate asthma and other respiratory effects. Currently, there is a need for systematic evaluation of cleaning products ingredients and their exposures in the workplace. The objectives of this work were to: a) identify cleaning products' ingredients of concern with respect to respiratory and skin irritation and sensitization; and b) assess the potential for inhalation and dermal exposures to these ingredients during common cleaning tasks. Methods We prioritized ingredients of concern in cleaning products commonly used in several hospitals in Massachusetts. Methods included workplace interviews, reviews of product Materials Safety Data Sheets and the scientific literature on adverse health effects to humans, reviews of physico-chemical properties of cleaning ingredients, and occupational hygiene observational analyses. Furthermore, the potential for exposure in the workplace was assessed by conducting qualitative assessment of airborne exposures and semi-quantitative assessment of dermal exposures. Results Cleaning products used for common cleaning tasks were mixtures of many chemicals, including respiratory and dermal irritants and sensitizers. Examples of ingredients of concern include quaternary ammonium compounds, 2-butoxyethanol, and ethanolamines. Cleaning workers are at risk of acute and chronic inhalation exposures to volatile organic compounds (VOC) vapors and aerosols generated from product spraying, and dermal exposures mostly through hands. Conclusion Cleaning products are mixtures of many chemical ingredients that may impact workers' health through air and dermal exposures. Because cleaning exposures are a function of product formulations and product application procedures, a combination of product evaluation with workplace exposure assessment is critical in developing strategies for protecting workers from cleaning hazards. Our task based assessment methods allowed classification of tasks in different exposure categories, a strategy that can be employed by epidemiological investigations related to cleaning. The methods presented here can be used by occupational and environmental health practitioners to identify intervention strategies. PMID:19327131

  6. Characterizing Task-Based OpenMP Programs

    PubMed Central

    Muddukrishna, Ananya; Jonsson, Peter A.; Brorsson, Mats

    2015-01-01

    Programmers struggle to understand performance of task-based OpenMP programs since profiling tools only report thread-based performance. Performance tuning also requires task-based performance in order to balance per-task memory hierarchy utilization against exposed task parallelism. We provide a cost-effective method to extract detailed task-based performance information from OpenMP programs. We demonstrate the utility of our method by quickly diagnosing performance problems and characterizing exposed task parallelism and per-task instruction profiles of benchmarks in the widely-used Barcelona OpenMP Tasks Suite. Programmers can tune performance faster and understand performance tradeoffs more effectively than existing tools by using our method to characterize task-based performance. PMID:25860023

  7. Task based weights for spectral computed tomography

    NASA Astrophysics Data System (ADS)

    Yveborg, Moa; Danielsson, Mats; Bornefalk, Hans

    2012-03-01

    In photon counting multi-bin CT, both projection based weighting and image based weighting (designed to maximize the signal-difference-to-noise ratio SDNR) in the final image, are pixel based and do not account for any spatial frequency dependency of signal and noise among the bins. The same weighting scheme will be used when imaging objects with a large fraction of high spatial frequencies and those with predominantly low spatial frequency content. Any effect on the detectability of a certain target due to correlation between detector elements and bins that might arise in pulse height discriminating systems will not be captured using such an approach. We show how to take the spatial frequency dependency of signal and noise transfer for each bin, and the spatial frequency composition of a target, into account when determining optimal task based weights for photon-counting multi-bin CT imaging using the 2D slice detectability index by applying cascaded system analysis to a spectrally resolved photon counting CT detector system with multiple bins.

  8. A task exposure database for use in the alumina and primary aluminium industry.

    PubMed

    Benke, G; Sim, M; Fritschi, L; Aldred, G

    2001-02-01

    A task exposure database (TED) was developed to facilitate data collation for construction of a task exposure matrix (TEM) for Healthwise, a series of studies on cancer and respiratory morbidity in the alumina and primary aluminium industry. Following the construction of job classifications for the eight study sites, the site hygienists identified all historical air monitoring time-weighted average (TWA) data, from their respective sites. The earliest data were sampled in the late 1970s, and over 17,000 personal samples were recorded over the eight sites over a twenty-year period. TED, a Microsoft Access database, was developed for use by site occupational hygienists to collate these exposure data across the mines, refineries and smelters. All data conforming to strict criteria for use were recorded using TED and provided to the study group. Following the individual data point entry, a calculator program in TED systematically calculated the geometric means, arithmetic means, and maximum and minimum results at the task level. Other features of TED included fields for flagging "significant changes" and "stepwise changes" in exposure. TED established a standardised means of data collation that later formed the basis for the construction of a TEM for the study. A TEM is similar to a job exposure matrix (JEM) except that the basic unit of categorization is at the task level instead of at the job level. Both a TEM and JEM have been constructed independently for Healthwise. The possible reduction of exposure misclassification and improvement in validity of exposure characterization with the use of the TEM, is currently under investigation. The Healthwise TEM consists of annual TWA and peak data results for each site for various airborne contaminants, including fluorides, coal tar pitch volatiles, sulfur dioxide, inspirable dust, alumina dust, bauxite dust, and oil mist. Construction of the TEM for the Healthwise study was completed in late 1998 and consists of over 33,700 TWA years of task exposure data. PMID:11217702

  9. Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training.

    PubMed

    Cong, Lin-Juan; Wang, Ru-Jie; Yu, Cong; Zhang, Jun-Yun

    2016-02-01

    Visual perceptual learning is known to be specific to the trained retinal location, feature, and task. However, location and feature specificity can be eliminated by double-training or TPE training protocols, in which observers receive additional exposure to the transfer location or feature dimension via an irrelevant task besides the primary learning task Here we tested whether these new training protocols could even make learning transfer across different tasks involving discrimination of basic visual features (e.g., orientation and contrast). Observers practiced a near-threshold orientation (or contrast) discrimination task. Following a TPE training protocol, they also received exposure to the transfer task via performing suprathreshold contrast (or orientation) discrimination in alternating blocks of trials in the same sessions. The results showed no evidence for significant learning transfer to the untrained near-threshold contrast (or orientation) discrimination task after discounting the pretest effects and the suprathreshold practice effects. These results thus do not support a hypothetical task-independent component in perceptual learning of basic visual features. They also set the boundary of the new training protocols in their capability to enable learning transfer. PMID:26873777

  10. Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training

    PubMed Central

    Cong, Lin-Juan; Wang, Ru-Jie; Yu, Cong; Zhang, Jun-Yun

    2016-01-01

    Visual perceptual learning is known to be specific to the trained retinal location, feature, and task. However, location and feature specificity can be eliminated by double-training or TPE training protocols, in which observers receive additional exposure to the transfer location or feature dimension via an irrelevant task besides the primary learning task Here we tested whether these new training protocols could even make learning transfer across different tasks involving discrimination of basic visual features (e.g., orientation and contrast). Observers practiced a near-threshold orientation (or contrast) discrimination task. Following a TPE training protocol, they also received exposure to the transfer task via performing suprathreshold contrast (or orientation) discrimination in alternating blocks of trials in the same sessions. The results showed no evidence for significant learning transfer to the untrained near-threshold contrast (or orientation) discrimination task after discounting the pretest effects and the suprathreshold practice effects. These results thus do not support a hypothetical task-independent component in perceptual learning of basic visual features. They also set the boundary of the new training protocols in their capability to enable learning transfer. PMID:26873777

  11. Integration of Task-Based Approaches in a TESOL Course

    ERIC Educational Resources Information Center

    Chien, Chin-Wen

    2014-01-01

    Under task-based language teaching (TBLT), language learners engage in purposeful, problem-oriented, and outcome-driven tasks that are comparable to real-world activities. This qualitative case study discusses the integration of a task-based approach into a TESOL course in a language teacher education program in Taiwan with regard to 39…

  12. Sex Differences in Task Distribution and Task Exposures among Danish House Painters: An Observational Study Combining Questionnaire Data with Biomechanical Measurements

    PubMed Central

    Heilskov-Hansen, Thomas; Wulff Svendsen, Susanne; Frølund Thomsen, Jane; Mikkelsen, Sigurd; Hansson, Gert-Åke

    2014-01-01

    Objectives Sex differences in occupational biomechanical exposures may be part of the explanation why musculoskeletal complaints and disorders tend to be more common among women than among men. We aimed to determine possible sex differences in task distribution and task-specific postures and movements of the upper extremities among Danish house painters, and to establish sex-specific task exposure matrices. Methods To obtain task distributions, we sent out a questionnaire to all members of the Painters' Union in Denmark (N = 9364), of whom 53% responded. Respondents reported their task distributions in a typical week. To obtain task exposures, postures and movements were measured in 25 male and 25 female house painters for one whole working day per person. We used goniometers on the wrists, and inclinometers on the forehead and the upper arms. Participants filled in a logbook allowing task-specific exposures to be identified. Percentiles and % time with non-neutral postures were used to characterise postures. Velocity, range of motion, repetitiveness, and variation were used as measures of movement. Cochran-Mantel-Haenszel statistics and unpaired double-sided t-tests with post-hoc Bonferroni correction were used to evaluate sex differences. Results Statistically significant (p<0.05) sex differences were revealed in task proportions, but the proportions differed by less than 4%. For task exposures, no statistically significant sex differences were found. Conclusions Only minor sex differences were found in task distribution and task exposures regarding postures and movements among Danish house painters. Sex-specific task exposure matrices were established. PMID:25365301

  13. Preventing skin cancer: findings of the Task Force on Community Preventive Services On reducing Exposure to Ultraviolet Light.

    PubMed

    Saraiya, Mona; Glanz, Karen; Briss, Peter; Nichols, Phyllis; White, Cornelia; Das, Debjani

    2003-10-17

    Rates of skin cancer, the most common cancer in the United States, are increasing. The most preventable risk factor for skin cancer is unprotected ultraviolet (UV) exposure. Seeking to identify effective approaches to reducing the incidence of skin cancer by improving individual and community efforts to reduce unprotected UV exposure, the Task Force on Community Preventive Services conducted systematic reviews of community interventions to reduce exposure to ultraviolet light and increase protective behaviors. The Task Force found sufficient evidence to recommend two interventions that are based on improvements in sun protective or "covering-up" behavior (wearing protective clothing including long-sleeved clothing or hats): educational and policy approaches in two settings--primary schools and recreational or tourism sites. They found insufficient evidence to determine the effectiveness of a range of other population-based interventions and recommended additional research in these areas: educational and policy approaches in child care centers, secondary schools and colleges, recreational or tourism sites for children, and workplaces; interventions conducted in health-care settings and targeted to both providers and children's parents or caregivers; media campaigns alone; and community wide multicomponent interventions. This report also presents additional information regarding the recommended community interventions, briefly describes how the reviews were conducted, provides resources for further information, and provides information that can help in applying the interventions locally. The U.S. Preventive Services Task Force conducted a systematic review of counseling by primary care clinicians to prevent skin cancer (CDC. Counseling to prevent skin cancer: recommendation and rationale of the U.S. Preventive Services Task Force. MMWR 2003;52[No. RR-15]:13-17), which is also included in this issue, the first jointly released findings from the Task Force on Community Preventive Services and the U.S. Preventive Services Task Force. PMID:14561953

  14. A Blended Learning Study on Implementing Video Recorded Speaking Tasks in Task-Based Classroom Instruction

    ERIC Educational Resources Information Center

    Kirkgoz, Yasemin

    2011-01-01

    This study investigates designing and implementing a speaking course in which face-to-face instruction informed by the principles of Task-Based Learning is blended with the use of technology, the video, for the first-year student teachers of English in Turkish higher education. The study consisted of three hours of task-based classroom…

  15. Dental Aide: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Newport News Public Schools, VA.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the dental aide program. Section 1 contains a validated task inventory for dental aide. For each task, applicable information pertaining to performance and enabling objectives, criterion-referenced…

  16. Bilingual Children's Acquisition of English Verb Morphology: Effects of Language Exposure, Structure Complexity, and Task Type

    ERIC Educational Resources Information Center

    Paradis, Johanne

    2010-01-01

    This study investigated whether bilingual-monolingual differences would be apparent in school-age children's use and knowledge of English verb morphology and whether differences would be influenced by amount of exposure to English, complexity of the morphological structure, or the type of task given. French-English bilinguals (mean age = 6;10)…

  17. Using Goal Setting and Task Analysis to Enhance Task-Based Language Learning and Teaching

    ERIC Educational Resources Information Center

    Rubin, Joan

    2015-01-01

    Task-Based Language Learning and Teaching has received sustained attention from teachers and researchers for over thirty years. It is a well-established pedagogy that includes the following characteristics: major focus on authentic and real-world tasks, choice of linguistic resources by learners, and a clearly defined non-linguistic outcome. This…

  18. Applications of Task-Based Learning in TESOL

    ERIC Educational Resources Information Center

    Shehadeh, Ali, Ed.; Coombe, Christine, Ed.

    2010-01-01

    Why are many teachers around the world moving toward task-based learning (TBL)? This shift is based on the strong belief that TBL facilitates second language acquisition and makes second language learning and teaching more principled and effective. Based on insights gained from using tasks as research tools, this volume shows how teachers can use

  19. Applications of Task-Based Learning in TESOL

    ERIC Educational Resources Information Center

    Shehadeh, Ali, Ed.; Coombe, Christine, Ed.

    2010-01-01

    Why are many teachers around the world moving toward task-based learning (TBL)? This shift is based on the strong belief that TBL facilitates second language acquisition and makes second language learning and teaching more principled and effective. Based on insights gained from using tasks as research tools, this volume shows how teachers can use…

  20. Ordering Design Tasks Based on Coupling Strengths

    NASA Technical Reports Server (NTRS)

    Rogers, J. L.; Bloebaum, C. L.

    1994-01-01

    The design process associated with large engineering systems requires an initial decomposition of the complex system into modules of design tasks which are coupled through the transference of output data. In analyzing or optimizing such a coupled system, it is essential to be able to determine which interactions figure prominently enough to significantly affect the accuracy of the system solution. Many decomposition approaches assume the capability is available to determine what design tasks and interactions exist and what order of execution will be imposed during the analysis process. Unfortunately, this is often a complex problem and beyond the capabilities of a human design manager. A new feature for DeMAID (Design Manager's Aid for Intelligent Decomposition) will allow the design manager to use coupling strength information to find a proper sequence for ordering the design tasks. In addition, these coupling strengths aid in deciding if certain tasks or couplings could be removed (or temporarily suspended) from consideration to achieve computational savings without a significant loss of system accuracy. New rules are presented and two small test cases are used to show the effects of using coupling strengths in this manner.

  1. Ordering design tasks based on coupling strengths

    NASA Technical Reports Server (NTRS)

    Rogers, James L., Jr.; Bloebaum, Christina L.

    1994-01-01

    The design process associated with large engineering systems requires an initial decomposition of the complex system into modules of design tasks which are coupled through the transference of output data. In analyzing or optimizing such a coupled system, it is essential to be able to determine which interactions figure prominently enough to significantly affect the accuracy of the system solution. Many decomposition approaches assume the capability is available to determine what design tasks and interactions exist and what order of execution will be imposed during the analysis process. Unfortunately, this is often a complex problem and beyond the capabilities of a human design manager. A new feature for DeMAID (Design Manager's Aid for Intelligent Decomposition) will allow the design manager to use coupling strength information to find a proper sequence for ordering the design tasks. In addition, these coupling strengths aid in deciding if certain tasks or couplings could be removed (or temporarily suspended) from consideration to achieve computational savings without a significant loss of system accuracy. New rules are presented and two small test cases are used to show the effects of using coupling strengths in this manner.

  2. Task-Based Variability in Children's Singing Accuracy

    ERIC Educational Resources Information Center

    Nichols, Bryan E.

    2013-01-01

    The purpose of this study was to explore task-based variability in children's singing accuracy performance. The research questions were: Does children's singing accuracy vary based on the nature of the singing assessment employed? Is there a hierarchy of difficulty and discrimination ability among singing assessment tasks? What is the

  3. Current Task-Based Language Teaching: Some Issues and Models.

    ERIC Educational Resources Information Center

    Brown, Steven

    This paper examines disagreement over how second language learning tasks create conditions needed for language acquisition by exploring and comparing three second language acquisition theories: input-based; output-based; and interactionist. Each theory is described, and some new conclusions are drawn. It is argued that a task should: be…

  4. Task-Based Variability in Children's Singing Accuracy

    ERIC Educational Resources Information Center

    Nichols, Bryan E.

    2013-01-01

    The purpose of this study was to explore task-based variability in children's singing accuracy performance. The research questions were: Does children's singing accuracy vary based on the nature of the singing assessment employed? Is there a hierarchy of difficulty and discrimination ability among singing assessment tasks? What is the…

  5. An Agent-Based Cockpit Task Management System

    NASA Technical Reports Server (NTRS)

    Funk, Ken

    1997-01-01

    An agent-based program to facilitate Cockpit Task Management (CTM) in commercial transport aircraft is developed and evaluated. The agent-based program called the AgendaManager (AMgr) is described and evaluated in a part-task simulator study using airline pilots.

  6. Occupational exposure to electric fields and currents associated with 110 kV substation tasks.

    PubMed

    Korpinen, Leena H; Kuisti, Harri A; Tarao, Hiroo; Elovaara, Jarmo A

    2012-07-01

    The main aim of this study was to investigate occupational exposure to electric fields, and current densities and contact currents associated with tasks at air-insulated 110 kV substations and analyze if the action value of EU Directive 2004/40/EC was exceeded. Four workers volunteered to simulate the following tasks: Task (A) maintenance of an operating device of a disconnector at ground or floor level, Task (B) maintenance of an operating device of a circuit breaker at ground or floor level, Task (C) breaker head maintenance from a man hoist, and Task (D) maintenance of an operating device of a circuit breaker from a service platform. The highest maximum average current density in the neck was 1.8 mA/m(2) (calculated internal electric field 9.0-18.0 mV/m) and the highest contact current was 79.4 µA. All measured values at substations were lower than the limit value (10 mA/m(2)) of the EU Directive 2004/40/EC and the 2010 basic restrictions (0.1 and 0.8 V/m for central nervous system tissues of the head, and all tissues of the head and body, respectively) of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). PMID:22334373

  7. The activation of semantic memory: effects of prime exposure, prime-target relationship, and task demands.

    PubMed

    Bueno, Steve; Frenck-Mestre, Cheryl

    2008-06-01

    Priming facilitation was examined under conditions of brief incremental prime exposures (28, 43, 71, and 199 msec) under masked conditions for two types of lexical relationships (associative-semantic pairs, such as "wolf-fox," and semantic-feature pairs, such as "whale-dolphin") and in two tasks (primed lexical decision and semantic categorization). The results of eight experiments revealed, first, that priming elicits faster response times for semantic-feature pairs. The associative-semantic pairs produced priming only at the longer prime exposures. Second, priming was observed earlier for semantic categorization than for the lexical decision task, in which priming was observed only at the longer stimulus onset asynchronies. Finally, our results allowed us to discredit the congruency hypothesis, according to which priming is due to a common categorical response for the prime and target words. The implications of these results for current theories of semantic priming are discussed. PMID:18604969

  8. The role of task interference and exposure duration in judging noise annoyance

    NASA Astrophysics Data System (ADS)

    Zimmer, Karin; Ghani, Jody; Ellermeier, Wolfgang

    2008-04-01

    To determine whether the amount of performance disruption by a noise has an effect on the annoyance that noise evokes, a laboratory situation was created in which the participants rated a number of sounds before, after, and while performing a cognitively demanding memory task. The task consisted of memorizing, and later reproducing, a visually presented sequence of digits while being exposed to irrelevant sound chosen to produce different degrees of disruption. In two experiments, participants assessed these background sounds (frequency-modulated tones, broadband noise and speech) on a rating scale consisting of thirteen categories ranging from 'not annoying at all' to 'extremely annoying.' The judgments were collected immediately before, after, and concomitant to, the memory task. The results of the first experiment (N=24) showed that the annoyance assessments were indeed altered by the experience of disruption, most strongly during, and to a lesser extent after task completion, whereas ratings of the non-disruptive sounds remained largely unaffected. In the second experiment (N=25), participants were exposed to the same sounds, but for longer intervals at a time: 10 min as opposed to 14 s in the first experiment. The longer exposure resulted in increased annoyance in all noise conditions, but did not alter the differential effect of disruption on annoyance, which was replicated. The results of these laboratory experiments support the notion that annoyance cannot be conceived of as a purely perceptual sound property; rather, it is influenced by the degree of interference with the task at hand.

  9. Task Listing for Respiratory Therapy Assistant. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    This instructional task listing is designed to be used in combination with the "Health Occupations Education Service Area Resource" in order to implement competency-based education in the respiratory therapy assistant program in Virginia. The task listing contains three major sections: (1) duty areas; (2) a program description; and (3) a content…

  10. Vietnamese Children and Language-Based Processing Tasks

    ERIC Educational Resources Information Center

    Hwa-Froelich, Deborah A.; Matsuo, Hisako

    2005-01-01

    Purpose: Vietnamese children's performance on language-based processing tasks of fast-mapping (FM) word-learning and dynamic assessment (DA) word- and rule-learning tasks were investigated. Method: Twenty-one first- and second-generation Vietnamese preschool children participated in this study. All children were enrolled in 2 Head Start programs…

  11. Designing Digital Problem Based Learning Tasks that Motivate Students

    ERIC Educational Resources Information Center

    van Loon, Anne-Marieke; Ros, Anje; Martens, Rob

    2013-01-01

    This study examines whether teachers are able to apply the principles of autonomy support and structure support in designing digital problem based learning (PBL) tasks. We examine whether these tasks are more autonomy- and structure-supportive and whether primary and secondary school students experience greater autonomy, competence, and motivation…

  12. Vietnamese Children and Language-Based Processing Tasks

    ERIC Educational Resources Information Center

    Hwa-Froelich, Deborah A.; Matsuo, Hisako

    2005-01-01

    Purpose: Vietnamese children's performance on language-based processing tasks of fast-mapping (FM) word-learning and dynamic assessment (DA) word- and rule-learning tasks were investigated. Method: Twenty-one first- and second-generation Vietnamese preschool children participated in this study. All children were enrolled in 2 Head Start programs

  13. The Video-Based Short Comment Writing Task

    ERIC Educational Resources Information Center

    Pino-Silva, Juan

    2007-01-01

    Composing from sources may no longer be the exclusive domain of reading-to-write activities. The ever-increasing presence of video technology and broadcasting in academic settings could place listening-to-write tasks on a similar footing. This article describes a listening-to-write task, the video-based short comment, which (1) uses video as…

  14. A Guide to Task Analysis for Competency Based Education. Health Occupations. Task Linkage Project Publication No. 4.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta. School of Education.

    Developed through synthesis and review of existing task analysis literature, this guide lists tasks expected to be performed by workers in ten health occupations and presents information for incorporating these tasks into articulated secondary and postsecondary competency based educational programs. Task listings are presented for the following…

  15. Exploring the effects of seated whole body vibration exposure on repetitive asymmetric lifting tasks.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J; Sommerich, Carolyn M

    2015-01-01

    This study investigated changes in the physiological and behavioral responses to repetitive asymmetric lifting activity after exposure to whole body vibrations. Seventeen healthy volunteers repeatedly lifted a box (15% of lifter's capacity) positioned in front of them at ankle level to a location on their left side at waist level at the rate of 10 lifts/min for a period of 60 minutes. Prior to lifting, participants were seated on a vibrating platform for 60 minutes; in one of the two sessions the platform did not vibrate. Overall, the physiological responses assessed using near-infrared spectroscopy signals for the erector spinae muscles decreased significantly over time during the seating and the lifting tasks (p < 0.001). During repetitive asymmetric lifting, behavioral changes included increases in peak forward bending motion, twisting movement, and three-dimensional movement velocities of the spine. The lateral bending movement of the spine and the duration of each lift decreased significantly over the 60 minutes of repetitive lifting. With exposure to whole body vibration, participants twisted farther (p = 0.046) and twisted faster (p = 0.025). These behavioral changes would suggest an increase in back injury risk when repetitive lifting tasks are preceded by whole body vibration exposure. PMID:25264920

  16. A Python-based IRAF Task Parameter Editor

    NASA Astrophysics Data System (ADS)

    de La Peña, M. D.

    As part of the development of a new Python-based CL for IRAF tasks by the Science Software Group at STScI, we have developed a GUI-based parameter editor for IRAF tasks using Tkinter. This new parameter editor is intended to provide the equivalent functionality of the IRAF EPAR task, but to make parameter editing easier by using appropriate user interface elements, such as menu choice lists, action buttons, and file browsers. This paper describes the design and functionality of the parameter editor as well as planned enhancements.

  17. Tinkering with Tasks Knows No Bounds: ESL Teachers' Adaptations of Task-Based Language-Teaching

    ERIC Educational Resources Information Center

    Plews, John L.; Zhao, Kangxian

    2010-01-01

    Research on implementing task-based language-teaching (TBLT) shows that adapting TBLT in ways that are inconsistent with its principles is common among nonnative-speaker English-as-a-foreign-language teachers. Our study of Canadian native-speaker English-as-a-second language teachers reveals how they also adapt TBLT in ways that are incongruent…

  18. Task Delegation Based Access Control Models for Workflow Systems

    NASA Astrophysics Data System (ADS)

    Gaaloul, Khaled; Charoy, Franois

    e-Government organisations are facilitated and conducted using workflow management systems. Role-based access control (RBAC) is recognised as an efficient access control model for large organisations. The application of RBAC in workflow systems cannot, however, grant permissions to users dynamically while business processes are being executed. We currently observe a move away from predefined strict workflow modelling towards approaches supporting flexibility on the organisational level. One specific approach is that of task delegation. Task delegation is a mechanism that supports organisational flexibility, and ensures delegation of authority in access control systems. In this paper, we propose a Task-oriented Access Control (TAC) model based on RBAC to address these requirements. We aim to reason about task from organisational perspectives and resources perspectives to analyse and specify authorisation constraints. Moreover, we present a fine grained access control protocol to support delegation based on the TAC model.

  19. Task-Based Flocking Algorithm for Mobile Robot Cooperation

    NASA Astrophysics Data System (ADS)

    He, Hongsheng; Ge, Shuzhi Sam; Tong, Guofeng

    In this paper, one task-based flocking algorithm that coordinates a swarm of robots is presented and evaluated based on the standard simulation platform. Task-based flocking algorithm(TFA) is an effective framework for mobile robots cooperation. Flocking behaviors are integrated into the cooperation of the multi-robot system to organize a robot team to achieve a common goal. The goal of the whole team is obtained through the collaboration of the individual robot’s task. The flocking model is presented, and the flocking energy function is defined based on that model to analyze the stability of the flocking and the task switching criterion. The simulation study is conducted in a five-versus-five soccer game, where the each robot dynamically selects its task in accordance with status and the whole robot team behaves as a flocking. Through simulation results and experiments, it is proved that the task-based flocking algorithm can effectively coordinate and control the robot flock to achieve the goal.

  20. Enhanced multi-task compressive sensing using Laplace priors and MDL-based task classification

    NASA Astrophysics Data System (ADS)

    Wang, Ying-Gui; Yang, Le; Tang, Liang; Liu, Zheng; Jiang, Wen-Li

    2013-12-01

    In multi-task compressive sensing (MCS), the original signals of multiple compressive sensing (CS) tasks are assumed to be correlated. This is explored to recover signals in a joint manner to improve signal reconstruction performance. In this paper, we first develop an improved version of MCS that imposes sparseness over the original signals using Laplace priors. The newly proposed technique, termed as the Laplace prior-based MCS (LMCS), adopts a hierarchical prior model, and the MCS is shown analytically to be a special case of LMCS. This paper next considers the scenario where the CS tasks belong to different groups. In this case, the original signals from different task groups are not well correlated, which would degrade the signal recovery performance of both MCS and LMCS. We propose the use of the minimum description length (MDL) principle to enhance the MCS and LMCS techniques. New algorithms, referred to as MDL-MCS and MDL-LMCS, are developed. They first classify tasks into different groups and then reconstruct signals from each cluster jointly. Simulations demonstrate that the proposed algorithms have better performance over several state-of-art benchmark techniques.

  1. Teachers' teaching practices and beliefs regarding context-based tasks and their relation with students' difficulties in solving these tasks

    NASA Astrophysics Data System (ADS)

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-12-01

    In this study, we investigated teachers' teaching practices and their underlying beliefs regarding context-based tasks to find a possible explanation for students' difficulties with these tasks. The research started by surveying 27 Junior High School teachers from seven schools in Indonesia through a written questionnaire. Then, to further examine teachers' teaching practices related to context-based tasks, four teachers were observed and video recorded in two mathematics lessons in which they were asked to deal with context-based tasks. The questionnaire data revealed that the teachers had a tendency toward a view on teaching and learning mathematics which includes encouraging students to be actively involved in solving problems in various contexts. Although this finding suggests that the teachers may offer opportunities to learn context-based tasks to students, the questionnaire data also revealed that the teachers saw context-based tasks as plain word problems. Furthermore, the observations disclosed that their teaching was mainly teacher-centered and directive, which is not considered to be supportive for learning to solve context-based tasks. Combining the findings of this study with the results from our earlier study on Indonesian students' errors when solving context-based tasks, we found a relationship between how Indonesian teachers teach context-based tasks and the errors Indonesian students make in solving these tasks. These findings support the conclusion that insufficient opportunity-to-learn to solve context-based tasks offered by teachers is a possible explanation for students' difficulties in solving these tasks.

  2. Enhancing speech learning by combining task practice with periods of stimulus exposure without practice.

    PubMed

    Wright, Beverly A; Baese-Berk, Melissa M; Marrone, Nicole; Bradlow, Ann R

    2015-08-01

    Language acquisition typically involves periods when the learner speaks and listens to the new language, and others when the learner is exposed to the language without consciously speaking or listening to it. Adaptation to variants of a native language occurs under similar conditions. Here, speech learning by adults was assessed following a training regimen that mimicked this common situation of language immersion without continuous active language processing. Experiment 1 focused on the acquisition of a novel phonetic category along the voice-onset-time continuum, while Experiment 2 focused on adaptation to foreign-accented speech. The critical training regimens of each experiment involved alternation between periods of practice with the task of phonetic classification (Experiment 1) or sentence recognition (Experiment 2) and periods of stimulus exposure without practice. These practice and exposure periods yielded little to no improvement separately, but alternation between them generated as much or more improvement as did practicing during every period. Practice appears to serve as a catalyst that enables stimulus exposures encountered both during and outside of the practice periods to contribute to quite distinct cases of speech learning. It follows that practice-plus-exposure combinations may tap a general learning mechanism that facilitates language acquisition and speech processing. PMID:26328708

  3. Classroom Writing Tasks and Students' Analytic Text-Based Writing

    ERIC Educational Resources Information Center

    Matsumura, Lindsay Clare; Correnti, Richard; Wang, Elaine

    2015-01-01

    The Common Core State Standards emphasize students writing analytically in response to texts. Questions remain about the nature of instruction that develops students' text-based writing skills. In the present study, we examined the role that writing task quality plays in students' mastery of analytic text-based writing. Text-based writing tasks…

  4. A Multiagent Recommender System with Task-Based Agent Specialization

    NASA Astrophysics Data System (ADS)

    Lorenzi, Fabiana; Correa, Fabio Arreguy Camargo; Bazzan, Ana L. C.; Abel, Mara; Ricci, Francesco

    This paper describes a multiagent recommender system where agents maintain local knowledge bases and, when requested to support a travel planning task, they collaborate exchanging information stored in their local bases. A request for a travel recommendation is decomposed by the system into sub tasks, corresponding to travel services. Agents select tasks autonomously, and accomplish them with the help of the knowledge derived from previous solutions. In the proposed architecture, agents become experts in some task types, and this makes the recommendation generation more efficient. In this paper, we validate the model via simulations where agents collaborate to recommend a travel package to the user. The experiments show that specialization is useful hence providing a validation of the proposed model.

  5. Task-based working memory guidance of visual attention.

    PubMed

    Chen, Zhe; Tsou, Brian H

    2011-05-01

    Previous research has established that holding a stimulus in working memory (WM) facilitates the deployment of visual attention to that stimulus relative to other stimuli. The present study examined whether maintaining a specific task in WM would also bias the allocation of attention to the stimuli associated with that task. Participants performed a speeded letter search task while simultaneously keeping in WM one of two task cues shown at the beginning of each trial. The results showed that task-based WM guidance of attention was modulated by response latencies. Whereas the participants with fast reaction times showed little influence of WM contents, the participants with slow reaction times took longer to respond when the letter target appeared in a distractor stimulus consistent with the task cue held in mind. A subsequent Stroop experiment found a larger Stroop interference effect from the participants in the slow group compared with those in the fast group, suggesting that the differential WM effect between the two groups may be associated with an individual's ability to inhibit task-irrelevant information. Taken together, these results expanded the realm of previous research and provided further evidence for a close link between attention and WM. PMID:21264740

  6. Effects on automatic attention due to exposure to pictures of emotional faces while performing Chinese word judgment tasks.

    PubMed

    Junhong, Huang; Renlai, Zhou; Senqi, Hu

    2013-01-01

    Two experiments were conducted to investigate the automatic processing of emotional facial expressions while performing low or high demand cognitive tasks under unattended conditions. In Experiment 1, 35 subjects performed low (judging the structure of Chinese words) and high (judging the tone of Chinese words) cognitive load tasks while exposed to unattended pictures of fearful, neutral, or happy faces. The results revealed that the reaction time was slower and the performance accuracy was higher while performing the low cognitive load task than while performing the high cognitive load task. Exposure to fearful faces resulted in significantly longer reaction times and lower accuracy than exposure to neutral faces on the low cognitive load task. In Experiment 2, 26 subjects performed the same word judgment tasks and their brain event-related potentials (ERPs) were measured for a period of 800 ms after the onset of the task stimulus. The amplitudes of the early component of ERP around 176 ms (P2) elicited by unattended fearful faces over frontal-central-parietal recording sites was significantly larger than those elicited by unattended neutral faces while performing the word structure judgment task. Together, the findings of the two experiments indicated that unattended fearful faces captured significantly more attention resources than unattended neutral faces on a low cognitive load task, but not on a high cognitive load task. It was concluded that fearful faces could automatically capture attention if residues of attention resources were available under the unattended condition. PMID:24124486

  7. EFL Reading Instruction: Communicative Task-Based Approach

    ERIC Educational Resources Information Center

    Sidek, Harison Mohd

    2012-01-01

    The purpose of this study was to examine the overarching framework of EFL (English as a Foreign Language) reading instructional approach reflected in an EFL secondary school curriculum in Malaysia. Based on such analysis, a comparison was made if Communicative Task-Based Language is the overarching instructional approach for the Malaysian EFL…

  8. An ontology-based telemedicine tasks management system architecture.

    PubMed

    Nageba, Ebrahim; Fayn, Jocelyne; Rubel, Paul

    2008-01-01

    The recent developments in ambient intelligence and ubiquitous computing offer new opportunities for the design of advanced Telemedicine systems providing high quality services, anywhere, anytime. In this paper we present an approach for building an ontology-based task-driven telemedicine system. The architecture is composed of a task management server, a communication server and a knowledge base for enabling decision makings taking account of different telemedical concepts such as actors, resources, services and the Electronic Health Record. The final objective is to provide an intelligent management of the different types of available human, material and communication resources. PMID:19162954

  9. POPULATION-BASED EXPOSURE AND DOSE MODELING FOR AIR POLLUTANTS

    EPA Science Inventory

    This task will address EPA's need to better understand the variability in personal exposure to air pollutants for the purpose of assessing what populations are at risk for adverse health outcomes due to air pollutant exposures. To improve our understanding of exposures to air po...

  10. The Campus-Based Formula. NASFAA Task Force Report

    ERIC Educational Resources Information Center

    National Association of Student Financial Aid Administrators, 2014

    2014-01-01

    The primary purpose of the National Association of Student Financial Aid Administrators (NASFAA) Campus-Based Aid Allocation Task Force was to examine the formula by which congressional appropriations for the Federal Supplemental Educational Opportunity Grant (FSEOG), Federal Work-Study (FWS), and Perkins Loan programs are distributed to schools,…

  11. Mother Tongue Use in Task-Based Language Teaching Model

    ERIC Educational Resources Information Center

    Hung, Nguyen Viet

    2012-01-01

    Researches of English language teaching (ELT) have focused on using mother tongue (L1) for years. The proliferation of task-based language teaching (TBLT) has been also occurred. Considerable findings have been made in the existing literature of the two fields; however, no mentions have been made in the combination of these two ELT aspects, i.e.,…

  12. 3Ps, Task-Based Learning, and the Japanese Learner.

    ERIC Educational Resources Information Center

    Tanasarnsanee, Mika

    2002-01-01

    Summarizes the findings of a work in progress that attempted to investigate to what extent task-based learning was more effective than the 3Ps approach in the teaching of Japanese as a foreign language in Thailand. (Author/VWL)

  13. Task-Based Language Teaching and Expansive Learning Theory

    ERIC Educational Resources Information Center

    Robertson, Margaret

    2014-01-01

    Task-Based Language Teaching (TBLT) has become increasingly recognized as an effective pedagogy, but its location in generalized sociocultural theories of learning has led to misunderstandings and criticism. The purpose of this article is to explain the congruence between TBLT and Expansive Learning Theory and the benefits of doing so. The merit…

  14. Implementing Task-Based Learning with Young Learners.

    ERIC Educational Resources Information Center

    Carless, David

    2002-01-01

    Draws on qualitative classroom observation data from case studies of three English-as-a-Foreign-Language classes in Hong Kong primary schools. Analyzes four themes relevant to the classroom implementation of task-based learning with young learners: noise/in discipline, use of the mother tongue, extent of pupil involvement, and the role of drawing…

  15. Strategy Training in a Task-Based Language Classroom

    ERIC Educational Resources Information Center

    Lai, Chun; Lin, Xiaolin

    2015-01-01

    Recent literature that examines the implementation of task-based language teaching (TBLT) in classroom settings has reported various challenges related to educational cultures, classroom management, teacher cognition and learner perceptions. To facilitate the smooth transition of TBLT from laboratory settings to classroom contexts, measures need…

  16. An exposure indicator for digital radiography: AAPM Task Group 116 (Executive Summary)

    SciTech Connect

    Shepard, S. Jeff; Wang Jihong; Flynn, Michael; and others

    2009-07-15

    Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

  17. An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).

    PubMed

    Shepard, S Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E

    2009-07-01

    Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines. PMID:19673189

  18. An exposure indicator for digital radiography: AAPM Task Group 116 (Executive Summary)

    PubMed Central

    Shepard, S. Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L.; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E.

    2009-01-01

    Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines. PMID:19673189

  19. A task-based metric for telerobotic performance assessment

    NASA Technical Reports Server (NTRS)

    Barnes, J. F.

    1987-01-01

    A methodology is described for developing a task complexity index based on combining the six basic motion primitives (three translation, three orientation) with force control and accuracy requirements. The result of this development is a set of complexity values that can be assigned to the high-level task primitives derived from a relatively shallow top-down mission analysis. These values are then averaged to arrive at total average mission complexities, such as for the mission of exchanging the Hubble Space Telescope (HST) battery modules. Application of this metric to a candidate set of NASA Flight Telerobotic Servicer evaluation tasks is discussed using the HST battery module mission for an in-depth example.

  20. POPULATION-BASED EXPOSURE MODELING FOR AIR POLLUTANTS AT EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY

    EPA Science Inventory

    The US EPA's National Exposure Research Laboratory (NERL) has been developing, applying, and evaluating population-based exposure models to improve our understanding of the variability in personal exposure to air pollutants. Estimates of population variability are needed for E...

  1. Task-based optimization of image reconstruction in breast CT

    NASA Astrophysics Data System (ADS)

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2014-03-01

    We demonstrate a task-based assessment of image quality in dedicated breast CT in order to optimize the number of projection views acquired. The methodology we employ is based on the Hotelling Observer (HO) and its associated metrics. We consider two tasks: the Rayleigh task of discerning between two resolvable objects and a single larger object, and the signal detection task of classifying an image as belonging to either a signalpresent or signal-absent hypothesis. HO SNR values are computed for 50, 100, 200, 500, and 1000 projection view images, with the total imaging radiation dose held constant. We use the conventional fan-beam FBP algorithm and investigate the effect of varying the width of a Hanning window used in the reconstruction, since this affects both the noise properties of the image and the under-sampling artifacts which can arise in the case of sparse-view acquisitions. Our results demonstrate that fewer projection views should be used in order to increase HO performance, which in this case constitutes an upper-bound on human observer performance. However, the impact on HO SNR of using fewer projection views, each with a higher dose, is not as significant as the impact of employing regularization in the FBP reconstruction through a Hanning filter.

  2. Assessing task compliance following mobile phone-based video reminders.

    PubMed

    O'Neill, Sonja A; Parente, Guido; Donnelly, Mark P; Nugent, Chris D; Beattie, Mark P; McClean, Sally I; Scotney, Bryan W; Mason, Sarah C; Craig, David

    2011-01-01

    In the development of technology for people with mild dementia it is essential to achieve a combination of the features which provide both support and monitoring along with the ability to offer a level of personalization. Reminding support by means of personalized video reminders portraying a relative or friend combined with sensors to assess whether the requested task was performed lends itself as an ideal combination to achieve this aim. This study assesses the potential of using low cost, off the shelf sensors combined with a mobile phone-based video reminding system to assess compliance with task completion. A validation study has been conducted in a lab-based environment with 10 healthy young participants. The work presented discusses the implementation of the approach adopted, data analysis of the results attained along with outlining future developments of this approach. PMID:22255533

  3. Prototype Videodisk-Based Part-Task Thermal Imaging Trainer

    NASA Technical Reports Server (NTRS)

    Brickner, Michael S.; Foyle, David C.; Sridhar, Banavar (Technical Monitor)

    1995-01-01

    Thermal images, or infrared images, are representations of the world based on heat, instead of visible light. Research has shown that the resulting thermal image results in perceptual differences leading to difficulties in interpretation (e.g., the determination of slope angle, concavity/convexity), or increased identification latencies. A joint research project between the United States (NASA and U.S. Army) and Israel (Ministry of Defense and Israel Air Force) has resulted in the development of a prototype part-task trainer for the acquisition of perceptual skills associated with thermal imaging usage. This prototype system is videodisk-based under computer control, using recordings of thermal images. A lesson section introduces declarative knowledge, in which the basic physics and heuristics of thermal imagery are taught. An exercise section teaches procedural knowledge, with the user viewing dynamic, actual imagery, with an interactive detection/location determination task. The general philosophy and design of the trainer will be demonstrated.

  4. Task-based assessment and optimization of digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Young, Stefano

    Digital breast tomosynthesis (DBT) is a new technology for breast cancer screening that promises to complement mammography or supersede it to become the standard for breast imaging. DBT involves taking multiple images in order to synthesize a new image that represents a slice through the breast volume---hence the term tomosynthesis. The primary advantage of this paradigm is that it can reduce the amount of overlapping anatomy in the data, leading to improved visualization of potentially-cancerous findings. The difficulty in DBT is quantifying the advantages of the technology and determining the optimal conditions for its clinical use. This dissertation describes a virtual trial framework for assessing and optimizing DBT technology for the specific task of detecting small, low-contrast masses in the breast. It addresses each component of the imaging chain to some degree, from the patients/phantoms to the imaging hardware to the model observers used to measure signal detectability. The main focus, however, is on quantifying tradeoffs between three key parameters that affect image quality: (1) scan angle, (2) number of projections, and (3) exposure. We show that in low-density breast phantoms, detectability generally increases with both scan angle and number of projections in the anatomical-variability-limited (high-exposure) regime. We also investigate how breast density affects the optimal DBT scan parameters. We show task-specific results that support using an adaptive paradigm in DBT, where the imaging system reconfigures itself in response to information about the patient's breast density. The virtual framework described in this dissertation provides a platform for further investigations of image quality in 3D breast imaging.

  5. Performance on a strategy set shifting task in rats following adult or adolescent cocaine exposure

    PubMed Central

    Kantak, Kathleen M.; Barlow, Nicole; Tassin, David H.; Brisotti, Madeline F.; Jordan, Chloe J

    2014-01-01

    Rationale Neuropsychological testing is widespread in adult cocaine abusers, but lacking in teens. Animal models may provide insight into age-related neuropsychological consequences of cocaine exposure. Objectives Determine whether developmental plasticity protects or hinders behavioral flexibility after cocaine exposure in adolescent vs. adult rats. Methods Using a yoked-triad design, one rat controlled cocaine delivery and the other two passively received cocaine or saline. Rats controlling cocaine delivery (1.0 mg/kg) self-administered for 18 sessions (starting P37 or P77), followed by 18 drug-free days. Rats next were tested in a strategy set shifting task, lasting 11–13 sessions. Results Cocaine self-administration did not differ between age groups. During initial set formation, adolescent-onset groups required more trials to reach criterion and made more errors than adult-onset groups. During the set shift phase, rats with adult-onset cocaine self-administration experience had higher proportions of correct trials and fewer perseverative + regressive errors than age-matched yoked-controls or rats with adolescent-onset cocaine self-administration experience. During reversal learning, rats with adult-onset cocaine experience (self-administered or passive) required fewer trials to reach criterion and the self-administering rats made fewer perseverative + regressive errors than yoked-saline rats. Rats receiving adolescent-onset yoked-cocaine had more trial omissions and longer lever press reaction times than age-matched rats self-administering cocaine or receiving yoked-saline. Conclusions Prior cocaine self-administration may impair memory to reduce proactive interference during set shifting and reversal learning in adult-onset but not adolescent-onset rats (developmental plasticity protective). Passive cocaine may disrupt aspects of executive function in adolescent-onset but not adult-onset rats (developmental plasticity hinders). PMID:24800898

  6. The Task Is Not Enough: Processing Approaches to Task-Based Performance

    ERIC Educational Resources Information Center

    Skehan, Peter; Xiaoyue, Bei; Qian, Li; Wang, Zhan

    2012-01-01

    This article reports on three research studies, all of which concern second language task performance. The first focuses on planning, and compares on-line and strategic planning as well as task repetition. The second study examines the role of familiarity on task performance, and compares this with conventional strategic planning. The third study…

  7. Promoting Task-Based Pragmatics Instruction in EFL Classroom Contexts: The Role of Task Complexity

    ERIC Educational Resources Information Center

    Kim, Youjin; Taguchi, Naoko

    2015-01-01

    Robinson's (2001) Cognition Hypothesis claims that more complex tasks promote interaction and language development. This study examined the effect of task complexity in the learning of request-making expressions. Task complexity was operationalized as [+/- reasoning] following Robinson's framework. The study employed a pretest-posttest research…

  8. The Effects of Multimedia Task-Based Language Teaching on EFL Learners' Oral L2 Production

    ERIC Educational Resources Information Center

    BavaHarji, Madhubala; Gheitanchian, Mehrnaz; Letchumanan, Krishnaveni

    2014-01-01

    This study examined the effects of tasks, with varying levels of complexity, i.e. simple, + complex and ++ complex tasks on EFL learners' oral production in a multimedia task-based language teaching environment. 57 EFL adult learners carried out a total of 12 tasks, in sets of four tasks within three different themes and different levels of…

  9. Teachers' Teaching Practices and Beliefs Regarding Context-Based Tasks and Their Relation with Students' Difficulties in Solving These Tasks

    ERIC Educational Resources Information Center

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-01-01

    In this study, we investigated teachers' teaching practices and their underlying beliefs regarding context-based tasks to find a possible explanation for students' difficulties with these tasks. The research started by surveying 27 Junior High School teachers from seven schools in Indonesia through a written questionnaire. Then, to further examine

  10. Teachers' Teaching Practices and Beliefs Regarding Context-Based Tasks and Their Relation with Students' Difficulties in Solving These Tasks

    ERIC Educational Resources Information Center

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-01-01

    In this study, we investigated teachers' teaching practices and their underlying beliefs regarding context-based tasks to find a possible explanation for students' difficulties with these tasks. The research started by surveying 27 Junior High School teachers from seven schools in Indonesia through a written questionnaire. Then, to further examine…

  11. Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

    NASA Technical Reports Server (NTRS)

    Spalding, J. F.; Holland, L. M.; Prine, J. R.; Farrer, D. N.; Braun, R. G.

    1972-01-01

    Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower.

  12. Emotion-based learning: insights from the Iowa Gambling Task

    PubMed Central

    Turnbull, Oliver H.; Bowman, Caroline H.; Shanker, Shanti; Davies, Julie L.

    2014-01-01

    Interest in the cognitive and/or emotional basis of complex decision-making, and the related phenomenon of emotion-based learning, has been heavily influenced by the Iowa Gambling Task. A number of psychological variables have been investigated as potentially important in understanding emotion-based learning. This paper reviews the extent to which humans are explicitly aware of how we make such decisions; the biasing influence of pre-existing emotional labels; and the extent to which emotion-based systems are anatomically and functionally independent of episodic memory. Review of literature suggests that (i) an aspect of conscious awareness does appear to be readily achieved during the IGT, but as a relatively unfocused emotion-based “gut-feeling,” akin to intuition; (ii) Several studies have manipulated the affective pre-loading of IGT tasks, and make it clear that such labeling has a substantial influence on performance, an experimental manipulation similar to the phenomenon of prejudice. (iii) Finally, it appears that complex emotion-based learning can remain intact despite profound amnesia, at least in some neurological patients, a finding with a range of potentially important clinical implications: in the management of dementia; in explaining infantile amnesia; and in understanding of the possible mechanisms of psychotherapy. PMID:24711796

  13. Task-based lens design with application to digital mammography

    PubMed Central

    Chen, Liying; Barrett, Harrison H.

    2006-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design. PMID:15669625

  14. The Effects of Study Tasks in a Computer-Based Chemistry Learning Environment

    ERIC Educational Resources Information Center

    Urhahne, Detlef; Nick, Sabine; Poepping, Anna Christin; Schulz , Sarah Jayne

    2013-01-01

    The present study examines the effects of different study tasks on the acquisition of knowledge about acids and bases in a computer-based learning environment. Three different task formats were selected to create three treatment conditions: learning with gap-fill and matching tasks, learning with multiple-choice tasks, and learning only from text…

  15. Task Selection, Task Switching and Multitasking during Computer-Based Independent Study

    ERIC Educational Resources Information Center

    Judd, Terry

    2015-01-01

    Detailed logs of students' computer use, during independent study sessions, were captured in an open-access computer laboratory. Each log consisted of a chronological sequence of tasks representing either the application or the Internet domain displayed in the workstation's active window. Each task was classified using a three-tier schema

  16. Task Selection, Task Switching and Multitasking during Computer-Based Independent Study

    ERIC Educational Resources Information Center

    Judd, Terry

    2015-01-01

    Detailed logs of students' computer use, during independent study sessions, were captured in an open-access computer laboratory. Each log consisted of a chronological sequence of tasks representing either the application or the Internet domain displayed in the workstation's active window. Each task was classified using a three-tier schema…

  17. The Task-Based Teaching of Writing to Big Classes in Chinese EFL Setting

    ERIC Educational Resources Information Center

    Hai-yan, Miao

    2014-01-01

    This paper explores how to teach English writing to big classes in China from the task-based perspective. Based on a comparison between the traditional 3Ps approach and the tasked-based approach, the paper proposes a practical linear procedure as to how to teach English writing in the task-based classroom to big classes. An empirical study is…

  18. Adolescent exposure to methylphenidate impairs serial pattern learning in the serial multiple choice (SMC) task in adult rats.

    PubMed

    Rowan, James D; McCarty, Madison K; Kundey, Shannon M A; Osburn, Crystal D; Renaud, Samantha M; Kelley, Brian M; Matoushek, Amanda Willey; Fountain, Stephen B

    2015-01-01

    The long-term effects of adolescent exposure to methylphenidate (MPD) on adult cognitive capacity are largely unknown. We utilized a serial multiple choice (SMC) task, which is a sequential learning paradigm for studying complex learning, to observe the effects of methylphenidate exposure during adolescence on later serial pattern acquisition during adulthood. Following 20.0mg/kg/day MPD or saline exposure for 5 days/week for 5 weeks during adolescence, male rats were trained to produce a highly structured serial response pattern in an octagonal operant chamber for water reinforcement as adults. During a transfer phase, a violation to the previously-learned pattern structure was introduced as the last element of the sequential pattern. Results indicated that while rats in both groups were able to learn the training and transfer patterns, adolescent exposure to MPD impaired learning for some aspects of pattern learning in the training phase which are learned using discrimination learning or serial position learning. In contrast adolescent exposure to MPD had no effect on other aspects of pattern learning which have been shown to tap into rule learning mechanisms. Additionally, adolescent MPD exposure impaired learning for the violation element in the transfer phase. This indicates a deficit in multi-item learning previously shown to be responsible for violation element learning. Thus, these results clearly show that adolescent MPD produced multiple cognitive impairments in male rats that persisted into adulthood long after MPD exposure ended. PMID:26225921

  19. Local search to improve coordinate-based task mapping

    SciTech Connect

    Balzuweit, Evan; Bunde, David P.; Leung, Vitus J.; Finley, Austin; Lee, Alan C. S.

    2015-10-31

    We present a local search strategy to improve the coordinate-based mapping of a parallel job’s tasks to the MPI ranks of its parallel allocation in order to reduce network congestion and the job’s communication time. The goal is to reduce the number of network hops between communicating pairs of ranks. Our target is applications with a nearest-neighbor stencil communication pattern running on mesh systems with non-contiguous processor allocation, such as Cray XE and XK Systems. Utilizing the miniGhost mini-app, which models the shock physics application CTH, we demonstrate that our strategy reduces application running time while also reducing the runtime variability. Furthermore, we further show that mapping quality can vary based on the selected allocation algorithm, even between allocation algorithms of similar apparent quality.

  20. Local search to improve coordinate-based task mapping

    DOE PAGESBeta

    Balzuweit, Evan; Bunde, David P.; Leung, Vitus J.; Finley, Austin; Lee, Alan C. S.

    2015-10-31

    We present a local search strategy to improve the coordinate-based mapping of a parallel job’s tasks to the MPI ranks of its parallel allocation in order to reduce network congestion and the job’s communication time. The goal is to reduce the number of network hops between communicating pairs of ranks. Our target is applications with a nearest-neighbor stencil communication pattern running on mesh systems with non-contiguous processor allocation, such as Cray XE and XK Systems. Utilizing the miniGhost mini-app, which models the shock physics application CTH, we demonstrate that our strategy reduces application running time while also reducing the runtimemore » variability. Furthermore, we further show that mapping quality can vary based on the selected allocation algorithm, even between allocation algorithms of similar apparent quality.« less

  1. Assessing the Ability of a VR-Based Assembly Task Simulation to Evaluate Physical Risk Factors.

    PubMed

    Pontonnier, Charles; Samani, Afshin; Badawi, Marwan; Madeleine, Pascal; Dumont, Georges

    2014-05-01

    Nowadays the process of workstation design tends to include assessment steps in a virtual environment (VE) to evaluate the ergonomic features. These approaches are cost-effective and convenient since working directly on the digital mock-up in a VE is preferable to constructing a real physical mock-up in a real environment (RE). This study aimed at understanding the ability of a VR-based assembly tasks simulator to evaluate physical risk factors in ergonomics. Sixteen subjects performed simplified assembly tasks in RE and VE. Motion of the upper body and five muscle electromyographic activities were recorded to compute normalized and averaged objective indicators of discomfort, that is, rapid upper limb assessment score, averaged muscle activations, and total task time. Rated perceived exertion (RPE) and a questionnaire were used as subjective indicators of discomfort. The timing regime and complexity of the assembly tasks were investigated as within-subject factors. The results revealed significant differences between measured indicators in RE and VE. While objective measures indicated lower activity and exposure in VE, the subjects experienced more discomfort than in RE. Fairly good correlation levels were found between RE and VE for six of the objective indicators. This study clearly demonstrates that ergonomic studies of assembly tasks using VR are still challenging. Indeed, objective and subjective measurements of discomfort that are usually used in ergonomics to minimize the risks of work-related musculoskeletal disorders development exhibit opposite trends in RE and VE. Nevertheless, the high level of correlation found during this study indicates that the VR-based simulator can be used for such assessments. PMID:26357290

  2. An Analysis of Teacher Defined Mathematical Tasks: Engaging Urban Learners in Performance-Based Instruction

    ERIC Educational Resources Information Center

    Thomas, Christine D.; Williams, Desha L.

    2008-01-01

    This is an investigation of secondary mathematics teachers' understanding of performance-based tasks with respect to the contextual design of tasks that promote urban students' engagement and pursuit in learning mathematical concepts. We examined the alignment of teacher designed tasks with their personal definitions of tasks; then further…

  3. Repeating Input-Based Tasks with Young Beginner Learners

    ERIC Educational Resources Information Center

    Shintani, Natsuko

    2012-01-01

    The study reported in this article investigated task-repetition with young Japanese children. Fifteen children with no prior knowledge of English completed a communicative listening task that was designed to introduce new vocabulary. The same task was repeated nine times over five weeks. In line with Allwright's (1984) claim that "interaction is…

  4. The Time on Task Effect in Reading and Problem Solving Is Moderated by Task Difficulty and Skill: Insights from a Computer-Based Large-Scale Assessment

    ERIC Educational Resources Information Center

    Goldhammer, Frank; Naumann, Johannes; Stelter, Annette; Tóth, Krisztina; Rölke, Heiko; Klieme, Eckhard

    2014-01-01

    Computer-based assessment can provide new insights into behavioral processes of task completion that cannot be uncovered by paper-based instruments. Time presents a major characteristic of the task completion process. Psychologically, time on task has 2 different interpretations, suggesting opposing associations with task outcome: Spending more…

  5. Obstetric Ultrasound Simulator With Task-Based Training and Assessment.

    PubMed

    Liu, Li; Kutarnia, Jason; Belady, Petra; Pedersen, Peder C

    2015-10-01

    The increasing use of point-of-care (POC) ultrasound presents a challenge in providing efficient training to POC ultrasound users for whom formal training is not readily available. In response to this need, we developed an affordable compact laptop-based obstetric ultrasound training simulator. It offers a realistic scanning experience, task-based training, and performance assessment. The position and orientation of the sham transducer are tracked with 5 DoF on an abdomen-sized scan surface with the shape of a cylindrical segment. On the simulator, user interface is rendered a virtual torso whose body surface models the abdomen of the pregnant scan subject. A virtual transducer scans the virtual torso by following the sham transducer movements on the scan surface. A given 3-D training image volume is generated by combining several overlapping 3-D ultrasound sweeps acquired from the pregnant scan subject using a Markov random field-based approach. Obstetric ultrasound training is completed through a series of tasks, guided by the simulator and focused on three aspects: basic medical ultrasound, orientation to obstetric space, and fetal biometry. The scanning performance is automatically evaluated by comparing user-identified anatomical landmarks with reference landmarks preinserted by sonographers. The simulator renders 2-D ultrasound images in real time with 30 frames/s or higher with good image quality; the training procedure follows standard obstetric ultrasound protocol. Thus, for learners without access to formal sonography programs, the simulator is intended to provide structured training in basic obstetrics ultrasound. PMID:25993700

  6. Effects of sitting and standing on upper extremity physical exposures in materials handling tasks.

    PubMed

    Cudlip, Alan C; Callaghan, Jack P; Dickerson, Clark R

    2015-10-01

    Sitting or standing work configurations modulate musculoskeletal risk. Most existing investigations of these configurations have either studied them separately or lacked focus on the upper extremity, particularly during manual materials handling (MMH) tasks. To address this gap, upper extremity loading in 20 male and 20 females were assessed in 4 MMH tasks in sitting and standing. Differences in electromyographic (EMG) activity, local joint moments and body discomfort between configurations were examined. Interactions between task and sit/stand configuration resulted in increases of up to 500% in joint moments, 94% in EMG activity and 880% in discomfort when tasks were completed while sitting (p < 0.01). Future MMH task designers should consider placing workers in standing postures when feasible to reduce upper extremity loading, but workers should not remain in either configuration for extended periods of time as the negative effects of both workspace geometries can instigate future musculoskeletal disorders. Practitioner Summary: Sitting and standing modify occupational musculoskeletal risk. We examined how performing identical tasks while sitting or standing altered upper extremity and low back loading. In general, sitting increased muscle activity and discomfort, while standing increased local joint moments. The benefits of standing outweighed those of sitting across the range of tasks. PMID:25993653

  7. The nature of impulsivity: visual exposure to natural environments decreases impulsive decision-making in a delay discounting task.

    PubMed

    Berry, Meredith S; Sweeney, Mary M; Morath, Justice; Odum, Amy L; Jordan, Kerry E

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments. PMID:24841421

  8. Effects of repeated exposure to JP-8 jet fuel vapor on learning of simple and difficult operant tasks by rats.

    PubMed

    Ritchie, G D; Rossi, J; Nordholm, A F; Still, K R; Carpenter, R L; Wenger, G R; Wright, D W

    2001-11-01

    Groups of 16 Sprague-Dawley rats each were exposed by whole-body inhalation methods to JP-8 jet fuel at the highest vapor concentration without formation of aerosol (1,000 +/- 10% mg/m3); to 50% of this concentration (500 +/- 10% mg/m3); or to treated room air (70 +/- 81 L/min) for 6 h/d, 5 d/wk, for 6 wk (180 h). Although two subjects died of apparent kidney complications during the study, no other change in the health status of exposed rats was observed, including rate of weight gain. Following a 65-d period of rest, rats were evaluated for their capacity to learn and perform a series of operant tasks. These tasks ranged in difficulty from learning of a simple food-reinforced lever pressing response, to learning a task in which subjects were required to emit up to four-response chains of pressing three different levers (e.g., press levers C, R, L, then C). It was shown that repeated exposure to 1,000 mg/m3 JP-8 vapor induced significant deficits in acquisition or performance of moderately difficult or difficult tasks, but not simple learning tasks, as compared to those animals exposed to 500 mg/m3. Learning/performance of complex tasks by the 500-mg/m3 exposure group generally exceeded the performance of control animals, while learning by the 1,000-mg/m3 group was nearly always inferior to controls, indicating possible "neurobehavioral" hormesis. These findings appear consistent with some previously reported data for operant performance following acute exposure to certain hydrocarbon constituents of JP-8 (i.e., toluene, xylenes). There has, however, been little previously published research demonstrating long-term learning effects for repeated hydrocarbon fuel exposures. Examination of regional brain tissues from vapor-exposed rats indicated significant changes in levels of dopamine in the cerebral cortex and DOPAC in the brainstem, measured as long as 180 d postexposure, as compared to controls. PMID:11700005

  9. Cloud based toolbox for image analysis, processing and reconstruction tasks.

    PubMed

    Bednarz, Tomasz; Wang, Dadong; Arzhaeva, Yulia; Lagerstrom, Ryan; Vallotton, Pascal; Burdett, Neil; Khassapov, Alex; Szul, Piotr; Chen, Shiping; Sun, Changming; Domanski, Luke; Thompson, Darren; Gureyev, Timur; Taylor, John A

    2015-01-01

    This chapter describes a novel way of carrying out image analysis, reconstruction and processing tasks using cloud based service provided on the Australian National eResearch Collaboration Tools and Resources (NeCTAR) infrastructure. The toolbox allows users free access to a wide range of useful blocks of functionalities (imaging functions) that can be connected together in workflows allowing creation of even more complex algorithms that can be re-run on different data sets, shared with others or additionally adjusted. The functions given are in the area of cellular imaging, advanced X-ray image analysis, computed tomography and 3D medical imaging and visualisation. The service is currently available on the website www.cloudimaging.net.au . PMID:25381109

  10. Language Tasks Using Touch Screen and Mobile Technologies: Reconceptualizing Task-Based CALL for Young Language Learners

    ERIC Educational Resources Information Center

    Pellerin, Martine

    2014-01-01

    This article examines how the use of mobile technologies (iPods and tablets) in language classrooms contributes to redesigning task-based approaches for young language learners. The article is based on a collaborative action research (CAR) project in Early French Immersion classrooms in the province of Alberta, Canada. The data collection included…

  11. Paradoxical Effects of Injection Stress and Nicotine Exposure Experienced During Adolescence on Learning in a Serial Multiple Choice (SMC) Task in Adult Female Rats

    PubMed Central

    Renaud, Samantha M.; Pickens, Laura R. G.; Fountain, Stephen B.

    2015-01-01

    Nicotine exposure in adolescent rats has been shown to cause learning impairments that persist into adulthood long after nicotine exposure has ended. This study was designed to assess the extent to which the effects of adolescent nicotine exposure on learning in adulthood can be accounted for by adolescent injection stress experienced concurrently with adolescent nicotine exposure. Female rats received either 0.033 mg/hr nicotine (expressed as the weight of the free base) or bacteriostatic water vehicle by osmotic pump infusion on postnatal days 25-53 (P25-53). Half of the nicotine-exposed rats and half of the vehicle rats also received twice-daily injection stress consisting of intraperitoneal saline injections on P26-53. Together these procedures produced 4 groups: No Nicotine / No Stress, Nicotine / No Stress, No Nicotine / Stress, and Nicotine / Stress. On P65-99, rats were trained to perform a structurally complex 24-element serial pattern of responses in the serial multiple choice (SMC) task. Four general results were obtained in the current study. First, learning for within-chunk elements was not affected by either adolescent nicotine exposure, consistent with past work (Pickens, Rowan, Bevins, & Fountain, 2013), or adolescent injection stress. Thus, there were no effects of adolescent nicotine exposure or injection stress on adult within-chunk learning typically attributed to rule learning in the SMC task. Second, adolescent injection stress alone (i.e., without concurrent nicotine exposure) caused transient but significant facilitation of adult learning restricted to a single element of the 24-element pattern, namely, the “violation element,” that was the only element of the pattern that was inconsistent with pattern structure. Thus, adolescent injection stress alone facilitated violation element acquisition in adulthood. Third, also consistent with past work (Pickens et al., 2013), adolescent nicotine exposure, in this case both with and without adolescent injection stress, caused a learning impairment in adulthood for the violation element in female rats. Thus, adolescent nicotine impaired adult violation element learning typically attributed to multiple-item learning in the SMC task. Fourth, a paradoxical interaction of injection stress and nicotine exposure in acquisition was observed. In the same female rats in which violation-element learning was impaired by adolescent nicotine exposure, adolescent nicotine experienced without adolescent injection stress produced better learning for chunk-boundary elements in adulthood compared to all other conditions. Thus, adolescent nicotine without concurrent injection stress facilitated adult chunk-boundary element learning typically attributed to concurrent stimulus-response discrimination learning and serial-position learning in the SMC task. To the best of our knowledge, the current study is the first to demonstrate facilitation of adult learning caused by adolescent nicotine exposure. PMID:25527003

  12. Task Complexity, Focus on L2 Constructions, and Individual Differences: A Classroom-Based Study

    ERIC Educational Resources Information Center

    Revesz, Andrea

    2011-01-01

    Motivated by cognitive-interactionist frameworks for task-based learning, this study explores whether task complexity affects the extent to which learners focus on form-meaning connections during task-based work in a classroom setting, and whether this relationship is modulated by 3 individual difference factors--linguistic self-confidence,

  13. Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

    ERIC Educational Resources Information Center

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

    2014-01-01

    "Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external…

  14. Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

    ERIC Educational Resources Information Center

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

    2014-01-01

    "Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external

  15. Young Foreign Language Learners' Interactions during Task-Based Paired Assessments

    ERIC Educational Resources Information Center

    Butler, Yuko Goto; Zeng, Wei

    2014-01-01

    Despite the popularity of task-based language teaching (TBLT) in foreign language (FL) education at elementary school, it remains unclear how young learners' FL abilities can best be evaluated with tasks. The present study seeks to understand developmental differences in interactions among elementary-school students during task-based language…

  16. Task technical and QA plan: Thermal effects study: To evaluate saltstone properties associated with performance criteria as a function of extended exposure to temperatures typical of adiabatic curing

    SciTech Connect

    Orebaugh, E.G.

    1990-06-15

    The task to evaluate saltstone properties associated with performance criteria as a function of extended exposure to temperatures typical of adiabatic curing is described in this document and involves extension of previous qualification studies for DWPF Saltstone formulations.

  17. [The application of the concise exposure index to repetitive movement tasks of the upper limbs in various production settings: preliminary experience and validation].

    PubMed

    Colombini, D; Occhipinti, E

    1996-01-01

    A summary of eight investigations is presented, which were carried out using standardised methods, for the purpose of quantifying exposure to tasks involving repetitive movements of the upper limbs, as well as quantifying the prevalence of Work Related Musculo Skeletal Disorders of the upper limbs in groups of exposed workers. A total of 462 exposed workers were examined, and the study also took into account the data pertaining to a matched control group comprising 749 workers not exposed to any specific occupational risk. Regarding the quantification of exposure to increased risk, use was made of a Concise Index (OCRA), proposed by the Authors in a previous publication. The data resulting from the eight investigations were used for the study of measurements and models of association among the exposure variables (mainly represented by the OCRA index), as well as the effect variables represented by the prevalence of the various WMSDs of the upper limbs taken both individually and jointly. Significant associations were reported between the OCRA index and an effect indicator represented by the prevalence of all the WSMDs of the upper limbs, calculated on the number of upper limbs at risk. When a logarithmic conversion of the relative exposure (OCRA) and injury indices was carried out, a simple linear regression model resulted which seems to provide a satisfactory predictive performance of the risk of WMSDs of the upper limbs, based on the exposure index. The study confirmed the efficacy of various other models designed to predict effects based on multiple linear regression functions, in which the independent variables are represented by both the OCRA exposure index and by parameters relative to the breakdown by sex and age of the groups of exposed workers. PMID:9148127

  18. Occupational exposure to silica in construction workers: a literature-based exposure database.

    PubMed

    Beaudry, Charles; Lavoué, Jérôme; Sauvé, Jean-François; Bégin, Denis; Senhaji Rhazi, Mounia; Perrault, Guy; Dion, Chantal; Gérin, Michel

    2013-01-01

    We created an exposure database of respirable crystalline silica levels in the construction industry from the literature. We extracted silica and dust exposure levels in publications reporting silica exposure levels or quantitative evaluations of control effectiveness published in or after 1990. The database contains 6118 records (2858 of respirable crystalline silica) extracted from 115 sources, summarizing 11,845 measurements. Four hundred and eighty-eight records represent summarized exposure levels instead of individual values. For these records, the reported summary parameters were standardized into a geometric mean and a geometric standard deviation. Each record is associated with 80 characteristics, including information on trade, task, materials, tools, sampling strategy, analytical methods, and control measures. Although the database was constructed in French, 38 essential variables were standardized and translated into English. The data span the period 1974-2009, with 92% of the records corresponding to personal measurements. Thirteen standardized trades and 25 different standardized tasks are associated with at least five individual silica measurements. Trade-specific respirable crystalline silica geometric means vary from 0.01 (plumber) to 0.30 mg/m³ (tunnel construction skilled labor), while tasks vary from 0.01 (six categories, including sanding and electrical maintenance) to 1.59 mg/m³ (abrasive blasting). Despite limitations associated with the use of literature data, this database can be analyzed using meta-analytical and multivariate techniques and currently represents the most important source of exposure information about silica exposure in the construction industry. It is available on request to the research community. PMID:23252413

  19. Effects of chronic oral acrylamide exposure on incremental repeated acquisition (learning) task performance in Fischer 344 rats.

    PubMed

    Garey, Joan; Paule, Merle G

    2010-01-01

    Acrylamide (ACR) is a relatively potent neurotoxicant. The ingestion of carbohydrate-containing foods cooked at high temperature exposes humans to low levels of ACR virtually daily. At relatively high levels of exposure (i.e., sub-chronic through chronic levels of exposure of >or=20mg/kg body weight/day), ACR has been shown in both rats and humans to produce a variety of effects on the nervous system. The possibility that chronic dietary exposure to ACR might produce brain toxicity which could impede the development of learning skills is a question of current concern. This research evaluated the effects of ACR on learning task performance in Fischer 344 rats exposed daily beginning prenatally and continuing throughout the lifespan. Dams were gavaged with ACR since implantation [gestation day (GD) 6] with 0, 0.1, 0.3, 1.0 or 5.0mg/kg/day through parturition. Gavaging continued at the same doses to pups through weaning on post-natal day (PND) 22 after which dosing continued via their drinking water. One male and one female per litter (8-9 per treatment group) were tested. Using an incremental repeated acquisition (IRA) task to assess learning ability, ACR-exposed Fischer 344 rats exhibited altered performance by 4 months of age. From approximately 1-8 months of age (through approximately PND 240), over 52 testing sessions, a significant treatment effect was found on percent task completed (PTC), with Tukey's post-hoc test (P<0.05) indicating a significantly lower PTC for the 5.0mg/kg/day group compared to controls. While there was no treatment effect on accuracy (P=0.53), a significant decrease in response rate was seen at 5.0mg/kg/day, suggesting that the noted decrease in PTC was due to a decrease in rate of responding, not to an effect on accuracy of task solution. Previous findings in these same animals performing a progressive ratio task for the assessment of motivation, as well as a range of tests of motoric function, suggest that this decreased response rate could be due to subtle motoric effects, or possibly due to decreases in psychomotor speed, but is most likely due to motivational effects. PMID:19846048

  20. Decoding task-based attentional modulation during face categorization

    PubMed Central

    Chiu, Yu-Chin; Esterman, Michael; Han, Yuefeng; Rosen, Heather; Yantis, Steven

    2011-01-01

    Attention is a neurocognitive mechanism that selects task-relevant sensory or mnemonic information to achieve current behavioral goals. Attentional modulation of cortical activity has been observed when attention is directed to specific locations, features, or objects. However, little is known about how high-level categorization task-set modulates perceptual representations. In the current study, observers categorized faces by gender (male vs. female) or race (Asian vs. Caucasian). Each face was perceptually ambiguous in both dimensions, such that categorization of one dimension demanded selective attention to task-relevant information within the face. We used multivoxel pattern classification (MVPC) to show that task-specific modulations evoke reliably distinct spatial patterns of activity within three face-selective cortical regions (right fusiform face area and bilateral occipital face areas). This result suggests that patterns of activity in these regions reflect not only stimulus-specific (i.e., faces vs. houses) responses, but also task-specific (i.e., race vs. gender) attentional modulation. Furthermore, exploratory whole brain MVPC (using a searchlight procedure) revealed a network of dorsal frontoparietal regions (left middle frontal gyrus, left inferior and superior parietal lobule) that also exhibit distinct patterns for the two task-sets, suggesting that these regions may represent abstract goals during high-level categorization tasks. PMID:20429856

  1. A task-based quality control metric for digital mammography

    NASA Astrophysics Data System (ADS)

    Maki Bloomquist, A. K.; Mainprize, J. G.; Mawdsley, G. E.; Yaffe, M. J.

    2014-11-01

    A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum, modulation transfer function and test-object contrast. These are then used in a non-prewhitening observer model, incorporating an eye-filter and internal noise, to predict dʹ. The model was tuned by measuring dʹ of discs in a four-alternative forced choice reader study. For each disc diameter, dʹ was used to estimate the threshold thicknesses for detectability. Data were obtained for six types of digital mammography systems using varying detector technologies and x-ray spectra. A strong correlation was found between measured and modeled values of dʹ, with Pearson correlation coefficient of 0.96. Repeated measurements from separate images of the test phantom show an average coefficient of variation in dʹ for different systems between 0.07 and 0.10. Standard deviations in the threshold thickness ranged between 0.001 and 0.017 mm. The model is robust and the results are relatively system independent, suggesting that observer model dʹ shows promise as a cross platform QC metric for digital mammography.

  2. A task-based quality control metric for digital mammography.

    PubMed

    Bloomquist, A K Maki; Mainprize, J G; Mawdsley, G E; Yaffe, M J

    2014-11-01

    A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum,modulation transfer function and test-object contrast. These are then used ina non-prewhitening observer model, incorporating an eye-filter and internal noise, to predict dʹ. The model was tuned by measuring dʹ of discs in a four-alternative forced choice reader study. For each disc diameter, dʹ was used to estimate the threshold thicknesses for detectability. Data were obtained for six types of digital mammography systems using varying detector technologies and x-ray spectra. A strong correlation was found between measured and modeled values of dʹ, with Pearson correlation coefficient of 0.96. Repeated measurements from separate images of the test phantom show an average coefficient of variation in dʹ for different systems between 0.07 and 0.10. Standard deviations in the threshold thickness ranged between 0.001 and 0.017 mm. The model is robust and the results are relatively system independent, suggesting that observer model dʹ shows promise as a cross platform QC metric for digital mammography. PMID:25325670

  3. Objective Motion Cueing Criteria Investigation Based on Three Flight Tasks

    NASA Technical Reports Server (NTRS)

    Zaal, Petrus M. T.; Schroeder, Jeffery A.; Chung, William W.

    2015-01-01

    This paper intends to help establish fidelity criteria to accompany the simulator motion system diagnostic test specified by the International Civil Aviation Organization. Twelve air- line transport pilots flew three tasks in the NASA Vertical Motion Simulator under four different motion conditions. The experiment used three different hexapod motion configurations, each with a different tradeoff between motion filter gain and break frequency, and one large motion configuration that utilized as much of the simulator's motion space as possible. The motion condition significantly affected: 1) pilot motion fidelity ratings, and sink rate and lateral deviation at touchdown for the approach and landing task, 2) pilot motion fidelity ratings, roll deviations, maximum pitch rate, and number of stick shaker activations in the stall task, and 3) heading deviation after an engine failure in the takeoff task. Significant differences in pilot-vehicle performance were used to define initial objective motion cueing criteria boundaries. These initial fidelity boundaries show promise but need refinement.

  4. Bandit-Based Task Assignment for Heterogeneous Crowdsourcing.

    PubMed

    Zhang, Hao; Ma, Yao; Sugiyama, Masashi

    2015-11-01

    We consider a task assignment problem in crowdsourcing, which is aimed at collecting as many reliable labels as possible within a limited budget. A challenge in this scenario is how to cope with the diversity of tasks and the task-dependent reliability of workers; for example, a worker may be good at recognizing the names of sports teams but not be familiar with cosmetics brands. We refer to this practical setting as heterogeneous crowdsourcing. In this letter, we propose a contextual bandit formulation for task assignment in heterogeneous crowdsourcing that is able to deal with the exploration-exploitation trade-off in worker selection. We also theoretically investigate the regret bounds for the proposed method and demonstrate its practical usefulness experimentally. PMID:26378878

  5. Prenatal exposure to nicotine impairs performance of the 5-choice serial reaction time task in adult rats.

    PubMed

    Schneider, Tomasz; Ilott, Nicholas; Brolese, Giovana; Bizarro, Lisiane; Asherson, Philip J E; Stolerman, Ian P

    2011-04-01

    Cigarette smoking is associated with a wide variety of adverse reproductive outcomes, including increased infant mortality and decreased birth weight. Prenatal exposure to tobacco smoke, of which nicotine is a major teratogenic component, has also been linked to the acceleration of the risk for different psychiatric disorders, including conduct disorder and attention deficit hyperactivity disorder (ADHD). Whether this increased risk is influenced by the direct effects of gestational nicotine exposure on the developing fetus remains uncertain. In this study we provide experimental evidence for the effects of prenatal nicotine exposure on measures of attention and impulsivity in adult male rats. Offspring of females exposed during pregnancy to 0.06 mg/ml nicotine solution as the only source of water (daily consumption: 69.6±1.4 ml/kg; nicotine blood level: 96.0±31.9 ng/ml) had lower birth weight and delayed sensorimotor development measured by negative geotaxis, righting reflex, and grip strength. In the 5-choice serial reaction time test, adult rats showed increased numbers of anticipatory responses and omissions errors, more variable response times, and lower accuracy with evidence of delayed learning of the task demands when the 1 s stimulus duration was introduced. In contrast, prenatal nicotine exposure had no effect on exploratory locomotion or delay-discounting test. Prenatal nicotine exposure increased expression of the D5 dopamine receptor gene in the striatum, but did not change expression of other dopamine-related genes (DRD4, DAT1, NR4A2, and TH) in either the striatum or the prefrontal cortex. These data suggest a direct effect of prenatal nicotine exposure on important aspects of attention, inhibitory control, or learning later in life. PMID:21289608

  6. Prenatal Exposure to Nicotine Impairs Performance of the 5-Choice Serial Reaction Time Task in Adult Rats

    PubMed Central

    Schneider, Tomasz; Ilott, Nicholas; Brolese, Giovana; Bizarro, Lisiane; Asherson, Philip J E; Stolerman, Ian P

    2011-01-01

    Cigarette smoking is associated with a wide variety of adverse reproductive outcomes, including increased infant mortality and decreased birth weight. Prenatal exposure to tobacco smoke, of which nicotine is a major teratogenic component, has also been linked to the acceleration of the risk for different psychiatric disorders, including conduct disorder and attention deficit hyperactivity disorder (ADHD). Whether this increased risk is influenced by the direct effects of gestational nicotine exposure on the developing fetus remains uncertain. In this study we provide experimental evidence for the effects of prenatal nicotine exposure on measures of attention and impulsivity in adult male rats. Offspring of females exposed during pregnancy to 0.06?mg/ml nicotine solution as the only source of water (daily consumption: 69.61.4?ml/kg; nicotine blood level: 96.031.9?ng/ml) had lower birth weight and delayed sensorimotor development measured by negative geotaxis, righting reflex, and grip strength. In the 5-choice serial reaction time test, adult rats showed increased numbers of anticipatory responses and omissions errors, more variable response times, and lower accuracy with evidence of delayed learning of the task demands when the 1?s stimulus duration was introduced. In contrast, prenatal nicotine exposure had no effect on exploratory locomotion or delay-discounting test. Prenatal nicotine exposure increased expression of the D5 dopamine receptor gene in the striatum, but did not change expression of other dopamine-related genes (DRD4, DAT1, NR4A2, and TH) in either the striatum or the prefrontal cortex. These data suggest a direct effect of prenatal nicotine exposure on important aspects of attention, inhibitory control, or learning later in life. PMID:21289608

  7. Horticulture III, IV, and V. Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the horticulture program. Section 1 contains a validated task inventory for horticulture III, IV, and V. For each task, applicable information pertaining to performance and enabling objectives,…

  8. Legal Office Procedures: Task Analyses. Competency-Based Education. Review Draft.

    ERIC Educational Resources Information Center

    Virginia Polytechnic Inst. and State Univ., Blacksburg.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in a course on legal office procedures. Section 1 contains a validated task inventory for legal office procedures. For each task, applicable information pertaining to performance and enabling objectives,…

  9. A Task-Based Language Teaching Approach to the Police Traffic Stop

    ERIC Educational Resources Information Center

    O'Connell, Stephen P.

    2014-01-01

    One possible hurdle to implementing the Task-Based Language Teaching (TBLT) approach is uncertainty about how to turn target tasks into materials that can be used in the classroom. This article discusses the steps taken to create materials for one target task (communicating with a police officer during a traffic stop) in a manner that provides a…

  10. Agricultural Production: Task Analysis for Livestock Production. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the agricultural production program. Section 1 contains a validated task inventory for the livestock production portion of agricultural production IV and V. Tasks are divided into six duty areas:…

  11. The Effects of Input-Based Tasks on the Development of Learners' Pragmatic Proficiency

    ERIC Educational Resources Information Center

    Takimoto, Masahiro

    2009-01-01

    The present study evaluates the relative effectiveness of three types of input-based approaches for teaching English polite request forms to sixty Japanese learners of English: (a) structured input tasks with explicit information; (b) problem-solving tasks; and (c) structured input tasks without explicit information. Treatment group performance…

  12. Task- and Time-Dependent Weighting Factors in a Retrospective Exposure Assessment of Chemical Laboratory Workers

    SciTech Connect

    Scott A. Henn, David F. Utterback, Kathleen M. Waters, Andrea M. Markey, William G. Tankersley

    2007-02-01

    Results are reported from a chemical exposure assessment that was conducted for a cohort mortality study of 6157 chemical laboratory workers employed between 1943 and 1998 at four Department of Energy sites in Oak Ridge, Tenn., and Aiken, S.C.

  13. Regular Exercise Enhances Task-Based Industriousness in Laboratory Rats

    PubMed Central

    Laurence, Nicholas C.; Labuschagne, Lisa G.; Lura, Brent G.; Hillman, Kristin L.

    2015-01-01

    Individuals vary greatly in their willingness to select and persist in effortful tasks, even when high-effort will knowingly result in high-reward. Individuals who select and successively complete effortful, goal-directed tasks can be described as industrious. Trying to increase one’s industriousness is desirable from a productivity standpoint, yet intrinsically challenging given that effort expenditure is generally aversive. Here we show that in laboratory rats, a basic physical exercise regimen (20 min/day, five days/week) is sufficient to increase industriousness across a battery of subsequent testing tasks. Exercised rats outperformed their non-exercised counterparts in tasks designed to tax effort expenditure, strategic decision-making, problem solving and persistence. These increases in performance led to quicker reward obtainment and greater reward gain over time, and could not be accounted for simply by increased locomotor activity. Our results suggest that a basic exercise regimen can enhance effortful goal-directed behaviour in goal-directed tasks, which highlights a potential productivity benefit of staying physically active. PMID:26083255

  14. Personal exposure assessment to particulate metals using a paper-based analytical device

    NASA Astrophysics Data System (ADS)

    Cate, David; Volckens, John; Henry, Charles

    2013-03-01

    The development of a paper-based analytical device (PAD) for assessing personal exposure to particulate metals will be presented. Human exposure to metal aerosols, such as those that occur in the mining, construction, and manufacturing industries, has a significant impact on the health of our workforce, costing an estimated $10B in the U.S and causing approximately 425,000 premature deaths world-wide each year. Occupational exposure to particulate metals affects millions of individuals in manufacturing, construction (welding, cutting, blasting), and transportation (combustion, utility maintenance, and repair services) industries. Despite these effects, individual workers are rarely assessed for their exposure to particulate metals, due mainly to the high cost and effort associated with personal exposure measurement. Current exposure assessment methods for particulate metals call for an 8-hour filter sample, after which time, the filter sample is transported to a laboratory and analyzed by inductively-coupled plasma (ICP). The time from sample collection to reporting is typically weeks and costs several hundred dollars per sample. To exacerbate the issue, method detection limits suffer because of sample dilution during digestion. The lack of sensitivity hampers task-based exposure assessment, for which sampling times may be tens of minutes. To address these problems, and as a first step towards using microfluidics for personal exposure assessment, we have developed PADs for measurement of Pb, Cd, Cr, Fe, Ni, and Cu in aerosolized particulate matter.

  15. Organizational factors and mental health in community volunteers. The role of exposure, preparation, training, tasks assigned, and support.

    PubMed

    Thormar, Sigridur Bjork; Gersons, Berthold P R; Juen, Barbara; Djakababa, Maria Nelden; Karlsson, Thorlakur; Olff, Miranda

    2013-01-01

    During disasters, aid organizations often respond using the resources of local volunteer members from the affected population who are not only inexperienced, but who additionally take on some of the more psychologically and physically difficult tasks in order to provide support for their community. Although not much empirical evidence exists to justify the claim, it is thought that preparation, training, and organizational support limit (or reduce) a volunteer's risk of developing later psychopathology. In this study, we examined the effects of preparation, training, and organizational support and assigned tasks on the mental health of 506 Indonesian Red Cross volunteers who participated in the response to a massive earthquake in Yogyakarta, Indonesia, in 2006. Controlling for exposure level, the volunteers were assessed for post-traumatic stress disorder (PTSD), anxiety, depression, and subjective health complaints (SHCs) 6, 12, and 18 months post-disaster. Results showed high levels of PTSD and SHCs up to 18 months post-disaster, while anxiety and depression levels remained in the normal range. Higher levels of exposure as well as certain tasks (e.g., provision of psychosocial support to beneficiaries, handling administration, or handing out food aid) made the volunteers more vulnerable. Sense of safety, expressed general need for support at 6 months, and a lack of perceived support from team leaders and the organization were also related to greater psychopathology at 18 months. The results highlight the importance of studying organizational factors. By incorporating these results into future volunteer management programs the negative effects of disaster work on volunteers can be ameliorated. PMID:23205850

  16. Task-Based Cohesive Evolution of Dynamic Brain Networks

    NASA Astrophysics Data System (ADS)

    Davison, Elizabeth

    2014-03-01

    Applications of graph theory to neuroscience have resulted in significant progress towards a mechanistic understanding of the brain. Functional network representation of the brain has linked efficient network structure to psychometric intelligence and altered configurations with disease. Dynamic graphs provide us with tools to further study integral properties of the brain; specifically, the mathematical convention of hyperedges has allowed us to study the brain's cross-linked structure. Hyperedges capture the changes in network structure by identifying groups of brain regions with correlation patterns that change cohesively through time. We performed a hyperedge analysis on functional MRI data from 86 subjects and explored the cohesive evolution properties of their functional brain networks as they performed a series of tasks. Our results establish the hypergraph as a useful measure in understanding functional brain dynamics over tasks and reveal characteristic differences in the co-evolution structure of task-specific networks.

  17. Opportunity-to-Learn Context-Based Tasks Provided by Mathematics Textbooks

    ERIC Educational Resources Information Center

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-01-01

    Based on the findings of an error analysis revealing that Indonesian ninth- and tenth-graders had difficulties in solving context-based tasks, we investigated the opportunity-to-learn offered by Indonesian textbooks for solving context-based mathematics tasks and the relation of this opportunity-to-learn to students' difficulties in solving these…

  18. SKE/BKE task-based methodology for calculating Hotelling observer SNR in mammography

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Kyprianou, Iacovos S.; Badano, Aldo; Myers, Kyle J.; Jennings, Robert J.; Park, Subok; Kaczmarek, Richard V.; Chakrabarti, Kish

    2009-02-01

    A common method for evaluating projection mammography is Contrast-Detail (CD) curves derived from the CD phantom for Mammography (CDMAM). The CD curves are derived either by human observers, or by automated readings. Both methods have drawbacks which limit their reliability. The human based reading is significantly affected by reader variability, reduced precision and bias. On the other hand, the automated methods suffer from limited statistics. The purpose of this paper is to develop a simple and reliable methodology for the evaluation of mammographic imaging systems using the Signal Known Exactly/Background Known Exactly (SKE/BKE) detection task for signals relevant to mammography. In this paper, we used the spatial definition of the ideal, linear (Hotelling) observer to calculate the task-specific SNR for mammography and discussed the results. The noise covariance matrix as well as the detector response H matrix of the imaging system were estimated and used to calculate the SNRSKEBKE for the simulated discs of the CDMAM. The SNR as a function of exposure, disc diameter and thickness were calculated.

  19. Trayectorias: A New Model for Online Task-Based Learning

    ERIC Educational Resources Information Center

    Ros i Sole, Cristina; Mardomingo, Raquel

    2004-01-01

    This paper discusses a framework for designing online tasks that capitalizes on the possibilities that the Internet and the Web offer for language learning. To present such a framework, we draw from constructivist theories (Brooks and Brooks, 1993) and their application to educational technology (Newby, Stepich, Lehman and Russell, 1996; Jonassen,…

  20. Enhancing Automaticity through Task-Based Language Learning

    ERIC Educational Resources Information Center

    De Ridder, Isabelle; Vangehuchten, Lieve; Gomez, Marta Sesena

    2007-01-01

    In general terms automaticity could be defined as the subconscious condition wherein "we perform a complex series of tasks very quickly and efficiently, without having to think about the various components and subcomponents of action involved" (DeKeyser 2001: 125). For language learning, Segalowitz (2003) characterised automaticity as a more…

  1. Design and Analysis in Task-Based Language Assessment.

    ERIC Educational Resources Information Center

    Mislevy, Robert J.; Steinberg, Linda S.; Almond, Russell G.

    2002-01-01

    Introduces a framework for systematizing the design of language performance assessments and explicating the role of tasks within them. Their design outlines fundamental components that must be rationalized and operationalized in order for performance assessment to produce coherent evidence of examinees' abilities. (Author/VWL)

  2. Task Templates Based on Misconception Research. CSE Report 646.

    ERIC Educational Resources Information Center

    Cromley, Jennifer G.; Mislevy, Robert J.

    2004-01-01

    Researchers spend much time and effort developing measures, including measures of students? conceptual knowledge. In an effort to make such assessments easier to design, the Principled Assessment Designs for Inquiry (PADI) project has developed a framework for designing tasks and to illustrate that its use has ?reverse engineered? several …

  3. Investigating the Communicative Outcomes of Task-Based Interaction.

    ERIC Educational Resources Information Center

    Yule, George; Powers, Maggie

    1994-01-01

    Studied communicative outcomes of nonnative speaker interactions and presents a methodological framework for the analysis of different solutions to referential problems encountered in a task. The framework permits identification of what types of participation arrangements might result in more or less beneficial interactions for learners. (Contains…

  4. The Effects of Study Tasks in a Computer-Based Chemistry Learning Environment

    NASA Astrophysics Data System (ADS)

    Urhahne, Detlef; Nick, Sabine; Poepping, Anna Christin; Schulz, Sarah Jayne

    2013-12-01

    The present study examines the effects of different study tasks on the acquisition of knowledge about acids and bases in a computer-based learning environment. Three different task formats were selected to create three treatment conditions: learning with gap-fill and matching tasks, learning with multiple-choice tasks, and learning only from text and figures without any additional tasks. Participants were 196 ninth-grade students who learned with a self-developed multimedia program in a pretest-posttest control group design. Research results reveal that gap-fill and matching tasks were most effective in promoting knowledge acquisition, followed by multiple-choice tasks, and no tasks at all. The findings are in line with previous research on this topic. The effects can possibly be explained by the generation-recognition model, which predicts that gap-fill and matching tasks trigger more encompassing learning processes than multiple-choice tasks. It is concluded that instructional designers should incorporate more challenging study tasks for enhancing the effectiveness of computer-based learning environments.

  5. Determination of 2-butoxyethanol emissions from selected consumer products and its application in assessment of inhalation exposure associated with cleaning tasks.

    PubMed

    Zhu, J; Cao, X L; Beauchamp, R

    2001-06-01

    Consumer products are important sources of human exposure to certain chemicals. Recent regulatory requirements for assessing human exposure to three glycol ethers, namely 2-methoxyethanol (ME), 2-ethoxyethanol (EE) and 2-butoxyethanol (BE), have prompted the investigation of these chemicals in consumer products and their emission characteristics. Thirteen products were selected for investigation based on their potential of containing the chemicals. Headspace results indicated that ME and EE were not present in any of the 13 selected products, while BE was detected in the headspace samples of seven products, of which five were household cleaning agents. Other related compounds such as 2-hexyloxyethanol (HE) and 2-(2-butoxyethoxy)ethanol (BEE) were also detected in the headspace samples of some products. BE emissions from five cleaning related products were measured using a field and laboratory emission cell (FLEC) with its subunit to provide emission data for inhalation exposure assessment purposes. These products had initial emission factors ranging from 145 to 938 mg m(-2) h(-1) under the experimental conditions. It was found that the emission factor of BE was inversely proportional to the dilution factor of the products. A good relationship was established between the emission factor of BE and its concentrations in water-based products. Based on product use scenarios developed by US EPA and an assumed "standard room," average daily inhalation exposure levels of a resident as a result of performing cleaning tasks were estimated to be 0.075 and 0.186 mg (kg b.w.)(-1) day(-1) for two all-purpose spray cleaners, and 0.004 and 0.006 mg (kg b.w.)(-1) day(-1) for two-spray glass cleaners, respectively. PMID:11485228

  6. The evaluation and quantification of respirable coal and silica dust concentrations: a task-based approach.

    PubMed

    Grové, T; Van Dyk, T; Franken, A; Du Plessis, J

    2014-01-01

    Silicosis and coal worker's pneumoconiosis are serious occupational respiratory diseases associated with the coal mining industry and the inhalation of respirable dusts containing crystalline silica. The purpose of this study (funded by the Mine Health and Safety Council of South Africa) was to evaluate the individual contributions of underground coal mining tasks to the respirable dust and respirable silica dust concentrations in an underground section by sampling the respirable dust concentrations at the intake and return of each task. The identified tasks were continuous miner (CM) cutting, construction, transfer of coal, tipping, and roof bolting. The respirable dust-generating hierarchy of the tasks from highest to lowest was: transfer of coal > CM right cutting > CM left cutting > CM face cutting > construction > roof bolting > tipping; and for respirable silica dust: CM left cutting > construction > transfer of coal > CM right cutting. Personal exposure levels were determined by sampling the exposures of workers performing tasks in the section. Respirable dust concentrations and low concentrations of respirable silica dust were found at the intake air side of the section, indicating that air entering the section is already contaminated. The hierarchy for personal respirable dust exposures was as follows, from highest to lowest: CM operator > cable handler > miner > roof bolt operator > shuttle car operator, and for respirable silica dust: shuttle car operator > CM operator > cable handler > roof bolt operator > miner. Dust control methods to lower exposures should include revision of the position of workers with regard to the task performed, positioning of the tasks with regard to the CM cutting, and proper use of the line curtains to direct ventilation appropriately. The correct use of respiratory protection should also be encouraged. PMID:24380473

  7. Performance-based workload assessment: Allocation strategy and added task sensitivity

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1990-01-01

    The preliminary results of a research program investigating the use of added tasks to evaluate mental workload are reviewed. The focus of the first studies was a reappraisal of the traditional secondary task logic that encouraged the use of low-priority instructions for the added task. It was believed that such low-priority tasks would encourage subjects to split their available resources among the two tasks. The primary task would be assigned all the resources it needed, and any remaining reserve capacity would be assigned to the secondary task. If the model were correct, this approach was expected to combine sensitivity to primary task difficulty with unintrusiveness to primary task performance. The first studies of the current project demonstrated that a high-priority added task, although intrusive, could be more sensitive than the traditional low-priority secondary task. These results suggested that a more appropriate model of the attentional effects associated with added task performance might be based on capacity switching, rather than the traditional optimal allocation model.

  8. Boys, not girls, are negatively affected on cognitive tasks by lead exposure: a pilot study.

    PubMed

    Khanna, Maya M

    2015-01-01

    The study described in this article provides behavioral evidence that boys experience the deleterious cognitive effects of lead more than girls do. In fact, girls with elevated blood lead levels (BLLs - 10 μg/dL) performed as well as girls without elevated BLLs on behavioral measures of cognition. This was shown by testing executive function and reading readiness skills of 40 young children (aged three to six years; 23 with elevated blood lead levels, 17 without) residing within a U.S. Environmental Protection Agency-designated lead Superfund site. The results also indicate that elevated BLLs are related to a more pronounced negative impact on executive function than on reading readiness. These findings support recent research on adults indicating that lead exposure is related to atrophy within the prefrontal cortex and other work suggesting that estrogen and estradiol may act as neuroprotectants against the negative impact of neurotoxins. PMID:25619039

  9. The measurement and facilitation of cooperative task performance. [reactions of humans to stress exposure

    NASA Technical Reports Server (NTRS)

    Hutchinson, R. R.

    1975-01-01

    Experiments were conducted to determine under what conditions jaw clenching will occur in humans as a response to stress exposure. The method for measuring reactions to stress involves a series of electrical recordings of the masseter and temporalis muscles. A high fixed-ratio response requirement in the first series of experiments shows that jaw clenching in humans occurs in situations analogous to those which produce biting in infrahuman subjects. In the second series, reduction in the amounts of money recieved by subjects is shown to cause increases in the jaw clench response and other negative effect motor behaviors. The third series demonstrates that perception of more favorable conditions existing for another person can increase anger and hostility in the subject.

  10. Task discrimination from myoelectric activity: a learning scheme for EMG-based interfaces.

    PubMed

    Liarokapis, Minas V; Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J

    2013-06-01

    A learning scheme based on Random Forests is used to discriminate the task to be executed using only myoelectric activity from the upper limb. Three different task features can be discriminated: subspace to move towards, object to be grasped and task to be executed (with the object). The discrimination between the different reach to grasp movements is accomplished with a random forests classifier, which is able to perform efficient features selection, helping us to reduce the number of EMG channels required for task discrimination. The proposed scheme can take advantage of both a classifier and a regressor that cooperate advantageously to split the task space, providing better estimation accuracy with task-specific EMG-based motion decoding models, as reported in [1] and [2]. The whole learning scheme can be used by a series of EMG-based interfaces, that can be found in rehabilitation cases and neural prostheses. PMID:24187185

  11. Perceptions of Task-Based Language Teaching: A Study of Iranian EFL Learners

    ERIC Educational Resources Information Center

    Hadi, Atefeh

    2013-01-01

    This paper explored perceptions of Task-Based Language Teaching (TBLT) among a group of Iranian female learners. A sample of 88 English as a Foreign Language (EFL) learners participated in the study. A task-based questionnaire was developed to examine the perceptions of the participants. The results suggested a high level of understanding of TBLT…

  12. Learner Use of Holistic Language Units in Multimodal, Task-Based Synchronous Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Collentine, Karina

    2009-01-01

    Second language acquisition (SLA) researchers strive to understand the language and exchanges that learners generate in synchronous computer-mediated communication (SCMC). Doughty and Long (2003) advocate replacing open-ended SCMC with task-based language teaching (TBLT) design principles. Since most task-based SCMC (TB-SCMC) research addresses an…

  13. An EEG-based mental workload estimator trained on working memory task can work well under simulated multi-attribute task

    PubMed Central

    Ke, Yufeng; Qi, Hongzhi; He, Feng; Liu, Shuang; Zhao, Xin; Zhou, Peng; Zhang, Lixin; Ming, Dong

    2014-01-01

    Mental workload (MW)-based adaptive system has been found to be an effective approach to enhance the performance of human-machine interaction and to avoid human error caused by overload. However, MW estimated from the spontaneously generated electroencephalogram (EEG) was found to be task-specific. In existing studies, EEG-based MW classifier can work well under the task used to train the classifier (within-task) but crash completely when used to classify MW of a task that is similar to but not included in the training data (cross-task). The possible causes have been considered to be the task-specific EEG patterns, the mismatched workload across tasks and the temporal effects. In this study, cross-task performance-based feature selection (FS) and regression model were tried to cope with these challenges, in order to make EEG-based MW estimator trained on working memory tasks work well under a complex simulated multi-attribute task (MAT). The results show that the performance of regression model trained on working memory task and tested on multi-attribute task with the feature subset picked-out were significantly improved (correlation coefficient (COR): 0.740 ± 0.147 and 0.598 ± 0.161 for FS data and validation data respectively) when compared to the performance in the same condition with all features (chance level). It can be inferred that there do exist some MW-related EEG features can be picked out and there are something in common between MW of a relatively simple task and a complex task. This study provides a promising approach to measure MW across tasks. PMID:25249967

  14. Human exposure to carbon-based fibrous nanomaterials: A review.

    PubMed

    Guseva Canu, Irina; Bateson, Thomas F; Bouvard, Veronique; Debia, Maximilien; Dion, Chantal; Savolainen, Kai; Yu, Il-Je

    2016-03-01

    In an emerging field of nanotechnologies, assessment of exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF) is an integral component of occupational and environmental epidemiology, risk assessment and management, as well as regulatory actions. The current state of knowledge on exposure to carbon-based fibrous nanomaterials among workers, consumers and general population was studied in frame of the International Agency for Research on Cancer (IARC) Monographs-Volume 111 "Some Nanomaterials and Some Fibres". Completeness and reliability of available exposure data for use in epidemiology and risk assessment were assessed. Occupational exposure to CNT/CNF may be of concern at all stages of the material life-cycle from research through manufacture to use and disposal. Consumer and environmental exposures are only estimated by modeled data. The available information of the final steps of the life-cycle of these materials remains incomplete so far regarding amounts of handled materials and levels of exposure. The quality and amount of information available on the uses and applications of CNT/CNF should be improved to enable quantitative assessment of human exposure to these materials. For that, coordinated effort in producing surveys and exposure inventories based on harmonized strategy of material test, exposure measurement and reporting results is strongly encouraged. PMID:26752069

  15. Exposure-Based Cat Modeling, Available data, Advantages, & Limitations

    NASA Astrophysics Data System (ADS)

    Michel, Gero; Hosoe, Taro; Schrah, Mike; Saito, Keiko

    2010-05-01

    This paper discusses the advantages and disadvantages of exposure data for cat-modeling and considers concepts of scale as well as the completeness of data and data scoring using field/model examples. Catastrophe modeling based on exposure data has been considered the panacea for insurance-related cat modeling since the late 1980's. Reasons for this include: • The ability to extend risk modeling to consider data beyond historical losses, • Usability across many relevant scales, • Flexibility in addressing complex structures and policy conditions, and • Ability to assess dependence of risk results on exposure-attributes and exposure-modifiers, such as lines of business, occupancy types, and mitigation features, at any given scale. In order to calculate related risk, monetary exposure is correlated to vulnerabilities that have been calibrated with historical results, plausibility concepts, and/or physical modeling. While exposure based modeling is widely adopted, we also need to be aware of its limitations which include: • Boundaries in our understanding of the distribution of exposure, • Spatial interdependence of exposure patterns and the time-dependence of exposure, • Incomplete availability of loss information to calibrate relevant exposure attributes/structure with related vulnerabilities and losses, • The scale-dependence of vulnerability, • Potential for missing or incomplete communication of assumptions made during model calibration, • Inefficiencies in the aggregation or disaggregation of vulnerabilities, and • Factors which can influence losses other than exposure, vulnerability, and hazard. Although we might assume that the higher the resolution the better, regional model calibration is often limited to lower than street level resolution with higher resolution being achieved by disaggregating results using topographic/roughness features with often loosely constrained and/or varying effects on losses. This suggests that higher accuracy might actually be achieved at resolutions lower than the maximum available in current exposure cat models and as yet undefined. Further, dominance of a few models, associated consensus results, and preeminence of exposure concepts can lead to the subjective interpretation of inaccuracies in exposure distribution/attribution that can result in biased model results. More extreme solutions have resulted in input exposure data being calibrated with model results in order to achieve pre-determined and self-fulfilling outcomes. These outcomes could be avoided by allowing realistic uncertainty ranges rather than restricting interpretation of risk results to misleading "consensus nutshell" numbers. The paper concludes by considering new concepts in the use of exposure models and describes potential scenarios for the future use of input data in cat models.

  16. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential.

    PubMed

    Mitchell, Jade; Arnot, Jon A; Jolliet, Olivier; Georgopoulos, Panos G; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A; Vallero, Daniel A

    2013-08-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA's need to develop novel approaches and tools for rapidly prioritizing chemicals, a "Challenge" was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA's effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  17. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

    PubMed Central

    Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

    2014-01-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  18. Task-driven equipment inspection system based on safe workflow model

    NASA Astrophysics Data System (ADS)

    Guo, Xinyou; Liu, Yangguang

    2010-12-01

    An equipment inspection system is one that contains a number of equipment queues served in cyclic order. In order to satisfy multi-task scheduling and multi-task combination requirements for equipment inspection system, we propose a model based on inspection workflow in this paper. On the one hand, the model organizes all kinds of equipments according to inspection workflow, elemental work units according to inspection tasks, combination elements according to the task defined by users. We proposed a 3-dimensional workflow model for equipments inspection system including organization sub-model, process sub-model and data sub-model. On the other hand, the model is based on the security authorization which defined by relation between roles, tasks, pre-defined business workflows and inspection data. The system based on proposed framework is safe and efficient. Our implement shows that the system is easy to operate and manage according to the basic performance.

  19. A novel task assessing intention and emotion attribution: Italian standardization and normative data of the Story-based Empathy Task.

    PubMed

    Dodich, Alessandra; Cerami, Chiara; Canessa, Nicola; Crespi, Chiara; Iannaccone, Sandro; Marcone, Alessandra; Realmuto, Sabrina; Lettieri, Giada; Perani, Daniela; Cappa, Stefano F

    2015-10-01

    Theory of Mind (ToM), the process by which an individual imputes mental states to himself and others, is presently considered as a multidimensional cognitive domain, with two main facets (i.e., cognitive and affective ToM) accounting, respectively, for the ability to understand others' intention (intention attribution-IA) and emotions (emotion attribution-EA). Despite the large amount of literature investigating the behavioural and neural bases of mentalizing abilities in neurological conditions, there is still a lack of validated neuropsychological tools specifically designed to assess such skills. Here, we report the normative data of the Story-Based Empathy Task (SET), a non-verbal test developed for the assessment of intention and emotion attribution in the neurodegenerative conditions characterized by the impairment of social-emotional abilities. It is an easy-to-administer task including 18 stimuli, sub-grouped into two experimental conditions assessing, respectively, the ability to infer others' intentions (SET-IA) and emotions (SET-EA), compared to a control condition of causal inference (SET-CI). Normative data were collected in 136 Italian subjects pooled across subgroups homogenous for age (range 20-79 years), sex, and education (at least 5 years). The results show a detrimental effect of age and a beneficial effect of education on both the global score and each subscale, for which we provide correction grids. This new task could be a useful tool to investigate both affective and cognitive aspects of ToM in the course of disorders of socio-emotional behaviour, such as the fronto-temporal dementia spectrum. PMID:26072203

  20. Students' Geometrical Perception on a Task-Based Dynamic Geometry Platform

    ERIC Educational Resources Information Center

    Leung, Allen; Lee, Arthur Man Sang

    2013-01-01

    This paper describes a task-based dynamic geometry platform that is able to record student responses in a collective fashion to pre-designed dragging tasks. The platform provides a new type of data and opens up a quantitative dimension to interpret students' geometrical perception in dynamic geometry environments. The platform is capable of…

  1. Measurement and Evidence of Computer-Based Task Switching and Multitasking by "Net Generation" Students

    ERIC Educational Resources Information Center

    Judd, Terry; Kennedy, Gregor

    2011-01-01

    Logs of on-campus computer and Internet usage were used to conduct a study of computer-based task switching and multitasking by undergraduate medical students. A detailed analysis of over 6000 individual sessions revealed that while a majority of students engaged in both task switching and multitasking behaviours, they did so less frequently than

  2. Frontal Lobe Involvement in a Task of Time-Based Prospective Memory

    ERIC Educational Resources Information Center

    McFarland, Craig P.; Glisky, Elizabeth L.

    2009-01-01

    Time-based prospective memory (PM) has been found to be negatively affected by aging, possibly as a result of declining frontal lobe (FL) function. Despite a clear retrospective component to PM tasks, the medial temporal lobes (MTL) are thought to play only a secondary role in successful task completion. The present study investigated the role of…

  3. Balancing Classroom Management with Mathematical Learning: Using Practice-Based Task Design in Mathematics Teacher Education

    ERIC Educational Resources Information Center

    Biza, Irene; Nardi, Elena; Joel, Gareth

    2015-01-01

    In this paper we present the results from a study in which 21 mathematics trainee teachers engage with two practice-based tasks in which classroom management interferes with mathematical learning. We investigate the trainees' considerations when they make decisions in classroom situations and how these tasks can trigger their reflections on the…

  4. Measurement and Evidence of Computer-Based Task Switching and Multitasking by "Net Generation" Students

    ERIC Educational Resources Information Center

    Judd, Terry; Kennedy, Gregor

    2011-01-01

    Logs of on-campus computer and Internet usage were used to conduct a study of computer-based task switching and multitasking by undergraduate medical students. A detailed analysis of over 6000 individual sessions revealed that while a majority of students engaged in both task switching and multitasking behaviours, they did so less frequently than…

  5. Industrial Arts Instructional Tasks/Competencies for Energy and Power. Competency-Based Education.

    ERIC Educational Resources Information Center

    George Mason Univ., Fairfax, VA.

    This instructional task/competency package is designed to help teachers and administrators in developing competency-based instructional materials for an energy and power course. Part 1 contains a description of the industrial arts program and a course description, instructional task/competency list, and content outline for energy and power. The…

  6. Emotion-Based Learning on a Simplified Card Game: The Iowa and Bangor Gambling Tasks

    ERIC Educational Resources Information Center

    Bowman, Caroline H.; Turnbull, Oliver H.

    2004-01-01

    The Iowa Gambling Task (IGT) has been widely used in the assessment of neurological patients with frontal lesions. Emphasis has been placed on the complexity of the task (i.e., four decks of varying contingency pattern) with the suggestion that the participant must use emotion-based learning to deal with a complex decision-making process. The…

  7. Cognitive Style as a Factor Affecting Task-Based Reading Comprehension Test Scores

    ERIC Educational Resources Information Center

    Salmani-Nodoushan, Mohammad Ali

    2005-01-01

    For purposes of the present study, it was hypothesized that field (in)dependence would introduce systematic variance into Iranian EFL learners' overall and task-specific performance on task-based reading comprehension tests. 1743 freshman, sophomore, junior, and senior students all majoring in English at different Iranian universities and colleges…

  8. Using Heuristic Task Analysis to Create Web-Based Instructional Design Theory

    ERIC Educational Resources Information Center

    Fiester, Herbert R.

    2010-01-01

    The first purpose of this study was to identify procedural and heuristic knowledge used when creating web-based instruction. The second purpose of this study was to develop suggestions for improving the Heuristic Task Analysis process, a technique for eliciting, analyzing, and representing expertise in cognitively complex tasks. Three expert…

  9. Students' Geometrical Perception on a Task-Based Dynamic Geometry Platform

    ERIC Educational Resources Information Center

    Leung, Allen; Lee, Arthur Man Sang

    2013-01-01

    This paper describes a task-based dynamic geometry platform that is able to record student responses in a collective fashion to pre-designed dragging tasks. The platform provides a new type of data and opens up a quantitative dimension to interpret students' geometrical perception in dynamic geometry environments. The platform is capable of

  10. Performance of visually guided tasks using simulated prosthetic vision and saliency-based cues

    NASA Astrophysics Data System (ADS)

    Parikh, N.; Itti, L.; Humayun, M.; Weiland, J.

    2013-04-01

    Objective. The objective of this paper is to evaluate the benefits provided by a saliency-based cueing algorithm to normally sighted volunteers performing mobility and search tasks using simulated prosthetic vision. Approach. Human subjects performed mobility and search tasks using simulated prosthetic vision. A saliency algorithm based on primate vision was used to detect regions of interest (ROI) in an image. Subjects were cued to look toward the directions of these ROI using visual cues superimposed on the simulated prosthetic vision. Mobility tasks required the subjects to navigate through a corridor, avoid obstacles and locate a target at the end of the course. Two search task experiments involved finding objects on a tabletop under different conditions. Subjects were required to perform tasks with and without any help from cues. Results. Head movements, time to task completion and number of errors were all significantly reduced in search tasks when subjects used the cueing algorithm. For the mobility task, head movements and number of contacts with objects were significantly reduced when subjects used cues, whereas time was significantly reduced when no cues were used. The most significant benefit from cues appears to be in search tasks and when navigating unfamiliar environments. Significance. The results from the study show that visually impaired people and retinal prosthesis implantees may benefit from computer vision algorithms that detect important objects in their environment, particularly when they are in a new environment.

  11. A task-based comparison of two reconstruction algorithms for digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Mahadevan, Ravi; Ikejimba, Lynda C.; Lin, Yuan; Samei, Ehsan; Lo, Joseph Y.

    2014-03-01

    Digital breast tomosynthesis (DBT) generates 3-D reconstructions of the breast by taking X-Ray projections at various angles around the breast. DBT improves cancer detection as it minimizes tissue overlap that is present in traditional 2-D mammography. In this work, two methods of reconstruction, filtered backprojection (FBP) and the Newton-Raphson iterative reconstruction were used to create 3-D reconstructions from phantom images acquired on a breast tomosynthesis system. The task based image analysis method was used to compare the performance of each reconstruction technique. The task simulated a 10mm lesion within the breast containing iodine concentrations between 0.0mg/ml and 8.6mg/ml. The TTF was calculated using the reconstruction of an edge phantom, and the NPS was measured with a structured breast phantom (CIRS 020) over different exposure levels. The detectability index d' was calculated to assess image quality of the reconstructed phantom images. Image quality was assessed for both conventional, single energy and dual energy subtracted reconstructions. Dose allocation between the high and low energy scans was also examined. Over the full range of dose allocations, the iterative reconstruction yielded a higher detectability index than the FBP for single energy reconstructions. For dual energy subtraction, detectability index was maximized when most of the dose was allocated to the high energy image. With that dose allocation, the performance trend for reconstruction algorithms reversed; FBP performed better than the corresponding iterative reconstruction. However, FBP performance varied very erratically with changing dose allocation. Therefore, iterative reconstruction is preferred for both imaging modalities despite underperforming dual energy FBP, as it provides stable results.

  12. Validation of a novel cognitive bias task based on difference in quantity of reinforcement for assessing environmental enrichment.

    PubMed

    Keen, Heidi A; Nelson, O Lynne; Robbins, Charles T; Evans, Marc; Shepherdson, David J; Newberry, Ruth C

    2014-05-01

    Cognitive bias tasks purport to assess affective states via responses to ambiguous stimuli. We hypothesized that a novel cognitive bias task based on positive reinforcement using quantity differences would detect changes in affect in captive grizzly bears (Ursus arctos horribilis). We trained bears (n = 8) to respond differently (nose or paw touch) to two stimuli (light or dark gray cue cards), with responses counterbalanced across bears. The two cues signaled a small or large food reward, respectively. Responses to ambiguous probe stimuli (i.e., shades of gray) intermediate to the trained stimuli were classified as either 'optimistic,' appropriate for the larger reward, or 'pessimistic,' appropriate for the smaller reward. In Experiment 1, we explored the contrast in reward size necessary to detect a change in response across probe stimuli (large reward, 3 or 6 apple slices: small reward, 1 slice). We observed a change in response across probe stimuli, with no difference in response between reward-value groups, indicating that a contrast of 3:1 apple slices was sufficient to affect responses. In Experiment 2, we investigated cognitive bias after 2.1 h of exposure to enrichment items varying in attractiveness. Results were unaffected by enrichment type or time spent interacting with enrichments, indicating that the task failed to demonstrate criterion validity for comparing mood following exposure to different enrichment items. However, greater time spent pacing prior to testing was associated with 'optimistic' judgments. The data provide some support for use of cognitive bias tasks based on quantity differences in animal welfare assessments involving captive wildlife. PMID:24045850

  13. Lunar base surface mission operations. Lunar Base Systems Study (LBSS) task 4.1

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The purpose was to perform an analysis of the surface operations associated with a human-tended lunar base. Specifically, the study defined surface elements and developed mission manifests for a selected base scenario, determined the nature of surface operations associated with this scenario, generated a preliminary crew extravehicular and intravehicular activity (EVA/IVA) time resource schedule for conducting the missions, and proposed concepts for utilizing remotely operated equipment to perform repetitious or hazardous surface tasks. The operations analysis was performed on a 6 year period of human-tended lunar base operation prior to permanent occupancy. The baseline scenario was derived from a modified version of the civil needs database (CNDB) scenario. This scenario emphasizes achievement of a limited set of science and exploration objectives while emplacing the minimum habitability elements required for a permanent base.

  14. Model-based analysis of control/display interaction in the hover task

    NASA Technical Reports Server (NTRS)

    Schmidt, David K.; Garg, Sanjay

    1987-01-01

    The effect of Control/Display interaction in the hover task is analyzed using an optimal control approach to modeling pilot control behavior. The control/display configurations considered are those previously evaluated in a flight research program. The experimental data-base is reviewed and the procedure for modeling the task and the displayed information is presented in detail. All model-based results, time-domain as well as frequency-domain, are found to correlate extremely well with the subjective pilot ratings and comments. Time-domain measures consist of root mean-square errors and control inputs, attention allocation to displayed quantities, and magnitudes of task objective function. Frequency-domain measures include bandwidth, stability margins, and pilot phase compensation. Results are also shown to agree with previous findings on task interference in multi-axis tasks.

  15. Model-based estimation and prediction of task-imposed mental workload

    NASA Technical Reports Server (NTRS)

    Madni, A. M.; Lyman, J.

    1983-01-01

    Mental workload has been an area of intensive research for better than a decade. One specific area of interest in aircrew related workload research is concerned with the development of quantitative indices of workload in aircraft piloting tasks. This paper presents a model-based approach for quantifying mental workload in operational terms. The suggested modeling framework is based on an interpreted Petri net characterization of a task in which 'places' are equated to specific task-related activities and 'transitions' are viewed as internal or external forcing events. It is shown that within this framework quantitative assessments can be made of both cumulative and instantaneous workload associated with the performance of a task and its individual component subtasks. It is suggested that insights gained from analyzing task-specific workload within this modeling paradigm can suggest plausible explanations for reconciling discrepancies between subjectively elicited workload estimates and behavioral/performance measures.

  16. Influence of Planning on Students' Language Performance in Task-Based Language Teaching

    ERIC Educational Resources Information Center

    Wang, Yingli

    2008-01-01

    Task-based language teaching (TBLT) is an important second language teaching method. Planning is one of the significant factors in the studies of TBLT. This paper will mainly discuss the influence of planning on students' language performance in TBLT.

  17. Uranium internal exposure evaluation based on urine assay data

    SciTech Connect

    Lawrence, J.N.P.

    1984-09-01

    The difficulties in assessing internal exposures to uranium from urine assay data are described. A simplified application of the ICRP-30 and ICRP Lung Model concepts to the estimation of uranium intake is presented. A discussion follows on the development of a computer code utilizing the ICRP-30-based uranium elimination model with the existing urine assay information. The calculated uranium exposures from 1949 through 1983 are discussed. 13 references, 1 table.

  18. Internalizing versus externalizing control: different ways to perform a time-based prospective memory task.

    PubMed

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S

    2014-07-01

    Time-based prospective memory (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external control can be gained, and internal control minimized, by checking clocks or by using PM reminders. We present 3 experiments that examined how individuals externalize and internalize control of time-based PM tasks. The control condition performed a lexical decision task only, whereas the PM conditions were additionally required to make a time-based PM response after 11 min. We manipulated whether participants received a reminder, and whether clock checking was discouraged. In Experiments 1 and 3, no cost was found under standard clock check conditions. In contrast, when participants were discouraged from clock checking (Experiments 2 and 3), significant costs were found, accompanied by a decrease in clock checking. PM reminders prompted participants to check the clock, and improved PM accuracy if those reminders were expected. However, there was no evidence that participants could localize the internal or external control of the PM task to after the presentation of an expected reminder (Experiment 3). We conclude that much of the need for internal control can be transferred to the external world by performing a well-practiced task such as clock checking, which reminds participants of the PM task and reduces the internal control required to maintain the intention to perform the PM task. PMID:24548325

  19. Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

    PubMed

    Pleil, J D; Smith, L B; Zelnick, S D

    2000-03-01

    JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission. PMID:10706522

  20. SIMPLIFIED PHYSICS BASED MODELSRESEARCH TOPICAL REPORT ON TASK #2

    SciTech Connect

    Mishra, Srikanta; Ganesh, Priya

    2014-10-31

    We present a simplified-physics based approach, where only the most important physical processes are modeled, to develop and validate simplified predictive models of CO2 sequestration in deep saline formation. The system of interest is a single vertical well injecting supercritical CO2 into a 2-D layered reservoir-caprock system with variable layer permeabilities. We use a set of well-designed full-physics compositional simulations to understand key processes and parameters affecting pressure propagation and buoyant plume migration. Based on these simulations, we have developed correlations for dimensionless injectivity as a function of the slope of fractional-flow curve, variance of layer permeability values, and the nature of vertical permeability arrangement. The same variables, along with a modified gravity number, can be used to develop a correlation for the total storage efficiency within the CO2 plume footprint. Similar correlations are also developed to predict the average pressure within the injection reservoir, and the pressure buildup within the caprock.

  1. Risk-based indicators of Canadians’ exposures to environmental carcinogens

    PubMed Central

    2013-01-01

    Background Tools for estimating population exposures to environmental carcinogens are required to support evidence-based policies to reduce chronic exposures and associated cancers. Our objective was to develop indicators of population exposure to selected environmental carcinogens that can be easily updated over time, and allow comparisons and prioritization between different carcinogens and exposure pathways. Methods We employed a risk assessment-based approach to produce screening-level estimates of lifetime excess cancer risk for selected substances listed as known carcinogens by the International Agency for Research on Cancer. Estimates of lifetime average daily intake were calculated using population characteristics combined with concentrations (circa 2006) in outdoor air, indoor air, dust, drinking water, and food and beverages from existing monitoring databases or comprehensive literature reviews. Intake estimates were then multiplied by cancer potency factors from Health Canada, the United States Environmental Protection Agency, and the California Office of Environmental Health Hazard Assessment to estimate lifetime excess cancer risks associated with each substance and exposure pathway. Lifetime excess cancer risks in excess of 1 per million people are identified as potential priorities for further attention. Results Based on data representing average conditions circa 2006, a total of 18 carcinogen-exposure pathways had potential lifetime excess cancer risks greater than 1 per million, based on varying data quality. Carcinogens with moderate to high data quality and lifetime excess cancer risk greater than 1 per million included benzene, 1,3-butadiene and radon in outdoor air; benzene and radon in indoor air; and arsenic and hexavalent chromium in drinking water. Important data gaps were identified for asbestos, hexavalent chromium and diesel exhaust in outdoor and indoor air, while little data were available to assess risk for substances in dust, food and beverages. Conclusions The ability to track changes in potential population exposures to environmental carcinogens over time, as well as to compare between different substances and exposure pathways, is necessary to support comprehensive, evidence-based prevention policy. We used estimates of lifetime excess cancer risk as indicators that, although based on a number of simplifying assumptions, help to identify important data gaps and prioritize more detailed data collection and exposure assessment needs. PMID:23398723

  2. Research on Multirobot Pursuit Task Allocation Algorithm Based on Emotional Cooperation Factor

    PubMed Central

    Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

    2014-01-01

    Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm. PMID:25152925

  3. Research on multirobot pursuit task allocation algorithm based on emotional cooperation factor.

    PubMed

    Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

    2014-01-01

    Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm. PMID:25152925

  4. Task-oriented multi-robot learning in behavior-based systems

    SciTech Connect

    Parker, L.E.

    1996-12-31

    A large application domain for multi-robot teams involves task- oriented missions, in which potentially heterogeneous robots must solve several distinct tasks. Previous research addressing this problem in multi-robot systems has largely focused on issues of efficiency, while ignoring the real-world situated robot needs of fault tolerance` and adaptivity. This paper addresses this problem by developing an architecture called L-ALLIANCE that incorporates task- oriented action selection mechanisms into a behavior-based system, thus increasing the efficiency of robot team performance while maintaining the desirable characteristics of fault tolerance and adaptivity. We present our investigations of several competing control strategies and derive an approach that works well in a wide variety of multi-robot task-oriented mission scenarios. We provide a formal model of this technique to illustrate how it can be incorporated into any behavior-based system.

  5. Examining the dynamic relationships between exposure tasks and cognitive restructuring in CBT for SAD: Outcomes and moderating influences.

    PubMed

    Hawley, Lance L; Rector, Neil A; Laposa, Judith M

    2016-04-01

    Meta-analyses indicate that cognitive behavioral therapy (CBT) for social anxiety disorder (SAD) leads to substantial symptom alleviation. Although there is an emphasis on engaging in exposure and cognitive restructuring during treatment, the longitudinal relationship between skill use and symptom alleviation is not well understood. Furthermore, treatment response may be attenuated by pre-existing patient vulnerabilities. This study examined the longitudinal association of skill use (i.e. exposure (EX), thought record use (TR)), symptom reduction and the potential moderating influence of perfectionism during a 12-session, manual-based CBT for SAD intervention for 100 patients (51% female) meeting DSM-IV criteria for SAD. Results obtained from Latent Difference Score (LDS) models indicated that the frequency of both EX and TR skill use led to subsequent symptom alleviation; however, this varied based on the type of skill used. Further, although both EX and TR interventions were associated with subsequent symptom reduction, the association of EX and subsequent symptom alleviation was greater than the association of TR and subsequent symptom alleviation. Finally, higher pre-treatment perfectionism was associated with greater initial skill use, followed by significantly reduced skill use in later sessions. These preliminary results suggest that perfectionistic individuals demonstrate differential engagement in EX and TR interventions during treatment. PMID:26905316

  6. Behavior-based multi-robot collaboration for autonomous construction tasks

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghazarian, Hrand; Robinson, Matthew

    2005-01-01

    The Robot Construction Crew (RCC) is a heterogeneous multi-robot system for autonomous construction of a structure through assembly of Long components. The two robot team demonstrates component placement into an existing structure in a realistic environment. The task requires component acquisition, cooperative transport, and cooperative precision manipulation. A behavior-based architecture provides adaptability. The RCC approach minimizes computation, power, communication, and sensing for applicability to space-related construction efforts, but the techniques are applicable to terrestrial construction tasks.

  7. A task-oriented modular and agent-based collaborative design mechanism for distributed product development

    NASA Astrophysics Data System (ADS)

    Liu, Jinfei; Chen, Ming; Wang, Lei; Wu, Qidi

    2014-05-01

    The rapid expansion of enterprises makes product collaborative design (PCD) a critical issue under the distributed heterogeneous environment, but as the collaborative task of large-scale network becomes more complicated, neither unified task decomposition and allocation methodology nor Agent-based network management platform can satisfy the increasing demands. In this paper, to meet requirements of PCD for distributed product development, a collaborative design mechanism based on the thought of modularity and the Agent technology is presented. First, the top-down 4-tier process model based on task-oriented modular and Agent is constructed for PCD after analyzing the mapping relationships between requirements and functions in the collaborative design. Second, on basis of sub-task decomposition for PCD based on a mixed method, the mathematic model of task-oriented modular based on multi-objective optimization is established to maximize the module cohesion degree and minimize the module coupling degree, while considering the module executable degree as a restriction. The mathematic model is optimized and simulated by the modified PSO, and the decomposed modules are obtained. Finally, the Agent structure model for collaborative design is put forward, and the optimism matching Agents are selected by using similarity algorithm to implement different task-modules by the integrated reasoning and decision-making mechanism with the behavioral model of collaborative design Agents. With the results of experimental studies for automobile collaborative design, the feasibility and efficiency of this methodology of task-oriented modular and Agent-based collaborative design in the distributed heterogeneous environment are verified. On this basis, an integrative automobile collaborative R&D platform is developed. This research provides an effective platform for automobile manufacturing enterprises to achieve PCD, and helps to promote product numeralization collaborative R&D and management development.

  8. Co-Constructional Task Analysis: Moving beyond Adult-Based Models to Assess Young Children's Task Performance

    ERIC Educational Resources Information Center

    Lee, Scott Weng Fai

    2013-01-01

    The assessment of young children's thinking competence in task performances has typically followed the novice-to-expert regimen involving models of strategies that adults use when engaged in cognitive tasks such as problem-solving and decision-making. Socio-constructivists argue for a balanced pedagogical approach between the adult and child…

  9. The preliminary Long Duration Exposure Facility (LDEF) materials data base

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1992-01-01

    A preliminary Long Duration Exposure Facility (LDEF) Materials Data Base was developed by the LDEF Materials Special Investigation Group (MSIG). The LDEF Materials Data Base is envisioned to eventually contain the wide variety and vast quantity of materials data generated for LDEF. The data is searchable by optical, thermal, and mechanical properties, exposure parameters (such as atomic oxygen flux), and author(s) or principal investigator(s). The LDEF Materials Data Base was incorporated into the Materials and Processes Technical Information System (MAPTIS). MAPTIS is a collection of materials data which was computerized and is available to engineers, designers, and researchers in the aerospace community involved in the design and development of spacecraft and related hardware. This paper describes the LDEF Materials Data Base and includes step-by-step example searches using the data base. Information on how to become an authorized user of the system is included.

  10. Exposure to childhood trauma is associated with altered n-back activation and performance in healthy adults: implications for a commonly used working memory task

    PubMed Central

    Philip, Noah S.; Sweet, Lawrence H.; Tyrka, Audrey R.; Carpenter, S. Louisa; Albright, Sarah E.; Price, Lawrence H.; Carpenter, Linda L.

    2015-01-01

    Previous research suggests that a history of early life stress (ELS) impacts working memory (WM) in adulthood. Despite the widespread use of WM paradigms, few studies have evaluated whether ELS exposure, in the absence of psychiatric illness, also impacts WM-associated brain activity in ways that might improve sensitivity to these ELS effects or provide insights into the mechanisms of these effects. This study evaluated whether ELS affects WM behavioral performance and task-associated activity by acquiring 3T functional images from 27 medication-free healthy adults (14 with ELS) during an N-back WM task that included 0- and 2-back components. Whole brain voxel-wise analysis was performed to evaluate WM activation, followed by region of interest analyses to evaluate relationships between activation and clinical variables. ELS was associated with poorer accuracy during the 2-back (79 %±19 vs. 92 %±9, p=0.049); accuracy and response time otherwise did not differ between groups. During the 0-back, ELS participants demonstrated increased activation in the superior temporal gyrus/insula, left inferior parietal lobule (IPL) (both corrected p<0.001), and middle temporal and parahippocampal gyrus (MTG/PHG)(corrected p<0.010). During the 2-back, ELS was associated with greater activation in the IPL, MTG/PHG and inferior frontal gyrus (corrected p<0.001), with a trend towards precuneus activation (p=0.080). These findings support previous research showing that ELS is associated with impaired neurobehavioral performance and changes in brain activation, suggesting recruitment of additional cognitive resources during WM in ELS. Based on these findings, ELS screening in future WM imaging studies appears warranted. PMID:25804310

  11. Exposure to childhood trauma is associated with altered n-back activation and performance in healthy adults: implications for a commonly used working memory task.

    PubMed

    Philip, Noah S; Sweet, Lawrence H; Tyrka, Audrey R; Carpenter, S Louisa; Albright, Sarah E; Price, Lawrence H; Carpenter, Linda L

    2016-03-01

    Previous research suggests that a history of early life stress (ELS) impacts working memory (WM) in adulthood. Despite the widespread use of WM paradigms, few studies have evaluated whether ELS exposure, in the absence of psychiatric illness, also impacts WM-associated brain activity in ways that might improve sensitivity to these ELS effects or provide insights into the mechanisms of these effects. This study evaluated whether ELS affects WM behavioral performance and task-associated activity by acquiring 3T functional images from 27 medication-free healthy adults (14 with ELS) during an N-back WM task that included 0- and 2-back components. Whole brain voxel-wise analysis was performed to evaluate WM activation, followed by region of interest analyses to evaluate relationships between activation and clinical variables. ELS was associated with poorer accuracy during the 2-back (79 % ± 19 vs. 92 % ± 9, p = 0.049); accuracy and response time otherwise did not differ between groups. During the 0-back, ELS participants demonstrated increased activation in the superior temporal gyrus/insula, left inferior parietal lobule (IPL) (both corrected p < 0.001), and middle temporal and parahippocampal gyrus (MTG/PHG)(corrected p < 0.010). During the 2-back, ELS was associated with greater activation in the IPL, MTG/PHG and inferior frontal gyrus (corrected p < 0.001), with a trend towards precuneus activation (p = 0.080). These findings support previous research showing that ELS is associated with impaired neurobehavioral performance and changes in brain activation, suggesting recruitment of additional cognitive resources during WM in ELS. Based on these findings, ELS screening in future WM imaging studies appears warranted. PMID:25804310

  12. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    PubMed Central

    Mitchell, Jade; Pabon, Nicolas; Collier, Zachary A.; Egeghy, Peter P.; Cohen-Hubal, Elaine; Linkov, Igor; Vallero, Daniel A.

    2013-01-01

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. PMID:23940664

  13. Genetic algorithm based task reordering to improve the performance of batch scheduled massively parallel scientific applications

    DOE PAGESBeta

    Sankaran, Ramanan; Angel, Jordan; Brown, W. Michael

    2015-04-08

    The growth in size of networked high performance computers along with novel accelerator-based node architectures has further emphasized the importance of communication efficiency in high performance computing. The world's largest high performance computers are usually operated as shared user facilities due to the costs of acquisition and operation. Applications are scheduled for execution in a shared environment and are placed on nodes that are not necessarily contiguous on the interconnect. Furthermore, the placement of tasks on the nodes allocated by the scheduler is sub-optimal, leading to performance loss and variability. Here, we investigate the impact of task placement on themore » performance of two massively parallel application codes on the Titan supercomputer, a turbulent combustion flow solver (S3D) and a molecular dynamics code (LAMMPS). Benchmark studies show a significant deviation from ideal weak scaling and variability in performance. The inter-task communication distance was determined to be one of the significant contributors to the performance degradation and variability. A genetic algorithm-based parallel optimization technique was used to optimize the task ordering. This technique provides an improved placement of the tasks on the nodes, taking into account the application's communication topology and the system interconnect topology. As a result, application benchmarks after task reordering through genetic algorithm show a significant improvement in performance and reduction in variability, therefore enabling the applications to achieve better time to solution and scalability on Titan during production.« less

  14. Genetic algorithm based task reordering to improve the performance of batch scheduled massively parallel scientific applications

    SciTech Connect

    Sankaran, Ramanan; Angel, Jordan; Brown, W. Michael

    2015-04-08

    The growth in size of networked high performance computers along with novel accelerator-based node architectures has further emphasized the importance of communication efficiency in high performance computing. The world's largest high performance computers are usually operated as shared user facilities due to the costs of acquisition and operation. Applications are scheduled for execution in a shared environment and are placed on nodes that are not necessarily contiguous on the interconnect. Furthermore, the placement of tasks on the nodes allocated by the scheduler is sub-optimal, leading to performance loss and variability. Here, we investigate the impact of task placement on the performance of two massively parallel application codes on the Titan supercomputer, a turbulent combustion flow solver (S3D) and a molecular dynamics code (LAMMPS). Benchmark studies show a significant deviation from ideal weak scaling and variability in performance. The inter-task communication distance was determined to be one of the significant contributors to the performance degradation and variability. A genetic algorithm-based parallel optimization technique was used to optimize the task ordering. This technique provides an improved placement of the tasks on the nodes, taking into account the application's communication topology and the system interconnect topology. As a result, application benchmarks after task reordering through genetic algorithm show a significant improvement in performance and reduction in variability, therefore enabling the applications to achieve better time to solution and scalability on Titan during production.

  15. Workflow Modelling and Analysis Based on the Construction of Task Models

    PubMed Central

    Cravo, Glória

    2015-01-01

    We describe the structure of a workflow as a graph whose vertices represent tasks and the arcs are associated to workflow transitions in this paper. To each task an input/output logic operator is associated. Furthermore, we associate a Boolean term to each transition present in the workflow. We still identify the structure of workflows and describe their dynamism through the construction of new task models. This construction is very simple and intuitive since it is based on the analysis of all tasks present on the workflow that allows us to describe the dynamism of the workflow very easily. So, our approach has the advantage of being very intuitive, which is an important highlight of our work. We also introduce the concept of logical termination of workflows and provide conditions under which this property is valid. Finally, we provide a counter-example which shows that a conjecture presented in a previous article is false. PMID:25705713

  16. Supporting task-oriented collaboration in human-robot teams using semantic-based path planning

    NASA Astrophysics Data System (ADS)

    Yi, Daqing; Goodrich, Michael A.

    2014-06-01

    Improvements in robot autonomy are changing the human-robot interaction from low-level manipulation to high-level task-based collaboration. For a task-oriented collaboration, a human assigns sub-tasks to robot team members. In this paper, we consider task-oriented collaboration of humans and robots in a cordon and search problem. We focus on a path-planning framework with natural language input. By the semantic elements in a shared mental model, a natural language command can be converted into optimization objectives. We import multi-objective optimization to facilitate modeling the "adverb" elements in natural language commands. Finally, human interactions are involved in the optimization search process in order to guarantee that the found solution correctly reflects the human's intent.

  17. UMTS Base Station-like Exposure, Well-Being, and Cognitive Performance

    PubMed Central

    Regel, Sabine J.; Negovetic, Sonja; Röösli, Martin; Berdiñas, Veronica; Schuderer, Jürgen; Huss, Anke; Lott, Urs; Kuster, Niels; Achermann, Peter

    2006-01-01

    Background Radio-frequency electromagnetic fields (RF EMF) of mobile communication systems are widespread in the living environment, yet their effects on humans are uncertain despite a growing body of literature. Objectives We investigated the influence of a Universal Mobile Telecommunications System (UMTS) base station-like signal on well-being and cognitive performance in subjects with and without self-reported sensitivity to RF EMF. Methods We performed a controlled exposure experiment (45 min at an electric field strength of 0, 1, or 10 V/m, incident with a polarization of 45° from the left back side of the subject, weekly intervals) in a randomized, double-blind crossover design. A total of 117 healthy subjects (33 self-reported sensitive, 84 nonsensitive subjects) participated in the study. We assessed well-being, perceived field strength, and cognitive performance with questionnaires and cognitive tasks and conducted statistical analyses using linear mixed models. Organ-specific and brain tissue–specific dosimetry including uncertainty and variation analysis was performed. Results In both groups, well-being and perceived field strength were not associated with actual exposure levels. We observed no consistent condition-induced changes in cognitive performance except for two marginal effects. At 10 V/m we observed a slight effect on speed in one of six tasks in the sensitive subjects and an effect on accuracy in another task in nonsensitive subjects. Both effects disappeared after multiple end point adjustment. Conclusions In contrast to a recent Dutch study, we could not confirm a short-term effect of UMTS base station-like exposure on well-being. The reported effects on brain functioning were marginal and may have occurred by chance. Peak spatial absorption in brain tissue was considerably smaller than during use of a mobile phone. No conclusions can be drawn regarding short-term effects of cell phone exposure or the effects of long-term base station-like exposure on human health. PMID:16882538

  18. Biomonitoring Hexamethylene Diisocyanate (HDI) Exposure Based on Serum Levels of HDI-Specific IgG

    PubMed Central

    Wisnewski, Adam V.; Stowe, Meredith H.; Nerlinger, Abby; Opare-addo, Paul; Decamp, David; Kleinsmith, Christopher R.; Redlich, Carrie A.

    2012-01-01

    Objectives: Isocyanate chemicals essential for polyurethane production are widely used industrially, and are increasingly found in consumer products. Asthma and other adverse health effects of isocyanates are well-documented and exposure surveillance is crucial to disease prevention. Hexamethylene diisocyanate (HDI)-specific serum immunoglobulin G (IgG) was evaluated as an exposure biomarker among workers at a US Air Force Air Logistics Center, which includes a large aircraft maintenance facility. Methods: HDI-specific IgG (HDI-IgG) titers in serum samples (n = 74) were measured using an enzyme-linked immunosorbent assay based upon the biuret form of HDI conjugated to human albumin. Information on personal protective equipment (PPE), work location/tasks, smoking, asthma history, basic demographics, and HDI skin exposure was obtained through questionnaire. Results: HDI-specific serum IgG levels were elevated in n = 17 (23%) of the workers studied. The prevalence and/or end-titer of the HDI-IgG was significantly (P < 0.05) associated with specific job titles, self-reported skin exposure, night-shift work, and respirator use, but not atopy, asthma, or other demographic information. The highest titers were localized to specific worksites (C-130 painting), while other worksites (generator painting) had no or few workers with detectable HDI-IgG. Conclusions: HDI-specific immune responses (IgG) provide a practical biomarker to aid in exposure surveillance and ongoing industrial hygiene efforts. The strategy may supplement current air sampling approaches, which do not assess exposures via skin, or variability in PPE use or effectiveness. The approach may also be applicable to evaluating isocyanate exposures in other settings, and may extend to other chemical allergens. PMID:22449630

  19. Meaning-Based Scoring: A Systemic Functional Linguistics Model for Automated Test Tasks

    ERIC Educational Resources Information Center

    Gleason, Jesse

    2014-01-01

    Communicative approaches to language teaching that emphasize the importance of speaking (e.g., task-based language teaching) require innovative and evidence-based means of assessing oral language. Nonetheless, research has yet to produce an adequate assessment model for oral language (Chun 2006; Downey et al. 2008). Limited by automatic speech…

  20. Collaborative Scaffolding in Online Task-Based Voice Interactions between Advanced Learners

    ERIC Educational Resources Information Center

    Kenning, Marie-Madeleine

    2010-01-01

    This paper reports some of the findings of a distinctive innovative use of audio-conferencing involving a population (campus-based advanced learners) and a type of application (task-based language learning) that have received little attention to date: the use of Wimba Voice Tools to provide additional opportunities for spoken interactions between

  1. Meaning-Based Scoring: A Systemic Functional Linguistics Model for Automated Test Tasks

    ERIC Educational Resources Information Center

    Gleason, Jesse

    2014-01-01

    Communicative approaches to language teaching that emphasize the importance of speaking (e.g., task-based language teaching) require innovative and evidence-based means of assessing oral language. Nonetheless, research has yet to produce an adequate assessment model for oral language (Chun 2006; Downey et al. 2008). Limited by automatic speech

  2. Conducting Task-Based Interviews with Pairs of Children: Consensus, Conflict, Knowledge Construction and Turn Taking

    ERIC Educational Resources Information Center

    Houssart, Jenny; Evens, Hilary

    2011-01-01

    This article explores theoretical and methodological issues associated with task-based interviews conducted with pairs of children. We explore different approaches to interviews from sociological, psychological and subject-based perspectives. Our interviews, concerning mathematical questions and carried out with pairs of 10 and 11-year-olds, are…

  3. Evaluating TBLT: The Case of a Task-Based Spanish Program

    ERIC Educational Resources Information Center

    Gonzlez-Lloret, Marta; Nielson, Katharine B.

    2015-01-01

    The need for foreign language education in the US has increased in recent years, and teaching methods based on traditional textbooks are unlikely to meet the real-world needs of current learners. As a response, interest in Language for Specific Purposes programs has grown and so has Task-Based Language Teaching (TBLT) methodology. This article

  4. Collaborative Scaffolding in Online Task-Based Voice Interactions between Advanced Learners

    ERIC Educational Resources Information Center

    Kenning, Marie-Madeleine

    2010-01-01

    This paper reports some of the findings of a distinctive innovative use of audio-conferencing involving a population (campus-based advanced learners) and a type of application (task-based language learning) that have received little attention to date: the use of Wimba Voice Tools to provide additional opportunities for spoken interactions between…

  5. TESS-based dose-response using pediatric clonidine exposures

    SciTech Connect

    Benson, Blaine E. . E-mail: jebenson@salud.unm.edu; Spyker, Daniel A.; Troutman, William G.; Watson, William A. . E-mail: http://www.aapcc.org/

    2006-06-01

    Objective: The toxic and lethal doses of clonidine in children are unclear. This study was designed to determine whether data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) could be utilized to determine a dose-response relationship for pediatric clonidine exposure. Methods: 3458 single-substance clonidine exposures in children <6 years of age reported to TESS from January 2000 through December 2003 were examined. Dose ingested, age, and medical outcome were available for 1550 cases. Respiratory arrest cases (n = 8) were classified as the most severe of the medical outcome categories (Arrest, Major, Moderate, Mild, and No effect). Exposures reported as a 'taste or lick' (n = 51) were included as a dose of 1/10 of the dosage form involved. Dose ranged from 0.4 to 1980 (median 13) {mu}g/kg. Weight was imputed based on a quadratic estimate of weight for age. Dose certainty was coded as exact (26% of cases) or not exact (74%). Medical outcome (response) was examined via logistic regression using SAS JMP (release 5.1). Results: The logistic model describing medical outcome (P < 0.0001) included Log dose/kg (P 0.0000) and Certainty (P = 0.045). Conclusion: TESS data can provide the basis for a statistically sound description of dose-response for pediatric clonidine poisoning exposures.

  6. An augmented reality (AR)-based vocational task prompting system for people with cognitive impairments.

    PubMed

    Chang, Yao-Jen; Kang, Ya-Shu; Huang, Po-Chiao

    2013-10-01

    This study assessed the possibility of training three people with cognitive impairments using an augmented reality (AR)-based task prompting system. Using AR technology, the system provided picture cues, identified incorrect task steps on the fly, and helped users make corrections. Based on a multiple baseline design, the data showed that the three participants considerably increased their target response, which improved their vocational job skills during the intervention phases and enabled them to maintain the acquired job skills after intervention. The practical and developmental implications of the results are discussed. PMID:23880030

  7. Performance of the Rayleigh task based on the posterior probability of tomographic reconstructions

    SciTech Connect

    Hanson, K.M.

    1991-01-01

    We seek the best possible performance of the Rayleigh task in which one must decide whether a perceived object is a pair of Gaussian-blurred points or a blurred line. Two Bayesian reconstruction algorithms are used, the first based on a Gaussian prior-probability distribution with a nonnegativity constraint and the second based on an entropic prior. In both cases, the reconstructions are found that maximize the posterior probability. We compare the performance of the Rayleigh task obtained with two decision variables, the logarithm of the posterior probability ratio and the change in the mean-squared deviation from the reconstruction. The method of evaluation is based on the results of a numerical testing procedure in which the stated discrimination task is carried out on reconstructions of a randomly generated sequence of images. The ability to perform the Rayleigh task is summarized in terms of a discrimination index that is derived from the area under the receiver-operating characteristic (ROC) curve. We find that the use of the posterior probability does not result in better performance of the Rayleigh task than the mean-squared deviation from the reconstruction. 10 refs., 6 figs.

  8. A Bayesian formulation for auction-based task allocation in heterogeneous multi-agent teams

    NASA Astrophysics Data System (ADS)

    Pippin, Charles E.; Christensen, Henrik

    2011-06-01

    In distributed, heterogeneous, multi-agent teams, agents may have different capabilities and types of sensors. Agents in dynamic environments will need to cooperate in real-time to perform tasks with minimal costs. Some example scenarios include dynamic allocation of UAV and UGV robot teams to possible hurricane survivor locations, search and rescue and target detection. Auction based algorithms scale well because agents generally only need to communicate bid information. In addition, the agents are able to perform their computations in parallel and can operate on local information. Furthermore, it is easy to integrate humans and other vehicle types and sensor combinations into an auction framework. However, standard auction mechanisms do not explicitly consider sensors with varying reliability. The agents sensor qualities should be explicitly accounted. Consider a scenario with multiple agents, each carrying a single sensor. The tasks in this case are to simply visit a location and detect a target. The sensors are of varying quality, with some having a higher probability of target detection. The agents themselves may have different capabilities, as well. The agents use knowledge of their environment to submit cost-based bids for performing each task and an auction is used to perform the task allocation. This paper discusses techniques for including a Bayesian formulation of target detection likelihood into this auction based framework for performing task allocation across multi-agent heterogeneous teams. Analysis and results of experiments with multiple air systems performing distributed target detection are also included.

  9. A Consensus-Based Grouping Algorithm for Multi-agent Cooperative Task Allocation with Complex Requirements.

    PubMed

    Hunt, Simon; Meng, Qinggang; Hinde, Chris; Huang, Tingwen

    2014-01-01

    This paper looks at consensus algorithms for agent cooperation with unmanned aerial vehicles. The foundation is the consensus-based bundle algorithm, which is extended to allow multi-agent tasks requiring agents to cooperate in completing individual tasks. Inspiration is taken from the cognitive behaviours of eusocial animals for cooperation and improved assignments. Using the behaviours observed in bees and ants inspires decentralised algorithms for groups of agents to adapt to changing task demand. Further extensions are provided to improve task complexity handling by the agents with added equipment requirements and task dependencies. We address the problems of handling these challenges and improve the efficiency of the algorithm for these requirements, whilst decreasing the communication cost with a new data structure. The proposed algorithm converges to a conflict-free, feasible solution of which previous algorithms are unable to account for. Furthermore, the algorithm takes into account heterogeneous agents, deadlocking and a method to store assignments for a dynamical environment. Simulation results demonstrate reduced data usage and communication time to come to a consensus on multi-agent tasks. PMID:25191527

  10. Measuring pilot workload in a moving-base simulator. I Asynchronous secondary choice-reaction task

    NASA Technical Reports Server (NTRS)

    Kantowitz, B. H.; Hart, S. G.; Bortolussi, M. R.

    1983-01-01

    The de facto method for measuring airplane pilot workload is based upon subjective ratings. While researchers agree that such subjective data should be bolstered by using objective behavioral measures, results to date have been mixed. No clear objective technique has surfaced as the metric of choice. It is believed that this difficulty is in part due to neglect of theoretical work in psychology that predicts some of the difficulties that are inherent in a futile search for 'the one and only' best secondary task to measure workload. An initial study that used both subjective ratings and an asynchronous choice-reaction secondary task was conducted to determine if such a secondary task could indeed meet the methodological constraints imposed by current theories of attention. Two variants of a flight scenario were combined with two levels of the secondary task. Appropriate single-task control conditions were also included. Results give grounds for cautious optimism but indicate that future research should use synchronous secondary tasks where possible.

  11. Human classifier: Can individuals deduce which task someone was performing based solely on their eye movements?

    PubMed

    Dodd, Michael; Bahle, Brett; Mills, Mark; Rosen, Monica; McDonnell, Gerald; MacInnes, Joseph

    2015-01-01

    Numerous investigations have revealed that eye movements and fixation locations differ as a function of how an individual is processing a scene (e.g., Castelhano et al., 2009; Dodd et al., 2009; Land & Hayhoe, 2001; Mills et al., 2011, Yarbus, 1967). As a consequence, a common question of interest is whether a participant's task can be predicted from their observed pattern of eye movements. To that end, a number of researchers have taken a cue from the machine learning literature and attempted to train a task set classifier with varying degrees of success (e.g., Borji & Itti, 2014; Greene et al., 2012; Henderson et al., 2013). In the present experiments, we examine whether human participants can effectively classify task set based on the eye movements of others and how their performance compares to that of a recent classifier (MacInnes et al., VSS, 2014). Participants view either a) the fixation locations and fixation durations of an individual scanning a scene (independent of scanpath), b) the scanpaths of an individual scanning a scene (independent of fixation durations), or c) video playback of eye movement locations (preserving scanpath and duration information), as they attempt to determine whether the original task was visual search, memorization, or pleasantness rating. Moreover, eye movement information is provided to participants under conditions in which the original scene is present, or with the original scene absent. Participants perform this task at above-chance levels though there is considerable variability in performance as a function of task type (e.g. better at identifying search), whether the scene is present or absent, and whether the original task was performed under blocked or mixed (task-switching) conditions. These results provide important insight into our understanding of scene perception and the manner in which individuals interpret the eye movements of others. Meeting abstract presented at VSS 2015. PMID:26326956

  12. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    SciTech Connect

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705; Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705; Department of Physics, Duke University, Durham, North Carolina 27705; Department of Biomedical Engineering, Duke University, Durham, North Carolina 27705 ; Lo, Joseph Y.; Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705; Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705; Department of Biomedical Engineering, Duke University, Durham, North Carolina 27705

    2014-06-15

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d{sup ′}, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d{sup ′} was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d{sup ′}, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d{sup ′} values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of inplane structures and improved signal difference in the lesion.

  13. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    PubMed Central

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

    2014-01-01

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d?, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-?lter combinations. Using a structured CIRS phantom, d? was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d?, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d? values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of inplane structures and improved signal difference in the lesion. PMID:24877819

  14. Task-based measures of image quality and their relation to radiation dose and patient risk

    PubMed Central

    Barrett, Harrison H.; Myers, Kyle J.; Hoeschen, Christoph; Kupinski, Matthew A.; Little, Mark P.

    2015-01-01

    The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discussed. Then various standard methods for specifying radiation dose are reviewed and related to the mean number of photons in the image and hence to image quality. Current knowledge of the relation between local radiation dose and the risk of various adverse effects is summarized, and some graphical depictions of the tradeoffs between image quality and risk are introduced. Then various dose-reduction strategies are discussed in terms of their effect on task-based measures of image quality. PMID:25564960

  15. Task planning and action coordination in integrated sensor-based robots

    SciTech Connect

    Chen, C.; Trivedi, M.M.

    1995-04-01

    A System Architecture for Sensor-based Intelligent Robots (SASIR) is introduced. The system architecture consists of perception, motor, task planner, knowledge-base, user interface, and supervisor modules. SASIR is constructed using a frame data structure, which provides a suitable and flexible scheme for representation and manipulation of the world model, the sensor derived information, as well as for describing the actions required for the execution of a specific task. The experimental results show the basic validity of the general architecture as well as the robust and successful performance of two working systems: (1) the Autonomous Spill Cleaning (ASC) Robotic System, and (2) ROBOSIGHT, which is capable of a range of autonomous inspection and manipulation tasks. 45 refs.

  16. Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies.

    PubMed

    Peters, Susan; Vermeulen, Roel; Portengen, Lützen; Olsson, Ann; Kendzia, Benjamin; Vincent, Raymond; Savary, Barbara; Lavoué, Jérôme; Cavallo, Domenico; Cattaneo, Andrea; Mirabelli, Dario; Plato, Nils; Fevotte, Joelle; Pesch, Beate; Brüning, Thomas; Straif, Kurt; Kromhout, Hans

    2011-11-01

    We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer. PMID:22001827

  17. What's special about task in dystonia? A voxel-based morphometry and diffusion weighted imaging study.

    PubMed

    Ramdhani, Ritesh A; Kumar, Veena; Velickovic, Miodrag; Frucht, Steven J; Tagliati, Michele; Simonyan, Kristina

    2014-08-01

    Numerous brain imaging studies have demonstrated structural changes in the basal ganglia, thalamus, sensorimotor cortex, and cerebellum across different forms of primary dystonia. However, our understanding of brain abnormalities contributing to the clinically well-described phenomenon of task specificity in dystonia remained limited. We used high-resolution magnetic resonance imaging (MRI) with voxel-based morphometry and diffusion weighted imaging with tract-based spatial statistics of fractional anisotropy to examine gray and white matter organization in two task-specific dystonia forms, writer's cramp and laryngeal dystonia, and two non-task-specific dystonia forms, cervical dystonia and blepharospasm. A direct comparison between both dystonia forms indicated that characteristic gray matter volumetric changes in task-specific dystonia involve the brain regions responsible for sensorimotor control during writing and speaking, such as primary somatosensory cortex, middle frontal gyrus, superior/inferior temporal gyrus, middle/posterior cingulate cortex, and occipital cortex as well as the striatum and cerebellum (lobules VI-VIIa). These gray matter changes were accompanied by white matter abnormalities in the premotor cortex, middle/inferior frontal gyrus, genu of the corpus callosum, anterior limb/genu of the internal capsule, and putamen. Conversely, gray matter volumetric changes in the non-task-specific group were limited to the left cerebellum (lobule VIIa) only, whereas white matter alterations were found to underlie the primary sensorimotor cortex, inferior parietal lobule, and middle cingulate gyrus. Distinct microstructural patterns in task-specific and non-task-specific dystonias may represent neuroimaging markers and provide evidence that these two dystonia subclasses likely follow divergent pathophysiological mechanisms precipitated by different triggers. PMID:24925463

  18. Brain Computer Interface based robotic rehabilitation with online modification of task speed.

    PubMed

    Sarac, Mine; Koyas, Ela; Erdogan, Ahmetcan; Cetin, Mujdat; Patoglu, Volkan

    2013-06-01

    We present a systematic approach that enables online modification/adaptation of robot assisted rehabilitation exercises by continuously monitoring intention levels of patients utilizing an electroencephalogram (EEG) based Brain-Computer Interface (BCI). In particular, we use Linear Discriminant Analysis (LDA) to classify event-related synchronization (ERS) and desynchronization (ERD) patterns associated with motor imagery; however, instead of providing a binary classification output, we utilize posterior probabilities extracted from LDA classifier as the continuous-valued outputs to control a rehabilitation robot. Passive velocity field control (PVFC) is used as the underlying robot controller to map instantaneous levels of motor imagery during the movement to the speed of contour following tasks. In other words, PVFC changes the speed of contour following tasks with respect to intention levels of motor imagery. PVFC also allows decoupling of the task and the speed of the task from each other, and ensures coupled stability of the overall robot patient system. The proposed framework is implemented on AssistOn-Mobile--a series elastic actuator based on a holonomic mobile platform, and feasibility studies with healthy volunteers have been conducted test effectiveness of the proposed approach. Giving patients online control over the speed of the task, the proposed approach ensures active involvement of patients throughout exercise routines and has the potential to increase the efficacy of robot assisted therapies. PMID:24187241

  19. Adaptation of task difficulty in rehabilitation exercises based on the user's motor performance and physiological responses.

    PubMed

    Shirzad, Navid; Van der Loos, H F Machiel

    2013-06-01

    Although robot-assisted rehabilitation regimens are as effective, functionally, as conventional therapies, they still lack features to increase patients' engagement in the regimen. Providing rehabilitation tasks at a "desirable difficulty" is one of the ways to address this issue and increase the motivation of a patient to continue with the therapy program. Then the problem is to design a system that is capable of estimating the user's desirable difficulty, and ultimately, modifying the task based on this prediction. In this paper we compared the performance of three machine learning algorithms in predicting a user's desirable difficulty during a typical reaching motion rehabilitation task. Different levels of error amplification were used as different levels of task difficulty. We explored the usefulness of using participants' motor performance and physiological signals during the reaching task in prediction of their desirable difficulties. Results showed that a Neural Network approach gives higher prediction accuracy in comparison with models based on k-Nearest Neighbor and Discriminant Analysis methods. PMID:24187247

  20. Automated Classification of fMRI Data Employing Trial-based Imagery Tasks

    PubMed Central

    Lee, Jong-Hwan; Marzelli, Matthew; Jolesz, Ferenc A.; Yoo, Seung-Schik

    2009-01-01

    Automated interpretation and classification of functional MRI (fMRI) data is an emerging research field that enables the characterization of underlying cognitive processes with minimal human intervention. In this work, we present a method for the automated classification of human thoughts reflected on a trial-based paradigm using fMRI with a significantly shortened data acquisition time (less than one minute). Based on our preliminary experience with various cognitive imagery tasks, six characteristic thoughts were chosen as target tasks for the present work: right hand motor imagery, left hand motor imagery, right foot motor imagery, mental calculation, internal speech/word generation, and visual imagery. These six tasks were performed by five healthy volunteers and functional images were obtained using a T2*-weighted echo planar imaging (EPI) sequence. Feature vectors from activation maps, necessary for the classification of neural activity, were automatically extracted from the regions that were consistently and exclusively activated for a given task during the training process. Extracted feature vectors were classified using the support vector machine (SVM) algorithm. Parameter optimization, using a k-fold cross-validation scheme, allowed the successful recognition of the six different categories of administered thought tasks with an accuracy of 74.5% (mean) ± 14.3% (standard deviation) across all five subjects. Our proposed study for the automated classification of fMRI data may be utilized in further investigations to monitor/identify human thought processes and their potential link to hardware/computer control. PMID:19233711

  1. The Effects of Recognition and Recall Study Tasks with Feedback in a Computer-based Vocabulary Lesson.

    ERIC Educational Resources Information Center

    Clariana, Roy B.; Lee, Doris

    2001-01-01

    Focusing on whether computer-based study tasks should use multiple-choice or constructed-response (CR) question formats, this study hypothesized that a CR task with feedback would be superior to multiple-choice study tasks that allowed either single or multiple tries (STF, MTF). As hypothesized, CR scores were larger than MTF and STF scores,…

  2. Task-Based Oral Computer-Mediated Communication and L2 Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Yanguas, Inigo

    2012-01-01

    The present study adds to the computer-mediated communication (CMC) literature by exploring oral learner-to-learner interaction using Skype, a free and widely used Internet software program. In particular, this task-based study has a two-fold goal. Firstly, it explores possible differences between two modes of oral CMC (audio and video) and…

  3. Task-Based Oral Computer-Mediated Communication and L2 Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Yanguas, Inigo

    2012-01-01

    The present study adds to the computer-mediated communication (CMC) literature by exploring oral learner-to-learner interaction using Skype, a free and widely used Internet software program. In particular, this task-based study has a two-fold goal. Firstly, it explores possible differences between two modes of oral CMC (audio and video) and

  4. Task-Based Learning and Content and Language Integrated Learning Materials Design: Process and Product

    ERIC Educational Resources Information Center

    Moore, Pat; Lorenzo, Francisco

    2015-01-01

    Content and language integrated learning (CLIL) represents an increasingly popular approach to bilingual education in Europe. In this article, we describe and discuss a project which, in response to teachers' pleas for materials, led to the production of a significant bank of task-based primary and secondary CLIL units for three L2s (English,…

  5. Language Form, Task-Based Language Teaching, and the Classroom Context

    ERIC Educational Resources Information Center

    Batstone, Rob

    2012-01-01

    In this article, I examine some of the ideas about task-based language teaching (TBLT) which have emerged over the 17 years of the current editorship of ELTJ, focusing in particular on grammar and vocabulary, and enquiring to what degree these ideas take adequate account of classroom context. Over this period, TBLT scholars have built up a

  6. Learning New Grammatical Structures in Task-Based Language Learning: The Effects of Recasts and Prompts

    ERIC Educational Resources Information Center

    Van de Guchte, Marrit; Braaksma, Martine; Rijlaarsdam, Gert; Bimmel, Peter

    2015-01-01

    In the present study, we examine the effects of prompts and recasts on the acquisition of two new and different grammar structures in a task-based learning environment. Sixty-four 14-year-old 9th grade students (low intermediate) learning German as a foreign language were randomly assigned to three conditions: two experimental groups (one…

  7. Task-Based Language Teaching: Responses from Chinese Teachers of English

    ERIC Educational Resources Information Center

    Hu, Ran

    2013-01-01

    The Task-based Language Teaching (TBLT) method has been the proposed teaching method under the current national English curriculum since 2001. However, few studies have investigated in-service teachers' response to this proposed language teaching method. In this study, thirty public school English teachers were recruited in Beijing across school…

  8. Addressing the Intercultural via Task-Based Language Teaching: Possibility or Problem?

    ERIC Educational Resources Information Center

    East, Martin

    2012-01-01

    A frequent weakness of communicative approaches to foreign language teaching is a neglect of the intercultural dimension. Cultural knowledge is often treated as an addendum which focuses on learning facts about the target country. This article explores whether task-based language teaching (TBLT) can successfully address the intercultural…

  9. Efficacy of Task-Based Learning in a Chinese EFL Classroom: A Case Study

    ERIC Educational Resources Information Center

    Tang, Hersong; Chiou, Jer-Shiou; Jarsaillon, Oliver

    2015-01-01

    This study investigated how task-based learning (TBL) developed the verbal competence of Chinese learners of English as a foreign language (EFL) by employing qualitative and quantitative analyses. We compared the impromptu oral presentations on reading texts of 76 intermediate EFL learners given respectively in the beginning and the end of the…

  10. Using Virtual Reality for Task-Based Exercises in Teaching Non-Traditional Students of German

    ERIC Educational Resources Information Center

    Libbon, Stephanie

    2004-01-01

    Using task-based exercises that required web searches and online activities, this course introduced non-traditional students to the sights and sounds of the German culture and language and simultaneously to computer technology. Through partner work that required negotiation of the net as well as of the language, these adult beginning German…

  11. Reflecting on the Japan-Chile Task-Based Telecollaboration Project for Beginner-Level Learners

    ERIC Educational Resources Information Center

    Dunne, B. Greg

    2014-01-01

    Using O'Dowd and Ritter's (2006) Inventory of Reasons for Failed Communication in Telecollaborative Projects as a barometer, this article details the considerations and procedures followed in a task-based, asynchronous email telecollaboration project between EFL (English as a Foreign Language) learners in Japan and Chile. In a climate…

  12. Evaluating Integrated Task Based Activities and Computer Assisted Language Learning (CALL)

    ERIC Educational Resources Information Center

    Anwar, Khoirul; Husniah, Rohmy

    2016-01-01

    This study is to evaluate the implementation of Task Activities based on CALL which consist of observing, questioning, exploring, and communicating. The developed materials are nine chapters that had been implemented in two different classes of SMPN 1 Gresik and SMPM 4 Gresik in Indonesia. Of quesionnaires and interviews, the results indicate that…

  13. Addressing the Intercultural via Task-Based Language Teaching: Possibility or Problem?

    ERIC Educational Resources Information Center

    East, Martin

    2012-01-01

    A frequent weakness of communicative approaches to foreign language teaching is a neglect of the intercultural dimension. Cultural knowledge is often treated as an addendum which focuses on learning facts about the target country. This article explores whether task-based language teaching (TBLT) can successfully address the intercultural

  14. ESL Students' Interaction in Second Life: Task-Based Synchronous Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Jee, Min Jung

    2010-01-01

    The purpose of the present study was to explore ESL students' interactions in task-based synchronous computer-mediated communication (SCMC) in Second Life, a virtual environment by which users can interact through representational figures. I investigated Low-Intermediate and High-Intermediate ESL students' interaction patterns before, during, and…

  15. The Impact of Task-Based Approach on Vocabulary Learning in ESP Courses

    ERIC Educational Resources Information Center

    Sarani, Abdullah; Sahebi, Leila Farzaneh

    2012-01-01

    This study investigates the teaching of vocabulary in ESP courses within the paradigm of task-based language teaching, concentrating on Persian literature students at Birjand University in Iran. Two homogenous groups of students who were taking their ESP courses participated in the study as a control and an experimental group. A teacher-made test…

  16. The Impact of "Role Play" on Fostering EFL Learners' Speaking Ability: A Task-Based Approach

    ERIC Educational Resources Information Center

    Aliakbari, Mohammad; Jamalvandi, Behroz

    2010-01-01

    Marking as one dramatic turnover in language teaching, task-based language teaching (TBLT) has proved itself beneficial and effective in bringing about real situations of language use to take place and in satisfying communicative needs of learners while the former methods were unable to meet actual demands of learners to communicate in the target…

  17. Design and Analysis in Task-Based Language Assessment. CSE Technical Report.

    ERIC Educational Resources Information Center

    Mislevy, Robert J.; Steinberg, Linda S.; Almond, Russell G.

    Task-based language assessment (TBLA) grows from the observation that mastering the grammar and lexicon of a language is not sufficient for using a language to achieve ends in social situations. In TBLA, language use is observed in settings that are more realistic and complex than in discrete skills assessment and that typically require the…

  18. Task-Based Learning and Teaching in China: Secondary School Teachers' Beliefs and Practices

    ERIC Educational Resources Information Center

    Zheng, Xinmin; Borg, Simon

    2014-01-01

    While much has been written about task-based language teaching (TBLT), research examining teachers' understandings of what TBLT means remains limited. This article explores the understandings of TBLT of three Chinese secondary school teachers of English and the implementation of TBLT in their lessons. Narrative accounts were constructed for…

  19. Implementation of Task-Based Language Teaching in Chinese as a Foreign Language: Benefits and Challenges

    ERIC Educational Resources Information Center

    Bao, Rui; Du, Xiangyun

    2015-01-01

    Task-based language teaching (TBLT) has been drawing increased attention from language teachers and researchers in the past decade. This paper focuses on the effects of TBLT on beginner learners of Chinese as a foreign language (CFL) in Denmark. Participatory observation and semi-structured interviews were carried out with 18 participants from two…

  20. Task-Based Language Teaching in Online Ab Initio Foreign Language Classrooms

    ERIC Educational Resources Information Center

    Lai, Chun; Zhao, Yong; Wang, Jiawen

    2011-01-01

    Task-based language teaching (TBLT) has been attracting the attention of researchers for more than 2 decades. Research on various aspects of TBLT has been accumulating, including the evaluation studies on the implementation of TBLT in classrooms. The evaluation studies on students' and teachers' reactions to TBLT in the online courses are starting…

  1. Evaluating Gaze-Based Interface Tools to Facilitate Point-and-Select Tasks with Small Targets

    ERIC Educational Resources Information Center

    Skovsgaard, Henrik; Mateo, Julio C.; Hansen, John Paulin

    2011-01-01

    Gaze interaction affords hands-free control of computers. Pointing to and selecting small targets using gaze alone is difficult because of the limited accuracy of gaze pointing. This is the first experimental comparison of gaze-based interface tools for small-target (e.g. less than 12 x 12 pixels) point-and-select tasks. We conducted two…

  2. A Feasibility Study of Task-Based Teaching of College English Writing in Chinese EFL Context

    ERIC Educational Resources Information Center

    Cao, Linying

    2012-01-01

    In this study the author draws on Jane Willis' TBL framework and examines its effects on the improvement of EFL learners' writing competence when such a framework is applied to college writing classrooms in Chinese EFL settings, and thus tentatively explores the feasibility of the task-based approach to the teaching of EFL writing. Results of this…

  3. Pedagogical Values of Mobile-Assisted Task-Based Activities to Enhance Speaking Skill

    ERIC Educational Resources Information Center

    Mohammadi, Mojtaba; Safdari, Nastaran

    2015-01-01

    The purpose of the present study was to examine the impact of online mobile-assisted task-based activities on improving Iranian intermediate English as a Foreign Language (EFL) learners' speaking skills. To achieve the purpose of the study, 90 intermediate language learners were selected ranging between 13 to 16 years old and divided into three…

  4. Where Is It? How Deaf Adolescents Complete Fact-Based Internet Search Tasks

    ERIC Educational Resources Information Center

    Smith, Chad E.

    2007-01-01

    An exploratory study was designed to describe Internet search behaviors of deaf adolescents who used Internet search engines to complete fact-based search tasks. The study examined search behaviors of deaf high school students such as query formation, query modification, Web site identification, and Web site selection. Consisting of two fact-based…

  5. Task-Based Learning and Content and Language Integrated Learning Materials Design: Process and Product

    ERIC Educational Resources Information Center

    Moore, Pat; Lorenzo, Francisco

    2015-01-01

    Content and language integrated learning (CLIL) represents an increasingly popular approach to bilingual education in Europe. In this article, we describe and discuss a project which, in response to teachers' pleas for materials, led to the production of a significant bank of task-based primary and secondary CLIL units for three L2s (English,

  6. Evaluating Gaze-Based Interface Tools to Facilitate Point-and-Select Tasks with Small Targets

    ERIC Educational Resources Information Center

    Skovsgaard, Henrik; Mateo, Julio C.; Hansen, John Paulin

    2011-01-01

    Gaze interaction affords hands-free control of computers. Pointing to and selecting small targets using gaze alone is difficult because of the limited accuracy of gaze pointing. This is the first experimental comparison of gaze-based interface tools for small-target (e.g. less than 12 x 12 pixels) point-and-select tasks. We conducted two

  7. Professional Task-Based Curriculum Development for Distance Education Practitioners at Master's Level: A Design-Based Research

    ERIC Educational Resources Information Center

    Feng, Xiaoying; Lu, Guangxin; Yao, Zhihong

    2015-01-01

    Curriculum development for distance education (DE) practitioners is more and more focusing on practical requirements and competence development. Delphi and DACUM methods have been used at some universities. However, in the competency-based development area, these methods have been taken over by professional-task-based development in the last…

  8. Evaluation of a task-based community oriented teaching model in family medicine for undergraduate medical students in Iraq

    PubMed Central

    Al-Dabbagh, Samim A; Al-Taee, Waleed G

    2005-01-01

    Background The inclusion of family medicine in medical school curricula is essential for producing competent general practitioners. The aim of this study is to evaluate a task-based, community oriented teaching model of family medicine for undergraduate students in Iraqi medical schools. Methods An innovative training model in family medicine was developed based upon tasks regularly performed by family physicians providing health care services at the Primary Health Care Centre (PHCC) in Mosul, Iraq. Participants were medical students enrolled in their final clinical year. Students were assigned to one of two groups. The implementation group (28 students) was exposed to the experimental model and the control group (56 students) received the standard teaching curriculum. The study took place at the Mosul College of Medicine and at the Al-Hadba PHCC in Mosul, Iraq, during the academic year 1999–2000. Pre- and post-exposure evaluations comparing the intervention group with the control group were conducted using a variety of assessment tools. Results The primary endpoints were improvement in knowledge of family medicine and development of essential performance skills. Results showed that the implementation group experienced a significant increase in knowledge and performance skills after exposure to the model and in comparison with the control group. Assessment of the model by participating students revealed a high degree of satisfaction with the planning, organization, and implementation of the intervention activities. Students also highly rated the relevancy of the intervention for future work. Conclusion A model on PHCC training in family medicine is essential for all Iraqi medical schools. The model is to be implemented by various relevant departments until Departments of Family medicine are established. PMID:16115312

  9. Behavior-Based Multi-Robot Collaboration for Autonomous Construction Tasks

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghazarian, Hrand; Robinson, Matthew

    2005-01-01

    We present a heterogeneous multi-robot system for autonomous construction of a structure through assembly of long components. Placement of a component within an existing structure in a realistic environment is demonstrated on a two-robot team. The task requires component acquisition, cooperative transport, and cooperative precision manipulation. Far adaptability, the system is designed as a behavior-based architecture. Far applicability to space-related construction efforts, computation, power, communication, and sensing are minimized, though the techniques developed are also applicable to terrestrial construction tasks.

  10. DIETARY EXPOSURE METHODS AND MODELS

    EPA Science Inventory

    The research reported in this task description constitutes the MCEARD base dietary exposure research program and is conducted to complement the NERL aggregate and cumulative exposure program. Its purpose is to reduce the level of uncertainty in exposure assessment by improving N...

  11. Task-based weights for photon counting spectral x-ray imaging

    SciTech Connect

    Bornefalk, Hans

    2011-11-15

    Purpose: To develop a framework for taking the spatial frequency composition of an imaging task into account when determining optimal bin weight factors for photon counting energy sensitive x-ray systems. A second purpose of the investigation is to evaluate the possible improvement compared to using pixel based weights. Methods: The Fourier based approach of imaging performance and detectability index d' is applied to pulse height discriminating photon counting systems. The dependency of d' on the bin weight factors is made explicit, taking into account both differences in signal and noise transfer characteristics across bins and the spatial frequency dependency of interbin correlations from reabsorbed scatter. Using a simplified model of a specific silicon detector, d' values for a high and a low frequency imaging task are determined for optimal weights and compared to pixel based weights. Results: The method successfully identifies bins where a large point spread function degrades detection of high spatial frequency targets. The method is also successful in determining how to downweigh highly correlated bins. Quantitative predictions for the simplified silicon detector model indicate that improvements in the detectability index when applying task-based weights instead of pixel based weights are small for high frequency targets, but could be in excess of 10% for low frequency tasks where scatter-induced correlation otherwise degrade detectability. Conclusions: The proposed method makes the spatial frequency dependency of complex correlation structures between bins and their effect on the system detective quantum efficiency easier to analyze and allows optimizing bin weights for given imaging tasks. A potential increase in detectability of double digit percents in silicon detector systems operated at typical CT energies (100 kVp) merits further evaluation on a real system. The method is noted to be of higher relevance for silicon detectors than for cadmium (zink) telluride detectors.

  12. Role of Task-Specific Adapted Feedback on a Computer-Based Collaborative Problem-Solving Task. CSE Report 684

    ERIC Educational Resources Information Center

    Chuang, San-hui; O'Neil, Harold F.

    2006-01-01

    Collaborative problem solving and collaborative skills are considered necessary skills for success in today's world. Collaborative problem solving is defined as problem solving activities that involve interactions among a group of individuals. Large-scale and small-scale assessment programs increasingly use collaborative group tasks in which…

  13. Resting-State and Task-Based Functional Brain Connectivity in Developmental Dyslexia

    PubMed Central

    Schurz, Matthias; Wimmer, Heinz; Richlan, Fabio; Ludersdorfer, Philipp; Klackl, Johannes; Kronbichler, Martin

    2015-01-01

    Reading requires the interaction between multiple cognitive processes situated in distant brain areas. This makes the study of functional brain connectivity highly relevant for understanding developmental dyslexia. We used seed-voxel correlation mapping to analyse connectivity in a left-hemispheric network for task-based and resting-state fMRI data. Our main finding was reduced connectivity in dyslexic readers between left posterior temporal areas (fusiform, inferior temporal, middle temporal, superior temporal) and the left inferior frontal gyrus. Reduced connectivity in these networks was consistently present for 2 reading-related tasks and for the resting state, showing a permanent disruption which is also present in the absence of explicit task demands and potential group differences in performance. Furthermore, we found that connectivity between multiple reading-related areas and areas of the default mode network, in particular the precuneus, was stronger in dyslexic compared with nonimpaired readers. PMID:25169986

  14. Aging increases flexibility of postural reactive responses based on constraints imposed by a manual task

    PubMed Central

    de Lima-Pardini, Andrea Cristina; Coelho, Daniel Boari; Silva, Marina Brito; Azzi, Nametala Maia; Martinelli, Alessandra Rezende; Horak, Fay Bahling; Teixeira, Luis Augusto

    2014-01-01

    This study compared the effect of stability constraints imposed by a manual task on the adaptation of postural responses between 16 healthy elderly (mean age = 71.56 years, SD = 7.38) and 16 healthy young (mean age = 22.94 years, SD = 4.82) individuals. Postural stability was perturbed through unexpected release of a load attached to the participant’s trunk while performing two versions of a voluntary task: holding a tray with a cylinder placed with its flat side down (low constraint) or with its rolling round side down (high constraint). Low and high constraint tasks were performed in alternate blocks of trials. Results showed that young participants adapted muscular activation and kinematics of postural responses in association with previous experience with the first block of manual task constraint, whereas the elderly modulated postural responses based on the current manual constraint. This study provides evidence for flexibility of postural strategies in the elderly to deal with constraints imposed by a manual task. PMID:25520656

  15. TBDQ: A Pragmatic Task-Based Method to Data Quality Assessment and Improvement

    PubMed Central

    Vaziri, Reza; Mohsenzadeh, Mehran; Habibi, Jafar

    2016-01-01

    Organizations are increasingly accepting data quality (DQ) as a major key to their success. In order to assess and improve DQ, methods have been devised. Many of these methods attempt to raise DQ by directly manipulating low quality data. Such methods operate reactively and are suitable for organizations with highly developed integrated systems. However, there is a lack of a proactive DQ method for businesses with weak IT infrastructure where data quality is largely affected by tasks that are performed by human agents. This study aims to develop and evaluate a new method for structured data, which is simple and practical so that it can easily be applied to real world situations. The new method detects the potentially risky tasks within a process, and adds new improving tasks to counter them. To achieve continuous improvement, an award system is also developed to help with the better selection of the proposed improving tasks. The task-based DQ method (TBDQ) is most appropriate for small and medium organizations, and simplicity in implementation is one of its most prominent features. TBDQ is case studied in an international trade company. The case study shows that TBDQ is effective in selecting optimal activities for DQ improvement in terms of cost and improvement. PMID:27192547

  16. Micro-motion exposure method based on PZT piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Sun, Wenjun; Zhang, Mei-heng; Meng, Zhong

    2009-07-01

    There mainly is laser digital photofinishing technique and digital photofinishing technique based on LCD consisting of TFT and LCOS in the digital photofinishing field at the present time. The former have a good many merit such as wide color gamut, high processing rate, large output size and high brightness, but his cost is very high, his maintain technique being comparatively complex, that result in difficult use for people. The utilization ratio of the latter is low because of lower resolution and lower aperture ratio for LCD, but the digital photofinishing based on LCD have lower cost and higher utilization ration, being suitable for people's current standard of living. Considering above mentioned problem, a micro-motion exposure method based on PZT piezoelectric ceramics used in digital image photofinishing is presented. The two-dimension micro-motion exposure system consisting of PZT piezoelectric ceramics, LCD panel, polarizing film and spring strip is designed. By means of PZT piezoelectric ceramics the LCD panel is removed about the one half of the pixel size of the LCD panel for four times from the original place, at the same time imaging system is exposed four times at the printing paper. The software is used to control the time synchronization, the exposure time and motion range of the LCD panel. The system has advantages such as shorter response time than 0.1seconds, lesser motion error than 0.01 microns, high stability and repeatability. Experimental results show that the proposed micro-motion exposure method improve the picture brightness and enlarge output size, at the meantime reducing the cost of the system.

  17. Quadrotor UAV Control for Vision-based Moving Target Tracking Task

    NASA Astrophysics Data System (ADS)

    Bohdanov, Denys

    The problem of stand-off tracking of a moving target using a quadrotor unmanned aerial vehicle (UAV) based on vision-sensing is investigated. A PID (Proportional-Integral-Derivative) controller is implemented for attitude stabilization of the quadrotor. An LQG-based (Linear-Quadratic-Gaussian) control law is designed and implemented for position control of the quadrotor for a moving target tracking task. A novel vision-based estimation algorithm is developed, enabling estimation of quadrotor's position, altitude and yaw relative to the target based on limited information about the target. Two image processing algorithms are implemented and compared for the task of feature detection and feature tracking in a series of images. Image processing algorithms are integrated with quadrotor control and experiments are performed to validate proposed control and estimation approaches.

  18. Relating UMLS semantic types and task-based ontology to computer-interpretable clinical practice guidelines.

    PubMed

    Kumar, Anand; Ciccarese, Paolo; Quaglini, Silvana; Stefanelli, Mario; Caffi, Ezio; Boiocchi, Lorenzo

    2003-01-01

    Medical knowledge in clinical practice guideline (GL) texts is the source of task-based computer-interpretable clinical guideline models (CIGMs). We have used Unified Medical Language System (UMLS) semantic types (STs) to understand the percentage of GL text which belongs to a particular ST. We also use UMLS semantic network together with the CIGM-specific ontology to derive a semantic meaning behind the GL text. In order to achieve this objective, we took nine GL texts from the National Guideline Clearinghouse (NGC) and marked up the text dealing with a particular ST. The STs we took into consideration were restricted taking into account the requirements of a task-based CIGM. We used DARPA Agent Markup Language and Ontology Inference Layer (DAML + OIL) to create the UMLS and CIGM specific semantic network. For the latter, as a bench test, we used the 1999 WHO-International Society of Hypertension Guidelines for the Management of Hypertension. We took into consideration the UMLS STs closest to the clinical tasks. The percentage of the GL text dealing with the ST "Health Care Activity" and subtypes "Laboratory Procedure", "Diagnostic Procedure" and "Therapeutic or Preventive Procedure" were measured. The parts of text belonging to other STs or comments were separated. A mapping of terms belonging to other STs was done to the STs under "HCA" for representation in DAML + OIL. As a result, we found that the three STs under "HCA" were the predominant STs present in the GL text. In cases where the terms of related STs existed, they were mapped into one of the three STs. The DAML + OIL representation was able to describe the hierarchy in task-based CIGMs. To conclude, we understood that the three STs could be used to represent the semantic network of the task-bases CIGMs. We identified some mapping operators which could be used for the mapping of other STs into these. PMID:14664031

  19. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    PubMed Central

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles A.

    2009-01-01

    The coupling of dosimetry measurements and modeling represents a promising strategy for deciphering the relationship between chemical exposure and disease outcome. To support the development and implementation of biological monitoring programs, quantitative technologies for measuring xenobiotic exposure are needed. The development of portable nanotechnology-based electrochemical sensors has the potential to meet the needs for low cost, rapid, high-throughput and ultrasensitive detectors for biomonitoring an array of chemical markers. Highly selective electrochemical (EC) sensors capable of pM sensitivity, high-throughput and low sample requirements (<50uL) are discussed. These portable analytical systems have many advantages over currently available technologies, thus potentially representing the next-generation of biomonitoring analyzers. This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are presented. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are discussed. PMID:19018275

  20. Measuring students' school context exposures: A trajectory-based approach.

    PubMed

    Halpern-Manners, Andrew

    2016-07-01

    Studies of school effects on children's outcomes usually use single time-point measures. I argue that this approach fails to account for (1) age-based variation in children's sensitivity to their surroundings; (2) differential effects stemming from differences in the length of young people's exposures; and (3) moves between contexts and endogenous changes over time within them. To evaluate the merits of this argument, I specify and test a longitudinal model of school effects on children's academic performance. Drawing on recent advances in finite mixture modeling, I identify a series of distinct school context trajectories that extend across a substantial portion of respondents' elementary and secondary school years. I find that these trajectories vary significantly with respect to shape, with some students experiencing significant changes in their environments over time. I then show that students' trajectories of exposure are related to their 8th grade achievement, even after controlling for point-in-time measures of school context. PMID:27194656

  1. A latent discriminative model-based approach for classification of imaginary motor tasks from EEG data

    NASA Astrophysics Data System (ADS)

    Delgado Saa, Jaime F.; Çetin, Müjdat

    2012-04-01

    We consider the problem of classification of imaginary motor tasks from electroencephalography (EEG) data for brain-computer interfaces (BCIs) and propose a new approach based on hidden conditional random fields (HCRFs). HCRFs are discriminative graphical models that are attractive for this problem because they (1) exploit the temporal structure of EEG; (2) include latent variables that can be used to model different brain states in the signal; and (3) involve learned statistical models matched to the classification task, avoiding some of the limitations of generative models. Our approach involves spatial filtering of the EEG signals and estimation of power spectra based on autoregressive modeling of temporal segments of the EEG signals. Given this time-frequency representation, we select certain frequency bands that are known to be associated with execution of motor tasks. These selected features constitute the data that are fed to the HCRF, parameters of which are learned from training data. Inference algorithms on the HCRFs are used for the classification of motor tasks. We experimentally compare this approach to the best performing methods in BCI competition IV as well as a number of more recent methods and observe that our proposed method yields better classification accuracy.

  2. Production Task Queue Optimization Based on Multi-Attribute Evaluation for Complex Product Assembly Workshop

    PubMed Central

    Li, Lian-hui; Mo, Rong

    2015-01-01

    The production task queue has a great significance for manufacturing resource allocation and scheduling decision. Man-made qualitative queue optimization method has a poor effect and makes the application difficult. A production task queue optimization method is proposed based on multi-attribute evaluation. According to the task attributes, the hierarchical multi-attribute model is established and the indicator quantization methods are given. To calculate the objective indicator weight, criteria importance through intercriteria correlation (CRITIC) is selected from three usual methods. To calculate the subjective indicator weight, BP neural network is used to determine the judge importance degree, and then the trapezoid fuzzy scale-rough AHP considering the judge importance degree is put forward. The balanced weight, which integrates the objective weight and the subjective weight, is calculated base on multi-weight contribution balance model. The technique for order preference by similarity to an ideal solution (TOPSIS) improved by replacing Euclidean distance with relative entropy distance is used to sequence the tasks and optimize the queue by the weighted indicator value. A case study is given to illustrate its correctness and feasibility. PMID:26414758

  3. Production Task Queue Optimization Based on Multi-Attribute Evaluation for Complex Product Assembly Workshop.

    PubMed

    Li, Lian-Hui; Mo, Rong

    2015-01-01

    The production task queue has a great significance for manufacturing resource allocation and scheduling decision. Man-made qualitative queue optimization method has a poor effect and makes the application difficult. A production task queue optimization method is proposed based on multi-attribute evaluation. According to the task attributes, the hierarchical multi-attribute model is established and the indicator quantization methods are given. To calculate the objective indicator weight, criteria importance through intercriteria correlation (CRITIC) is selected from three usual methods. To calculate the subjective indicator weight, BP neural network is used to determine the judge importance degree, and then the trapezoid fuzzy scale-rough AHP considering the judge importance degree is put forward. The balanced weight, which integrates the objective weight and the subjective weight, is calculated base on multi-weight contribution balance model. The technique for order preference by similarity to an ideal solution (TOPSIS) improved by replacing Euclidean distance with relative entropy distance is used to sequence the tasks and optimize the queue by the weighted indicator value. A case study is given to illustrate its correctness and feasibility. PMID:26414758

  4. A situated reasoning architecture for space-based repair and replace tasks

    NASA Technical Reports Server (NTRS)

    Bloom, Ben; Mcgrath, Debra; Sanborn, Jim

    1989-01-01

    Space-based robots need low level control for collision detection and avoidance, short-term load management, fine-grained motion, and other physical tasks. In addition, higher level control is required to focus strategic decision making as missions are assigned and carried out. Reasoning and control must be responsive to ongoing changes in the environment. Research aimed at bridging the gap between high level artificial intelligence (AI) planning techniques and task-level robot programming for telerobotic systems is described. Situated reasoning is incorporated into AI and Robotics systems in order to coordinate a robot's activity within its environment. An integrated system under development in a component maintenance domain is described. It is geared towards replacing worn and/or failed Orbital Replacement Units (ORUs) designed for use aboard NASA's Space Station Freedom based on the collection of components available at a given time. High level control reasons in component space in order to maximize the number operational component-cells over time, while the task-level controls sensors and effectors, detects collisions, and carries out pick and place tasks in physical space. Situated reasoning is used throughout the system to cope with component failures, imperfect information, and unexpected events.

  5. Space transportation nodes assumptions and requirements: Lunar base systems study task 2.1

    NASA Technical Reports Server (NTRS)

    Kahn, Taher Ali; Simonds, Charles H.; Stump, William R.

    1988-01-01

    The Space Transportation Nodes Assumptions and Requirements task was performed as part of the Advanced Space Transportation Support Contract, a NASA Johnson Space Center (JSC) study intended to provide planning for a Lunar Base near the year 2000. The original task statement has been revised to satisfy the following queries: (1) What vehicles are to be processed at the transportation node; (2) What is the flow of activities involved in a vehicle passing through the node; and (3) What node support resources are necessary to support a lunar scenario traffic model composed of a mix of vehicles in an active flight schedule. The Lunar Base Systems Study is concentrating on the initial years of the Phase 2 Lunar Base Scenario. The study will develop the first five years of that phase in order to define the transportation and surface systems (including mass, volumes, power requirements, and designs).

  6. Multi-tasking Schiff base ligand: a new concept of AuNPs synthesis.

    PubMed

    Abad, Jose Maria; Bravo, Iria; Pariente, Felix; Lorenzo, Encarnación

    2016-03-01

    Multi-tasking 3,4-dihydroxysalophen Schiff base tetradentate ligand (3,4-DHS) as reductant, stabilizer, and catalyst in a new concept of gold nanoparticles (AuNPs) synthesis is demonstrated. 3,4-DHS is able to reduce HAuCl4 in water, acting also as capping agent for the generation of stable colloidal suspensions of Schiff base ligand-AuNPs assemblies of controlled size by providing a robust coating to AuNPs, within a unique reaction step. Once deposited on carbon electrodes, 3,4-DHS-AuNPs assemblies show a potent electrocatalytic effect towards hydrazine oxidation and hydrogen peroxide oxidation/reduction. Graphical Abstract Multi-tasking 3,4-dihydroxysalophen Schiff base tetradentate ligand (3,4-DHS) as reductant, stabilizer, and catalyst. PMID:26922338

  7. Moving from Virtual Reality Exposure-Based Therapy to Augmented Reality Exposure-Based Therapy: A Review

    PubMed Central

    Baus, Oliver; Bouchard, Stéphane

    2014-01-01

    This paper reviews the move from virtual reality exposure-based therapy to augmented reality exposure-based therapy (ARET). Unlike virtual reality (VR), which entails a complete virtual environment (VE), augmented reality (AR) limits itself to producing certain virtual elements to then merge them into the view of the physical world. Although, the general public may only have become aware of AR in the last few years, AR type applications have been around since beginning of the twentieth century. Since, then, technological developments have enabled an ever increasing level of seamless integration of virtual and physical elements into one view. Like VR, AR allows the exposure to stimuli which, due to various reasons, may not be suitable for real-life scenarios. As such, AR has proven itself to be a medium through which individuals suffering from specific phobia can be exposed “safely” to the object(s) of their fear, without the costs associated with programing complete VEs. Thus, ARET can offer an efficacious alternative to some less advantageous exposure-based therapies. Above and beyond presenting what has been accomplished in ARET, this paper covers some less well-known aspects of the history of AR, raises some ARET related issues, and proposes potential avenues to be followed. These include the type of measures to be used to qualify the user’s experience in an augmented reality environment, the exclusion of certain AR-type functionalities from the definition of AR, as well as the potential use of ARET to treat non-small animal phobias, such as social phobia. PMID:24624073

  8. Object Retrieval in the 1st Year of Life: Learning Effects of Task Exposure and Box Transparency

    ERIC Educational Resources Information Center

    Bojczyk, Kathryn E.; Corbetta, Daniela

    2004-01-01

    Before 12 months of age, infants have difficulties coordinating and sequencing their movements to retrieve an object concealed in a box. This study examined (a) whether young infants can discover effective retrieval solutions and consolidate movement coordination earlier if exposed regularly to such a task and (b) whether different environments,…

  9. Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

    PubMed Central

    Pleil, J D; Smith, L B; Zelnick, S D

    2000-01-01

    JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10706522

  10. Forecasting exposure to volcanic ash based on ash dispersion modeling

    NASA Astrophysics Data System (ADS)

    Peterson, Rorik A.; Dean, Ken G.

    2008-03-01

    A technique has been developed that uses Puff, a volcanic ash transport and dispersion (VATD) model, to forecast the relative exposure of aircraft and ground facilities to ash from a volcanic eruption. VATD models couple numerical weather prediction (NWP) data with physical descriptions of the initial eruptive plume, atmospheric dispersion, and settling of ash particles. Three distinct examples of variations on the technique are given using ERA-40 archived reanalysis NWP data. The Feb. 2000 NASA DC-8 event involving an eruption of Hekla volcano, Iceland is first used for analyzing a single flight. Results corroborate previous analyses that conclude the aircraft did encounter a diffuse cloud of volcanic origin, and indicate exposure within a factor of 10 compared to measurements made on the flight. The sensitivity of the technique to dispersion physics is demonstrated. The Feb. 2001 eruption of Mt. Cleveland, Alaska is used as a second example to demonstrate how this technique can be utilized to quickly assess the potential exposure of a multitude of aircraft during and soon after an event. Using flight tracking data from over 40,000 routes over three days, several flights that may have encountered low concentrations of ash were identified, and the exposure calculated. Relative changes in the quantity of exposure when the eruption duration is varied are discussed, and no clear trend is evident as the exposure increased for some flights and decreased for others. A third application of this technique is demonstrated by forecasting the near-surface airborne concentrations of ash that the cities of Yakima Washington, Boise Idaho, and Kelowna British Columbia might have experienced from an eruption of Mt. St. Helens anytime during the year 2000. Results indicate that proximity to the source does not accurately determine the potential hazard. Although an eruption did not occur during this time, the results serve as a demonstration of how existing cities or potential locations of research facilities or military bases can be assessed for susceptibility to hazardous and unhealthy concentrations of ash and other volcanic gases.

  11. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    SciTech Connect

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles

    2009-01-01

    This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are discussed. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are covered.

  12. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2012-01-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  13. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2011-12-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  14. Electric Vehicle Preparedness: Task 1, Assessment of Fleet Inventory for Marine Corps Base Camp Lejeune

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-01-01

    Several U.S. Department of Defense-based studies were conducted to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 included a survey of the inventory of non-tactical fleet vehicles at the Marine Corps Base Camp Lejeune (MCBCL) to characterize the fleet. This information and characterization will be used to select vehicles for monitoring that takes place during Task 2. This monitoring involves data logging of vehicle operation in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provides observations related to placement of PEV charging infrastructure.

  15. Fisher kernel based task boundary retrieval in laparoscopic database with single video query.

    PubMed

    Twinanda, Andru Putra; De Mathelin, Michel; Padoy, Nicolas

    2014-01-01

    As minimally invasive surgery becomes increasingly popular, the volume of recorded laparoscopic videos will increase rapidly. Invaluable information for teaching, assistance during difficult cases, and quality evaluation can be accessed from these videos through a video search engine. Typically, video search engines give a list of the most relevant videos pertaining to a keyword. However, instead of a whole video, one is often only interested in a fraction of the video (e.g. intestine stitching in bypass surgeries). In addition, video search requires semantic tags, yet the large amount of data typically generated hinders the feasibility of manual annotation. To tackle these problems, we propose a coarse-to-fine video indexing approach that looks for the time boundaries of a task in a laparoscopic video based on a video snippet query. We combine our search approach with the Fisher kernel (FK) encoding and show that similarity measures on this encoding are better suited for this problem than traditional similarities, such as dynamic time warping (DTW). Despite visual challenges, such as the presence of smoke, motion blur, and lens impurity, our approach performs very well in finding 3 tasks in 49 bypass videos, 1 task in 23 hernia videos, and also 1 cross-surgery task between 49 bypass and 7 sleeve gastrectomy videos. PMID:25320826

  16. Task-based detectability in CT image reconstruction by filtered backprojection and penalized likelihood estimation

    PubMed Central

    Gang, Grace J.; Stayman, J. Webster; Zbijewski, Wojciech; Siewerdsen, Jeffrey H.

    2014-01-01

    Purpose: Nonstationarity is an important aspect of imaging performance in CT and cone-beam CT (CBCT), especially for systems employing iterative reconstruction. This work presents a theoretical framework for both filtered-backprojection (FBP) and penalized-likelihood (PL) reconstruction that includes explicit descriptions of nonstationary noise, spatial resolution, and task-based detectability index. Potential utility of the model was demonstrated in the optimal selection of regularization parameters in PL reconstruction. Methods: Analytical models for local modulation transfer function (MTF) and noise-power spectrum (NPS) were investigated for both FBP and PL reconstruction, including explicit dependence on the object and spatial location. For FBP, a cascaded systems analysis framework was adapted to account for nonstationarity by separately calculating fluence and system gains for each ray passing through any given voxel. For PL, the point-spread function and covariance were derived using the implicit function theorem and first-order Taylor expansion according toFessler [“Mean and variance of implicitly defined biased estimators (such as penalized maximum likelihood): Applications to tomography,” IEEE Trans. Image Process.41(8), 493–506 (1996)]. Detectability index was calculated for a variety of simple tasks. The model for PL was used in selecting the regularization strength parameter to optimize task-based performance, with both a constant and a spatially varying regularization map. Results: Theoretical models of FBP and PL were validated in 2D simulated fan-beam data and found to yield accurate predictions of local MTF and NPS as a function of the object and the spatial location. The NPS for both FBP and PL exhibit similar anisotropic nature depending on the pathlength (and therefore, the object and spatial location within the object) traversed by each ray, with the PL NPS experiencing greater smoothing along directions with higher noise. The MTF of FBP is isotropic and independent of location to a first order approximation, whereas the MTF of PL is anisotropic in a manner complementary to the NPS. Task-based detectability demonstrates dependence on the task, object, spatial location, and smoothing parameters. A spatially varying regularization “map” designed from locally optimal regularization can improve overall detectability beyond that achievable with the commonly used constant regularization parameter. Conclusions: Analytical models for task-based FBP and PL reconstruction are predictive of nonstationary noise and resolution characteristics, providing a valuable framework for understanding and optimizing system performance in CT and CBCT. PMID:25086533

  17. Task-based detectability in CT image reconstruction by filtered backprojection and penalized likelihood estimation

    SciTech Connect

    Gang, Grace J.; Stayman, J. Webster; Zbijewski, Wojciech; Siewerdsen, Jeffrey H.

    2014-08-15

    Purpose: Nonstationarity is an important aspect of imaging performance in CT and cone-beam CT (CBCT), especially for systems employing iterative reconstruction. This work presents a theoretical framework for both filtered-backprojection (FBP) and penalized-likelihood (PL) reconstruction that includes explicit descriptions of nonstationary noise, spatial resolution, and task-based detectability index. Potential utility of the model was demonstrated in the optimal selection of regularization parameters in PL reconstruction. Methods: Analytical models for local modulation transfer function (MTF) and noise-power spectrum (NPS) were investigated for both FBP and PL reconstruction, including explicit dependence on the object and spatial location. For FBP, a cascaded systems analysis framework was adapted to account for nonstationarity by separately calculating fluence and system gains for each ray passing through any given voxel. For PL, the point-spread function and covariance were derived using the implicit function theorem and first-order Taylor expansion according toFessler [“Mean and variance of implicitly defined biased estimators (such as penalized maximum likelihood): Applications to tomography,” IEEE Trans. Image Process. 5(3), 493–506 (1996)]. Detectability index was calculated for a variety of simple tasks. The model for PL was used in selecting the regularization strength parameter to optimize task-based performance, with both a constant and a spatially varying regularization map. Results: Theoretical models of FBP and PL were validated in 2D simulated fan-beam data and found to yield accurate predictions of local MTF and NPS as a function of the object and the spatial location. The NPS for both FBP and PL exhibit similar anisotropic nature depending on the pathlength (and therefore, the object and spatial location within the object) traversed by each ray, with the PL NPS experiencing greater smoothing along directions with higher noise. The MTF of FBP is isotropic and independent of location to a first order approximation, whereas the MTF of PL is anisotropic in a manner complementary to the NPS. Task-based detectability demonstrates dependence on the task, object, spatial location, and smoothing parameters. A spatially varying regularization “map” designed from locally optimal regularization can improve overall detectability beyond that achievable with the commonly used constant regularization parameter. Conclusions: Analytical models for task-based FBP and PL reconstruction are predictive of nonstationary noise and resolution characteristics, providing a valuable framework for understanding and optimizing system performance in CT and CBCT.

  18. Developmental Exposure to PCBs and/or MeHg: Effects on a Differential Reinforcement of Low Rates (DRL) Operant Task Before and After Amphetamine Drug Challenge

    PubMed Central

    Sable, Helen J. K.; Eubig, Paul A.; Powers, Brian E.; Wang, Victor C.; Schantz, Susan L.

    2009-01-01

    The current study assessed the effects of developmental PCB and/or MeHg exposure on an operant task of timing and inhibitory control and determined if amphetamine (AMPH) drug challenges differentially affected performance. Long-Evans rats were exposed to corn oil (control), PCBs alone (1 or 3 mg/kg), MeHg alone (1.5 or 4.5 ppm), the low combination (1 mg/kg PCBs + 1.5 ppm MeHg), or the high combination (3 mg/kg PCBs + 4.5 ppm MeHg) throughout gestation and lactation. An environmentally relevant, formulated PCB mixture was used. Male and female offspring were trained to asymptotic performance on a differential reinforcement of low rates (DRL) operant task as adults. PCB-exposed groups had a lower ratio of reinforced to non-reinforced responses than controls. Groups exposed to MeHg alone were not impaired and the deficits observed in PCB-exposed groups were not seen when PCBs were co-administered with MeHg. AMPH was less disruptive to responding in males receiving PCBs alone, MeHg alone, and 1.0 mg/kg PCB + 1.5 ppm MeHg. Paradoxically, the disruption in responding by AMPH in males given 3.0 mg/kg PCB + 4.5 ppm MeHg did not differ from controls. Exposed females from all treatment groups did not differ from controls in their AMPH response. Overall, the findings suggest that developmental exposure to PCBs can decrease DRL performance. Co-exposure to MeHg seemed to mitigate the detrimental effects of PCBs on performance. The finding that the disruptive effects of AMPH on DRL performance were lessened in some groups of exposed males suggests that alterations in dopaminergic functioning may have a role in behavioral changes seen after perinatal PCB and MeHg exposure. PMID:19344642

  19. Alpha-Linolenic Acid-Induced Increase in Neurogenesis is a Key Factor in the Improvement in the Passive Avoidance Task After Soman Exposure.

    PubMed

    Piermartiri, Tetsade C B; Pan, Hongna; Chen, Jun; McDonough, John; Grunberg, Neil; Apland, James P; Marini, Ann M

    2015-09-01

    Exposure to organophosphorous (OP) nerve agents such as soman inhibits the critical enzyme acetylcholinesterase (AChE) leading to excessive acetylcholine accumulation in synapses, resulting in cholinergic crisis, status epilepticus and brain damage in survivors. The hippocampus is profoundly damaged after soman exposure leading to long-term memory deficits. We have previously shown that treatment with three sequential doses of alpha-linolenic acid, an essential omega-3 polyunsaturated fatty acid, increases brain plasticity in naïve animals. However, the effects of this dosing schedule administered after a brain insult and the underlying molecular mechanisms in the hippocampus are unknown. We now show that injection of three sequential doses of alpha-linolenic acid after soman exposure increases the endogenous expression of mature BDNF, activates Akt and the mammalian target of rapamycin complex 1 (mTORC1), increases neurogenesis in the subgranular zone of the dentate gyrus, increases retention latency in the passive avoidance task and increases animal survival. In sharp contrast, while soman exposure also increases mature BDNF, this increase did not activate downstream signaling pathways or neurogenesis. Administration of the inhibitor of mTORC1, rapamycin, blocked the alpha-linolenic acid-induced neurogenesis and the enhanced retention latency but did not affect animal survival. Our results suggest that alpha-linolenic acid induces a long-lasting neurorestorative effect that involves activation of mTORC1 possibly via a BDNF-TrkB-mediated mechanism. PMID:25920465

  20. Exposure of baboons to combined 60 Hz electric and magnetic fields does not produce work stoppage or affect operant performance on a match-to-sample task

    SciTech Connect

    Orr, J.L.; Rogers, W.R.; Smith, H.D.

    1995-12-31

    The authors examined the effects of combined 60 Hz electric and magnetic field (EMF) exposure on performance of delayed match-to-sample (MTS) procedure involving the flash rate of a light as the stimulus. Six baboons (Papio cynocephalus) fully acquired the task; four others functioned accurately only when cued. All ten subjects were assigned to EMF-exposed or sham-exposed groups of five and were used to test for a work-stoppage effect that was previously observed with initial exposure to electric fields (EF) of 30 or 60 kV/m. Here, the authors report the results of two experiments, each consisting of 6 week preexposure, exposure, and postexposure periods. They found no evidence of work stoppage with fields of 6 kV/m and 50 {micro}T (0.5 G) or with 30 kV/m and 100 {micro}T (1.0 G). In neither experiment was there evidence of an adverse effect of 60 Hz EMF exposure on MTS performance.

  1. Confidence-based integrated reweighting model of task-difficulty explains location-based specificity in perceptual learning

    PubMed Central

    Talluri, Bharath Chandra; Hung, Shao-Chin; Seitz, Aaron R.; Seris, Peggy

    2015-01-01

    Perceptual learning is classically thought to be highly specific to the trained stimuli's retinal locations. However, recent research using a novel double-training paradigm has found dramatic transfer of perceptual learning to untrained locations. These results challenged existing models of perceptual learning and provoked intense debate in the field. Recently, Hung and Seitz (2014) showed that previously reported results could be reconciled by considering the details of the training procedure, in particular, whether it involves prolonged training at threshold using a single staircase procedure or multiple staircases. Here, we examine a hierarchical neural network model of the visual pathway, built upon previously proposed integrated reweighting models of perceptual learning, to understand how retinotopic transfer depends on the training procedure adopted. We propose that the transfer and specificity of learning between retinal locations can be explained by considering the task-difficulty and confidence during training. In our model, difficult tasks lead to higher learning of weights from early visual cortex to the decision unit, and thus to specificity, while easy tasks lead to higher learning of weights from later stages of the visual hierarchy and thus to more transfer. To model interindividual difference in task-difficulty, we relate task-difficulty to the confidence of subjects. We show that our confidence-based reweighting model can account for the results of Hung and Seitz (2014) and makes testable predictions. PMID:26720153

  2. The Relationship between Working Memory Capacity and L2 Oral Performance under Task-Based Careful Online Planning Condition

    ERIC Educational Resources Information Center

    Ahmadian, Mohammad Javad

    2012-01-01

    The study reported in this article aimed to investigate the way working memory capacity (WMC) interacts with careful online planning--a task-based implementation variable--to affect second language (L2) speech production. This issue is important to teachers, because it delves into one of the possible task-based implementation variables and thus…

  3. Structuring Job Related Information on the Intranet: An Experimental Comparison of Task vs. an Organization-Based Approach

    ERIC Educational Resources Information Center

    Cozijn, Reinier; Maes, Alfons; Schackman, Didie; Ummelen, Nicole

    2007-01-01

    In this article, we present a usability experiment in which participants were asked to make intensive use of information on an intranet in order to execute job-related tasks. Participants had to work with one of two versions of an intranet: one with an organization-based hyperlink structure, and one with a task-based hyperlink structure.…

  4. Gaining Proficiency through Task-Based Activities in the Portuguese Classroom (Beginning and Intermediate Year Case Studies)

    ERIC Educational Resources Information Center

    Jones-Kellogg, Rebecca

    2015-01-01

    This paper describes a task-based activity used at the United States Military Academy, in their first- through third-semester Portuguese language sequence "Proficiencies" (Proficincias). The stand-alone task-based activity can be an effective tool in gaining foreign-language proficiency at even the lowest levels of classroom instruction

  5. The Relationship between Working Memory Capacity and L2 Oral Performance under Task-Based Careful Online Planning Condition

    ERIC Educational Resources Information Center

    Ahmadian, Mohammad Javad

    2012-01-01

    The study reported in this article aimed to investigate the way working memory capacity (WMC) interacts with careful online planning--a task-based implementation variable--to affect second language (L2) speech production. This issue is important to teachers, because it delves into one of the possible task-based implementation variables and thus

  6. A Project to Develop Performance Based Instruction through Task Analysis and In-Service Programs. Final Report.

    ERIC Educational Resources Information Center

    Ledoux, Clarence E.

    The primary purposes of this project were to develop catalogs of performance objectives and performance guides based upon validated tasks performed by incumbent workers and to disseminate and diffuse catalogs through inservice activities. The five catalogs developed were based upon tasks performed in the occupations of banking clerk, diesel…

  7. Evaluation of various mental task combinations for near-infrared spectroscopy-based brain-computer interfaces

    NASA Astrophysics Data System (ADS)

    Hwang, Han-Jeong; Lim, Jeong-Hwan; Kim, Do-Won; Im, Chang-Hwan

    2014-07-01

    A number of recent studies have demonstrated that near-infrared spectroscopy (NIRS) is a promising neuroimaging modality for brain-computer interfaces (BCIs). So far, most NIRS-based BCI studies have focused on enhancing the accuracy of the classification of different mental tasks. In the present study, we evaluated the performances of a variety of mental task combinations in order to determine the mental task pairs that are best suited for customized NIRS-based BCIs. To this end, we recorded event-related hemodynamic responses while seven participants performed eight different mental tasks. Classification accuracies were then estimated for all possible pairs of the eight mental tasks (C=28). Based on this analysis, mental task combinations with relatively high classification accuracies frequently included the following three mental tasks: "mental multiplication," "mental rotation," and "right-hand motor imagery." Specifically, mental task combinations consisting of two of these three mental tasks showed the highest mean classification accuracies. It is expected that our results will be a useful reference to reduce the time needed for preliminary tests when discovering individual-specific mental task combinations.

  8. A novel task-oriented optimal design for P300-based brain-computer interfaces

    NASA Astrophysics Data System (ADS)

    Zhou, Zongtan; Yin, Erwei; Liu, Yang; Jiang, Jun; Hu, Dewen

    2014-10-01

    Objective. The number of items of a P300-based brain-computer interface (BCI) should be adjustable in accordance with the requirements of the specific tasks. To address this issue, we propose a novel task-oriented optimal approach aimed at increasing the performance of general P300 BCIs with different numbers of items. Approach. First, we proposed a stimulus presentation with variable dimensions (VD) paradigm as a generalization of the conventional single-character (SC) and row-column (RC) stimulus paradigms. Furthermore, an embedding design approach was employed for any given number of items. Finally, based on the score-P model of each subject, the VD flash pattern was selected by a linear interpolation approach for a certain task. Main results. The results indicate that the optimal BCI design consistently outperforms the conventional approaches, i.e., the SC and RC paradigms. Specifically, there is significant improvement in the practical information transfer rate for a large number of items. Significance. The results suggest that the proposed optimal approach would provide useful guidance in the practical design of general P300-based BCIs.

  9. Acute Exposure to Stress Improves Performance in Trace Eyeblink Conditioning and Spatial Learning Tasks in Healthy Men

    ERIC Educational Resources Information Center

    Duncko, Roman; Cornwell, Brian; Cui, Lihong; Merikangas, Kathleen R.; Grillon, Christian

    2007-01-01

    The present study investigated the effects of acute stress exposure on learning performance in humans using analogs of two paradigms frequently used in animals. Healthy male participants were exposed to the cold pressor test (CPT) procedure, i.e., insertion of the dominant hand into ice water for 60 sec. Following the CPT or the control procedure,…

  10. Evaluation of noise pollution level based upon community exposure and response data

    NASA Technical Reports Server (NTRS)

    Edmiston, R. D.

    1972-01-01

    The results and procedures are reported from an evaluation of noise pollution level as a predictor of annoyance, based on aircraft noise exposure and community response data. The measures of noise exposure presented include composite noise rating, noise exposure forecast, noise and number index. A proposed measure as a universal noise exposure measure for noise pollution level (L sub NP) is discussed.

  11. Suggestion does not de-automatize word reading: evidence from the semantically based Stroop task.

    PubMed

    Augustinova, Maria; Ferrand, Ludovic

    2012-06-01

    Recent studies have shown that the suggestion for participants to construe words as meaningless symbols reduces, or even eliminates, standard Stroop interference in highly suggestible individuals (Raz, Fan, & Posner, 2005; Raz, Kirsch, Pollard, & Nitkin-Kaner, 2006). In these studies, the researchers consequently concluded that this suggestion de-automatizes word reading. The aim of the present study was to closely examine this claim. To this end, highly suggestible individuals completed both standard and semantically based Stroop tasks, either with or without a suggestion to construe the words as meaningless symbols (manipulated in both a between-participants [Exp. 1] and a within-participants [Exp. 2] design). By showing that suggestion substantially reduced standard Stroop interference, these two experiments replicated Raz et al.'s (2006) results. However, in both experiments we also found significant semantically based Stroop effects of similar magnitudes in all suggestion conditions. Taken together, these results indicate that the suggestion to construe words as meaningless symbols does not eliminate, or even reduce, semantic activation (assessed by the semantically based Stroop effect) in highly suggestible individuals, and that such an intervention most likely reduces nonsemantic task-relevant response competition related to the standard Stroop task. In sum, contrary to Raz et al.'s claim, suggestion does not de-automatize or prevent reading (as shown by a significant amount of semantic processing), but rather seems to influence response competition. These results also add to the growing body of evidence showing that semantic activation in the Stroop task is indeed automatic. PMID:22258821

  12. Simultaneous Computation of Two Independent Tasks Using Reservoir Computing Based on a Single Photonic Nonlinear Node With Optical Feedback.

    PubMed

    Nguimdo, Romain Modeste; Verschaffelt, Guy; Danckaert, Jan; Van der Sande, Guy

    2015-12-01

    In this brief, we numerically demonstrate a photonic delay-based reservoir computing system, which processes, in parallel, two independent computational tasks even when the two tasks have unrelated input streams. Our approach is based on a single-longitudinal mode semiconductor ring laser (SRL) with optical feedback. The SRL emits in two directional optical modes. Each directional mode processes one individual task to mitigate possible crosstalk. We illustrate the feasibility of our scheme by analyzing the performance on two benchmark tasks: 1) chaotic time series prediction and 2) nonlinear channel equalization. We identify some feedback configurations for which the results for simultaneous prediction/classification indicate a good performance, but with slight degradation (as compared with the performance obtained for single task processing) due to nonlinear and linear interactions between the two directional modes of the laser. In these configurations, the system performs well on both tasks for a broad range of the parameters. PMID:25751880

  13. Patient-based radiographic exposure factor selection: a systematic review

    SciTech Connect

    Ching, William; Robinson, John; McEntee, Mark

    2014-09-15

    Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system.

  14. Elementary Students' Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks

    NASA Astrophysics Data System (ADS)

    Wendell, Kristen Bethke; Lee, Hee-Sun

    2010-12-01

    Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering design-based science instruction with the goal of constructing a stable, quiet, thermally comfortable model house. The learning outcome of materials science practices was assessed by clinical interviews conducted before and after the instruction, and the learning process was assessed by students' workbooks completed during the instruction. The interviews included two materials selection tasks for designing a sturdy stepstool and an insulated pet habitat. Results indicate that: (1) students significantly improved on both materials selection tasks, (2) their gains were significantly positively associated with the degree of completion of their workbooks, and (3) students who were highly engaged with the workbook's reflective record-keeping tasks showed the greatest improvement on the interviews. These findings suggest the important role workbooks can play in facilitating elementary students' learning of science through authentic activity such as engineering design.

  15. Exploring Fine-Grained Task-based Execution on Multi-GPU Systems

    SciTech Connect

    Chen, Long; Villa, Oreste; Gao, Guang R.

    2011-09-25

    Many-core Graphics Processing Units (GPUs) have been utilized as the computation engine in many scientific fields due to the high peak performance, cost effectiveness, and the availability of user friendly programming environments, e.g., NVIDIA CUDA. However, the conventional data parallel GPU programming paradigm cannot satisfactorily address issues such as load balancing and GPU resource utilization due to the irregular and unbalanced workload patterns exhibited in some applications. In this paper, we explore the design space of task-based solutions for multi-GPU systems. By employing finer-grained tasks than what is supported in the current CUDA, and allowing task sharing, our solutions enable dynamic load balancing. We evaluate our solutions with a Molecular Dynamics application with different atom distributions (from uniform distribution to highly non-uniform distribution). Experimental results obtained on a 4-GPU system show that, for non-uniform distributed systems, our solutions achieve excellent speedup, and significant performance improvement over other solutions based on the standard CUDA APIs.

  16. Feasibility of performing space surveillance tasks with a proposed space-based optical architecture

    NASA Astrophysics Data System (ADS)

    Flohrer, T.; Krag, H.; Klinkrad, H.; Schildknecht, T.

    2011-03-01

    Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO study was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive optical instrument. The SBO instrument was requested to provide statistical information on the space debris population in terms of number of objects and size distribution. The SBO instrument was considered to be a cost-efficient with 20 cm aperture and 6 field-of-view and having flexible integration requirements. It should be possible to integrate the SBO instrument easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are studied for the build-up and maintenance of a catalogue of objects. In this paper we analyse how the proposed SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of objects at higher altitude, and select an orbit close to the terminator plane. A pointing of the sensor orthogonal to the orbital plane with optimal elevation slightly in positive direction (0 and +5) is found optimal for accessing the entire GEO regime within one day, implying a very good coverage of controlled objects in GEO, too. Simulations using ESAs Program for Radar and Optical Observation Forecasting (PROOF) in the version 2005 and a GEO reference population extracted from DISCOS revealed that the proposed pointing scenario provides low phase angles together with low angular velocities of the objects crossing the field-of-view. Radiometric simulations show that the optimal exposure time is 1-2 s, and that spherical objects in GEO with a diameter of below 1 m can be detected. The GEO population can be covered under proper illumination nearly completely, but seasonal drops of the coverage are possible. Subsequent observations of objects are on average at least every 1.5 days, not exceeding 3 days at maximum. A single observation arc spans 3 to 5 on average. Using a simulation environment that connects PROOF to AIUBs program system CelMech we verify the consistency of the initial orbit determination for five selected test objects on subsequent days as a function of realistic astrometric noise levels. The initial orbit determination is possible. We define requirements for a correlator process essential for catalogue build-up and maintenance. Each single observation should provide an astrometric accuracy of at least 1-1.5 so that the initially determined orbits are consistent within a few hundred kilometres for the semi-major axis, 0.01 for the eccentricity, and 0.1 for the inclination.

  17. Autonomy, competence, and social relatedness in task interest within project-based education.

    PubMed

    Minnaert, Alexander; Boekaerts, Monique; de Brabander, Cornelis

    2007-10-01

    To prepare students for instructive collaboration, it is necessary to have insight into students' psychological needs and interest development. The framework of self-determination theory was used to conduct a field experiment involving 114 students in vocational education. These students followed a practical business course which required they work in small learning groups. During the course, students were asked to complete the Quality of Working in Groups Instrument, an online measure of how strong autonomy, competence, social relatedness, and task interest are fulfilled. SEM showed that students' psychological needs were jointly and uniquely related to task interest over time. The significance of this on-line test for the assessment of interest within project-based education is discussed. PMID:18175501

  18. Structural foundations of resting-state and task-based functional connectivity in the human brain.

    PubMed

    Hermundstad, Ann M; Bassett, Danielle S; Brown, Kevin S; Aminoff, Elissa M; Clewett, David; Freeman, Scott; Frithsen, Amy; Johnson, Arianne; Tipper, Christine M; Miller, Michael B; Grafton, Scott T; Carlson, Jean M

    2013-04-01

    Magnetic resonance imaging enables the noninvasive mapping of both anatomical white matter connectivity and dynamic patterns of neural activity in the human brain. We examine the relationship between the structural properties of white matter streamlines (structural connectivity) and the functional properties of correlations in neural activity (functional connectivity) within 84 healthy human subjects both at rest and during the performance of attention- and memory-demanding tasks. We show that structural properties, including the length, number, and spatial location of white matter streamlines, are indicative of and can be inferred from the strength of resting-state and task-based functional correlations between brain regions. These results, which are both representative of the entire set of subjects and consistently observed within individual subjects, uncover robust links between structural and functional connectivity in the human brain. PMID:23530246

  19. Utilization Assessment of Target Electrification Vehicles at Marine Corps Base Camp Lejeune. Task 3

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense base studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 consisted of a survey of the non-tactical fleet of vehicles at MCBCL to begin the review of vehicle mission assignments and types of vehicles in service. Task 2 involved identifying daily operational characteristics of select vehicles and initiating data logging of vehicle movements in order to characterize the vehicle’s mission. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption and whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provide observations related to placement of PEV charging infrastructure. This report provides the results of the data analysis and observations related to replacement of current vehicles with PEVs. This fulfills part of the Task 3 requirements. Task 3 also includes an assessment of the charging infrastructure required to support this replacement, which is the subject of a separate report. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune Fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from MCBCL personnel.

  20. Feature-based attentional modulation increases with stimulus separation in divided-attention tasks.

    PubMed

    Sally, Sharon L; Vidnyánsky, Zoltán; Papathomas, Thomas V

    2009-01-01

    Attention modifies our visual experience by selecting certain aspects of a scene for further processing. It is therefore important to understand factors that govern the deployment of selective attention over the visual field. Both location and feature-specific mechanisms of attention have been identified and their modulatory effects can interact at a neural level (Treue and Martinez-Trujillo, 1999). The effects of spatial parameters on feature-based attentional modulation were examined for the feature dimensions of orientation, motion and color using three divided-attention tasks. Subjects performed concurrent discriminations of two briefly presented targets (Gabor patches) to the left and right of a central fixation point at eccentricities of +/-2.5 degrees , 5 degrees , 10 degrees and 15 degrees in the horizontal plane. Gabors were size-scaled to maintain consistent single-task performance across eccentricities. For all feature dimensions, the data show a linear increase in the attentional effects with target separation. In a control experiment, Gabors were presented on an isoeccentric viewing arc at 10 degrees and 15 degrees at the closest spatial separation (+/-2.5 degrees ) of the main experiment. Under these conditions, the effects of feature-based attentional effects were largely eliminated. Our results are consistent with the hypothesis that feature-based attention prioritizes the processing of attended features. Feature-based attentional mechanisms may have helped direct the attentional focus to the appropriate target locations at greater separations, whereas similar assistance may not have been necessary at closer target spacings. The results of the present study specify conditions under which dual-task performance benefits from sharing similar target features and may therefore help elucidate the processes by which feature-based attention operates. PMID:19891852

  1. Occupational exposure to electric fields and induced currents associated with 400 kV substation tasks from different service platforms.

    PubMed

    Korpinen, Leena H; Elovaara, Jarmo A; Kuisti, Harri A

    2011-01-01

    The aim of the study was to investigate the occupational exposure to electric fields, average current densities, and average total contact currents at 400 kV substation tasks from different service platforms (main transformer inspection, maintenance of operating device of disconnector, maintenance of operating device of circuit breaker). The average values are calculated over measured periods (about 2.5 min). In many work tasks, the maximum electric field strengths exceeded the action values proposed in the EU Directive 2004/40/EC, but the average electric fields (0.2-24.5 kV/m) were at least 40% lower than the maximum values. The average current densities were 0.1-2.3 mA/m² and the average total contact currents 2.0-143.2 µA, that is, clearly less than the limit values of the EU Directive. The average values of the currents in head and contact currents were 16-68% lower than the maximum values when we compared the average value from all cases in the same substation. In the future it is important to pay attention to the fact that the action and limit values of the EU Directive differ significantly. It is also important to take into account that generally, the workers' exposure to the electric fields, current densities, and total contact currents are obviously lower if we use the average values from a certain measured time period (e.g., 2.5 min) than in the case where exposure is defined with only the help of the maximum values. PMID:20925064

  2. Pharmacokinetically based risk assessment of workplace exposure to benzene.

    PubMed

    Beliles, R P; Totman, L C

    1989-04-01

    Cancer risk from exposure to benzene for a working lifetime was estimated from data obtained in studies with rodents. Cancers of the Zymbal gland and the blood-forming system were selected as endpoints for the assessment because of their consistent occurrence. The combined metabolites were judged from toxicological data to be the best representative of the reactive agent. Because of similarity in the percentages of lifetime exposed in the rodent studies and in the occupational setting, the amount metabolized/day as a result of exposures 5 days a week for a lifetime was judged to be an appropriate dose paradigm for this assessment. Derived Michaelis-Menton constants were used to convert the doses of combined metabolites from the pharmacokinetic studies to the doses used in the bioassays. Scaling across species was based on allometric relationships. Experimental data were used to scale doses across species with body weight ratios raised to the exponents of 0.74 for the inhalation route and 1.0 for the oral route. The occupational lifetime cancer risk estimated from rodent data was 6 to 14 cases/1000 workers, which is consistent with the 9.5 to 174 leukemia cases/1000 estimated by others from epidemiological data. Implications of these estimates and uncertainties associated with making them are discussed. PMID:2655040

  3. Exposure to smoking cues during an emotion recognition task can modulate limbic fMRI activation in cigarette smokers.

    PubMed

    Artiges, Eric; Ricalens, Emmanuel; Berthoz, Sylvie; Krebs, Marie-Odile; Penttilä, Jani; Trichard, Christian; Martinot, Jean-Luc

    2009-09-01

    Smoking cues (SCs) refer to smoking-associated environmental stimuli that may trigger craving and withdrawal symptoms, and predispose to relapse in smokers. Although previous brain imaging studies have explored neural responses to SCs, no study has characterized the effects of SCs on cerebral activity in smokers engaged in an attention-demanding cognitive task that is unrelated to smoking. Thirteen tobacco smokers and a demographically matched group of 13 healthy non-smokers participated in a fast event-related functional magnetic resonance imaging (fMRI) study that involved a visual task integrating SCs and neutral cues (NCs) during emotion recognition trials requiring a high level of attention. No significant SC-induced alterations were detected in smokers' behavioural performance. fMRI results show that non-smokers exhibited no difference between SC and NC trials; in contrast, smokers showed SC-induced widespread deactivations in a limbic, paralimbic and striatal network classically involved in addiction, and activation in the right dorsolateral prefrontal cortex. In addition, a correlation between deactivation of the right insula and the severity of smoking dependence (Fagerström test) was detected in smokers. These results suggest that the neural reactivity of smokers to SCs can be modified in the context of a cognitive challenge. This could reflect smokers' ability to inhibit cue-induced craving and may help in smoking cessation. PMID:19650816

  4. Effects of occupational exposure - is there a link between exposure based on an occupational questionnaire and semen quality?

    PubMed

    Jurewicz, Joanna; Radwan, Michał; Sobala, Wojciech; Radwan, Paweł; Bochenek, Michał; Hanke, Wojciech

    2014-08-01

    Several studies have suggested that human semen quality has declined over past decades and some have associated decline with occupational exposures. Many studies have been conducted in occupational settings, where exposure to occupational pollutants is intense. Our objective was to examine the association between exposure to occupational factors based on an occupational exposure questionnaire, and semen quality parameters (sperm concentration, motility, sperm morphology) and sperm chromatin structure. The study population consisted of 336 men who were attending an infertility clinic for diagnostic purposes and who had a normal semen concentration of ≥15 mln/ml according to WHO criteria. All participants were interviewed and provided a semen sample. Additionally, a detailed questionnaire about the exposure to occupational factors was performed among the study participants. The results of the study suggest that occupational factors may affect semen quality. The exposure to noise during work was associated with decreased motility and increased DNA damage (p = 0.005 and p = 0.02, respectively). Exposure to polyvinyl chloride (PVC) decreased sperm concentration and motility (p = 0.02 and p = 0.03, respectively). Whereas exposure to high temperatures and sitting for more than 6 hours during work was positively associated with DNA fragmentation index (DFI) (p = 0.03 and p = 0.001, respectively). After applying the correction for multiple comparisons only the exposure to noise and sitting ≥6 hours during work was associated with poorer semen quality (decreased motility and increased DFI, respectively). This study showed associations between self-reported occupational exposures and impaired semen parameters. The occupational exposure questionnaire may be useful in clinical practice for patients and physicians to identify the work factors associated with poorer semen quality. PMID:24702586

  5. [Exposure to vegetal esters based metal cutting fluids: health effects].

    PubMed

    Riva, M M; Bellini, M; Leghissa, P; Gambini, D; Mosconi, G

    2012-01-01

    The aim of our research is to study respiratory and dermatologic diseases (irritative and allergic) in a cohort of workers exposed to vegetal esters based metal cutting fluids of the latest generation. A cohort of 81 workers (mean age 34.5 years, seniority 17.4 years), with mean exposure to vegetal esters based metal cutting fluids of 2.8 years, has been subjected to clinical evaluations. The investigation did not reveal any disease or disorder of the respiratory system, any folluculitis or any allergic contact dermatitis caused by sensitization to vegetal esters based metal cutting fluids. On the contrary we documented 5 cases of irritant contact dermatitis, even if favored by an improper use of protection devices. According to early results, the introduction of vegetal esters based metal cutting fluids seems to reduce the risk to the worker's health. A longitudinal surveillance is still needed to confirm that even in the medium and long-term sensitizations will not occur. PMID:23405602

  6. Task-based modeling and optimization of a cone-beam CT scanner for musculoskeletal imaging

    PubMed Central

    Prakash, P.; Zbijewski, W.; Gang, G. J.; Ding, Y.; Stayman, J. W.; Yorkston, J.; Carrino, J. A.; Siewerdsen, J. H.

    2011-01-01

    Purpose: This work applies a cascaded systems model for cone-beam CT imaging performance to the design and optimization of a system for musculoskeletal extremity imaging. The model provides a quantitative guide to the selection of system geometry, source and detector components, acquisition techniques, and reconstruction parameters. Methods: The model is based on cascaded systems analysis of the 3D noise-power spectrum (NPS) and noise-equivalent quanta (NEQ) combined with factors of system geometry (magnification, focal spot size, and scatter-to-primary ratio) and anatomical background clutter. The model was extended to task-based analysis of detectability index (d′) for tasks ranging in contrast and frequency content, and d′ was computed as a function of system magnification, detector pixel size, focal spot size, kVp, dose, electronic noise, voxel size, and reconstruction filter to examine trade-offs and optima among such factors in multivariate analysis. The model was tested quantitatively versus the measured NPS and qualitatively in cadaver images as a function of kVp, dose, pixel size, and reconstruction filter under conditions corresponding to the proposed scanner. Results: The analysis quantified trade-offs among factors of spatial resolution, noise, and dose. System magnification (M) was a critical design parameter with strong effect on spatial resolution, dose, and x-ray scatter, and a fairly robust optimum was identified at M ∼ 1.3 for the imaging tasks considered. The results suggested kVp selection in the range of ∼65–90 kVp, the lower end (65 kVp) maximizing subject contrast and the upper end maximizing NEQ (90 kVp). The analysis quantified fairly intuitive results—e.g., ∼0.1–0.2 mm pixel size (and a sharp reconstruction filter) optimal for high-frequency tasks (bone detail) compared to ∼0.4 mm pixel size (and a smooth reconstruction filter) for low-frequency (soft-tissue) tasks. This result suggests a specific protocol for 1 × 1 (full-resolution) projection data acquisition followed by full-resolution reconstruction with a sharp filter for high-frequency tasks along with 2 × 2 binning reconstruction with a smooth filter for low-frequency tasks. The analysis guided selection of specific source and detector components implemented on the proposed scanner. The analysis also quantified the potential benefits and points of diminishing return in focal spot size, reduced electronic noise, finer detector pixels, and low-dose limits of detectability. Theoretical results agreed quantitatively with the measured NPS and qualitatively with evaluation of cadaver images by a musculoskeletal radiologist. Conclusions: A fairly comprehensive model for 3D imaging performance in cone-beam CT combines factors of quantum noise, system geometry, anatomical background, and imaging task. The analysis provided a valuable, quantitative guide to design, optimization, and technique selection for a musculoskeletal extremities imaging system under development. PMID:21992379

  7. Task-based modeling and optimization of a cone-beam CT scanner for musculoskeletal imaging

    SciTech Connect

    Prakash, P.; Zbijewski, W.; Gang, G. J.; Ding, Y.; Stayman, J. W.; Yorkston, J.; Carrino, J. A.; Siewerdsen, J. H.

    2011-10-15

    Purpose: This work applies a cascaded systems model for cone-beam CT imaging performance to the design and optimization of a system for musculoskeletal extremity imaging. The model provides a quantitative guide to the selection of system geometry, source and detector components, acquisition techniques, and reconstruction parameters. Methods: The model is based on cascaded systems analysis of the 3D noise-power spectrum (NPS) and noise-equivalent quanta (NEQ) combined with factors of system geometry (magnification, focal spot size, and scatter-to-primary ratio) and anatomical background clutter. The model was extended to task-based analysis of detectability index (d') for tasks ranging in contrast and frequency content, and d' was computed as a function of system magnification, detector pixel size, focal spot size, kVp, dose, electronic noise, voxel size, and reconstruction filter to examine trade-offs and optima among such factors in multivariate analysis. The model was tested quantitatively versus the measured NPS and qualitatively in cadaver images as a function of kVp, dose, pixel size, and reconstruction filter under conditions corresponding to the proposed scanner. Results: The analysis quantified trade-offs among factors of spatial resolution, noise, and dose. System magnification (M) was a critical design parameter with strong effect on spatial resolution, dose, and x-ray scatter, and a fairly robust optimum was identified at M {approx} 1.3 for the imaging tasks considered. The results suggested kVp selection in the range of {approx}65-90 kVp, the lower end (65 kVp) maximizing subject contrast and the upper end maximizing NEQ (90 kVp). The analysis quantified fairly intuitive results--e.g., {approx}0.1-0.2 mm pixel size (and a sharp reconstruction filter) optimal for high-frequency tasks (bone detail) compared to {approx}0.4 mm pixel size (and a smooth reconstruction filter) for low-frequency (soft-tissue) tasks. This result suggests a specific protocol for 1 x 1 (full-resolution) projection data acquisition followed by full-resolution reconstruction with a sharp filter for high-frequency tasks along with 2 x 2 binning reconstruction with a smooth filter for low-frequency tasks. The analysis guided selection of specific source and detector components implemented on the proposed scanner. The analysis also quantified the potential benefits and points of diminishing return in focal spot size, reduced electronic noise, finer detector pixels, and low-dose limits of detectability. Theoretical results agreed quantitatively with the measured NPS and qualitatively with evaluation of cadaver images by a musculoskeletal radiologist. Conclusions: A fairly comprehensive model for 3D imaging performance in cone-beam CT combines factors of quantum noise, system geometry, anatomical background, and imaging task. The analysis provided a valuable, quantitative guide to design, optimization, and technique selection for a musculoskeletal extremities imaging system under development.

  8. The Cruelest Cure? Ethical Issues in the Implementation of Exposure-Based Treatments

    ERIC Educational Resources Information Center

    Olatunji, Bunmi O.; Deacon, Brett J.; Abramowitz, Jonathan S.

    2009-01-01

    Numerous studies have provided supportive evidence for the efficacy of exposure-based treatments for many psychological disorders. However, surprisingly few therapists use exposure therapy in the clinical setting. Although the limited use of exposure-based treatments may be partially attributable to a shortage of suitably trained therapists,…

  9. Simulation-based flexible ureteroscopy training using a novel ureteroscopy part-task trainer

    PubMed Central

    Blankstein, Udi; Lantz, Andrea G.; D’A Honey, R. John; Pace, Kenneth T.; Ordon, Michael; Lee, Jason Young

    2015-01-01

    Introduction: Simulation-based training (SBT) is being increasingly used for novice trainees as a means of overcoming the early learning curve associated with new surgical skills. We designed a SBT flexible ureteroscopy (fURS) course using a novel inanimate training model (Cook Medical, Bloomington, IN; URS model). We evaluated the course and validated this Cook URS model. Methods: A 2-week SBT fURS course was designed for junior level urology trainees at 2 Canadian universities. The curriculum included didactic lectures, hands-on training, independent training sessions with expert feedback, and use of the Cook URS part-task model. Baseline and post-course assessments of trainee fURS skills were conducted using a standardized test task (fURS with basket manipulation of a calyceal stone). Performances were video-recorded and reviewed by 2 blinded experts using a validated assessment device. Results: Fifteen residents (postgraduate years [PGY] 0–3) participated in the course. Of the participants, 80% rated the Cook URS model as realistic (mean = 4.2/5) and 5 endourology experts rated it as useful as a training device (mean = 4.9/5), providing both face and content validity. The mean overall performance scores, task completion times, and passing ratings correlated with trainee clinical fURS experience – demonstrating construct validity for the Cook URS model. The mean post-course task completion times (15.76 vs. 9.37 minutes, p = 0.001) and overall performance scores (19.20 vs. 25.25, p = 0.007) were significantly better than at baseline. Post-course performance was better in all domains assessed by the validated assessment device. Conclusions: This study demonstrates that a SBT curriculum for fURS can lead to improved short-term technical skills among junior level urology residents. The Cook URS model demonstrated good face, content and construct validity. PMID:26644806

  10. Web-Based Undergraduate Chemistry Problem-Solving: The Interplay of Task Performance, Domain Knowledge and Web-Searching Strategies

    ERIC Educational Resources Information Center

    She, Hsiao-Ching; Cheng, Meng-Tzu; Li, Ta-Wei; Wang, Chia-Yu; Chiu, Hsin-Tien; Lee, Pei-Zon; Chou, Wen-Chi; Chuang, Ming-Hua

    2012-01-01

    This study investigates the effect of Web-based Chemistry Problem-Solving, with the attributes of Web-searching and problem-solving scaffolds, on undergraduate students' problem-solving task performance. In addition, the nature and extent of Web-searching strategies students used and its correlation with task performance and domain knowledge also…

  11. An Online Task-Based Language Learning Environment: Is It Better for Advanced- or Intermediate-Level Second Language Learners?

    ERIC Educational Resources Information Center

    Arslanyilmaz, Abdurrahman

    2012-01-01

    This study investigates the relationship of language proficiency to language production and negotiation of meaning that non-native speakers (NNSs) produced in an online task-based language learning (TBLL) environment. Fourteen NNS-NNS dyads collaboratively completed four communicative tasks, using an online TBLL environment specifically designed…

  12. Complexity Measures, Task Type, and Analytic Evaluations of Speaking Proficiency in a School-Based Assessment Context

    ERIC Educational Resources Information Center

    Gan, Zhengdong

    2012-01-01

    This study, which is part of a large-scale study of using objective measures to validate assessment rating scales and assessment tasks in a high-profile school-based assessment initiative in Hong Kong, examined how grammatical complexity measures relate to task type and analytic evaluations of students' speaking proficiency in a classroom-based…

  13. A Tentative Study on the Task-Based Teaching of Writing to English Majors in Chinese Settings

    ERIC Educational Resources Information Center

    Zhaochun, Sun

    2015-01-01

    Under task-based learning (TBL) framework, language learners engage in purposeful, problem-oriented, and outcome-driven tasks that are comparable to traditional teaching methods which focus only on the correctness of grammar. In this study, the author employs Jane Willis' TBL framework and examines its effects on the improvement of EFL learners'…

  14. Web-Based Undergraduate Chemistry Problem-Solving: The Interplay of Task Performance, Domain Knowledge and Web-Searching Strategies

    ERIC Educational Resources Information Center

    She, Hsiao-Ching; Cheng, Meng-Tzu; Li, Ta-Wei; Wang, Chia-Yu; Chiu, Hsin-Tien; Lee, Pei-Zon; Chou, Wen-Chi; Chuang, Ming-Hua

    2012-01-01

    This study investigates the effect of Web-based Chemistry Problem-Solving, with the attributes of Web-searching and problem-solving scaffolds, on undergraduate students' problem-solving task performance. In addition, the nature and extent of Web-searching strategies students used and its correlation with task performance and domain knowledge also

  15. Creating Task-Centered Instruction for Web-Based Instruction: Obstacles and Solutions

    ERIC Educational Resources Information Center

    Gardner, Joel; Jeon, Tae

    2010-01-01

    Merrill proposes First Principles of Instruction, including a problem- or task-centered strategy for designing instruction. However, when the tasks or problems are ill-defined or complex, task-centered instruction can be difficult to design. We describe an online task-centered training at a land-grant university designed to train employees to use…

  16. Creating Task-Centered Instruction for Web-Based Instruction: Obstacles and Solutions

    ERIC Educational Resources Information Center

    Gardner, Joel; Jeon, Tae

    2010-01-01

    Merrill proposes First Principles of Instruction, including a problem- or task-centered strategy for designing instruction. However, when the tasks or problems are ill-defined or complex, task-centered instruction can be difficult to design. We describe an online task-centered training at a land-grant university designed to train employees to use

  17. Endocrine and immunological parameters in individuals involved in Prestige spill cleanup tasks seven years after the exposure.

    PubMed

    Laffon, Blanca; Aguilera, Francisco; Ríos-Vázquez, Julia; García-Lestón, Julia; Fuchs, Dietmar; Valdiglesias, Vanessa; Pásaro, Eduardo

    2013-09-01

    In November 2002 the oil tanker Prestige spilled 63,000tonnes of heavy oil off the northwest coast of Spain, impacting more than 1000km of coastline. A general concern led to a huge mobilization of human and technical resources, and more than 300,000 people participated in cleanup activities, which lasted up to 10months. Some endocrine and immunological alterations were reported in Prestige oil exposed subjects for several months. Therefore, the objective of this study was to evaluate if these alterations are still present seven years after the exposure. Fifty-four individuals exposed for at least 2months were compared to 50 matched referents. Prolactin and cortisol plasma concentrations, percentages of lymphocyte subsets (CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+)16(+)), plasma levels of circulating cytokines (interleukin (IL) 2, IL4, IL6, IL10, tumour necrosis factor α, and interferon γ), and serum concentrations of neopterin, tryptophan and kynurenine were determined in peripheral blood samples. Results showed significant differences in exposed individuals vs. referents only in cortisol (increase), kynurenine and %CD16(+)56(+) lymphocytes (both decrease). Time of exposure to the oil or using protective clothes did not influence the results, but effect of using protective mask was observed on neopterin, %CD8(+), CD4(+)/CD8(+) ratio and IL4. Surveillance of the exposed individuals for early detection of possible health problems related to the endocrine or immunological systems is recommended. PMID:23792419

  18. Implementation Approach for Electric Vehicles at Marine Corps Base Camp Lejeune. Task 4

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense base studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). This study is focused on the Marine Corps Base Camp Lejeune (MCBCL) located in North Carolina. Task 1 consisted of a survey of the non-tactical fleet of vehicles at MCBCL to begin the review of vehicle mission assignments and types of vehicles in service. In Task 2, daily operational characteristics of vehicles were identified to select vehicles for further monitoring and attachment of data loggers. Task 3 recorded vehicle movements in order to characterize the vehicles’ missions. The results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption, i.e., whether a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV) (collectively PEVs) can fulfill the mission requirements. It also provided the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the MCBCL fleet. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from MCBCL personnel.

  19. Patient-based radiographic exposure factor selection: a systematic review

    PubMed Central

    Ching, William; Robinson, John; McEntee, Mark

    2014-01-01

    Introduction Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Methods Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. Results The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Conclusion Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system. PMID:26229654

  20. A graphical workstation based part-task flight simulator for preliminary rapid evaluation of advanced displays

    NASA Technical Reports Server (NTRS)

    Wanke, Craig; Kuchar, James; Hahn, Edward; Pritchett, A.; Hansman, R. John

    1994-01-01

    Advances in avionics and display technology are significantly changing the cockpit environment in current transport aircraft. The MIT Aeronautical Systems Lab (ASL) developed a part-task flight simulator specifically to study the effects of these new technologies on flight crew situational awareness and performance. The simulator is based on a commercially-available graphics workstation, and can be rapidly reconfigured to meet the varying demands of experimental studies. The simulator was successfully used to evaluate graphical microbursts alerting displays, electronic instrument approach plates, terrain awareness and alerting displays, and ATC routing amendment delivery through digital datalinks.

  1. A graphical workstation based part-task flight simulator for preliminary rapid evaluation of advanced displays

    NASA Technical Reports Server (NTRS)

    Wanke, Craig; Kuchar, James; Hahn, Edward; Pritchett, Amy; Hansman, R. J.

    1992-01-01

    Advances in avionics and display technology are significantly changing the cockpit environment in current transport aircraft. The MIT Aeronautical Systems Lab (ASL) has developed a part-task flight simulator specifically to study the effects of these new technologies on flight crew situational awareness and performance. The simulator is based on a commercially-available graphics workstation, and can be rapidly reconfigured to meet the varying demands of experimental studies. The simulator has been successfully used to evaluate graphical microburst alerting displays, electronic instrument approach plates, terrain awareness and alerting displays, and ATC routing amendment delivery through digital datalinks.

  2. Sun exposure and malignant lymphoma: a population-based case-control study in Germany.

    PubMed

    Weihkopf, Thomas; Becker, Nikolaus; Nieters, Alexandra; Mester, Birte; Deeg, Evelin; Elsner, Gine; Blettner, Maria; Seidler, Andreas

    2007-06-01

    Although some causes for malignant lymphoma are known their etiology is not well understood so far. We analyze the relationship between sun exposure and malignant lymphoma in a multicenter, population-based case-control study. Patients with malignant lymphoma (n = 710, 18-80 years) were prospectively recruited in 6 study regions in Germany. For each case, a gender, region and age-matched control was drawn from population-registers. In personal interviews, lifetime holidays spent in sunny climate, outdoor leisure activities and sunbed or sunlamp use were recorded. On basis of job task-specific supplementary questionnaires, an occupational physician assessed the cumulative working time outside. Odds ratios (OR) and 95%-confidence-intervals (CI) were calculated using conditional logistic regression analysis, adjusted for smoking and alcohol consumption. To increase statistical power, patients with specific lymphoma subentities were additionally compared with the entire control group using unconditional logistic regression. We observed a reduced overall lymphoma risk among subjects having spent vacations at sunny climates or frequently used sunbeds or sunlamps. The analysis of lymphoma subentities revealed similar results with the exception of T-NHL and follicular lymphoma which were positively associated with outdoor leisure activities. While cumulative working time outside appeared unrelated to NHL overall and most subentities, it was negatively associated with follicular lymphoma and weakly positively to HL. This data suggest that exposure to natural and artificial ultraviolet radiation may reduce the OR for lymphoma in this study population. PMID:17311289

  3. When you smile, you become happy: evidence from resting state task-based fMRI.

    PubMed

    Chang, Jingjing; Zhang, Meng; Hitchman, Glenn; Qiu, Jiang; Liu, Yijun

    2014-12-01

    Simulation studies on emotion have shown that facial actions can initiate and modulate particular emotions. However, the neural mechanisms of these initiating and modulating functions are unclear. In this study, we used resting-state functional magnetic resonance imaging (fMRI) and task-based fMRI to explore these processes by examining spontaneous cerebral activities and brain activations under two conditions: holding a pen using only the teeth (HPT: facilitating the muscles typically associated with smiling) and holding a pen using only the lips (HPL: inhibiting the muscles typically associated with smiling). The resting-state fMRI results showed that compared with the HPL condition, significant increases in the amplitudes of low-frequency fluctuations were found in the right posterior cingulate gyrus [PCG; Brodmann area 31 (BA31)] and in the left middle frontal gyrus (MFG; BA9) in the HPT condition. These findings might be related to the initiation of positive emotions (PCG) and to the control and allocation of attention (MFG). The task-based fMRI results showed that the inferior parietal lobule, left supplementary motor area, superior parietal lobule, precuneus, and bilateral middle cingulum were active when facial manipulation influenced the recognition of emotional facial expressions. These results demonstrate that facial actions might not only initiate a particular emotion and draw attention, but also influence face-based emotion recognition. PMID:25139308

  4. Proportional reasoning as a heuristic-based process: time constraint and dual task considerations.

    PubMed

    Gillard, Ellen; Van Dooren, Wim; Schaeken, Walter; Verschaffel, Lieven

    2009-01-01

    The present study interprets the overuse of proportional solution methods from a dual process framework. Dual process theories claim that analytic operations involve time-consuming executive processing, whereas heuristic operations are fast and automatic. In two experiments to test whether proportional reasoning is heuristic-based, the participants solved "proportional" problems, for which proportional solution methods provide correct answers, and "nonproportional" problems known to elicit incorrect answers based on the assumption of proportionality. In Experiment 1, the available solution time was restricted. In Experiment 2, the executive resources were burdened with a secondary task. Both manipulations induced an increase in proportional answers and a decrease in correct answers to nonproportional problems. These results support the hypothesis that the choice for proportional methods is heuristic-based. PMID:19261584

  5. Extraversion differentiates between model-based and model-free strategies in a reinforcement learning task.

    PubMed

    Skatova, Anya; Chan, Patricia A; Daw, Nathaniel D

    2013-01-01

    Prominent computational models describe a neural mechanism for learning from reward prediction errors, and it has been suggested that variations in this mechanism are reflected in personality factors such as trait extraversion. However, although trait extraversion has been linked to improved reward learning, it is not yet known whether this relationship is selective for the particular computational strategy associated with error-driven learning, known as model-free reinforcement learning, vs. another strategy, model-based learning, which the brain is also known to employ. In the present study we test this relationship by examining whether humans' scores on an extraversion scale predict individual differences in the balance between model-based and model-free learning strategies in a sequentially structured decision task designed to distinguish between them. In previous studies with this task, participants have shown a combination of both types of learning, but with substantial individual variation in the balance between them. In the current study, extraversion predicted worse behavior across both sorts of learning. However, the hypothesis that extraverts would be selectively better at model-free reinforcement learning held up among a subset of the more engaged participants, and overall, higher task engagement was associated with a more selective pattern by which extraversion predicted better model-free learning. The findings indicate a relationship between a broad personality orientation and detailed computational learning mechanisms. Results like those in the present study suggest an intriguing and rich relationship between core neuro-computational mechanisms and broader life orientations and outcomes. PMID:24027514

  6. The effects of exposure to traumatic stressors on inhibitory control in police officers: a dense electrode array study using a Go/NoGo continuous performance task.

    PubMed

    Covey, Thomas J; Shucard, Janet L; Violanti, John M; Lee, Jeff; Shucard, David W

    2013-03-01

    Exposure to psychologically stressful and traumatic experiences and the requirement of heightened attention to environmental stimuli are common in police work. Police officers are at increased risk for stress-related disorders such as Post-Traumatic Stress Disorder (PTSD). Traumatic experiences can result in changes to brain structure and function associated with attention and cognitive control processes (such as response inhibition). Despite the significance that these cognitive functions may have on job performance in police officers, few studies have examined the effects of exposure to traumatic events on top-down cognitive control functions in police. In the present study, a dense electrode array system was used to examined the N2 and P3 components of the event-related potential (ERP) during a Go/NoGo continuous performance task (Go/NoGo CPT) in trauma-exposed police officers who did not meet criteria for a current diagnosis of PTSD and in non-trauma exposed civilian controls. Amplitude and latency were obtained to Go, NoGo, and non-target trials. The major between-group findings were for P3 amplitude. There were no group effects for N2. Both groups had an enhanced fronto-central P3 amplitude to NoGo compared to Go trials. However, police had greater P3 amplitude compared to controls for all trial types (Go, NoGo, non-target). PTSD symptom scores in police officers were positively correlated with fronto-central NoGo P3 amplitude, but not with posterior NoGo amplitude. This study provides evidence of heightened attention and/or arousal in police officers as indicated by the generally greater P3 amplitude in police compared to controls during a task requiring sustained attention and inhibitory control. Greater PTSD symptom severity in trauma-exposed individuals may affect frontal cognitive control systems related to response inhibition. PMID:23528305

  7. A Knowledge-Based Strategy for the Automated Support to Network Management Tasks

    NASA Astrophysics Data System (ADS)

    Abar, Sameera; Kinoshita, Tetsuo

    This paper presents a domain-ontology driven multi-agent based scheme for representing the knowledge of the communication network management system. In the proposed knowledge-intensive framework, the static domain-related concepts are articulated as the domain knowledge ontology. The experiential knowledge for managing the network is represented as the fault-case reasoning models, and it is explicitly encoded as the core knowledge of multi-agent middleware layer as heuristic production-type rules. These task-oriented management expertise manipulates the domain content and structure during the diagnostic sessions. The agents' rules along with the embedded generic java-based problem-solving algorithms and run-time log information, perform the automated management tasks. For the proof of concept, an experimental network system has been implemented in our laboratory, and the deployment of some test-bed scenarios is performed. Experimental results confirm a marked reduction in the management-overhead of the network administrator, as compared to the manual network management techniques, in terms of the time-taken and effort-done during a particular fault-diagnosis session. Validation of the reusability/modifiability aspects of our system, illustrates the flexible manipulation of the knowledge fragments within diverse application contexts. The proposed approach can be regarded as one of the pioneered steps towards representing the network knowledge via reusable domain ontology and intelligent agents for the automated network management support systems.

  8. Prometheus: Scalable and Accurate Emulation of Task-Based Applications on Many-Core Systems.

    SciTech Connect

    Kestor, Gokcen; Gioiosa, Roberto; Chavarría-Miranda, Daniel

    2015-03-01

    Modeling the performance of non-deterministic parallel applications on future many-core systems requires the development of novel simulation and emulation techniques and tools. We present “Prometheus”, a fast, accurate and modular emulation framework for task-based applications. By raising the level of abstraction and focusing on runtime synchronization, Prometheus can accurately predict applications’ performance on very large many-core systems. We validate our emulation framework against two real platforms (AMD Interlagos and Intel MIC) and report error rates generally below 4%. We, then, evaluate Prometheus’ performance and scalability: our results show that Prometheus can emulate a task-based application on a system with 512K cores in 11.5 hours. We present two test cases that show how Prometheus can be used to study the performance and behavior of systems that present some of the characteristics expected from exascale supercomputer nodes, such as active power management and processors with a high number of cores but reduced cache per core.

  9. An integrated utility-based model of conflict evaluation and resolution in the Stroop task.

    PubMed

    Chuderski, Adam; Smolen, Tomasz

    2016-04-01

    Cognitive control allows humans to direct and coordinate their thoughts and actions in a flexible way, in order to reach internal goals regardless of interference and distraction. The hallmark test used to examine cognitive control is the Stroop task, which elicits both the weakly learned but goal-relevant and the strongly learned but goal-irrelevant response tendencies, and requires people to follow the former while ignoring the latter. After reviewing the existing computational models of cognitive control in the Stroop task, its novel, integrated utility-based model is proposed. The model uses 3 crucial control mechanisms: response utility reinforcement learning, utility-based conflict evaluation using the Festinger formula for assessing the conflict level, and top-down adaptation of response utility in service of conflict resolution. Their complex, dynamic interaction led to replication of 18 experimental effects, being the largest data set explained to date by 1 Stroop model. The simulations cover the basic congruency effects (including the response latency distributions), performance dynamics and adaptation (including EEG indices of conflict), as well as the effects resulting from manipulations applied to stimulation and responding, which are yielded by the extant Stroop literature. (PsycINFO Database Record PMID:26751852

  10. Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

    2014-05-01

    Near-infrared spectroscopy (NIRS) is a developing and promising functional brain imaging technology. Developing data analysis methods to effectively extract meaningful information from collected data is the major bottleneck in popularizing this technology. In this study, we measured hemodynamic activity of the prefrontal cortex (PFC) during a color-word matching Stroop task using NIRS. Hemispheric lateralization was examined by employing traditional activation and novel NIRS-based connectivity analyses simultaneously. Wavelet transform coherence was used to assess intrahemispheric functional connectivity. Spearman correlation analysis was used to examine the relationship between behavioral performance and activation/functional connectivity, respectively. In agreement with activation analysis, functional connectivity analysis revealed leftward lateralization for the Stroop effect and correlation with behavioral performance. However, functional connectivity was more sensitive than activation for identifying hemispheric lateralization. Granger causality was used to evaluate the effective connectivity between hemispheres. The results showed increased information flow from the left to the right hemispheres for the incongruent versus the neutral task, indicating a leading role of the left PFC. This study demonstrates that the NIRS-based connectivity can reveal the functional architecture of the brain more comprehensively than traditional activation, helping to better utilize the advantages of NIRS.

  11. Prospective and Retrospective Time Estimates of Children: A Comparison Based on Ecological Tasks

    PubMed Central

    Bisson, Nicolas; Tobin, Simon; Grondin, Simon

    2012-01-01

    Children's time estimation literature lacks of studies comparing prospective and retrospective time estimates of long lasting ecological tasks, i.e. tasks reflecting children's daily activities. In the present study, children were asked to estimate prospectively or retrospectively how much time they played a video game or read a magazine. Regardless of the task, the results revealed that prospective time estimates were longer than the retrospective ones. Also, time estimates of the video game task were longer, less accurate and more variable than those of the reading task. The results are discussed in the light of the current literature about time estimation of long lasting ecological tasks. PMID:22412982

  12. Overlay improvement by exposure map based mask registration optimization

    NASA Astrophysics Data System (ADS)

    Shi, Irene; Guo, Eric; Chen, Ming; Lu, Max; Li, Gordon; Li, Rivan; Tian, Eric

    2015-03-01

    Along with the increased miniaturization of semiconductor electronic devices, the design rules of advanced semiconductor devices shrink dramatically. [1] One of the main challenges of lithography step is the layer-to-layer overlay control. Furthermore, DPT (Double Patterning Technology) has been adapted for the advanced technology node like 28nm and 14nm, corresponding overlay budget becomes even tighter. [2][3] After the in-die mask registration (pattern placement) measurement is introduced, with the model analysis of a KLA SOV (sources of variation) tool, it's observed that registration difference between masks is a significant error source of wafer layer-to-layer overlay at 28nm process. [4][5] Mask registration optimization would highly improve wafer overlay performance accordingly. It was reported that a laser based registration control (RegC) process could be applied after the pattern generation or after pellicle mounting and allowed fine tuning of the mask registration. [6] In this paper we propose a novel method of mask registration correction, which can be applied before mask writing based on mask exposure map, considering the factors of mask chip layout, writing sequence, and pattern density distribution. Our experiment data show if pattern density on the mask keeps at a low level, in-die mask registration residue error in 3sigma could be always under 5nm whatever blank type and related writer POSCOR (position correction) file was applied; it proves random error induced by material or equipment would occupy relatively fixed error budget as an error source of mask registration. On the real production, comparing the mask registration difference through critical production layers, it could be revealed that registration residue error of line space layers with higher pattern density is always much larger than the one of contact hole layers with lower pattern density. Additionally, the mask registration difference between layers with similar pattern density could also achieve under 5nm performance. We assume mask registration excluding random error is mostly induced by charge accumulation during mask writing, which may be calculated from surrounding exposed pattern density. Multi-loading test mask registration result shows that with x direction writing sequence, mask registration behavior in x direction is mainly related to sequence direction, but mask registration in y direction would be highly impacted by pattern density distribution map. It proves part of mask registration error is due to charge issue from nearby environment. If exposure sequence is chip by chip for normal multi chip layout case, mask registration of both x and y direction would be impacted analogously, which has also been proved by real data. Therefore, we try to set up a simple model to predict the mask registration error based on mask exposure map, and correct it with the given POSCOR (position correction) file for advanced mask writing if needed.

  13. Counting-On, Trading and Partitioning: Effects of Training and Prior Knowledge on Performance on Base-10 Tasks

    ERIC Educational Resources Information Center

    Saxton, Matthew; Cakir, Kadir

    2006-01-01

    Factors affecting performance on base-10 tasks were investigated in a series of four studies with a total of 453 children aged 5-7 years. Training in counting-on was found to enhance child performance on base-10 tasks (Studies 2, 3, and 4), while prior knowledge of counting-on (Study 1), trading (Studies 1 and 3), and partitioning (Studies 1 and…

  14. Estimating cognitive workload using wavelet entropy-based features during an arithmetic task.

    PubMed

    Zarjam, Pega; Epps, Julien; Chen, Fang; Lovell, Nigel H

    2013-12-01

    Electroencephalography (EEG) has shown promise as an indicator of cognitive workload; however, precise workload estimation is an ongoing research challenge. In this investigation, seven levels of workload were induced using an arithmetic task, and the entropy of wavelet coefficients extracted from EEG signals is shown to distinguish all seven levels. For a subject-independent multi-channel classification scheme, the entropy features achieved high accuracy, up to 98% for channels from the frontal lobes, in the delta frequency band. This suggests that a smaller number of EEG channels in only one frequency band can be deployed for an effective EEG-based workload classification system. Together with analysis based on phase locking between channels, these results consistently suggest increased synchronization of neural responses for higher load levels. PMID:24290935

  15. Using Agent-Based Approaches to Characterize Exposure Related Behavior

    EPA Science Inventory

    The Tox21 initiative is generating data on biological activity, toxicity, and chemical properties for over 8,000 substances. One of the goals for EPA’s National Exposure Research Lab (NERL) is to assess the magnitude and variability in the public’s exposures to these ...

  16. Population Based Exposure Assessment of Bioaccessible Arsenic in Carrots

    EPA Science Inventory

    The two predominant arsenic exposure routes are food and water. Estimating the risk from dietary exposures is complicated, owing to the chemical form dependent toxicity of arsenic and the diversity of arsenicals present in dietary matrices. Two aspects of assessing dietary expo...

  17. Ex Priori: Exposure-based Prioritization across Chemical Space

    EPA Science Inventory

    EPA's Exposure Prioritization (Ex Priori) is a simplified, quantitative visual dashboard that makes use of data from various inputs to provide rank-ordered internalized dose metric. This complements other high throughput screening by viewing exposures within all chemical space si...

  18. Articulating uncertainty as part of scientific argumentation during model-based exoplanet detection tasks

    NASA Astrophysics Data System (ADS)

    Lee, Hee-Sun; Pallant, Amy; Pryputniewicz, Sarah

    2015-08-01

    Teaching scientific argumentation has emerged as an important goal for K-12 science education. In scientific argumentation, students are actively involved in coordinating evidence with theory based on their understanding of the scientific content and thinking critically about the strengths and weaknesses of the cited evidence in the context of the investigation. We developed a one-week-long online curriculum module called "Is there life in space?" where students conduct a series of four model-based tasks to learn how scientists detect extrasolar planets through the “wobble” and transit methods. The simulation model allows students to manipulate various parameters of an imaginary star and planet system such as planet size, orbit size, planet-orbiting-plane angle, and sensitivity of telescope equipment, and to adjust the display settings for graphs illustrating the relative velocity and light intensity of the star. Students can use model-based evidence to formulate an argument on whether particular signals in the graphs guarantee the presence of a planet. Students' argumentation is facilitated by the four-part prompts consisting of multiple-choice claim, open-ended explanation, Likert-scale uncertainty rating, and open-ended uncertainty rationale. We analyzed 1,013 scientific arguments formulated by 302 high school student groups taught by 7 teachers. We coded these arguments in terms of the accuracy of their claim, the sophistication of explanation connecting evidence to the established knowledge base, the uncertainty rating, and the scientific validity of uncertainty. We found that (1) only 18% of the students' uncertainty rationale involved critical reflection on limitations inherent in data and concepts, (2) 35% of students' uncertainty rationale reflected their assessment of personal ability and knowledge, rather than scientific sources of uncertainty related to the evidence, and (3) the nature of task such as the use of noisy data or the framing of critiquing scientists' discovery encouraged students' articulation of scientific uncertainty sources in different ways.

  19. Towards a conjoint-based, context-dependent model of task allocation in activity settings: Some numerical experiments

    NASA Astrophysics Data System (ADS)

    Borgers, Aloys; Hofman, Frank; Ponjé, Maarten; Timmermans, Harry

    None of the currently developed activity-based models of transport demand explicitly models task allocation among household members. To fill this gap, the present paper suggests to complement activity-based models of activity scheduling with a context-dependent model of task allocation. That is, it is assumed that the allocation of tasks within households is partly based on such contextual variables as the amount of time a member has to spend on mandatory activities and car availability. In particular, the paper advocates a conjoint-based approach, based on an assignment task as opposed to the traditional ranking, rating or choice response formats. By definition, an assignment task involves a combinatorial explosion of choice alternatives, implying that additional operational decisions to estimate the context-dependent model are required. This study presents the results of various numerical experiments, conducted to better understand the impacts of those decisions on the degree of bias in the parameter estimates of the choice model. The results of these simulations indicate that under particular assumptions, the development and estimation of a conjoint-based, context-dependent model of task allocation within households is feasible.

  20. Factors affecting outdoor exposure in winter: population-based study

    NASA Astrophysics Data System (ADS)

    Mäkinen, Tiina M.; Raatikka, Veli-Pekka; Rytkönen, Mika; Jokelainen, Jari; Rintamäki, Hannu; Ruuhela, Reija; Näyhä, Simo; Hassi, Juhani

    2006-09-01

    The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study ( n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

  1. Imaging Tasks Scheduling for High-Altitude Airship in Emergency Condition Based on Energy-Aware Strategy

    PubMed Central

    Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

    2013-01-01

    Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship's cruising speed based on the distribution of task's deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible. PMID:23864822

  2. Imaging tasks scheduling for high-altitude airship in emergency condition based on energy-aware strategy.

    PubMed

    Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

    2013-01-01

    Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship's cruising speed based on the distribution of task's deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible. PMID:23864822

  3. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    SciTech Connect

    Thompson, C.B.; McArthur, R.D.; Hutchinson, S.W.

    1994-09-01

    As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

  4. Complexity, Accuracy, Fluency and Lexis in Task-Based Performance: A Synthesis of the Ealing Research

    ERIC Educational Resources Information Center

    Skehan, Peter; Foster, Pauline

    2012-01-01

    This chapter will present a research synthesis of a series of studies, termed here the Ealing research. The studies use the same general framework to conceptualise tasks and task performance, enabling easier comparability. The different studies, although each is self-contained, build into a wider picture of task performance. The major point of…

  5. Vision-Based Long-Range 3D Tracking, applied to Underground Surveying Tasks

    NASA Astrophysics Data System (ADS)

    Mossel, Annette; Gerstweiler, Georg; Vonach, Emanuel; Kaufmann, Hannes; Chmelina, Klaus

    2014-04-01

    To address the need of highly automated positioning systems in underground construction, we present a long-range 3D tracking system based on infrared optical markers. It provides continuous 3D position estimation of static or kinematic targets with low latency over a tracking volume of 12 m x 8 m x 70 m (width x height x depth). Over the entire volume, relative 3D point accuracy with a maximal deviation ≤ 22 mm is ensured with possible target rotations of yaw, pitch = 0 - 45° and roll = 0 - 360°. No preliminary sighting of target(s) is necessary since the system automatically locks onto a target without user intervention and autonomously starts tracking as soon as a target is within the view of the system. The proposed system needs a minimal hardware setup, consisting of two machine vision cameras and a standard workstation for data processing. This allows for quick installation with minimal disturbance of construction work. The data processing pipeline ensures camera calibration and tracking during on-going underground activities. Tests in real underground scenarios prove the system's capabilities to act as 3D position measurement platform for multiple underground tasks that require long range, low latency and high accuracy. Those tasks include simultaneously tracking of personnel, machines or robots.

  6. Effects of virtual reality-based training and task-oriented training on balance performance in stroke patients

    PubMed Central

    Lee, Hyung Young; Kim, You Lim; Lee, Suk Min

    2015-01-01

    [Purpose] This study aimed to investigate the clinical effects of virtual reality-based training and task-oriented training on balance performance in stroke patients. [Subjects and Methods] The subjects were randomly allocated to 2 groups: virtual reality-based training group (n = 12) and task-oriented training group (n = 12). The patients in the virtual reality-based training group used the Nintendo Wii Fit Plus, which provided visual and auditory feedback as well as the movements that enabled shifting of weight to the right and left sides, for 30 min/day, 3 times/week for 6 weeks. The patients in the task-oriented training group practiced additional task-oriented programs for 30 min/day, 3 times/week for 6 weeks. Patients in both groups also underwent conventional physical therapy for 60 min/day, 5 times/week for 6 weeks. [Results] Balance and functional reach test outcomes were examined in both groups. The results showed that the static balance and functional reach test outcomes were significantly higher in the virtual reality-based training group than in the task-oriented training group. [Conclusion] This study suggested that virtual reality-based training might be a more feasible and suitable therapeutic intervention for dynamic balance in stroke patients compared to task-oriented training. PMID:26180341

  7. Effects of virtual reality-based training and task-oriented training on balance performance in stroke patients.

    PubMed

    Lee, Hyung Young; Kim, You Lim; Lee, Suk Min

    2015-06-01

    [Purpose] This study aimed to investigate the clinical effects of virtual reality-based training and task-oriented training on balance performance in stroke patients. [Subjects and Methods] The subjects were randomly allocated to 2 groups: virtual reality-based training group (n = 12) and task-oriented training group (n = 12). The patients in the virtual reality-based training group used the Nintendo Wii Fit Plus, which provided visual and auditory feedback as well as the movements that enabled shifting of weight to the right and left sides, for 30 min/day, 3 times/week for 6 weeks. The patients in the task-oriented training group practiced additional task-oriented programs for 30 min/day, 3 times/week for 6 weeks. Patients in both groups also underwent conventional physical therapy for 60 min/day, 5 times/week for 6 weeks. [Results] Balance and functional reach test outcomes were examined in both groups. The results showed that the static balance and functional reach test outcomes were significantly higher in the virtual reality-based training group than in the task-oriented training group. [Conclusion] This study suggested that virtual reality-based training might be a more feasible and suitable therapeutic intervention for dynamic balance in stroke patients compared to task-oriented training. PMID:26180341

  8. Lunar base scenario cost estimates: Lunar base systems study task 6.1

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The projected development and production costs of each of the Lunar Base's systems are described and unit costs are estimated for transporting the systems to the lunar surface and for setting up the system.

  9. Lunar base applications of superconductivity: Lunar base systems study task 3.4

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The application of superconductor technology to several key aspects of an advanced-stage Lunar Base is described. Applications in magnetic energy storage, electromagnetic launching, and radiation shielding are discussed.

  10. Measuring novices' field mapping abilities using an in-class exercise based on expert task analysis

    NASA Astrophysics Data System (ADS)

    Caulkins, J. L.

    2010-12-01

    We are interested in developing a model of expert-like behavior for improving the teaching methods of undergraduate field geology. Our aim is to assist students in mastering the process of field mapping more efficiently and effectively and to improve their ability to think creatively in the field. To examine expert-mapping behavior, a cognitive task analysis was conducted with expert geologic mappers in an attempt to define the process of geologic mapping (i.e. to understand how experts carry out geological mapping). The task analysis indicates that expert mappers have a wealth of geologic scenarios at their disposal that they compare against examples seen in the field, experiences that most undergraduate mappers will not have had. While presenting students with many geological examples in class may increase their understanding of geologic processes, novices still struggle when presented with a novel field situation. Based on the task analysis, a short (45-minute) paper-map-based exercise was designed and tested with 14 pairs of 3rd year geology students. The exercise asks students to generate probable geologic models based on a series of four (4) data sets. Each data set represents a day’s worth of data; after the first “day,” new sheets simply include current and previously collected data (e.g. “Day 2” data set includes data from “Day 1” plus the new “Day 2” data). As the geologic complexity increases, students must adapt, reject or generate new geologic models in order to fit the growing data set. Preliminary results of the exercise indicate that students who produced more probable geologic models, and produced higher ratios of probable to improbable models, tended to go on to do better on the mapping exercises at the 3rd year field school. These results suggest that those students with more cognitively available geologic models may be more able to use these models in field settings than those who are unable to draw on these models for whatever reason. Giving students practice at generating geologic models to explain data may be useful in preparing our students for field mapping exercises.

  11. A distributed computing environment with support for constraint-based task scheduling and scientific experimentation

    SciTech Connect

    Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L.

    1997-04-01

    This paper describes a computing environment which supports computer-based scientific research work. Key features include support for automatic distributed scheduling and execution and computer-based scientific experimentation. A new flexible and extensible scheduling technique that is responsive to a user`s scheduling constraints, such as the ordering of program results and the specification of task assignments and processor utilization levels, is presented. An easy-to-use constraint language for specifying scheduling constraints, based on the relational database query language SQL, is described along with a search-based algorithm for fulfilling these constraints. A set of performance studies show that the environment can schedule and execute program graphs on a network of workstations as the user requests. A method for automatically generating computer-based scientific experiments is described. Experiments provide a concise method of specifying a large collection of parameterized program executions. The environment achieved significant speedups when executing experiments; for a large collection of scientific experiments an average speedup of 3.4 on an average of 5.5 scheduled processors was obtained.

  12. Comparison of Modeling Approaches to Prioritize Chemicals Based on Estimates of Exposure and Exposure Potential

    EPA Science Inventory

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecologic...

  13. An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group Formation

    NASA Astrophysics Data System (ADS)

    Maghami, Mahsa; Sukthankar, Gita

    In this paper, we introduce an agent-based simulation for investigating the impact of social factors on the formation and evolution of task-oriented groups. Task-oriented groups are created explicitly to perform a task, and all members derive benefits from task completion. However, even in cases when all group members act in a way that is locally optimal for task completion, social forces that have mild effects on choice of associates can have a measurable impact on task completion performance. In this paper, we show how our simulation can be used to model the impact of stereotypes on group formation. In our simulation, stereotypes are based on observable features, learned from prior experience, and only affect an agent's link formation preferences. Even without assuming stereotypes affect the agents' willingness or ability to complete tasks, the long-term modifications that stereotypes have on the agents' social network impair the agents' ability to form groups with sufficient diversity of skills, as compared to agents who form links randomly. An interesting finding is that this effect holds even in cases where stereotype preference and skill existence are completely uncorrelated.

  14. Adaptation of a clustered lumpy background model for task-based image quality assessment in x-ray phase-contrast mammography

    PubMed Central

    Zysk, Adam M.; Brankov, Jovan G.; Wernick, Miles N.; Anastasio, Mark A.

    2012-01-01

    Purpose: Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM would have been conducted with human readers. These studies have been limited, however, in part due to the large parameter-space of PCM system configurations and the difficulty of employing expert readers for large-scale studies. It has been proposed that numerical observers can be used to approximate the statistical performance of human readers, thus enabling the study of task-based performance over a large parameter-space. Methods: Methods are presented for task-based image quality assessment of PCM images with a numerical observer, the most significant of which is an adapted lumpy background from the conventional mammography literature that accounts for the unique wavefield propagation physics of PCM image formation and will be used with a numerical observer to assess image quality. These methods are demonstrated by performing a PCM task-based image quality study using a numerical observer. This study employs a signal-known-exactly, background-known-statistically Bayesian ideal observer method to assess the detectability of a calcification object in PCM images when the anode spot size and calcification diameter are varied. Results: The first realistic model for the structured background in PCM images has been introduced. A numerical study demonstrating the use of this background model has compared PCM and conventional mammography detection of calcification objects. The study data confirm the strong PCM calcification detectability dependence on anode spot size. These data can be used to balance the trade-off between enhanced image quality and the potential for motion artifacts that comes with use of a reduced spot size and increased exposure time. Conclusions: A method has been presented for the incorporation of structured breast background data into task-based numerical observer assessment of PCM images. The method adapts conventional background simulation techniques to the wavefield propagation physics necessary for PCM imaging. This method is demonstrated with a simple detection task. PMID:22320800

  15. POPULATION-BASED EXPOSURE MEASUREMENTS IN ARIZONA: A PHASE FIELD STUDY IN SUPPORT OF THE NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY

    EPA Science Inventory

    The objectives of this field study are to determine the distributions of total human exposures to multi-media pollutants in the classes of metals, pesticides, and volatile organic compounds (VOCs) by studying a proportionate-based sample of the total population (with a nested des...

  16. Subclass-based multi-task learning for Alzheimer's disease diagnosis

    PubMed Central

    Suk, Heung-II; Lee, Seong-Whan; Shen, Dinggang

    2014-01-01

    In this work, we propose a novel subclass-based multi-task learning method for feature selection in computer-aided Alzheimer's Disease (AD) or Mild Cognitive Impairment (MCI) diagnosis. Unlike the previous methods that often assumed a unimodal data distribution, we take into account the underlying multipeak1 distribution of classes. The rationale for our approach is that it is highly likely for neuroimaging data to have multiple peaks or modes in distribution, e.g., mixture of Gaussians, due to the inter-subject variability. In this regard, we use a clustering method to discover the multipeak distributional characteristics and define subclasses based on the clustering results, in which each cluster covers a peak in the underlying multipeak distribution. Specifically, after performing clustering for each class, we encode the respective subclasses, i.e., clusters, with their unique codes. In encoding, we impose the subclasses of the same original class close to each other and those of different original classes distinct from each other. By setting the codes as new label vectors of our training samples, we formulate a multi-task learning problem in a ℓ2,1-penalized regression framework, through which we finally select features for classification. In our experimental results on the ADNI dataset, we validated the effectiveness of the proposed method by improving the classification accuracies by 1% (AD vs. Normal Control: NC), 3.25% (MCI vs. NC), 5.34% (AD vs. MCI), and 7.4% (MCI Converter: MCI-C vs. MCI Non-Converter: MCI-NC) compared to the competing single-task learning method. It is remarkable for the performance improvement in MCI-C vs. MCI-NC classification, which is the most important for early diagnosis and treatment. It is also noteworthy that with the strategy of modality-adaptive weights by means of a multi-kernel support vector machine, we maximally achieved the classification accuracies of 96.18% (AD vs. NC), 81.45% (MCI vs. NC), 73.21% (AD vs. MCI), and 74.04% (MCI-C vs. MCI-NC), respectively. PMID:25147522

  17. Conceptual design of a lunar base solar power plant. Lunar base systems study task 3. 3

    SciTech Connect

    Not Available

    1988-08-01

    The best available concepts for a 100 kW Solar Lunar Power Plant based on static and dynamic conversion concepts have been examined. The two concepts which emerged for direct comparison yielded a difference in delivered mass of 35 MT, the mass equivalent of 1.4 lander payloads, in favor of the static concept. The technologies considered for the various elements are either state-of-the-art or near-term. Two photovoltaic cell concepts should receive high priority for development: i.e., amorphous silicon and indium phosphide cells. The amorphous silicon, because it can be made so light weight and rugged; and the indium phosphide, because it shows very high efficiency potential and is reportedly not degraded by radiation. Also the amorphous silicon cells may be mounted on flexible backing that may roll up much like a carpet for compact storage, delivery, and ease of deployment at the base. The fuel cell and electrolysis cell technology is quite well along for lunar base applications, and because both the Shuttle and the forthcoming Space Station incorporate these devices, the status quo will be maintained. Early development of emerging improvements should be implemented so that essential life verification test programs may commence.

  18. Report of the APSAC Task Force on evidence-based service planning guidelines for child welfare.

    PubMed

    Berliner, Lucy; Fitzgerald, Monica M; Dorsey, Shannon; Chaffin, Mark; Ondersma, Steven J; Wilson, Charles

    2015-02-01

    This article presents the American Professional Society on the Abuse of Children (APSAC) Task Force report on the evidence-based service planning (EBSP) approach to child welfare services (CWS) plans and recommendations for practice. The focus of the policy report is on formal psychosocial services. CWS plans prescribe services to promote core child welfare objectives and to benefit children and families. The goal of EBSP is to construct service plans based on the general principles of evidence-based practice and prefer services with empirical support for clinical problems or needs associated with the causes or consequences of child abuse and neglect (CAN). EBSP aims to facilitate an overarching service approach that is collaborative, respectful, and includes services that are most likely to lead to outcomes on both family identified and child welfare mission goals. EBSP emphasizes a focused, assessment-driven, and science-informed approach that both favors plans that are sufficient and avoids overburdening families with compulsory services that address problems which are not directly related to the child welfare CAN referral. PMID:25505157

  19. Non-linguistic learning and aphasia: evidence from a paired associate and feedback-based task.

    PubMed

    Vallila-Rohter, Sofia; Kiran, Swathi

    2013-01-01

    Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory. Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success. In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. PMID:23127795

  20. Sunlight Exposure and Breast Density: A Population-Based Study

    PubMed Central

    Wu, Sheng-Hui; So, Edwin; Lam, Tsz-ping; Woo, Jean; Yuen, PY; Qin, Ling; Ku, Susanna

    2013-01-01

    Purpose This study aims to assess the association of sunlight exposure with breast cancer risk, measured by the breast density assessed from Tabár's mammographic pattern in Chinese women. Methods A total of 676 premenopausal women were recruited to participate in this study, in which 650 completed a validated sunlight exposure questionnaire via telephone. The mammograms were classified according to Tabár's classification for parenchyma, and patterns IV & V and I, II & III indicated respectively high and low risk mammographic patterns for breast cancer. The odds ratios (OR) and 95% confidence intervals (CIs) for sun exposure-related variables were estimated using unconditional logistic regression with adjustment for potential confounders. Results Among 646 participants, women with high breast cancer risk (Tabár's patterns IV &V) had less hours spent in the sun than those with low risk (I, II & III) at any age stage. A higher level of sunlight exposure was associated with a significantly lower risk having high risk Tabár's pattern. Women aged 40 to 44 years who were in the highest tertile of lifetime total hours spent in the sun had a multi-adjusted OR of 0.41 (95% CI, 0.18-0.92; p for trend=0.03) compared with those in the lowest tertile (>2.19 hr/day vs. <1.32 hr/day). For hours spent in the sun across the ages of 6 to 12 years, the comparable OR was 0.37 (95% CI, 0.15-0.91; p for trend=0.03). Conclusion These findings suggest that higher sunlight exposure is related to a lower risk of having high risk breast density pattern in premenopausal women. Our results also suggest the most relevant period of exposure is during earlier life. PMID:23843849

  1. Object-based task-level control: A hierarchical control architecture for remote operation of space robots

    NASA Technical Reports Server (NTRS)

    Stevens, H. D.; Miles, E. S.; Rock, S. J.; Cannon, R. H.

    1994-01-01

    Expanding man's presence in space requires capable, dexterous robots capable of being controlled from the Earth. Traditional 'hand-in-glove' control paradigms require the human operator to directly control virtually every aspect of the robot's operation. While the human provides excellent judgment and perception, human interaction is limited by low bandwidth, delayed communications. These delays make 'hand-in-glove' operation from Earth impractical. In order to alleviate many of the problems inherent to remote operation, Stanford University's Aerospace Robotics Laboratory (ARL) has developed the Object-Based Task-Level Control architecture. Object-Based Task-Level Control (OBTLC) removes the burden of teleoperation from the human operator and enables execution of tasks not possible with current techniques. OBTLC is a hierarchical approach to control where the human operator is able to specify high-level, object-related tasks through an intuitive graphical user interface. Infrequent task-level command replace constant joystick operations, eliminating communications bandwidth and time delay problems. The details of robot control and task execution are handled entirely by the robot and computer control system. The ARL has implemented the OBTLC architecture on a set of Free-Flying Space Robots. The capability of the OBTLC architecture has been demonstrated by controlling the ARL Free-Flying Space Robots from NASA Ames Research Center.

  2. Derivation of safe health-based exposure limits for potential consumer exposure to styrene migrating into food from food containers.

    PubMed

    Gelbke, Heinz-Peter; Banton, Marcy; Faes, Eric; Leibold, Edgar; Pemberton, Mark; Duhayon, Sophie

    2014-02-01

    Residual styrene present in polystyrene food packaging may migrate into food at low levels. To assure safe use, safe exposure levels are derived for consumers potentially exposed via food using No/Low Adverse Effect Levels from animal and human studies and assessment factors proposed by European organisations (EFSA, ECHA, ECETOC). Ototoxicity and developmental toxicity in rats and human ototoxicity and effects on colour discrimination have been identified as the most relevant toxicological properties for styrene health assessments. Safe exposure levels derived from animal studies with assessment factors of EFSA and ECHA were expectedly much lower than those using the ECETOC approach. Comparable safe exposure levels were obtained from human data with all sets of assessment factors while ototoxicity in rats led to major differences. The safe exposure levels finally selected based on criteria of science and health protection converged to the range of 90-120 mg/person/d. Assuming a consumption of 1 kg food/d for an adult, this translates to 90 mg styrene migration into 1 kg food as safe for consumers. This assessment supports a health based Specific Migration Limit of 90 ppm, a value somewhat higher than the current overall migration limit of 60 ppm in the European Union. PMID:24316211

  3. From PPP and CALL/MALL to a Praxis of Task-Based Teaching and Mobile Assisted Language Use

    ERIC Educational Resources Information Center

    Jarvis, Huw

    2015-01-01

    Two of the most significant trends in TESOL (Teachers of English to Speakers of Other Languages) over the last twenty years or so are the rise of task­-based language teaching (TBLT) and the growth of technology. With TBLT there is a challenging of more traditional structure-based models of delivery, and the increased capacity and mobility of…

  4. A Task Analysis of Staff Development Personnel in Selected Public School Districts. School Based Teacher Educators, Number 6.

    ERIC Educational Resources Information Center

    Stell, Eugenia Ann; And Others

    This study was conducted to provide data as a basis for deriving school-based teacher educator competencies. The task analysis approach, using data derived from interviews, was selected as the basis of the study and as one of several methods for identifying competencies of the school-based teacher educator. The interviews were designed to reflect…

  5. Comparison of Deck- and Trial-Based Approaches to Advantageous Decision Making on the Iowa Gambling Task

    ERIC Educational Resources Information Center

    Visagan, Ravindran; Xiang, Ally; Lamar, Melissa

    2012-01-01

    We compared the original deck-based model of advantageous decision making assessed with the Iowa Gambling Task (IGT) with a trial-based approach across behavioral and physiological outcomes in 33 younger adults (15 men, 18 women; 22.2 [plus or minus] 3.7 years of age). One administration of the IGT with simultaneous measurement of skin conductance…

  6. Advanced Exposure Metrics For Chemical Risk Analysis: Systems Biology and 'Omic-based Biomarkers for Exposure Reconstruction

    EPA Science Inventory

    Direct measurement of human exposure to environmental contaminants in real time (when the exposure is actually occurring) is rare and difficult to obtain. This frustrates both exposure assessments and investigations into the linkage between chemical exposure and human disease. ...

  7. Development of the Task-Based Expert System for Machine Fault Diagnosis

    NASA Astrophysics Data System (ADS)

    Bo, Ma; Zhi-nong, Jiang; Zhong-qing, Wei

    2012-05-01

    The operating mechanism of expert systems widely used in fault diagnosis is to formulate a set of diagnostic rules, according to the mechanism and symptoms of faults, in order to instruct the fault diagnosis or directly give diagnostic results. In practice, due to differences existing in such aspects as production technology, drivers, etc., a certain fault may derive from different causes, which will lead to a lower diagnostic accuracy of expert systems. Besides, a variety of expert systems now available have a dual problem of low generality and low expandability, of which the former can lead to the repeated development of expert systems for different machines, while the latter restricts users from expanding the system. Aimed at these problems, a type of task-based software architecture of expert system is proposed in this paper, which permits a specific optimization based on a set of common rules, and allows users to add or modify rules on a man-machine dialog so as to keep on absorbing and improving the expert knowledge. Finally, the integration of the expert system with the condition monitoring system to implement the automatic and semi-automatic diagnosis is introduced.

  8. Game-Based Approaches' Pedagogical Principles: Exploring Task Constraints in Youth Soccer.

    PubMed

    Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

    2015-06-27

    This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches. PMID:26240668

  9. Game-Based Approaches’ Pedagogical Principles: Exploring Task Constraints in Youth Soccer

    PubMed Central

    Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

    2015-01-01

    This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches. PMID:26240668

  10. Explicit and implicit tasks for assessing hedonic-versus nutrition-based attitudes towards food in French children.

    PubMed

    Monnery-Patris, Sandrine; Marty, Lucile; Bayer, Frédéric; Nicklaus, Sophie; Chambaron, Stéphanie

    2016-01-01

    Attitudes are important precursors of behaviours. This study aims to compare the food attitudes (i.e., hedonic- and nutrition-based) of children using both an implicit pairing task and an explicit forced-choice categorization task suitable for the cognitive abilities of 5- to 11-year-olds. A dominance of hedonically driven attitudes was expected for all ages in the pairing task, designed to elicit affective and spontaneous answers, whereas a progressive emergence of nutrition-based attitudes was expected in the categorization task, designed to involve deliberate analyses of the costs/benefits of foods. An additional exploratory goal was to evaluate differences in the attitudes of normal and overweight children in both tasks. Children from 3 school levels (n = 194; mean age = 8.03 years) were individually tested on computers in their schools. They performed a pairing task in which the tendencies to associate foods with nutritional vs. culinary contexts were assessed. Next, they were asked to categorize each food into one of the following four categories: "yummy", "yucky" (i.e., hedonic categories), "makes you strong", or"makes you fat" (i.e., nutritional categories). The hedonic/culinary pairs were very frequently selected (81% on average), and this frequency significantly increased through school levels. In contrast, in the categorization task, a significant increase in nutrition-driven categorizations with school level was observed. Additional analyses revealed no differences in the food attitudes between the normal and overweight children in the pairing task, and a tendency towards lower hedonic categorizations among the overweight children. Culinary associations can reflect cultural learning in the French context where food pleasure is dominant. In contrast, the progressive emergence of cognitively driven attitudes with age may reflect the cognitive development of children who are more reasonable and influenced by social norms. PMID:26522508

  11. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    EPA Science Inventory

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient d...

  12. PHARMACOKINETICALLY BASED RISK ASSESSMENT OF WORKPLACE EXPOSURE OF BENZENE

    EPA Science Inventory

    Cancer risk from exposure to benzene for a working lifetime was estimated from data obtained in studies with rodents. ancers of the Zymbal gland and the blood-forming system were selected as endpoints for the assessment because of their consistent occurrence. he combined metaboli...

  13. Physiologically-based pharmacokinetic (PBPK) models in human exposure assessment

    SciTech Connect

    Krishnan, K.

    1995-12-31

    The potential dose received by an individual during defined exposure situations can be determined using personal dosimeters or estimated by combining information on exposure scenarios with the environmental concentration (C.) of chemicals. With the latter approach, not only the potential dose but also the internal dose (i.e., amount of chemical that has been absorbed and available for interaction with receptors) and biologically-effective dose (i.e., amount of chemical that actually reaches the cellular sites where interaction with macromolecules occur) can be estimated if C. is provided as an input to PBPK models. These models are mathematical representations of the interrelationships among the critical determinants of the absorption, distribution, metabolism and excretion of chemicals in biota. Since the compartments in this model correspond to biologically relevant tissues or tissue groups, the amount of chemical reaching specific target organ(s) can be estimated. Further, the PBPK models permit the use of biological monitoring data such as urinary levels of metabolites, hemoglobin adduct levels, and alveolar air concentrations, to reconstruct the exposure levels and scenarios for specific subgroups of populations. These models are also useful in providing estimates of target tissue dose in humans simultaneously exposed to chemicals in various media (air, water, soil, food) by different routes (oral, dermal, inhalation). Several examples of exposure assessment for volatile organic chemicals using PBPK models for mammals will be presented, and the strategies for development of these models for other classes of chemicals highlighted.

  14. Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies

    PubMed Central

    Safavynia, Seyed A.

    2013-01-01

    We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions. PMID:23100133

  15. Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies.

    PubMed

    Safavynia, Seyed A; Ting, Lena H

    2013-01-01

    We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions. PMID:23100133

  16. Machine Learning Based Online Performance Prediction for Runtime Parallelization and Task Scheduling

    SciTech Connect

    Li, J; Ma, X; Singh, K; Schulz, M; de Supinski, B R; McKee, S A

    2008-10-09

    With the emerging many-core paradigm, parallel programming must extend beyond its traditional realm of scientific applications. Converting existing sequential applications as well as developing next-generation software requires assistance from hardware, compilers and runtime systems to exploit parallelism transparently within applications. These systems must decompose applications into tasks that can be executed in parallel and then schedule those tasks to minimize load imbalance. However, many systems lack a priori knowledge about the execution time of all tasks to perform effective load balancing with low scheduling overhead. In this paper, we approach this fundamental problem using machine learning techniques first to generate performance models for all tasks and then applying those models to perform automatic performance prediction across program executions. We also extend an existing scheduling algorithm to use generated task cost estimates for online task partitioning and scheduling. We implement the above techniques in the pR framework, which transparently parallelizes scripts in the popular R language, and evaluate their performance and overhead with both a real-world application and a large number of synthetic representative test scripts. Our experimental results show that our proposed approach significantly improves task partitioning and scheduling, with maximum improvements of 21.8%, 40.3% and 22.1% and average improvements of 15.9%, 16.9% and 4.2% for LMM (a real R application) and synthetic test cases with independent and dependent tasks, respectively.

  17. Learners' Perceptions of the Benefits of Voice Tool-Based Tasks on Their Spoken Performance

    ERIC Educational Resources Information Center

    Wilches, Astrid

    2014-01-01

    The purpose of this study is to investigate learners' perceptions of the benefits of tasks using voice tools to reinforce their oral skills. Additionally, this study seeks to determine what aspects of task design affected the students' perceptions. Beginner learners aged 18 to 36 with little or no experience in the use of technological tools for…

  18. Task-Based Language Learning and Teaching: An Action-Research Study

    ERIC Educational Resources Information Center

    Calvert, Megan; Sheen, Younghee

    2015-01-01

    The creation, implementation, and evaluation of language learning tasks remain a challenge for many teachers, especially those with limited experience with using tasks in their teaching. This action-research study reports on one teacher's experience of developing, implementing, critically reflecting on, and modifying a language learning task…

  19. Talk and Task Mastery: The Importance of Socially Shared Talk during Computer-Based Problem Solving

    ERIC Educational Resources Information Center

    Hagstrom, Fran; White, Michelle

    2006-01-01

    In order to examine more closely the ways that children use socially constructed dialogue to mediate task mastery a hierarchical set of computer tasks were presented in an animated game format (ToonTalk) to three adult/child (US Kindergarten) dyads over five sessions. Transcriptions of the adult-child talk were used to determine (1) the types of…

  20. Lunar surface construction and assembly equipment study: Lunar Base Systems Study (LBSS) task 5.3

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A set of construction and assembly tasks required on the lunar surface was developed, different concepts for equipment applicable to the tasks determined, and leading candidate systems identified for future conceptual design. Data on surface construction and assembly equipment systems are necessary to facilitate an integrated review of a complete lunar scenario.

  1. Biology Based Lung Cancer Model for Chronic Low Radon Exposures

    SciTech Connect

    Truta-Popa, Lucia-Adina; Hofmann, Werner; Fakir, Hatim; Cosma, Constantin

    2008-08-07

    Low dose effects of alpha particles at the tissue level are characterized by the interaction of single alpha particles, affecting only a small fraction of the cells within that tissue. Alpha particle intersections of bronchial target cells during a given exposure period were simulated by an initiation-promotion model, formulated in terms of cellular hits within the cycle time of the cell (dose-rate) and then integrated over the whole exposure period (dose). For a given average number of cellular hits during the lifetime of bronchial cells, the actual number of single and multiple hits was selected from a Poisson distribution. While oncogenic transformation is interpreted as the primary initiation step, stimulated mitosis by killing adjacent cells is assumed to be the primary radiological promotion event. Analytical initiation and promotion functions were derived from experimental in vitro data on oncogenic transformation and cellular survival.To investigate the shape of the lung cancer risk function at chronic, low level exposures in more detail, additional biological factors describing the tissue response and operating specifically at low doses were incorporated into the initiation-promotion model. These mechanisms modifying the initial response at the cellular level were: adaptive response, genomic instability, induction of apoptosis by surrounding cells, and detrimental as well as protective bystander mechanisms. To quantify the effects of these mechanisms as functions of dose, analytical functions were derived from the experimental evidence presently available. Predictions of lung cancer risk, including these mechanisms, exhibit a distinct sublinear dose-response relationship at low exposures, particularly for very low exposure rates.

  2. Windowed correlation: a suitable tool for providing dynamic fMRI-based functional connectivity neurofeedback on task difficulty.

    PubMed

    Zilverstand, Anna; Sorger, Bettina; Zimmermann, Jan; Kaas, Amanda; Goebel, Rainer

    2014-01-01

    The goal of neurofeedback training is to provide participants with relevant information on their ongoing brain processes in order to enable them to change these processes in a meaningful way. Under the assumption of an intrinsic brain-behavior link, neurofeedback can be a tool to guide a participant towards a desired behavioral state, such as a healthier state in the case of patients. Current research in clinical neuroscience regarding the most robust indicators of pathological brain processes in psychiatric and neurological disorders indicates that fMRI-based functional connectivity measures may be among the most important biomarkers of disease. The present study therefore investigated the general potential of providing fMRI neurofeedback based on functional correlations, computed from short-window time course data at the level of single task periods. The ability to detect subtle changes in task performance with block-wise functional connectivity measures was evaluated based on imaging data from healthy participants performing a simple motor task, which was systematically varied along two task dimensions representing two different aspects of task difficulty. The results demonstrate that fMRI-based functional connectivity measures may provide a better indicator for an increase in overall (motor) task difficulty than activation level-based measures. Windowed functional correlations thus seem to provide relevant and unique information regarding ongoing brain processes, which is not captured equally well by standard activation level-based neurofeedback measures. Functional connectivity markers, therefore, may indeed provide a valuable tool to enhance and monitor learning within an fMRI neurofeedback setup. PMID:24465794

  3. Exposure to indoor tanning in France: a population based study

    PubMed Central

    2013-01-01

    Background Tanning lamp sessions have increased in Europe in recent years. Recent epidemiological studies have confirmed a proven link between melanoma and artificial UV exposure. However, in France, little information is available to determine the exposure of the population. This article presents the results from the ‘Baromètre cancer 2010’ concerning the proportion of users exposed to artificial UV radiation in France, their characteristics and level of information on the risks associated. Methods A two stage random sampling telephone survey assisted by CATI system (household, individual) was performed from 3 April 2010 to 7 August 2010 on a sample of 3,359 people aged 15 to 75 years old. Results In 2010, 13.4% of the French population reported to have tanning lamp sessions at least once in their lifetime and 3.5% of the total population reported the use of artificial UV radiation over the last twelve months. Exposure over the last twelve months is most commonly seen among females (5.0%) and young population between 20–25 years old (9.6%). In addition, 3.5% of those under 18 years report having attended UV booths at least once during their lifetime even though they are forbidden to minors. Moreover, more than one the third of users reported more than 10 exposures within a year. The places of exposure cited most often were beauty salons (50%) and tanning centers (46%). Only 49.2% of those surveyed felt that they were well informed on the risks of cancer associated with UV booths. Furthermore, the population was found to have misconceptions about artificial UV radiation. One quarter of the population, believe that artificial UV radiation use before vacation protects the skin from sunburn. Conclusions This first study on artificial UV radiation exposure in France has better quantified and characterized the users. It has also defined the state of knowledge and the perception of risk by the general French population. This work will contribute to determine actions of prevention to reduce cancer risk related to artificial UV radiation. PMID:23617560

  4. A computer-based interactive game to train persons with cognitive impairments to perform recycling tasks independently.

    PubMed

    Chang, Yao-Jen; Kang, Ya-Shu; Liu, Fang-Lin

    2014-12-01

    This study assessed the possibility of training three people with cognitive impairments using a computer-based interactive game. A game was designed to provide task prompts in recycling scenarios, identify incorrect task steps on the fly, and help users learn to make corrections. Based on a multiple baseline design, the data showed that the three participants considerably increased their target response, which improved their vocational job skills during the intervention phases and enabled them to maintain the acquired job skills after intervention. The practical and developmental implications of the results are discussed. PMID:25262012

  5. Valence-based Word-Face Stroop task reveals differential emotional interference in patients with major depression.

    PubMed

    Başgöze, Zeynep; Gönül, Ali Saffet; Baskak, Bora; Gökçay, Didem

    2015-10-30

    Word-Face Stroop task creates emotional conflict between affective words and affective faces. In this task, healthy participants consistently slow down while responding to incongruent cases. Such interference related slowdown is associated with recruitment of inhibitory processes to eliminate task-irrelevant information. We created a valence-based Word-Face Stroop task, in which participants were asked to indicate whether the words in the foreground are positive, negative or neutral. Healthy participants were faster and more accurate than un-medicated patients with major depression disorder (MDD). In addition, a significant congruence by group interaction is observed: healthy participants slowed down for incongruent cases, but MDD patients did not. Furthermore, for the negative words, healthy individuals made more errors while responding to incongruent cases but MDD patients made the lowest number of errors for this category. The emotional percepts of the patients were intact, because correct response rates in word valence judgments for positive/negative words, and reaction times for happy/sad faces had similar patterns with those of controls. These findings are supported by the analytical rumination interpretation of depression: patients lose speed/accuracy in laboratory tasks due to processing load spent during continuous rumination. However, for tasks in line with their preoccupation, continual practice makes the patients more vigilant and adept. PMID:26272019

  6. The Relationship between Event-Based Prospective Memory and Ongoing Task Performance in Chimpanzees (Pan troglodytes)

    PubMed Central

    Evans, Theodore A.; Perdue, Bonnie; Beran, Michael J.

    2014-01-01

    Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. PMID:25372809

  7. The relationship between event-based prospective memory and ongoing task performance in chimpanzees (Pan troglodytes).

    PubMed

    Evans, Theodore A; Perdue, Bonnie; Beran, Michael J

    2014-01-01

    Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. PMID:25372809

  8. Neural Bases of Unconscious Error Detection in a Chinese Anagram Solution Task: Evidence from ERP Study.

    PubMed

    Yin, Hua-Zhan; Li, Dan; Yang, Junyi-; Li, Wei; Qiu, Jiang; Chen, Ying-Yu

    2016-01-01

    In everyday life, error monitoring and processing are important for improving ongoing performance in response to a changing environment. However, detecting an error is not always a conscious process. The temporal activation patterns of brain areas related to cognitive control in the absence of conscious awareness of an error remain unknown. In the present study, event-related potentials (ERPs) in the brain were used to explore the neural bases of unconscious error detection when subjects solved a Chinese anagram task. Our ERP data showed that the unconscious error detection (UED) response elicited a more negative ERP component (N2) than did no error (NE) and detect error (DE) responses in the 300-400-ms time window, and the DE elicited a greater late positive component (LPC) than did the UED and NE in the 900-1200-ms time window after the onset of the anagram stimuli. Taken together with the results of dipole source analysis, the N2 (anterior cingulate cortex) might reflect unconscious/automatic conflict monitoring, and the LPC (superior/medial frontal gyrus) might reflect conscious error recognition. PMID:27149300

  9. Neural Bases of Unconscious Error Detection in a Chinese Anagram Solution Task: Evidence from ERP Study

    PubMed Central

    Yang, Junyi-; Li, Wei; Qiu, Jiang; Chen, Ying-yu

    2016-01-01

    In everyday life, error monitoring and processing are important for improving ongoing performance in response to a changing environment. However, detecting an error is not always a conscious process. The temporal activation patterns of brain areas related to cognitive control in the absence of conscious awareness of an error remain unknown. In the present study, event-related potentials (ERPs) in the brain were used to explore the neural bases of unconscious error detection when subjects solved a Chinese anagram task. Our ERP data showed that the unconscious error detection (UED) response elicited a more negative ERP component (N2) than did no error (NE) and detect error (DE) responses in the 300–400-ms time window, and the DE elicited a greater late positive component (LPC) than did the UED and NE in the 900–1200-ms time window after the onset of the anagram stimuli. Taken together with the results of dipole source analysis, the N2 (anterior cingulate cortex) might reflect unconscious/automatic conflict monitoring, and the LPC (superior/medial frontal gyrus) might reflect conscious error recognition. PMID:27149300

  10. Two Commentaries on Ron Sheen's "A Critical Analysis of the Advocacy of the Task-Based Syllabus." A Reader Reacts... [and] On the Advocacy of the Task-Based Syllabus [and] The Author Responds....

    ERIC Educational Resources Information Center

    Nunan, David; And Others

    1994-01-01

    An author, David Nunan, responds to a previous article that criticizes his advocacy of task-based syllabuses. Another author, Michael Long, points out inaccuracies in the criticism, and the author of the criticism, Ron Sheen, defends his earlier claim. (45 references) (JL)

  11. Task Performance in Astronomical Adaptive Optics

    PubMed Central

    Barrett, Harrison H.; Myers, Kyle J.; Devaney, Nicholas; Dainty, J. C.; Caucci, Luca

    2010-01-01

    In objective or task-based assessment of image quality, figures of merit are defined by the performance of some specific observer on some task of scientific interest. This methodology is well established in medical imaging but is just beginning to be applied in astronomy. In this paper we survey the theory needed to understand the performance of ideal or ideal-linear (Hotelling) observers on detection tasks with adaptive-optical data. The theory is illustrated by discussing its application to detection of exoplanets from a sequence of short-exposure images. PMID:20890393

  12. What’s special about task in dystonia? A voxel-based morphometry and diffusion weighted imaging study

    PubMed Central

    Ramdhani, Ritesh A.; Kumar, Veena; Velickovic, Miodrag; Frucht, Steven J.; Tagliati, Michele; Simonyan, Kristina

    2014-01-01

    Background Numerous brain imaging studies have demonstrated structural changes in the basal ganglia, thalamus, sensorimotor cortex and cerebellum across different forms of primary dystonia. However, our understanding of brain abnormalities contributing to the clinically well-described phenomenon of task-specificity in dystonia remained limited. Methods We used high-resolution MRI with voxel-based morphometry and diffusion tensor imaging with tract-based spatial statistics of fractional anisotropy to examine gray and white matter organization in two task-specific dystonia forms, writer’s cramp and laryngeal dystonia, and two non-task-specific dystonia forms, cervical dystonia and blepharospasm. Results A direct comparison between the both dystonia forms revealed that characteristic gray matter volumetric changes in task-specific dystonia involve the brain regions responsible for sensorimotor control during writing and speaking, such as primary somatosensory cortex, middle frontal gyrus, superior/inferior temporal gyrus, middle/posterior cingulate cortex, occipital cortex as well as the striatum and cerebellum (lobules VI-VIIa). These gray matter changes were accompanied by white matter abnormalities in the premotor cortex, middle/inferior frontal gyrus, genu of the corpus callosum, anterior limb/genu of the internal capsule, and putamen. Conversely, gray matter volumetric changes in non-task-specific group were limited to the left cerebellum (lobule VIIa) only, while white matter alterations were found to underlie the primary sensorimotor cortex, inferior parietal lobule and middle cingulate gyrus. Conclusion Distinct microstructural patterns in task-specific and non-task-specific dystonias may represent neuroimaging markers and provide evidence that these two dystonia subclasses likely follow divergent pathophysiological mechanisms precipitated by different triggers. PMID:24925463

  13. Orbital cortex neuronal responses during an odor-based conditioned associative task in rats.

    PubMed

    Yonemori, M; Nishijo, H; Uwano, T; Tamura, R; Furuta, I; Kawasaki, M; Takashima, Y; Ono, T

    2000-01-01

    Neuronal activity in the rat orbital cortex during discrimination of various odors [five volatile organic compounds (acetophenone, isoamyl acetate, cyclohexanone, p-cymene and 1,8-cineole), and food- and cosmetic-related odorants (black pepper, cheese, rose and perfume)] and other conditioned sensory stimuli (tones, light and air puff) was recorded and compared with behavioral responses to the same odors (black pepper, cheese, rose and perfume). In a neurophysiological study, the rats were trained to lick a spout that protruded close to its mouth to obtain sucrose or intracranial self-stimulation reward after presentation of conditioned stimuli. Of 150 orbital cortex neurons recorded during the task, 65 responded to one or more types of sensory stimuli. Of these, 73.8% (48/65) responded during presentation of an odor. Although the mean breadth of responsiveness (entropy) of the olfactory neurons based on the responses to five volatile organic compounds and air (control) was rather high (0.795), these stimuli were well discriminated in an odor space resulting from multidimensional scaling using Pearson's correlation coefficients between the stimuli. In a behavioral study, a rat was housed in an equilateral octagonal cage, with free access to food and choice among eight levers, four of which elicited only water (no odor, controls), and four of which elicited both water and one of four odors (black pepper, cheese, rose or perfume). Lever presses for each odor and control were counted. Distributions of these five stimuli (four odors and air) in an odor space derived from the multidimensional scaling using Pearson's correlation coefficients based on behavioral responses were very similar to those based on neuronal responses to the same five stimuli. Furthermore, Pearson's correlation coefficients between the same five stimuli based on the neuronal responses and those based on behavioral responses were significantly correlated. The results demonstrated a pivotal role of the rat orbital cortex in olfactory sensory processing and suggest that the orbital cortex is important in the manifestation of various motivated behaviors of the animals, including odor-guided motivational behaviors (odor preference). PMID:10670436

  14. Paleoglaciation of the Tibetan Plateau based on exposure ages and ELA depression estimates

    NASA Astrophysics Data System (ADS)

    Heyman, Jakob

    2014-05-01

    The Tibetan Plateau holds a major part of all glaciers outside the polar regions and an ample record of past glaciations. The glacial history of the Tibetan Plateau has attracted significant interest, with a large body of research investigating the extent, timing, and climatic implications of past glaciations. Here I present an extensive compilation of exposure ages and equilibrium line altitude (ELA) depression estimates from glacial deposits across the Tibetan Plateau to address the timing and degree of past glaciations. I compiled Be-10 exposure age data for a total of 1877 samples and recalculated exposure ages using an updated (lower) global Be-10 production rate. All samples were organized in groups of individual glacial deposits where each deposit represents one glacial event enabling evaluation of the exposure age clustering. For each glacial deposit I estimated the ELA depression based on a simple toe to headwall ratio approach using Google Earth. To discriminate good (well-clustered) from poor (scattered) exposure age groups the glacial deposits were divided into three groups based on exposure age clustering. A major part of the glacial deposits have scattered exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered exposure age groups are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak in age between 10 and 30 ka, indicating glacial advances during the global last glacial maximum (LGM). A large number of exposure ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but a major part is remarkably low. Average ELA depressions of 333 ± 191 m for the LGM and 494 ± 280 m for the pre-LGM exposure indicate restricted glacier expansion and limited glacial cooling.

  15. Can time-based decay explain temporal distinctiveness effects in task switching?

    PubMed

    Grange, James A; Cross, Ellen

    2015-01-01

    In task switching, extending the response-cue interval (RCI) reduces the switch cost--the detriment to performance when switching compared to repeating tasks. This reduction has been used as evidence for the existence of task-set decay processes. Recently, this has been challenged by the observation of sequential dependencies on the RCI effect: switch cost is only reduced at longer RCIs when the previous trial had a short RCI. This trial-wise variation of RCI is thought to affect the temporal distinctiveness (TD) of a previous task's episodic trace, affecting the probability of its automatic retrieval on the current trial; importantly, TD is thought to be independent of the current trial's RCI. The present study highlights a dependency between the current RCI and TD, and demonstrates that a decay model can reproduce some patterns of data attributed to TD. Further, the decay account makes a strong prediction when TD is held constant: repetition response times should slow as the RCI increases, and switch response times should be facilitated. This prediction was tested via re-analysis of extant data and three experiments. The re-analysis provided some evidence for the decay account, but Experiments 1 and 2 report slowing for task repetition and switch trials, which cannot be explained by a task-set decay process. Experiment 3, which utilized tasks requiring perceptual judgements, showed small evidence for decay. We conclude that the data are largely consistent with the TD account and that the evidence for decay of higher-level task-sets is not convincing. PMID:25028178

  16. Towards an effective cross-task mental workload recognition model using electroencephalography based on feature selection and support vector machine regression.

    PubMed

    Ke, Yufeng; Qi, Hongzhi; Zhang, Lixin; Chen, Shanguang; Jiao, Xuejun; Zhou, Peng; Zhao, Xin; Wan, Baikun; Ming, Dong

    2015-11-01

    Electroencephalographic (EEG) has been believed to be a potential psychophysiological measure of mental workload. There however remain a number of challenges in building a generalized mental workload recognition model, one of which includes the inability of an EEG-based workload classifier trained on a specific task to handle other tasks. The primary goal of the present study was to examine the possibility of addressing this challenge using feature selection and regression model. Support vector machine classifier and regression models were examined under within-task conditions (trained and tested on the same task) and cross-task conditions (trained on one task and tested on another task) for well-trained verbal and spatial n-back tasks. A specifically designed cross-task recursive feature elimination (RFE) based feature selection was used to handle the possible causes responsible for the deterioration of the performance of cross-task regression model. The within-task classification and regression performed fairly well. Cross-task classification and regression performance, however, deteriorated to unacceptable levels (around chance level). Trained and tested with the most robust feature subset selected by cross-task RFE, the performance of cross-task regression was significantly improved, and there were no significant changes in the performance of within-task regression. It can be inferred that workload-related features can be picked out from those which have been contaminated using RFE, and regression models rather than classifiers may be a wiser choice for cross-task conditions. These encouraging results suggest that the cross-task workload recognition model built in this study is much more generalizable across task when compared to the model built in traditional way. PMID:26493860

  17. Antecedent Assessment and Assessment-Based Treatment of Off-Task Behavior in a Child Diagnosed with Attention Deficit-Hyperactivity Disorder (ADHD).

    ERIC Educational Resources Information Center

    Flood, William A.; Wilder, David A.

    2002-01-01

    Antecedent assessment and assessment-based intervention for off-task behavior by an 11-year-old with attention deficit hyperactivity disorder is reported. Assessment correlated off-task behavior with difficult academic tasks; intervention included functional communication training that focused on teaching the child to request assistance, as well…

  18. EPA-Expo-Box: A web-based Toolbox for Exposure Assessors

    EPA Science Inventory

    EPA EXPOsure toolBOX, or EPA-Expo-Box, is a web-based toolbox that has been developed by EPAs Office of Research and Development (ORD), National Center for Environmental Assessment (NCEA). It is intended for exposure and risk assessors and it comprises a series of Tool Set...

  19. EPA-Expo-Box: A web-based Toolbox for Exposure Assessors

    EPA Science Inventory

    EPA EXPOsure toolBOX, or EPA-Expo-Box, is a web-based toolbox that has been developed by EPA’s Office of Research and Development (ORD), National Center for Environmental Assessment (NCEA). It is intended for exposure and risk assessors and it comprises a series of Tool Set...

  20. Fetal Implications of Diagnostic Radiation Exposure During Pregnancy: Evidence-based Recommendations.

    PubMed

    Rimawi, Bassam H; Green, Victoria; Lindsay, Michael

    2016-06-01

    The purpose of this article is to review the fetal and long-term implications of diagnostic radiation exposure during pregnancy. Evidence-based recommendations for radiologic imaging modalities utilizing exposure of diagnostic radiation during pregnancy, including conventional screen-film mammography, digital mammography, tomosynthesis, and contrast-enhanced mammography are described. PMID:26982251

  1. Using a physiologically based pharmacokinetic model to link urinary biomarker concentrations to dietary exposure of perchlorate

    EPA Science Inventory

    Exposure to perchlorate is widespread in the United States and many studies have attempted to character the perchlorate exposure by estimating the average daily intakes of perchlorate. These approaches provided population-based estimates, but did not provide individual-level exp...

  2. A Comparison of Exposure Control Procedures in CAT Systems Based on Different Measurement Models for Testlets

    ERIC Educational Resources Information Center

    Boyd, Aimee M.; Dodd, Barbara; Fitzpatrick, Steven

    2013-01-01

    This study compared several exposure control procedures for CAT systems based on the three-parameter logistic testlet response theory model (Wang, Bradlow, & Wainer, 2002) and Masters' (1982) partial credit model when applied to a pool consisting entirely of testlets. The exposure control procedures studied were the modified within 0.10 logits…

  3. A Program Based on Task-Based Teaching Approach to Develop Creative Thinking Teaching Skills for Female Science Teachers in Kingdom of Saudi Arabia (KSA)

    ERIC Educational Resources Information Center

    Ibrahim, Manal Hassan Mohammed Bin

    2015-01-01

    This study aimed at developing creative thinking teaching skills for female science teachers in Kingdom of Saudi Arabia (KSA) through designing a program based on task-based teaching approach. The problem of the study was specified as the weakness of creative thinking teaching skills for science teachers in KSA and the need for programs based on…

  4. Computer-Based Assessment in E-Learning: A Framework for Constructing "Intermediate Constraint" Questions and Tasks for Technology Platforms

    ERIC Educational Resources Information Center

    Scalise, Kathleen; Gifford, Bernard

    2006-01-01

    Technology today offers many new opportunities for innovation in educational assessment through rich new assessment tasks and potentially powerful scoring, reporting and real-time feedback mechanisms. One potential limitation for realizing the benefits of computer-based assessment in both instructional assessment and large scale testing comes in…

  5. A Location-Based Prompting System to Transition Autonomously through Vocational Tasks for Individuals with Cognitive Impairments

    ERIC Educational Resources Information Center

    Chang, Yao-Jen; Wang, Tsen-Yung; Chen, Yan-Ru

    2011-01-01

    This study assessed the possibility of training two individuals with cognitive impairments using location-based task prompting system in a supported employment program. This study was carried out according to an ABAB sequence in which A represented the baseline and B represented intervention phases. Data showed that the two participants…

  6. A Location-Based Prompting System to Transition Autonomously through Vocational Tasks for Individuals with Cognitive Impairments

    ERIC Educational Resources Information Center

    Chang, Yao-Jen; Wang, Tsen-Yung; Chen, Yan-Ru

    2011-01-01

    This study assessed the possibility of training two individuals with cognitive impairments using location-based task prompting system in a supported employment program. This study was carried out according to an ABAB sequence in which A represented the baseline and B represented intervention phases. Data showed that the two participants

  7. The Effect of Video-Based Tasks in Listening Comprehension of Iranian Pre-Intermediate EFL Learners

    ERIC Educational Resources Information Center

    Sarani, Abdullah; Behtash, Esmail Zare; Nezhad Arani, Saieed Moslemi

    2014-01-01

    This study aims at finding the effect of video-based tasks in improving the listening comprehension ability of Iranian pre-intermediate EFL (English Foreign Language) learners. After determining the level of learners, an experimental and control group, each of 20 participants, were nominated to contribute to the study. From the time the pre-test…

  8. Reflections on Speech Motor Control Based on Phonatory and DDK Tasks in Dysarthric Subjects with Lesions in Different Cerebellar Loci

    ERIC Educational Resources Information Center

    Vandana, V. P.

    2007-01-01

    There are very few acoustic studies reflecting on the localization of speech function within the different loci of the cerebellum. Task based performance profile of subjects with lesion in different cerebellar loci is not reported. Also, the findings on nonfocal cerebellar lesions cannot be generalized to lesions restricted to the cerebellum.…

  9. Teachers' Perceptions of Task-Based Language Teaching in English Classrooms in Taiwanese Junior High Schools

    ERIC Educational Resources Information Center

    Lin, Tzu-Bin; Wu, Chiao-Wen

    2012-01-01

    After introducing new curriculum guidelines during education reform, the Taiwan Ministry of Education has taken the lead in integrating a communicative approach into the new English language curriculum. Task-based language teaching (TBLT) is viewed as a realisation of communicative language teaching and is one of the most popular English language…

  10. The Role of Time on Task in Computer-Based Low-Stakes Assessment of Cross-Curricular Skills

    ERIC Educational Resources Information Center

    Kupiainen, Sirkku; Vainikainen, Mari-Pauliina; Marjanen, Jukka; Hautamäki, Jarkko

    2014-01-01

    The role of time on task (TOT) for students' attainment in a low-stakes assessment of cross-curricular skills was examined using the log data collected in the computer-based assessment (CBA). Two structural equation models were compared: Model 1, in which students' test scores were explained by grade point average (GPA) together with mastery and…

  11. Teachers' Perceptions of Task-Based Language Teaching in English Classrooms in Taiwanese Junior High Schools

    ERIC Educational Resources Information Center

    Lin, Tzu-Bin; Wu, Chiao-Wen

    2012-01-01

    After introducing new curriculum guidelines during education reform, the Taiwan Ministry of Education has taken the lead in integrating a communicative approach into the new English language curriculum. Task-based language teaching (TBLT) is viewed as a realisation of communicative language teaching and is one of the most popular English language

  12. On the Relationship Between Effort Toward an Ongoing Task and Cue Detection in Event-Based Prospective Memory

    ERIC Educational Resources Information Center

    Marsh, Richard L.; Hicks, Jason L.; Cook, Gabriel I.

    2005-01-01

    In recent theories of event-based prospective memory, researchers have debated what degree of resources are necessary to identify a cue as related to a previously established intention. In order to simulate natural variations in attention, the authors manipulated effort toward an ongoing cognitive task in which intention-related cues were embedded…

  13. Reading Guided by Automated Graphical Representations: How Model-Based Text Visualizations Facilitate Learning in Reading Comprehension Tasks

    ERIC Educational Resources Information Center

    Pirnay-Dummer, Pablo; Ifenthaler, Dirk

    2011-01-01

    Our study integrates automated natural language-oriented assessment and analysis methodologies into feasible reading comprehension tasks. With the newly developed T-MITOCAR toolset, prose text can be automatically converted into an association net which has similarities to a concept map. The "text to graph" feature of the software is based on…

  14. Reading Guided by Automated Graphical Representations: How Model-Based Text Visualizations Facilitate Learning in Reading Comprehension Tasks

    ERIC Educational Resources Information Center

    Pirnay-Dummer, Pablo; Ifenthaler, Dirk

    2011-01-01

    Our study integrates automated natural language-oriented assessment and analysis methodologies into feasible reading comprehension tasks. With the newly developed T-MITOCAR toolset, prose text can be automatically converted into an association net which has similarities to a concept map. The "text to graph" feature of the software is based on

  15. A learning scheme for reach to grasp movements: on EMG-based interfaces using task specific motion decoding models.

    PubMed

    Liarokapis, Minas V; Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J; Manolakos, Elias S

    2013-09-01

    A learning scheme based on random forests is used to discriminate between different reach to grasp movements in 3-D space, based on the myoelectric activity of human muscles of the upper-arm and the forearm. Task specificity for motion decoding is introduced in two different levels: Subspace to move toward and object to be grasped. The discrimination between the different reach to grasp strategies is accomplished with machine learning techniques for classification. The classification decision is then used in order to trigger an EMG-based task-specific motion decoding model. Task specific models manage to outperform "general" models providing better estimation accuracy. Thus, the proposed scheme takes advantage of a framework incorporating both a classifier and a regressor that cooperate advantageously in order to split the task space. The proposed learning scheme can be easily used to a series of EMG-based interfaces that must operate in real time, providing data-driven capabilities for multiclass problems, that occur in everyday life complex environments. PMID:25055370

  16. Integrating English for Specific Purposes Courseware into Task-Based Learning in a Context of Preparing for International Trade Fairs

    ERIC Educational Resources Information Center

    Tsai, Shu-Chiao

    2013-01-01

    This study reports on integrating courseware for participating in international trade fairs into English for specific purposes (ESP) instruction at a technical university in Taiwan. An Information and Communication Technology (ICT) approach combining courseware integration with Task Based Learning (TBL), was adopted. Evaluation of implementing…

  17. Teacher- and Learner-Led Discourse in Task-Based Grammar Instruction: Providing Procedural Assistance for L2 Morphosyntactic Development

    ERIC Educational Resources Information Center

    Toth, Paul D.

    2008-01-01

    This study compares quantitative and qualitative results for task-based second language (L2) grammar instruction conducted as whole-class, teacher-led discourse (TLD) versus small-group, learner-led discourse (LLD). Participants included 78 English-speaking adults from six university classes of beginning L2 Spanish, with two assigned to each…

  18. YouTube for Two: Online Video Resources in a Student-Centered, Task-Based ESL/EFL Environment

    ERIC Educational Resources Information Center

    Hamilton, Robert

    2010-01-01

    Online technology and streaming video have the potential to generate tremendous interest and motivation in ESL/EFL students. Unfortunately, as the basis for a task-based language teaching (TBLT) program, such technology often places students in a passive position and limits inter-student communication. This paper describes a successful TBLT course…

  19. Integrating English for Specific Purposes Courseware into Task-Based Learning in a Context of Preparing for International Trade Fairs

    ERIC Educational Resources Information Center

    Tsai, Shu-Chiao

    2013-01-01

    This study reports on integrating courseware for participating in international trade fairs into English for specific purposes (ESP) instruction at a technical university in Taiwan. An Information and Communication Technology (ICT) approach combining courseware integration with Task Based Learning (TBL), was adopted. Evaluation of implementing

  20. Genre-Based Tasks in Foreign Language Writing: Developing Writers' Genre Awareness, Linguistic Knowledge, and Writing Competence

    ERIC Educational Resources Information Center

    Yasuda, Sachiko

    2011-01-01

    This study examines how novice foreign language (FL) writers develop their genre awareness, linguistic knowledge, and writing competence in a genre-based writing course that incorporates email-writing tasks. To define genre, the study draws on systemic functional linguistics (SFL) that sees language as a resource for making meaning in a particular…

  1. Presentation-Practice-Production and Task-Based Learning in the Light of Second Language Learning Theories.

    ERIC Educational Resources Information Center

    Ritchie, Graeme

    2003-01-01

    Features of presentation-practice-production (PPP) and task-based learning (TBL) models for language teaching are discussed with reference to language learning theories. Pre-selection of target structures, use of controlled repetition, and explicit grammar instruction in a PPP lesson are given. Suggests TBL approaches afford greater learning…

  2. Effects of Summary Writing on Oral Proficiency Performance within a Computer-Based Test for Integrated Listening-Speaking Tasks

    ERIC Educational Resources Information Center

    Lu, Zhihong; Wang, Yanfei

    2014-01-01

    The effective design of test items within a computer-based language test (CBLT) for developing English as a foreign language (EFL) learners' listening and speaking skills has become an increasingly challenging task for both test users and test designers compared with that of pencil-and-paper tests in the past. It needs to fit integrated oral…

  3. "Lo Cotidiano": The Effectiveness of Critical Task-Based Instruction in Teaching the Culture of Everyday Life

    ERIC Educational Resources Information Center

    García-Villada, Eduardo

    2014-01-01

    Teaching cultural competency in the language classroom can be a challenge. This study explores the effectiveness of task-based instruction (Lee, 2000) on the learning of culture by students in college-level Spanish language courses. Students were required to record oral presentations, write essays, and make comparisons between the culture and…

  4. Approximating Implicit and Explicit Mentalizing with Two Naturalistic Video-Based Tasks in Typical Development and Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Rosenblau, Gabriela; Kliemann, Dorit; Heekeren, Hauke R.; Dziobek, Isabel

    2015-01-01

    Individuals with autism spectrum disorder (ASD) have been proposed to show greater impairments in implicit than explicit mentalizing. To test this proposition, we developed two comparable naturalistic tasks for a performance-based approximation of implicit and explicit mentalizing in 28 individuals with ASD and 23 matched typically developed (TD)…

  5. Virtual Task-Based Situated Language-Learning with "Second Life": Developing EFL Pragmatic Writing and Technological Self-Efficacy

    ERIC Educational Resources Information Center

    Abdallah, Mahmoud M. S.; Mansour, Marian M.

    2015-01-01

    This paper reports on an experimental research study that aimed at investigating the effectiveness of employing a virtual task-based situated language learning (TBSLL) environment mediated by Second Life (SL) in developing EFL student teachers' pragmatic writing skills and their technological self-efficacy. To reach this goal, a control-only…

  6. Paleoglaciation of the Tibetan Plateau and surrounding mountains based on exposure ages and ELA depression estimates

    NASA Astrophysics Data System (ADS)

    Heyman, Jakob

    2014-05-01

    The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30 ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337 ± 197 m for the LGM and 494 ± 280 m for the pre-LGM indicate restricted glacier expansion.

  7. Measuring cognitive load during simulation-based psychomotor skills training: sensitivity of secondary-task performance and subjective ratings.

    PubMed

    Haji, Faizal A; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-12-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p = 0.012; SDR 0.27 vs. 0.97, p < 0.001; SRME 7.75 vs. 2.80, p < 0.001). Similarly, secondary task performance deteriorated from baseline to dual-task among novices (RRT 0.63 vs. 1.76 s, p < 0.006 and SDR 1.00 vs. 0.27, p < 0.001), but not experts (RRT 0.63 vs. 0.73 s, p = 0.124 and SDR 1.00 vs. 0.97, p = 0.178). In phase 2, novices practiced surgical knot-tying on the bench top simulator during consecutive dual-task trials. A significant increase in SDR (F(9,63) = 6.63, p < 0.001, f = 0.97) and decrease in SRME (F(9,63) = 9.39, p < 0.001, f = 1.04) was observed during simulation training, while RRT did not change significantly (F(9,63) = 1.18, p < 0.32, f = 0.41). The results suggest subjective ratings and dual-task performance can be used to track changes in CL among novices, particularly in early phases of simulation-based skills training. The implications for measuring CL in simulation instructional design research are discussed. PMID:25761454

  8. Face puzzle—two new video-based tasks for measuring explicit and implicit aspects of facial emotion recognition

    PubMed Central

    Kliemann, Dorit; Rosenblau, Gabriela; Bölte, Sven; Heekeren, Hauke R.; Dziobek, Isabel

    2013-01-01

    Recognizing others' emotional states is crucial for effective social interaction. While most facial emotion recognition tasks use explicit prompts that trigger consciously controlled processing, emotional faces are almost exclusively processed implicitly in real life. Recent attempts in social cognition suggest a dual process perspective, whereby explicit and implicit processes largely operate independently. However, due to differences in methodology the direct comparison of implicit and explicit social cognition has remained a challenge. Here, we introduce a new tool to comparably measure implicit and explicit processing aspects comprising basic and complex emotions in facial expressions. We developed two video-based tasks with similar answer formats to assess performance in respective facial emotion recognition processes: Face Puzzle, implicit and explicit. To assess the tasks' sensitivity to atypical social cognition and to infer interrelationship patterns between explicit and implicit processes in typical and atypical development, we included healthy adults (NT, n = 24) and adults with autism spectrum disorder (ASD, n = 24). Item analyses yielded good reliability of the new tasks. Group-specific results indicated sensitivity to subtle social impairments in high-functioning ASD. Correlation analyses with established implicit and explicit socio-cognitive measures were further in favor of the tasks' external validity. Between group comparisons provide first hints of differential relations between implicit and explicit aspects of facial emotion recognition processes in healthy compared to ASD participants. In addition, an increased magnitude of between group differences in the implicit task was found for a speed-accuracy composite measure. The new Face Puzzle tool thus provides two new tasks to separately assess explicit and implicit social functioning, for instance, to measure subtle impairments as well as potential improvements due to social cognitive interventions. PMID:23805122

  9. Managing CMC-Based Task through Text-Based Dialogue: An Exploratory Study in a Chinese EFL Context

    ERIC Educational Resources Information Center

    Yu, Lianfen; Zeng, Gang

    2011-01-01

    This paper examines EFL learners' dialogic interaction in the implementation of a computer-mediated communication (CMC) task. Within the framework of sociocultural theory, the research focuses on how learners working in pairs collaboratively perform task management and build relationship in the synchronous CMC context. Sixteen Chinese tertiary EFL…

  10. Implementation Approach for Plug-in Electric Vehicles at Joint Base Lewis McChord. Task 4

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2014-12-01

    This study focused on Joint Base Lewis McChord (JBLM), which is located in Washington State. Task 1 consisted of a survey of the non-tactical fleet of vehicles at JBLM to begin the review of vehicle mission assignments and the types of vehicles in service. In Task 2, daily operational characteristics of select vehicles were identified and vehicle movements were recorded in data loggers in order to characterize the vehicles’ missions. In Task 3, the results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption (i.e., whether a battery electric vehicle or plug-in hybrid electric vehicle [collectively referred to as PEVs] can fulfill the mission requirements0, as well as the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the JBLM fleet.

  11. Comparative evaluation of twenty pilot workload assessment measure using a psychomotor task in a moving base aircraft simulator

    NASA Technical Reports Server (NTRS)

    Connor, S. A.; Wierwille, W. W.

    1983-01-01

    A comparison of the sensitivity and intrusion of twenty pilot workload assessment techniques was conducted using a psychomotor loading task in a three degree of freedom moving base aircraft simulator. The twenty techniques included opinion measures, spare mental capacity measures, physiological measures, eye behavior measures, and primary task performance measures. The primary task was an instrument landing system (ILS) approach and landing. All measures were recorded between the outer marker and the middle marker on the approach. Three levels (low, medium, and high) of psychomotor load were obtained by the combined manipulation of windgust disturbance level and simulated aircraft pitch stability. Six instrument rated pilots participated in four seasons lasting approximately three hours each.

  12. Task-based performance analysis of SART for digital breast tomosynthesis using signal CNR and channelised Hotelling observers

    NASA Astrophysics Data System (ADS)

    Van de Sompel, Dominique; Brady, Michael; Ho, Candy P. S.; McLennan, Andrew

    2010-04-01

    In this study, we examine the performance of the simultaneous algebraic reconstruction technique (SART) for digital breast tomosynthesis under variations in key imaging parameters, such as the number of iterations, number of projections, angular range, initial guess, radiation dose, etc. We use a real breast CT volume as a ground truth digital phantom from which to simulate x-ray projections under the various selected conditions. The reconstructed image quality is measured using task-based metrics, namely signal CNR and the AUC of a Channelised Hotelling Observer with Laguerre-Gauss basis functions. The task at hand is a signal-known-exactly (SKE) task, where the objective is to detect a simulated mass inserted into the breast CT volume.

  13. Cooperative scheduling of imaging observation tasks for high-altitude airships based on propagation algorithm.

    PubMed

    Chuan, He; Dishan, Qiu; Jin, Liu

    2012-01-01

    The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA). Then, a novel swarm intelligence algorithm named propagation algorithm (PA) is combined with the key node search algorithm (KNSA) to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible. PMID:23365522

  14. Reversal Learning Task in Children with Autism Spectrum Disorder: A Robot-Based Approach.

    PubMed

    Costescu, Cristina A; Vanderborght, Bram; David, Daniel O

    2015-11-01

    Children with autism spectrum disorder (ASD) engage in highly perseverative and inflexible behaviours. Technological tools, such as robots, received increased attention as social reinforces and/or assisting tools for improving the performance of children with ASD. The aim of our study is to investigate the role of the robotic toy Keepon in a cognitive flexibility task performed by children with ASD and typically developing (TD) children. The number of participants included in this study is 81 children: 40 TD children and 41 children with ASD. Each participant had to go through two conditions: robot interaction and human interaction in which they had performed the reversal learning task. Our primary outcomes are the number of errors from acquisition phase and from reversal phase of the task; as secondary outcomes we have measured attentional engagement and positive affect. The results of this study showed that children with ASD are more engaged in the task and they seem to enjoy more the task when interacting with the robot compared with the interaction with the adult. On the other hand their cognitive flexibility performance is, in general, similar in the robot and the human conditions with the exception of the learning phase where the robot can interfere with the performance. Implication for future research and practice are discussed. PMID:25479815

  15. Cooperative Scheduling of Imaging Observation Tasks for High-Altitude Airships Based on Propagation Algorithm

    PubMed Central

    Chuan, He; Dishan, Qiu; Jin, Liu

    2012-01-01

    The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA). Then, a novel swarm intelligence algorithm named propagation algorithm (PA) is combined with the key node search algorithm (KNSA) to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible. PMID:23365522

  16. The Intersection of Task-Based Interaction, Task Complexity, and Working Memory: L2 Question Development through Recasts in a Laboratory Setting

    ERIC Educational Resources Information Center

    Kim, YouJin; Payant, Caroline; Pearson, Pamela

    2015-01-01

    The extent to which individual differences in cognitive abilities affect the relationship among task complexity, attention to form, and second language development has been addressed only minimally in the cognition hypothesis literature. The present study explores how reasoning demands in tasks and working memory (WM) capacity predict learners'…

  17. Is there phonologically based priming in the same-different task? Evidence from Japanese-English bilinguals.

    PubMed

    Lupker, Stephen J; Nakayama, Mariko; Perea, Manuel

    2015-10-01

    Norris and colleagues (Kinoshita & Norris, 2009; Norris & Kinoshita, 2008; Norris, Kinoshita, & van Casteren, 2010) have suggested that priming effects in the masked prime same-different task are based solely on prelexical orthographic codes. This suggestion was evaluated by examining phonological priming in that task using Japanese-English bilinguals. Targets and reference words were English words with the primes written in Katakana script, a syllabic script that is orthographically quite different from the Roman letter script used in writing English. Phonological priming was observed both when the primes were Japanese cognate translation equivalents of the English target/reference words (Experiment 1) and when the primes were phonologically similar Katakana nonwords (Experiment 2), with the former effects being substantially larger than the noncognate translation priming effects reported by Lupker, Perea, and Nakayama (2015). These results indicate that the same-different task is influenced by phonological information. One implication is that, due to the fact that phonology and orthography are inevitably confounded in Roman letter languages, previously reported priming effects in those languages may have been at least partly due to phonological, rather than orthographic, similarity. The potential extent of this problem, the nature of the matching process in the same-different task, and the implications for using this task as a means of investigating the orthographic code in reading are discussed. PMID:26076173

  18. Epidemic Spreading in Contact Networks Based on Exposure Level

    NASA Astrophysics Data System (ADS)

    Duan, Wen-Qi; Chen, Zhong; Liu, Zeng-Rong

    2006-05-01

    Most epidemic models for the spread of diseases in contact networks take the assumption of the infected probability of a susceptible agent dependent on its absolute number of infectious neighbours. We introduce a new epidemic model in which the infected probability of a susceptible agent in contact networks depends not on its degree but on its exposure level. We find that effective average infection rate bar lambda (i.e., the average number of infections produced by a single contact between infected individuals and susceptible individuals) has an epidemic threshold bar lambdac = 1, which is related to recovery rate, epidemic mechanisms and topology of contact network. Furthermore, we show the dominating importance of epidemic mechanisms in determining epidemic patterns and discussed the implications of our model for infection control policy.

  19. Predicting Lactational and Early Post-Weaning Exposures in Rats Using Biologically Based Pharmacokinetic Modeling

    EPA Science Inventory

    Risk and safety assessments for early life exposures to environmental chemicals or pharmaceuticals based on cross-species extrapolation would greatly benefit from information on chemical dosimetry in the young.

  20. Feasibility of performing space surveillance tasks with a proposed space-based optical architecture

    NASA Astrophysics Data System (ADS)

    Flohrer, Tim; Krag, Holger; Klinkrad, Heiner; Schildknecht, Thomas

    Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO instrumentation was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive op-tical instrument. SBO was requested to provide statistical information on the space debris population, in terms of number of objects and size distribution. The SBO was considered to be a cost-efficient instrumentation of 20 cm aperture and 6 deg field-of-view with flexible integration requirements. It should be possible to integrate the SBO easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. It was shown in the performance analysis that the statistical information on small-sized space debris can only be collected if the observation ranges are comparatively small. Two of the most promising concepts were to observe objects in LEO from a sensor placed into a sun-synchronous LEO, while objects in GEO should be observed from a GEO satellite. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are stud-ied for the build-up and to maintenance of a catalogue of objects. In this paper we analyse how the SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of objects at higher altitude, such as GEO and Medium-Earth Orbits (MEO). Of particular interest are the radiometric performance from which we derive the detectable object diameters, the coverage of a reference population, and the covered arc lengths of individual objects. The latter is of particular interest for the simu-lation of the orbit determination, correlation, and cataloguing. Assuming realistic noise levels known from the SBO design we simulate first orbit determination of unknown objects (surveys) and orbit improvements (tracking) for sample objects. We use a simulation environment that comprises the ESA Program for Radar and Optical Observation Forecasting (PROOF) in the version 2005 and AIUB's program system CelMech. ESA's MASTER-2005 serves as reference population for all analyses.

  1. Exposure assessment of mobile phone base station radiation in an outdoor environment using sequential surrogate modeling.

    PubMed

    Aerts, Sam; Deschrijver, Dirk; Joseph, Wout; Verloock, Leen; Goeminne, Francis; Martens, Luc; Dhaene, Tom

    2013-05-01

    Human exposure to background radiofrequency electromagnetic fields (RF-EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF-EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04 km(2) for Global System for Mobile Communications (GSM) technology at 900 MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling. PMID:23315952

  2. Assessment of the dose reduction potential of a model-based iterative reconstruction algorithm using a task-based performance metrology

    SciTech Connect

    Samei, Ehsan; Richard, Samuel

    2015-01-15

    Purpose: Different computed tomography (CT) reconstruction techniques offer different image quality attributes of resolution and noise, challenging the ability to compare their dose reduction potential against each other. The purpose of this study was to evaluate and compare the task-based imaging performance of CT systems to enable the assessment of the dose performance of a model-based iterative reconstruction (MBIR) to that of an adaptive statistical iterative reconstruction (ASIR) and a filtered back projection (FBP) technique. Methods: The ACR CT phantom (model 464) was imaged across a wide range of mA setting on a 64-slice CT scanner (GE Discovery CT750 HD, Waukesha, WI). Based on previous work, the resolution was evaluated in terms of a task-based modulation transfer function (MTF) using a circular-edge technique and images from the contrast inserts located in the ACR phantom. Noise performance was assessed in terms of the noise-power spectrum (NPS) measured from the uniform section of the phantom. The task-based MTF and NPS were combined with a task function to yield a task-based estimate of imaging performance, the detectability index (d′). The detectability index was computed as a function of dose for two imaging tasks corresponding to the detection of a relatively small and a relatively large feature (1.5 and 25 mm, respectively). The performance of MBIR in terms of the d′ was compared with that of ASIR and FBP to assess its dose reduction potential. Results: Results indicated that MBIR exhibits a variability spatial resolution with respect to object contrast and noise while significantly reducing image noise. The NPS measurements for MBIR indicated a noise texture with a low-pass quality compared to the typical midpass noise found in FBP-based CT images. At comparable dose, the d′ for MBIR was higher than those of FBP and ASIR by at least 61% and 19% for the small feature and the large feature tasks, respectively. Compared to FBP and ASIR, MBIR indicated a 46%–84% dose reduction potential, depending on task, without compromising the modeled detection performance. Conclusions: The presented methodology based on ACR phantom measurements extends current possibilities for the assessment of CT image quality under the complex resolution and noise characteristics exhibited with statistical and iterative reconstruction algorithms. The findings further suggest that MBIR can potentially make better use of the projections data to reduce CT dose by approximately a factor of 2. Alternatively, if the dose held unchanged, it can improve image quality by different levels for different tasks.

  3. Classroom-Based Functional Analysis and Intervention for Disruptive and Off-Task Behaviors

    ERIC Educational Resources Information Center

    Shumate, Emily D.; Wills, Howard P.

    2010-01-01

    Although there is a growing body of literature on the use of functional analysis in schools, there is a need for more demonstrations of this technology being used during the course of typical instruction. In this study, we conducted functional analyses of disruptive and off-task behavior in a reading classroom setting for 3 participants of typical…

  4. Virtual reality-based navigation task to reveal obstacle avoidance performance in individuals with visuospatial neglect.

    PubMed

    Aravind, Gayatri; Darekar, Anuja; Fung, Joyce; Lamontagne, Anouk

    2015-03-01

    Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30 (°) contralesionally/ipsilesionally. Our results indicate that in the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. We conclusion the observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alter obstacle avoidance abilities. PMID:25420267

  5. Developing Classroom Assessment Tasks Based on a Language Arts Curriculum: An In-service Approach.

    ERIC Educational Resources Information Center

    Patelis, Thanos; Singer, Judith

    The purpose of this study was twofold: to develop teachers' assessment skills and to enable teachers to apply this knowledge to the creation of assessment tasks for the language arts curriculum thereby linking curriculum to assessment. Using a newly developed language arts curriculum, 79 urban Connecticut teachers were asked to develop the…

  6. Humans and Monkeys Exert Metacognitive Control Based on Learning Difficulty in a Perceptual Categorization Task

    ERIC Educational Resources Information Center

    Redford, Joshua S.

    2010-01-01

    Recently, Redford (2010) found that monkeys seemed to exert metacognitive control in a category-learning paradigm. Specifically, they selected more trials to view as the difficulty of the category-learning task increased. However, category-learning difficulty was determined by manipulating the family resemblance across the to-be-learned exemplars.…

  7. Talking, Tuning in and Noticing: Exploring the Benefits of Output in Task-Based Peer Interaction

    ERIC Educational Resources Information Center

    Philp, Jenefer; Iwashita, Noriko

    2013-01-01

    This study examines whether the process of interacting in a second language, versus observing others interact, may differentially affect learner's awareness of language. This study involved 26 university students of intermediate-level French. Two experimental groups, Interactors and Observers, engaged in three sessions of dyadic task-based…

  8. An Exploratory Study of Collocational Use by ESL Students--A Task Based Approach

    ERIC Educational Resources Information Center

    Fan, May

    2009-01-01

    Collocation is an aspect of language generally considered arbitrary by nature and problematic to L2 learners who need collocational competence for effective communication. This study attempts, from the perspective of L2 learners, to have a deeper understanding of collocational use and some of the problems involved, by adopting a task based…

  9. Storyboarding: A Method for Bootstrapping the Design of Computer-Based Educational Tasks

    ERIC Educational Resources Information Center

    Jones, Ian

    2008-01-01

    There has been a recent call for the use of more systematic thought experiments when investigating learning. This paper presents a storyboarding method for capturing and sharing initial ideas and their evolution in the design of a mathematics learning task. The storyboards produced can be considered as "virtual data" created by thought experiments

  10. Temporal Effects of Alignment in Text-Based, Task-Oriented Discourse

    ERIC Educational Resources Information Center

    Foltz, Anouschka; Gaspers, Judith; Meyer, Carolin; Thiele, Kristina; Cimiano, Philipp; Stenneken, Prisca

    2015-01-01

    Communicative alignment refers to adaptation to one's communication partner. Temporal aspects of such alignment have been little explored. This article examines temporal aspects of lexical and syntactic alignment (i.e., tendencies to use the interlocutor's lexical items and syntactic structures) in task-oriented discourse. In particular, we

  11. Winning or Losing against an Opposite-Sex Peer on a Gender-Based Competitive Task.

    ERIC Educational Resources Information Center

    Gilbert, Stefanie; Thompson, J. Kevin

    1999-01-01

    Explored the effects on college students' mood and body image of a negative versus positive outcome in an opposite-sex, competitive peer interaction. Used one gender-neutral and one gender stereotypical task. There were no gender differences in reactions to winning or losing gender-neutral competitions, except marginally for depression. The…

  12. Proposal of Constraints Analysis Method Based on Network Model for Task Planning

    NASA Astrophysics Data System (ADS)

    Tomiyama, Tomoe; Sato, Tatsuhiro; Morita, Toyohisa; Sasaki, Toshiro

    Deregulation has been accelerating several activities toward reengineering business processes, such as railway through service and modal shift in logistics. Making those activities successful, business entities have to regulate new business rules or know-how (we call them ‘constraints’). According to the new constraints, they need to manage business resources such as instruments, materials, workers and so on. In this paper, we propose a constraint analysis method to define constraints for task planning of the new business processes. To visualize each constraint's influence on planning, we propose a network model which represents allocation relations between tasks and resources. The network can also represent task ordering relations and resource grouping relations. The proposed method formalizes the way of defining constraints manually as repeatedly checking the network structure and finding conflicts between constraints. Being applied to crew scheduling problems shows that the method can adequately represent and define constraints of some task planning problems with the following fundamental features, (1) specifying work pattern to some resources, (2) restricting the number of resources for some works, (3) requiring multiple resources for some works, (4) prior allocation of some resources to some works and (5) considering the workload balance between resources.

  13. Learning Effects in the Block Design Task: A Stimulus Parameter-Based Approach

    ERIC Educational Resources Information Center

    Miller, Joseph C.; Ruthig, Joelle C.; Bradley, April R.; Wise, Richard A.; Pedersen, Heather A.; Ellison, Jo M.

    2009-01-01

    Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U,…

  14. Classroom-Based Functional Analysis and Intervention for Disruptive and Off-Task Behaviors

    ERIC Educational Resources Information Center

    Shumate, Emily D.; Wills, Howard P.

    2010-01-01

    Although there is a growing body of literature on the use of functional analysis in schools, there is a need for more demonstrations of this technology being used during the course of typical instruction. In this study, we conducted functional analyses of disruptive and off-task behavior in a reading classroom setting for 3 participants of typical

  15. Text, Graphics, and Multimedia Materials Employed in Learning a Computer-Based Procedural Task

    ERIC Educational Resources Information Center

    Coffindaffer, Kari Christine Carlson

    2010-01-01

    The present research study investigated the interaction of graphic design students with different forms of software training materials. Four versions of the procedural task instructions were developed (A) Traditional Textbook with Still Images, (B) Modified Text with Integrated Still Images, (C) Onscreen Modified Text with Silent Onscreen Video…

  16. An accelerometer-based method for estimating fluidity in the sit-to-walk task.

    PubMed

    Asakura, Tomoyuki; Hagiwara, Hikaru; Miyazawa, Yoshiyuki; Usuda, Shigeru

    2015-11-01

    [Purpose] The purpose of this study was to clarify the validity of accelerometer data for quantifying fluidity during the sit-to-walk task. [Subjects] The participants were 16 healthy young males. [Methods] The timing of events (task onset, maximum trunk inclination, and first heel strike) was determined from the acceleration waveform and compared to the timing determined from a three-dimensional motion analysis (task onset, maximum trunk inclination) or foot pressure sensor data (first heel strike). Regression analysis was used to estimate the fluidity index (FI) from the duration between events and the magnitude of the acceleration peak. The task was performed at two speeds (comfortable and maximum). [Results] A comparison of the timings from two different systems indicated no systematic bias. Specific events could be identified from acceleration data using regression analysis under both speed conditions. In addition, significant regression equations predictive of FI were constructed using the duration between events under both speed conditions. The duration from the maximum trunk inclination to the first heel strike was the best predictor of FI. [Conclusion] Accelerometer data may be used to precisely and conveniently evaluate fluidity. The clinical utility of these data should be tested in elderly individuals or patient populations. PMID:26696739

  17. A survey and task-based quality assessment of static 2D colormaps

    NASA Astrophysics Data System (ADS)

    Bernard, Jürgen; Steiger, Martin; Mittelstädt, Sebastian; Thum, Simon; Keim, Daniel; Kohlhammer, Jörn

    2015-01-01

    Color is one of the most important visual variables since it can be combined with any other visual mapping to encode information without using additional space on the display. Encoding one or two dimensions with color is widely explored and discussed in the field. Also mapping multi-dimensional data to color is applied in a vast number of applications, either to indicate similar, or to discriminate between different elements or (multi-dimensional) structures on the screen. A variety of 2D colormaps exists in literature, covering a large variance with respect to different perceptual aspects. Many of the colormaps have a different perspective on the underlying data structure as a consequence of the various analysis tasks that exist for multivariate data. Thus, a large design space for 2D colormaps exists which makes the development and use of 2D colormaps cumbersome. According to our literature research, 2D colormaps have not been subject of in-depth quality assessment. Therefore, we present a survey of static 2D colormaps as applied for information visualization and related fields. In addition, we map seven devised quality assessment measures for 2D colormaps to seven relevant tasks for multivariate data analysis. Finally, we present the quality assessment results of the 2D colormaps with respect to the seven analysis tasks, and contribute guidelines about which colormaps to select or create for each analysis task.

  18. An accelerometer-based method for estimating fluidity in the sit-to-walk task

    PubMed Central

    Asakura, Tomoyuki; Hagiwara, Hikaru; Miyazawa, Yoshiyuki; Usuda, Shigeru

    2015-01-01

    [Purpose] The purpose of this study was to clarify the validity of accelerometer data for quantifying fluidity during the sit-to-walk task. [Subjects] The participants were 16 healthy young males. [Methods] The timing of events (task onset, maximum trunk inclination, and first heel strike) was determined from the acceleration waveform and compared to the timing determined from a three-dimensional motion analysis (task onset, maximum trunk inclination) or foot pressure sensor data (first heel strike). Regression analysis was used to estimate the fluidity index (FI) from the duration between events and the magnitude of the acceleration peak. The task was performed at two speeds (comfortable and maximum). [Results] A comparison of the timings from two different systems indicated no systematic bias. Specific events could be identified from acceleration data using regression analysis under both speed conditions. In addition, significant regression equations predictive of FI were constructed using the duration between events under both speed conditions. The duration from the maximum trunk inclination to the first heel strike was the best predictor of FI. [Conclusion] Accelerometer data may be used to precisely and conveniently evaluate fluidity. The clinical utility of these data should be tested in elderly individuals or patient populations. PMID:26696739

  19. Conflict tasks and the diffusion framework: Insight in model constraints based on psychological laws.

    PubMed

    Servant, Mathieu; Montagnini, Anna; Burle, Borís

    2014-07-01

    Formal models of decision-making have traditionally focused on simple, two-choice perceptual decisions. To date, one of the most influential account of this process is Ratcliff's drift diffusion model (DDM). However, the extension of the model to more complex decisions is not straightforward. In particular, conflicting situations, such as the Eriksen, Stroop, or Simon tasks, require control mechanisms that shield the cognitive system against distracting information. We adopted a novel strategy to constrain response time (RT) models by concurrently investigating two well-known empirical laws in conflict tasks, both at experimental and modeling levels. The two laws, predicted by the DDM, describe the relationship between mean RT and (i) target intensity (Piéron's law), (ii) standard deviation of RT (Wagenmakers-Brown's law). Pioneering work has shown that Piéron's law holds in the Stroop task, and has highlighted an additive relationship between target intensity and compatibility. We found similar results in both Eriksen and Simon tasks. Compatibility also violated Wagenmakers-Brown's law in a very similar and particular fashion in the two tasks, suggesting a common model framework. To investigate the nature of this commonality, predictions of two recent extensions of the DDM that incorporate selective attention mechanisms were simulated and compared to the experimental results. Both models predict Piéron's law and the violation of Wagenmakers-Brown's law by compatibility. Fits of the models to the RT distributions and accuracy data allowed us to further reveal their relative strengths and deficiencies. Combining experimental and computational results, this study sets the groundwork for a unified model of decision-making in conflicting environments. PMID:24762975

  20. An integrated exposure assessment of phthalates for the general population in China based on both exposure scenario and biomonitoring estimation approaches.

    PubMed

    Cao, Yan; Liu, Jianguo; Liu, Yang; Wang, Jie; Hao, Xuewen

    2016-02-01

    The representativeness of available studies on integrated exposure assessment of phthalates for the general population in China is lacking. Based on an exhaustive review of the extensive monitoring data available for China, this study presents a large-scale estimation of exposure levels to three typical phthalates, di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP) and diisobutyl phthalate (DiBP), by applying both exposure scenario and biomonitoring estimation approaches. The respective median exposure levels from the exposure scenario and biomonitoring estimation approaches were 3.80, 3.02 and 1.00 μg/kg bw/day and 3.38, 3.21 and 3.32 μg/kg bw/day for DEHP, DBP and DiBP, which are acceptable levels of exposure with respect to current international guidelines. Evaluation results from the two approaches showed both similarities and differences among the different phthalates, making the exposure assessment comparable and more comprehensive. In terms of sources of exposure, food intake was the largest contributor, while indoor air exposure had greater contribution to the estimated daily intakes (EDIs) of DiBP than that of the other phthalates. Moreover, more attention should be paid to the higher exposure levels of phthalates in several intensively industrialized and urbanized areas, and the causes of the different exposure levels in the different regions need to be further explored. PMID:26654930

  1. Assessment of Charging Infrastructure for Plug-in Electric Vehicles at Marine Corps Base Camp Lejeune. Task 3

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for the U.S. Department of Energy’s advanced vehicle testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense-based studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 consisted of a survey of the non-tactical fleet of vehicles at Marine Corps Base Camp Lejeune to begin the review of vehicle mission assignments and types of vehicles in service. Task 2 selected vehicles for further monitoring and involved identifying daily operational characteristics of these select vehicles. Data logging of vehicle movements was initiated in order to characterize the vehicle’s mission. The Task 3 vehicle utilization report provided results of the data analysis and observations related to the replacement of current vehicles with PEVs. Finally, this report provides an assessment of charging infrastructure required to support the suggested PEV replacements. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune Fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from Marine Corps Base Camp Lejeune personnel.

  2. Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan.

    PubMed

    Lipp, Ilona; Murphy, Kevin; Caseras, Xavier; Wise, Richard G

    2015-06-01

    FMRI BOLD responses to changes in neural activity are influenced by the reactivity of the vasculature. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan. This study aimed to compare three breath-hold based analysis approaches (block design, sine-cosine regressor and CO2 regressor) and a resting state approach (CO2 regressor) to measure vascular reactivity. We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Vascular reactivity was defined as CO2-related BOLD percent signal change/mmHg change in CO2. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity. We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment. PMID:25795342

  3. Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan

    PubMed Central

    Lipp, Ilona; Murphy, Kevin; Caseras, Xavier; Wise, Richard G.

    2015-01-01

    FMRI BOLD responses to changes in neural activity are influenced by the reactivity of the vasculature. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan. This study aimed to compare three breath-hold based analysis approaches (block design, sine–cosine regressor and CO2 regressor) and a resting state approach (CO2 regressor) to measure vascular reactivity. We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Vascular reactivity was defined as CO2-related BOLD percent signal change/mm Hg change in CO2. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity. We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment. PMID:25795342

  4. Biomarker-Based Calibration of Retrospective Exposure Predictions of Perfluorooctanoic Acid

    PubMed Central

    2015-01-01

    Estimated historical exposures and serum concentrations of perfluorooctanoic acid (PFOA) have been extensively used in epidemiologic studies that examined associations between PFOA exposures and adverse health outcomes among residents in highly exposed areas in the Mid-Ohio Valley. Using measured serum PFOA levels in 2005–2006, we applied two calibration methods to these retrospective exposure predictions: (1) multiplicative calibration and (2) Bayesian pharmacokinetic calibration with larger adjustments to more recent exposure estimates and smaller adjustments to exposure estimates for years farther in the past. We conducted simulation studies of various hypothetical exposure scenarios and compared hypothetical true historical intake rates with estimates based on mis-specified baseline exposure and pharmacokinetic models to find the method with the least bias. The Bayesian method outperformed the multiplicative method if a change to bottled water consumption was not reported or if the half-life of PFOA was mis-specified. On the other hand, the multiplicative method outperformed the Bayesian method if actual tap water consumption rates were systematically overestimated. If tap water consumption rates gradually decreased over time because of substitution with bottled water or other liquids, neither method clearly outperformed another. Calibration of retrospective exposure estimates using recently collected biomarkers may help reduce uncertainties in environmental epidemiologic studies. PMID:24730513

  5. Urine metabolite analysis as a function of deoxynivalenol exposure: an NMR-based metabolomics investigation.

    PubMed

    Hopton, R P; Turner, E; Burley, V J; Turner, P C; Fisher, J

    2010-02-01

    Deoxynivalenol (DON) is a toxic fungal metabolite that frequently contaminates cereal crops including wheat, maize and barley. Despite knowledge of frequent exposure through diet, our understanding of the potential consequences of human exposure remains limited, in part due to the lack of validated exposure biomarkers. In this study, we interrogated the urinary metabolome using nuclear magnetic resonance (NMR) spectroscopy to compare individuals with known low and high DON exposure through consumption of their normal diet. Urine samples from 22 adults from the UK (seven males, 15 females; age range = 21-59 years) had previously determined urinary DON levels using an established liquid chromatography-mass spectrometry (LC-MS) assay. Urine samples were subsequently analysed using an NMR-based metabolomics approach coupled with multivariate statistical analysis. Metabolic profiling suggested that hippurate levels could be used to distinguish between groups with low (3.6 ng DON mg(-1) creatinine: 95% CI = 2.6, 5.0 ng mg(-1)) and high (11.1 ng mg(-1): 95% CI = 8.1, 15.5 ng mg(-1)) DON exposure, with the concentration of hippurate being significantly (1.5 times) higher for people with high DON exposure than for those with low DON exposure (p = 0.047). This, to our knowledge, is the first report of a metabolomics-derived biomarker of DON exposure in humans. PMID:20013448

  6. Biomarker-based calibration of retrospective exposure predictions of perfluorooctanoic acid.

    PubMed

    Shin, Hyeong-Moo; Steenland, Kyle; Ryan, P Barry; Vieira, Verónica M; Bartell, Scott M

    2014-05-20

    Estimated historical exposures and serum concentrations of perfluorooctanoic acid (PFOA) have been extensively used in epidemiologic studies that examined associations between PFOA exposures and adverse health outcomes among residents in highly exposed areas in the Mid-Ohio Valley. Using measured serum PFOA levels in 2005-2006, we applied two calibration methods to these retrospective exposure predictions: (1) multiplicative calibration and (2) Bayesian pharmacokinetic calibration with larger adjustments to more recent exposure estimates and smaller adjustments to exposure estimates for years farther in the past. We conducted simulation studies of various hypothetical exposure scenarios and compared hypothetical true historical intake rates with estimates based on mis-specified baseline exposure and pharmacokinetic models to find the method with the least bias. The Bayesian method outperformed the multiplicative method if a change to bottled water consumption was not reported or if the half-life of PFOA was mis-specified. On the other hand, the multiplicative method outperformed the Bayesian method if actual tap water consumption rates were systematically overestimated. If tap water consumption rates gradually decreased over time because of substitution with bottled water or other liquids, neither method clearly outperformed another. Calibration of retrospective exposure estimates using recently collected biomarkers may help reduce uncertainties in environmental epidemiologic studies. PMID:24730513

  7. A Task Plan Method for Auto-Cataloguing Based on SSPAR

    NASA Astrophysics Data System (ADS)

    Zhang, Lefeng; Wu, Jianhui; Huang, Jian; Hu, Weidong

    2013-08-01

    The on-orbit object auto-cataloguing of Space Surveillance Phased Array Radar (SSPAR) contains two progresses, one is catalogue improvement, the other one is catalogue maintenance. In the catalogue improvement, SSPAR captures the new on-orbit objects in the search fence, and grows the record count of the catalogue database. In the catalogue maintenance, SSPAR samples the catalogued objects' arcs and updates their stable orbital elements. The auto-cataloguing capacity of SSPAR is highly dependent on the stable tracking and updating rate, which will be influenced by many radar parameters. If SSPAR's total time resource is allocated rationally between the searching task and tracking task according to SSPAR's work parameters and objects' orbital characteristics, SSPAR's auto-cataloguing capacity will be improved remarkably.

  8. Toward development of a two-state brain-computer interface based on mental tasks

    NASA Astrophysics Data System (ADS)

    Faradji, Farhad; Ward, Rabab K.; Birch, Gary E.

    2011-08-01

    A recently collected EEG dataset is analyzed and processed in order to evaluate the performance of a previously designed brain-computer interface (BCI) system. The EEG signals are collected from 29 channels distributed over the scalp. Four subjects completed three sessions each by performing four different mental tasks during each session. The BCI is designed in such a way that only one of the mental tasks can activate it. One important advantage of this BCI is its simplicity, since autoregressive modeling and quadratic discriminant analysis are used for feature extraction and classification, respectively. The autoregressive order which yields the best overall performance is obtained during a fivefold nested cross-validation process. The results are promising as the false positive rates are zero while the true positive rates are sufficiently high (67.26% average).

  9. The Harvard Automated Phone Task: new performance-based activities of daily living tests for early Alzheimer’s disease

    PubMed Central

    Marshall, Gad A.; Dekhtyar, Maria; Bruno, Jonathan M.; Jethwani, Kamal; Amariglio, Rebecca E.; Johnson, Keith A.; Sperling, Reisa A.; Rentz, Dorene M.

    2015-01-01

    Background Impairment in activities of daily living is a major burden for Alzheimer’s disease dementia patients and caregivers. Multiple subjective scales and a few performance-based instruments have been validated and proven to be reliable in measuring instrumental activities of daily living in Alzheimer’s disease dementia but less so in amnestic mild cognitive impairment and preclinical Alzheimer’s disease. Objective To validate the Harvard Automated Phone Task, a new performance-based activities of daily living test for early Alzheimer’s disease, which assesses high level tasks that challenge seniors in daily life. Design In a cross-sectional study, the Harvard Automated Phone Task was associated with demographics and cognitive measures through univariate and multivariate analyses; ability to discriminate across diagnostic groups was assessed; test-retest reliability with the same and alternate versions was assessed in a subset of participants; and the relationship with regional cortical thickness was assessed in a subset of participants. Setting Academic clinical research center. Participants One hundred and eighty two participants were recruited from the community (127 clinically normal elderly and 45 young normal participants) and memory disorders clinics at Brigham and Women’s Hospital and Massachusetts General Hospital (10 participants with mild cognitive impairment). Measurements As part of the Harvard Automated Phone Task, participants navigated an interactive voice response system to refill a prescription (APT-Script), select a new primary care physician (APT-PCP), and make a bank account transfer and payment (APT-Bank). The 3 tasks were scored based on time, errors, and repetitions from which composite z-scores were derived, as well as a separate report of correct completion of the task. Results We found that the Harvard Automated Phone Task discriminated well between diagnostic groups (APT-Script: p=0.002; APT-PCP: p<0.001; APT-Bank: p=0.02), had an incremental level of difficulty, and had excellent test-retest reliability (Cronbach’s α values of 0.81 to 0.87). Within the clinically normal elderly, there were significant associations in multivariate models between performance on the Harvard Automated Phone Task and executive function (APT-PCP: p<0.001), processing speed (APT-Script: p=0.005), and regional cortical atrophy (APT-PCP: p=0.001; no significant association with APT-Script) independent of hearing acuity, motor speed, age, race, education, and premorbid intelligence. Conclusions Our initial experience with the Harvard Automated Phone Task, which consists of ecologically valid, easily-administered measures of daily activities, suggests that these tasks could be useful for screening and tracking the earliest functional alterations in preclinical and early prodromal AD. PMID:26665121

  10. Computational models of upper-limb motion during functional reaching tasks for application in FES-based stroke rehabilitation.

    PubMed

    Freeman, Chris; Exell, Tim; Meadmore, Katie; Hallewell, Emma; Hughes, Ann-Marie

    2015-06-01

    Functional electrical stimulation (FES) has been shown to be an effective approach to upper-limb stroke rehabilitation, where it is used to assist arm and shoulder motion. Model-based FES controllers have recently confirmed significant potential to improve accuracy of functional reaching tasks, but they typically require a reference trajectory to track. Few upper-limb FES control schemes embed a computational model of the task; however, this is critical to ensure the controller reinforces the intended movement with high accuracy. This paper derives computational motor control models of functional tasks that can be directly embedded in real-time FES control schemes, removing the need for a predefined reference trajectory. Dynamic models of the electrically stimulated arm are first derived, and constrained optimisation problems are formulated to encapsulate common activities of daily living. These are solved using iterative algorithms, and results are compared with kinematic data from 12 subjects and found to fit closely (mean fitting between 63.2% and 84.0%). The optimisation is performed iteratively using kinematic variables and hence can be transformed into an iterative learning control algorithm by replacing simulation signals with experimental data. The approach is therefore capable of controlling FES in real time to assist tasks in a manner corresponding to unimpaired natural movement. By ensuring that assistance is aligned with voluntary intention, the controller hence maximises the potential effectiveness of future stroke rehabilitation trials. PMID:25355246

  11. Task-based vehicle interior layout design using optimization method to enhance safety

    NASA Astrophysics Data System (ADS)

    Kim, Joo; Yang, Jingzhou; Abdel-Malek, Karim; Nebel, Kyle

    2005-05-01

    This paper presents a virtual environment for conducting vehicle interior layout design. A virtual human called Santos that is biomechanically correct, has realistic musculoskeletal system, and natural motion/posture is created to live in this virtual world. One of the objectives of this virtual environment is to allow Santos to explore the interior package design such that one designs new defense and security vehicles without having to create a physical prototype to enhance safety, save time and cost. Different controls require different tasks, for example, pulling a clutch lever, pushing a button, turning a knob, and so on. Therefore, different tasks correspond to different human upper-body motions and hand loads, which in turn correspond to different displacement and torque at each joint. This is a dynamics problem for interior layout design with external loads. The formulation of dynamic equations of motion is implemented within optimization algorithm to predict joint profiles. This methodology allows Santos to help vehicle interior layout design while executing various tasks.

  12. Neglect and Motion Stimuli – Insights from a Touchscreen-Based Cancellation Task

    PubMed Central

    Cazzoli, Dario; Gutbrod, Klemens; Laube-Rosenpflanzer, Annett; Chechlacz, Magdalena; Nef, Tobias; Mosimann, Urs; Bohlhalter, Stephan; Müri, René M.; Nyffeler, Thomas

    2015-01-01

    Background and Purpose In stroke patients, neglect diagnostic is often performed by means of paper-pencil cancellation tasks. These tasks entail static stimuli, and provide no information concerning possible changes in the severity of neglect symptoms when patients are confronted with motion. We therefore aimed to directly contrast the cancellation behaviour of neglect patients under static and dynamic conditions. Since visual field deficits often occur in neglect patients, we analysed whether the integrity of the optic radiation would influence cancellation behaviour. Methods Twenty-five patients with left spatial neglect after right-hemispheric stroke were tested with a touchscreen cancellation task, once when the evenly distributed targets were stationary, and once when the identic targets moved with constant speed on a random path. The integrity of the right optic radiation was analysed by means of a hodologic probabilistic approach. Results Motion influenced the cancellation behaviour of neglect patients, and the direction of this influence (i.e., an increase or decrease of neglect severity) was modulated by the integrity of the right optic radiation. In patients with an intact optic radiation, the severity of neglect significantly decreased in the dynamic condition. Conversely, in patients with damage to the optic radiation, the severity of neglect significantly increased in the dynamic condition. Conclusion Motion may influence neglect in stroke patients. The integrity of the optic radiation may be a predictor of whether motion increases or decreases the severity of neglect symptoms. PMID:26158619

  13. An events based algorithm for distributing concurrent tasks on multi-core architectures

    NASA Astrophysics Data System (ADS)

    Holmes, David W.; Williams, John R.; Tilke, Peter

    2010-02-01

    In this paper, a programming model is presented which enables scalable parallel performance on multi-core shared memory architectures. The model has been developed for application to a wide range of numerical simulation problems. Such problems involve time stepping or iteration algorithms where synchronization of multiple threads of execution is required. It is shown that traditional approaches to parallelism including message passing and scatter-gather can be improved upon in terms of speed-up and memory management. Using spatial decomposition to create orthogonal computational tasks, a new task management algorithm called H-Dispatch is developed. This algorithm makes efficient use of memory resources by limiting the need for garbage collection and takes optimal advantage of multiple cores by employing a "hungry" pull strategy. The technique is demonstrated on a simple finite difference solver and results are compared to traditional MPI and scatter-gather approaches. The H-Dispatch approach achieves near linear speed-up with results for efficiency of 85% on a 24-core machine. It is noted that the H-Dispatch algorithm is quite general and can be applied to a wide class of computational tasks on heterogeneous architectures involving multi-core and GPGPU hardware.

  14. Genocide Exposure and Subsequent Suicide Risk: A Population-Based Study.

    PubMed

    Levine, Stephen Z; Levav, Itzhak; Yoffe, Rinat; Becher, Yifat; Pugachova, Inna

    2016-01-01

    The association between periods of genocide-related exposures and suicide risk remains unknown. Our study tests that association using a national population-based study design. The source population comprised of all persons born during1922-1945 in Nazi-occupied or dominated European nations, that immigrated to Israel by 1965, were identified in the Population Register (N = 220,665), and followed up for suicide to 2014, totaling 16,953,602 person-years. The population was disaggregated to compare a trauma gradient among groups that immigrated before (indirect, n = 20,612, 9%); during (partial direct, n = 17,037, 8%); or after (full direct, n = 183,016, 83%) exposure to the Nazi era. Also, the direct exposure groups were examined regarding pre- or post-natal exposure periods. Cox regression models were used to compute Hazard Ratios (HR) of suicide risk to compare the exposure groups, adjusting for confounding by gender, residential SES and history of psychiatric hospitalization. In the total population, only the partial direct exposure subgroup was at greater risk compared to the indirect exposure group (HR = 1.73, 95% CI, 1.10, 2.73; P < .05). That effect replicated in six sensitivity analyses. In addition, sensitivity analyses showed that exposure at ages 13 plus among females, and follow-up by years since immigration were associated with a greater risk; whereas in utero exposure among persons with no psychiatric hospitalization and early postnatal exposure among males were at a reduced risk. Tentative mechanisms impute biopsychosocial vulnerability and natural selection during early critical periods among males, and feelings of guilt and entrapment or defeat among females. PMID:26901411

  15. Genocide Exposure and Subsequent Suicide Risk: A Population-Based Study

    PubMed Central

    Levine, Stephen Z.; Levav, Itzhak; Yoffe, Rinat; Becher, Yifat; Pugachova, Inna

    2016-01-01

    The association between periods of genocide-related exposures and suicide risk remains unknown. Our study tests that association using a national population-based study design. The source population comprised of all persons born during1922-1945 in Nazi-occupied or dominated European nations, that immigrated to Israel by 1965, were identified in the Population Register (N = 220,665), and followed up for suicide to 2014, totaling 16,953,602 person-years. The population was disaggregated to compare a trauma gradient among groups that immigrated before (indirect, n = 20,612, 9%); during (partial direct, n = 17,037, 8%); or after (full direct, n = 183,016, 83%) exposure to the Nazi era. Also, the direct exposure groups were examined regarding pre- or post-natal exposure periods. Cox regression models were used to compute Hazard Ratios (HR) of suicide risk to compare the exposure groups, adjusting for confounding by gender, residential SES and history of psychiatric hospitalization. In the total population, only the partial direct exposure subgroup was at greater risk compared to the indirect exposure group (HR = 1.73, 95% CI, 1.10, 2.73; P < .05). That effect replicated in six sensitivity analyses. In addition, sensitivity analyses showed that exposure at ages 13 plus among females, and follow-up by years since immigration were associated with a greater risk; whereas in utero exposure among persons with no psychiatric hospitalization and early postnatal exposure among males were at a reduced risk. Tentative mechanisms impute biopsychosocial vulnerability and natural selection during early critical periods among males, and feelings of guilt and entrapment or defeat among females. PMID:26901411

  16. Development of a software based automatic exposure control system for use in image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Morton, Daniel R.

    Modern image guided radiation therapy involves the use of an isocentrically mounted imaging system to take radiographs of a patient's position before the start of each treatment. Image guidance helps to minimize errors associated with a patients setup, but the radiation dose received by patients from imaging must be managed to ensure no additional risks. The Varian On-Board Imager (OBI) (Varian Medical Systems, Inc., Palo Alto, CA) does not have an automatic exposure control system and therefore requires exposure factors to be manually selected. Without patient specific exposure factors, images may become saturated and require multiple unnecessary exposures. A software based automatic exposure control system has been developed to predict optimal, patient specific exposure factors. The OBI system was modelled in terms of the x-ray tube output and detector response in order to calculate the level of detector saturation for any exposure situation. Digitally reconstructed radiographs are produced via ray-tracing through the patients' volumetric datasets that are acquired for treatment planning. The ray-trace determines the attenuation of the patient and subsequent x-ray spectra incident on the imaging detector. The resulting spectra are used in the detector response model to determine the exposure levels required to minimize detector saturation. Images calculated for various phantoms showed good agreement with the images that were acquired on the OBI. Overall, regions of detector saturation were accurately predicted and the detector response for non-saturated regions in images of an anthropomorphic phantom were calculated to generally be within 5 to 10 % of the measured values. Calculations were performed on patient data and found similar results as the phantom images, with the calculated images being able to determine detector saturation with close agreement to images that were acquired during treatment. Overall, it was shown that the system model and calculation method could potentially be used to predict patients' exposure factors before their treatment begins, thus preventing the need for multiple exposures.

  17. Evaluation of the stability of polymer-based plasmid DNA delivery systems after ultrasound exposure.

    PubMed

    Kuo, Jung-hua Steven; Jan, Ming-shiou; Sung, K C

    2003-05-12

    Under ultrasound exposure, the stability of plasmid DNA protected by polymer-based gene delivery system is an important factor for achieving optimal transfection into cells. We have evaluated the effectiveness of various polymer-based plasmid DNA delivery systems, which are interactive polymers and cationic polymers, to avoid shear degradation induced by ultrasound exposure. Alternatively, it is shown that sonication of plasmid DNA for exposure time as low as 10s resulted in total DNA fragmentation and the loss of transfection potency in NIH/3T3 cells. Among these polymer-based plasmid DNA delivery systems, only cationic polymers had the ability to provide the protection of plasmid DNA from ultrasonic degradation as indicated by the reservation in supercoiled circular (SC) and open circular (OC) forms of plasmid DNA on the agarose gel electrophoresis. The DNA stability protected by cationic polymers decreased after ultrasound exposure in 1M sodium chloride solution. Also, higher molecular weight of cationic polymers and sufficient cationic polymer/DNA weight ratios are essential to prevent DNA from degradation under ultrasound exposure in aqueous or salt solution. These results suggest that the protective mechanism by cationic polymers is due to the attractive bonding between cationic polymer and negative plasmid DNA. Whereas, DNA condensation alone provoked by the addition of polyethylene glycols was not sufficient to resist the DNA fragmentation induced by ultrasound exposure. PMID:12711163

  18. A job-exposure matrix for use in population based studies in England and Wales.

    PubMed Central

    Pannett, B; Coggon, D; Acheson, E D

    1985-01-01

    The job-exposure matrix described has been developed for use in population based studies of occupational morbidity and mortality in England and Wales. The job axis of the matrix is based on the Registrar General's 1966 classification of occupations and 1968 classification of industries, and comprises 669 job categories. The exposure axis is made up of 49 chemical, physical, and biological agents, most of which are known or suspected causes of occupational disease. In the body of the matrix associations between jobs and exposures are graded to four levels. The matrix has been applied to data from a case-control study of lung cancer in which occupational histories were elicited by means of a postal questionnaire. Estimates of exposure to five known or suspected carcinogens (asbestos, chromates, cutting oils, formaldehyde, and inhaled polycyclic aromatic hydrocarbons were compared with those obtained by detailed review of individual occupational histories. When the matrix was used exposures were attributed to jobs more frequently than on the basis of individual histories. Lung cancer was significantly more common among subjects classed by the matrix as having potential exposure to chromates, but neither method of assigning exposures produced statistically significant associations with asbestos or polycyclic aromatic hydrocarbons. Possible explanations for the failure to show a clear effect of these known carcinogens are discussed. The greater accuracy of exposures inferred directly from individual histories was reflected in steeper dose response curves for asbestos, chromates, and polycyclic aromatic hydrocarbons. The improvement over results obtained with the matrix, however, was not great. For occupational data of the type examined in this study, direct exposure estimates offer little advantage over those provided at lower cost by a matrix. PMID:4063222

  19. Task Importance Affects Event-based Prospective Memory Performance in Adults with HIV-Associated Neurocognitive Disorders and HIV-infected Young Adults with Problematic Substance Use

    PubMed Central

    Woods, Steven Paul; Doyle, Katie L.; Morgan, Erin E.; Naar-King, Sylvie; Outlaw, Angulique Y.; Nichols, Sharon L.; Loft, Shayne

    2014-01-01

    Objective Two experiments were conducted to examine the effects of task importance on event-based prospective memory (PM) in separate samples of adults with HIV-associated Neurocognitive Disorders (HAND) and HIV-infected young adults with Substance Use Disorders (SUD). Method All participants completed three conditions of an ongoing lexical decision task: 1) without PM task requirements; 2) with PM task requirements that emphasized the importance of the ongoing task; and 3) with PM task requirements that emphasized the importance of the PM task. Results In both experiments, all HIV+ groups showed the expected increase in response costs to the ongoing task when the PM task’s importance was emphasized. In Experiment 1, individuals with HAND showed significantly lower PM accuracy as compared to HIV+ subjects without HAND when the importance of the ongoing task was emphasized, but improved significantly and no longer differed from HIV+ subjects without HAND when the PM task was emphasized. A similar pattern of findings emerged in Experiment 2, whereby HIV+ young adults with SUD (especially cannabis) showed significant improvements in PM accuracy when the PM task was emphasized. Conclusions Findings suggest that both HAND and SUD may increase the amount of cognitive attentional resources that need to be allocated to support PM performance in persons living with HIV infection. PMID:24834469

  20. DEVELOPMENT OF MODEL-BASED AIR POLLUTION EXPOSURE METRICS FOR USE IN EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

  1. "Development of Model-Based Air Pollution Exposure Metrics for use in Epidemiologic Studies"

    EPA Science Inventory

    Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

  2. A Community-Based Initiative to Reduce Children's Exposure to Toxics in Household Products

    ERIC Educational Resources Information Center

    Blackman, Anne Berlin; Luskin, Jack

    2006-01-01

    Purpose--The purpose of this paper is to explore the efficacy of a community-based outreach initiative, piloted in Worcester, Massachusetts, to reduce children's exposure to toxic chemicals in common household products by changing parental behavior regarding product purchase and use. Design/methodology/approach--The program model was based on the…

  3. A Community-Based Initiative to Reduce Children's Exposure to Toxics in Household Products

    ERIC Educational Resources Information Center

    Blackman, Anne Berlin; Luskin, Jack

    2006-01-01

    Purpose--The purpose of this paper is to explore the efficacy of a community-based outreach initiative, piloted in Worcester, Massachusetts, to reduce children's exposure to toxic chemicals in common household products by changing parental behavior regarding product purchase and use. Design/methodology/approach--The program model was based on the

  4. Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model.

    PubMed

    Wei, Binnian; Isukapalli, Sastry S; Weisel, Clifford P

    2013-07-01

    Assessment of potential health risks to flight attendants from exposure to pyrethroid insecticides, used for aircraft disinsection, is limited because of (a) lack of information on exposures to these insecticides, and (b) lack of tools for linking these exposures to biomarker data. We developed and evaluated a physiologically based pharmacokinetic (PBPK) model to assess the exposure of flight attendants to the pyrethroid insecticide permethrin attributable to aircraft disinsection. The permethrin PBPK model was developed by adapting previous models for pyrethroids, and was parameterized using currently available metabolic parameters for permethrin. The human permethrin model was first evaluated with data from published human studies. Then, it was used to estimate urinary metabolite concentrations of permethrin in flight attendants who worked in aircrafts, which underwent residual and pre-flight spray treatments. The human model was also applied to analyze the toxicokinetics following permethrin exposures attributable to other aircraft disinsection scenarios. Predicted levels of urinary 3-phenoxybenzoic acid (3-PBA), a metabolite of permethrin, following residual disinsection treatment were comparable to the measurements made for flight attendants. Simulations showed that the median contributions of the dermal, oral and inhalation routes to permethrin exposure in flight attendants were 83.5%, 16.1% and 0.4% under residual treatment scenario, respectively, and were 5.3%, 5.0% and 89.7% under pre-flight spray scenario, respectively. The PBPK model provides the capability to simulate the toxicokinetic profiles of permethrin, and can be used in the studies on human exposure to permethrin. PMID:23462847

  5. Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model

    PubMed Central

    Wei, Binnian; Isukapalli, Sastry S.; Weisel, Clifford P.

    2014-01-01

    Assessment of potential health risks to flight attendants from exposure to pyrethroid insecticides, used for aircraft disinsection, is limited because of (a) lack of information on exposures to these insecticides, and (b) lack of tools for linking these exposures to biomarker data. We developed and evaluated a physiologically based pharmacokinetic (PBPK) model to assess the exposure of flight attendants to the pyrethroid insecticide permethrin attributable to aircraft disinsection. The permethrin PBPK model was developed by adapting previous models for pyrethroids, and was parameterized using currently available metabolic parameters for permethrin. The human permethrin model was first evaluated with data from published human studies. Then, it was used to estimate urinary metabolite concentrations of permethrin in flight attendants who worked in aircrafts, which underwent residual and pre-flight spray treatments. The human model was also applied to analyze the toxicokinetics following permethrin exposures attributable to other aircraft disinsection scenarios. Predicted levels of urinary 3-phenoxybenzoic acid (3-PBA), a metabolite of permethrin, following residual disinsection treatment were comparable to the measurements made for flight attendants. Simulations showed that the median contributions of the dermal, oral and inhalation routes to permethrin exposure in flight attendants were 83.5%, 16.1% and 0.4% under residual treatment scenario, respectively, and were 5.3%, 5.0% and 89.7% under pre-flight spray scenario, respectively. The PBPK model provides the capability to simulate the toxicokinetic profiles of permethrin, and can be used in the studies on human exposure to permethrin. PMID:23462847

  6. Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations

    PubMed Central

    Rowley, Jack T; Joyner, Ken H

    2012-01-01

    This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles. PMID:22377680

  7. Sensitivity Analyses of Exposure Estimates from a Quantitative Job-exposure Matrix (SYN-JEM) for Use in Community-based Studies

    PubMed Central

    Peters, Susan

    2013-01-01

    Objectives: We describe the elaboration and sensitivity analyses of a quantitative job-exposure matrix (SYN-JEM) for respirable crystalline silica (RCS). The aim was to gain insight into the robustness of the SYN-JEM RCS estimates based on critical decisions taken in the elaboration process. Methods: SYN-JEM for RCS exposure consists of three axes (job, region, and year) based on estimates derived from a previously developed statistical model. To elaborate SYN-JEM, several decisions were taken: i.e. the application of (i) a single time trend; (ii) region-specific adjustments in RCS exposure; and (iii) a prior job-specific exposure level (by the semi-quantitative DOM-JEM), with an override of 0 mg/m3 for jobs a priori defined as non-exposed. Furthermore, we assumed that exposure levels reached a ceiling in 1960 and remained constant prior to this date. We applied SYN-JEM to the occupational histories of subjects from a large international pooled community-based case–control study. Cumulative exposure levels derived with SYN-JEM were compared with those from alternative models, described by Pearson correlation (Rp) and differences in unit of exposure (mg/m3-year). Alternative models concerned changes in application of job- and region-specific estimates and exposure ceiling, and omitting the a priori exposure ranking. Results: Cumulative exposure levels for the study subjects ranged from 0.01 to 60 mg/m3-years, with a median of 1.76 mg/m3-years. Exposure levels derived from SYN-JEM and alternative models were overall highly correlated (Rp > 0.90), although somewhat lower when omitting the region estimate (Rp = 0.80) or not taking into account the assigned semi-quantitative exposure level (Rp = 0.65). Modification of the time trend (i.e. exposure ceiling at 1950 or 1970, or assuming a decline before 1960) caused the largest changes in absolute exposure levels (26–33% difference), but without changing the relative ranking (Rp = 0.99). Conclusions: Exposure estimates derived from SYN-JEM appeared to be plausible compared with (historical) levels described in the literature. Decisions taken in the development of SYN-JEM did not critically change the cumulative exposure levels. The influence of region-specific estimates needs to be explored in future risk analyses. PMID:22805750

  8. Calculation of lifetime lung cancer risks associated with radon exposure, based on various models and exposure scenarios.

    PubMed

    Hunter, Nezahat; Muirhead, Colin R; Bochicchio, Francesco; Haylock, Richard G E

    2015-09-01

    The risk of lung cancer mortality up to 75 years of age due to radon exposure has been estimated for both male and female continuing, ex- and never-smokers, based on various radon risk models and exposure scenarios. We used risk models derived from (i) the BEIR VI analysis of cohorts of radon-exposed miners, (ii) cohort and nested case-control analyses of a European cohort of uranium miners and (iii) the joint analysis of European residential radon case-control studies. Estimates of the lifetime lung cancer risk due to radon varied between these models by just over a factor of 2 and risk estimates based on models from analyses of European uranium miners exposed at comparatively low rates and of people exposed to radon in homes were broadly compatible. For a given smoking category, there was not much difference in lifetime lung cancer risk between males and females. The estimated lifetime risk of radon-induced lung cancer for exposure to a concentration of 200 Bq m(-3) was in the range 2.98-6.55% for male continuing smokers and 0.19-0.42% for male never-smokers, depending on the model used and assuming a multiplicative relationship for the joint effect of radon and smoking. Stopping smoking at age 50 years decreases the lifetime risk due to radon by around a half relative to continuing smoking, but the risk for ex-smokers remains about a factor of 5-7 higher than that for never-smokers. Under a sub-multiplicative model for the joint effect of radon and smoking, the lifetime risk of radon-induced lung cancer was still estimated to be substantially higher for continuing smokers than for never smokers. Radon mitigation-used to reduce radon concentrations at homes-can also have a substantial impact on lung cancer risk, even for persons in their 50 s; for each of continuing smokers, ex-smokers and never-smokers, radon mitigation at age 50 would lower the lifetime risk of radon-induced lung cancer by about one-third. To maximise risk reductions, smokers in high-radon homes should both stop smoking and remediate their homes. PMID:26083042

  9. Hong Kong Grade 6 Students' Performance and Mathematical Reasoning in Decimals Tasks: Procedurally Based or Conceptually Based?

    ERIC Educational Resources Information Center

    Lai, Mun Yee; Murray, Sara

    2015-01-01

    Most studies of students' understanding of decimals have been conducted within Western cultural settings. The broad aim of the present research was to gain insight into Chinese Hong Kong grade 6 students' general performance on a variety of decimals tasks. More specifically, the study aimed to explore students' mathematical…

  10. The Secure Base Script and the Task of Caring for Elderly Parents: Implications for Attachment Theory and Clinical Practice

    PubMed Central

    Chen, Cory K.; Waters, Harriet Salatas; Hartman, Marilyn; Zimmerman, Sheryl; Miklowitz, David J.; Waters, Everett

    2013-01-01

    This study explores links between adults’ attachment representations and the task of caring for elderly parents with dementia. Participants were 87 adults serving as primary caregivers of a parent or parent-in-law with dementia. Waters and Waters’ (2006) Attachment Script Assessment was adapted to assess script-like attachment representation in the context of caring for their elderly parent. The quality of adult-elderly parent interactions was assessed using the Level of Expressed Emotions Scale (Cole & Kazarian, 1988) and self-report measures of caregivers’ perception of caregiving as difficult. Caregivers’ secure base script knowledge predicted lower levels of negative expressed emotion. This effect was moderated by the extent to which participants experienced caring for elderly parents as difficult. Attachment representations played a greater role in caregiving when caregiving tasks were perceived as more difficult. These results support the hypothesis that attachment representations influence the quality of care that adults provide their elderly parents. Clinical implications are discussed. PMID:23582012

  11. Electric Vehicle Preparedness: Task 2, Identification of Vehicles for Installation of Data Loggers for Marine Corps Base Camp Lejeune

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-02-01

    In Task 1, a survey was completed of the inventory of non-tactical fleet vehicles at the Marine Corps Base Camp Lejeune (MCBCL) to characterize the fleet. This information and characterization was used to select vehicles for further monitoring, which involves data logging of vehicle movements in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provides observations related to placement of PEV charging infrastructure. This report provides the list of vehicles selected by MCBCL and Intertek for further monitoring and fulfills the Task 2 requirements.

  12. A multilevel modeling approach to examining individual differences in skill acquisition for a computer-based task.

    PubMed

    Nair, Sankaran N; Czaja, Sara J; Sharit, Joseph

    2007-06-01

    This article explores the role of age, cognitive abilities, prior experience, and knowledge in skill acquisition for a computer-based simulated customer service task. Fifty-two participants aged 50-80 performed the task over 4 consecutive days following training. They also completed a battery that assessed prior computer experience and cognitive abilities. The data indicated that overall quality and efficiency of performance improved with practice. The predictors of initial level of performance and rate of change in performance varied according to the performance parameter assessed. Age and fluid intelligence predicted initial level and rate of improvement in overall quality, whereas crystallized intelligence and age predicted initial e-mail processing time, and crystallized intelligence predicted rate of change in e-mail processing time over days. We discuss the implications of these findings for the design of intervention strategies. PMID:17565169

  13. International data base of exposure measurements in the pulp, paper and paper product industries.

    PubMed

    Kauppinen, T; Teschke, K; Savela, A; Kogevinas, M; Boffetta, P

    1997-01-01

    An international data base of exposure measurements in the pulp, paper and paper product industries was constructed to be used in exposure assessment for epidemiology studies and hazard control. Industrial hygiene and biological monitoring data were collected from countries participating in the multicentric study of the International Agency for Research on Cancer. Each measurement was characterized by country, mill type and number, department, job, agent measured, sampling method, measurement result in the standard unit, duration and date of sampling, assessment of representativeness, measurer, purpose of measurements, and remarks (e.g. on measurement sites and biases). Over 31,000 measurement results on 246 different chemical agents from 13 countries were available from pulp (45% of measurements), paper/paperboard/recycling (12%) and paper product (11%) mills or from their non-production departments (23%). Most measurements (82%) were carried out after 1980. The most frequently measured group of agents was inorganic gases (35%), followed by organic compounds (25%), solvents (18%), mineral dusts (12%), metals (6%) and bioaerosols (3%). Over 90% of the measurements were without an obvious bias, but their true representativeness is difficult to assess. Concentrations of various agents, including sulfur dioxide, chlorine dioxide, carbon monoxide, nitrogen dioxide, ozone, ammonia, formaldehyde and some solvents, often exceeded current occupational exposure limits. This data base summarizes a great deal of previously unpublished exposure data, provides a unique opportunity to study exposure patterns at the international level and identifies exposure situations that require further attention and investigation. PMID:9253640

  14. Impact of Hospital-Based Environmental Exposures on Neurodevelopmental Outcomes of Preterm Infants

    PubMed Central

    Santos, Janelle; Pearce, Sarah E.; Stroustrup, Annemarie

    2015-01-01

    Purpose of review Over 300,000 infants are hospitalized in a neonatal intensive care unit (NICU) in the United States annually during a developmental period critical to later neurobehavioral function. Environmental exposures during the fetal period and infancy have been shown to impact long-term neurobehavioral outcomes. This review summarizes evidence linking NICU-based environmental exposures to neurodevelopmental outcomes of children born preterm, Recent findings Preterm infants experience multiple exposures important to neurodevelopment during the NICU hospitalization. The physical layout of the NICU, management of light and sound, social interactions with parents and NICU staff, and chemical exposures via medical equipment are important to long-term neurobehavioral outcomes in this highly vulnerable population. Summary Existing research documents NICU-based exposure to 1) neurotoxic chemicals, 2) aberrant light, 3) excess sound, and 4) restricted social interaction. In total, this creates an environment of co-existing excesses (chemicals, light, sound) and deprivation (touch, speech). The full impact of these co-exposures on the long-term neurodevelopment of preterm infants has not been adequately elucidated. Research into the importance of the NICU from an environmental health perspective is in its infancy, but could provide understanding about critical modifiable factors impacting the neurobehavioral health of hundreds of thousands of children each year. PMID:25635585

  15. Embodied Action Improves Cognition in Children: Evidence from a Study Based on Piagetian Conservation Tasks.

    PubMed

    Lozada, Mariana; Carro, Natalia

    2016-01-01

    Converging evidence highlights the relevance of embodied cognition in learning processes. In this study we evaluate whether embodied action (enaction) improves cognitive understanding in children. Using the Piagetian conservation tasks in 6-7 year olds, we analyzed quantity conservation conceptualization in children who were active participants in the transformation process and compared these results to those of children who were mere observers of an adult's demonstration (as traditionally conducted). The investigation was performed with 105 first-graders. Conservation tasks were demonstrated to half the children, while the other half actively carried out the transformation of matter. Our findings showed that active manipulation of the material helped children recognize quantity invariance in a higher proportion than when the demonstration was only observed. That is, their enactive experience enabled them to comprehend conservation phenomena more easily than if they were merely passive observers. The outcome of this research thus emphasizes how active participation benefits cognitive processes in learning contexts, promoting autonomy, and agency during childhood. PMID:27047420

  16. The creation of a superstitious belief regarding putters in a laboratory-based golfing task

    PubMed Central

    Churchill, Andrew; Taylor, Jamie A.; Parkes, Royston

    2015-01-01

    The objective was to determine the extent to which it was possible to induce superstitious behaviour and beliefs in a golf putting task in a laboratory. Participants (N = 28) took part in a putting task using three identical clubs in which visual feedback regarding performance was restricted. Participants were provided with verbal feedback of their performance, which was honest when they used one putter, negative with a second putter (they did better than they were told) and positive with a third (they did worse than they were told). After this initial acquisition phase, a competition was announced and participants were asked to select a putter they would like to use. The participants were then asked to rate various qualities of the putters. Significantly more participants selected the “positive” putter for the competition (N = 22) compared to the “negative” putter (N = 1), p < .001. In addition, participants claimed that the positive putter had a better weight, was more comfortable and easier to use than the negative putter (all p < .001). Overall, this evidence can be taken to show that a superstitious belief can be formed in a short amount of time within a laboratory setting and that it can affect both the perceptions and choices of an individual. PMID:26877722

  17. Embodied Action Improves Cognition in Children: Evidence from a Study Based on Piagetian Conservation Tasks

    PubMed Central

    Lozada, Mariana; Carro, Natalia

    2016-01-01

    Converging evidence highlights the relevance of embodied cognition in learning processes. In this study we evaluate whether embodied action (enaction) improves cognitive understanding in children. Using the Piagetian conservation tasks in 6–7 year olds, we analyzed quantity conservation conceptualization in children who were active participants in the transformation process and compared these results to those of children who were mere observers of an adult's demonstration (as traditionally conducted). The investigation was performed with 105 first-graders. Conservation tasks were demonstrated to half the children, while the other half actively carried out the transformation of matter. Our findings showed that active manipulation of the material helped children recognize quantity invariance in a higher proportion than when the demonstration was only observed. That is, their enactive experience enabled them to comprehend conservation phenomena more easily than if they were merely passive observers. The outcome of this research thus emphasizes how active participation benefits cognitive processes in learning contexts, promoting autonomy, and agency during childhood. PMID:27047420

  18. AutomaDeD: Automata-Based Debugging for Dissimilar Parallel Tasks

    SciTech Connect

    Bronevetsky, G; Laguna, I; Bagchi, S; de Supinski, B R; Ahn, D; Schulz, M

    2010-03-23

    Today's largest systems have over 100,000 cores, with million-core systems expected over the next few years. This growing scale makes debugging the applications that run on them a daunting challenge. Few debugging tools perform well at this scale and most provide an overload of information about the entire job. Developers need tools that quickly direct them to the root cause of the problem. This paper presents AutomaDeD, a tool that identifies which tasks of a large-scale application first manifest a bug at a specific code region at a specific point during program execution. AutomaDeD creates a statistical model of the application's control-flow and timing behavior that organizes tasks into groups and identifies deviations from normal execution, thus significantly reducing debugging effort. In addition to a case study in which AutomaDeD locates a bug that occurred during development of MVAPICH, we evaluate AutomaDeD on a range of bugs injected into the NAS parallel benchmarks. Our results demonstrate that detects the time period when a bug first manifested itself with 90% accuracy for stalls and hangs and 70% accuracy for interference faults. It identifies the subset of processes first affected by the fault with 80% accuracy and 70% accuracy, respectively and the code region where where the fault first manifested with 90% and 50% accuracy, respectively.

  19. An industrial radiography exposure device based on measurement of transmitted gamma-ray intensity

    NASA Astrophysics Data System (ADS)

    Polee, C.; Chankow, N.; Srisatit, S.; Thong-Aram, D.

    2015-05-01

    In film radiography, underexposure and overexposure may happen particularly when lacking information of specimen material and hollowness. This paper describes a method and a device for determining exposure in industrial gamma-ray radiography based on quick measurement of transmitted gamma-ray intensity with a small detector. Application software was developed for Android mobile phone to remotely control the device and to display counting data via Bluetooth communication. Prior to film exposure, the device is placed behind a specimen to measure transmitted intensity which is inversely proportional to the exposure. Unlike in using the conventional exposure curve, correction factors for source decay, source-to- film distance, specimen thickness and kind of material are not needed. The developed technique and device make radiographic process economic, convenient and more reliable.

  20. Pharmacological enhancement of exposure-based treatment in PTSD: a qualitative review

    PubMed Central

    de Kleine, Rianne A.; Rothbaum, Barbara O.; van Minnen, Agnes

    2013-01-01

    There is a good amount of evidence that exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD). Notwithstanding its efficacy, there is room for improvement, since a large proportion of patients does not benefit from treatment. Recently, an interesting new direction in the improvement of exposure therapy efficacy for PTSD emerged. Basic research found evidence of the pharmacological enhancement of the underlying learning and memory processes of exposure therapy. The current review aims to give an overview of clinical studies on pharmacological enhancement of exposure-based treatment for PTSD. The working mechanisms, efficacy studies in PTSD patients, and clinical utility of four different pharmacological enhancers will be discussed: d-cycloserine, MDMA, hydrocortisone, and propranolol. PMID:24147208