Sample records for task based exposure

  1. Task-based Dermal Exposure Models for Regulatory Risk Assessment

    Microsoft Academic Search

    NICHOLAS D. WARREN; HANS MARQUART; YVETTE CHRISTOPHER; JUHA LAITINEN; JOOP J. VAN HEMMEN

    2006-01-01

    The regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particular class of chemical or application. The EU project RISKOFDERM has gathered a considerable number of new measurements of dermal exposure together with detailed contex- tual information. This article describes the

  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. Task based exposure assessment in ergonomic epidemiology: a study of upper arm elevation in the jobs of machinists, car mechanics, and house painters

    PubMed Central

    Svendsen, S; Mathiassen, S; Bonde, J

    2005-01-01

    Aims: To explore the precision of task based estimates of upper arm elevation in three occupational groups, compared to direct measurements of job exposure. Methods: Male machinists (n = 26), car mechanics (n = 23), and house painters (n = 23) were studied. Whole day recordings of upper arm elevation were obtained for four consecutive working days, and associated task information was collected in diaries. For each individual, task based estimates of job exposure were calculated by weighting task exposures from a collective database by task proportions according to the diaries. These estimates were validated against directly measured job exposures using linear regression. The performance of the task based approach was expressed through the gain in precision of occupational group mean exposures that could be obtained by adding subjects with task based estimates to a group of subjects with measured job exposures in a "validation" design. Results: In all three occupations, tasks differed in mean exposure, and task proportions varied between individuals. Task based estimation proved inefficient, with squared correlation coefficients only occasionally exceeding 0.2 for the relation between task based and measured job exposures. Consequently, it was not possible to substantially improve the precision of an estimated group mean by including subjects whose job exposures were based on task information. Conclusions: Task based estimates of mechanical job exposure can be very imprecise, and only marginally better than estimates based on occupation. It is recommended that investigators in ergonomic epidemiology consider the prospects of task based exposure assessment carefully before placing resources at obtaining task information. Strategies disregarding tasks may be preferable in many cases. PMID:15613604

  4. Task-Based Assessment of Occupational Vibration and Noise Exposures in Forestry Workers

    Microsoft Academic Search

    Richard Neitzel; Michael Yost

    2002-01-01

    Forty-two noise exposures and 164 whole-body (WBV) and hand-arm (HAV) vibration exposures were collected from 43 forestry workers in six trades employed by two forestry companies. Data were collected on 10 days over 8 weeks during various felling, logging, and log handling operations. Up to 5 volunteers were monitored for noise and vibration daily using datalogging noise dosimeters, which provided

  5. 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 ?g/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

  6. Hexavalent Chromium Exposure and Control in Welding Tasks

    Microsoft Academic Search

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

    2010-01-01

    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

  7. Pesticide exposure and sprayer's task goals: comparison between vineyards and

    E-print Network

    Pesticide exposure and sprayer's task goals: comparison between vineyards and greenhouses. Mandy of pesticide spraying. The objective of this intervention was to identify factors explaining the influence of crops is dependent on the use of pesticides. Plant protection products (PPP) are active substances

  8. Accuracy of task recall for epidemiological exposure assessment to construction noise

    PubMed Central

    Reeb-Whitaker, C; Seixas, N; Sheppard, L; Neitzel, R

    2004-01-01

    Aims: To validate the accuracy of construction worker recall of task and environment based information; and to evaluate the effect of task recall on estimates of noise exposure. Methods: A cohort of 25 construction workers recorded tasks daily and had dosimetry measurements weekly for six weeks. Worker recall of tasks reported on the daily activity cards was validated with research observations and compared directly to task recall at a six month interview. Results: The mean LEQ noise exposure level (dBA) from dosimeter measurements was 89.9 (n = 61) and 83.3 (n = 47) for carpenters and electricians, respectively. The percentage time at tasks reported during the interview was compared to that calculated from daily activity cards; only 2/22 tasks were different at the nominal 5% significance level. The accuracy, based on bias and precision, of percentage time reported for tasks from the interview was 53–100% (median 91%). For carpenters, the difference in noise estimates derived from activity cards (mean 91.9 dBA) was not different from those derived from the questionnaire (mean 91.7 dBA). This trend held for electricians as well. For all subjects, noise estimates derived from the activity card and the questionnaire were strongly correlated with dosimetry measurements. The average difference between the noise estimate derived from the questionnaire and dosimetry measurements was 2.0 dBA, and was independent of the actual exposure level. Conclusions: Six months after tasks were performed, construction workers were able to accurately recall the percentage time they spent at various tasks. Estimates of noise exposure based on long term recall (questionnaire) were no different from estimates derived from daily activity cards and were strongly correlated with dosimetry measurements, overestimating the level on average by 2.0 dBA. PMID:14739379

  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. 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…

  11. Behavioral effects of a noisy environment: Task involvement versus passive exposure

    Microsoft Academic Search

    Joachim F. Wohlwill; Jack L. Nasar; David M. DeJoy; Hossein H. Foruzani

    1976-01-01

    Compared the effects of noise under active task involvement as opposed to passive exposure, using 80 undergraduate Ss who were assigned to 1 of 4 conditions representing 2 * 2 combinations of task vs no task and noise vs quiet. Performance on a dial-monitoring task was unaffected by noise. Ratings of interest and tenseness were significantly higher under the task

  12. Behavior-Based Segmentation of Demonstrated Tasks

    Microsoft Academic Search

    Nathan Koenig

    Robot learning from demonstration presents sev- eral challenges. Given a task demonstration, the robot must sense, understand, and learn appropriate task attributes. We propose a method for automatic segmentation of a complex demonstration into an ordered set of simpler behaviors. These behaviors present a significantly less complex domain for learning. Our method is based on empirically derived attributes of tasks

  13. 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…

  14. Analysis of radiation exposure for Task Force WARRIOR-Shot Smoky-Exercise Desert Rock, VII-VIII Operation Plumbbob. Final report, February 1978February 1979

    Microsoft Academic Search

    J. L. Goetz; D. Kaul; J. Klemm; J. T. McGahan

    1979-01-01

    The radiation exposures to Task Force WARRIOR troops who participated in Shot Smoky are determined and compared with film badge data gathered during Exercise Desert Rock VII-VIII. Fallout contours and decay rates are established and used to calculate total exposure, based on estimated stay time for various troop activities. Uncertainties are calculated for each parameter. Exposures are corrected to a

  15. Some Reflections on Task-Based Language Performance Assessment.

    ERIC Educational Resources Information Center

    Bachman, Lyle F.

    2002-01-01

    Discusses problems in task-based language assessment, including the definition and sampling of tasks, generalizations across tasks, interpretations about broad ability and language use domains, and the notion of task difficulty. (Author/VWL)

  16. TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA

    SciTech Connect

    Miller, William A [ORNL; Cheng, Mengdawn [ORNL; New, Joshua Ryan [ORNL; Ronnen, Levinson [Lawrence Berkeley National Laboratory (LBNL); Akbari, Hashem [Lawrence Berkeley National Laboratory (LBNL); Berhahl, Paul [Lawrence Berkeley National Laboratory (LBNL)

    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 r

  17. 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

  18. Automated Video Exposure Assessment of Repetitive Hand Activity Level for a Load Transfer Task

    PubMed Central

    Chen, Chia-Hsiung; Hu, Yu Hen; Yen, Thomas Y.

    2014-01-01

    Objective A new method is described for automatically quantifying repetitive hand activity using digital video processing. Background The hand activity level (HAL) is widely used for evaluating repetitive hand work. Conventional methods using either a trained observer on or off site, or manual off site video analysis, are often considered inaccurate, cumbersome or impractical for routine work assessment. Method A cross correlation-based template-matching algorithm was programmed to track the motion trajectory of a selected region of interest over successive video frames for a single camera to measure repetition frequency, duty cycle and HAL. A simple paced load transfer task was used to simulate a repetitive industrial activity. Twelve participants were videoed performing the task for varying HAL conditions. The automatically predicted HAL was compared to the manually measured HAL using frame-by-frame video analysis. Results Predicted frequency, duty cycle and HAL were in concert with the manually measured HAL conditions. The linear regression slope of the automatically predicted values with respect to the manually measured values were 0.98 (R2=.79), 1.27 (R2=.63), and 1.06 (R2=.77) for frequency, duty cycle, and HAL respectively. Conclusion A proof-of-concept for automatic video-based direct exposure assessment was demonstrated. Application The video assessment method for repetitive motion is promising for automatic, unobtrusive, and objective exposure assessment, which may offer broad availability using a camera enabled mobile device for helping evaluate, prevent and control exposure to repetitive motions related to upper extremity injuries in the workplace. PMID:23691826

  19. 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.

  20. Acute effects of 50 Hz magnetic field exposure on human visual task and cardiovascular performance

    SciTech Connect

    Whittington, C.J.; Podd, J.V.; Rapley, B.R. [Massey Univ., Palmerston North (New Zealand). Dept. of Psychology] [Massey Univ., Palmerston North (New Zealand). Dept. of Psychology

    1996-05-01

    One hundred subjects, males and females with ages ranging between 18 and 48 years, were studied under both field-exposed and sham-exposed conditions. A 50 Hz, 100 {micro}T magnetic field (MF) was used. To examine the effect of field exposure on performance, a two-alternative, forced-choice, duration-discrimination task with three levels of difficulty was used. The subject`s task was to decide which of two sequentially presented light flashes had the longer duration. The standard duration was 50 ms, and the alternative durations were 65, 100, or 125 ms. Both reaction time and percentage of correct responses were recorded for each subject. MF and sham exposure were for 9 min each. Blood pressure and heart rate were also measured before and following MF exposure and sham-exposure trials. The study was performed double blind, with the exposure order counterbalanced. Compared to sham exposure, MF exposure significantly decreased reaction time on the hardest level of the performance task. MF exposure did not reliably affect percentage correct or cardiovascular performance. It was demonstrated that a relatively high level of statistical power was the basis for the observed MF effect, and the need to pay closer attention to power levels in future research is discussed.

  1. Benzene Exposures Associated with Tasks Performed on Marine Vessels (Circa 1975 to 2000)

    Microsoft Academic Search

    Pamela R. D. Williams; Kathryn Robinson; Dennis J. Paustenbach

    2005-01-01

    In this article, we assemble and synthesize the available industrial hygiene data that describe exposure during the marine transport of benzene-containing products in the United States and abroad. A total of 25 studies were identified and summarized. The measured airborne concentrations of benzene on marine vessels were found to vary depending on several key factors, including the job task, vessel

  2. 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

  3. Characterizing task-based OpenMP programs.

    PubMed

    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

  4. Medical Assistant: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Newport News Public Schools, VA.

    This task analysis guide is designed to be used in combination with the "Health Occupations Education Service Area Resource" in order to implement competency-based education in the Medical Assistant program in Virginia. The task analysis guide contains the task inventory, suggested task sequence lists, and content outlines for the specific courses…

  5. Building tasks from verbal instructions: an EEG study on practice trial exposure and task structure complexity during novel sequences of behavior.

    PubMed

    Roberts, Gareth; Jones, Timothy W; Davis, Elizabeth A; Ly, Trang T; Anderson, Mike

    2014-12-01

    Configuring the mind to perform a novel task is an effortful process and one that is related to differences in general intelligence. Previous research has suggested that when participants are given instructions for a future task, representations of the rules contained in the instructions can influence subsequent behavior, even when the rules are not necessary to perform the upcoming task. One hypothesis for the continued activation of rule representations suggests that the practice trials participants perform before the experimental trials may instantiate the unnecessary task rules into participants' mental model of the task (i.e., the task space). To test this hypothesis, EEGs were recorded as participants (N = 66) completed a multirule task designed to contrast the effects of increasing task structure complexity and practice trial exposure. The results showed that, as was predicted, performance is significantly poorer when more task rules are specified in the task instructions. Practice trials with the extra rule did not affect task performance, indicating that an unacted verbal instruction is sufficient to incorporate the rule into participants' mental model of the task. The EEG results showed that instruction complexity was linked to a phasic increase in frontal theta synchronization but reduced posterior alpha and beta desynchronization. These changes in synchronization occurred during a time period of low intertrial phase coherence and suggest that participants were "checking the task rules" amidst a trial. This transient neural activity may reflect compensatory mechanisms for dealing with increased mind-wandering that is more likely to occur in complex tasks. PMID:24796598

  6. 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…

  7. Modeling of Task-Based Authorization Constraints in BPMN

    Microsoft Academic Search

    Christian Wolter; Andreas Schaad

    2007-01-01

    Workflows model and control the execution of business processes in an organisation by defining a set of tasks to be done.\\u000a The specification of workflows is well-elaborated and heavily tool supported. Task-based access control is tailored to specify\\u000a authorization constraints for task allocation in workflows. Existing workflow modeling notations do not support the description\\u000a of authorization constraints for task allocation

  8. Team Task Analysis: Identifying Tasks and Jobs That Are Team Based

    Microsoft Academic Search

    Winfred Arthur; Bryan D. Edwards; Suzanne T. Bell; Anton J. Villado; Winston Bennett

    2005-01-01

    This paper presents initial information on the development and validation of three team task analysis scales. These scales were designed to quantitatively assess the extent to which a group of tasks or a job is team based. During a 2-week period, 52 male students working in 4-person teams were trained to perform a complex highly interdependent computer-simulated combat mission consisting

  9. 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…

  10. 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

  11. Team task analysis: identifying tasks and jobs that are team based.

    PubMed

    Arthur, Winfred; Edwards, Bryan D; Bell, Suzanne T; Villado, Anton J; Bennett, Winston

    2005-01-01

    This paper presents initial information on the development and validation of three team task analysis scales. These scales were designed to quantitatively assess the extent to which a group of tasks or a job is team based. During a 2-week period, 52 male students working in 4-person teams were trained to perform a complex highly interdependent computer-simulated combat mission consisting of both individual- and team-based tasks. Our results indicated that the scales demonstrated high levels of interrater agreement. In addition, the scales differentiated between tasks that were predetermined to be individual versus team based. Finally, the results indicated that job-level ratings of team workflow were more strongly related to team performance than were aggregated task-level ratings of team-relatedness or team workflow. These results suggest that the scales presented here are an effective means of quantifying the extent to which tasks or jobs are team based. A research and practical implication of our findings is that the team task analysis scales could serve as criterion measures in the evaluation of team training interventions or predictors of team performance. PMID:16435704

  12. An ontology-based telemedicine tasks management system architecture

    Microsoft Academic Search

    Ebrahim Nageba; Jocelyne Fayn; Paul Rubel

    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

  13. Safeguard to control the behaviour of Task-Based Systems

    Microsoft Academic Search

    Xavier Talon; Christine Pierret-Golbreich; Orsay Cedex; Rennes Cedex

    1998-01-01

    First generation rule-based systems benefit of a lot of works and mathematical results. However they also have some limitations, often due to the implicit feature of their control. It is why, specific modelling primitives, like problem-solving methods and tasks, have been introduced in task- based frameworks in o rder to elicit t he problem- solving p rocess. However until now,

  14. Task classification for knowledge-based systems in industrial automation

    Microsoft Academic Search

    R. Leitch; M. Gallanti

    1992-01-01

    A formal classification of primitive tasks for knowledge-based system applications in industrial automation is presented. The classification is based on a system theoretic perspective using the direction of temporal reasoning as the metric for classification. This classification is canonical with respect to time and can, therefore, be used to define primitive elements in constructing more complex tasks that are termed

  15. Pesticide exposure and sprayer's task goals: comparison between vineyards and greenhouses.

    PubMed

    Lambert, Mandy; Richardson, James; Grimbuhler, Sonia

    2012-01-01

    Plant protection products are used in agriculture to improve yields, but this use can cause contamination of the environment and is also likely to have adverse short and long term effects on agricultural workers. The field study took place in greenhouses and vineyards where operators are involved in high levels of pesticide spraying. The objective of this intervention was to identify factors explaining the influence of task factors on the exposure of greenhouse growers and vineyard workers. Thirteen operators were selected for detailed observations during one session of spraying. Video recordings provide counts of physical contacts between the operator and all the surrounding surfaces during the spraying operation. Both in vineyards and in greenhouses, physical and temporal constraints are the predominant factors in establishing a specific spraying procedure. Every action taken by the operator is a result of a compromise between safety, task performance and quality. PMID:22317494

  16. Interface agents personalizing Web-based tasks

    Microsoft Academic Search

    Daniela Godoy; Silvia N. Schiaffino; Anal??a Amandi

    2004-01-01

    The volume of information available on the Web is constantly growing. Due to this situation, users looking for documents relevant to their interests need to identify them among all the available ones. Intelligent agents have become a solution to assist users in this task since they can retrieve, filter and organize information on behalf of their users. In this paper

  17. Task-Based Knowledge Management Computer Science

    E-print Network

    Leake, David B.

    these issues are addressed in the StampingAdvisor, a systemto aid the design of stamped automotive parts performance. Key issues include how to integrate knowledge access into the user's problem-solving process, how- port downstream task processes and build its memory of cases. Introduction The goal of knowledge

  18. 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...

  19. 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...

  20. The Creative task Creator: a tool for the generation of customized, Web-based creativity tasks.

    PubMed

    Pretz, Jean E; Link, John A

    2008-11-01

    This article presents a Web-based tool for the creation of divergent-thinking and open-ended creativity tasks. A Java program generates HTML forms with PHP scripting that run an Alternate Uses Task and/or open-ended response items. Researchers may specify their own instructions, objects, and time limits, or use default settings. Participants can also be prompted to select their best responses to the Alternate Uses Task (Silvia et al., 2008). Minimal programming knowledge is required. The program runs on any server, and responses are recorded in a standard MySQL database. Responses can be scored using the consensual assessment technique (Amabile, 1996) or Torrance's (1998) traditional scoring method. Adoption of this Web-based tool should facilitate creativity research across cultures and access to eminent creators. The Creative Task Creator may be downloaded from the Psychonomic Society's Archive of Norms, Stimuli, and Data, www.psychonomic.org/archive. PMID:19001404

  1. Cluster-based exposure variation analysis

    PubMed Central

    2013-01-01

    Background Static posture, repetitive movements and lack of physical variation are known risk factors for work-related musculoskeletal disorders, and thus needs to be properly assessed in occupational studies. The aims of this study were (i) to investigate the effectiveness of a conventional exposure variation analysis (EVA) in discriminating exposure time lines and (ii) to compare it with a new cluster-based method for analysis of exposure variation. Methods For this purpose, we simulated a repeated cyclic exposure varying within each cycle between “low” and “high” exposure levels in a “near” or “far” range, and with “low” or “high” velocities (exposure change rates). The duration of each cycle was also manipulated by selecting a “small” or “large” standard deviation of the cycle time. Theses parameters reflected three dimensions of exposure variation, i.e. range, frequency and temporal similarity. Each simulation trace included two realizations of 100 concatenated cycles with either low (??=?0.1), medium (??=?0.5) or high (??=?0.9) correlation between the realizations. These traces were analyzed by conventional EVA, and a novel cluster-based EVA (C-EVA). Principal component analysis (PCA) was applied on the marginal distributions of 1) the EVA of each of the realizations (univariate approach), 2) a combination of the EVA of both realizations (multivariate approach) and 3) C-EVA. The least number of principal components describing more than 90% of variability in each case was selected and the projection of marginal distributions along the selected principal component was calculated. A linear classifier was then applied to these projections to discriminate between the simulated exposure patterns, and the accuracy of classified realizations was determined. Results C-EVA classified exposures more correctly than univariate and multivariate EVA approaches; classification accuracy was 49%, 47% and 52% for EVA (univariate and multivariate), and C-EVA, respectively (p?exposure patterns differing with respect to the variability in cycle time duration. Conclusion While C-EVA had a higher accuracy than conventional EVA, both failed to detect differences in temporal similarity. The data-driven optimality of data reduction and the capability of handling multiple exposure time lines in a single analysis are the advantages of the C-EVA. PMID:23557439

  2. 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…

  3. Modelling tasks: a requirements analysis based on attention support services

    E-print Network

    Corran, Ruth

    , the task he is trying to complete, a lot of reasoning can be based on this context. In particular, we in the definition of Contextualised Attention Metadata (CAM). As CAM aims at tracking resources usage, identifying. In the process we will also highlight another important relation between CAM and task modelling, i.e. the fact

  4. Critical Task Characteristics in Problem-Based Learning

    ERIC Educational Resources Information Center

    Otting, Hans; Zwaal, Wichard

    2006-01-01

    Tasks and problems in problem-based learning (PBL) are supposed to trigger and structure the learning process. The quality of problems in PBL is generally regarded as an important driver of the individual and collaborative learning processes. Although the importance of the PBL task is widely recognized, there is a lack of empirical findings and…

  5. Mining group-based knowledge flows for sharing task knowledge

    Microsoft Academic Search

    Duen-Ren Liu; Chin-Hui Lai

    2011-01-01

    In an organization, knowledge is the most important resource in the creation of core competitive advantages. It is circulated and accumulated by knowledge flows (KFs) in the organization to support workers' task needs. Because workers accumulate knowledge of different domains, they may cooperate and participate in several task-based groups to satisfy their needs. In this paper, we propose algorithms that

  6. Task Sequencing for High-Level Sensor-Based Control

    Microsoft Academic Search

    Nicolas Mansard; François Chaumette

    2007-01-01

    ó Classical sensor-based approaches tend to constrain all the degrees of freedom of a robot during the execution of a task. In this article a new solution is proposed. The key idea is to divide the global full-constraining task into several subtasks that can be applied or inactivated to take into account potential constraints of the environment. Far from any

  7. Deadline-based scheduling of periodic task systems on multiprocessors

    Microsoft Academic Search

    Anand Srinivasan; Sanjoy K. Baruah

    2002-01-01

    We consider the problem of scheduling periodic task systems on multiprocessors and present a deadline-based scheduling algorithm for solving this problem. We show that our algorithm successfully schedules on m processors any periodic task system with utilization at most m2\\/(2m?1).

  8. Facilitating Experience Reuse: Towards a Task-Based Approach

    NASA Astrophysics Data System (ADS)

    Du, Ying; Chen, Liming; Hu, Bo; Patterson, David; Wang, Hui

    This paper proposes a task-based approach to facilitate experience reuse in knowledge-intensive work environments, such as the domain of Technical Support. We first present a real-world motivating scenario, product technical support in a global IT enterprise, by studying of which key characteristics of the application domain and user requirements are drawn and analysed. We then develop the associated architecture for enabling the work experience reuse process to address the issues identified from the motivating scenario. Central to the approach is the task ontology that seamlessly integrates different components of the architecture. Work experience reuse amounts to the discovery and retrieval of task instances. In order to compare task instances, we introduce the dynamic weighted task similarity measure that is able to tuning similarity value against the dynamically changing task contextual information. A case study has been carried out to evaluate the proposed approach.

  9. APA Presidential Task Force on Evidence-Based Practice

    Microsoft Academic Search

    Alvin R. Mahrer; Frederick L. Newman; John C. Norcross; Doris K. Silverman; Brian D. Smedley; Bruce E. Wampold; Drew I. Westen; Brian T. Yates; Nolan W. Zane; Geoffrey M. Reed; Lynn F. Bufka; Paul D. Nelson; Cynthia D. Belar; Merry Bullock

    The evidence-based practice movement has become an important feature of health care systems and health care policy. Within this context, the APA 2005 Presidential Task Force on Evidence-Based Practice defines and discusses evidence-based practice in psychology (EBPP). In an in- tegration of science and practice, the Task Force's report describes psychology's fundamental commitment to sophis- ticated EBPP and takes into

  10. 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…

  11. Impact of expert versus measurement-based occupational noise exposure estimates on exposure-response relationships

    Microsoft Academic Search

    Melissa C. Friesen; Hugh W. Davies; Aleck Ostry; Kay Teschke; Paul A. Demers

    2008-01-01

    Objective  Expert-judgment has frequently been used to assess quantitative exposure for epidemiologic studies, but accuracy varies widely\\u000a dependent on the type of exposure and the availability of measurements to anchor estimates. There is limited empirical evidence\\u000a of the sensitivity of exposure-response relationships to expert- versus measurement-based exposure assessment strategies.\\u000a We examined the sensitivity of the exposure-response relationship between occupational noise exposure

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

    SciTech Connect

    Shepard, S. Jeff; Wang Jihong; Flynn, Michael [Imaging Physics Department 056, Division of Diagnostic Imaging, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); 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.

  13. Task Delegation Based Access Control Models for Workflow Systems

    NASA Astrophysics Data System (ADS)

    Gaaloul, Khaled; Charoy, François

    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.

  14. 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.

  15. Tasks

    Microsoft Academic Search

    Paresh Malhotra; Keith Muir; Ian Reeves; George Duncan; Katrina Livingstone; Hazel Jackson; Caroline Hogg; Pauline Castle; Gemma Learmonth; Monika Harvey

    2007-01-01

    It is well established that patients with hemispatial neglect present with severe visuospatial impairments, but studies that have directly investigated visuomotor control have revealed diverging results, with some studies showing that neglect patients perform relatively better on such tasks. The present study compared the visuomotor performance of patients with and without neglect after right- hemisphere stroke with those of age-matched

  16. Graph-based analysis of brain connectivity during spelling task

    E-print Network

    Paris-Sud XI, Université de

    Graph-based analysis of brain connectivity during spelling task Mahmoud Hassan, Ahmad Mheich, the quantitative description of the topological organization of brain networks based on graph theory has received-Télécom) UMR CNRS Lab-STICC Brest, France firstname.name@telecom-bretagne.eu Abstract-- Most of the brain

  17. Task Delegation Based Access Control Models for Workflow Systems

    E-print Network

    Paris-Sud XI, Université de

    -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 Control (TAC) model based on RBAC to address these requirements. We aim to reason about task from

  18. Hybrid Heuristic-Based Artificial Immune System for Task Scheduling

    E-print Network

    sanei, Masoomeh

    2011-01-01

    Task scheduling problem in heterogeneous systems is the process of allocating tasks of an application to heterogeneous processors interconnected by high-speed networks, so that minimizing the finishing time of application as much as possible. Tasks are processing units of application and have precedenceconstrained, communication and also, are presented by Directed Acyclic Graphs (DAGs). Evolutionary algorithms are well suited for solving task scheduling problem in heterogeneous environment. In this paper, we propose a hybrid heuristic-based Artificial Immune System (AIS) algorithm for solving the scheduling problem. In this regard, AIS with some heuristics and Single Neighbourhood Search (SNS) technique are hybridized. Clonning and immune-remove operators of AIS provide diversity, while heuristics and SNS provide convergence of algorithm into good solutions, that is balancing between exploration and exploitation. We have compared our method with some state-of-the art algorithms. The results of the experiments...

  19. 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

  20. Verification duty policy for task-role-based workflow systems

    NASA Astrophysics Data System (ADS)

    Dong, Honglin; Liu, Yiliang; Huang, Qin; Yang, Tianyi; Ma, Fang

    2010-01-01

    A broad literature review presents great interests about theoretical specification or various formalizations on the constraints of Separation of Duty (SoD) Policy, which can improve Role-Based Access Control (RBAC). To gain the flexible and specific access control of information exchange within the enterprise environment, the proposed verification algorithm can check whether or not the Task-Role-Based Access Control (TRBAC) state can be satisfied with an assigned type of SoD policy, according to different given role-task and user-role assignments.

  1. Verification duty policy for task-role-based workflow systems

    NASA Astrophysics Data System (ADS)

    Dong, Honglin; Liu, Yiliang; Huang, Qin; Yang, Tianyi; Ma, Fang

    2009-12-01

    A broad literature review presents great interests about theoretical specification or various formalizations on the constraints of Separation of Duty (SoD) Policy, which can improve Role-Based Access Control (RBAC). To gain the flexible and specific access control of information exchange within the enterprise environment, the proposed verification algorithm can check whether or not the Task-Role-Based Access Control (TRBAC) state can be satisfied with an assigned type of SoD policy, according to different given role-task and user-role assignments.

  2. An Optimized Algorithm for Task Scheduling Based on Activity Based Costing in Cloud Computing

    Microsoft Academic Search

    Qi Cao; Zhi-Bo Wei; Wen-Mao Gong

    2009-01-01

    In cloud computing, traditional way for task scheduling cannot measure the cost of cloud resources accurately by reason that each of the tasks on cloud systems is totally different between each other. There may be no relationship between the overhead application base and the way that different tasks cause overhead costs of resources in cloud systems. The traditional way for

  3. Adaptive multi-task monitoring system based on overhead prediction

    Microsoft Academic Search

    Imed Lassoued; Chadi Barakat

    2010-01-01

    The remarkable growth of the Internet infrastructure, the tremendous success of the Internet-based applications and their rapidly changing characteristics have made the management and monitoring of ISP networks a complex process. The design of a new monitoring system that takes into account the requirements of multiple monitoring tasks and variations in the traffic is becoming an inevitable trend. In this

  4. PHOSPHORUS: A Task-Based Agent Matchmaker Yolanda Gil

    E-print Network

    Gil, Yolanda

    PHOSPHORUS: A Task-Based Agent Matchmaker Yolanda Gil Information Sciences Institute University, U.S.A. surya@isi.edu ABSTRACT PHOSPHORUS is an agent matchmaking service that exploits do- main of accomplishing, as well as requests to locate agents with a required capability. PHOSPHORUS supports match- ing

  5. A Task-Based Evaluation of an Aggregated Search Interface

    E-print Network

    Lalmas, Mounia

    . Federated search, distributed information retrieval, and metasearch engines are the techniques that aimA Task-Based Evaluation of an Aggregated Search Interface Shanu Sushmita, Hideo Joho, and Mounia that evaluated the effective- ness of an aggregated search interface in the context of non-navigational search

  6. 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…

  7. Data fusion for robotic assembly tasks based on human skills

    Microsoft Academic Search

    Rui Cortesão; Ralf Koeppe; Urbano Nunes; Gerd Hirzinger

    2004-01-01

    This work describes a data fusion architecture for robotic assembly tasks based on human sensory-motor skills. These skills are transferred to the robot through geometric and dynamic perception signals. Artificial neural networks are used in the learning process. The data fusion paradigm is addressed. It consists of two independent modules for optimal fusion and filtering. Kalman techniques linked to stochastic

  8. 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.

  9. 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.

  10. NEGATIVE FEEDBACK AND POSITIVE EVIDENCE IN TASK-BASED INTERACTION

    Microsoft Academic Search

    Noriko Iwashita

    2003-01-01

    This study examines the role of task-based conversation in second language (L2) grammatical development, focusing on the short-term effects of both negative feedback and positive evidence on the ac- quisition of two Japanese structures. The data are drawn from 55 L2 learners of Japanese at a beginning level of proficiency in an Austra- lian tertiary institution. Five different types of

  11. MLP based hierarchical system for task adaptation in ASR

    Microsoft Academic Search

    Joel Pinto; M. Magimai-Doss; Herv ´ e Bourlard

    2009-01-01

    We investigate a multilayer perceptron (MLP) based hierarchical approach for task adaptation in automatic speech recognition. The system consists of two MLP classifiers in tandem. A well-trained MLP available off-the-shelf is used at the first stage of the hierarchy. A second MLP is trained on the posterior features estimated by the first, but with a long temporal context of around

  12. 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

    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/h 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, and 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

  13. The Nature of Impulsivity: Visual Exposure to Natural Environments Decreases Impulsive Decision-Making in a Delay Discounting Task

    PubMed Central

    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

  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. 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.

  16. Machine Learning based Work Task Classification Michael Granitzer

    E-print Network

    Boyer, Edmond

    and provides data for the machine learning system TaskPredic- tor [14]. Three major processing steps and studying their predictability for specific task types in web browsers. While previous work demonstrated

  17. Nanotechnology-based electrochemical sensors for biomonitoring chemical exposures

    Microsoft Academic Search

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

    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 (EC) sensors has the potential to meet the needs for low cost, rapid, high-throughput, and

  18. 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

  19. 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…

  20. Gradient Field-Based Task Assignment in an AGV Transportation System

    Microsoft Academic Search

    Danny Weyns; Nelis Boucké; Tom Holvoet; Wannes Schols

    2005-01-01

    Assigning tasks to agents is complex, especially in highly dynamic environments. Typical protocol-based approaches for task assign- ment such as Contract Net have proven their value, however, they may not be flexible enough to cope with continuously changing cir- cumstances. In this paper we study and validate the feasibility of a field-based approach for task assignment in a complex problem

  1. 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…

  2. 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

  3. Implementing Task-based Teaching from the Ground Up: Considerations for Lesson Planning and Classroom Practice

    E-print Network

    Comer, William J.

    2007-01-01

    After synthesizing the scholarly literature on what makes a task in language teaching, the author presents a detailed look at one implementation of task-based language teaching in an beginning-level Russian language classroom. Appendices include...

  4. Implicit sequence learning based on instructed task set.

    PubMed

    Gaschler, Robert; Frensch, Peter A; Cohen, Asher; Wenke, Dorit

    2012-09-01

    How does the way we code and control actions influence automatic skill acquisition processes? Wenke and Frensch (2005) showed that instructions can lead participants to code spatial responses based on color. Here, we tested in 3 experiments to what extent response labeling and instruction-based response coding can determine what is learned in implicit sequence learning. Instructions mapped 4 gray shape stimuli to 1 of the 4 keys each in a serial reaction task, referring to the keys in terms of either their color or their spatial location. In Experiments 1 and 2 we found that people in the color instruction conditions used color for action control and acquired sequence knowledge containing color: They were susceptible to irrelevant stimulus colors at transfer and could transfer color sequence knowledge to a new arrangement of response positions and fingers, whereas participants who had received spatial instructions could not. Implicit sequence learning was thus surprisingly flexible. Depending on whether an arbitrary nonspatial response feature was used or not used to explain the stimulus-response mappings, we either found or did not find evidence that this feature became part of action control and sequence learning. Furthermore, Experiment 3 suggested that response position might become part of the sequence knowledge even if instructions do not emphasize this response feature. Together, the findings suggest that implicit sequence learning is based on action control, which in turn strongly, but not entirely, depends on which response features are used to explain the stimulus-response mappings in the instructions. PMID:22545612

  5. Executive brain functions after exposure to nocturnal traffic noise: effects of task difficulty and sleep quality

    Microsoft Academic Search

    Sergei A. Schapkin; Michael Falkenstein; Anke Marks; Barbara Griefahn

    2006-01-01

    The after-effects of nocturnal traffic noise on cognitive performance and inhibitory brain activity were investigated. Twenty\\u000a participants (18–30 years) performed an easy and a difficult visual Go\\/Nogo task with simultaneous EEG recording after a quiet\\u000a night and then during three nights when aircraft noise was presented with equivalent noise levels of 39, 44, and 50 dBA, respectively,\\u000a between 11 p.m. to 7

  6. Task-dependent neural bases of perceiving emotionally expressive targets

    PubMed Central

    Zaki, Jamil; Weber, Jochen; Ochsner, Kevin

    2012-01-01

    Social cognition is fundamentally interpersonal: individuals' behavior and dispositions critically affect their interaction partners' information processing. However, cognitive neuroscience studies, partially because of methodological constraints, have remained largely “perceiver-centric”: focusing on the abilities, motivations, and goals of social perceivers while largely ignoring interpersonal effects. Here, we address this knowledge gap by examining the neural bases of perceiving emotionally expressive and inexpressive social “targets.” Sixteen perceivers were scanned using fMRI while they watched targets discussing emotional autobiographical events. Perceivers continuously rated each target's emotional state or eye-gaze direction. The effects of targets' emotional expressivity on perceiver's brain activity depended on task set: when perceivers explicitly attended to targets' emotions, expressivity predicted activity in neural structures—including medial prefrontal and posterior cingulate cortex—associated with drawing inferences about mental states. When perceivers instead attended to targets' eye-gaze, target expressivity predicted activity in regions—including somatosensory cortex, fusiform gyrus, and motor cortex—associated with monitoring sensorimotor states and biological motion. These findings suggest that expressive targets affect information processing in manner that depends on perceivers' goals. More broadly, these data provide an early step toward understanding the neural bases of interpersonal social cognition. PMID:22876229

  7. Load balancing in parallel and distributed processing of tree-based multiple-task jobs

    Microsoft Academic Search

    Leszek Borzemski

    1995-01-01

    The efficient processing of tree based multiple task jobs arriving in batches to parallel and distributed systems is presented. This type of processing can be found in such application fields as, for example, automatic diagnostics and document recognition. A key management issue in such systems is task allocation. Load balancing is often proposed as the task allocation approach. The load

  8. Task-Level Data Model for Hardware Synthesis Based on Concurrent Collections

    E-print Network

    Cong, Jason "Jingsheng"

    design flow. Based on the Concurrent Collection (CnC) model, which provides the maximum freedom of task rescheduling, we propose a customized variation of CnC named task-level data model (TLDM), targeted at the task, programmable cores and memory hierarchies. The sequential C/C++ programming language has inherent limitations

  9. 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,…

  10. A Task Scheduling Algorithm Based on PSO for Grid Computing

    Microsoft Academic Search

    Lei Zhang; Yuehui Chen; Runyuan Sun; Shan Jing

    2008-01-01

    Grid computing is a high performance computing environment to solve larger scale computational demands. Grid computing contains resource management, task scheduling, security problems, information management and so on. Task scheduling is a fundamental issue in achieving high performance in grid computing systems. However, it is a big challenge for efficient scheduling algorithm design and implementation. In this paper, a heuristic

  11. BDI-based generation of robust task-oriented dialogues

    Microsoft Academic Search

    N. L. Vergunst

    2011-01-01

    Planning dialogues is a notoriously difficult task, consisting of several non-trivial components. Because of this, programming human-computer dialogues is also a complicated task. Humans are unpredictable, make mistakes, vary their pronunciation, change their minds halfway through utterances or actions, and so on. Although not all errors can be solved easily, we can at least attempt to avoid total communication breakdown.

  12. 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 ?g/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

  13. 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.

  14. 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…

  15. 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

  16. Lifting task design associate: a knowledge-based system 

    E-print Network

    Brooks, Susan Elaine

    1993-01-01

    States workforce is compensated at some point during their career for an injury caused by poor job design (Schaffer, 1982) Manual material handler (MMH) groups are susceptible to many types of injuries. Estimates as high as 1 of every 4 reported... concern for two reasons, the liAing task makes up the largest proportion of the MMH tasks and lifting injuries frequently results in low back injuries (Alexander, 1986, Sanders and McCormick, 1987). Although back injuries account for few work...

  17. 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

  18. A novel boosting algorithm for multi-task learning based on the Itakuda-Saito divergence

    NASA Astrophysics Data System (ADS)

    Takenouchi, Takashi; Komori, Osamu; Eguchi, Shinto

    2015-01-01

    In this paper, we propose a novel multi-task learning algorithm based on an ensemble learning method. We consider a specific setting of the multi-task learning for binary classification problems, in which features are shared among all tasks and all tasks are targets of performance improvement. We focus on a situation that the shared structures among dataset are represented by divergence between underlying distributions associated with multiple tasks. We discuss properties of the proposed method and investigate validity of the proposed method with numerical experiments.

  19. Gradient field-based task assignment in an AGV transportation system

    Microsoft Academic Search

    Danny Weyns; Nelis Boucké; Tom Holvoet

    2006-01-01

    ABSTRACT Assigning tasks to agents is complex, especially in highly dynamic environments. Typical protocol-based approaches for task assignment such as Contract Net have proven their value, however, they may,not be flexible enough,to cope with continuously changing circumstances. In this paper we study and validate the feasibility of a field-based approach,for task assignment,in a complex,problem domain. In particular, we apply the

  20. 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

  1. 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.

  2. Task-Model Based Human Robot Cooperation Using Vision 3 Hiroshi Kimura and Tomoyuki Horiuchi

    E-print Network

    Kimura, Hiroshi

    an experiment in which the human and the robotic hand assembled toy parts in cooperation. 1 Introduction the appropriate assistance motions according to the human motions based on task models (Fig.1-B). The experimentsTask-Model Based Human Robot Cooperation Using Vision 3 Hiroshi Kimura and Tomoyuki Horiuchi

  3. Trust-based Multi-Objective Optimization for Node-to-Task Assignment in Coalition Networks

    E-print Network

    Chen, Ing-Ray

    solution implemented with the Integer Linear Programming technique. Keywords--multi-objective optimizationTrust-based Multi-Objective Optimization for Node-to-Task Assignment in Coalition Networks Jin minimizing delay to task completion. We devise a ranking-based heuristic with linear runtime complexity

  4. Attitudes toward Task-Based Language Learning: A Study of College Korean Language Learners

    ERIC Educational Resources Information Center

    Pyun, Danielle Ooyoung

    2013-01-01

    This study explores second/foreign language (L2) learners' attitudes toward task-based language learning (TBLL) and how these attitudes relate to selected learner variables, namely anxiety, integrated motivation, instrumental motivation, and self-efficacy. Ninety-one college students of Korean as a foreign language, who received task-based

  5. 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...

  6. Low-level lead exposure and contingency-based responding in preschoolers: an exploratory study.

    PubMed

    Nelson, Melanie McDiarmid; Espy, Kimberly Andrews

    2009-01-01

    Two reversal paradigm tasks (spatial reversal and spatial reversal with irrelevant color cues) originally designed to assess contingency-based responding in primates were adapted for use with 139 preschool children with a mean peak blood lead level (BLL) of 4.2 microg/dl (SD = 2.2). Sixty-nine children with BLL > or =5 microg/dl and 70 children with BLL of <5 microg/dl were included. Results indicated that preschool children with low-level lead exposure take longer to learn associations than preschool children with very low levels of lead exposure, and this difference cannot be attributed to increased distractibility or perseverative responding. These results support the use of these measures to assess specific cognitive functions in preschool children. PMID:20183713

  7. Characteristic-Based, Task-Based, and Results-Based: Three Value Systems for Assessing Professionally Produced Technical Communication Products.

    ERIC Educational Resources Information Center

    Carliner, Saul

    2003-01-01

    Notes that technical communicators have developed different methodologies for evaluating the effectiveness of their work, such as editing, usability testing, and determining the value added. Explains that at least three broad value systems underlie the assessment practices: characteristic-based, task-based, and results-based. Concludes that the…

  8. 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…

  9. Force-Based Motion Editing for Locomotion Tasks

    Microsoft Academic Search

    Nancy S. Pollard; Fareed Behmaram-mosavat

    2000-01-01

    This paper describes a fast technique for modifying mo- tion sequences for complex articulated mechanisms in a way that preserves physical properties of the motion. This technique is relevant to the problem of teaching motion tasks by demonstration, because it allows a single exam- ple to be adapted to a range of situations. Motion may be obtained from any source;

  10. 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

  11. 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

  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. Chemical process-based reconstruction of exposures for an epidemiological study. Part II. Estimated exposures to chloroprene and vinyl chloride.

    PubMed

    Esmen, Nurtan A; Hall, Thomas A; Phillips, Margaret L; Jones, E Paige; Basara, Heather; Marsh, Gary M; Buchanich, Jeanine M

    2007-03-20

    In a four-facility occupational epidemiology study of chloroprene monomer and polymer production workers, the chloroprene (CD) and vinyl chloride monomer (VCM) exposures were modeled for plant specific job title classes. In two facilities an acetylene-based process was used and in the other two plants only a butadiene-based process was used in the monomer synthesis. In the Acetylene process VCM was an undesirable by-product to be removed. In the newer butadiene-based process, VCM was not involved and the exposures to CD were considerably lower than they were in the earlier years. One of the limiting factors was the operator rotation within a number of job titles. This rotation and inability to differentiate between job titles subsumed in job classifications recorded in the work histories required an exposure classification scheme based on an order of magnitude separation of exposure classes. In the four facilities with considerable variation in the mix of the production methods, the CD exposures were remarkably similar in both calculated and measured values. The reductions in exposures were much more dependent upon the improvement of the production methods, rather than deliberate exposure control for occupational hygiene considerations. This is reasonable since the exposures were generally lower than the coeval exposure limits and/or guidelines. The estimated exposures were less than 100 ppm in the pre-1960 era and less than 10 ppm in the 1960-1980 era, less than 1 ppm 1980-1990 era and less than 0.5 ppm thereafter. The exposures were categorized in four classes for VCM and six classes for CD. The characteristic class exposure values were used to cumulate individual exposures over time with a quantification of the potential range for exposures that are reasonably certain to ascribe correct ranking to job classes. PMID:16989794

  14. 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…

  15. 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…

  16. Agent-Based Grid Load Balancing Using Performance-Driven Task Scheduling Junwei Cao*1

    E-print Network

    Jarvis, Stephen

    Agent-Based Grid Load Balancing Using Performance-Driven Task Scheduling Junwei Cao*1 , Daniel P This work was carried out when the author was with the University of Warwick. Abstract Load balancing-driven task scheduler that has been developed for local grid load balancing. Each grid scheduler utilises

  17. Interactive Computer Based Assessment Tasks: How Problem-Solving Process Data Can Inform Instruction

    ERIC Educational Resources Information Center

    Zoanetti, Nathan

    2010-01-01

    This article presents key steps in the design and analysis of a computer based problem-solving assessment featuring interactive tasks. The purpose of the assessment is to support targeted instruction for students by diagnosing strengths and weaknesses at different stages of problem-solving. The first focus of this article is the task piloting…

  18. How Second Language Learners Respond to Central and Peripheral Content-Based Tasks.

    ERIC Educational Resources Information Center

    Berwick, Richard

    A study investigated the use of content-based tasks as central and peripheral in second language instruction. Specifically, it examined the relative effects of such tasks that were either central to the syllabus, as sources of knowledge or skills in their own right, or peripheral, as occasional source of language practice. The study was conducted…

  19. Case-Based Tasks in Mathematics Teacher Preparation: What Is Appropriate?

    ERIC Educational Resources Information Center

    Manouchehri, Azita; Almohalwas, Akram

    2008-01-01

    This article describes a framework for selecting and designing case-based tasks suitable for professional development of mathematics teachers in order for such tasks to lead to substantial learning. The authors share an example they designed and used in content courses and give an account of the impact on their work and on students' learning.…

  20. School-Based Collaborative Teams: An Exploratory Study of Tasks and Activities

    ERIC Educational Resources Information Center

    Phillippo, Kate; Stone, Susan

    2006-01-01

    This study reports findings from a content analysis of the activities and tasks of a school-based problem-solving team. Analyses of observational data collected over the course of five months found that team tasks and activities fell into the following five clusters: (1) needs identification, program development, and planning; (2) intrateam…

  1. 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…

  2. Integrating Model-Based and Task-Based Approaches to User Interface Generation

    NASA Astrophysics Data System (ADS)

    España, Sergio; Pederiva, Inés; Panach, Jose Ignacio

    Software Engineering community has been interested in defining methods and processes to develop software by specifying its data and behavior, but disregarding user interaction. Human-Computer Interaction community has defined techniques oriented to the modeling of the interaction between the user and the system, proposing user-oriented software constructions. In this paper, we show how to lay proper bridges between both visions, by integrating a CTT task model into a sound, model-based software development process. This proposal is underpinned by the MDA-based technology OlivaNova Method Execution, which makes software generation a reality, while still taking the user interaction needs into account

  3. 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.

  4. 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.

  5. SBL-based multi-task algorithms for recovering block-sparse signals with unknown partitions

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    We consider in this paper the problem of reconstructing block-sparse signals with unknown block partitions. In the first part of this work, we extend the block-sparse Bayesian learning (BSBL) originally developed for recovering a single block-sparse signal in a single compressive sensing (CS) task scenario to the case of multiple CS tasks. A new multi-task signal recovery algorithm, called the extended multi-task block-sparse Bayesian learning (EMBSBL), is proposed. EMBSBL exploits the statistical correlation among multiple signals as well as the intra-block correlation within individual signals to improve performance. Besides, it does not need a priori information on block partition. As the second part of this paper, we develop the EMBSBL-based synthesized multi-task signal recovery algorithm, namely SEMBSBL, to make it applicable to the single CS task case. The idea is to synthesize new CS tasks from the single CS task via circular-shifting operations and utilizes the minimum description length principle to determine the proper set of the synthesized CS tasks for signal reconstruction. SEMBSBL can achieve better signal reconstruction performance over other algorithms that recover block-sparse signals individually. Simulations corroborate the theoretical developments.

  6. Injecting Task Delegation Constraints into a Role-based Access Control Model

    E-print Network

    Paris-Sud XI, Université de

    -based access control (RBAC) model is widely adopted, where system administrators assign roles to users extend the RBAC model of Sandhu et al. in two directions: (i) our formal security model defines a Task

  7. Mining knowledge flow for modeling the information needs of task-based groups

    Microsoft Academic Search

    Chin-hui Lai; Duen-ren Liu

    2008-01-01

    Knowledge is the most important resource to create core competitive advantages for an organization. Such knowledge is circulated and accumulated by a knowledge flow (KF) in an organization to support worker’s tasks. Workers may cooperate and participate in several task-based groups to fulfill their needs. In this paper, we propose a group-based knowledge flow mining algorithm which integrates information retrieval

  8. 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.

  9. A field-based versus a protocol-based approach for adaptive task assignment

    Microsoft Academic Search

    Danny Weyns; Nelis Boucké; Tom Holvoet

    2008-01-01

    Task assignment in multi-agent systems is a complex coordination problem, in particular in systems that are subject to dynamic and changing operating conditions. To enable agents to deal with dynamism and change, adaptive task assignment approaches are needed. In this paper, we study two approaches for adaptive task assignment that are characteristic for two classical families of task assignment approaches.

  10. 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

  11. Task Based Automatic Examination System for Sequenced Test

    Microsoft Academic Search

    Song Luo; Jianbin Hu; Zhong Chen

    2009-01-01

    Computer greatly influences our educational environment. Over the last years, automatic computer examination systems have been widely used for computer-based tests. But these systems are based on traditional question-answer examination style which is not fit for the sequenced test. The sequenced test should consider the context of the examinee, e.g. the order of questions or the permissions of the examinee,

  12. Algorithm Design of CPCI Backboard's Interrupts Management Based on VxWorks' Multi-Tasks

    Microsoft Academic Search

    Jingyuan Cheng; Qi An; Junfeng Yang

    2006-01-01

    This paper begins with a brief introduction of the embedded real-time operating system VxWorks and CompactPCI standard, then gives the programming interfaces of Peripheral Controller Interface (PCI) configuring, interrupts handling and multi-tasks programming interface under VxWorks, and then emphasis is placed on the software frameworks of CPCI interrupt management based on multi-tasks. This method is sound in design and easy

  13. 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.

  14. Behavioral Features for Different Haptic-based Biometric Tasks

    Microsoft Academic Search

    R. Iglesias; M. Orozco; J. J. Valdes; A. El Saddik

    2007-01-01

    The science of haptics or haptic technology has received enormous attention in the last decade for multiple applications. A new promising example is the use of haptic-based systems for individual authentication. A user 's behavioral characteristics captured while interacting with a virtual scene are significantly more difficult to compromise than traditional means (i.e. login ID and passwords). Moreover, another advantage

  15. Sparse representation of higher-order functional interaction patterns in task-based FMRI data.

    PubMed

    Zhang, Shu; Li, Xiang; Lv, Jinglei; Jiang, Xi; Zhu, Dajiang; Chen, Hanbo; Zhang, Tuo; Guo, Lei; Liu, Tianming

    2013-01-01

    Traditional task-based fMRI activation detection methods, e.g., the widely used general linear model (GLM), assume that the brain's hemodynamic responses follow the block-based or event-related stimulus paradigm. Typically, these activation detections are performed voxel-wise independently, and then are usually followed by statistical corrections. Despite remarkable successes and wide adoption of these methods, it remains largely unknown how functional brain regions interact with each other within specific networks during task performance blocks and in the baseline. In this paper, we present a novel algorithmic pipeline to statistically infer and sparsely represent higher-order functional interaction patterns within the working memory network during task performance and in the baseline. Specifically, a collection of higher-order interactions are inferred via the greedy equivalence search (GES) algorithm for both task and baseline blocks. In the next stage, an effective online dictionary learning algorithm is utilized for sparse representation of the inferred higher-order interaction patterns. Application of this framework on a working memory task-based fMRI data reveals interesting and meaningful distributions of the learned sparse dictionary atoms in task and baseline blocks. In comparison with traditional voxel-wise activation detection and recent pair-wise functional connectivity analysis, our framework offers a new methodology for representation and exploration of higher-order functional activities in the brain. PMID:24505814

  16. 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.

  17. Mobile Task Computing: Beyond Location-Based Services and EBooks

    Microsoft Academic Search

    John Liagouris; Spiros Athanasiou; Alexandros Efentakis; Stefan Pfennigschmidt; Dieter Pfoser; Eleni Tsigka; Agnès Voisard

    2010-01-01

    \\u000a Mobile devices are a promising platform for content delivery considering the (i) variety of attached sensors, (ii) widespread\\u000a availability of wireless networks, (iii) even increasing screen estate and hardware specs. What has been missing so far is\\u000a the adequate coupling of content to those devices and their users’ actions. This is especially apparent in the area of Location-based\\u000a Services (LBS),

  18. Focal putamen lesions impair learning in rule-based, but not information-integration categorization tasks.

    PubMed

    Ell, Shawn W; Marchant, Natalie L; Ivry, Richard B

    2006-01-01

    Previous research on the role of the basal ganglia in category learning has focused on patients with Parkinson's and Huntington's disease, neurodegenerative diseases frequently accompanied by additional cortical pathology. The goal of the present study was to extend this work to patients with basal ganglia lesions due to stroke, asking if similar changes in performance would be observed in patients with more focal pathology. Patients with basal ganglia lesions centered in the putamen (6 left side, 1 right side) were tested on rule-based and information-integration visual categorization tasks. In rule-based tasks, it is assumed that participants can learn the category structures through an explicit reasoning process. In information-integration tasks, optimal performance requires the integration of information from two or more stimulus components, and participants are typically unaware of the category rules. Consistent with previous studies involving patients with degenerative disorders of the basal ganglia, the stroke patients were impaired on the rule-based task, and quantitative, model-based analyses indicate that this deficit was due to the inefficient application of decision strategies. In contrast, the patients were unimpaired on the information-integration task. This pattern of results provides converging evidence supporting a role of the basal ganglia and, in particular, the putamen in rule-based category learning. PMID:16635498

  19. 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.

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

    PubMed

    Jurewicz, Joanna; Radwan, Micha?; Sobala, Wojciech; Radwan, Pawe?; Bochenek, Micha?; 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

  1. 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

  2. Evaluating Tasks for Performance-Based Assessments: Advice for Music Teachers

    ERIC Educational Resources Information Center

    Scott, Sheila

    2004-01-01

    Performance-based assessments allow teachers to systematically observe skills used or demonstrated by students when they create a product, construct a response, or make a presentation (McMillan 2001). These assessments are grounded in performance-based tasks that elicit students' responses in relation to the outcomes of instruction. The criteria…

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. Effects of acceptance-based coping on task performance and subjective stress.

    PubMed

    Kishita, Naoko; Shimada, Hironori

    2011-03-01

    This paper examines the interactive effects of acceptance-based coping and job control on task performance, subjective stress, and perceived control. Forty-eight undergraduate and graduate students first participated in brief educational programs based on either acceptance or control coping strategies. They then participated in a 30-min high workload task under either high or low job control conditions. The results demonstrated a significant interactive effect of acceptance-based coping and job control on perceived control and task performance. No such effect was found for subjective stress. We conclude that to improve employees' perceived control and job performance, there should be an increase not only in job control through work redesign, but also in psychological acceptance. PMID:21074000

  8. Sensory-guided motor tasks benefit from mental training based on serial prediction.

    PubMed

    Binder, Ellen; Hagelweide, Klara; Wang, Ling E; Kornysheva, Katja; Grefkes, Christian; Fink, Gereon R; Schubotz, Ricarda I

    2014-02-01

    Mental strategies have been suggested to constitute a promising approach to improve motor abilities in both healthy subjects and patients. This behavioural effect has been shown to be associated with changes of neural activity in premotor areas, not only during movement execution, but also while performing motor imagery or action observation. However, how well such mental tasks are performed is often difficult to assess, especially in patients. We here used a novel mental training paradigm based on the serial prediction task (SPT) in order to activate premotor circuits in the absence of a motor task. We then tested whether this intervention improves motor-related performance such as sensorimotor transformation. Two groups of healthy young participants underwent a single-blinded five-day cognitive training schedule and were tested in four different motor tests on the day before and after training. One group (N=22) received the SPT-training and the other one (N=21) received a control training based on a serial match-to-sample task. The results revealed significant improvements of the SPT-group in a sensorimotor timing task, i.e. synchronization of finger tapping to a visually presented rhythm, as well as improved visuomotor coordination in a sensory-guided pointing task compared to the group that received the control training. However, mental training did not show transfer effects on motor abilities in healthy subjects beyond the trained modalities as evident by non-significant changes in the Jebsen-Taylor handfunctiontest. In summary, the data suggest that mental training based on the serial prediction task effectively engages sensorimotor circuits and thereby improves motor behaviour. PMID:24321273

  9. Toward open sharing of task-based fMRI data: the OpenfMRI project

    PubMed Central

    Poldrack, Russell A.; Barch, Deanna M.; Mitchell, Jason P.; Wager, Tor D.; Wagner, Anthony D.; Devlin, Joseph T.; Cumba, Chad; Koyejo, Oluwasanmi; Milham, Michael P.

    2013-01-01

    The large-scale sharing of task-based functional neuroimaging data has the potential to allow novel insights into the organization of mental function in the brain, but the field of neuroimaging has lagged behind other areas of bioscience in the development of data sharing resources. This paper describes the OpenFMRI project (accessible online at http://www.openfmri.org), which aims to provide the neuroimaging community with a resource to support open sharing of task-based fMRI studies. We describe the motivation behind the project, focusing particularly on how this project addresses some of the well-known challenges to sharing of task-based fMRI data. Results from a preliminary analysis of the current database are presented, which demonstrate the ability to classify between task contrasts with high generalization accuracy across subjects, and the ability to identify individual subjects from their activation maps with moderately high accuracy. Clustering analyses show that the similarity relations between statistical maps have a somewhat orderly relation to the mental functions engaged by the relevant tasks. These results highlight the potential of the project to support large-scale multivariate analyses of the relation between mental processes and brain function. PMID:23847528

  10. 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.

  11. 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.

  12. Modelling framework for assessment of dietary exposure to added flavouring substances within the FACET (Flavours, Additives, and Food Contact Material Exposure Task) project.

    PubMed

    Mistura, Lorenza; Sette, Stefania; O'Mahony, Cian; Engel, Karl-Heinz; Mehegan, John; Leclercq, Catherine

    2013-08-01

    This paper provides a model to assess dietary exposure to flavouring substances intentionally added to food. The purpose is to describe the approaches currently available and their scientific basis. The proposed exposure model for flavouring substances envisages three different levels of refinement: basic, intermediate and refined. At the two first levels, the model may be applied to all 2543 substances actually in use in Europe, while the refined level has been applied to 41 target flavouring substances selected within the FACET project. The refined level entails the use of the probability of addition of the flavouring substance added to the food and of correction factors related to losses owing to the processing of a food. PMID:23639587

  13. 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,…

  14. Memory in the Small: An Application to Provide Task-Based Organizational Memory for a Scientific Community

    E-print Network

    Ackerman, Mark S.

    Memory in the Small: An Application to Provide Task-Based Organizational Memory for a Scientific of organizational memory must exist embedded within the organizational processes and tasks. This paper argues that "memory-in-the small," memory utilized in the performance of an organizational task, can serve

  15. Task analysis and rationale for a performance based consultative sales training program for electric utility customer engineers

    Microsoft Academic Search

    1985-01-01

    A job task analysis was performed to determine the major tasks and specific competencies required of electric power company customer engineers in a changing economic and technological climate. Through an examination of occupational documents, interviews with occupational specialists, and a questionnaire completed by an electric utility company focus group, 13 major customer tasks and 222 specific competencies were identified. Based

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

    NASA Astrophysics Data System (ADS)

    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.

  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. Chemical process based reconstruction of exposures for an epidemiological study. III. Analysis of industrial hygiene samples.

    PubMed

    Hall, Thomas A; Esmen, Nurtan A; Jones, Elizabeth P; Basara, Heather; Phillips, Margaret L; Marsh, Gary M; Youk, Ada O; Buchanich, Jeanine M; Leonard, Robin C

    2007-03-20

    As part of an historical cohort study to investigate the mortality experience of industrial workers exposed to chloroprene (beta-CD) and other substances, all available industrial hygiene exposure monitoring data were collected and summarized. From discussions with on-site industrial hygiene personnel, it was apparent that these data were not collected for epidemiological purposes and, therefore, their use in characterization of exposures was problematic as the data mostly pertained to samples collected to investigate the performance of specific tasks. These data were, however, informative for validating the exposure modeling process used to estimate historical exposures. The data summarized below clearly indicate that exposures to beta-CD were lowered across the time period of this study. Typically, the exposures recorded were less than the occupational exposure limits of the periods in which the exposures were recorded. Additionally, exposure measurements recorded in the recent past do not represent the exposure actually experienced by the worker as a strict personal protective equipment use program has been in place for the facilities studied since the mid-1980s. PMID:17074311

  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.

  20. 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…

  1. Does head-only exposure to GSM900 electromagnetic fields affect the performance of rats in spatial learning tasks?

    Microsoft Academic Search

    Diane Dubreuil; Thérèse Jay; Jean-Marc Edeline

    2002-01-01

    The rapid expansion of mobile communication has generated intense interest, but has also fuelled ongoing concerns. In both humans and animals, radiofrequency radiations are suspected to affect cognitive functions. More specifically, several studies performed in rodents have suggested that spatial learning can be impaired by electromagnetic field exposure. However, none of these previous studies have simulated the common conditions of

  2. What Effects do Text-Based Tasks Promoting Generation Have on Incidental Vocabulary Acquisition?

    ERIC Educational Resources Information Center

    Joe, Angela

    1998-01-01

    Examined the effects of text-based tasks and background knowledge on incidental vocabulary acquisition among adult English-as-a-Second-Language-learners who received treatments involving reading and retelling text with or without generative training. Pretesting and posttesting indicated that reading and retelling promoted incidental vocabulary…

  3. Learning by Observation of Robotic Tasks using On-line PCA-based Eigen Behavior *

    E-print Network

    Motai, Yuichi

    Learning by Observation of Robotic Tasks using On-line PCA-based Eigen Behavior * Xianhua Jiang. Abstract - This paper presents a new framework for learning the behavior of an articulated body. The motion. Index Terms - incremental learning, motion analysis, principal component analysis, behavior editor

  4. 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…

  5. 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…

  6. Task-Based Trajectory Optimization in Musculoskeletal Systems Antonie J. (Ton) van den Bogert, 2

    E-print Network

    Sanderson, Yasmine

    Task-Based Trajectory Optimization in Musculoskeletal Systems 1 Antonie J. (Ton) van den Bogert, 2 musculoskeletal dynamics as well as behavioral principles for control. 2 State of the Art To solve the human believe that the strong nonlinearity of musculoskeletal dynamics, including the foot-ground contact model

  7. Task Listing for Piano Technology for the Visually Impaired. Competency-Based Education.

    ERIC Educational Resources Information Center

    Virginia State Dept. of Education, Richmond. Div. of Vocational and Adult Education.

    This task listing was developed for use in Piano Technology, a course offered to visually impaired students at the Virginia School for the Deaf and Blind. The listing is intended to be used with the "Trade and Industrial Education Service Area Resource Guide" in the implementation of competency-based education for this population. The major…

  8. Toward Task-Based Mental Models of Human-Robot Teaming: A Bayesian Approach

    E-print Network

    Goodrich, Michael A.

    Toward Task-Based Mental Models of Human-Robot Teaming: A Bayesian Approach Michael A. Goodrich1 rather than a tool [2]. In this team-centered approach, both humans and robots can take on roles is correlated. In a human-robot team, the asymmetries on abilties and information mostly come from the natural

  9. Merging Foreign Language Theory and Practice in Designing Technology-Based Tasks

    Microsoft Academic Search

    Lara Lomicka; Melanie Manzer

    While educators are aware of the benefits of technology in language instruction, one challenge they face is how to implement effective interactive technology-based tasks. Technology offers numerous advantages, yet it is not without some drawbacks. Terry (1998) notes the purpose of using technology should be clear and pedagogical; it should not be used \\

  10. Task Analysis of the Job Description of Gerontological Nurse Practitioners based on DACUM

    Microsoft Academic Search

    Keum Soon

    1 Park, Yeon-Hwan 2 Purpose: The aim of this study was to develop and to analyze the task of gerontological nurse practitioners (GNPs) in Korea. Methods: The definition of GNP and job description was developed based on developing a curriculum (DACUM) by 7 panels who have experienced in DACUM analysis and gerontological nursing. One hundred sixty nurses who were working

  11. Communicative task modeling and its practice on academic English learning in a web-based environment

    Microsoft Academic Search

    Jin Chen; Alexandra Cristea; Toshio Okamoto

    2003-01-01

    A web-based course for scholarly communicative language competence development via a distance tutoring system is presented. Particular focus is given to the description of the representation and organization of communicative tasks representing the subject matter knowledge in terms of communicative-goal, input for achieving this goal and activity derived from this input. Moreover, the link relations among the three knowledge structures

  12. Algorithm Design of CPCI Backboard's Interrupts Management Based on VxWorks' Multi-Tasks

    NASA Astrophysics Data System (ADS)

    Cheng, Jingyuan; An, Qi; Yang, Junfeng

    2006-09-01

    This paper begins with a brief introduction of the embedded real-time operating system VxWorks and CompactPCI standard, then gives the programming interfaces of Peripheral Controller Interface (PCI) configuring, interrupts handling and multi-tasks programming interface under VxWorks, and then emphasis is placed on the software frameworks of CPCI interrupt management based on multi-tasks. This method is sound in design and easy to adapt, ensures that all possible interrupts are handled in time, which makes it suitable for data acquisition systems with multi-channels, a high data rate, and hard real-time high energy physics.

  13. Rule-based extraction of experimental evidence in the biomedical domain: the KDD Cup 2002 (task 1)

    Microsoft Academic Search

    Yizhar Regev; Michal Finkelstein-Landau; Ronen Feldman; Maya Gorodetsky; Xin Zheng; Samuel Levy; Rosane Charlab; Charles Lawrence; Ross A. Lippert; Qing Zhang; Hagit Shatkay

    2002-01-01

    Below we describe the winning system that we built for the KDD Cup 2002 Task 1 competition. Our system is a Rule-based Information Extraction (IE) system. It combines pattern matching, Natural Language Processing (NLP) tools, semantic constraints based on the domain and the specific task, and a post-processing stage for making the final curation decision based on the various evidence

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

    SciTech Connect

    Bornefalk, Hans [Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm (Sweden)

    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.

  15. Analysis of radiation exposure for Task Force Big Bang, Shot Galileo. Exercise Desert Rock VII-VIII Operation Plumbbob. Final report, 27 February 1978-19 July 1979

    Microsoft Academic Search

    J. L. Goetz; D. Kaul; J. Klemm; J. T. McGahan; W. K. McRaney

    1980-01-01

    The radiation doses to Task Force BIG BANG troops who participated in Shot GALILEO are determined and compared with film badge data gathered during Exercise Desert Rock VII-VIII. Fallout contours and decay rates, are established and used to calculate total external beta and gamma doses, based on estimated stay time for various troop activities. Uncertainties are calculated for each parameter.

  16. Performance Monitoring and Analysis of Task-Based OpenMP

    PubMed Central

    Ding, Yi; Hu, Kai; Wu, Kai; Zhao, Zhenlong

    2013-01-01

    OpenMP, a typical shared memory programming paradigm, has been extensively applied in high performance computing community due to the popularity of multicore architectures in recent years. The most significant feature of the OpenMP 3.0 specification is the introduction of the task constructs to express parallelism at a much finer level of detail. This feature, however, has posed new challenges for performance monitoring and analysis. In particular, task creation is separated from its execution, causing the traditional monitoring methods to be ineffective. This paper presents a mechanism to monitor task-based OpenMP programs with interposition and proposes two demonstration graphs for performance analysis as well. The results of two experiments are discussed to evaluate the overhead of monitoring mechanism and to verify the effects of demonstration graphs using the BOTS benchmarks. PMID:24204946

  17. 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

  18. Task-based evaluation of practical lens designs for lens-coupled digital mammography systems

    NASA Astrophysics Data System (ADS)

    Chen, Liying; Foo, Leslie D.; Cortesi, Rebecca L.; Thompson, Kevin P.; Barrett, Harrison H.

    2007-03-01

    Recent developments in low-noise, large-area CCD detectors have renewed interest in radiographic systems that use a lens to couple light from a scintillation screen to a detector. The lenses for this application must have very large numerical apertures and high spatial resolution over a FOV. This paper expands on our earlier work by applying the principles of task-based assessment of image quality to development of meaningful figures of merit for the lenses. The task considered in this study is detection of a lesion in a mammogram, and the figure of merit used is the lesion detectability, expressed as a task-based signal-to-noise ratio (SNR), for a channelized Hotelling observer (CHO). As in the previous work, the statistical model accounts for the random structure in the breast, the statistical properties of the scintillation screen, the random coupling of light to the CCD, the detailed structure of the shift-variant lens point spread function (PSF), and Poisson noise of the X-ray flux. The lenses considered range from F/0.9 to F/1.2. All yield nominally the same spot size at a given field. Among the F/0.9 lenses, some of them were designed by conventional means for high resolution and some for high contrast, and the shapes of the PSF differ considerably. The results show that excessively large lens numerical apertures do not improve the task-based SNR but dramatically increase the optics fabrication cost. Contrary to common wisdom, high-contrast designs have higher task-based SNRs than high-resolution designs when the signal is small. Additionally, we constructed a merit function to successfully tune the lenses to perform equally well anywhere in the FOV.

  19. 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.

  20. 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...

  1. Object handling tasks based on active tactile and slippage sensations in a multi-fingered humanoid robot arm

    Microsoft Academic Search

    Hanafiah B. Yussof; Jiro Wada; Masahiro Ohka

    2009-01-01

    This paper presents a new algorithm for object handling tasks based on active tactile and slippage sensations using a humanoid robot multifingered arm for an object that exists at an arbitrary position. The idea is to enhance real-time object handling tasks based on tactile sensing in humanoid robotics, where grasp, move and release motions are involved. We developed a novel

  2. Using sensor fusion and contextual information to perform event detection during a phase-based manipulation task

    Microsoft Academic Search

    Marc R. Tremblay; Mark R. Cutkosky

    1995-01-01

    We present an approach to event detection during a dexterous manipulation task. The approach utilizes a combination of tactile sensors as well as contextual information. The manipulation task is decomposed into distinct phases, each of which is associated with a limited number of feasible events such as making or breaking contact, slipping, etc. A set of context-based and sensor-based features

  3. 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 ?, and interferon ?), 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

  4. U.S. Department of Justice: Task Force for Faith-based & Community Initiatives

    NSDL National Science Digital Library

    On January 29, 2001, President George W. Bush issued two executive orders related to faith-based and community organizations. The first established a base of operations within the White House for such initiatives, and the second established centers within various cabinet- level departments, including the Department of Justice (DOJ). As the latter's website notes, "The Task Force's purpose is to promote good works by neighbors, particularly in the areas of juvenile delinquency, prisoners and their families, victims of crime, domestic violence, and drug addiction/treatment/prevention." Visitors to the site can learn about funding opportunities administered by the DOJ and also read some of its publications, such as "Moving Beyond the Walls: Faith and Justice Partnerships Working for High Risk Youth". Interested parties may also want to look at the Task Force's FAQ section and sign up to receive email updates.

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

    SciTech Connect

    Stephen Schey; Jim Francfort

    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.

  6. Historical limitations of determinant based exposure groupings in the rubber manufacturing industry

    PubMed Central

    Vermeulen, R; Kromhout, H

    2005-01-01

    Aims: To study the validity of using a cross-sectional industry-wide exposure survey to develop exposure groupings for epidemiological purposes that extend beyond the time period in which the exposure data were collected. Methods: Exposure determinants were used to group workers into high, medium, and low exposure groups. The contrast of this grouping and other commonly used grouping schemes based on plant and department within this exposure survey and a previously conducted survey within the same industry (and factories) were estimated and compared. Results: Grouping of inhalable and dermal exposure based on exposure determinants resulted in the highest, but still modest, contrast (? ? 0.3). Classifying subjects based on a combination of plant and department resulted in a slightly lower contrast (? ? 0.2). If the determinant based grouping derived from the 1997 exposure survey was used to classify workers in the 1988 survey the average contrast decreased significantly for both exposures (? ? 0.1). On the contrary, the exposure classification based on plant and department increased in contrast (from ? ? 0.2 to ? ? 0.3) and retained its relative ranking overtime. Conclusions: Although determinant based groupings seem to result in more efficient groupings within a cross-sectional survey, they have to be used with caution as they might result in significant less contrast beyond the studied population or time period. It is concluded that a classification based on plant and department might be more desirable for retrospective studies in the rubber manufacturing industry, as they seem to have more historical relevance and are most likely more accurately recorded historically than information on exposure determinants in a particular industry. PMID:16234406

  7. Capturing dynamic patterns of task-based functional connectivity with EEG.

    PubMed

    Karamzadeh, Nader; Medvedev, Andrei; Azari, Afrouz; Gandjbakhche, Amir; Najafizadeh, Laleh

    2013-02-01

    A new approach to trace the dynamic patterns of task-based functional connectivity, by combining signal segmentation, dynamic time warping (DTW), and Quality Threshold (QT) clustering techniques, is presented. Electroencephalography (EEG) signals of 5 healthy subjects were recorded as they performed an auditory oddball and a visual modified oddball tasks. To capture the dynamic patterns of functional connectivity during the execution of each task, EEG signals are segmented into durations that correspond to the temporal windows of previously well-studied event-related potentials (ERPs). For each temporal window, DTW is employed to measure the functional similarities among channels. Unlike commonly used temporal similarity measures, such as cross correlation, DTW compares time series by taking into consideration that their alignment properties may vary in time. QT clustering analysis is then used to automatically identify the functionally connected regions in each temporal window. For each task, the proposed approach was able to establish a unique sequence of dynamic pattern (observed in all 5 subjects) for brain functional connectivity. PMID:23142654

  8. Acute exposure to power-frequency magnetic fields has no effect on the acquisition of a spatial learning task by adult male mice

    SciTech Connect

    Sienkiewicz, Z.J.; Haylock, R.G.E.; Saunders, R.D. [National Radiological Protection Board, Chilton (United Kingdom)] [National Radiological Protection Board, Chilton (United Kingdom)

    1996-12-01

    A series of four experiments was performed to determine whether acute exposure to a range of 50 Hz magnetic fields had any effect on a learning task in adult male CD1 mice. A radial-arm maze placed within the bore of an electromagnetic was used to assess spatial discrimination learning for food reward. Subjects were reduced to 85% of their free-feeding weight and were placed in the maze for up to 15 minutes each day for 10 days. Performance of the task was measured by using maximum likelihood techniques to calculate the probability that an animal would not reenter any given arm of the maze. Experimental subjects were exposed to a vertical, 50 Hz sinusoidal magnetic field at 5 {micro}T, 50 {micro}T, 0.5 mT, or 5.0 mT (rms). Control subjects were exposed only to a background time-varying field of less than 50 nT and the ambient static field of about 40 {micro}T. The variation in the applied magnetic field was less than 5% except at the ends of the arms, where is approached 10%. It was found that all eight groups of subjects (n = 10 in all cases) showed similar increases in performance with testing, and the acquisition curve for each group of experimental subjects was not significantly different from that of their control group (P > 0.05 in all cases). It was concluded that exposure had no effect on learning at any flux density. This result is contrary to the findings of a number of preliminary studies, although other studies have reported that magnetic fields do not affect spatial learning in adult male rodents. It is possible that differences between experimental conditions might explain some of this apparent discrepancy.

  9. Task Partitioning Wireless Base-station Receiver Algorithms on Multiple DSPs and FPGAs

    Microsoft Academic Search

    Sridhar Rajagopal; Bryan Jones; Joseph R. Cavallaro

    2000-01-01

    This paper presents a multiprocessor solution to meet real-time requirements of implementing advanced algorithms for multiuser channel esti- mation and detection for third and fourth genera- tion wireless base-station receivers. We identify the key bottlenecks in the algorithms and task- partition the algorithms on multiple processors. We get speedups, ranging from 1.19X to 5.92X for a dual-DSP implementationdue to both

  10. Development and evaluation of a microprocessor-based ergonomic dosimeter for evaluating carpentry tasks

    Microsoft Academic Search

    A. Bhattacharya; J. Warren; J. Teuschler; M. Dimov; M. Medvedovic; G. Lemasters

    1999-01-01

    This portable and self-contained lightweight microprocessor based Ergonomic Dosimeter is designed to collect continuously postural angles of the torso and the upper arm in the sagittal plane and the number of kneeling activities. Up to 4h of task performance data can be stored in a non-volatile memory of the dosimeter, which can then be downloaded to a lap-top computer. The

  11. A Library-Based Approach to Task Parallelism in a Data-Parallel Language

    Microsoft Academic Search

    Ian T. Foster; David R. Kohr Jr.; Rakesh Krishnaiyer; Alok N. Choudhary

    1997-01-01

    Pure data-parallel languages such as High Performance For- tran version 1 (HPF) do not allow efficient expression of mixed task\\/data-parallel computations or the coupling of separately compiled data-parallel modules. In this paper, we show how these common parallel program structures can be represented, with only minor extensions to the HPF model, by using a coordi- nation library based on the

  12. 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. ...

  13. 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 ESA’s 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 AIUB’s 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.

  14. Age differences in strategic behavior during a computation-based skill acquisition task

    PubMed Central

    Touron, Dayna R.; Hertzog, Christopher

    2009-01-01

    The present experiment evaluated mechanistic and metacognitive accounts of age differences in strategy transitions during skill acquisition. Old and young participants were trained on a task involving a shift from performing a novel arithmetic algorithm to responding via associative recognition of equation-solution pairings. The strategy shift was manipulated by task instructions that either (a) equally focused on speed and accuracy, (b) encouraged retrieval use as a method toward fast responding, or (c) offered monetary incentives for fast retrieval-based performance. Monetary incentives produced a more rapid shift to retrieval relative to standard instructions; older adults showed a greater incentives effect on retrieval use than younger adults. Monetary incentives encouraged retrieval use and RT improvements despite accuracy costs (a speed-accuracy tradeoff). The pattern of results suggested a role of metacognitive and volitional factors in retrieval shift, indicating that an associative learning deficit cannot fully account for older adults’ delayed strategy shift. PMID:19739913

  15. A library of problem-solving components based on the integration of the search paradigm with task and method ontologies

    Microsoft Academic Search

    Enrico Motta; Zdenek Zdráhal

    1998-01-01

    In this paper we investigate the reuse of tasks and problem solving methods and we propose a model of how to organize a library of reusable components for knowledge based systems. In our approach we first describe a class of problems by means of a task ontology. Then we instantiate a generic model of problem solving as search in terms

  16. 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...

  17. 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...

  18. Biology Based Lung Cancer Model for Chronic Low Radon Exposures

    NASA Astrophysics Data System (ADS)

    Truţ?-Popa, Lucia-Adina; Hofmann, Werner; Fakir, Hatim; Cosma, Constantin

    2008-08-01

    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.

  19. Discrimination Task Reveals Differences in Neural Bases of Tinnitus and Hearing Impairment

    PubMed Central

    Husain, Fatima T.; Pajor, Nathan M.; Smith, Jason F.; Kim, H. Jeff; Rudy, Susan; Zalewski, Christopher; Brewer, Carmen; Horwitz, Barry

    2011-01-01

    We investigated auditory perception and cognitive processing in individuals with chronic tinnitus or hearing loss using functional magnetic resonance imaging (fMRI). Our participants belonged to one of three groups: bilateral hearing loss and tinnitus (TIN), bilateral hearing loss without tinnitus (HL), and normal hearing without tinnitus (NH). We employed pure tones and frequency-modulated sweeps as stimuli in two tasks: passive listening and active discrimination. All subjects had normal hearing through 2 kHz and all stimuli were low-pass filtered at 2 kHz so that all participants could hear them equally well. Performance was similar among all three groups for the discrimination task. In all participants, a distributed set of brain regions including the primary and non-primary auditory cortices showed greater response for both tasks compared to rest. Comparing the groups directly, we found decreased activation in the parietal and frontal lobes in the participants with tinnitus compared to the HL group and decreased response in the frontal lobes relative to the NH group. Additionally, the HL subjects exhibited increased response in the anterior cingulate relative to the NH group. Our results suggest that a differential engagement of a putative auditory attention and short-term memory network, comprising regions in the frontal, parietal and temporal cortices and the anterior cingulate, may represent a key difference in the neural bases of chronic tinnitus accompanied by hearing loss relative to hearing loss alone. PMID:22066003

  20. 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. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2 M9 (Canada); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Carestream Health, Rochester, New York 14615 (United States); Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21287 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2 M9 (Canada) and Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21287 (United States)

    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.

  1. A Population-Based Job Exposure Matrix for Power-Frequency Magnetic Fields

    Microsoft Academic Search

    Joseph D. Bowman; Jennifer A. Touchstone; Michael G. Yost

    2007-01-01

    A population-based job exposure matrix (JEM) was developed to assess personal exposures to power-frequency magnetic fields (MF) for epidemiologic studies. The JEM compiled 2317 MF measurements taken on or near workers by 10 studies in the United States, Sweden, New Zealand, Finland, and Italy. A database was assembled from the original data for six studies plus summary statistics grouped by

  2. Brain bases of error-related ERPs as influenced by age and task

    Microsoft Academic Search

    Karen J. Mathewson; Jane Dywan; Sidney J. Segalowitz

    2005-01-01

    Age effects in the error negativity (Ne) and error positivity (Pe) were examined in a standard letter flanker task and an age-sensitive source memory exclusion task. Older adults made more errors and produced Ne and Pe components of lower amplitude in both tasks. The Ne was insensitive to task and error rate. The Pe, however, was reduced in the source

  3. Design and implementation of control system software based on VxWorks multi-tasks

    Microsoft Academic Search

    Zhen Zhang; Yan Li

    2010-01-01

    This article first introduces an embedded real-time operating system VxWorks and its multi-tasks mechanism. Combining the requirements of the control system which needs to complete the engineering tasks and multi-task, real-time, it gives serial port driver and design of application layer. It proposes a multiple-task model and a method of task-scheduling. It also offers the detailed artifice of measurement under

  4. Application of ensemble classifier in EEG-based motor imagery tasks

    NASA Astrophysics Data System (ADS)

    Liu, Bianhong; Hao, Hongwei

    2007-12-01

    Electroencephalogram (EEG) recorded during motor imagery tasks can be used to move a cursor to a target on a computer screen. Such an EEG-based brain-computer interface (BCI) can provide a new communication channel for the subjects with neuromuscular disorders. To achieve higher speed and more accuracy to enhance the practical applications of BCI in computer aid medical systems, the ensemble classifier is used for the single classification. The ERDs at the electrodes C3 and C4 are calculated and then stacked together into the feature vector for the ensemble classifier. The ensemble classifier is based on Linear Discriminant Analysis (LDA) and Nearest Neighbor (NN). Furthermore, it considers the feedback. This method is successfully used in the 2003 international data analysis competition on BCI-tasks (data set III). The results show that the ensemble classifier succeed with a recognition as 90%, on average, which is 5% and 3% higher than that of using the LDA and NN separately. Moreover, the ensemble classifier outperforms LDA and NN in the whole time course. With adequate recognition, ease of use and clearly understood, the ensemble classifier can meet the need of time-requires for single classification.

  5. 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.

  6. KERNEL-BASED MULTI-TASK JOINT SPARSE CLASSIFICATION FOR ALZHEIMER'S DISEASE.

    PubMed

    Wang, Yaping; Liu, Manhua; Guo, Lei; Shen, Dinggang

    2013-12-31

    Multi-modality imaging provides complementary information for diagnosis of neurodegenerative disorders such as Alzheimer's disease (AD) and its prodrome, mild cognitive impairment (MCI). In this paper, we propose a kernel-based multi-task sparse representation model to combine the strengths of MRI and PET imaging features for improved classification of AD. Sparse representation based classification seeks to represent the testing data with a sparse linear combination of training data. Here, our approach allows information from different imaging modalities to be used for enforcing class level joint sparsity via multi-task learning. Thus the common most representative classes in the training samples for all modalities are jointly selected to reconstruct the testing sample. We further improve the discriminatory power by extending the framework to the reproducing kernel Hilbert space (RKHS) so that nonlinearity in the features can be captured for better classification. Experiments on Alzheimer's Disease Neuroimaging Initiative database shows that our proposed method can achieve 93.3% and 78.9% accuracy for classification of AD and MCI from healthy controls, respectively, demonstrating promising performance in AD study. PMID:24443696

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

    PubMed

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

    2014-05-01

    ABSTRACT. 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. PMID:24862561

  8. 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

  9. 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

  10. 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

  11. 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

  12. Metaheuristic Based Scheduling Meta-Tasks in Distributed Heterogeneous Computing Systems

    PubMed Central

    Izakian, Hesam; Abraham, Ajith; Snášel, Václav

    2009-01-01

    Scheduling is a key problem in distributed heterogeneous computing systems in order to benefit from the large computing capacity of such systems and is an NP-complete problem. In this paper, we present a metaheuristic technique, namely the Particle Swarm Optimization (PSO) algorithm, for this problem. PSO is a population-based search algorithm based on the simulation of the social behavior of bird flocking and fish schooling. Particles fly in problem search space to find optimal or near-optimal solutions. The scheduler aims at minimizing makespan, which is the time when finishes the latest task. Experimental studies show that the proposed method is more efficient and surpasses those of reported PSO and GA approaches for this problem. PMID:22346701

  13. Development and evaluation of a microprocessor-based ergonomic dosimeter for evaluating carpentry tasks.

    PubMed

    Bhattacharya, A; Warren, J; Teuschler, J; Dimov, M; Medvedovic, M; Lemasters, G

    1999-12-01

    This portable and self-contained lightweight microprocessor based Ergonomic Dosimeter is designed to collect continuously postural angles of the torso and the upper arm in the sagittal plane and the number of kneeling activities. Up to 4 h of task performance data can be stored in a non-volatile memory of the dosimeter, which can then be downloaded to a lap-top computer. The portable dosimeter was tested for test-retest reliability, compared with posture data obtained with a computer-based video analysis system and evaluated at a carpenter's apprentices school and at a construction site. The dosimeter was shown to be suitable for collecting posture and kneeling data for a prolonged period at construction sites. PMID:10693834

  14. Metaheuristic based scheduling meta-tasks in distributed heterogeneous computing systems.

    PubMed

    Izakian, Hesam; Abraham, Ajith; Snášel, Václav

    2009-01-01

    Scheduling is a key problem in distributed heterogeneous computing systems in order to benefit from the large computing capacity of such systems and is an NP-complete problem. In this paper, we present a metaheuristic technique, namely the Particle Swarm Optimization (PSO) algorithm, for this problem. PSO is a population-based search algorithm based on the simulation of the social behavior of bird flocking and fish schooling. Particles fly in problem search space to find optimal or near-optimal solutions. The scheduler aims at minimizing makespan, which is the time when finishes the latest task. Experimental studies show that the proposed method is more efficient and surpasses those of reported PSO and GA approaches for this problem. PMID:22346701

  15. Abstract--Evidence-based medicine is a new direction in modern healthcare. Its task is to prevent, diagnose and medicate

    E-print Network

    for strategic decision making, which has a great relevance for the practice and acceptance of evidence-basedAbstract-- Evidence-based medicine is a new direction in modern healthcare. Its task is to prevent to the healthcare practitioners at right time and in the right manner. External evidence-based knowledge can

  16. Clustering-Based Simultaneous Task and Voltage Scheduling for NoC Systems 

    E-print Network

    Yang, Yu

    2011-08-08

    not only assigns voltage levels and starting time to each task (or Processing Element) but also naturally finds voltage-frequency clusters. Compared to a recent previous work, which performs task scheduling and voltage assignment sequentially, our method...

  17. Occupational exposure to water based paint and symptoms from the skin and eyes

    Microsoft Academic Search

    G Wieslander; D Norbäck; C Edling

    1994-01-01

    Water based paints contain organic solvents and many additives, such as biocides, surfactants, pigments, binders, amines, and monomers. The chemical complexity may introduce new potential health hazards to house painters, in particular irritative and allergic disorders. This study was performed to compare how house painters experience work with water based paints or solvent based paints, and to evaluate whether exposure

  18. AMER. ZOOL., 28:125-135 (1988) Physiological Responses to Air Exposure: Acid-Base

    E-print Network

    Burnett, Louis E.

    1988-01-01

    AMER. ZOOL., 28:125-135 (1988) Physiological Responses to Air Exposure: Acid-Base Balance with the aerial environment. Among the animals using the first behavior, body fluid acid-base balance is partially. Both strategies are interesting from the perspective of acid- base balance. On the one hand, anaerobic

  19. Task performance in astronomical adaptive optics

    NASA Astrophysics Data System (ADS)

    Barrett, Harrison H.; Myers, Kyle J.; Devaney, Nicholas; Dainty, J. C.; Caucci, Luca

    2006-06-01

    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.

  20. Calibrating a population-based job-exposure matrix using inspection measurements to estimate historical occupational exposure to lead for a population-based cohort in Shanghai, China

    PubMed Central

    Koh, Dong-Hee; Bhatti, Parveen; Coble, Joseph B.; Stewart, Patricia A; Lu, Wei; Shu, Xiao-Ou; Ji, Bu-Tian; Xue, Shouzheng; Locke, Sarah J.; Portengen, Lutzen; Yang, Gong; Chow, Wong-Ho; Gao, Yu-Tang; Rothman, Nathaniel; Vermeulen, Roel; Friesen, Melissa C.

    2012-01-01

    The epidemiologic evidence for the carcinogenicity of lead is inconsistent and requires improved exposure assessment to estimate risk. We evaluated historical occupational lead exposure for a population-based cohort of women (n=74,942) by calibrating a job-exposure matrix (JEM) with lead fume (n=20,084) and lead dust (n=5,383) measurements collected over four decades in Shanghai, China. Using mixed-effect models, we calibrated intensity JEM ratings to the measurements using fixed-effects terms for year and JEM rating. We developed job/industry-specific estimates from the random-effects terms for job and industry. The model estimates were applied to subjects’ jobs when the JEM probability rating was high for either job or industry; remaining jobs were considered unexposed. The models predicted that exposure increased monotonically with JEM intensity rating and decreased 20–50-fold over time. The cumulative calibrated JEM estimates and job/industry-specific estimates were highly correlated (Pearson correlation=0.79–0.84). Overall, 5% of the person-years and 8% of the women were exposed to lead fume; 2% of the person-years and 4% of the women were exposed to lead dust. The most common lead-exposed jobs were manufacturing electronic equipment. These historical lead estimates should enhance our ability to detect associations between lead exposure and cancer risk in future epidemiologic analyses. PMID:22910004

  1. Calibrating a population-based job-exposure matrix using inspection measurements to estimate historical occupational exposure to lead for a population-based cohort in Shanghai, China.

    PubMed

    Koh, Dong-Hee; Bhatti, Parveen; Coble, Joseph B; Stewart, Patricia A; Lu, Wei; Shu, Xiao-Ou; Ji, Bu-Tian; Xue, Shouzheng; Locke, Sarah J; Portengen, Lutzen; Yang, Gong; Chow, Wong-Ho; Gao, Yu-Tang; Rothman, Nathaniel; Vermeulen, Roel; Friesen, Melissa C

    2014-01-01

    The epidemiologic evidence for the carcinogenicity of lead is inconsistent and requires improved exposure assessment to estimate risk. We evaluated historical occupational lead exposure for a population-based cohort of women (n=74,942) by calibrating a job-exposure matrix (JEM) with lead fume (n=20,084) and lead dust (n=5383) measurements collected over four decades in Shanghai, China. Using mixed-effect models, we calibrated intensity JEM ratings to the measurements using fixed-effects terms for year and JEM rating. We developed job/industry-specific estimates from the random-effects terms for job and industry. The model estimates were applied to subjects' jobs when the JEM probability rating was high for either job or industry; remaining jobs were considered unexposed. The models predicted that exposure increased monotonically with JEM intensity rating and decreased 20-50-fold over time. The cumulative calibrated JEM estimates and job/industry-specific estimates were highly correlated (Pearson correlation=0.79-0.84). Overall, 5% of the person-years and 8% of the women were exposed to lead fume; 2% of the person-years and 4% of the women were exposed to lead dust. The most common lead-exposed jobs were manufacturing electronic equipment. These historical lead estimates should enhance our ability to detect associations between lead exposure and cancer risk in the future epidemiologic analyses. PMID:22910004

  2. Effect of donepezil on reversal learning in a touch screen-based operant task.

    PubMed

    Chen, Woei-Shin; Wong, Fong-Kuan; Chapman, Paul F; Pemberton, Darrel J

    2009-10-01

    Impairments in reversal learning, which are commonly observed in patients with psychiatric disorders, remain difficult to treat. There is still a debate over the beneficial effects of cholinergic enhancers on improving behavioural flexibility. The objective of this study was to investigate the effect of an acetylcholinesterase inhibitor, donepezil, on the performance of a rodent Probabilistic Reversal Learning task. Lister-Hooded rats were trained to retrieve food rewards by discriminating two computer-generated stimuli in an automated touch screen-based operant task. When a steady performance was achieved, the stimulus-reward rule was reversed. Each rat was given a 30-min training session daily for 24 days and donepezil was administered 30?min before each training session. Systemic treatment with donepezil had no effect on trial accuracy of the two-stimulus discrimination training. However, the donepezil group showed enhanced performance in the reversal learning. Our result showed that treatment with donepezil significantly enhanced Probabilistic Reversal Learning performance in healthy animals. On the basis of this finding, the inhibition of the central acetylcholinesterase would seem to be a potential therapeutic approach to treat behavioural inflexibility. PMID:19654507

  3. Classifying real and imaginary finger press tasks on a P300-based brain-computer interface.

    PubMed

    Zhang, Jicai; Chen, Weidong; Gu, Yanlei; Wu, Bian; Qi, Yu; Zheng, Xiaoxiang

    2011-01-01

    Brain computer interfaces based on P300 and sensory-motor rhythms are widely studied and recent advances show some interest in the combination of the two. In this paper, typical P300 paradigm is modified by adding animation guide of the finger press as a stimulus and by using different response strategies (silent counting and actual/imaginary left or right index finger press following the animation). Both P300 potentials and sensory-motor rhythms are directly exploited and discussed. Classification results showed that even under very demanding conditions, which was, 200 ms inter-stimulus interval of the P300 stimuli and actual/imaginary finger press once per 1.6s, the paradigm can evoke both P300 potentials and sensory-motor rhythms simultaneously. Actual finger press increased single trial P300 selection accuracy of different subjects by 5-29.5% compared with silent counting; imaginary finger press did not increase the P300 selection accuracy apparently for most subjects except the two who were very poor at counting task. This showed by using different interface design and adopting certain mental response strategies, the 'BCI illiteracy' may be cured. Also imaginary task had good performance of left versus right classification (with the best subject reached 81.1% of accuracy), which is an additional information that can be used to improve system performance. PMID:22255792

  4. The impact of planning time on children’s task-based interactions

    Microsoft Academic Search

    Jenefer Philp; Rhonda Oliver; Alison Mackey

    2006-01-01

    Recently, tasks have been advocated for their role in promoting participation in L2 interaction and the provision and use of feedback by language learners (Bygate, M., Skehan, P., Swain, M. (Eds.), 2001. Researching Pedagogical Tasks: Second Language Learning, Teaching and Testing. Pearson Education, Harlow). The relationship between various aspects of pre-task planning time and the quality of learners’ output in

  5. Real-Time Management of Hardware and Software Tasks for FPGA-based Embedded Systems

    Microsoft Academic Search

    Rodolfo Pellizzoni; Marco Caccamo

    2007-01-01

    Operating systems for reconfigurable devices enable the development of embedded systems where software tasks, running on a CPU, can coexist with hardware tasks running on a reconfigurable hardware device (FPGA). In this work, we consider real-time systems subject to dynamic workloads and whose tasks can be computationally intensive. We introduce a novel resource allocation scheme and an online admission control

  6. Method for carrier aircraft task flow safety analysis based on TPN

    Microsoft Academic Search

    Zhaoguang Peng; Tingdi Zhao; Jin Tian

    2011-01-01

    With tight timing, sequencing and compact, the time error of any task flow activities of carrier aircrafts may result flow fracturing, leading to unsafe task. Currently, the research in the carrier aircraft safety is mainly focused on the quality of its flight dynamics modeling and simulation, while for carrier aircraft task flow analysis, its improvement, and safety induced by the

  7. 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…

  8. Algorithms for Determining the Demand-Based Load of a Sporadic Task System

    Microsoft Academic Search

    Nathan Fisher; Theodore P. Baker; Sanjoy K. Baruah

    2006-01-01

    The load parameter of a sporadic task system is de- flned to be the largest possible cumulative execution re- quirement that can be generated by jobs of the task sys- tem over any time interval, normalized by the length of the interval. This parameter is known to play a very important role in the uniprocessor feasibility analysis of sporadic task

  9. 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

  10. Test of a vision-based autonomous space station robotic task

    NASA Astrophysics Data System (ADS)

    Castellano, Anthony R.; Hwang, Vincent S. S.; Stoney, William E.

    1991-02-01

    An area of increasing interest in Al Robotics and Computer Vision is integrating techniques from these fields to the problem of controlling autonomous systems. Space-based systems such as NASA''s robotic assembly of Orbital Replacement Units (ORU''s) provide a complex realistic domain for this integration research. In this paper we report on current MITRE research in the use of situated control for autonomous robotic assembly of ORUs. A wrist-mounted camera is used to acquire the pose of ORU''s. An on-line control module uses the pose data to refine the on-going robot actions so that the planned task can be executed both safely and robustly. Experimental results on a Cincinnati Milacron T3 Industrial robot at Goddard Space Right Center (GSFC) Intelligent Robotic Laboratory will be included.

  11. 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 ?2,1-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

  12. 1H NMR-based metabonomic investigation of tributyl phosphate exposure in rats

    Microsoft Academic Search

    Muniasamy Neerathilingam; David E. Volk; Swapna Sarkar; Todd M. Alam; M. Kathleen Alam; G. A. Shakeel Ansari; Bruce A. Luxon

    2010-01-01

    Tributyl phosphate (TBP) is a toxic organophosphorous compound widely used in many industrial applications, including significant usage in nuclear processing. The industrial application of this chemical is responsible for occupational exposure and environmental pollution. In this study, 1H NMR-based metabonomics has been applied to investigate the metabolic response to TBP exposure. Male Sprague-Dawley rats were given a TBP-dose of 15mg\\/kg

  13. 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.

  14. Analysis of radiation exposure for Task Force Big Bang, Shot Galileo. Exercise Desert Rock VII-VIII Operation Plumbbob. Final report, 27 February 1978-19 July 1979

    SciTech Connect

    Goetz, J.L.; Kaul, D.; Klemm, J.; McGahan, J.T.; McRaney, W.K.

    1980-04-09

    The radiation doses to Task Force BIG BANG troops who participated in Shot GALILEO are determined and compared with film badge data gathered during Exercise Desert Rock VII-VIII. Fallout contours and decay rates, are established and used to calculate total external beta and gamma doses, based on estimated stay time for various troop activities. Uncertainties are calculated for each parameter. Radiation dose from internal emitters, due to inhalation of resuspended contaminated particles, is calculated. Total external gamma dose is estimated to be 1070-1780 mrem as compared with a mean film badge reading of 1900 mrem. 50-year bone dose, due to internal emitters, is estimated to be 10-25 mrem.

  15. 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…

  16. 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…

  17. Non-linguistic learning and aphasia: Evidence from a paired associate and feedback-based task

    PubMed Central

    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 (Helm-Estabrooks, 2002 for review). Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success (Freedman & Martin, 2001; Hula & McNeil, 2008; Ramsberger, 2005). 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

  18. A comparison of exposure methods for SPME-based bioavailability estimates.

    PubMed

    Harwood, Amanda D; Landrum, Peter F; Lydy, Michael J

    2012-02-01

    The ability of polydimethlysiloxane coated solid phase microextraction (SPME) fibers to predict bioavailability has been documented for a number of species and compounds. There are also a variety of established methods for establishing SPME-based bioavailability estimates; however, factors such as time until equilibrium and exposure regimen could affect fiber concentrations and have not yet been thoroughly tested. Exposure time may influence SPME fiber concentrations at equilibrium. Co-exposure of the fibers with different animals or the invertebrate species used could yield different estimates than those acquired using a shaker table system to achieve equilibrium between the sediment and SPME fibers. The current study examined the effects of time and exposure method (shaker table versus co-exposure with test species) on SPME fiber concentrations for two hydrophobic compounds: permethrin and p,p'-dichlorodiphenyldichloroethylene (DDE). An additional experiment with permethrin determined whether animal densities or fiber number influenced fiber concentrations. There were significant differences between the time required for SPME fibers to reach equilibrium when co-exposed with different species or separately, but fiber concentrations at equilibrium among treatments for both compounds were similar. Furthermore, among the 12 variations in species and fiber densities, there were no significant differences among treatments indicating that neither the route of exposure, animal density, nor fiber volume influenced SPME fiber estimates. This demonstrated that SPME fiber concentrations at equilibrium were not affected by exposure conditions, increasing their versatility in environmental assessments. PMID:22055312

  19. 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

  20. 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…

  1. Author's personal copy Auctions and iMesh based task assignment in wireless sensor

    E-print Network

    Stojmenovic, Ivan

    tasks. Habitat or agricultural monitoring, home automation, object or vehicle surveillance, fire and actuators are usually battery operated. In or- der to minimize battery power consumption and maximize

  2. 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.

  3. 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

  4. Gamma-H2AX-Based Dose Estimation for Whole and Partial Body Radiation Exposure

    PubMed Central

    Horn, Simon; Barnard, Stephen; Rothkamm, Kai

    2011-01-01

    Most human exposures to ionising radiation are partial body exposures. However, to date only limited tools are available for rapid and accurate estimation of the dose distribution and the extent of the body spared from the exposure. These parameters are of great importance for emergency triage and clinical management of exposed individuals. Here, measurements of ?-H2AX immunofluorescence by microscopy and flow cytometry were compared as rapid biodosimetric tools for whole and partial body exposures. Ex vivo uniformly X-irradiated blood lymphocytes from one donor were used to generate a universal biexponential calibration function for ?-H2AX foci/intensity yields per unit dose for time points up to 96 hours post exposure. Foci – but not intensity – levels remained significantly above background for 96 hours for doses of 0.5 Gy or more. Foci-based dose estimates for ex vivo X-irradiated blood samples from 13 volunteers were in excellent agreement with the actual dose delivered to the targeted samples. Flow cytometric dose estimates for X-irradiated blood samples from 8 volunteers were in excellent agreement with the actual dose delivered at 1 hour post exposure but less so at 24 hours post exposure. In partial body exposures, simulated by mixing ex vivo irradiated and unirradiated lymphocytes, foci/intensity distributions were significantly over-dispersed compared to uniformly irradiated lymphocytes. For both methods and in all cases the estimated fraction of irradiated lymphocytes and dose to that fraction, calculated using the zero contaminated Poisson test and ?-H2AX calibration function, were in good agreement with the actual mixing ratios and doses delivered to the samples. In conclusion, ?-H2AX analysis of irradiated lymphocytes enables rapid and accurate assessment of whole body doses while dispersion analysis of foci or intensity distributions helps determine partial body doses and the irradiated fraction size in cases of partial body exposures. PMID:21966430

  5. Analogical-mapping-based comparison tasks as a scaffold for argumentation

    NASA Astrophysics Data System (ADS)

    Emig, Brandon R.

    Given the centrality of the argumentation process to science and consequent importance to science education, inviting science students to engage in argumentation and scaffolding that argumentation in order that it lead to learning and not frustration is important. The present research invites small groups of science content learners (54 preservice elementary teachers at a large research university) to use analogical-mapping-based comparison tasks in service of argumentation to determine which of two possible analogues, in this case simple machines, is most closely related to a third. These activities and associated instruction scaffolded student small-groups' argumentation in four ways: (1) supporting new analogical correspondences on the heels of prior correspondences; (2) discerning definitions and descriptions for simple machine elements; (3) identifying and dealing with ambiguity in potential correspondences; and (4) making reflections on prior analogical correspondences in service of their final arguments. Analogical-mapping-based comparison activities scaffolded student small groups both in their argumentation and in content learning about simple machines. Implications, limitations, and directions for future related research are also discussed.

  6. int. j. prod. res., 2001, vol. 39, no. 9, 1955 1968 Heuristic approach for assigning workers to tasks based on individual

    E-print Network

    Nembhard, David A.

    to tasks based on individual learning rates D. A. NEMBHARD{ A heuristic worker± task assignment based, worker assignment based on individual characteristics of learning has International Journal of Production@engr.wisc.edu #12;signi® cant potential to improve productivity in organizations. An individual-based model

  7. The Impact of Planning Time on Children's Task-Based Interactions

    ERIC Educational Resources Information Center

    Philp, Jenefer; Oliver, Rhonda; Mackey, Alison

    2006-01-01

    Recently, tasks have been advocated for their role in promoting participation in L2 interaction and the provision and use of feedback by language learners (Bygate, M., Skehan, P., Swain, M. (Eds.), 2001. "Researching Pedagogical Tasks: Second Language Learning, Teaching and Testing." Pearson Education, Harlow). The relationship between various…

  8. 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.

  9. An Empirical Comparison of Graph-based Dimensionality Reduction Algorithms on Facial Expression Recognition Tasks

    E-print Network

    Buenaposada Biencinto, José Miguel

    recognition is a topic of interest both in industry and academia. Recent approaches to facial expression algorithms on a facial expres- sion recognition task. For this task, experimental re- sults show is the recognition of human facial expres- sions. Recently, much effort is being devoted within the computer vision

  10. Issues in evolving GP based classifiers for a pattern recognition task

    Microsoft Academic Search

    Ankur M. Teredesai; Venu Govindaraju

    2004-01-01

    This paper discusses issues when evolving genetic programming (GP) classifiers for a pattern recognition task such as handwritten digit recognition. Developing elegant solutions for handwritten digit classification is a challenging task. Similarly, design and training of classifiers using genetic programming is a relatively new approach in pattern recognition as compared to other traditional techniques. Several strategies for GP training are

  11. Task-based evaluation of skin detection for communication and perceptual interfaces

    Microsoft Academic Search

    Stephen J. Schmugge; M. Adeel Zaffar; Leonid V. Tsap; Min C. Shin

    2007-01-01

    Skin detection is frequently used as the first step for the tasks of face and gesture recognition in perceptual interfaces for human–computer interaction and communication. Thus, it is important for the researchers using skin detection to choose the optimal method for their specific task. In this paper, we propose a novel method of measuring the performance of skin detection for

  12. A task-based analysis of machinery entanglement injuries among Western Canadian farmers.

    PubMed

    Narasimhan, Gopinath; Crowe, Trever G; Peng, Yingwei; Hagel, Louise; Dosman, James; Pickett, William

    2011-10-01

    Machinery entanglements are a leading cause of hospitalized injury on Canadian farms. This study evaluates the role farm tasks play in the occurrence of machinery entanglement events. A retrospective case series of 41 entanglement injuries involving 35 farm-machinery types was assembled. Only a few limited tasks were implicated in the majority of entanglements. These tasks were as follows: (1) field adjustments of machinery; (2) product handling and conveyance; and (3) driveline attachments and servicing. Hazards inherent and common to these tasks affected the behavior of farmers, leading to entanglements. This study establishes a need to identify hazards and assess risks associated with different tasks involving the use of farm machinery under actual field situations. Systemic changes are required to improve existing machinery safety practices through engineering, work methods, and work practice modifications. In addition to design solutions, occupational health and safety strategies should consider activities associated with hazardous situations to inform the content of injury prevention efforts. PMID:21958400

  13. From manganism to manganese-induced parkinsonism: a conceptual model based on the evolution of exposure.

    PubMed

    Lucchini, Roberto G; Martin, Christopher J; Doney, Brent C

    2009-01-01

    Manganism is a distinct medical condition from Parkinson's disease. Manganese exposure scenarios in the last century generally have changed from the acute, high-level exposure conditions responsible for the occurrence of manganism to chronic exposure to much lower levels. Such chronic exposures may progressively extend the site of manganese deposition and toxicity from the globus pallidus to the entire area of the basal ganglia, including the substantia nigra pars compacta involved in Parkinson's disease. The mechanisms of manganese neurotoxicity from chronic exposure to very low levels are not well understood, but promising information is based on the concept of susceptibility that may place individuals exposed to manganese at a higher risk for developing Parkinsonian disturbances. These conditions include mutations of genes which play important pathogenetic roles in both Parkinsonism and in the regulation of manganese transport and metabolism. Liver function is also important in manganese-related neurotoxicity and sub-clinical impairment may increase the risk of Parkinsonism. The purpose and scope of this report are to explore the literature concerning manganese exposure and potential subclinical effects and biological pathways, impairment, and development of diseases such as Parkinsonism and manganism. Inhalation and ingestion of manganese will be the focus of this report. PMID:20012385

  14. Dosimeter based on 8-methoxypsoralen for UVA exposures over extended periods.

    PubMed

    Wainwright, L; Parisi, A V; Downs, N

    2015-07-01

    A miniaturized UVA dosimeter based on 8-methoxypsoralen (8-MOP) has been developed and characterized for the evaluation of UVA (320-400nm) exposures over extended periods longer than one day. Current research indicates that UVA is a contributing factor in non-melanoma skin cancers and the associated financial cost of damage caused by UVA is significant. Dosimetry is a technique that is commonly employed to measure UV exposures to an object or subject. Miniaturized dosimeters using polyphenylene oxide (PPO) have previously been used to measure received erythemal UV (UVery) exposures. A new miniaturized dosimeter using 8-MOP as the photoactive material has been characterized and a technique developed for the calibration of UVA exposures. Using Mylar as a UVB filter the spectral response showed 8-MOP to react only to wavelengths between 320 and 400nm. The measured cosine response has an error of less than 13.8% for angles between 0° and 60°. Seasonal dose response tests conducted, indicate that these UVA dosimeters are able to measure exposures <4.6kJ/m(2). These results have shown that a dosimeter constructed from 8-MOP in conjunction with a Mylar filter can measure UVA exposures over extended periods longer than one day. PMID:25981186

  15. Quantitative assessment of inhalation exposure and deposited dose of aerosol from nanotechnology-based consumer sprays†

    PubMed Central

    Nazarenko, Yevgen; Lioy, Paul J.; Mainelis, Gediminas

    2015-01-01

    This study provides a quantitative assessment of inhalation exposure and deposited aerosol dose in the 14 nm to 20 ?m particle size range based on the aerosol measurements conducted during realistic usage simulation of five nanotechnology-based and five regular spray products matching the nano-products by purpose of application. The products were also examined using transmission electron microscopy. In seven out of ten sprays, the highest inhalation exposure was observed for the coarse (2.5–10 ?m) particles while being minimal or below the detection limit for the remaining three sprays. Nanosized aerosol particles (14–100 nm) were released, which resulted in low but measurable inhalation exposures from all of the investigated consumer sprays. Eight out of ten products produced high total deposited aerosol doses on the order of 101–103 ng kg?1 bw per application, ~85–88% of which were in the head airways, only <10% in the alveolar region and <8% in the tracheobronchial region. One nano and one regular spray produced substantially lower total deposited doses (by 2–4 orders of magnitude less), only ~52–64% of which were in the head while ~29–40% in the alveolar region. The electron microscopy data showed nanosized objects in some products not labeled as nanotechnology-based and conversely did not find nano-objects in some nano-sprays. We found no correlation between nano-object presence and abundance as per the electron microscopy data and the determined inhalation exposures and deposited doses. The findings of this study and the reported quantitative exposure data will be valuable for the manufacturers of nanotechnology-based consumer sprays to minimize inhalation exposure from their products, as well as for the regulators focusing on protecting the public health. PMID:25621175

  16. 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

  17. Toward a domain-independent framework to automate scaffolding of task-based learning in digital games

    Microsoft Academic Search

    James M. Thomas; R. Michael Young

    2009-01-01

    This poster describes a framework that automatically gener- ates learning support sca! olds to guide task-based learning. The aim is to combine the exploratory learning principles prominent in digital games with the rich user modeling and adaptation of intelligent tutoring systems.

  18. Toward a Domain-Independent Framework to Automate Scaffolding of Task-Based Learning in Digital Games

    E-print Network

    Young, R. Michael

    the exploratory learning principles prominent in digital games with the rich user modeling and adaptation of intelligent tutoring systems. Keywords Task-Based Learning, Interactive Narrative, Digital Games, Scaffolding to combine the exploratory learning principles prominent in digital games with the rich user modeling

  19. 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…

  20. 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…

  1. Active Tasks to Change the Use of Class Time within an Outcomes Based Approach to Curriculum Design

    ERIC Educational Resources Information Center

    Salter, Diane; Pang, Marco Y. C.; Sharma, Piyush

    2009-01-01

    This paper describes how new roles for instructors and learners can be integrated into course design and delivery by rethinking course design as part of a process-based staff development program. The goal of incorporating online learning tasks was to engage students with course resources prior to class time through active learning. The staff…

  2. 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…

  3. 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)…

  4. The Application of Peer to Peer SAP-based Q-Learning in Task Assignment to Multiple Robots

    Microsoft Academic Search

    Ding Lijie; Tang Hao; Zhou Lei

    2007-01-01

    This paper proposes a method of solving the task assignment of high-speed handling system to multiple robots. In order to reduce the state space and improve the efficiency of learning, an improved Q-learning algorithm based on peer to peer SAP is designed. In the proposed algorithm, all the Q value of the peer to peer SAP are updated after take

  5. Cost, Precision, and Task Structure in Aggression-based Arbitration for Minimalist Robot Cooperation 

    E-print Network

    Mitra, Tanushree

    2012-10-19

    the relative time to complete 100 navigation tasks in a row. : : 45 xiii FIGURE Page 26 Collective vs. individual performance for girdle length = 30m. The horizontal-axis shows RA’s task length and vertical-axis that of RB. Color bars show the relative.... The arrows show the direction of motion of the robots RA and RB. The ags mark the start and end points for completing one traversal tasks by each robot. The common traversal region of the robots is a narrow corridor, which we term as the \\girdle...

  6. Occupational exposure to asbestos and lung cancer in men: evidence from a population-based case-control study in eight Canadian provinces

    PubMed Central

    2012-01-01

    Background Asbestos is classified as a human carcinogen, and studies have consistently demonstrated that workplace exposure to it increases the risk of developing lung cancer. Few studies have evaluated risks in population-based settings where there is a greater variety in the types of occupations, and exposures. Methods This was a population based case–control study with 1,681 incident cases of lung cancer, and 2,053 controls recruited from 8 Canadian provinces between 1994 and 1997. Self-reported questionnaires were used to elicit a lifetime occupational history, including general tasks, and information for other risk factors. Occupational hygienists, who were blinded to case–control status, assigned asbestos exposures to each job on the basis of (i) concentration (low, medium, high), (ii) frequency (<5%, 5-30%, and >30% of the time in a normal work week), and (iii) reliability (possible, probable, definite). Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI). Results Those occupationally exposed to (i) low, and (ii) medium or high concentrations of asbestos had ORs for lung cancer of 1.17 (95% CI=0.92 – 1.50) and 2.16 (95% CI=1.21-3.88), respectively, relative to those who were unexposed. Medium or high exposure to asbestos roughly doubled the risk for lung cancer across all three smoking pack-year categories. The joint relationship between smoking and asbestos was consistent with a multiplicative risk model. Conclusions Our findings provide further evidence that exposure to asbestos has contributed to an increased risk of lung cancer in Canadian workplaces, and suggests that nearly 3% of lung cancers among Canadian men are caused by occupational exposure to asbestos. PMID:23234401

  7. Estimates of exposure rates and fallout arrival times near the Nevada Test Site

    Microsoft Academic Search

    Carol B. Thompson

    1990-01-01

    One of the tasks of the Off-Site Radiation Exposure Review Project (ORERP) was to estimate doses to individuals resulting from exposure to fallout from nuclear testing at the Nevada Test Site (NTS). Dose estimates are based on estimates of the exposure rate 12 h post-detonation (H + 12) and the time of fallout arrival from events producing discernible fallout at

  8. Near field in the vicinity of wireless base-station antennas: an exposure compliance approach

    Microsoft Academic Search

    Sebastián Blanch; Jordi Romeu; Angel Cardama

    2002-01-01

    Great social concern has risen about the potential health hazard of living near a cellular telephony base-station antenna, and certain technical questions have been posed on the appropriate way to measure exposure in its vicinity. In this paper, a standard spherical near-near field transformation is proposed to obtain the electromagnetic field close to the antenna in free space conditions. The

  9. Efficacy of a school-based primary prevention program for coping with exposure to political violence

    Microsoft Academic Search

    Michelle Slone; Anat Shoshani

    2008-01-01

    A paradigm conceptualizing resilience as factors moderating between political violence exposure and psychological distress administered in a 7-year research project yielded a profile of factors promoting Israeli children's coping in conflict conditions. Three factors — social support mobilization, selfefficacy, and meaning attribution — were incorporated into a school-based primary intervention program. In a repeated measures design, the study assessed pre

  10. Developing Physical Exposure Based Back Injury Risk Models Applicable to Manual Handling Jobs in Distribution Centers

    Microsoft Academic Search

    Steven A. Lavender; William S. Marras; Sue A. Ferguson; Riley E. Splittstoesser; Gang Yang

    2012-01-01

    Exposures to biomechanical low back disorder risk factors were quantified in 195 volunteers who worked in 50 different distribution center jobs using our ultrasound-based “Moment Monitor.” Low back injury rates, determined from a retrospective examination of each company's Occupational Safety and Health Administration (OSHA) 300 records over the 3-year period immediately prior to data collection, were used to classify each

  11. Modifying Exposure-Based CBT for Cambodian Refugees with Posttraumatic Stress Disorder

    ERIC Educational Resources Information Center

    Otto, Michael W.; Hinton, Devon E.

    2006-01-01

    Cambodian refugees represent a severely traumatized population living in the United States. In this paper, we describe the modification of a cognitive-behavior therapy program to facilitate delivery of an exposure-based treatment for posttraumatic stress disorder while addressing some of the challenges brought by differences in language and…

  12. An Integrated Web-Based Assessment Tool for Assessing Pesticide Exposure and Risks

    EPA Science Inventory

    Background/Question/Methods We have created an integrated web-based tool designed to estimate exposure doses and ecological risks under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act. This involved combining a number of disparat...

  13. Aggression and Violence Exposure in Adolescence and the Role of School-Based Policy Initiatives

    ERIC Educational Resources Information Center

    Kennedy, Anne

    2011-01-01

    This article reports on an exploratory study into young people's exposure to aggression and violence. It undertakes a collective examination of the domains occupied by young people and in doing so focuses on an area that has for the most part been overlooked by previous researchers in the UK. The analysis is based on the responses of 98 young…

  14. ATTRIBUTION OF PARTICLE EXPOSURE AND RISK TO COMBUSTION SOURCE EMISSIONS BASED ON PERSONAL PAH EXPOSURE AND URINARY METABOLITES

    EPA Science Inventory

    Personal airborne exposures to carcinogenic particulate PAH have been significantly correlated with exposure to respirable fine particle mass (PM 2.5) in several studies. All combustion sources emit PAH, however the relative concentrations of different PAH and other organic tr...

  15. Knowledge-Based Schematics Drafting: Aesthetic Configuration as a Design Task

    E-print Network

    Valdes-Perez, Raul E.

    Depicting an electrical circuit by a schematic is a tedious task that is a good candidate for automation. Programs that draft schematics with the usual algorithmic approach do not fully exploit knowledge of circuit function, ...

  16. Design and Evaluation of Robust Behavior-Based Controllers for Distributed Multi-Robot Collection Tasks

    E-print Network

    Mataric, Maja J.

    here is distributed multi-robot collection, a class of tasks that includes de-mining and toxic waste physical human intervention is di cult e.g., a toxic waste spill or impossible e.g., an extraterrestrial

  17. Job exposure matrix (JEM)-derived estimates of lifetime occupational pesticide exposure and the risk of Parkinson's disease.

    PubMed

    Liew, Zeyan; Wang, Anthony; Bronstein, Jeff; Ritz, Beate

    2014-01-01

    Studies that report an association between Parkinson's disease (PD) and occupational pesticide exposure often use self-reported exposure and none adjust for concomitant ambient pesticide exposure. For a population-based case-control study of PD conducted in California's heavily agricultural region, the authors developed a comprehensive job exposure matrix (JEM) to assess occupational exposure to pesticides. Relying on 357 incident cases and 750 population controls enrolled between 2001 and 2011, the authors estimated more than a 2-fold risk increase for PD among men classified as highly occupationally exposed. The authors also observed an exposure-response pattern and farming tasks with direct and intense pesticide exposures such as spraying and handling of pesticides resulted in greater risks than indirect bystander exposures. Results did not change after adjustment for ambient pesticide exposure. The authors provide further evidence that occupational pesticide exposure increases the risk of PD. PMID:24499252

  18. A Dual-layer CRFs Based Joint Decoding Method for Cascaded Segmentation and Labeling Tasks

    Microsoft Academic Search

    Yanxin Shi; Mengqiu Wang

    2007-01-01

    Many problems in NLP require solving a cas- cade of subtasks. Traditional pipeline approaches yield to error propagation and prohibit joint train- ing\\/decoding between subtasks. Existing solutions to this problem do not guarantee non-violation of hard-constraints imposed by subtasks and thus give rise to inconsistent results, especially in cases where segmentation task precedes labeling task. We present a method that

  19. L-ALLIANCE: Task-oriented multi-robot learning in behavior-based systems

    Microsoft Academic Search

    Lynne E. Parker

    1996-01-01

    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

  20. Musculoskeletal complaints among nurses related to patient handling tasks and psychosocial factors – Based on logbook registrations

    Microsoft Academic Search

    D. H. Precht; P. Suadicani; N. E. Ebbehøj

    2009-01-01

    The aims were to evaluate the inter-method reliability of a registration sheet for patient handling tasks, to study the day-to-day variation of musculoskeletal complaints (MSC) and to examine whether patient handling tasks and psychosocial factors were associated with MSC.Nurses (n=148) fulfilled logbooks for three consecutive working days followed by a day off. Low back pain (LBP), neck\\/shoulder pain (NSP), knee

  1. Task Analysis Based Methodology for the Design of Face to Face Computer Supported Collaborative Learning Activities

    Microsoft Academic Search

    Maria Francisca Capponi; Miguel Nussbaum; María Ester Lagos

    2006-01-01

    \\u000a This paper shows how Task Analysis can be a powerful tool for the design of collaborative applications supported by wirelessly\\u000a interconnected handhelds. We define a methodology for the design of such activities. It basically consists in performing a\\u000a Task Analysis on an Interaction Model to obtain the set of all possible interactions between actors. Then a class of activities\\u000a is

  2. A model for optimizing step size of learning tasks in competency-based multimedia practicals

    Microsoft Academic Search

    Rob J. Nadolski; Paul A. Kirschner; Jeroen J. G. van Merriënboer; Hans G. K. Hummel

    2001-01-01

    Learners are often overwhelmed by the complexity of realistic learning tasks, but reducing this complexity through traditional\\u000a Instructional Design (ID) methods jeopardizes the authenticity of the learning experience. To solve this apparent paradox,\\u000a a two-phase ID model is presented. Phase 1 consists of cognitive task analysis, where a systematic approach to problem solving\\u000a (SAP) is identified in conjunction with skill

  3. 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

  4. 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.

  5. Distinct neurobehavioral dysfunction based on the timing of developmental binge-like alcohol exposure.

    PubMed

    Sadrian, B; Lopez-Guzman, M; Wilson, D A; Saito, M

    2014-11-01

    Gestational exposure to alcohol can result in long-lasting behavioral deficiencies generally described as fetal alcohol spectrum disorder (FASD). FASD-modeled rodent studies of acute ethanol exposure typically select one developmental window to simulate a specific context equivalent of human embryogenesis, and study consequences of ethanol exposure within that particular developmental epoch. Exposure timing is likely a large determinant in the neurobehavioral consequence of early ethanol exposure, as each brain region is variably susceptible to ethanol cytotoxicity and has unique sensitive periods in their development. We made a parallel comparison of the long-term effects of single-day binge ethanol at either embryonic day 8 (E8) or postnatal day 7 (P7) in male and female mice, and here demonstrate the differential long-term impacts on neuroanatomy, behavior and in vivo electrophysiology of two systems with very different developmental trajectories. The significant long-term differences in odor-evoked activity, local circuit inhibition, and spontaneous coherence between brain regions in the olfacto-hippocampal pathway that were found as a result of developmental ethanol exposure, varied based on insult timing. Long-term effects on cell proliferation and interneuron cell density were also found to vary by insult timing as well as by region. Finally, spatial memory performance and object exploration were affected in P7-exposed mice, but not E8-exposed mice. Our physiology and behavioral results are conceptually coherent with the neuroanatomical data attained from these same mice. Our results recognize both variable and shared effects of ethanol exposure timing on long-term circuit function and their supported behavior. PMID:25241068

  6. Biologically based modeling of multimedia, multipathway, multiroute population exposures to arsenic

    PubMed Central

    Georgopoulos, Panos G.; Wang, Sheng-Wei; Yang, Yu-Ching; Xue, Jianping; Zartarian, Valerie G.; Mccurdy, Thomas; Özkaynak, Halûk

    2011-01-01

    This article presents an integrated, biologically based, source-to-dose assessment framework for modeling multimedia/multipathway/multiroute exposures to arsenic. Case studies demonstrating this framework are presented for three US counties (Hunderton County, NJ; Pima County, AZ; and Franklin County, OH), representing substantially different conditions of exposure. The approach taken utilizes the Modeling ENvironment for TOtal Risk studies (MENTOR) in an implementation that incorporates and extends the approach pioneered by Stochastic Human Exposure and Dose Simulation (SHEDS), in conjunction with a number of available databases, including NATA, NHEXAS, CSFII, and CHAD, and extends modeling techniques that have been developed in recent years. Model results indicate that, in most cases, the food intake pathway is the dominant contributor to total exposure and dose to arsenic. Model predictions are evaluated qualitatively by comparing distributions of predicted total arsenic amounts in urine with those derived using biomarker measurements from the NHEXAS — Region V study: the population distributions of urinary total arsenic levels calculated through MENTOR and from the NHEXAS measurements are in general qualitative agreement. Observed differences are due to various factors, such as interindividual variation in arsenic metabolism in humans, that are not fully accounted for in the current model implementation but can be incorporated in the future, in the open framework of MENTOR. The present study demonstrates that integrated source-to-dose modeling for arsenic can not only provide estimates of the relative contributions of multipathway exposure routes to the total exposure estimates, but can also estimate internal target tissue doses for speciated organic and inorganic arsenic, which can eventually be used to improve evaluation of health risks associated with exposures to arsenic from multiple sources, routes, and pathways. PMID:18073786

  7. Developing Respondent Based Multi-Media Measures of Exposure to Sexual Content

    PubMed Central

    Bleakley, Amy; Fishbein, Martin; Hennessy, Michal; Jordan, Amy; Chernin, Ariel; Stevens, Robin

    2010-01-01

    Despite the interest in the effects of the media on sexual behavior, there is no single method for assessing exposure to a particular type of media content (e.g., sex). This paper discusses the development of six sexual content exposure measures based on adolescents’ own subjective ratings of the sexual content in titles in 4 media (i.e., television, music, magazines, videogames). We assessed the construct and criterion validity of these measures by examining the associations among each of these measures of exposure to sexual content as well as their associations with adolescents’ sexual activity. Data were collected in summer 2005 through a web-based survey using a quota sample of 547 youth aged 14–16 from the Philadelphia area. Adolescents rated how often they were exposed to specific television shows, magazine titles, etc. on 4-point never to often scales. They also rated the sexual content of those titles on 4-point no sexual content to a lot of sexual content scales. Sexual behavior was measured using an ordered index of lifetime pre-coital and coital sexual activity. The strength of association between exposure to sexual content and sexual activity varied by medium and measure. Based on our findings, we recommend the use of a multiple media weighted sum measure. This measure produces findings that are consistent with those of similar studies. PMID:20411048

  8. Sinonasal Cancer and Occupational Exposure in a Population-Based Registry

    PubMed Central

    Mensi, Carolina; Sieno, Claudia; Riboldi, Luciano; Bertazzi, Pier Alberto

    2013-01-01

    We examined occupational exposures among subjects with sinonasal cancer (SNC) recorded in a population-based registry in the Lombardy Region, the most populated and industrialized Italian region. The registry collects complete clinical information and exposure to carcinogens regarding all SNC cases occurring in the population of the region. In the period 2008–2011, we recorded 210 SNC cases (137 men, 73 women). The most frequent occupational exposures were to wood (44 cases, 21.0%) and leather dust (29 cases, 13.8%), especially among men: 39 cases (28.5%) to wood and 23 cases (16.8%) to leather dust. Exposure to other agents was infrequent (<2%). Among 62 subjects with adenocarcinoma, 50% had been exposed to wood dust and 30.7% to leather dust. The proportions were around 10% in subjects with squamous cell carcinoma and about 20% for tumors with another histology. The age-standardized rates (×100,000 person-years) were 0.7 in men and 0.3 in women. Complete collection of cases and their occupational history through a specialized cancer registry is fundamental to accurately monitor SNC occurrence in a population and to uncover exposure to carcinogens in different industrial sectors, even those not considered as posing a high risk of SNC, and also in extraoccupational settings. PMID:24082884

  9. A residue-based toxicokinetic model for pulse-exposure toxicity in aquatic systems

    SciTech Connect

    Hickie, B.E. [Trent Univ., Peterborough, Ontario (Canada). Environmental Resource Studies Program; McCarty, L.S. [L.S. McCarty Scientific Research and Consulting, Oakville, Ontario (Canada); Dixon, D.G. [Univ. of Waterloo, Ontario (Canada). Dept. of Biology

    1995-12-01

    This pulse-exposure model (PULSETOX) is based on the simple one-compartment first-order kinetics (1CFOK) equation. It tracks the accumulation of waterborne organic chemicals by fish and predicts acute toxicity by means of previously established relationships between whole-body residues and lethality. The predictive capabilities of the model were tested with a data set of 27 acute pulse-exposure lethality tests with larval fathead minnows (Pimephales promelas) exposed to pentachlorophenol (PCP). Tests included eight single exposures (2 to 96 h) and 19 multiple exposures, which varied in the number (2 to 15) and duration (2 to 24 h) of pulses, and time interval between pulses (6 to 24 h). Experimental work included determination of 1CFOK kinetics parameters from [{sup 14}C]PCP uptake and clearance, and from time-toxicity curves. Lethality was expected in any exposure regime where the fish reaches or exceeds the critical body residue (CBR) of 0.30 mmol PCP/kg fish (SD, {+-} 0.02; n = 11). Using the CBR endpoint, the model accounted for between 90 and 93% of variability in the observed lethality data, depending on the toxicokinetic parameters employed. Predictive power of the model was optimized by using kinetics parameters derived from the toxicity curve for pulse-toxicity tests as shown by the regression: predicted LC50 = 1.04 {center_dot} (observed LC50) + 0.01 (p < 0.001, r{sup 2} = 0.94, n = 27).

  10. The impact of exposure to shift-based schedules on medical students

    PubMed Central

    Williams, David A.; Kogan, Jennifer R.; Hauer, Karen E.; Yamashita, Traci; Aagaard, Eva M.

    2015-01-01

    Background With new resident duty-hour regulations, resident work schedules have progressively transitioned towards shift-based systems, sometimes resulting in increased team fragmentation. We hypothesized that exposure to shift-based schedules and subsequent team fragmentation would negatively affect medical student experiences during their third-year internal medicine clerkship. Design As part of a larger national study on duty-hour reform, 67 of 150 eligible third-year medical students completed surveys about career choice, teaching and supervision, assessment, patient care, well-being, and attractiveness of a career in internal medicine after completing their internal medicine clerkship. Students who rotated to hospitals with shift-based systems were compared to those who did not. Non-demographic variables used a five-point Likert scale. Chi-squared and Fisher's exact tests were used to assess the relationships between exposure to shift-based schedules and student responses. Questions with univariate p?0.1 were included in multivariable logistic regression models. Results Thirty-six students (54%) were exposed to shift-based schedules. Students exposed to shift-based schedules were less likely to perceive that their attendings were committed to teaching (odds ratio [OR] 0.35, 95% confidence interval [CI]: 0.13–0.90, p=0.01) or perceive that residents had sufficient exposure to assess their performance (OR 0.29, 95% CI: 0.09–0.91, p=0.03). However, those students were more likely to feel their interns were able to observe them at the bedside (OR 1.89, 95% CI: 1.08–3.13, p=0.02) and had sufficient exposure to assess their performance (OR 3.00, 95% CI: 1.01–8.86, p=0.05). Conclusions These findings suggest that shift-based schedules designed in response to duty-hour reform may have important broader implications for the teaching environment. PMID:26095587

  11. 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

  12. 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

  13. Brain biomarkers based assessment of cognitive workload in pilots under various task demands.

    PubMed

    Gentili, Rodolphe J; Rietschel, Jeremy C; Jaquess, Kyle J; Lo, Li-Chuan; Prevost, Michael; Miller, Matt W; Mohler, Jessica M; Oh, Hyuk; Tan, Ying Ying; Hatfield, Bradley D

    2014-01-01

    Cognitive workload is an important element of cognitive-motor performance such as that exhibited during the piloting of an aircraft. Namely, an increase in task demands on the pilot can elevate cognitive information processing and, thus, the risk of human error. As such, there is a need to develop methods that reliably assess mental workload in pilots within operational settings. The present study contributes to this research goal by identifying physiological and brain biomarkers of cognitive workload and attentional reserve during a simulated aircraft piloting task under three progressive levels of challenge. A newly developed experimental method was employed by which electroencephalography (EEG) was acquired via a dry (i.e., gel-free sensors) system using few scalp sites. Self-reported responses to surveys and piloting performance indicators were analyzed. The findings revealed that as the challenge (task demands) increased, the perceived mental load increased, attentional reserve was attenuated, and task performance decreased. Such an increase in task demands was also reflected by changes in heart rate variability (HRV), as well as in the amplitude of the P300 component of event-related potentials to auditory probes, and in the spectral power of specific EEG frequency bands. This work provides a first step towards a long-term goal to develop a composite system of biomarkers for real-time cognitive workload assessment and state assessment of pilots in operational settings. PMID:25571329

  14. Reversal Learning Task in Children with Autism Spectrum Disorder: A Robot-Based Approach.

    PubMed

    Costescu, Cristina A; Vanderborght, Bram; David, Daniel O

    2014-12-01

    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. Potential for exposure to engineered nanoparticles from nanotechnology-based consumer spray products

    PubMed Central

    NAZARENKO, YEVGEN; HAN, TAE WON; LIOY, PAUL J.; MAINELIS, GEDIMINAS

    2014-01-01

    The potential for human exposure to engineered nanoparticles due to the use of nanotechnology-based consumer sprays (categorized as such by the Nanotechnology Consumer Products Inventory) is examined along with analogous products, which are not specified as nanotechnology-based (regular products). Photon correlation spectroscopy was used to obtain particle size distributions in the initial liquid products. Transmission electron microscopy was used to determine particle size, shape, and agglomeration of the particles. Realistic application of the spray products near the human breathing zone characterized airborne particles that are released during use of the sprays. Aerosolization of sprays with standard nebulizers was used to determine their potential for inhalation exposure. Electron microscopy detected the presence of nanoparticles in some nanotechnology-based sprays as well as in several regular products, whereas the photon correlation spectroscopy indicated the presence of particles <100 nm in all investigated products. During the use of most nanotechnology-based and regular sprays, particles ranging from 13 nm to 20 ?m were released, indicating that they could he inhaled and consequently deposited in all regions of the respiratory system. The results indicate that exposures to nanoparticles as well as micrometer-sized particles can be encountered owing to the use of nanotechnology-based sprays as well as regular spray products. PMID:21364702

  16. Combining group-based exposure therapy with prolonged exposure to treat U.S. Vietnam veterans with PTSD: a case study.

    PubMed

    Ready, David J; Vega, Edward M; Worley, Virginia; Bradley, Bekh

    2012-10-01

    Group-based exposure therapy (GBET) of 16-week duration was developed to treat combat-related posttraumatic stress disorder (PTSD) and decreased PTSD symptoms in 3 noncontrolled open trials with low attrition (0%-5%). Group-based exposure therapy has not produced as much PTSD symptom reduction as Prolonged Exposure (PE) within a U.S. Veterans Affairs PTSD treatment program, although PE had more dropouts (20%). This pilot study was of a model that combined key elements of GBET with components of PE in an effort to increase the effectiveness of a group-based treatment while reducing its length and maintaining low attrition. Twice per week, 8 Vietnam combat veterans with PTSD were treated for 12 weeks, with an intervention that included 2 within-group war trauma presentations per participant, 6 PE style individual imaginal exposure (IE) sessions per participant, daily listening to recorded IE sessions, and daily in vivo exposure exercises. All completed treatment and showed Significant reductions on all measures of PTSD with large effect sizes; 7 participants no longer met PTSD criteria on treating clinician administered interviews and a self-report measure at posttreatment. Significant reductions in depression with large effect sizes and moderate reductions in PTSD-related cognitions were also found. Most gains were maintained 6 months posttreatment. PMID:22965936

  17. 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

  18. Computational strategy for quantifying human pesticide exposure based upon a saliva measurement

    PubMed Central

    Timchalk, Charles; Smith, Jordan N.

    2015-01-01

    Quantitative exposure data is important for evaluating toxicity risk and biomonitoring is a critical tool for evaluating human exposure. Direct personal monitoring provides the most accurate estimation of a subject’s true dose, and non-invasive methods are advocated for quantifying exposure to xenobiotics. In this regard, there is a need to identify chemicals that are cleared in saliva at concentrations that can be quantified to support the implementation of this approach. This manuscript reviews the computational modeling approaches that are coupled to in vivo and in vitro experiments to predict salivary uptake and clearance of xenobiotics and provides additional insight on species-dependent differences in partitioning that are of key importance for extrapolation. The primary mechanism by which xenobiotics leave the blood and enter saliva involves paracellular transport, passive transcellular diffusion, or transcellular active transport with the majority of xenobiotics transferred by passive diffusion. The transcellular or paracellular diffusion of unbound chemicals in plasma to saliva has been computationally modeled using compartmental and physiologically based approaches. Of key importance for determining the plasma:saliva partitioning was the utilization of the Schmitt algorithm that calculates partitioning based upon the tissue composition, pH, chemical pKa, and plasma protein-binding. Sensitivity analysis identified that both protein-binding and pKa (for weak acids and bases) have significant impact on determining partitioning and species dependent differences based upon physiological variance. Future strategies are focused on an in vitro salivary acinar cell based system to experimentally determine and computationally predict salivary gland uptake and clearance for xenobiotics. It is envisioned that a combination of salivary biomonitoring and computational modeling will enable the non-invasive measurement of chemical exposures in human populations. PMID:26074822

  19. Interpreting PCB levels in breast milk using a physiologically based pharmacokinetic model to reconstruct the dynamic exposure of Italian women.

    PubMed

    Ulaszewska, Maria M; Ciffroy, Philippe; Tahraoui, Fazia; Zeman, Florence A; Capri, Ettore; Brochot, Céline

    2012-11-01

    Polychlorinated biphenyls (PCBs) are persistent contaminants suspected to cause adverse health effects in humans. As PCBs levels in food have not been monitored frequently in the past, modeling approaches based on environmental data have been proposed to predict the human dietary intake. In this work, we propose to improve these approaches by taking into account internal levels of PCBs in humans. This methodology is based on the analysis of biomonitoring data using exposure and physiologically based pharmacokinetic (PBPK) modeling to determine the most probable scenario of exposure. Breast milk concentrations were measured in Italian women for PCB-138, PCB-153 and PCB-180. For each congener, three exposure scenarios were derived and a PBPK model was used to relate the lifetime exposure to the breast milk levels. For the three PCBs, we determined the most probable scenario of exposure. Our results support the adequacy of the exposure and the PBPK models for PCB-180 and PCB-153, whereas we observed discrepancies between the models and the biomonitoring data for PCB-138. Our intake estimates are in good agreement with previous exposure assessments based solely on food contamination demonstrating the relevance of our approach to reconstruct accurately the exposure and to fill in data gaps on exposure. PMID:22760444

  20. 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,…

  1. Task division and tracking based on macro-micro manipulators system for discontinuous trajectory

    Microsoft Academic Search

    Chen Qijun; Wang Yuejuan; Chen Huitang

    2002-01-01

    Ibis paper presents a kind of strategy of task division to process the discontinuous trajectory tracking. Using cubic spline with string parameter to fit the discontinuous trajectory result in: (a) the desired trajectory for macro manipulator is continuous, of which, the discontinuous parts will be tracked by the micro manipulator; and (b) macro-micro manipulator - the redundant system can be

  2. Trajectory generation of robotic fingers based on tri-axial tactile data for cap screwing task

    Microsoft Academic Search

    Masahiro Ohka; Nobuyuki Morisawa; Hanafiah B. Yussof

    2009-01-01

    In a previous paper, we developed a robotic finger equipped with optical three-axis tactile sensors, of which the sensing cell can separately detect normal and shearing forces. With appropriate precision, the robotic finger was able to perform three tasks: scanning flat specimens to obtain the friction coefficient, following the contour of objects, and manipulating a parallelepiped case put on a

  3. A Knowledge Task-Based Framework for Design and Evaluation of Information Visualizations

    E-print Network

    Stasko, John T.

    30332-0280 ABSTRACT The design and evaluation of most current information visualization systems descend variable across users, data sets, and domains. In this paper, we discuss the notion of analytic gaps, which represent obstacles faced by visualizations in facilitating higher-level analytic tasks, such as decision

  4. 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…

  5. Customizable Retrieval Functions Based on User Tasks in the Cultural Heritage Domain

    Microsoft Academic Search

    Holger Brocks; Ulrich Thiel; Adelheit Stein; Andrea Dirsch-weigand

    2001-01-01

    The cultural heritage domain dealing with digital surrogates of rare and fragile historic artifacts is one of the most promising areas for establishing collaboratories, i.e. shared virtual working environments for groups of users. However, in order to be considered a useful tool, such a system must reflect and support the specific tasks which are typical for the domain. The system

  6. Touching base: The effect of participant and stimulus modulation factors on a haptic line bisection task

    Microsoft Academic Search

    Sylvia Hach; Simone Schütz-Bosbach

    2011-01-01

    Acquiring information about our environment through touch is vital in everyday life. Yet very little literature exists about factors that may influence haptic or tactile processing. Recent neuroimaging studies have reported haptic laterality effects that parallel those reported in the visual literature. With the use of a haptic variant of the classical line bisection task, the present study aimed to

  7. Touching base: The effect of participant and stimulus modulation factors on a haptic line bisection task

    Microsoft Academic Search

    Sylvia Hach; Simone Schütz-Bosbach

    2012-01-01

    Acquiring information about our environment through touch is vital in everyday life. Yet very little literature exists about factors that may influence haptic or tactile processing. Recent neuroimaging studies have reported haptic laterality effects that parallel those reported in the visual literature. With the use of a haptic variant of the classical line bisection task, the present study aimed to

  8. A Task Space Redundancy-Based Scheme for Motion Yixin Chen 2

    E-print Network

    Chen, Yixin

    parallel robot performing a 2- DOF tracking task. 1 Introduction A manipulator is kinematically redundant-effector. This ex- tra freedom offers many advantages over conventional nonredundant manipulators in robot planning]. For example, in welding, the positions of the welding rod are crucial to the perfor- mance while rotations

  9. Employee Involvement, Technology, and Evolution in Job Skills: A Task-Based Analysis

    Microsoft Academic Search

    Francis Green

    2011-01-01

    The author investigates the evolution of job skill distribution using task data derived from the U.K. Skills Surveys of 1997, 2001, and 2006, and the 1992 Employment Survey in Britain. He determines the extent to which employee involvement in the workplace and computer technologies promote the use of higher order cognitive and interactive skills. He finds that literacy, other communication

  10. Exposure and mindfulness based therapy for irritable bowel syndrome--an open pilot study.

    PubMed

    Ljótsson, Brjánn; Andréewitch, Sergej; Hedman, Erik; Rück, Christian; Andersson, Gerhard; Lindefors, Nils

    2010-09-01

    We conducted a study of a group therapy based on exposure and mindfulness in the treatment of irritable bowel syndrome (IBS). Out of 49 outpatients, most of whom were referred from gastroenterological clinics, 34 entered into the 10-week treatment. Patients were assessed before, immediately after and 6 months after treatment. The assessments consisted of a gastrointestinal symptom diary, self-report questionnaires covering quality of life, gastrointestinal specific anxiety, general functioning, and a psychiatric interview. At post-treatment, the mean reduction in symptoms was 41% and 50% of patients showed clinically significant improvement in symptom level. Patients also showed marked improvement on other outcome measures. Treatment gains were maintained at follow-up. The results support the use of exposure and mindfulness based strategies in the treatment of IBS, but further randomised studies are needed to confirm the efficacy of the treatment. PMID:20079485

  11. Occupational exposure to water based paint and symptoms from the skin and eyes.

    PubMed Central

    Wieslander, G; Norbäck, D; Edling, C

    1994-01-01

    Water based paints contain organic solvents and many additives, such as biocides, surfactants, pigments, binders, amines, and monomers. The chemical complexity may introduce new potential health hazards to house painters, in particular irritative and allergic disorders. This study was performed to compare how house painters experience work with water based paints or solvent based paints, and to evaluate whether exposure to water based paints increases mucous membrane and dermal symptoms among house painters. 255 male house painters aged 20 to 65 were invited to participate in the study. Controls were two industrial populations, in total 302 men, without exposure to water based paints. Self administered questionnaires were used to assess the painter's experiences of working with different types of paints and the occurrence of symptoms in the exposed and unexposed groups. Hygiene measurements were performed during normal working days when only water based paints and no solvent based paints were used. The painters were exposed to low concentrations of dust, metals, ammonia, formaldehyde, and volatile organic compounds. The work environment was considered better when working with water based paints than with solvent based paints. There were more complaints of frequent urination when working with water based paint. Taste or olfactory disturbances were less common. General as well as work related eye and skin irritation was more common among the exposed workers. For other symptoms no significant differences were found. The study indicates that the introduction of water based paints has improved the work environment for house painters. Water based paints cause less discomfort and airway irritation than the earlier solvent based paints. Adverse general health effects seem low. Some of the painters may have dermal symptoms caused by the components in water based paints. PMID:8130846

  12. 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

  13. Reading guided by automated graphical representations: How model-based text visualizations facilitate learning in reading comprehension tasks

    Microsoft Academic Search

    Pablo Pirnay-Dummer; Dirk Ifenthaler

    Our study integrates automated natural language-oriented assessment and analysis methodologies into feasible reading comprehension\\u000a tasks. With the newly developed T-MITOCAR toolset, prose text can be automatically converted into an association net which\\u000a has similarities to a concept map. The “text to graph” feature of the software is based on several parsing heuristics and\\u000a can be used both to assess the

  14. Solvent exposure and malignant lymphoma: a population-based case-control study in Germany

    Microsoft Academic Search

    Andreas Seidler; Matthias Möhner; Jürgen Berger; Birte Mester; Evelin Deeg; Gine Elsner; Alexandra Nieters; Nikolaus Becker

    2007-01-01

    AIMS: To analyze the relationship between exposure to chlorinated and aromatic organic solvents and malignant lymphoma in a multi-centre, population-based case-control study. METHODS: Male and female patients with malignant lymphoma (n = 710) between 18 and 80 years of age were prospectively recruited in six study regions in Germany (Ludwigshafen\\/Upper Palatinate, Heidelberg\\/Rhine-Neckar-County, Würzburg\\/Lower Frankonia, Hamburg, Bielefeld\\/Gütersloh, and Munich). For each

  15. Pesticide exposure and risk of Parkinson's disease: A family-based case-control study

    Microsoft Academic Search

    Dana B Hancock; Eden R Martin; Gregory M Mayhew; Jeffrey M Stajich; Rita Jewett; Mark A Stacy; Burton L Scott; Jeffery M Vance; William K Scott

    2008-01-01

    BACKGROUND: Pesticides and correlated lifestyle factors (e.g., exposure to well-water and farming) are repeatedly reported risk factors for Parkinson's disease (PD), but few family-based studies have examined these relationships. METHODS: Using 319 cases and 296 relative and other controls, associations of direct pesticide application, well-water consumption, and farming residences\\/occupations with PD were examined using generalized estimating equations while controlling for

  16. Development of a fluorescence-based sensor for rapid diagnosis of cyanide exposure.

    PubMed

    Jackson, Randy; Oda, Robert P; Bhandari, Raj K; Mahon, Sari B; Brenner, Matthew; Rockwood, Gary A; Logue, Brian A

    2014-02-01

    Although commonly known as a highly toxic chemical, cyanide is also an essential reagent for many industrial processes in areas such as mining, electroplating, and synthetic fiber production. The "heavy" use of cyanide in these industries, along with its necessary transportation, increases the possibility of human exposure. Because the onset of cyanide toxicity is fast, a rapid, sensitive, and accurate method for the diagnosis of cyanide exposure is necessary. Therefore, a field sensor for the diagnosis of cyanide exposure was developed based on the reaction of naphthalene dialdehyde, taurine, and cyanide, yielding a fluorescent ?-isoindole. An integrated cyanide capture "apparatus", consisting of sample and cyanide capture chambers, allowed rapid separation of cyanide from blood samples. Rabbit whole blood was added to the sample chamber, acidified, and the HCN gas evolved was actively transferred through a stainless steel channel to the capture chamber containing a basic solution of naphthalene dialdehyde (NDA) and taurine. The overall analysis time (including the addition of the sample) was <3 min, the linear range was 3.13-200 ?M, and the limit of detection was 0.78 ?M. None of the potential interferents investigated (NaHS, NH4OH, NaSCN, and human serum albumin) produced a signal that could be interpreted as a false positive or a false negative for cyanide exposure. Most importantly, the sensor was 100% accurate in diagnosing cyanide poisoning for acutely exposed rabbits. PMID:24383576

  17. Probabilistic modeling of percutaneous absorption for risk-based exposure assessments and transdermal drug delivery.

    SciTech Connect

    Ho, Clifford Kuofei

    2004-06-01

    Chemical transport through human skin can play a significant role in human exposure to toxic chemicals in the workplace, as well as to chemical/biological warfare agents in the battlefield. The viability of transdermal drug delivery also relies on chemical transport processes through the skin. Models of percutaneous absorption are needed for risk-based exposure assessments and drug-delivery analyses, but previous mechanistic models have been largely deterministic. A probabilistic, transient, three-phase model of percutaneous absorption of chemicals has been developed to assess the relative importance of uncertain parameters and processes that may be important to risk-based assessments. Penetration routes through the skin that were modeled include the following: (1) intercellular diffusion through the multiphase stratum corneum; (2) aqueous-phase diffusion through sweat ducts; and (3) oil-phase diffusion through hair follicles. Uncertainty distributions were developed for the model parameters, and a Monte Carlo analysis was performed to simulate probability distributions of mass fluxes through each of the routes. Sensitivity analyses using stepwise linear regression were also performed to identify model parameters that were most important to the simulated mass fluxes at different times. This probabilistic analysis of percutaneous absorption (PAPA) method has been developed to improve risk-based exposure assessments and transdermal drug-delivery analyses, where parameters and processes can be highly uncertain.

  18. Statistical modeling of occupational chlorinated solvent exposures for case–control studies using a literature-based database

    PubMed Central

    Hein, Misty J.; Waters, Martha A.; Ruder, Avima M.; Stenzel, Mark R.; Blair, Aaron; Stewart, Patricia A.

    2010-01-01

    Objectives: Occupational exposure assessment for population-based case–control studies is challenging due to the wide variety of industries and occupations encountered by study participants. We developed and evaluated statistical models to estimate the intensity of exposure to three chlorinated solvents—methylene chloride, 1,1,1-trichloroethane, and trichloroethylene—using a database of air measurement data and associated exposure determinants. Methods: A measurement database was developed after an extensive review of the published industrial hygiene literature. The database of nearly 3000 measurements or summary measurements included sample size, measurement characteristics (year, duration, and type), and several potential exposure determinants associated with the measurements: mechanism of release (e.g. evaporation), process condition, temperature, usage rate, type of ventilation, location, presence of a confined space, and proximity to the source. The natural log-transformed measurement levels in the exposure database were modeled as a function of the measurement characteristics and exposure determinants using maximum likelihood methods. Assuming a single lognormal distribution of the measurements, an arithmetic mean exposure intensity level was estimated for each unique combination of exposure determinants and decade. Results: The proportions of variability in the measurement data explained by the modeled measurement characteristics and exposure determinants were 36, 38, and 54% for methylene chloride, 1,1,1-trichloroethane, and trichloroethylene, respectively. Model parameter estimates for the exposure determinants were in the anticipated direction. Exposure intensity estimates were plausible and exhibited internal consistency, but the ability to evaluate validity was limited. Conclusions: These prediction models can be used to estimate chlorinated solvent exposure intensity for jobs reported by population-based case–control study participants that have sufficiently detailed information regarding the exposure determinants. PMID:20418277

  19. Myocardial infarction and occupational exposure to motor exhaust: a population-based case-control study in Sweden.

    PubMed

    Ilar, Anna; Lewné, Marie; Plato, Nils; Hallqvist, Johan; Alderling, Magnus; Bigert, Carolina; Hogstedt, Christer; Gustavsson, Per

    2014-07-01

    There is a well-established association between particulate urban air pollution and cardiovascular disease, but few studies have investigated the risk associated with occupational exposure to particles from motor exhaust. This study investigated the risk of myocardial infarction (MI) after occupational exposure to motor exhaust, using elemental carbon (EC) as a marker of exposure. A population-based case-control study of first-time non-lethal MI was conducted among Swedish citizens in ages 45-70 living in Stockholm County 1992-1994, including 1,643 cases and 2,235 controls. Working histories and data on potential confounders were collected by questionnaire and medical examination. The exposure to EC was assessed through a job-exposure matrix. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated by unconditional logistic regression. We investigated various exposure metrics: intensity, cumulative exposure and years since exposure. There was an exposure-response relation between the highest average exposure intensity during the work history and the risk of MI when adjusting for smoking and alcohol drinking (p for trend 0.034), with an OR of 1.30 (95% CI 0.99-1.71) in the highest tertile of exposure compared to the unexposed. An exposure-response pattern was observed in the analysis of years since exposure cessation among formerly exposed. Additional adjustments for markers of the metabolic syndrome reduced ORs and trends to non-significant levels, although this might be an over-adjustment since the metabolic syndrome may be part of the causal pathway. Occupational exposure to motor exhaust was associated with a moderately increased risk of MI. PMID:24981789

  20. Incidence of prenatal alcohol exposure in Prince Edward Island: a population-based descriptive study

    PubMed Central

    Bryanton, Janet; Boswall, Diane; McCarthy, Mary Jean; Fraser, Bonnie; Walsh, Donna; Freeman, Bridget; Koren, Gideon; Bigsby, Kathy

    2014-01-01

    Background Fetal alcohol spectrum disorder (FASD) is a leading preventable cause of neurodevelopmental disability in North America. The stigma associated with alcohol use and abuse during pregnancy makes it difficult to obtain information on prenatal alcohol use through self-reporting. We assessed the incidence of prenatal alcohol exposure in Prince Edward Island to facilitate future public health initiatives addressing FASD. Methods Prenatal alcohol exposure was examined via population-based collection of meconium and analysis of fatty acid ethyl esters (FAEEs). Fatty acid ethyl esters are nonoxidative metabolites of ethanol that are produced in the fetus. Meconium FAEE concentrations of 2.0 nmol/g or greater are indicative of frequent prenatal alcohol exposure during the last 2 trimesters of pregnancy. Samples were collected from 1307 neonates between Nov. 8, 2010, and Nov. 8, 2011, in hospitals in PEI, or from those born to mothers who resided in PEI but gave birth in Halifax, Nova Scotia. Samples were frozen and shipped for analysis. Fatty acid ethyl esters were analyzed by gas chromatography–mass spectrometry and quantified by means of deuterated internal standards. Results Of the 1307 samples collected, 1271 samples were successfully analyzed. Positive results for FAEEs were obtained in 3.1% (n = 39) of samples collected within the first 24 hours after birth. Interpretation Not all neonates exposed to heavy prenatal alcohol in utero will exhibit FASD; based on current estimates of predictive value for disease by exposure, our findings suggest that 1.3% of neonates born in PEI during this 1-year period will have FASD. In its application to an entire provincial birth cohort, this study successfully implemented a public health–centred approach for evaluating population-based risk of FASD, with implications for practice across Canada. PMID:25077128

  1. 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).

  2. Human Exposure to Selected Animal Neurocarcinogens: A Biomarker-Based Assessment and Implications for Brain Tumor Epidemiology

    PubMed Central

    Il’yasova, Dora; McCarthy, Bridget J.; Erdal, Serap; Shimek, Joanna; Goldstein, Jennifer; Doerge, Daniel R.; Myers, Steven R.; Vineis, Paolo; Wishnok, John S.; Swenberg, James A.; Bigner, Darell D.; Davis, Faith G.

    2013-01-01

    This review is based on the proceedings from the Second Lebow Conference held in Chicago in 2007. The conference concentrated on developing a framework for innovative studies in the epidemiology of environmental exposures, focusing specifically on the potential relationship with brain tumors. Researchers with different perspectives, including toxicology, pharmacokinetics, and epidemiological exposure assessment, exchanged information and ideas on the use of biomarkers of exposure in molecular epidemiology studies and summarized the current knowledge on methods and approaches for biomarker-based exposure assessment. This report presents the state of science regarding biomarker-based exposure assessment of the 4 most common neurocarcinogens: acrylamide, 1,3-butadiene, N-nitroso compounds, and polycyclic aromatic hydrocarbons. Importantly, these chemicals are also carcinogenic in other organs; therefore, this discussion is useful for environmental epidemiologists studying all cancer types. PMID:19466671

  3. Occupational exposures to Cd, Ni, and Cr modulate titers of antioxidized DNA base autoantibodies.

    PubMed Central

    Frenkel, K; Karkoszka, J; Cohen, B; Bara?ski, B; Jakubowski, M; Cosma, G; Taioli, E; Toniolo, P

    1994-01-01

    This study was undertaken to establish whether occupational exposures to derivatives of carcinogenic metals evoke inflammatory immune responses, as determined by the presence of elevated titers of antibodies (Ab) that recognize oxidized DNA bases. Sera obtained from the blood of steel welders (Delaware) and from workers of the Centra Ni-Cd Battery Factory (Pozna?, Poland) were analyzed by the enzyme-linked immunosorbent assay. To determine specific and nonspecific binding, an oxidized thymidine [5-hydroxymethyl-2'-deoxyuridine (HMdU)] coupled to bovine serum albumin (HMdU-BSA) as well as mock-coupled BSA (M-BSA) were used as antigens for coating the wells of microtiter plates. Titers of anti-HMdU Ab were significantly elevated in the high Cd and Ni exposure groups (18.3 +/- 3.2 vs 10.8 +/- 2.1 A492/microliters; p < 0.05). The sera of the groups with low exposures to Cd and Ni also had enhanced titers of those Ab but those increases were not statistically significant. Interestingly, the Ab titers present in the sera of controls for Cd and Ni exposures appear to be constant regardless of the protein content. In contrast, both lightly and heavily exposed subjects exhibited Ab titers that increased with increasing protein content. When 12 randomly selected workers (4 from each of the control, lightly, and heavily exposed groups) were outfitted with personal monitors, anti-HMdU Ab titers of those workers showed a significant difference between the groups with light (< 100 micrograms/m3) and heavy (> 200 micrograms/m3) exposures to Cd (9.8 +/- 3.7 vs 22.1 +/- 3.7 A492/microliters; p < 0.01) and Ni (11.7 +/- 1.4 vs 31.0 +/- 1.8; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7843102

  4. Diagnostic Ionizing Radiation Exposure in a Population-based Sample of Children with Inflammatory Bowel Diseases

    PubMed Central

    Palmer, Lena; Herfarth, Hans; Porter, Carol Q.; Fordham, Lynn A.; Sandler, Robert S.; Kappelman, Michael D.

    2009-01-01

    Background and Aims The degree of diagnostic radiation exposure in children with inflammatory bowel diseases (IBD) is largely unknown. Here we describe this exposure in a population-based sample of children with IBD and determine characteristics associated with moderate radiation exposure. Methods We ascertained radiological study use, demographic characteristics, IBD medication use, and the requirement for hospitalization, emergency department (ED) encounter, or inpatient GI surgery among children with IBD within a large insurance claims database. Characteristics associated with moderate radiation exposure (at least one computed tomography (CT) or three fluoroscopies over two years) were determined using logistic regression models. Results We identified 965 children with Crohn’s Disease (CD) and 628 with Ulcerative Colitis (UC). Over 24 months, 34% of CD subjects and 23% of UC subjects were exposed to moderate diagnostic radiation [odds ratio (OR) 1.71, 95% confidence interval (CI), 1.36–2.14]. CT accounted for 28% and 25% of all studies in CD and UC subjects, respectively. For CD subjects, moderate radiation exposure was associated with hospitalization (OR 4.89, 95% CI 3.37–7.09), surgery (OR 2.93, 95% CI 1.59–5.39), ED encounter (OR 2.65, 1.93–3.64 95% CI), oral steroids (OR 2.25, 95% CI 1.50–3.38), and budesonide (OR 1.80, 95% CI 1.10–3.06); an inverse association was seen with immunomodulator use (OR 0.67, 95% CI 0.47–0.97). Except for oral steroids and immunomodulators, similar relationships were seen in UC. Conclusion A substantial proportion of children with IBD are exposed to moderate amounts of radiation as a result of diagnostic testing. This high utilization may impart long-term risk given the chronic nature of the disease. PMID:19690524

  5. 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

  6. Adjustments of response threshold during task switching: a model-based functional magnetic resonance imaging study.

    PubMed

    Mansfield, Elise L; Karayanidis, Frini; Jamadar, Sharna; Heathcote, Andrew; Forstmann, Birte U

    2011-10-12

    Adjustment of response threshold for speed compared with accuracy instructions in two-choice decision-making tasks is associated with activation in the fronto-striatal network, including the pre-supplementary motor area (pre-SMA) and striatum (Forstmann et al., 2008). In contrast, increased response conservativeness is associated with activation of the subthalamic nucleus (STN) (Frank et al., 2007). We investigated the involvement of these regions in trial-by-trial adjustments of response threshold in humans, using a cued-trials task-switching paradigm. Fully and partially informative switch cues produced more conservative thresholds than repeat cues. Repeat cues were associated with higher activation in pre-SMA and striatum than switch cues. For all cue types, individual variability in response threshold was associated with activation level in pre-SMA, with higher activation linked to lower threshold setting. In the striatum, this relationship was found for repeat cues only. These findings support the notion that pre-SMA biases the striatum to lower response threshold under more liberal response regimens. In contrast, a high threshold for switch cues was associated with greater activation in right STN, consistent with increasing response caution under conservative response regimens. We conclude that neural models of response threshold adjustment can help explain executive control processes in task switching. PMID:21994385

  7. Ecological risk characterization based on exposure to contaminants through the Rocky Mountain Arsenal aquatic food chains

    SciTech Connect

    Toll, J.E.; Cothern, K.A.; Pavlou, S. [Enserch Environmental Corp., Bellevue, WA (United States); Tate, D.J. [Enserch Environmental Corp., Lakewood, CO (United States); Armstrong, J.P. [Rocky Mountain Arsenal, Commerce City, CO (United States)

    1994-12-31

    This paper describes ecological risk characterization methods and results for characterizing potential risk from exposure to bioaccumulative contaminants of concern (aldrin, dieldrin, endrin, DDT, DDE, and mercury) through the lake food chains at Rocky Mountain Arsenal (RMA). Aquatic risks were estimated for the bald eagle, great blue heron, shorebird, and water bird using a prey-tissue-concentration-based food web model. Methods for estimating missing tissue concentration data were developed on a case-by-case basis and will be described. A sediment-based food web model was also considered and the reasons for its rejection will be described. Generalizable insights from the aquatic ecological risk characterization will be discussed.

  8. Human Exposure to Selected Animal Neurocarcinogens: A Biomarker-Based Assessment and Implications for Brain Tumor Epidemiology

    Microsoft Academic Search

    Dora Ilyasova; Bridget J. McCarthy; Serap Erdal; Joanna Shimek; Jennifer Goldstein; Daniel R. Doerge; Steven R. Myers; Paolo Vineis; John S. Wishnok; James A. Swenberg; Darell D. Bigner; Faith G. Davis

    2009-01-01

    This review is based on the proceedings from the Second Lebow Conference, held in Chicago in 2007. The conference concentrated on developing a framework for innovative studies in the epidemiology of environmental exposures, focusing specifically on the potential relationship with brain tumors. Researchers with different perspectives, including toxicology, pharmacokinetics, and epidemiological exposure assessment, exchanged information and ideas on the use

  9. A New Stress-Based Model of Political Extremism: Personal Exposure to Terrorism, Psychological Distress, and Exclusionist Political Attitudes

    ERIC Educational Resources Information Center

    Canetti-Nisim, Daphna; Halperin, Eran; Sharvit, Keren; Hobfoll, Stevan E.

    2009-01-01

    Does exposure to terrorism lead to hostility toward minorities? Drawing on theories from clinical and social psychology, we propose a stress-based model of political extremism in which psychological distress--which is largely overlooked in political scholarship--and threat perceptions mediate the relationship between exposure to terrorism and…

  10. Effect of methodology, dilution, and exposure time on the tuberculocidal activity of glutaraldehyde-based disinfectants.

    PubMed Central

    Cole, E C; Rutala, W A; Nessen, L; Wannamaker, N S; Weber, D J

    1990-01-01

    The Association of Official Analytical Chemists (AOAC) test for assessing the tuberculocidal activity of disinfectants has been shown to be variable. A modified AOAC test, which substituted Middlebrook 7H9 broth as the primary subculture medium and used neutralization by dilution, was compared with the standard AOAC method to assess the mycobactericidal activity of three glutaraldehyde-based disinfectants at 20 degrees C and various exposure times. These changes had a marked effect on results, with the modified AOAC test providing more positive penicylinders per 10 replicates in 12 of the 13 comparisons that provided positive results. These differences were observed with both Mycobacterium bovis (ATCC 35743) and a clinical isolate of Mycobacterium tuberculosis. The effects of various exposure times to and dilutions of the glutaraldehyde-based disinfectants were also examined. The minimum exposure time needed to inactivate reliably M. bovis or M. tuberculosis with 2% glutaraldehyde was 20 min at 20 degrees C. Diluting 2% glutaraldehyde caused a significant decline in mycobactericidal activity. Modification of the standard AOAC test to improve its sensitivity in detecting the failure of disinfectants to inactivate mycobacteria is indicated. PMID:2116760

  11. Workgroup Report: Base Stations and Wireless Networks—Radiofrequency (RF) Exposures and Health Consequences

    PubMed Central

    Valberg, Peter A.; van Deventer, T. Emilie; Repacholi, Michael H.

    2007-01-01

    Radiofrequency (RF) waves have long been used for different types of information exchange via the airwaves—wireless Morse code, radio, television, and wireless telephony (i.e., construction and operation of telephones or telephonic systems). Increasingly larger numbers of people rely on mobile telephone technology, and health concerns about the associated RF exposure have been raised, particularly because the mobile phone handset operates in close proximity to the human body, and also because large numbers of base station antennas are required to provide widespread availability of service to large populations. The World Health Organization convened an expert workshop to discuss the current state of cellular-telephone health issues, and this article brings together several of the key points that were addressed. The possibility of RF health effects has been investigated in epidemiology studies of cellular telephone users and workers in RF occupations, in experiments with animals exposed to cell-phone RF, and via biophysical consideration of cell-phone RF electric-field intensity and the effect of RF modulation schemes. As summarized here, these separate avenues of scientific investigation provide little support for adverse health effects arising from RF exposure at levels below current international standards. Moreover, radio and television broadcast waves have exposed populations to RF for > 50 years with little evidence of deleterious health consequences. Despite unavoidable uncertainty, current scientific data are consistent with the conclusion that public exposures to permissible RF levels from mobile telephony and base stations are not likely to adversely affect human health. PMID:17431492

  12. Murine pulmonary responses after sub-chronic exposure to aluminum oxide-based nanowhiskers

    PubMed Central

    2012-01-01

    Background Aluminum oxide-based nanowhiskers (AO nanowhiskers) have been used in manufacturing processes as catalyst supports, flame retardants, adsorbents, or in ceramic, metal and plastic composite materials. They are classified as high aspect ratio nanomaterials. Our aim was to assess in vivo toxicity of inhaled AO nanowhisker aerosols. Methods Primary dimensions of AO nanowhiskers specified by manufacturer were 2–4?nm x 2800?nm. The aluminum content found in this nanomaterial was 30% [mixed phase material containing Al(OH)3 and AlOOH]. Male mice (C57Bl/6?J) were exposed to AO nanowhiskers for 4?hrs/day, 5?days/wk for 2 or 4 wks in a dynamic whole body exposure chamber. The whiskers were aerosolized with an acoustical dry aerosol generator that included a grounded metal elutriator and a venturi aspirator to enhance deagglomeration. Average concentration of aerosol in the chamber was 3.3?±?0.6?mg/m3 and the mobility diameter was 150?±?1.6?nm. Both groups of mice (2 or 4 wks exposure) were necropsied immediately after the last exposure. Aluminum content in the lung, heart, liver, and spleen was determined. Pulmonary toxicity assessment was performed by evaluation of bronchoalveolar lavage (BAL) fluid (enumeration of total and differential cells, total protein, activity of lactate dehydrogenase [LDH] and cytokines), blood (total and differential cell counts), lung histopathology and pulmonary mechanics. Results Following exposure, mean Al content of lungs was 0.25, 8.10 and 15.37??g/g lung (dry wt) respectively for sham, 2 wk and 4 wk exposure groups. The number of total cells and macrophages in BAL fluid was 2-times higher in animals exposed for 2 wks and 6-times higher in mice exposed for 4 wks, compared to shams (p?exposures to aluminum-oxide based nanowhiskers induced increased lung macrophages, but no inflammatory or toxic responses were observed. PMID:22713230

  13. Using Job-title Based Physical Exposures from O*NET in an Epidemiological Study of Carpal Tunnel Syndrome

    PubMed Central

    Evanoff, Bradley; Zeringue, Angelique; Franzblau, Alfred; Dale, Ann Marie

    2014-01-01

    Objective We studied associations between job title based measures of force and repetition and incident carpal tunnel syndrome (CTS). Background Job exposure matrices (JEMs) are not commonly used in studies of work-related upper extremity disorders. Methods We enrolled newly-hired workers into a prospective cohort study. We assigned a Standard Occupational Classification (SOC) code to each job held and extracted physical work exposure variables from the Occupational Information Network (O*NET). CTS case definition required both characteristic symptoms and abnormal median nerve conduction. Results 751 (67.8%) of 1107 workers completed follow-up evaluations. 31 subjects (4.4%) developed CTS during an average of 3.3 years of follow-up. Repetitive Motion, Static Strength, and Dynamic Strength from the most recent job held were all significant predictors of CTS when included individually as physical exposures in models adjusting for age, gender, and BMI. Similar results were found using time-weighted exposure across all jobs held during the study. Repetitive Motion, Static Strength, and Dynamic Strength were correlated, precluding meaningful analysis of their independent effects. Conclusion This study found strong relationships between workplace physical exposures assessed via a JEM and CTS, after adjusting for age, gender, and BMI. Though job title based exposures are likely to result in significant exposure misclassification, they can be useful for large population studies where more precise exposure data are not available. Application JEMs can be used as a measure of workplace physical exposures for some studies of musculoskeletal disorders. PMID:24669551

  14. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators

    PubMed Central

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam–energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  15. LC-MS/MS-based multibiomarker approaches for the assessment of human exposure to mycotoxins.

    PubMed

    Warth, Benedikt; Sulyok, Michael; Krska, Rudolf

    2013-07-01

    Mycotoxins are toxic fungal secondary metabolites that frequently contaminate food and feed worldwide, and hence represent a major hazard for food and feed safety. To estimate human exposure arising from contaminated food, so-called biomarker approaches have been developed as a complementary biomonitoring tool besides traditional food analysis. The first methods based on radioimmunoassays and enzyme-linked immunosorbent assays as well as on liquid chromatography were developed in the late 1980s and early 1990s for the carcinogenic aflatoxins and in the last two decades further tailor-made methods for some major mycotoxins have been published. Since 2010, there has been a clear trend towards the development and application of multianalyte methods based on liquid chromatography-electrospray ionization tandem mass spectrometry for assessment of mycotoxin exposure made possible by the increased sensitivity and selectivity of modern mass spectrometry instrumentation and sophisticated sample cleanup approaches. With use of these advanced methods, traces of mycotoxins and relevant breakdown and conjugation products can be quantified simultaneously in human urine as so-called biomarkers and can be used to precisely describe the real exposure, toxicokinetics, and bioavailability of the toxins present. In this article, a short overview and comparison of published multibiomarker methods focusing on the determination of mycotoxins and relevant excretion products in human urine is presented. Special attention is paid to the main challenges when analyzing these toxic food contaminants in urine, i.e., very low analyte concentrations, appropriate sample preparation, matrix effects, and a lack of authentic, NMR-confirmed calibrants and reference materials. Finally, the progress in human exposure assessment studies facilitated by these analytical methods is described and an outlook on probable developments and possibilities is presented. PMID:23774829

  16. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators.

    PubMed

    Kim, Myung-Hee Y; Rusek, Adam; Cucinotta, Francis A

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and (4)He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  17. Cigarette Filter-based Assays as Proxies for Toxicant Exposure and Smoking Behavior A Literature Review

    PubMed Central

    Pauly, John L.; O’Connor, Richard J.; Paszkiewicz, Geraldine M.; Cummings, K. Michael; Djordjevic, Mirjana V.; Shields, Peter G.

    2009-01-01

    Background Cigarettes are being marketed with filters that differ in composition and design. The filters have different toxicant trapping efficiency and smoking stains reflect variations in smoking behavior. Presented herein are the results of a structured literature review that was performed to identify cigarette filter-based assays that may serve as proxies for mouth-level exposure and assessing smoking methods. Methods A search of the published scientific literature and internal tobacco company documents from 1954 to 2009 was performed. Results The literature search identified diverse schemes for assessing cigarette filters, including visual inspection and digital imaging of smoked-stained spent filters, and quantitative determinations for total particulate matter (TPM), nicotine, and solanesol. The results also showed that: (a) there is sufficient data to link filter-based chemical measures to standardized smoking machine-measured yields of tar and nicotine; (b) TPM eluted from filters or in chemical digest of filters can be used to estimate the efficiency of the filter for trapping smoke solids; (c) visual and digital inspection of spent filters are useful as indicators of variations in smoking behaviors; and (d) there is a correlation between solanesol and nicotine measured in filters and exposure biomarkers in smokers. Conclusions The cigarette filter may prove useful in estimating smoking behaviors such as filter vent blocking and puffing intensity, and may have utility as proxy measures of mouth-level smoke exposure in clinical trials. Additional investigations are needed to compare the different proposed assay schemes and the assay results with measurements of human biomarker assays of smoke exposure. PMID:19959679

  18. The Effects of Synchronous Text-Based Computer-Mediated Communication Tasks on the Development of L2 and Academic Literacy: A Mixed Methods Study

    ERIC Educational Resources Information Center

    Li, Jinrong

    2012-01-01

    The dissertation examines how synchronous text-based computer-mediated communication (SCMC) tasks may affect English as a Second Language (ESL) learners' development of second language (L2) and academic literacy. The study is motivated by two issues concerning the use of SCMC tasks in L2 writing classes. First, although some of the alleged…

  19. Ethylene glycol exposure: an evidence-based consensus guideline for out-of-hospital management.

    PubMed

    Caravati, E Martin; Erdman, Andrew R; Christianson, Gwenn; Manoguerra, Anthony S; Booze, Lisa L; Woolf, Alan D; Olson, Kent R; Chyka, Peter A; Scharman, Elizabeth J; Wax, Paul M; Keyes, Daniel C; Troutman, William G

    2005-01-01

    In 2002, poison centers in the US reported 5816 human exposures to ethylene glycol. A guideline that effectively determines the threshold dose for emergency department referral and need for pre-hospital decontamination could potentially avoid unnecessary emergency department visits, reduce health care costs, optimize patient outcome, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create this guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the primary author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the out-of-hospital triage and initial management of patients with a suspected exposure to ethylene glycol by (1) describing the process by which the exposure might be evaluated, (2) identifying the key decision elements in managing the case, (3) providing clear and practical recommendations that reflect the current state of knowledge, and (4) identifying needs for research. This guideline is based on an assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and health professionals providing care, considering all of the circumstances involved. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. (1) A patient with exposure due to suspected self-harm, misuse, or potentially malicious administration should be referred to an emergency department immediately regardless of the dose reported (Grade D). (2) Patients with inhalation exposures will not develop systemic toxicity and can be managed out-of-hospital if asymptomatic (Grade B). Patients with clinically significant mucous membrane irritation should be referred for evaluation (Grade D). (3) Decontamination of dermal exposures should include routine cleansing with mild soap and water. Removal of contact lenses and immediate irrigation with room temperature tap water is recommended for ocular exposures. All patients with symptoms of eye injury should be referred for an ophthalmologic exam (Grade D). (4) Patients with symptoms of ethylene glycol poisoning should be referred immediately for evaluation regardless of the reported dose (Grade C). (5) The absence of symptoms shortly after ingestion does not exclude a potentially toxic dose and should not be used as a triage criterion (Grade C). (6) Adults who ingest a "swallow" (10-30 mL), children who ingest more than a witnessed taste or lick, or if the amount is unknown of most ethylene glycol products should be referred immediately for evaluation. The potential toxic volume of dilute solutions (e.g., concentration <20%) is larger and can be estimated by a formula in the text (Grade C). (7) A witnessed taste or lick only by a child, or an adult who unintentionally drinks and then expectorates the product without swallowing, does not need referral (Grade C). (8) Referral is not needed if it has been >24 hours since a potentially toxic unintentional exposure, the patient has been asymptomatic, and no alcohol was co-ingested (Grade D). (9) Gastrointestinal decontamination with ipecac syrup, gastric lavage or activated charcoal is not recommended. Transportation to an emergency department should not be delayed for any decontamination procedures (Grade D). (10) Patients meeting referral criteria should be evaluated at a hospital emergency department rather than a clinic. A facility that can quickly obtain an ethylene glycol serum concentration and has alcohol or fomepizole therapy available is preferred. This referral should be guided by local poison center procedures and community resources (Grade D). (11) The administration of alcohol, fomepizole, thiamine, or pyridoxine is n

  20. Grid Task Execution

    NASA Technical Reports Server (NTRS)

    Hu, Chaumin

    2007-01-01

    IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

  1. 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…

  2. MICA-AIR: A PARTICIPANT-BASED APPROACH TO EXPOSURE ASSESSMENT IN EPIDEMIOLOGIC AND COMMUNITY HEALTH STUDIES

    EPA Science Inventory

    Objective. Epidemiologic and community health studies of traffic-related air pollution and childhood asthma have been limited by resource intensive exposure assessment techniques. The current study utilized a novel participant-based approach to collect air monitoring data f...

  3. Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing based on Occupational Exposure Potential

    EPA Science Inventory

    Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. We reviewed published ENM concentr...

  4. Classification effects of real and imaginary movement selective attention tasks on a P300-based brain-computer interface

    NASA Astrophysics Data System (ADS)

    Salvaris, Mathew; Sepulveda, Francisco

    2010-10-01

    Brain-computer interfaces (BCIs) rely on various electroencephalography methodologies that allow the user to convey their desired control to the machine. Common approaches include the use of event-related potentials (ERPs) such as the P300 and modulation of the beta and mu rhythms. All of these methods have their benefits and drawbacks. In this paper, three different selective attention tasks were tested in conjunction with a P300-based protocol (i.e. the standard counting of target stimuli as well as the conduction of real and imaginary movements in sync with the target stimuli). The three tasks were performed by a total of 10 participants, with the majority (7 out of 10) of the participants having never before participated in imaginary movement BCI experiments. Channels and methods used were optimized for the P300 ERP and no sensory-motor rhythms were explicitly used. The classifier used was a simple Fisher's linear discriminant. Results were encouraging, showing that on average the imaginary movement achieved a P300 versus No-P300 classification accuracy of 84.53%. In comparison, mental counting, the standard selective attention task used in previous studies, achieved 78.9% and real movement 90.3%. Furthermore, multiple trial classification results were recorded and compared, with real movement reaching 99.5% accuracy after four trials (12.8 s), imaginary movement reaching 99.5% accuracy after five trials (16 s) and counting reaching 98.2% accuracy after ten trials (32 s).

  5. Odor valence linearly modulates attractiveness, but not age assessment, of invariant facial features in a memory-based rating task.

    PubMed

    Seubert, Janina; Gregory, Kristen M; Chamberland, Jessica; Dessirier, Jean-Marc; Lundström, Johan N

    2014-01-01

    Scented cosmetic products are used across cultures as a way to favorably influence one's appearance. While crossmodal effects of odor valence on perceived attractiveness of facial features have been demonstrated experimentally, it is unknown whether they represent a phenomenon specific to affective processing. In this experiment, we presented odors in the context of a face battery with systematic feature manipulations during a speeded response task. Modulatory effects of linear increases of odor valence were investigated by juxtaposing subsequent memory-based ratings tasks--one predominantly affective (attractiveness) and a second, cognitive (age). The linear modulation pattern observed for attractiveness was consistent with additive effects of face and odor appraisal. Effects of odor valence on age perception were not linearly modulated and may be the result of cognitive interference. Affective and cognitive processing of faces thus appear to differ in their susceptibility to modulation by odors, likely as a result of privileged access of olfactory stimuli to affective brain networks. These results are critically discussed with respect to potential biases introduced by the preceding speeded response task. PMID:24874703

  6. Lifelong physical activity and executive functions in older age assessed by memory based task switching.

    PubMed

    Gajewski, Patrick D; Falkenstein, Michael

    2015-07-01

    Aging is accompanied by compromised executive control. Training studies point to beneficial effects of physical activity on executive functions. Here, we investigate the relationship between lifelong habitual physical activity (about 50 years) and switch ability in healthy seniors. Participants switched among three tasks in a memorized task sequence. Mixing costs for speed were lower in habitually active than low active participants whereas switch costs were not affected. Active participants revealed also lower mixing and switch costs for accuracy. These parameters were negatively correlated with the self-reported level of physical activity. The frontal CNV was smaller in the active than low active group. In contrast, in the target-locked ERPs active individuals showed an earlier P2, a larger frontocentral N2 and the typical pattern of smaller P3b in switch than non-switch trials relative to low-active individuals. These data suggest that lifelong physical activity is associated with faster recall of stimulus-response sets (P2), enhanced response selection during interference processing (N2) and working memory updating (P3b) leading to lower mixing and switch costs. PMID:25937323

  7. An Automated, Adaptive Framework for Optimizing Preprocessing Pipelines in Task-Based Functional MRI

    PubMed Central

    Churchill, Nathan W.; Spring, Robyn; Afshin-Pour, Babak; Dong, Fan; Strother, Stephen C.

    2015-01-01

    BOLD fMRI is sensitive to blood-oxygenation changes correlated with brain function; however, it is limited by relatively weak signal and significant noise confounds. Many preprocessing algorithms have been developed to control noise and improve signal detection in fMRI. Although the chosen set of preprocessing and analysis steps (the “pipeline”) significantly affects signal detection, pipelines are rarely quantitatively validated in the neuroimaging literature, due to complex preprocessing interactions. This paper outlines and validates an adaptive resampling framework for evaluating and optimizing preprocessing choices by optimizing data-driven metrics of task prediction and spatial reproducibility. Compared to standard “fixed” preprocessing pipelines, this optimization approach significantly improves independent validation measures of within-subject test-retest, and between-subject activation overlap, and behavioural prediction accuracy. We demonstrate that preprocessing choices function as implicit model regularizers, and that improvements due to pipeline optimization generalize across a range of simple to complex experimental tasks and analysis models. Results are shown for brief scanning sessions (<3 minutes each), demonstrating that with pipeline optimization, it is possible to obtain reliable results and brain-behaviour correlations in relatively small datasets. PMID:26161667

  8. Estimating a Reasonable Patient Panel Size for Primary Care Physicians With Team-Based Task Delegation

    PubMed Central

    Altschuler, Justin; Margolius, David; Bodenheimer, Thomas; Grumbach, Kevin

    2012-01-01

    PURPOSE Primary care faces the dilemma of excessive patient panel sizes in an environment of a primary care physician shortage. We aimed to estimate primary care panel sizes under different models of task delegation to nonphysician members of the primary care team. METHODS We used published estimates of the time it takes for a primary care physician to provide preventive, chronic, and acute care for a panel of 2,500 patients, and modeled how panel sizes would change if portions of preventive and chronic care services were delegated to nonphysician team members. RESULTS Using 3 assumptions about the degree of task delegation that could be achieved (77%, 60%, and 50% of preventive care, and 47%, 30%, and 25% of chronic care), we estimated that a primary care team could reasonably care for a panel of 1,947, 1,523, or 1,387 patients. CONCLUSIONS If portions of preventive and chronic care services are delegated to nonphysician team members, primary care practices can provide recommended preventive and chronic care with panel sizes that are achievable with the available primary care workforce. PMID:22966102

  9. Study of objective evaluation indicators of 3D visual fatigue based on RDS related tasks

    NASA Astrophysics Data System (ADS)

    Huang, Yi; Liu, Yue; Zou, Bochao; Wang, Yongtian; Cheng, Dewen

    2015-03-01

    Three dimensional (3D) displays have witnessed rapid progress in recent years because of its highly realistic sensation and sense of presence to humanist users. However, the comfort issues of 3D display are often reported and thus restrict its wide applications. In order to study the objective evaluation indicators associated with 3D visual fatigue, an experiment is designed in which subjects are required to accomplish a task realized with random dot stereogram (RDS). The aim of designing the task is to induce 3D visual fatigue of subjects and exclude the impacts of monocular depth cues. The visual acuity, critical flicker frequency (CFF), reaction time and correct rate of subjects during the experiment are recorded and analyzed. Correlation of the experimental data with the subjective evaluation scores is studied to find which indicator is closely related to 3D visual fatigue. Analysis of the experimental data shows that the trends of the correct rate are in line with the result of subjective evaluation.

  10. 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.

  11. Evidence-based patient decontamination: an integral component of mass exposure chemical incident planning and response.

    PubMed

    Leary, Adam D; Schwartz, Michael D; Kirk, Mark A; Ignacio, Joselito S; Wencil, Elaine B; Cibulsky, Susan M

    2014-06-01

    Decontaminating patients who have been exposed to hazardous chemicals can directly benefit the patients' health by saving lives and reducing the severity of toxicity. While the importance of decontaminating patients to prevent the spread of contamination has long been recognized, its role in improving patient health outcomes has not been as widely appreciated. Acute chemical toxicity may manifest rapidly-often minutes to hours after exposure. Patient decontamination and emergency medical treatment must be initiated as early as possible to terminate further exposure and treat the effects of the dose already absorbed. In a mass exposure chemical incident, responders and receivers are faced with the challenges of determining the type of care that each patient needs (including medical treatment, decontamination, and behavioral health support), providing that care within the effective window of time, and protecting themselves from harm. The US Department of Health and Human Services and Department of Homeland Security have led the development of national planning guidance for mass patient decontamination in a chemical incident to help local communities meet these multiple, time-sensitive health demands. This report summarizes the science on which the guidance is based and the principles that form the core of the updated approach. PMID:24867089

  12. Resistance to freshwater exposure in White Sea Littorina spp. II: Acid-base regulation.

    PubMed

    Sokolova, I M; Bock, C; Pörtner, H O

    2000-03-01

    Parameters of acid-base and energy status were studied by in vivo 31P-nuclear magnetic resonance spectroscopy in three White Sea Littorina spp. (L. littorea, L. saxatilis and L. obtusata) during prolonged anaerobiosis in freshwater. Intracellular pH decreased significantly, especially during the early period of anaerobiosis, but later the decrease in intracellular pH slowed down considerably, suggesting a capacity for intracellular pH regulation in all three species. There was a trend for intracellular pH to fall most rapidly in the least freshwater-resistant species, L. obtusata, as compared to the most resistant, L. littorea. Non-bicarbonate, non-phosphate buffer values estimated by the homogenate technique were similar in the three studied species (28-37 mmol pH(-1) kg(-1) wet weight) and did not change during freshwater exposure. The CaCO3 buffer value of the foot tissues was considerably higher (171-218 mmol pH(-1) kg(-1) wet weight) and decreased significantly during freshwater exposure. The contribution of the multiple tissue buffering systems to intracellular pH regulation in Littorina spp. shifts between different stages of freshwater exposure. Initially, the non-bicarbonate, non-phosphate tissue buffering system seems to be of major importance for metabolic proton buffering at intracellular pH between 7.5 and 7.0. During later stages of anaerobiosis and at lower intracellular pH, the CaCO3 buffer is involved in proton buffering. Decrease in the CaCO3 buffer value during freshwater exposure was in quantitative agreement with the amount of metabolic protons buffered, thus suggesting that CaCO3 tissue stores may serve as a major buffering system during prolonged anaerobiosis in Littorina spp. PMID:10791570

  13. Population-Based Biomonitoring of Exposure to Organophosphate and Pyrethroid Pesticides in New York City

    PubMed Central

    Jacobson, J. Bryan; Kass, Daniel; Barr, Dana Boyd; Davis, Mark; Calafat, Antonia M.; Aldous, Kenneth M.

    2013-01-01

    Background: Organophosphates and pyrethroids are the most common classes of insecticides used in the United States. Widespread use of these compounds to control building infestations in New York City (NYC) may have caused higher exposure than in less-urban settings. Objectives: The objectives of our study were to estimate pesticide exposure reference values for NYC and identify demographic and behavioral characteristics that predict exposures. Methods: The NYC Health and Nutrition Examination Survey was a population-based, cross-sectional study conducted in 2004 among adults ? 20 years of age. It measured urinary concentrations of organophosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and diethyldithiophosphate] in 883 participants, and pyrethroid metabolites [3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-DCCA), 4-fluoro-3-phenoxybenzoic acid, and cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid] in 1,452 participants. We used multivariable linear regression to estimate least-squares geometric mean total dialkylphospate (?DAP) and 3-PBA concentrations across categories of predictors. Results: The dimethyl organophosphate metabolites had the highest 95th percentile concentrations (87.4 ?g/L and 74.7 ?g/L for DMP and DMTP, respectively). The highest 95th percentiles among pyrethroid metabolites were measured for 3-PBA and trans-DCCA (5.23 ?g/L and 5.94 ?g/L, respectively). Concentrations of ?DAP increased with increasing age, non-Hispanic white or black compared with Hispanic race/ethnicity, professional pesticide use, and increasing frequency of fruit consumption; they decreased with non-green vegetable consumption. Absolute differences in geometric mean urinary 3-PBA concentrations across categories of predictors were too small to be meaningful. Conclusion: Estimates of exposure to pyrethroids and dimethyl organophosphates were higher in NYC than in the United States overall, underscoring the importance of considering pest and pesticide burdens in cities when formulating pesticide use regulations. Citation: McKelvey W, Jacobson JB, Kass D, Barr DB, Davis M, Calafat AM, Aldous KM. 2013. Population-based biomonitoring of exposure to organophosphate and pyrethroid pesticides in New York City. Environ Health Perspect 121:1349–1356;?http://dx.doi.org/10.1289/ehp.1206015 PMID:24076605

  14. Task Analysis: A Proactive Paradigm.

    ERIC Educational Resources Information Center

    Cipriano, Robert E.

    A sequential and developmental curriculum design is conceptualized, based on task analysis. Task analysis is a detailed inquiry into actions undertaken in performing specific tasks or jobs. Baseline data form a database on which education and training programs are designed, produced, and evaluated. The following are sources of information for task

  15. A novel approach to model exposure of coastal-marine ecosystems to riverine flood plumes based on remote sensing techniques.

    PubMed

    Álvarez-Romero, Jorge G; Devlin, Michelle; Teixeira da Silva, Eduardo; Petus, Caroline; Ban, Natalie C; Pressey, Robert L; Kool, Johnathan; Roberts, Jason J; Cerdeira-Estrada, Sergio; Wenger, Amelia S; Brodie, Jon

    2013-04-15

    Increased loads of land-based pollutants are a major threat to coastal-marine ecosystems. Identifying the affected marine areas and the scale of influence on ecosystems is critical to assess the impacts of degraded water quality and to inform planning for catchment management and marine conservation. Studies using remotely-sensed data have contributed to our understanding of the occurrence and influence of river plumes, and to our ability to assess exposure of marine ecosystems to land-based pollutants. However, refinement of plume modeling techniques is required to improve risk assessments. We developed a novel, complementary, approach to model exposure of coastal-marine ecosystems to land-based pollutants. We used supervised classification of MODIS-Aqua true-color satellite imagery to map the extent of plumes and to qualitatively assess the dispersal of pollutants in plumes. We used the Great Barrier Reef (GBR), the world's largest coral reef system, to test our approach. We combined frequency of plume occurrence with spatially distributed loads (based on a cost-distance function) to create maps of exposure to suspended sediment and dissolved inorganic nitrogen. We then compared annual exposure maps (2007-2011) to assess inter-annual variability in the exposure of coral reefs and seagrass beds to these pollutants. We found this method useful to map plumes and qualitatively assess exposure to land-based pollutants. We observed inter-annual variation in exposure of ecosystems to pollutants in the GBR, stressing the need to incorporate a temporal component into plume exposure/risk models. Our study contributes to our understanding of plume spatial-temporal dynamics of the GBR and offers a method that can also be applied to monitor exposure of coastal-marine ecosystems to plumes and explore their ecological influences. PMID:23500022

  16. From Task List to Curriculum: A Teacher's Guide to Outcome-Based Curriculum. Second Edition.

    ERIC Educational Resources Information Center

    Brookhart, Donna; McGuire, Pat

    This guide is designed to assist the classroom teacher through all the major phases of development of an outcome-based curriculum. It is intended to aid in modifying a conventional curriculum to an outcome-based (competency-based) curriculum (OBC), building a course or program around an outcome-based model, revising curriculum toward an…

  17. Occupational Exposure to Mercury: Air Exposure Assessment and Biological Monitoring based on Dispersive Ionic Liquid-Liquid Microextraction

    PubMed Central

    SHIRKHANLOO, Hamid; GOLBABAEI, Farideh; HASSANI, Hamid; EFTEKHAR, Farrokh; KIAN, Mohammad Javad

    2014-01-01

    Abstract Background Exposure to mercury (Hg) as a heavy metal can cause health effects. The objective of this study was to assess occupational exposure to Hg in a chlor-alkali petrochemical industry in Iran by determining of Hg concentrations in air, blood and urine samples. Methods The study was performed on 50 exposed subjects and 50 unexposed controls. Air samples were collected in the breathing zone of exposed subjects, using hopcalite sorbents. Analysis was performed using a cold vapor atomic absorption spectrophotometer (CV-AAS) according to NIOSH analytical method 6009. For all participants, blood and urine samples were collected and then transferred into sterile glass tubes. After micro-extraction with ionic liquid and back extraction with nitric acid, Hg concentrations in blood and urine samples were determined by CV-AAS. Results The mean concentration of air Hg was 0.042± 0.003 mg/m3. The mean concentrations of Hg in blood and urine samples of exposed subjects were significantly higher than unexposed controls (22.41± 12.58 versus 1.19± 0.95 ?g/l and 30.61± 10.86 versus 1.99± 1.34 ?g/g creatinine, respectively). Correlation of air Hg with blood Hg, urine Hg and blood Hg-urine Hg ratio were significant statistically (P< 0.05). Conclusions The values of Hg in blood and urine samples of chlor-alkali workers were considerably high. Correlation coefficients showed that blood Hg and blood Hg-urine Hg ratio are better indicators than urine Hg for assessing occupationally exposed workers in terms of current exposure assessment.

  18. Threshold limit values, permissible exposure limits, and feasibility: The bases for exposure limits in the United States

    SciTech Connect

    Rappaport, S.M. (Univ. of North Carolina, Chapel Hill (United States))

    1993-01-01

    The development of exposure limits in the United States has always relied heavily upon the threshold limit values (TLVs) developed by the American Conference of Governmental Industrial Hygienists (ACGIH). In fact, the TLVs were adopted as official exposure limits by the Occupational Safety and Health Administration (OSHA) in 1972 and 1989. Given the continuing importance of the ACGIH limits, this paper compares the basis of the TLVs with that employed by OSHA de novo in its 12 new permissible exposure limits (PELs). Using benzene as an example, it is shown that OSHA's new PELs have been established following a rigorous assessment of the inherent risks and the feasibility of instituting the limit. The TLVs, on the other hand, have been developed by ad hoc procedures and appear to have traditionally reflected levels thought to be achievable at the time. However, this might be changing. Analysis of the historical reductions of TLVs, for 27 substances on the 1991-1992 list of intended changes, indicates smaller reductions in the past (median reduction of 2.0-2.5-fold between 1946 and 1988) compared to those currently being observed (median reduction of 7.5-fold between 1989 and 1991). Further analysis suggests a more aggressive policy of the ACGIH regarding TLVs for carcinogens but not for substances that produce effects other than cancer. Regardless of whether the basis of the TLVs has changed recently, it would take a relatively long time for the impact of any change to be felt, since the median age of the 1991-1992 TLVs is 16.5 years, and 75% of these limits are more than 10 years old. The implications of OSHA's continued reliance on the TLVs as a means of updating its PELs are discussed, and four alternatives are presented to the ACGIH regarding the future of its activities related to exposure limits. It is concluded that new mechanisms are needed for OSHA to update its PELs in a timely fashion so that the TLVs will not be adopted by default in the future.

  19. Separation of fission products based on ionic liquids: Task-specific ionic liquids containing an aza-crown ether fragment

    SciTech Connect

    Luo, Huimin [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL; Bonnesen, Peter V [ORNL] [ORNL; Buchanan III, A C [ORNL] [ORNL

    2005-01-01

    A new class of task-specific ionic liquids (TSILs) based on the covalent attachment of imidazolium cations to a monoaza-crown ether fragment has been synthesized and characterized. The efficacy of these TSILs for the biphasic extraction of Cs(+) and Sr(2+) from aqueous solutions has been evaluated. The extraction properties of these TSILs can be influenced by the structures of the covalently attached imidazolium cations, which highlight the possibilities to enhance or tune the selectivities of crown ethers toward target ionic species through the covalent coupling with the imidazolium cations. (c) 2005 Elsevier B.V. All rights reserved.

  20. Embrittlement of nickel-, cobalt-, and iron-base superalloys by exposure to hydrogen

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Five nickel-base alloys (Inconel 718, Udimet 700, Rene 41, Hastelloy X, and TD-NiCr), one cobalt-base alloy (L-605), and an iron-base alloy (A-286) were exposed in hydrogen at 0.1 MN/sq m (15 psi) at several temperatures in the range from 430 to 980 C for as long as 1000 hours. These alloys were embrittled to varying degrees by such exposures in hydrogen. Embrittlement was found to be: (1) sensitive to strain rate, (2) reversible, (3) caused by large concentrations of absorbed hydrogen, and (4) not associated with any detectable microstructural changes in the alloys. These observations are consistent with a mechanism of internal reversible hydrogen embrittlement.

  1. Effects of Periodic Task-Specific Test Feedback on Physical Performance in Older Adults Undertaking Band-Based Resistance Exercise

    PubMed Central

    Islam, Mohammod Monirul; Watanabe, Ryuji; Taaffe, Dennis R.

    2014-01-01

    The purpose of this study was to determine the effects of periodic task-specific test feedback on performance improvement in older adults undertaking community- and home-based resistance exercises (CHBRE). Fifty-two older adults (65–83 years) were assigned to a muscular perfsormance feedback group (MPG, n = 32) or a functional mobility feedback group (FMG, n = 20). Both groups received exactly the same 9-week CHBRE program comprising one community-based and two home-based sessions per week. Muscle performance included arm curls and chair stands in 30 seconds, while functional mobility was determined by the timed up and go (TUG) test. MPG received fortnightly test feedback only on muscle performance and FMG received feedback only on the TUG. Following training, there was a significant (P < 0.05) interaction for all performance tests with MPG improving more for the arm curls (MPG 31.4%, FMG 15.9%) and chair stands (MPG 33.7%, FMG 24.9%) while FMG improved more for the TUG (MPG-3.5%, FMG-9.7%). Results from this nonrandomized study suggest that periodic test feedback during resistance training may enhance task-specific physical performance in older persons, thereby augmenting reserve capacity or potentially reducing the time required to recover functional abilities. PMID:24616808

  2. Assessing Visual Arts Talents of Hong Kong Chinese Gifted Students: The Development of the Impossible Figures Task

    ERIC Educational Resources Information Center

    Chan, David W.

    2008-01-01

    The Impossible Figures Task (IFT-28), which consisted of 28 possible and impossible figures assembled for brief exposure and recognition, was completed by 297 Hong Kong Chinese gifted students. Expert judges (N = 2) rated these students' drawing abilities based on their performance on 2 drawing tasks adapted from Clark's Drawing Abilities Test…

  3. Quantitative exposure assessment: application of physiologically-based pharmacokinetic (PBPK) modeling of low-dose, long-term exposures of organic acid toxicant in the brain

    Microsoft Academic Search

    Chung S Kim; Jennifer A Sandberg; William Slikker; Zbigniew Binienda; Paul M Schlosser; Tucker A Patterson

    2001-01-01

    Our objective was to construct a physiologically-based pharmacokinetic (PBPK) model describing the kinetic behavior of 2,4-dichlorophenoxyacetic acid (2,4-D) on rats after long-term exposures to low doses. Our study demonstrated the model's ability to simulate uptake of 2,4-D in discrete areas of the rat brain. The model was derived from the generic PBPK model that was first developed for high-dose, single

  4. Using a representative sample of workers for constructing the SUMEX French general population based job-exposure matrix

    PubMed Central

    Gueguen, A; Goldberg, M; Bonenfant, S; Martin, J

    2004-01-01

    Background: Job-exposure matrices (JEMs) applicable to the general population are usually constructed by using only the expertise of specialists. Aims: To construct a population based JEM for chemical agents from data based on a sample of French workers for surveillance purposes. Methods: The SUMEX job-exposure matrix was constructed from data collected via a cross-sectional survey of a sample of French workers representative of the main economic sectors through the SUMER-94 survey: 1205 occupational physicians questioned 48 156 workers, and inventoried exposure to 102 chemicals. The companies' economic activities and the workers' occupations were coded according to the official French nomenclatures. A segmentation method was used to construct job groups that were homogeneous for exposure prevalence to chemical agents. The matrix was constructed in two stages: consolidation of occupations according to exposure prevalence; and establishment of exposure indices based on individual data from all the subjects in the sample. Results: An agent specific matrix could be constructed for 80 of the chemicals. The quality of the classification obtained for each was variable: globally, the performance of the method was better for less specific and therefore more easy to assess agents, and for exposures specific to certain occupations. Conclusions: Software has been developed to enable the SUMEX matrix to be used by occupational physicians and other prevention professionals responsible for surveillance of the health of the workforce in France. PMID:15208374

  5. Human inhalation exposures to toluene, ethylbenzene, and m-xylene and physiologically based pharmacokinetic modeling of exposure biomarkers in exhaled air, blood, and urine.

    PubMed

    Marchand, Axelle; Aranda-Rodriguez, Rocio; Tardif, Robert; Nong, Andy; Haddad, Sami

    2015-04-01

    Urinary biomarkers of exposure are used widely in biomonitoring studies. The commonly used urinary biomarkers for the aromatic solvents toluene (T), ethylbenzene (E), and m-xylene (X) are o-cresol, mandelic acid, and m-methylhippuric acid. The toxicokinetics of these biomarkers following inhalation exposure have yet to be described by physiologically based pharmacokinetic (PBPK) modeling. Five male volunteers were exposed for 6?h in an inhalation chamber to 1/8 or 1/4 of the time-weighted average exposure value (TWAEV) for each solvent: toluene, ethylbenzene, and m-xylene were quantified in blood and exhaled air and their corresponding urine biomarkers were measured in urine. Published PBPK model for parent compounds was used and simulations were compared with experimental blood and exhaled air concentration data. If discrepancies existed, Vmax and Km were optimized. Urinary excretion was modeled using parameters found in literature assuming simply stoichiometric yields from parent compound metabolism and first-order urinary excretion rate. Alternative models were also tested for (1) the possibility that CYP1A2 is the only enzyme implicated in o-cresol and (2) a 2-step model for describing serial metabolic steps for mandelic acid. Models adapted in this study for urinary excretion will be further used to interpret urinary biomarker kinetic data from mixed exposures of these solvents. PMID:25601989

  6. Urinary Lead Exposure and Breast Cancer Risk in a Population-Based Case-Control Study

    PubMed Central

    McElroy, Jane A; Shafer, Martin M; Gangnon, Ronald E; Crouch, Luis A; Newcomb, Polly A

    2015-01-01

    Background Lead is a toxic non-essential metal with widespread exposure starting in utero. Lead has been reclassified in 2004 by the International Agency for Research on Cancer Working Group from a “possible” to “probably” human carcinogen. Lead may be a facilitative or permissive carcinogen which means that lead may permit or augment the genotoxic effects of other exposures. Methods This population-based study in Wisconsin gathered survey data and home-collected urine specimens from 246 women, aged 20–69 years, with incident invasive breast cancer identified from the Wisconsin state registry and 254 age-matched control subjects from population lists from September 2004 to February 2005. We measured urinary lead concentrations by inductively-coupled plasma mass spectrometry, adjusted the values by specific gravity and conducted interviews by telephone to obtain information on known and suspected breast cancer risk factors. Results Women in the highest quartile of specific gravity-adjusted lead level (?1.10 ?g/L) had twice the breast cancer risk of those in the lowest quartile (<0.42 ?g/L; OR = 1.99, 95% CI = 1.1 to 3.6) after adjustment for established risk factors. Excluding women who were currently taking nonsteroidal aromatase inhibitors (n=52), we did not observe any increased breast cancer risk after adjustment for established risk factors. Conclusion Our population-based case-control study suggests that lead exposure, as determined by specific gravity-adjusted urinary lead concentrations, is not associated with a significant increased risk for breast cancer. PMID:18768499

  7. Brain functional network connectivity based on a visual task: visual information processing-related brain regions are significantly activated in the task state

    PubMed Central

    Yang, Yan-li; Deng, Hong-xia; Xing, Gui-yang; Xia, Xiao-luan; Li, Hai-fang

    2015-01-01

    It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we investigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state. Z-values in the vision-related brain regions were calculated, confirming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental findings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception. PMID:25883631

  8. Isotretinoin exposure during pregnancy: a population-based study in The Netherlands

    PubMed Central

    Zomerdijk, Ingeborg M; Ruiter, Rikje; Houweling, Leanne M A; Herings, Ron M C; Sturkenboom, Miriam C J M; Straus, Sabine M J M; Stricker, Bruno H

    2014-01-01

    Objective To estimate isotretinoin exposure in Dutch pregnant women despite the implemented pregnancy prevention programme (PPP) and second, to analyse the occurrence of adverse fetal or neonatal outcomes in these isotretinoin exposed pregnancies. Design Population-based study. Setting The Netherlands. Participants A cohort of 203?962 pregnancies with onset between 1 January 1999 and 1 September 2007 consisting of 208?161 fetuses or neonates. Main outcome measures Isotretinoin exposure in the 30?days before or during pregnancy. Proportions of adverse fetal or neonatal outcomes, defined as intrauterine deaths ?16?week of gestation and neonates with major congenital anomalies. ORs with 95% CIs adjusted for maternal age were calculated to estimate the risk of adverse fetal or neonatal outcome after maternal isotretinoin exposure. Results 51 pregnancies, 2.5 (95% CI 1.9 to 3.3) per 10?000 pregnancies, were exposed to isotretinoin despite the pregnancy prevention programme. Forty-five of these pregnancies, 2.2 (95% CI 1.6 to 2.9) per 10?000 pregnancies, were exposed to isotretinoin during pregnancy and six additional women became pregnant within 30?days after isotretinoin discontinuation. In 60% of isotretinoin exposed pregnancies, women started isotretinoin while already pregnant. In five out of the 51 isotretinoin exposed pregnancies (53 fetuses), 9.4% (95% CI 1.3% to 17.6%), had an adverse fetal or neonatal outcome. The OR for adverse fetal or neonatal outcomes after isotretinoin exposure in 30?days before or during pregnancy was 2.3 (95% CI 0.9 to 5.7) after adjustment for maternal age. Conclusions Although a PPP was already implemented in 1988, we showed that isotretinoin exposed pregnancies and adverse fetal and neonatal events potentially related to the exposure still occur. These findings from the Netherlands add to the evidence that there is no full compliance to the isotretinoin PPP in many Western countries. Given the limited success of iPLEDGE, the question is which further measures are able to improve compliance. PMID:25392022

  9. Disaggregation of nation-wide dynamic population exposure estimates in The Netherlands: Applications of activity-based transport models

    NASA Astrophysics Data System (ADS)

    Beckx, Carolien; Int Panis, Luc; Uljee, Inge; Arentze, Theo; Janssens, Davy; Wets, Geert

    Traditional exposure studies that link concentrations with population data do not always take into account the temporal and spatial variations in both concentrations and population density. In this paper we present an integrated model chain for the determination of nation-wide exposure estimates that incorporates temporally and spatially resolved information about people's location and activities (obtained from an activity-based transport model) and about ambient pollutant concentrations (obtained from a dispersion model). To the best of our knowledge, it is the first time that such an integrated exercise was successfully carried out in a fully operational modus for all models under consideration. The evaluation of population level exposure in The Netherlands to NO 2 at different time-periods, locations, for different subpopulations (gender, socio-economic status) and during different activities (residential, work, transport, shopping) is chosen as a case-study to point out the new features of this methodology. Results demonstrate that, by neglecting people's travel behaviour, total average exposure to NO 2 will be underestimated by 4% and hourly exposure results can be underestimated by more than 30%. A more detailed exposure analysis reveals the intra-day variations in exposure estimates and the presence of large exposure differences between different activities (traffic > work > shopping > home) and between subpopulations (men > women, low socio-economic class > high socio-economic class). This kind of exposure analysis, disaggregated by activities or by subpopulations, per time of day, provides useful insight and information for scientific and policy purposes. It demonstrates that policy measures, aimed at reducing the overall (average) exposure concentration of the population may impact in a different way depending on the time of day or the subgroup considered. From a scientific point of view, this new approach can be used to reduce exposure misclassification.

  10. Raman spectroscopy-based metabolomics for differentiating exposures to triazole fungicides using rat urine.

    PubMed

    Cherney, Daniel P; Ekman, Drew R; Dix, David J; Collette, Timothy W

    2007-10-01

    Normal Raman spectroscopy was evaluated as a metabolomic tool for assessing the impacts of exposure to environmental contaminants, using rat urine collected during the course of a toxicological study. Specifically, one of three triazole fungicides, myclobutanil, propiconazole, or triadimefon, was administered daily via oral gavage to male Sprague-Dawley rats at doses of 300, 300, or 175 mg/kg, respectively. Urine was collected from all three treatment groups and also from vehicle control rats on day six, following five consecutive days of exposure. Spectra were acquired with a CCD-based dispersive Raman spectrometer, using 785-nm diode laser excitation. To optimize the signal-to-noise ratio, urine samples were filtered through a stirred ultrafiltration cell with a 500 nominal molecular weight limit filter to remove large, unwanted urine components that can degrade the spectrum via fluorescence. However, a subsequent investigation suggested that suitable spectra can be obtained in a high-throughput fashion, with little or no Raman-specific sample preparation. For the sake of comparison, a parallel 1H NMR-based metabolomic analysis was also conducted on the unfiltered samples. Results from multivariate data analysis demonstrated that the Raman method compares favorably with NMR in regard to the ability to differentiate responses from these three contaminants. PMID:17718537

  11. Mass Spectrometry-Based Metabolite Profiling in the Mouse Liver following Exposure to Ultraviolet B Radiation

    PubMed Central

    Park, Hye Min; Shon, Jong Cheol; Lee, Mee Youn; Liu, Kwang-Hyeon; Kim, Jeong Kee; Lee, Sang Jun; Lee, Choong Hwan

    2014-01-01

    Although many studies have been performed on the effects of ultraviolet (UV) radiation on the skin, only a limited number of reports have investigated these effects on non-skin tissue. This study aimed to describe the metabolite changes in the liver of hairless mice following chronic exposure to UVB radiation. We did not observe significant macroscopic changes or alterations in hepatic cholesterol and triglyceride levels in the liver of UVB-irradiated mice, compared with those for normal mice. In this study, we detected hepatic metabolite changes by UVB exposure and identified several amino acids, fatty acids, nucleosides, carbohydrates, phospholipids, lysophospholipids, and taurine-conjugated cholic acids as candidate biomarkers in response to UVB radiation in the mouse liver by using various mass spectrometry (MS)-based metabolite profiling including ultra-performance liquid chromatography-quadrupole time-of-flight (TOF)-MS, gas chromatography-TOF-MS and nanomate LTQ-MS. Glutamine exhibited the most dramatic change with a 5-fold increase in quantity. The results from altering several types of metabolites suggest that chronic UVB irradiation may impact significantly on major hepatic metabolism processes, despite the fact that the liver is not directly exposed to UVB radiation. MS-based metabolomic approach for determining regulatory hepatic metabolites following UV irradiation will provide a better understanding of the relationship between internal organs and UV light. PMID:25275468

  12. Changes in Plantar Loading Based on Shoe Type and Sex During a Jump-Landing Task

    PubMed Central

    DeBiasio, Justin C.; Russell, Mary E.; Butler, Robert J.; Nunley, James A.; Queen, Robin M.

    2013-01-01

    Context: Metatarsal stress fractures are common in cleated-sport athletes. Previous authors have shown that plantar loading varies with footwear, sex, and the athletic task. Objective: To examine the effects of shoe type and sex on plantar loading in the medial midfoot (MMF), lateral midfoot (LMF), medial forefoot (MFF), middle forefoot (MidFF), and lateral forefoot (LFF) during a jump-landing task. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Twenty-seven recreational athletes (14 men, 13 women) with no history of lower extremity injury in the last 6 months and no history of foot or ankle surgery. Main Outcome Measure(s): The athletes completed 7 jumping trials while wearing bladed-cleat, turf-cleat, and running shoes. Maximum force, contact area, contact time, and the force-time integral were analyzed in each foot region. We calculated 2 × 3 analyses of variance (? = .05) to identify shoe-condition and sex differences. Results: We found no shoe × sex interactions, but the MMF, LMF, MFF, and LFF force-time integrals were greater in men (P < .03). The MMF maximum force was less with the bladed-cleat shoes (P = .02). Total foot and MidFF maximum force was less with the running shoes (P < .01). The MFF and LFF maximum forces were different among all shoe conditions (P < .01). Total foot contact area was less in the bladed-cleat shoes (P = .01). The MMF contact area was greatest in the running shoes (P < .01). The LFF contact area was less in the running shoes (P = .03). The MFF and LFF force-time integrals were greater with the bladed-cleat shoes (P < .01). The MidFF force-time integral was less in the running shoes (P < .01). Conclusions: Independent of shoe, men and women loaded the foot differently during a jump landing. The bladed cleat increased forefoot loading, which may increase the risk for forefoot injury. The type of shoe should be considered when choosing footwear for athletes returning to activity after metatarsal stress fractures. PMID:24067149

  13. Teaching computer-based spelling to individuals with developmental and hearing disabilities: transfer of stimulus control to writing tasks.

    PubMed Central

    Stromer, R; Mackay, H A; Howell, S R; McVay, A A; Flusser, D

    1996-01-01

    Computer-based instruction may yield widely useful handwritten spelling. Illustrative cases involved individuals with mental retardation and hearing impairments. The participant in Study 1 matched computer pictures and printed words to one another but did not spell the words to pictures. Spelling was then taught using a computerized procedure. In general, increases in the accuracy of computer spelling were accompanied by improvements in written spelling to pictures. Study 2 extended these results with a 2nd participant. After initial training, spelling improved in the context of a retrieval task in which the participant (a) wrote a list of the names of objects displayed on a table, (b) selected the objects from a shelf, and (c) returned the objects to the table. Nearly perfect accuracy scores declined on some retrieval trials conducted without a list, suggesting that the list may have served a mediating function during retrieval. Transfer of stimulus control of computer-based teaching to the retrieval task may have been attributable to the existence of stimulus classes involving pictures, objects, and printed words. Images Figure 1 Figure 3 PMID:8881342

  14. Based on Regular Expression Matching of Evaluation of the Task Performance in WSN: A Queue Theory Approach

    PubMed Central

    Cui, Kai; Zhou, Kuanjiu; Yu, Yanshuo

    2014-01-01

    Due to the limited resources of wireless sensor network, low efficiency of real-time communication scheduling, poor safety defects, and so forth, a queuing performance evaluation approach based on regular expression match is proposed, which is a method that consists of matching preprocessing phase, validation phase, and queuing model of performance evaluation phase. Firstly, the subset of related sequence is generated in preprocessing phase, guiding the validation phase distributed matching. Secondly, in the validation phase, the subset of features clustering, the compressed matching table is more convenient for distributed parallel matching. Finally, based on the queuing model, the sensor networks of task scheduling dynamic performance are evaluated. Experiments show that our approach ensures accurate matching and computational efficiency of more than 70%; it not only effectively detects data packets and access control, but also uses queuing method to determine the parameters of task scheduling in wireless sensor networks. The method for medium scale or large scale distributed wireless node has a good applicability. PMID:25401151

  15. Stomatal ozone fluxes over a barley field in Italy. "Effective exposure" as a possible link between exposure- and flux-based approaches

    NASA Astrophysics Data System (ADS)

    Gerosa, Giacomo; Marzuoli, Riccardo; Cieslik, Stanislaw; Ballarin-Denti, Antonio

    Fluxes of ozone as well as of sensible and latent heat were measured over a barley field in Northern Italy from April to June 2002 with the eddy-correlation technique in order to determine the dose of ozone taken up by plants during the whole grain filling and maturation period. Stomatal ozone fluxes were then calculated by using the similarity between gaseous exchange processes occurring inside the stomata involving ozone and water vapour, whose flux was available from the measurements. The dose was then obtained by integrating the stomatal flux over time. On the average, the stomatal flux was found to be approximately 50% of the total flux. This approach was compared to the currently used ozone risk assessment procedure based on the use of the exposure index AOT40, calculated from routine ozone concentration records. Important differences between these two approaches appeared. In order to assess ozone risk to vegetation in a realistic way, a new concept of "effective exposure", which combines both exposure and uptake approaches, is developed. A new risk assessment index is obtained by weighting exposure by a factor which includes stomatal conductance, obtained by a modelling procedure, which uses observational data available from routine monitoring stations. This new index, formally similar to AOT40, uses a lower ozone concentration threshold (<20 ppb instead of 40 ppb) and follows much more closely the stomatal ozone dose evolution than the original AOT40 index. This approach permits to calculate ozone exposure taking physiological aspects into account, for situations where only ozone concentrations and meteorological observations are available, as direct flux data are difficult to obtain on a routine basis.

  16. Examining pre-service science teachers' developing pedagogical design capacity for planning and supporting task-based classroom discussions

    NASA Astrophysics Data System (ADS)

    Ross, Danielle Kristina

    Teachers face many challenges as we move forward into the age of the Next Generation Science Standards (NGSS) (Achieve, Inc., 2013). The NGSS aim to develop a population of scientifically literate and talented students who can participate in the "innovation-driven economy" (p. 1). In order to meet these goals, teachers must provide students with opportunities to engage in science and engineering practices (SEPs) and learn core ideas of these disciplines. This study followed pre-service secondary science teachers as they participated in a secondary science teacher preparation program intended to support the development of their pedagogical design capacity (Brown, 2009) related to planning and supporting whole-class taskbased discussions. Teacher educators in this program designed an intervention that aimed in supporting this development. This study examined a particular dimension of PDC -- specifically, PSTs effective use of resources to plan science lessons in which students engage in a high demand task, participate in SEPs, and discuss their work in a whole-class setting. In order to examine the effectiveness of the intervention, I had to define PDC a priori. I measured PDC by documenting how/whether PSTs engaged in the following instructional planning practices: developing Learning Goals, selecting and/or designing challenging tasks, anticipating student thinking, planning for monitoring student thinking, imagining the discussion storyline, planning questions, and planning marking strategies. Analyses showed a significant difference between baseline lesson plan scores and Instructional Performance scores. These findings suggest these patterns and changes were directly linked to the teacher preparation program. The mean increase in Instructional Performance scores during the course of the teacher preparation year further supports the effect of the teacher preparation coursework. Pre-service teachers with high pedagogical design capacity continually integrated the ambitious planning practices they learned in their coursework. In contrast, pre-service teachers with low pedagogical design capacity appeared to appropriate the vocabulary and language they learned in coursework, but did not integrate these practices at a high level. This study suggests that pre-service teachers who receive intensive instruction on ambitious planning practices for task-based discussion effectively develop the pedagogical design capacity to plan for task-based discussion lessons.

  17. Systematic review on the health effects of exposure to radiofrequency electromagnetic fields from mobile phone base stations

    PubMed Central

    Frei, Patrizia; Mohler, Evelyn; Hug, Kerstin

    2010-01-01

    Abstract Objective To review and evaluate the recent literature on the health effects of exposure to mobile phone base station (MPBS) radiation. Methods We performed a systematic review of randomized human trials conducted in laboratory settings and of epidemiological studies that investigated the health effects of MPBS radiation in the everyday environment. Findings We included in the analysis 17 articles that met our basic quality criteria: 5 randomized human laboratory trials and 12 epidemiological studies. The majority of the papers (14) examined self-reported non-specific symptoms of ill-health. Most of the randomized trials did not detect any association between MPBS radiation and the development of acute symptoms during or shortly after exposure. The sporadically observed associations did not show a consistent pattern with regard to symptoms or types of exposure. We also found that the more sophisticated the exposure assessment, the less likely it was that an effect would be reported. Studies on health effects other than non-specific symptoms and studies on MPBS exposure in children were scarce. Conclusion The evidence for a missing relationship between MPBS exposure up to 10 volts per metre and acute symptom development can be considered strong because it is based on randomized, blinded human laboratory trials. At present, there is insufficient data to draw firm conclusions about health effects from long-term low-level exposure typically occurring in the everyday environment. PMID:21124713

  18. Closing the research loop: a risk-based approach for communicating results of air pollution exposure studies.

    PubMed Central

    Payne-Sturges, Devon C; Schwab, Margo; Buckley, Timothy J

    2004-01-01

    Communities have long been concerned about the environmental health and environmental quality of their neighborhoods. Community-based exposure assessments have the potential to be an effective way to address these concerns. The success of such studies depends critically on the effective translation and communication of study results back to the study participants and the community. In this article we describe the communication approach applied as part of the South Baltimore Community Exposure Study. Specifically, in conjunction with collecting measurements, we asked the community to define questions they wanted answered and the way in which they wanted to receive study results. To meet their needs, we applied the risk assessment framework. The approach we developed helped residents interpret exposure assessment measurements and gave them the raw materials to effect change in their community. The risk-based approach to presenting participant and community results provides the means to move beyond traditional reporting of concentration values in three important ways. First, risk takes into consideration toxicity, thereby enabling a dialogue about community health concerns. Second, risk provides a common denominator so that exposure and risk can be compared and priorities identified. Third, exposure and risk can be summed, thereby meeting the community's need for information regarding cumulative exposure. This approach may be a useful model for other researchers conducting exposure assessments in response to community concerns. PMID:14698927

  19. Human exposure to mycotoxins and their masked forms through cereal-based foods in Belgium.

    PubMed

    De Boevre, Marthe; Jacxsens, Liesbeth; Lachat, Carl; Eeckhout, Mia; Di Mavungu, José Diana; Audenaert, Kris; Maene, Peter; Haesaert, Geert; Kolsteren, Patrick; De Meulenaer, Bruno; De Saeger, Sarah

    2013-04-26

    In the present study, a quantitative dietary exposure assessment of mycotoxins and their masked forms was conducted on a national representative sample of the Belgian population using the contamination data of cereal-based foods. Cereal-based food products (n=174) were analysed for the occurrence of deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, ?-zearalenol, ?-zearalenol, T-2-toxin, HT-2-toxin, and their respective masked forms, including, deoxynivalenol-3-glucoside, zearalenone-4-glucoside, ?-zearalenol-4-glucoside, ?-zearalenol-4-glucoside and zearalenone-4-sulfate. Fibre-enriched bread, bran-enriched bread, breakfast cereals, popcorn and oatmeal were collected in Belgian supermarkets according to a structured sampling plan and analysed during the period from April 2010 to October 2011. The habitual intake of these food groups was estimated from a national representative food intake survey. According to a probabilistic exposure analysis, the mean (and P95) mycotoxin intake for the sum of the deoxynivalenol-equivalents, zearalenone-equivalents, and the sum of HT-2-and T-2-toxin for all cereal-based foods was 0.1162 (0.4047, P95), 0.0447 (0.1568, P95) and 0.0258 (0.0924, P95) ?g kg(-1)body weight day(-1), respectively. These values were below the tolerable daily intake (TDI) levels for deoxynivalenol, zearalenone and the sum of T-2 and HT-2 toxin (1.0, 0.25 and 0.1 ?g kg(-1)body weight day(-1), respectively). The absolute level exceeding the TDI for all cereal-based foods was calculated, and recorded 0.85%, 2.75% and 4.11% of the Belgian population, respectively. PMID:23454655

  20. Assessing compliance with 60-hertz magnetic-field exposure guidelines.

    PubMed

    Patterson, Robert; Bracken, T; Alldredge, J

    2005-02-01

    Exposure limits for magnetic fields in the extremely low frequency range (3 to 3000 hertz) have been established by a number of organizations. The limits are generally intended to prevent overstimulation of electrically sensitive tissue and are expressed as ceiling values-levels not to be exceeded even momentarily. Exposures near or above the limits occur around high-current equipment and often have large spatial and temporal variability. The combination of variable exposures and ceiling-value exposure limits means that a practical exposure assessment must be statistically based. Practical guidance for assessing compliance for these exposures is limited. To fill this gap, this work develops a statistically based sampling and analysis methodology for evaluating compliance with magnetic-field exposure guidelines, using 60-hertz exposures in the electric utility industry as a model. The resulting methodology relies on (1) defining a scenario that includes tasks with similar high-field exposures for a group of workers, (2) having appropriate protocols for performing magnetic-field personal exposure measurements or having an exposure data set corresponding to that scenario, (3) assuming that the measured peak field is consistent with the exposure limit, (4) assuming that the peak exposure values follow a lognormal distribution, and (5) collecting sufficient measurements to determine the probability of compliance with a desired degree of statistical confidence. As examples, specific compliance probabilities and their confidence intervals are estimated for electric utility scenarios from available personal exposure measurements. This specific application demonstrates the general methodology and indicates that compliance with existing exposure limits may become an issue for certain tasks. PMID:15764528

  1. Pesticide exposure and risk of Parkinson's disease: A family-based case-control study

    PubMed Central

    Hancock, Dana B; Martin, Eden R; Mayhew, Gregory M; Stajich, Jeffrey M; Jewett, Rita; Stacy, Mark A; Scott, Burton L; Vance, Jeffery M; Scott, William K

    2008-01-01

    Background Pesticides and correlated lifestyle factors (e.g., exposure to well-water and farming) are repeatedly reported risk factors for Parkinson's disease (PD), but few family-based studies have examined these relationships. Methods Using 319 cases and 296 relative and other controls, associations of direct pesticide application, well-water consumption, and farming residences/occupations with PD were examined using generalized estimating equations while controlling for age-at-examination, sex, cigarette smoking, and caffeine consumption. Results Overall, individuals with PD were significantly more likely to report direct pesticide application than their unaffected relatives (odds ratio = 1.61; 95% confidence interval, 1.13–2.29). Frequency, duration, and cumulative exposure were also significantly associated with PD in a dose-response pattern (p ? 0.013). Associations of direct pesticide application did not vary by sex but were modified by family history of PD, as significant associations were restricted to individuals with no family history. When classifying pesticides by functional type, both insecticides and herbicides were found to significantly increase risk of PD. Two specific insecticide classes, organochlorines and organophosphorus compounds, were significantly associated with PD. Consuming well-water and living/working on a farm were not associated with PD. Conclusion These data corroborate positive associations of broadly defined pesticide exposure with PD in families, particularly for sporadic PD. These data also implicate a few specific classes of pesticides in PD and thus emphasize the need to consider a more narrow definition of pesticides in future studies. PMID:18373838

  2. Genetic Variation in Base Excision Repair Pathway Genes, Pesticide Exposure, and Prostate Cancer Risk

    PubMed Central

    Koutros, Stella; Berndt, Sonja I.; Andreotti, Gabriella; Hoppin, Jane A.; Sandler, Dale P.; Burdette, Laurie A.; Yeager, Meredith; Freeman, Laura E. Beane; Lubin, Jay H.; Ma, Xiaomei; Zheng, Tongzhang; Alavanja, Michael C.R.

    2011-01-01

    Background: Previous research indicates increased prostate cancer risk for pesticide applicators and pesticide manufacturing workers. Although underlying mechanisms are unknown, evidence suggests a role of oxidative DNA damage. Objectives: Because base excision repair (BER) is the predominant pathway involved in repairing oxidative damage, we evaluated interactions between 39 pesticides and 394 tag single-nucleotide polymorphisms (SNPs) for 31 BER genes among 776 prostate cancer cases and 1,444 male controls in a nested case–control study of white Agricultural Health Study (AHS) pesticide applicators. Methods: We used likelihood ratio tests from logistic regression models to determine p-values for interactions between three-level pesticide exposure variables (none/low/high) and SNPs (assuming a dominant model), and the false discovery rate (FDR) multiple comparison adjustment approach. Results: The interaction between fonofos and rs1983132 in NEIL3 [nei endonuclease VIII-like 3 (Escherichia coli)], which encodes a glycosylase that can initiate BER, was the most significant overall [interaction p-value (pinteract) = 9.3 × 10–6; FDR-adjusted p-value = 0.01]. Fonofos exposure was associated with a monotonic increase in prostate cancer risk among men with CT/TT genotypes for rs1983132 [odds ratios (95% confidence intervals) for low and high use compared with no use were 1.65 (0.91, 3.01) and 3.25 (1.78, 5.92), respectively], whereas fonofos was not associated with prostate cancer risk among men with the CC genotype. Carbofuran and S-ethyl dipropylthiocarbamate (EPTC) interacted similarly with rs1983132; however, these interactions did not meet an FDR < 0.2. Conclusions: Our significant finding regarding fonofos is consistent with previous AHS findings of increased prostate cancer risk with fonofos exposure among those with a family history of prostate cancer. Although requiring replication, our findings suggest a role of BER genetic variation in pesticide-associated prostate cancer risk. PMID:21810555

  3. A physiologically based pharmacokinetic model for developmental exposure to BDE-47 in rats

    SciTech Connect

    Emond, Claude, E-mail: claude.emond@umontreal.c [Departement de sante environnementale et sante au travail Faculte de medecine, Universite de Montreal, P.O. Box 6128, Main Station, Montreal, Quebec, H3C 3J7 (Canada); BioSimulation Consulting Inc., Newark, DE 19711 (United States); Raymer, James H.; Studabaker, William B.; Garner, C. Edwin [RTI International, Research Triangle Park, NC 27709 (United States); Birnbaum, Linda S. [Office of Research and Development, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC 27709 (United States)

    2010-02-01

    Polybrominated diphenyl ethers (PBDEs) are used commercially as additive flame retardants and have been shown to transfer into environmental compartments, where they have the potential to bioaccumulate in wildlife and humans. Of the 209 possible PBDEs, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is usually the dominant congener found in human blood and milk samples. BDE-47 has been shown to have endocrine activity and produce developmental, reproductive, and neurotoxic effects. The objective of this study was to develop a physiologically based pharmacokinetic (PBPK) model for BDE-47 in male and female (pregnant and non-pregnant) adult rats to facilitate investigations of developmental exposure. This model consists of eight compartments: liver, brain, adipose tissue, kidney, placenta, fetus, blood, and the rest of the body. Concentrations of BDE-47 from the literature and from maternal-fetal pharmacokinetic studies conducted at RTI International were used to parameterize and evaluate the model. The results showed that the model simulated BDE-47 tissue concentrations in adult male, maternal, and fetal compartments within the standard deviations of the experimental data. The model's ability to estimate BDE-47 concentrations in the fetus after maternal exposure will be useful to design in utero exposure/effect studies. This PBPK model is the first one designed for any PBDE pharmaco/toxicokinetic description. The next steps will be to expand this model to simulate BDE-47 pharmacokinetics and distributions across species (mice), and then extrapolate it to humans. After mouse and human model development, additional PBDE congeners will be incorporated into the model and simulated as a mixture.

  4. Task\\/Scheduler Logic: Reasoning about Concurrency in Component-Based Systems Software

    Microsoft Academic Search

    Alastair Reid; John Regehr

    2002-01-01

    Although component-based software development promises increased reuse and faster development time, it has proven difficult to build component-based systems software. One obstacle is that the concurrency structure in systems soft- ware tends to be complex. First, instead of a single sched- uler, there is a hierarchy of schedulers: the processor sched- ules interrupts, the OS schedules software interrupts and threads,

  5. Where Is the Mathematics? Examining Teachers' Mathematical Learning Opportunities in Practice-Based Professional Learning Tasks

    ERIC Educational Resources Information Center

    Silver, Edward A.; Clark, Lawrence M.; Ghousseini, Hala N.; Charalambous, Charalambos Y.; Sealy, Jenny T.

    2007-01-01

    Using the work of teaching as a central resource, practice-based approaches to teacher professional development attempt to coordinate and link different facets of teacher knowledge to each other and to the settings in which the knowledge is used. Advocates for practice-based professional development argue that learning experiences that are highly…

  6. Acquisition and Generalization of Chained Tasks Taught with Computer Based Video Instruction to Children with Autism

    ERIC Educational Resources Information Center

    Ayres, Kevin M.; Maguire, Amy; McClimon, Desiree

    2009-01-01

    Three elementary aged students with autism participated in an evaluation of computer based video instruction that targeted functional life skills. The effects of the software were analyzed in the context of a multiple probe design across and replicated across participants. This study represents a departure from more traditional video based

  7. The Multiple Tasks Test

    Microsoft Academic Search

    Bastiaan R Bloem; Vibeke V Valkenburg; Mathilde Slabbekoorn; Mirjam D Willemsen

    2001-01-01

    Simultaneous challenge of posture and cognition (‘dual tasks’) may predict falls better than tests of isolated components of postural control. We describe a new balance test (the Multiple Tasks Test, MTT) which (1) is based upon simultaneous assessment of multiple (>2) postural components; (2) represents everyday situations; and (3) can be applied by clinicians. Relevant risk factors for falls and

  8. Functional Relationships between the Hippocampus and Dorsomedial Striatum in Learning a Visual Scene-Based Memory Task in Rats

    PubMed Central

    Delcasso, Sébastien; Huh, Namjung; Byeon, Jung Seop; Lee, Jihyun; Jung, Min Whan

    2014-01-01

    The hippocampus is important for contextual behavior, and the striatum plays key roles in decision making. When studying the functional relationships with the hippocampus, prior studies have focused mostly on the dorsolateral striatum (DLS), emphasizing the antagonistic relationships between the hippocampus and DLS in spatial versus response learning. By contrast, the functional relationships between the dorsomedial striatum (DMS) and hippocampus are relatively unknown. The current study reports that lesions to both the hippocampus and DMS profoundly impaired performance of rats in a visual scene-based memory task in which the animals were required to make a choice response by using visual scenes displayed in the background. Analysis of simultaneous recordings of local field potentials revealed that the gamma oscillatory power was higher in the DMS, but not in CA1, when the rat performed the task using familiar scenes than novel ones. In addition, the CA1-DMS networks increased coherence at ?, but not at ?, rhythm as the rat mastered the task. At the single-unit level, the neuronal populations in CA1 and DMS showed differential firing patterns when responses were made using familiar visual scenes than novel ones. Such learning-dependent firing patterns were observed earlier in the DMS than in CA1 before the rat made choice responses. The present findings suggest that both the hippocampus and DMS process memory representations for visual scenes in parallel with different time courses and that flexible choice action using background visual scenes requires coordinated operations of the hippocampus and DMS at ? frequencies. PMID:25411483

  9. Touching base: The effect of participant and stimulus modulation factors on a haptic line bisection task.

    PubMed

    Hach, Sylvia; Schütz-Bosbach, Simone

    2012-01-01

    Acquiring information about our environment through touch is vital in everyday life. Yet very little literature exists about factors that may influence haptic or tactile processing. Recent neuroimaging studies have reported haptic laterality effects that parallel those reported in the visual literature. With the use of a haptic variant of the classical line bisection task, the present study aimed to determine the presence of laterality effects on a behavioural level. Specifically, three handedness groups including strong dextrals, strong sinistrals, and-the to-date largely neglected group of-mixed-handers were examined in their ability to accurately bisect stimuli constructed from corrugated board strips of various lengths. Stimulus factors known to play a role in visuospatial perception including stimulus location, the hand used for bisection, and direction of exploration were systematically varied through pseudo-randomisation. Similar to the visual domain, stimulus location and length as well as participants' handedness and the hand used for bisection exerted a significant influence on participants' estimate of the centre of haptically explored stimuli. However, these effects differed qualitatively from those described for the visual domain, and the factor direction of exploration did not exert any significant effect. This indicates that laterality effects reported on a neural level are sufficiently pronounced to result in measurable behavioural effects. The results, first, add to laterality effects reported for the visual and auditory domain, second, are in line with supramodal spatial processing and third, provide additional evidence to a conceptualisation of pseudoneglect and neglect as signs of hemispheric attentional asymmetries. PMID:22385141

  10. Exposure-Response Estimates for Diesel Engine Exhaust and Lung Cancer Mortality Based on Data from Three Occupational Cohorts

    PubMed Central

    Silverman, Debra T.; Garshick, Eric; Vlaanderen, Jelle; Portengen, Lützen; Steenland, Kyle

    2013-01-01

    Background: Diesel engine exhaust (DEE) has recently been classified as a known human carcinogen. Objective: We derived a meta-exposure–response curve (ERC) for DEE and lung cancer mortality and estimated lifetime excess risks (ELRs) of lung cancer mortality based on assumed occupational and environmental exposure scenarios. Methods: We conducted a meta-regression of lung cancer mortality and cumulative exposure to elemental carbon (EC), a proxy measure of DEE, based on relative risk (RR) estimates reported by three large occupational cohort studies (including two studies of workers in the trucking industry and one study of miners). Based on the derived risk function, we calculated ELRs for several lifetime occupational and environmental exposure scenarios and also calculated the fractions of annual lung cancer deaths attributable to DEE. Results: We estimated a lnRR of 0.00098 (95% CI: 0.00055, 0.0014) for lung cancer mortality with each 1-?g/m3-year increase in cumulative EC based on a linear meta-regression model. Corresponding lnRRs for the individual studies ranged from 0.00061 to 0.0012. Estimated numbers of excess lung cancer deaths through 80 years of age for lifetime occupational exposures of 1, 10, and 25 ?g/m3 EC were 17, 200, and 689 per 10,000, respectively. For lifetime environmental exposure to 0.8 ?g/m3 EC, we estimated 21 excess lung cancer deaths per 10,000. Based on broad assumptions regarding past occupational and environmental exposures, we estimated that approximately 6% of annual lung cancer deaths may be due to DEE exposure. Conclusions: Combined data from three U.S. occupational cohort studies suggest that DEE at levels common in the workplace and in outdoor air appear to pose substantial excess lifetime risks of lung cancer, above the usually acceptable limits in the United States and Europe, which are generally set at 1/1,000 and 1/100,000 based on lifetime exposure for the occupational and general population, respectively. Citation: Vermeulen R, Silverman DT, Garshick E, Vlaanderen J, Portengen L, Steenland K. 2014. Exposure-response estimates for diesel engine exhaust and lung cancer mortality based on data from three occupational cohorts. Environ Health Perspect 122:172–177;?http://dx.doi.org/10.1289/ehp.1306880 PMID:24273233

  11. A critical review and analysis of the use of exposure- and flux-based ozone indices for predicting vegetation effects

    NASA Astrophysics Data System (ADS)

    Musselman, Robert C.; Lefohn, Allen S.; Massman, William J.; Heath, Robert L.

    Early studies of plant response to ozone (O 3) utilized concentration-based metrics, primarily by summarizing the commonly monitored hourly average data sets. Research with the O 3 concentration parameter led to the recognition that both peak concentrations and cumulative effects are important when relating plant response to O 3. The US and Canada currently use O 3 concentration-based (exposure-based) parameters for ambient air quality standards for protecting vegetation; the European countries use exposure-based critical levels to relate O 3 to vegetation response. Because plant response is thought to be more closely related to O 3 absorbed into leaf tissue, recent research has been focused on flux-based O 3 parameters. Even though flux-based indices may appear to be more biologically relevant than concentration-based indices, there are limitations associated with their use. The current set of flux-based indices assumes that the plant has no defense mechanism to detoxify O 3. This is a serious limitation. In this paper, we review the literature on exposure- and flux-based indices for predicting plant response. Both exposure- and flux-based metrics may overestimate plant response. At this time, flux-based models that take into consideration detoxification mechanisms (referred to as effective flux) provide the best approach to relate O 3 to plant response. However, because there is considerable uncertainty in quantifying the various defense mechanisms, effective flux at this time is difficult to quantify. Without adequate effective-flux based models, exposure-based O 3 metrics appear to be the only practical measure for use in relating ambient air quality standards to vegetation response.

  12. New Exposure Biomarkers as Tools for Breast Cancer Epidemiology, Biomonitoring, and Prevention: A Systematic Approach Based on Animal Evidence

    PubMed Central

    Ackerman, Janet M.; Attfield, Kathleen R.; Brody, Julia Green

    2014-01-01

    Background: Exposure to chemicals that cause rodent mammary gland tumors is common, but few studies have evaluated potential breast cancer risks of these chemicals in humans. Objective: The goal of this review was to identify and bring together the needed tools to facilitate the measurement of biomarkers of exposure to potential breast carcinogens in breast cancer studies and biomonitoring. Methods: We conducted a structured literature search to identify measurement methods for exposure biomarkers for 102 chemicals that cause rodent mammary tumors. To evaluate concordance, we compared human and animal evidence for agents identified as plausibly linked to breast cancer in major reviews. To facilitate future application of exposure biomarkers, we compiled information about relevant cohort studies. Results: Exposure biomarkers have been developed for nearly three-quarters of these rodent mammary carcinogens. Analytical methods have been published for 73 of the chemicals. Some of the remaining chemicals could be measured using modified versions of existing methods for related chemicals. In humans, biomarkers of exposure have been measured for 62 chemicals, and for 45 in a nonoccupationally exposed population. The Centers for Disease Control and Prevention has measured 23 in the U.S. population. Seventy-five of the rodent mammary carcinogens fall into 17 groups, based on exposure potential, carcinogenicity, and structural similarity. Carcinogenicity in humans and rodents is generally consistent, although comparisons are limited because few agents have been studied in humans. We identified 44 cohort studies, with a total of > 3.5 million women enrolled, that have recorded breast cancer incidence and stored biological samples. Conclusions: Exposure measurement methods and cohort study resources are available to expand biomonitoring and epidemiology related to breast cancer etiology and prevention. Citation: Rudel RA, Ackerman JM, Attfield KR, Brody JG. 2014. New exposure biomarkers as tools for breast cancer epidemiology, biomonitoring, and prevention: a systematic approach based on animal evidence. Environ Health Perspect 122:881–895;?http://dx.doi.org/10.1289/ehp.1307455 PMID:24818537

  13. Late Pleistocene and Holocene Beringia vegetation dynamic reconstructions based on a yedoma exposure, Itkillik (Alaska)

    NASA Astrophysics Data System (ADS)

    Lapointe Elmrabti, L.; Fortier, D.; Shur, Y.; Kanevskiy, M. Z.; Talbot, J.

    2013-12-01

    The Itkillik river area in Alaska (69°34? N, 150°52?W), is part of the loosely defined region of Beringia, which was largely unglaciated during the last ice age. Beringia is known to have acted as a refugium for boreal trees and shrubs during the Pleistocene, but questions remain about the environmental history of North-Eastern Beringia, especially the extent and dynamics of the now extinct tundra-steppe biome. The 33-m-high Itkillik river exposure formed over the late Pleistocene / early Holocene (48,000 to 5,000 14C yr BP) and the exposed eolian sediments are largely undisturbed, offering a unique opportunity to examine a long term vegetation sequence in high latitude environment and link the vegetation reconstructions with the sedimentology and cryostratigraphy of the region. Because of the very low concentration of pollen in the sediments, we utilized an extraction method based on heavy-liquid (Sodium Polytungstate (SPT)) separation. Our results show a tundra-steppe vegetation type, characterized by the abundance of cyperacea and graminea taxa. Overall the pollen record of the Itkillik exposure will provide an important point of comparison to other sites localised in the circumpolar circle, especially in Siberia, as yedoma remains one of the most noticeable structures of the cold and dry periglacial environment of the Arctic and subarctic east Siberia. Implications of our findings for local climate reconstructions using pollen-climate transfer functions are discussed.

  14. Radiation exposure in X-ray-based imaging techniques used in osteoporosis

    PubMed Central

    Adams, Judith E.; Guglielmi, Giuseppe; Link, Thomas M.

    2010-01-01

    Recent advances in medical X-ray imaging have enabled the development of new techniques capable of assessing not only bone quantity but also structure. This article provides (a) a brief review of the current X-ray methods used for quantitative assessment of the skeleton, (b) data on the levels of radiation exposure associated with these methods and (c) information about radiation safety issues. Radiation doses associated with dual-energy X-ray absorptiometry are very low. However, as with any X-ray imaging technique, each particular examination must always be clinically justified. When an examination is justified, the emphasis must be on dose optimisation of imaging protocols. Dose optimisation is more important for paediatric examinations because children are more vulnerable to radiation than adults. Methods based on multi-detector CT (MDCT) are associated with higher radiation doses. New 3D volumetric hip and spine quantitative computed tomography (QCT) techniques and high-resolution MDCT for evaluation of bone structure deliver doses to patients from 1 to 3 mSv. Low-dose protocols are needed to reduce radiation exposure from these methods and minimise associated health risks. PMID:20559834

  15. Effect of exposure in steam or argon on the creep properties of Ni-based alloys

    SciTech Connect

    Dryepondt, Sebastien N [ORNL; Unocic, Kinga A [ORNL; Pint, Bruce A [ORNL

    2012-01-01

    Although expensive, Ni-based superalloys are of interest for the ultrasupercritical steam program because of their good creep and oxidation resistance at temperature above 700 C. However, the effect of steam oxidation on the alloy mechanical properties is unknown, and creep specimens of alloy CCA617, 740 and 230 were pre-oxidized for 2000 and 4000h in steam at 800 C before testing in air at the same temperature. Exposure in steam decreased the creep properties of alloy CCA617 compared with as fabricated material, had less of an effect on alloy 740, and did not affect alloy 230. Testing of a specimen repolished after steam exposure as well as microstructure observation indicate that the oxidation affected zone at the specimen surface is not responsible for the properties degradation. Surprisingly, a similar time anneal in an inert environment resulted in a drastic decrease of creep rupture life and an increase in the creep rate and elongation at rupture. TEM analysis revealed that the mechanical properties decrease for alloy CCA617 is related to the absence of precipitates in the grain.

  16. Non parametric denoising methods based on wavelets: Application to electron microscopy images in low exposure time

    NASA Astrophysics Data System (ADS)

    Soumia, Sid Ahmed; Messali, Zoubeida; Ouahabi, Abdeldjalil; Trepout, Sylvain; Messaoudi, Cedric; Marco, Sergio

    2015-01-01

    The 3D reconstruction of the Cryo-Transmission Electron Microscopy (Cryo-TEM) and Energy Filtering TEM images (EFTEM) hampered by the noisy nature of these images, so that their alignment becomes so difficult. This noise refers to the collision between the frozen hydrated biological samples and the electrons beam, where the specimen is exposed to the radiation with a high exposure time. This sensitivity to the electrons beam led specialists to obtain the specimen projection images at very low exposure time, which resulting the emergence of a new problem, an extremely low signal-to-noise ratio (SNR). This paper investigates the problem of TEM images denoising when they are acquired at very low exposure time. So, our main objective is to enhance the quality of TEM images to improve the alignment process which will in turn improve the three dimensional tomography reconstructions. We have done multiple tests on special TEM images acquired at different exposure time 0.5s, 0.2s, 0.1s and 1s (i.e. with different values of SNR)) and equipped by Golding beads for helping us in the assessment step. We herein, propose a structure to combine multiple noisy copies of the TEM images. The structure is based on four different denoising methods, to combine the multiple noisy TEM images copies. Namely, the four different methods are Soft, the Hard as Wavelet-Thresholding methods, Bilateral Filter as a non-linear technique able to maintain the edges neatly, and the Bayesian approach in the wavelet domain, in which context modeling is used to estimate the parameter for each coefficient. To ensure getting a high signal-to-noise ratio, we have guaranteed that we are using the appropriate wavelet family at the appropriate level. So we have chosen â?IJsym8â?? wavelet at level 3 as the most appropriate parameter. Whereas, for the bilateral filtering many tests are done in order to determine the proper filter parameters represented by the size of the filter, the range parameter and the spatial parameter respectively. The experiments reported in this paper demonstrate the performance of the Bilateral Filtering and the Bayesian approaches in terms of improving the SNRout and the image quality. Taken together, these results suggest that the Bayesian process has a potential to outperform all the used methods, where in the multiple noisy copies structure it gave us the best SNRout without change of the golden beads diameter. The Bayesian approach yielded enhanced average image without needing a huge amount of copies.

  17. A Case-Based Approach to Managing Geo-spatial Imagery Tasks

    Microsoft Academic Search

    Dympna O’Sullivan; Eoin Mcloughlin; Michela Bertolotto; David C. Wilson

    2004-01-01

    Advances in technology for digital image capture and storage have caused an information overload problem in the geo-sciences. This has compounded existing image retrieval problems whereby most image matching is performed using content-based image retrieval techniques. The biggest problem in this field is the so-called semantic gap – the mismatch between the capabilities of current content-based image retrieval systems and

  18. A task-oriented agent-based mechanism for mathematical assistant systems

    Microsoft Academic Search

    Quoc Bao Vo

    2004-01-01

    We present an agent-based mechanism that acts as a mediator module between theorem proving sys- tems and mathematical knowledge bases containing information that is necessary for the constructions of proofs. Unlike the more popular user-oriented mediators who work as information agents to provide the so-called value-added services to the collected data before presenting it to users or user applications, our

  19. Elementary Students’ Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks

    Microsoft Academic Search

    Kristen Bethke Wendell; Hee-Sun Lee

    2010-01-01

    Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline\\u000a within the study of matter. This paper examines how third grade students’ materials science performance changes over the course\\u000a of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering\\u000a design-based science instruction with the

  20. Effect of training on exposure judgment accuracy of industrial hygienists.

    PubMed

    Vadali, Monika; Ramachandran, Gurumurthy; Mulhausen, John R; Banerjee, Sudipto

    2012-01-01

    Results are presented from a study that investigated the effect of data interpretation training on exposure judgment accuracy of industrial hygienists across several companies in different industry sectors. Participating companies provided monitoring information on specific exposure tasks. Forty-nine hygienists from six companies participated in the study, and 22 industrial tasks were evaluated. The number of monitoring data points for individual tasks varied between 5 and 24. After reviewing all available basic characterization information for the job, task, and chemical, hygienists were asked to provide their judgment on the probability of the 95th percentile of the underlying exposure distribution being located in one of four exposure categories relative to the occupational exposure limit as outlined in the AIHA exposure assessment strategy. Ninety-three qualitative judgments (i.e., without reviewing monitoring data) and 2142 quantitative judgments (i.e., those made after reviewing monitoring data) were obtained. Data interpretation training, with simple rules of thumb for estimating 95th percentiles, was provided to all hygienists. A data interpretation test was administered before and after training. All exposure task judgments were collected before and after training. Data interpretation test accuracy for the hygienists increased from 48% to 67% after training (p < 0.001) and a significant underestimation bias was removed. Hygienist quantitative task judgment accuracy improved from 46% to 69% (p < 0.001) post-training. Accuracy results showed good improvement in industrial hygienists' quantitative judgments as a result of training. Hence, the use of statistical tools is promoted to improve judgments based on monitoring data and provide feedback and calibration to improve qualitative judgments. It may be worthwhile to develop standard training programs to improve exposure judgments. PMID:22463121

  1. A COMMUNITY-BASED CHILDREN'S PESTICIDE EXPOSURE MEASUREMENT STUDY IN JACKSONVILLE, FLORIDA

    EPA Science Inventory

    Children's exposures to pesticides and chemicals in consumer products may be different, and in some cases, higher than exposures for adults. The U.S. Environmental Protection Agency (EPA) is conducting research to gain a better understanding of children's exposures and the fac...

  2. Task Description Language

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

  3. Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

    NASA Technical Reports Server (NTRS)

    Looney, Alan

    1991-01-01

    Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

  4. Analysing Task Design and Students' Responses to Context-Based Problems through Different Analytical Frameworks

    ERIC Educational Resources Information Center

    Broman, Karolina; Bernholt, Sascha; Parchmann, Ilka

    2015-01-01

    Background: Context-based learning approaches are used to enhance students' interest in, and knowledge about, science. According to different empirical studies, students' interest is improved by applying these more non-conventional approaches, while effects on learning outcomes are less coherent. Hence, further insights are needed into the…

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

    Microsoft Academic Search

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

    2011-01-01

    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

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

    Microsoft Academic Search

    Tim Flohrer; Holger Krag; Heiner Klinkrad; Thomas Schildknecht

    2010-01-01

    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 instrumentation was to analyse how the

  7. Elementary Students' Learning of Materials Science Practices through Instruction Based on Engineering Design Tasks

    ERIC Educational Resources Information Center

    Wendell, Kristen Bethke; Lee, Hee-Sun

    2010-01-01

    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…

  8. The Effects of Task, Database, and Guidance on Interaction in a Goal-Based Scenario.

    ERIC Educational Resources Information Center

    Bell, Benjamin

    This paper describes the "Sickle Cell Counselor" (SCC), a goal based scenario on permanent display at the Museum of Science and Industry in Chicago. SCC is an exploratory hypermedia simulation program which provides users with a basic understanding of Sickle Cell Anemia. The user of the program plays the role of a genetic counselor, and, while…

  9. Laboratory-Based and Autobiographical Retrieval Tasks Differ Substantially in Their Neural Substrates

    ERIC Educational Resources Information Center

    McDermott, Kathleen B.; Szpunar, Karl K.; Christ, Shawn E.

    2009-01-01

    In designing experiments to investigate retrieval of event memory, researchers choose between utilizing laboratory-based methods (in which to-be-remembered materials are presented to participants) and autobiographical approaches (in which the to-be-remembered materials are events from the participant's pre-experimental life). In practice, most…

  10. Language identification techniques based on full recognition in an air traffic control task

    Microsoft Academic Search

    Ricardo de Córdoba; Javier Ferreiros; Valentín Sama; Javier Macías Guarasa; Luis Fernando D'Haro; Fernando Fernandez

    2004-01-01

    Automatic language identification has become an important issue in recent years in speech recognition systems. In this paper, we present the work done in language identification for an air traffic control speech recognizer for continuous speech. The system is able to distinguish between Spanish and English. We present several language identification techniques based on full recognition that improve the baseline

  11. The Relationship between Shared Mental Models and Task Performance in an Online Team- Based Learning Environment

    ERIC Educational Resources Information Center

    Johnson, Tristan E.; Lee, Youngmin

    2008-01-01

    In an effort to better understand learning teams, this study examines the effects of shared mental models on team and individual performance. The results indicate that each team's shared mental model changed significantly over the time that subjects participated in team-based learning activities. The results also showed that the shared mental…

  12. Spectral Template Based Classification of Robotic Whisker Sensor Signals in a Floor Texture Discrimination Task.

    E-print Network

    Barker, Jon

    or cloudy environments, and is covert (i.e. does not emit light or sound). Whisker sensors are mechanicallySpectral Template Based Classification of Robotic Whisker Sensor Signals in a Floor Texture while the robot moved in different directions on four different real-world floor surfaces: rough

  13. Task-Based Navigation of a Taxonomy Interface to a Digital Repository

    ERIC Educational Resources Information Center

    Khoo, Christopher S. G.; Wang, Zhonghong; Chaudhry, Abdus Sattar

    2012-01-01

    Introduction: This is a study of hierarchical navigation; how users browse a taxonomy-based interface to an organizational repository to locate information resources. The study is part of a project to develop a taxonomy for an library and information science department to organize resources and support user browsing in a digital repository.…

  14. Capture, Storage and Reuse of Lessons about Information Resources: Supporting Task-Based Information Search

    E-print Network

    Leake, David B.

    -Based Information Search David B. Leake, Travis Bauer, Ana Maguitman and David C. Wilson Computer Science Department Livingston and John Melton at NASA Ames Research Center, and of Alberto Ca~nas and the Concept Mapping group- ferent courses of action, generating feasibility studies, generating or re ning designs, etc.

  15. Whether Skill Acquisition is Rule or Instance Based is determined by the Structure of the Task

    Microsoft Academic Search

    Niels A. Taatgen; Dieter Wallach

    2002-01-01

    The traditional view of skill acquisition is that it can be explained by a gradual transition from behavior based on declarative rules in the form of examples or instructions towards general knowledge represented by procedural rules. This view is challenged by Logan's instance theory, which specifies that skill acquisition can be explained by the accumula- tion of examples or instances

  16. Model-based learning with Bayesian and MAXQ value function decomposition for hierarchical task

    Microsoft Academic Search

    Zhaohui Dai; Xin Chen; Weihua Cao; Min Wu

    2010-01-01

    How to improve efficiency of learning is always the key issue for implementation of reinforcement learning. This paper makes use of advantages of both hierarchical learning and model-based learning, so that an improved algorithm, named Bayesian-MAXQ learning, is introduced, in which several modifications are developed to solve the value update of hierarchy, while the possible performance damages brought by prioritized

  17. Description of a Nanobody-based Competitive Immunoassay to Detect Tsetse Fly Exposure

    PubMed Central

    Caljon, Guy; Hussain, Shahid; Vermeiren, Lieve; Van Den Abbeele, Jan

    2015-01-01

    Background Tsetse flies are the main vectors of human and animal African trypanosomes. The Tsal proteins in tsetse fly saliva were previously identified as suitable biomarkers of bite exposure. A new competitive assay was conceived based on nanobody (Nb) technology to ameliorate the detection of anti-Tsal antibodies in mammalian hosts. Methodology/Principal Findings A camelid-derived Nb library was generated against the Glossina morsitans morsitans sialome and exploited to select Tsal specific Nbs. One of the three identified Nb families (family III, TsalNb-05 and TsalNb-11) was found suitable for anti-Tsal antibody detection in a competitive ELISA format. The competitive ELISA was able to detect exposure to a broad range of tsetse species (G. morsitans morsitans, G. pallidipes, G. palpalis gambiensis and G. fuscipes) and did not cross-react with the other hematophagous insects (Stomoxys calcitrans and Tabanus yao). Using a collection of plasmas from tsetse-exposed pigs, the new test characteristics were compared with those of the previously described G. m. moristans and rTsal1 indirect ELISAs, revealing equally good specificities (> 95%) and positive predictive values (> 98%) but higher negative predictive values and hence increased sensitivity (> 95%) and accuracy (> 95%). Conclusion/Significance We have developed a highly accurate Nb-based competitive immunoassay to detect specific anti-Tsal antibodies induced by various tsetse fly species in a range of hosts. We propose that this competitive assay provides a simple serological indicator of tsetse fly presence without the requirement of test adaptation to the vertebrate host species. In addition, the use of monoclonal Nbs for antibody detection is innovative and could be applied to other tsetse fly salivary biomarkers in order to achieve a multi-target immunoprofiling of hosts. In addition, this approach could be broadened to other pathogenic organisms for which accurate serological diagnosis remains a bottleneck. PMID:25658871

  18. Variable sensitivity in unsupervised clustering tasks with an n-tuple-based self-organising neural network.

    PubMed

    Tambouratzis, G

    2000-04-01

    This article investigates the application of the SOLNN (Self-Organising Logic Neural Network) n-tuple-based network to character recognition and image segmentation clustering tasks, where the classes consist of a large number of distinct sub-classes. It is shown that the SOLNN clustering performance and node utilisation are both improved by virtue of the distribution constraint mechanism. The clustering results are supported by means of a detailed analysis of the characteristics of each pattern space. This analysis, coupled with comparative results obtained using other self-organising models, illustrates that the SOLNN clusters the patterns in accordance to the pattern space characteristics and thus is well-suited to clustering complex datasets. PMID:10939344

  19. Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering.

    PubMed

    Suraj; Tiwari, Purnendu; Ghosh, Subhojit; Sinha, Rakesh Kumar

    2015-01-01

    Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means clustering is found to outperform genetic algorithm (GA) and particle swarm optimization (PSO) based K-means clustering techniques in terms of both accuracy and execution time. The lesser execution time of hybrid GA-PSO technique makes it suitable for real time BCI application. Time frequency representation (TFR) techniques have been used to extract the feature of the signal under investigation. TFRs based features are extracted and relying on the concept of event related synchronization (ERD) and desynchronization (ERD) feature vector is formed. PMID:25972896

  20. Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering

    PubMed Central

    Suraj; Tiwari, Purnendu; Ghosh, Subhojit; Sinha, Rakesh Kumar

    2015-01-01

    Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means clustering is found to outperform genetic algorithm (GA) and particle swarm optimization (PSO) based K-means clustering techniques in terms of both accuracy and execution time. The lesser execution time of hybrid GA-PSO technique makes it suitable for real time BCI application. Time frequency representation (TFR) techniques have been used to extract the feature of the signal under investigation. TFRs based features are extracted and relying on the concept of event related synchronization (ERD) and desynchronization (ERD) feature vector is formed. PMID:25972896

  1. Multiple learning modes in the development of performance on a rule-based category-learning task.

    PubMed

    Schmittmann, Verena D; Visser, Ingmar; Raijmakers, Maartje E J

    2006-01-01

    Behavioral and neuropsychological data suggest that multiple systems are involved in category-learning. In this paper, the existence and the development of multiple modes of learning of a rule-based category structure was examined, and features of different learning processes were identified. Data were obtained in a cross-sectional study by Raijmakers et al. [Raijmakers, M. E. J., Dolan, C. V., & Molenaar, P. C. M. (2001). Finite mixture distribution models of simple discrimination learning. Memory and Cognition, 29, 659-677], in which subjects aged 4-20 years carried out a rule-based category-learning task. Learning models were employed to investigate the development of the learning processes in the sample. The results support the hypothesis of two distinct learning modes, rather than a single general mode of learning with a continuum of appearances. One mode represents sudden rational learning by means of hypothesis testing. In the second, slow learning mode, learning also occurs suddenly as opposed to incrementally. The probability of rational learning increases with age, and seems to be related to dimension preference in the younger age groups. However, the finding of distinct learning modes does not necessarily imply that distinct learning systems are involved. Implications for the interpretation and clinical use of tasks with a category-learning component, such as the Wisconsin Card Sorting Test (WCST [Heaton, R. K., Chelune, G. J., Talley, J. L., Kay, G. G., & Curtis, G. (Eds.). (1993). Wisconsin card sorting test manual: Revised and expanded. Odessa, FL: Psychological Assessment Resources]), are discussed. PMID:16481013

  2. TeamWorker: An Agent-Based Support System for Mobile Task Execution

    Microsoft Academic Search

    Habin Lee; Patrik Mihailescu; John Shepherdson

    An organization’s mobile workforce is a vital asset, as it is in the front line liaising with customers, and driving the sale of an organization’s products and\\/or services. Despite this, the IT support provided to mobile workers is often inferior to that available to office-based workers. Mobile workers operate in an unreliable environment, and as such require differing types of

  3. Implementation and operation of VAX-based data acquisition system for the large coil task

    SciTech Connect

    Baylor, L.R.; Blair, E.T.; Greenwood, D.E.; Munro, J.K.

    1985-01-01

    The VAX-based data acquisition system for the International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL) is a second generation system that evolved from a PDP-11/60-based system used in the two-coil test and facility shakedown. The VAX 11/780 processor has been interfaced through a CAMAC fiber-optic byte serial highway to five existing LSI-11/23 frontend processors through dataway access port (DAP) modules. The VAX CAMAC interface has permitted the addition of analog input channels for the refrigeration system and analog and digital outputs to drive display devices. Software utilities are provided to operate the data acquisition hardware, maintain data base files, and display data. Graphical display of data is accomplished through the use of VAX IDL (Interactive Data Language), which provides device-independent data presentation. Output from IDL is available for Tektronix displays and has been extended to generate TKF and Versaplot graphics metafiles for hardcopy output to Versatec printer/plotters. In addition, a Sension display system is available for graphical display of real-time data in the form of strip chart and tabular displays. This paper describes the hardware and software design of the system and the operation of the system during the full-array testing sequence.

  4. Interest contagion in violation-of-expectation-based false-belief tasks

    PubMed Central

    Falck, Andreas; Brinck, Ingar; Lindgren, Magnus

    2014-01-01

    In the debate about how to interpret Violation-of-Expectation (VoE) based false-belief experiments, it has been suggested that infants are predicting the actions of the agent based on more or less sophisticated cognitive means. We present an alternative, more parsimonious interpretation, exploring the possibility that the infants’ reactions are not governed by rational expectation but rather of memory strength due to differences in the allocation of cognitive resources earlier in the experiment. Specifically, it is argued that (1) infants’ have a tendency to find more interest in events that observed agents are attending to as opposed to unattended events (“interest contagion”), (2) the object-location configurations that result from such interesting events are remembered more strongly by the infants, and (3) the VoE contrast arises as a consequence of the difference in memory strength between more and less interesting object-location configurations. We discuss two published experiments, one which we argue that our model can explain (Kovács etal., 2010), and one which we argue cannot be readily explained by our model (Onishi and Baillargeon, 2005). PMID:24523706

  5. Does Digital Game-Based Learning Improve Student Time-on-Task Behavior and Engagement in Comparison to Alternative Instructional Strategies?

    ERIC Educational Resources Information Center

    Schaaf, Ryan

    2012-01-01

    Digital Game-Based Learning (DGBL) activities were examined in comparison with effective, research-based learning strategies to observe any difference in student engagement and time-on task behavior. Experimental and control groups were randomly selected amongst the intermediate elementary school students ages 8 to 10 years old. Student…

  6. Simulation tests to assess occupational exposure to airborne asbestos from asphalt-based roofing products.

    PubMed

    Mowat, Fionna; Weidling, Ryan; Sheehan, Patrick

    2007-07-01

    This study sought to evaluate exposure from specific products to evaluate potential risk from roof repair activities. Five asbestos-containing fibered roof coatings and plastic cements, representing a broad range of these types of products, were tested in exposure simulations. These products were applied to representative roof substrates. Release of asbestos fibers during application and sanding of the product shortly thereafter (wet sanding) were tested initially. Other roof substrates were cured to simulate a product that had been on a rooftop for several months and then were tested to evaluate release of fibers during hand sanding and hand scraping activities. Additional tests were also conducted to evaluate asbestos release during product removal from tools and clothing. Two personal (n = 84) and background/clearance (n = 49) samples were collected during each 30-min test and analyzed for total fiber concentration [phase-contrast microscopy (PCM)] and for asbestos fiber count [transmission electron microscopy (TEM)]. PCM concentrations ranged from <0.005 to 0.032 fibers per cubic centimeter (f cc(-1)). Chrysotile fibers were detected in 28 of 84 personal samples collected. TEM concentrations ranged from <0.0021 to 0.056 f cc(-1). Calculated 8-h time-weighted averages (TWAs) ranged from 0.0003 to 0.002 f cc(-1) and were comparable to the background TWA concentration of 0.0002 f cc(-1) measured in this study. Based on these results, it is unlikely that roofers were exposed to airborne asbestos concentrations above the current or historical occupational guidelines during scraping and sanding of these products during roof repair. PMID:17761688

  7. Global assessment of exposure to faecal contamination through drinking water based on a systematic review

    PubMed Central

    Bain, Robert; Cronk, Ryan; Hossain, Rifat; Bonjour, Sophie; Onda, Kyle; Wright, Jim; Yang, Hong; Slaymaker, Tom; Hunter, Paul; Prüss-Ustün, Annette; Bartram, Jamie

    2014-01-01

    Objectives To estimate exposure to faecal contamination through drinking water as indicated by levels of Escherichia coli (E. coli) or thermotolerant coliform (TTC) in water sources. Methods We estimated coverage of different types of drinking water source based on household surveys and censuses using multilevel modelling. Coverage data were combined with water quality studies that assessed E. coli or TTC including those identified by a systematic review (n = 345). Predictive models for the presence and level of contamination of drinking water sources were developed using random effects logistic regression and selected covariates. We assessed sensitivity of estimated exposure to study quality, indicator bacteria and separately considered nationally randomised surveys. Results We estimate that 1.8 billion people globally use a source of drinking water which suffers from faecal contamination, of these 1.1 billion drink water that is of at least ‘moderate’ risk (>10 E. coli or TTC per 100 ml). Data from nationally randomised studies suggest that 10% of improved sources may be ‘high’ risk, containing at least 100 E. coli or TTC per 100 ml. Drinking water is found to be more often contaminated in rural areas (41%, CI: 31%–51%) than in urban areas (12%, CI: 8–18%), and contamination is most prevalent in Africa (53%, CI: 42%–63%) and South-East Asia (35%, CI: 24%–45%). Estimates were not sensitive to the exclusion of low quality studies or restriction to studies reporting E. coli. Conclusions Microbial contamination is widespread and affects all water source types, including piped supplies. Global burden of disease estimates may have substantially understated the disease burden associated with inadequate water services. PMID:24811893

  8. Responses of Lyngbya wollei to exposures of copper-based algaecides: the critical burden concept.

    PubMed

    Bishop, W M; Rodgers, J H

    2012-04-01

    The formulation of a specific algaecide can greatly influence the bioavailability, uptake, and consequent control of the targeted alga. In this research, three copper-based algaecide formulations were evaluated in terms of copper sorption to a specific problematic alga and amount of copper required to achieve control. The objectives of this study were (1) to compare the masses of copper required to achieve control of Lyngbya wollei using the algaecide formulations Algimycin-PWF, Clearigate, and copper sulfate pentahydrate in laboratory toxicity experiments; (2) to relate the responses of L. wollei to the masses of copper adsorbed and absorbed (i.e., dose) as well as the concentrations of copper in the exposure water; and (3) to discern the relation between the mass of copper required to achieve control of a certain mass of L. wollei among different algaecide formulations. The critical burden of copper (i.e., threshold algaecide concentration that must be absorbed or adsorbed to achieve control) for L. wollei averaged 3.3 and 1.9 mg Cu/g algae for Algimycin-PWF and Clearigate, respectively, in experiments with a series of aqueous copper concentrations, water volumes, and masses of algae. With reasonable exposures in these experiments, control was not achieved with single applications of copper sulfate despite copper sorption >13 mg Cu/g algae in one experiment. Factors governing the critical burden of copper required for control of problematic cyanobacteria include algaecide formulation and concentration, volume of water, and mass of algae. By measuring the critical burden of copper from an algaecide formulation necessary to achieve control of the targeted algae, selection of an effective product and treatment rate can be calculated at a given field site. PMID:21968539

  9. The Effect of Long-Term Thermal Exposure at Elevated Temperatures on Microstructures and Mechanical Properties in Centrifugally Casted Iron-Base Alloy

    Microsoft Academic Search

    Gobboon LOTHONGKUM

    This work has an aim to study and investigate the relationship between high temperature exposure conditions on microstructural evolution and mechanical properties in the iron-based alloy, Fe-30.8 Ni - 26.6 Cr alloy, strengthened by carbide precipitation. Two exposure temperatures (900 and 1000°C) with various thermal exposure times are introduced to the as-received alloy. After short-term exposure, it was found that

  10. Data Collection issues: Measurement of multi-pollutant and multi-pathway exposures in a probability-based sample of children: practical strategies for effective field studies

    Microsoft Academic Search

    JOHN L ADGATE; C ANDREW CLAYTON; JAMES J QUACKENBOSS; KENT W THOMAS; ROY W WHITMORE; EDO D PELLIZZARI; PAUL J LIOY; PAMELA SHUBAT; CHUCK STROEBEL; NATALIE C G FREEMAN; KEN SEXTON

    2000-01-01

    The purpose of this manuscript is to describe the practical strategies developed for the implementation of the Minnesota Children's Pesticide Exposure Study (MNCPES), which is one of the first probability-based samples of multi-pathway and multi-pesticide exposures in children. The primary objective of MNCPES was to characterize children's exposure to selected pesticides through a combination of questionnaires, personal exposure measurements (i.e.,

  11. Preoperative Mapping of the Sensorimotor Cortex: Comparative Assessment of Task-Based and Resting-State fMRI

    PubMed Central

    Rosazza, Cristina; Aquino, Domenico; D’Incerti, Ludovico; Cordella, Roberto; Andronache, Adrian; Zacà, Domenico; Bruzzone, Maria Grazia; Tringali, Giovanni; Minati, Ludovico

    2014-01-01

    Resting state fMRI (rs-fMRI) has recently been considered as a possible complement or alternative to task-based fMRI (tb-fMRI) for presurgical mapping. However, evidence of its usefulness remains scant, because existing studies have investigated relatively small samples and focused primarily on qualitative evaluation. The aim of this study is to investigate the clinical usefulness of rs-fMRI in the context of presurgical mapping of motor functions, and in particular to determine the degree of correspondence with tb-fMRI which, while not a gold-standard, is commonly used in preoperative setting. A group of 13 patients with lesions close to the sensorimotor cortex underwent rs-fMRI and tb-fMRI to localize the hand, foot and mouth motor areas. We assessed quantitatively the degree of correspondence between multiple rs-fMRI analyses (independent-component and seed-based analyses) and tb-fMRI, with reference to sensitivity and specificity of rs-fMRI with respect to tb-fMRI, and centre-of-mass distances. Agreement with electro-cortical stimulation (ECS) was also investigated, and a traditional map thresholding approach based on agreement between two experienced operators was compared to an automatic threshold determination method. Rs-fMRI can localize the sensorimotor cortex successfully, providing anatomical specificity for hand, foot and mouth motor subregions, in particular with seed-based analyses. Agreement with tb-fMRI was only partial and rs-fMRI tended to provide larger patterns of correlated activity. With respect to the ECS data available, rs-fMRI and tb-fMRI performed comparably, even though the shortest distance to stimulation points was observed for the latter. Notably, the results of both were on the whole robust to thresholding procedure. Localization performed by rs-fMRI is not equivalent to tb-fMRI, hence rs-fMRI cannot be considered as an outright replacement for tb-fMRI. Nevertheless, since there is significant agreement between the two techniques, rs-fMRI can be considered with caution as a potential alternative to tb-fMRI when patients are unable to perform the task. PMID:24914775

  12. A novel antibody-based biomarker for chronic algal toxin exposure and sub-acute neurotoxicity.

    PubMed

    Lefebvre, Kathi A; Frame, Elizabeth R; Gulland, Frances; Hansen, John D; Kendrick, Preston S; Beyer, Richard P; Bammler, Theo K; Farin, Frederico M; Hiolski, Emma M; Smith, Donald R; Marcinek, David J

    2012-01-01

    The neurotoxic amino acid, domoic acid (DA), is naturally produced by marine phytoplankton and presents a significant threat to the health of marine mammals, seabirds and humans via transfer of the toxin through the foodweb. In humans, acute exposure causes a neurotoxic illness known as amnesic shellfish poisoning characterized by seizures, memory loss, coma and death. Regular monitoring for high DA levels in edible shellfish tissues has been effective in protecting human consumers from acute DA exposure. However, chronic low-level DA exposure remains a concern, particularly in coastal and tribal communities that subsistence harvest shellfish known to contain low levels of the toxin. Domoic acid exposure via consumption of planktivorous fish also has a profound health impact on California sea lions (Zalophus californianus) affecting hundreds of animals yearly. Due to increasing algal toxin exposure threats globally, there is a critical need for reliable diagnostic tests for assessing chronic DA exposure in humans and wildlife. Here we report the discovery of a novel DA-specific antibody response that is a signature of chronic low-level exposure identified initially in a zebrafish exposure model and confirmed in naturally exposed wild sea lions. Additionally, we found that chronic exposure in zebrafish caused increased neurologic sensitivity to DA, revealing that repetitive exposure to DA well below the threshold for acute behavioral toxicity has underlying neurotoxic consequences. The discovery that chronic exposure to low levels of a small, water-soluble single amino acid triggers a detectable antibody response is surprising and has profound implications for the development of diagnostic tests for exposure to other pervasive environmental toxins. PMID:22567140

  13. A novel antibody-based biomarker for chronic algal toxin exposure and sub-acute neurotoxicity

    USGS Publications Warehouse

    Lefebvre, Kathi A.; Frame, Elizabeth R.; Gulland, Frances; Hansen, John D.; Kendrick, Preston S.; Beyer, Richard P.; Bammler, Theo K.; Farin, Frederico M.; Hiolski, Emma M.; Smith, Donald R.; Marcinek, David J.

    2012-01-01

    The neurotoxic amino acid, domoic acid (DA), is naturally produced by marine phytoplankton and presents a significant threat to the health of marine mammals, seabirds and humans via transfer of the toxin through the foodweb. In humans, acute exposure causes a neurotoxic illness known as amnesic shellfish poisoning characterized by seizures, memory loss, coma and death. Regular monitoring for high DA levels in edible shellfish tissues has been effective in protecting human consumers from acute DA exposure. However, chronic low-level DA exposure remains a concern, particularly in coastal and tribal communities that subsistence harvest shellfish known to contain low levels of the toxin. Domoic acid exposure via consumption of planktivorous fish also has a profound health impact on California sea lions (Zalophus californianus) affecting hundreds of animals yearly. Due to increasing algal toxin exposure threats globally, there is a critical need for reliable diagnostic tests for assessing chronic DA exposure in humans and wildlife. Here we report the discovery of a novel DA-specific antibody response that is a signature of chronic low-level exposure identified initially in a zebrafish exposure model and confirmed in naturally exposed wild sea lions. Additionally, we found that chronic exposure in zebrafish caused increased neurologic sensitivity to DA, revealing that repetitive exposure to DA well below the threshold for acute behavioral toxicity has underlying neurotoxic consequences. The discovery that chronic exposure to low levels of a small, water-soluble single amino acid triggers a detectable antibody response is surprising and has profound implications for the development of diagnostic tests for exposure to other pervasive environmental toxins.

  14. Reduced growth of soybean seedlings after exposure to weak microwave radiation from GSM 900 mobile phone and base station.

    PubMed

    Halgamuge, Malka N; Yak, See Kye; Eberhardt, Jacob L

    2015-02-01

    The aim of this work was to study possible effects of environmental radiation pollution on plants. The association between cellular telephone (short duration, higher amplitude) and base station (long duration, very low amplitude) radiation exposure and the growth rate of soybean (Glycine max) seedlings was investigated. Soybean seedlings, pre-grown for 4 days, were exposed in a gigahertz transverse electromagnetic cell for 2?h to global system for mobile communication (GSM) mobile phone pulsed radiation or continuous wave (CW) radiation at 900?MHz with amplitudes of 5.7 and 41?V?m(-1) , and outgrowth was studied one week after exposure. The exposure to higher amplitude (41?V?m(-1)) GSM radiation resulted in diminished outgrowth of the epicotyl. The exposure to lower amplitude (5.7?V?m(-1)) GSM radiation did not influence outgrowth of epicotyl, hypocotyls, or roots. The exposure to higher amplitude CW radiation resulted in reduced outgrowth of the roots whereas lower CW exposure resulted in a reduced outgrowth of the hypocotyl. Soybean seedlings were also exposed for 5 days to an extremely low level of radiation (GSM 900?MHz, 0.56?V?m(-1)) and outgrowth was studied 2 days later. Growth of epicotyl and hypocotyl was found to be reduced, whereas the outgrowth of roots was stimulated. Our findings indicate that the observed effects were significantly dependent on field strength as well as amplitude modulation of the applied field. PMID:25644316

  15. Prospects for dynamic ISR tasking and interpretation based on standing orders to sensor networks

    NASA Astrophysics Data System (ADS)

    Pantaleev, Aleksandar; Josephson, John R.

    2007-04-01

    This research is intended to contribute to the development of automated and human-in-the-loop systems for higher level fusion to respond to the information requirements of command decision making. In tactical situations with short time constraints, the analysis of information requirements may take place in advance for certain classes of problems, and provided to commanders and their staff as part of the control and communications systems that come with sensor networks. In particular, it may be possible that certain standing orders can assume the role of Priority Intelligence Requirements. Standing orders to a sensor network are analogous to standing orders to Soldiers. Trained Soldiers presumably don't need to be told to report contact with hostiles, for example, or to report any sighting of civilians with weapons. Such standing orders define design goals and engineering requirements for sensor networks and their control and inference systems. Since such standing orders can be defined in advance for a class of situations, they minimize the need for situation-specific human analysis. Thus, standing orders should be able to drive automatic control of some network functions, automated fusion of sensor reports, and automated dissemination of fused information. We define example standing orders, and outline an algorithm for responding to one of them based on our experience in the field of multisensor fusion.

  16. Task-Based Core-Periphery Organization of Human Brain Dynamics

    PubMed Central

    Bassett, Danielle S.; Wymbs, Nicholas F.; Rombach, M. Puck; Porter, Mason A.; Mucha, Peter J.; Grafton, Scott T.

    2013-01-01

    As a person learns a new skill, distinct synapses, brain regions, and circuits are engaged and change over time. In this paper, we develop methods to examine patterns of correlated activity across a large set of brain regions. Our goal is to identify properties that enable robust learning of a motor skill. We measure brain activity during motor sequencing and characterize network properties based on coherent activity between brain regions. Using recently developed algorithms to detect time-evolving communities, we find that the complex reconfiguration patterns of the brain's putative functional modules that control learning can be described parsimoniously by the combined presence of a relatively stiff temporal core that is composed primarily of sensorimotor and visual regions whose connectivity changes little in time and a flexible temporal periphery that is composed primarily of multimodal association regions whose connectivity changes frequently. The separation between temporal core and periphery changes over the course of training and, importantly, is a good predictor of individual differences in learning success. The core of dynamically stiff regions exhibits dense connectivity, which is consistent with notions of core-periphery organization established previously in social networks. Our results demonstrate that core-periphery organization provides an insightful way to understand how putative functional modules are linked. This, in turn, enables the prediction of fundamental human capacities, including the production of complex goal-directed behavior. PMID:24086116

  17. ECONOMIC EVALUATION OF CO2 SEQUESTRATION TECHNOLOGIES TASK 4, BIOMASS GASIFICATION-BASED PROCESSING

    SciTech Connect

    Martha L. Rollins; Les Reardon; David Nichols; Patrick Lee; Millicent Moore; Mike Crim; Robert Luttrell; Evan Hughes

    2002-04-01

    Biomass derived energy currently accounts for about 3 quads of total primary energy use in the United States. Of this amount, about 0.8 quads are used for power generation. Several biomass energy production technologies exist today which contribute to this energy mix. Biomass combustion technologies have been the dominant source of biomass energy production, both historically and during the past two decades of expansion of modern biomass energy in the U. S. and Europe. As a research and development activity, biomass gasification has usually been the major emphasis as a method of more efficiently utilizing the energy potential of biomass, particularly wood. Numerous biomass gasification technologies exist today in various stages of development. Some are simple systems, while others employ a high degree of integration for maximum energy utilization. The purpose of this study is to conduct a technical and economic comparison of up to three biomass gasification technologies, including the carbon dioxide emissions reduction potential of each. To accomplish this, a literature search was first conducted to determine which technologies were most promising based on a specific set of criteria. During this reporting period, the technical and economic performances of the selected processes were evaluated using computer models and available literature. The results of these evaluations are summarized in this report.

  18. ECONOMIC EVALUATION OF CO2 SEQUESTRATION TECHNOLOGIES TASK 4, BIOMASS GASIFICATION-BASED PROCESSING

    SciTech Connect

    Martha L. Rollins; Les Reardon; David Nichols; Patrick Lee; Millicent Moore; Mike Crim; Robert Luttrell; Evan Hughes

    2002-06-01

    Biomass derived energy currently accounts for about 3 quads of total primary energy use in the United States. Of this amount, about 0.8 quads are used for power generation. Several biomass energy production technologies exist today which contribute to this energy mix. Biomass combustion technologies have been the dominant source of biomass energy production, both historically and during the past two decades of expansion of modern biomass energy in the U. S. and Europe. As a research and development activity, biomass gasification has usually been the major emphasis as a method of more efficiently utilizing the energy potential of biomass, particularly wood. Numerous biomass gasification technologies exist today in various stages of development. Some are simple systems, while others employ a high degree of integration for maximum energy utilization. The purpose of this study is to conduct a technical and economic comparison of up to three biomass gasification technologies, including the carbon dioxide emissions reduction potential of each. To accomplish this, a literature search was first conducted to determine which technologies were most promising based on a specific set of criteria. The technical and economic performances of the selected processes were evaluated using computer models and available literature. Using these results, the carbon sequestration potential of the three technologies was then evaluated. The results of these evaluations are given in this final report.

  19. Experimental investigations of sensor-based surface following tasks by a mobile manipulator

    SciTech Connect

    Reister, D.B.; Unseren, M.A.; Baker, J.E.; Pin, F.G.

    1993-10-01

    This paper discusses experimental investigations of the feasibility and requirements of simultaneous external-sensor-based-control of the wheeled platform and the manipulator of a mobile robot. The experiments involve 3-D arbitrary surface following by the manipulator while the platform moves along a predefined trajectory. A variety of concave and convex surfaces were used in the experiments, during which target and measured values of the platform and arm positions and orientations, together with the surface absolute location and normal estimates, were logged at 10 Hz. For all experiments, the data logs showed significant noise, at high frequency, in the calculated surface normal values despite smooth tracking of their target values by the arm and the platform, with typical closed loop delays between target and achieved values of the order of 100 msec. This high-frequency noise in the calculated values is conjectured to result mainly from the arm`s transmission cables compliance and backlash in the spherical wrist gears. On the other hand, the end-effector distance to the surface showed some low frequency errors of the order of {plus_minus}20%The two major sources of these low frequency errors appeared to reside respectively in the low values of the velocity bound and gain parameters utilized to filter the high frequency noise in the calculated normal values prior to using them as input to the arm control, and in the rolling contact of the platform`s rubber-coated wheels on the ground where significant errors in the platform`s positions and orientations can accumulate.

  20. Effect of repeated x-ray exposure on the resolution of amorphous selenium based x-ray imagers

    SciTech Connect

    Kabir, M. Z.; Chowdhury, L.; DeCrescenzo, G.; Tousignant, O.; Kasap, S. O.; Rowlands, J. A. [Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve W., Montreal, Quebec H3G 1M8 (Canada); Department of Medical Biophysics, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M5S 2H3 (Canada); ANRAD Corporation, 4950 Levy Street, Saint-Laurent (Montreal), Quebec H4R 2P1 (Canada); Department of Electrical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9 (Canada); Department of Medical Biophysics, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M5S 2H3, Canada and Thunder Bay Regional Research Institute, Lakehead University, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4 (Canada)

    2010-03-15

    Purpose: A numerical model and the experimental methods to study the x-ray exposure dependent change in the modulation transfer function (MTF) of amorphous selenium (a-Se) based active matrix flat panel imagers (AMFPIs) are described. The physical mechanisms responsible for the x-ray exposure dependent change in MTF are also investigated. Methods: A numerical model for describing the x-ray exposure dependent MTF of a-Se based AMFPIs has been developed. The x-ray sensitivity and MTF of an a-Se AMFPI have been measured as a function of exposure. The instantaneous electric field and free and trapped carrier distributions in the photoconductor layer are obtained by numerically solving the Poisson's equation, continuity equations, and trapping rate equations using the backward Euler finite difference method. From the trapped carrier distributions, a method for calculating the MTF due to incomplete charge collection is proposed. Results: The model developed in this work and the experimental data show a reasonably good agreement. The model is able to simultaneously predict the dependence of the sensitivity and MTF on accumulated exposure at different applied fields and bias polarities, with the same charge transport parameters that are typical of the particular a-Se photoconductive layer that is used in these AMFPIs. Under negative bias, the MTF actually improves with the accumulated x-ray exposure while the sensitivity decreases. The MTF enhancement with exposure decreases with increasing applied field. Conclusions: The most prevalent processes that control the MTF under negative bias are the recombination of drifting holes with previously trapped electrons (electrons remain in deep traps due to their long release times compared with the time scale of the experiments) and the deep trapping of drifting holes and electrons.

  1. A tensor-based morphometry analysis of regional differences in brain volume in relation to prenatal alcohol exposure.

    PubMed

    Meintjes, E M; Narr, K L; van der Kouwe, A J W; Molteno, C D; Pirnia, T; Gutman, B; Woods, R P; Thompson, P M; Jacobson, J L; Jacobson, S W

    2014-01-01

    Reductions in brain volumes represent a neurobiological signature of fetal alcohol spectrum disorders (FASD). Less clear is how regional brain tissue reductions differ after normalizing for brain size differences linked with FASD and whether these profiles can predict the degree of prenatal exposure to alcohol. To examine associations of regional brain tissue excesses/deficits with degree of prenatal alcohol exposure and diagnosis with and without correction for overall brain volume, tensor-based morphometry (TBM) methods were applied to structural imaging data from a well-characterized, demographically homogeneous sample of children diagnosed with FASD (n = 39, 9.6-11.0 years) and controls (n = 16, 9.5-11.0 years). Degree of prenatal alcohol exposure was significantly associated with regionally pervasive brain tissue reductions in: (1) the thalamus, midbrain, and ventromedial frontal lobe, (2) the superior cerebellum and inferior occipital lobe, (3) the dorsolateral frontal cortex, and (4) the precuneus and superior parietal lobule. When overall brain size was factored out of the analysis on a subject-by-subject basis, no regions showed significant associations with alcohol exposure. FASD diagnosis was associated with a similar deformation pattern, but few of the regions survived FDR correction. In data-driven independent component analyses (ICA) regional brain tissue deformations successfully distinguished individuals based on extent of prenatal alcohol exposure and to a lesser degree, diagnosis. The greater sensitivity of the continuous measure of alcohol exposure compared with the categorical diagnosis across diverse brain regions underscores the dose dependence of these effects. The ICA results illustrate that profiles of brain tissue alterations may be a useful indicator of prenatal alcohol exposure when reliable historical data are not available and facial features are not apparent. PMID:25057467

  2. A network-based approach for estimating pedestrian journey-time exposure to air pollution.

    PubMed

    Davies, Gemma; Whyatt, J Duncan

    2014-07-01

    Individual exposure to air pollution depends not only upon pollution concentrations in the surrounding environment, but also on the volume of air inhaled, which is determined by an individual's physiology and activity level. This study focuses on journey-time exposure, using network analysis in a GIS environment to identify pedestrian routes between multiple origins and destinations throughout the city of Lancaster, North West England. For each segment of a detailed footpath network, exposure was calculated accounting for PM2.5 concentrations (estimated using an atmospheric dispersion model) and respiratory minute volume (varying between individuals and with slope). For each of the routes generated the cumulative exposure to PM2.5 was estimated, allowing for easy comparison between multiple routes. Significant variations in exposure were found between routes depending on their geography, as well as in response to variations in background concentrations and meteorology between days. Differences in physiological characteristics such as age or weight were also seen to impact journey-time exposure considerably. In addition to assessing exposure for a given route, the approach was used to identify alternative routes that minimised journey-time exposure. Exposure reduction potential varied considerably between days, with even subtle shifts in route location, such as to the opposite side of the road, showing significant benefits. The method presented is both flexible and scalable, allowing for the interactions between physiology, activity level, pollution concentration and journey duration to be explored. In enabling physiology and activity level to be integrated into exposure calculations a more comprehensive estimate of journey-time exposure can be made, which has potential to provide more realistic inputs for epidemiological studies. PMID:24704957

  3. Relationships Between Adolescent Sexual Outcomes and Exposure to Sex in Media: Robustness to Propensity-Based Analysis.

    PubMed

    Collins, Rebecca L; Martino, Steven C; Elliott, Marc N; Miu, Angela

    2011-03-01

    Adolescent sexual health is a substantial problem in the U.S., and two recent studies have linked adolescent sexual behavior and/or outcomes to youths' exposure to sex in the media. Both studies had longitudinal survey designs and used covariate-adjusted regression analysis. Steinberg and Monahan (2010) reanalyzed data from one of these studies (Brown et al., 2006) using a propensity-score approach, arguing that this method better addresses the possibility of unobserved confounders. Based on their reanalysis, which found no relationship between media exposure and sexual behavior, they concluded that "Adolescents' Exposure to Sexy Media Does Not Hasten the Initiation of Sexual Intercourse." We subject data from the second study (Collins et al., 2004; Chandra et al., 2008) to reanalysis using a propensity-score approach. We find only modest reductions in two of the three previously documented associations, and no reduction in the third. Based on these findings, we conclude that there is an association between exposure to sex in the media and adolescent sexual outcomes. While the evidence does not prove causality, it is sufficient to advise caution among parents, develop interventions for youth, and work with media producers and distributors to reduce youth exposure to sexual content. PMID:24839301

  4. Natural Occurrence of Alternaria Toxins in Wheat-Based Products and Their Dietary Exposure in China

    PubMed Central

    Zhao, Kai; Shao, Bing; Yang, Dajin; Li, Fengqin; Zhu, Jianghui

    2015-01-01

    A total of 181 wheat flour and 142 wheat-based foods including dried noodle, steamed bread and bread collected in China were analyzed for alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN) and tenuazonic acid (TeA) by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. TeA was the predominant toxin found in 99.4% wheat flour samples at levels ranging from 1.76 ?g/kg to 520 ?g/kg. TEN was another Alternaria toxin frequently detected in wheat flour samples (97.2%) at levels between 2.72 ?g/kg and 129 ?g/kg. AOH and AME were detected in 11 (6.1%) samples at levels ranging from 16.0 ?g/kg to 98.7 ?g/kg (AOH) and in 165 (91.2%) samples with a range between 0.320 ?g/kg and 61.8 ?g/kg (AME). AOH was quantified at higher levels than AME with the ratio of AOH/AME ranging from 1.0 to 3.7. Significant linear regressions of correlation in toxin concentrations were observed between AOH and AME, AME and TeA, TEN and TeA, AOH+AME and TeA. At an average and 95th percentile, dietary exposure to AOH and AME in the Chinese general population and different age subgroups exceeded the relevant threshold value of toxicological concern (TTC), with the highest exposure found in children which deserves human health concern. TEN and TeA seem unlikely to be health concerns for the Chinese via wheat-based products but attention should be paid to synergistic or additive effects of TeA with AOH, AME, TEN and a further assessment will be performed once more data on toxicity-guided fractionation of the four toxins are available. It is necessary to conduct a systemic surveillance of Alternaria toxins in raw and processed foods in order to provide the scientific basis for making regulations on these toxins in China. PMID:26121047

  5. Elemental Carbon-Based Method for Monitoring Occupational Exposures to Particulate Diesel Exhaust

    Microsoft Academic Search

    M. E. Birch; R. A. Cary

    1996-01-01

    Diesel exhaust has been classified a probable human carcinogen, and the National Institute for Occupational Safety and Health (NIOSH) has recommended that employers reduce workers' exposures. Because diesel exhaust is a chemically complex mixture containing thousands of compounds, some measure of exposure must be selected. Previously used methods involving gravimetry or analysis of the soluble organic fraction of diesel soot

  6. Work Characteristics and Pesticide Exposures among Migrant Agricultural Families: A Community-Based Research Approach.

    ERIC Educational Resources Information Center

    McCauley, Linda A.; Lasarev, Michael R.; Higgins, Gregory; Rothlein, Joan; Muniz, Juan; Ebbert, Caren; Phillips, Jacki

    2001-01-01

    Assessment of pesticide exposure in 96 homes of migrant Latino farmworkers with preschool children found the most frequent pesticide residue to be azinphos-methyl (AZM). AZM levels in farmworker homes were related to distance from fields and number of resident agricultural workers. Children's play areas had potential for disproportionate exposure.…

  7. The Timing of Exposure in Clinic-Based Treatment for Childhood Anxiety Disorders

    ERIC Educational Resources Information Center

    Gryczkowski, Michelle R.; Tiede, Michael S.; Dammann, Julie E.; Jacobsen, Amy Brown; Hale, Lisa R.; Whiteside, Stephen P. H.

    2013-01-01

    The present study examines treatment length and timing of exposure from two child anxiety disorders clinics. Data regarding symptoms and treatment characteristics for 28 youth were prospectively obtained through self, parent, and therapist report at each session. Information regarding length of treatment, timing of exposure initiation, and…

  8. Developing Physical Exposure-Based Back Injury Risk Models Applicable to Manual Handling Jobs in Distribution Centers

    Microsoft Academic Search

    Steven A. Lavender; William S. Marras; Sue A. Ferguson; Riley E. Splittstoesser; Gang Yang

    2012-01-01

    Using our ultrasound-based “Moment Monitor,” exposures to biomechanical low back disorder risk factors were quantified in 195 volunteers who worked in 50 different distribution center jobs. Low back injury rates, determined from a retrospective examination of each company's Occupational Safety and Health Administration (OSHA) 300 records over the 3-year period immediately prior to data collection, were used to classify each

  9. Open Exposure of Telco Capabilities - Identification of Critical Success Factors for Location-Based Services in Open Telco

    Microsoft Academic Search

    Vesa Suikkola

    2010-01-01

    As of late, open exposure of telco capabilities has been a target of interest - much due to the success of open application programming interfaces on the Internet services market. Due to the innate ability of the mobile networks to know its users' locations, the location-based services market is an especially interesting area from the operator point of view. Operators

  10. The influence of thermal exposure on the microstructure and stress rupture property of DZ951 nickel-base alloy

    Microsoft Academic Search

    P. C. Xia; J. J. Yu; X. F. Sun; H. R. Guan; Z. Q. Hu

    2007-01-01

    The effect of long-term exposure on the microstructure and the stress rupture property of a directionally solidified nickel-base superalloy was investigated. The results show that the MC carbide coarsens and the content of Nb in carbide increases with the rise of aging time. ?? size increases and ?? phase rafts with the rise of aging time at different aging temperatures.

  11. Institutional review board challenges related to community-based participatory research on human exposure to environmental toxins: A case study

    Microsoft Academic Search

    Phil Brown; Rachel Morello-Frosch; J G Brody; Rebecca Gasior Altman; Ruthann A Rudel; Laura Senier; Carla Pérez; Ruth Simpson

    2010-01-01

    BACKGROUND: We report on the challenges of obtaining Institutional Review Board (IRB) coverage for a community-based participatory research (CBPR) environmental justice project, which involved reporting biomonitoring and household exposure results to participants, and included lay participation in research. METHODS: We draw on our experiences guiding a multi-partner CBPR project through university and state Institutional Review Board reviews, and other CBPR

  12. MEMBERSHIP BASED ORGANIZING OF POOR WOMEN Reflections After An Exposure and Dialogue Program with SEWA in Gujarat, India, January 2005

    Microsoft Academic Search

    Anonymous; Renana Jhabvala; Ravi Kanbur; Nidhi Mirani; Karl Osner; Carol Richards

    2005-01-01

    In January, 2005, a group of analysts and activists met in Gujarat at the invitation of SEWA to discuss papers presented at a conference on Membership Based Organizations of the Poor. The details of the conference are available at http:\\/\\/wiego.org\\/ahmedabad\\/. Somewhat unusually for academic conferences of this type, the discussions were preceded by an exposure to the lives of individual

  13. Physiologically based pharmacokinetic model useful in prediction of the influence of species, dose, and exposure route on perchloroethylene pharmacokinetics

    Microsoft Academic Search

    Cham E. Dallas; Xiao Mei Chen; Srinivasa Muralidhara; Peter Varkonyi; Randall L. Tackett; James V. Bruckner

    1995-01-01

    The ability of a physiologically based pharmacokinetic (PBPK) model to predict the uptake and elimination of perchloroethylene (PCE) in venous blood was evaluated by comparison of model simulations with experimental data for two species, two routes of exposure, and three dosage levels. Unanesthetized male Sprague?Dawley rats and beagle dogs were administered 1, 3, or 10 mg PCE\\/kg body weight in

  14. MEASUREMENT OF CHILDREN'S EXPOSURE TO PESTICIDES: ANALYSIS OF URINARY METABOLITE LEVELS IN A PROBABILITY-BASED SAMPLE

    EPA Science Inventory

    The Minnesota Children's Pesticide Exposure Study is a probability-based sample of 102 children 3-13 years old who were monitored for commonly used pesticides. During the summer of 1997, first-morning-void urine samples (1-3 per child) were obtained for 88% of study children a...

  15. NHEXAS PHASE I REGION 5 STUDY--EXPOSURE AND DOSE ASSESSMENT MODELING AND EVALUATION (EOHSI-AP-209-600)

    EPA Science Inventory

    This procedure describes the Exposure and Dose Assessment Modeling and Evaluation tasks. These tasks are as follows: (1) develop and evaluate schemes for the analysis, organization, retrieval, visualization, and management of the information collected by NHEXAS based on state-of-...

  16. An Assessment of Instant Messaging Interruptions on Knowledge Workers' Task Performance in E-Learning-Based Training

    ERIC Educational Resources Information Center

    Mansi, Gary R.

    2011-01-01

    The modern workplace environment is filled with interruptions due to the necessity of coworkers to communicate with each other. Studies have revealed that interruptions can disrupt the ability of a knowledge worker to concentrate on a task, which can impact task performance (TP). Communication interruptions are due, in part, to the unavoidable…

  17. Predictive engineering models based on the EPIC architecture for a multimodal high-performance human-computer interaction task

    Microsoft Academic Search

    David E. Kieras; Scott D. Wood; David E. Meyer

    1997-01-01

    Engineering models of human performance permit some aspects of usability of interface designs to be predicted from an analysis of the task, and thus they can replace to some extent expensive user-testing data. We successfully predicted human performance in telephone operator tasks with engineering models constructed in the EPIC (Executive Process-Interactive Control) architecture for human information processing, which is especially

  18. Predictive Engineering Models Based on the EPIC Architecture for a Multimodal High-Performance Human-Computer Interaction Task

    Microsoft Academic Search

    DAVID E. KIERAS; SCOTT D. WOOD; DAVID E. MEYER

    1996-01-01

    Engineering models of human performance permit some aspects of usability of interface designs to be predicted from an analysis of the task, and thus they can replace to some extent expensive user-testing data. We successfully predicted human performance in telephone operator tasks with engineering models constructed in the EPIC (Executive Process-Interac- tive Control) architecture for human information processing, which is

  19. Making fate and exposure models for freshwater ecotoxicity in life cycle assessment suitable for organic acids and bases.

    PubMed

    van Zelm, Rosalie; Stam, Gea; Huijbregts, Mark A J; van de Meent, Dik

    2013-01-01

    Freshwater fate and exposure factors were determined for organic acids and bases, making use of the knowledge on electrical interaction of ionizing chemicals and their sorption to particles. The fate factor represents the residence time in the environment whereas exposure factors equal the dissolved fraction of a chemical. Multimedia fate, exposure, and effect model USES-LCA was updated to take into account the influence of ionization, based upon the acid dissociation constant (pK(a)) of a chemical, and the environmental pH. Freshwater fate (FF) and exposure (XF) factors were determined for 415 acids and 496 bases emitted to freshwater, air, and soil. The relevance of taking account of the degree of ionization of chemicals was tested by determining the ratio (R) of the new vs. fate and exposure factors determined with USES-LCA suitable for neutral chemicals only. Our results show that the majority of freshwater fate and exposure factors of chemicals that are largely ionized in the environment are larger with the ionics model compared to the factors determined with the neutrals model version. R(FF) ranged from 2.4×10(-1) to 1.6×10(1) for freshwater emissions, from 1.2×10(-2) to 2.0×10(4) for soil emissions and from 5.8×10(-2) to 6.0×10(3) for air emissions, and R(XF) from 5.3×10(-1) to 2.2×10(1). Prediction of changed solid-water partitioning, implying a change in runoff and in removal via sedimentation, and prediction of negligible air-water partition coefficient, leading to negligible volatilization were the main contributors to the changes in freshwater fate factors. PMID:22884491

  20. Extricating sex and gender in air pollution research: a community-based study on cardinal symptoms of exposure.

    PubMed

    Oiamo, Tor H; Luginaah, Isaac N

    2013-09-01

    This study investigated sex and gender differences in cardinal symptoms of exposure to a mixture of ambient pollutants. A cross sectional population-based study design was utilized in Sarnia, ON, Canada. Stratified random sampling in census tracts of residents aged 18 and over recruited 804 respondents. Respondents completed a community health survey of chronic disease, general health, and socioeconomic indicators. Residential concentrations of NO?, SO?, benzene, toluene, ethylbenzene and o/m/p-xylene were estimated by land use regression on data collected through environmental monitoring. Classification and Regression Tree (CART) analysis was used to identify variables that interacted with sex and cardinal symptoms of exposure, and a series of logistic regression models were built to predict the reporting of five or more cardinal symptoms (5+ CS). Without controlling for confounders, higher pollution ranks increased the odds ratio (OR) of reporting 5+ CS by 28% (p < 0.01; Confidence Interval (CI): 1.07-1.54). Females were 1.52 (p < 0.05; CI: 1.03-2.26) times more likely more likely to report 5+ CS after controlling for income, age and chronic diseases. The CART analysis showed that allergies and occupational exposure classified the sample into the most homogenous groups of males and females. The likelihood of reporting 5+ CS among females was higher after stratifying the sample based on occupational exposure. However, stratifying by allergic disease resulted in no significant sex difference in symptom reporting. The results confirmed previous research that found pre-existing health conditions to increase susceptibility to ambient air pollution, but additionally indicated that stronger effects on females is partly due to autoimmune disorders. Furthermore, gender differences in occupational exposure confound the effect size of exposure in studies based on residential levels of air pollution. PMID:23975108

  1. Evaluation of individual-based and group-based exposure estimation of microbial agents in health effects associated with a damp building.

    PubMed

    Cho, Sook Ja; Cox-Ganser, Jean M; Kreiss, Kathleen; Park, Ju-Hyeong

    2013-07-01

    We evaluated attenuation in linear associations between microbial exposure and respiratory symptoms occurring when individual measurements of microbial agents were used for estimating employees' exposure compared with group means. Symptoms, which improved when away from the building (building-related, BR), and measurements of culturable fungi, ergosterol, and endotoxin in floor dust were obtained between 2001 and 2007 from four cross-sectional studies on occupants of a water-damaged building. We compared odds ratios from longitudinal health effect models using individual measurements at employees' workstations with those using floor (group) means. Estimated odds for BR respiratory symptoms in group-based analyses increased by 2 to 5 times compared with those from individual-based analyses for culturable fungi and ergosterol, although they were less precise. For endotoxin, we found substantially increased and significant odds in group-based analyses, while we found no associations in individual-based analyses for various symptoms. Our study suggested that the building floor was useful in constructing exposure groups for microbial agents in this water-damaged building for epidemiologic analysis. Our study showed that group-average exposure estimation provides less attenuated associations between exposures to microbial agents and health in damp indoor environments where measurement error and intrinsic temporal variability are often large. PMID:22968350

  2. Problems in evaluating health effects of occupational and environmental exposures

    SciTech Connect

    Gilbert, E.S.

    1981-01-01

    The assessment of health effects from low-level exposure to radiation is a matter of considerable controversy. Existing standards for exposure are based primarily on estimates of health effects obtained by extrapolation from effects of high-level exposures such as those experienced at Hiroshima and Nagasaki. Occupational and environmental exposures provide one source of data for this task. A number of studies of populations exposed in this manner have attracted recent attention. Because of the size of most of the groups and the magnitude of the exposures received, the amount that can be learned from such populations is severely limited. A number of the problems involved in analyzing and interpreting such data are addressed. Many of these problems are illustrated by a current study of the effects on mortality of occupational exposure to radiation at the Hanford plant.

  3. Conceptual design of a lunar base solar power plant lunar base systems study task 3.3

    NASA Technical Reports Server (NTRS)

    1988-01-01

    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.

  4. Conceptual design of a lunar base solar power plant lunar base systems study task 3.3

    NASA Astrophysics Data System (ADS)

    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.

  5. Analysis of Eisenia fetida earthworm responses to sub-lethal C60 nanoparticle exposure using (1)H-NMR based metabolomics.

    PubMed

    Lankadurai, Brian P; Nagato, Edward G; Simpson, André J; Simpson, Myrna J

    2015-10-01

    The enhanced production and environmental release of Buckminsterfullerene (C60) nanoparticles will likely increase the exposure and risk to soil dwelling organisms. We used (1)H NMR-based metabolomics to investigate the response of Eisenia fetida earthworms to sub-lethal C60 nanoparticle exposure in both contact and soil tests. Principal component analysis of (1)H NMR data showed clear separation between controls and exposed earthworms after just 2 days of exposure, however as exposure time increased the separation decreased in soil but increased in contact tests suggesting potential adaptation during soil exposure. The amino acids leucine, valine, isoleucine and phenylalanine, the nucleoside inosine, and the sugars glucose and maltose emerged as potential bioindicators of exposure to C60 nanoparticles. The significant responses observed in earthworms using NMR-based metabolomics after exposure to very low concentrations of C60 nanoparticles suggests the need for further investigations to better understand and predict their sub-lethal toxicity. PMID:26024814

  6. 4C/ID in medical education: How to design an educational program based on whole-task learning: AMEE Guide No. 93.

    PubMed

    Vandewaetere, Mieke; Manhaeve, Dominique; Aertgeerts, Bert; Clarebout, Geraldine; Van Merriënboer, Jeroen J G; Roex, Ann

    2015-01-01

    Medical education increasingly stresses that medical students should be prepared to take up multiple roles as a health professional. This requires the integrated acquisition of multiple competences such as clinical reasoning and decision making, communication skills and management skills. To promote such complex learning, instructional design has focused on the use of authentic, real-life learning tasks that students perform in a real or simulated task environment. The four-component instructional design model (4C/ID) model is an instructional design model that starts from the use of such tasks and provides students with a variety of learning tools facilitating the integrated acquisition of knowledge, skills and attitudes. In what follows, we guide the reader on how to implement educational programs based on the 4C/ID model and illustrate this with an example from general practice education. The developed learning environment is in line with the whole-task approach, where a learning domain is considered as a coherent, integrated whole and where teaching progresses from offering relatively simple, but meaningful, authentic whole tasks to more complex tasks. We describe the steps that were taken, from prototype over development to implementation, to build five learning modules (patient with diabetes; the young child with fever; axial skeleton; care for the elderly and physically undefined symptoms) that all focus on the integrated acquisition of the Canadian Medical Education Directives for Specialists roles in general practice. Furthermore, a change cycle for educational innovation is described that encompasses practice-based challenges and pitfalls about the collaboration between different stakeholders (students, developers and teachers) and the transition from traditional, fragmented and classroom-based learning to integrated and blended learning based on sound instructional design principles. PMID:25053377

  7. Reduced exposure to organic solvents by use of water-based paint systems in car repair shops

    Microsoft Academic Search

    Magne Bråtveit; BjørgEli Hollund; Bente E. Moen

    2004-01-01

    Objective The objective of this study was to determine to what extent the substitution of solvent-based paint by water-based paint has reduced potential exposure to organic solvents for spray painters in car repair shops. Methods Full-shift personal air sampling ( n=79) was carried out over 3 consecutive days in eight car repair shops. Blood samples on the Monday morning (

  8. Task-specific effects of reward on task switching.

    PubMed

    Umemoto, Akina; Holroyd, Clay B

    2015-07-01

    Although cognitive control and reinforcement learning have been researched extensively over the last few decades, only recently have studies investigated their interrelationship. An important unanswered question concerns how the control system decides what task to execute and how vigorously to carry out the task once selected. Based on a recent theory of control formulated according to principles of hierarchical reinforcement learning, we asked whether rewards can affect top-down control over task performance at the level of task representation. Participants were rewarded for correctly performing only one of two tasks in a standard task-switching experiment. Reaction times and error rates were lower for the reinforced task compared to the non-reinforced task. Moreover, the switch cost in error rates for the non-reinforced task was significantly larger compared to the reinforced task, especially for trials in which the imperative stimulus afforded different responses for the two tasks, resulting in a "non-paradoxical" asymmetric switch cost. These findings suggest that reinforcement at the task level resulted in greater application of top-down control rather than in stronger stimulus-response pathways for the rewarded task. PMID:24984832

  9. Prenatal Exposure to Maternal Bereavement and Childbirths in the Offspring: A Population-Based Cohort Study

    PubMed Central

    Plana-Ripoll, Oleguer; Olsen, Jørn; Andersen, Per Kragh; Gómez, Guadalupe; Cnattingius, Sven; Li, Jiong

    2014-01-01

    Introduction The decline in birth rates is a concern in public health. Fertility is partly determined before birth by the intrauterine environment and prenatal exposure to maternal stress could, through hormonal disturbance, play a role. There has been such evidence from animal studies but not from humans. We aimed to examine the association between prenatal stress due to maternal bereavement following the death of a relative and childbirths in the offspring. Materials and Methods This population-based cohort study included all subjects born in Denmark after 1968 and in Sweden after 1973 and follow-up started at the age of 12 years. Subjects were categorized as exposed if their mothers lost a close relative during pregnancy or the year before and unexposed otherwise. The main outcomes were age at first child and age-specific mean numbers of childbirths. Data was analyzed using Cox Proportional Hazards models stratified by gender and adjusted for several covariates. Subanalyses were performed considering the type of relative deceased and timing of bereavement. Results A total of 4,121,596 subjects were followed-up until up to 41 years of age. Of these subjects, 93,635 (2.3%) were exposed and 981,989 (23.8%) had at least one child during follow-up time. Compared to unexposed, the hazard ratio (HR) [95% confidence interval] of having at least one child for exposed males and females were 0.98 [0.96–1.01] and 1.01 [0.98–1.03], respectively. We found a slightly reduced probability of having children in females born to mothers who lost a parent with HR?=?0.97 [0.94–0.99] and increased probability in females born to mothers who lost another child (HR?=?1.09 [1.04–1.14]), the spouse (HR?=?1.29 [1.12–1.48]) or a sibling (HR?=?1.13 [1.01–1.27]). Conclusions Our results suggested no overall association between prenatal exposure to maternal stress and having a child in early adulthood but a longer time of follow-up is necessary in order to reach a firmer conclusion. PMID:25068458

  10. Some implications of an event-based definition of exposure to the risk of road accident.

    PubMed

    Elvik, Rune

    2015-03-01

    This paper proposes a new definition of exposure to the risk of road accident as any event, limited in space and time, representing a potential for an accident to occur by bringing road users close to each other in time or space of by requiring a road user to take action to avoid leaving the roadway. A typology of events representing a potential for an accident is proposed. Each event can be interpreted as a trial as defined in probability theory. Risk is the proportion of events that result in an accident. Defining exposure as events demanding the attention of road users implies that road users will learn from repeated exposure to these events, which in turn implies that there will normally be a negative relationship between exposure and risk. Four hypotheses regarding the relationship between exposure and risk are proposed. Preliminary tests support these hypotheses. Advantages and disadvantages of defining exposure as specific events are discussed. It is argued that developments in vehicle technology are likely to make events both observable and countable, thus ensuring that exposure is an operational concept. PMID:25560900

  11. Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

    PubMed Central

    Ragettli, Martina S.; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E.; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C.

    2014-01-01

    We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m?3, range: 21–61) than with a dispersion model with a lower resolution (39 ± 5 µg m?3; range: 24–51), and a land use regression model (41 ± 5 µg m?3; range: 24–54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas. PMID:24823664

  12. QT variability during initial exposure to sotalol: experience based on a large electronic medical record

    PubMed Central

    Weeke, Peter; Delaney, Jessica; Mosley, Jonathan D.; Wells, Quinn; Van Driest, Sara; Norris, Kris; Kucera, Gayle; Stubblefield, Tanya; Roden, Dan M.

    2013-01-01

    Aims A prolonged QT interval is associated with increased risk of Torsades de pointes (TdP) and may be fatal. We sought to investigate the extent to which clinical covariates affect the change in QT interval among ‘real-world’ patients treated with sotalol and followed in an electronic medical record (EMR) system. Methods and results We used clinical alerts in our EMR system to identify all patients in whom a new prescription for sotalol was written (2001–11). Rate-corrected QT (QTc) was calculated by Bazett's formula. Correlates of sotalol-induced change in the QTc interval and sotalol discontinuation were examined using linear and logistic regression, respectively. Overall, 541 sotalol-exposed patients were identified (n = 200 women, 37%). The mean first sotalol dose was 86 ± 39 mg, age 64 ± 13 years, and BMI 30 ± 7 kg/m2. Atrial fibrillation/flutter was the predominant indication (92.2%). After initial exposure, the change in the QTc interval from baseline was highly variable: ?QTc after 2 h = 3 ± 42 ms (P = 0.17) and 11 ± 37 ms after ?48 h (P < 0.001). Multivariable linear regression analysis identified female gender and age, reduced left ventricular ejection fraction, high sotalol dose, hypertrophic cardiomyopathy, and loop diuretic co-administration as correlates of increased ?QTc at ?48 h (P < 0.05 for all). Within 3 days of initiation, 12% discontinued sotalol of which 31% were because of exaggerated QTc prolongation. One percent developed TdP. Conclusion In this EMR-based cohort, the increase in QTc with sotalol initiation was highly variable, and multiple clinical factors contributed. These data represent an important step in ongoing work to identify real-world patients likely to tolerate long-term therapy and reinforces the utility of EMR-based cohorts as research tools. PMID:23787903

  13. Physiologically based assessment of human exposure to urban air pollutants and its significance for public health risk evaluation.

    PubMed Central

    Vostal, J J

    1994-01-01

    Exact measurements or modeling of human exposures to environmental pollutants are of crucial importance for a realistic evaluation of public health risks. Current concepts, however, often use assumptions that result in overly conservative assessments of public health risks. Too frequently the dose of the pollutant retained in the body is approximated by oversimplified predictions assuming that all that is inhaled remains in the organism, that pollutant concentrations in various microenvironments are identical to those recorded by remote monitors, that the residence indicates the site where people spend all their time, and that the urban population is continuously exposed to outdoor air for 24 hr/day and 70 years/lifetime. The review shows that in intermittent exposures only a fraction of inhaled toxicants remains in the body, that pollutant concentrations differ largely from one microenvironment to another, and that human activity patterns must be incorporated in every realistic exposure assessments. Specifically, the probability of being exposed to a short peak of ozone is predetermined in variable urban concentrations primarily by the coincidence of exercising outdoors at the time and site of elevated ozone levels. When combined with a physiologically based exposure evaluation, this probabilistic approach provides a scientifically sound estimate of actual occurrences of adverse exposures and a realistic assessment of potential health hazards. Images Figure 2. Figure 4. Figure 5. PMID:7821283

  14. Hypericin-based photodynamic therapy induces surface exposure of damage-associated molecular patterns like HSP70 and calreticulin.

    PubMed

    Garg, Abhishek D; Krysko, Dmitri V; Vandenabeele, Peter; Agostinis, Patrizia

    2012-02-01

    Surface-exposed HSP70 and calreticulin are damage-associated molecular patterns (DAMPs) crucially involved in modulating the success of cancer therapy. Photodynamic therapy (PDT) involves the administration of a photosensitising (PTS) agent followed by visible light-irradiation. The reactive oxygen species that are thus generated directly kill tumours by damaging their microvasculature and inducing a local inflammatory reaction. PDT with the PTS photofrin is associated with DAMPs exposure, but the same is not true for other PTSs. Here, we show that when cancer cells are treated with hypericin-based PDT (Hyp-PDT), they surface-expose both HSP70 and calreticulin (CRT). Induction of CRT exposure was not accompanied by co-exposure of ERp57, but this did not compromise the ability of the exposed CRT to regulate the phagocytosis of Hyp-PDT-treated cancer cells by dendritic cells. Interestingly, we found that Hyp-PDT-induced CRT exposure (in contrast to anthracycline-induced CRT exposure) was independent of the presence of ERp57. Our results indicate that Hyp-PDT is a potential anti-cancer immunogenic modality. PMID:22193987

  15. Changes in task-based effective connectivity in language networks following rehabilitation in post-stroke patients with aphasia

    PubMed Central

    Kiran, Swathi; Meier, Erin L.; Kapse, Kushal J.; Glynn, Peter A.

    2015-01-01

    In this study, we examined regions in the left and right hemisphere language network that were altered in terms of the underlying neural activation and effective connectivity subsequent to language rehabilitation. Eight persons with chronic post-stroke aphasia and eight normal controls participated in the current study. Patients received a 10 week semantic feature-based rehabilitation program to improve their skills. Therapy was provided on atypical examples of one trained category while two control categories were monitored; the categories were counterbalanced across patients. In each fMRI session, two experimental tasks were conducted: (a) picture naming and (b) semantic feature verification of trained and untrained categories. Analysis of treatment effect sizes revealed that all patients showed greater improvements on the trained category relative to untrained categories. Results from this study show remarkable patterns of consistency despite the inherent variability in lesion size and activation patterns across patients. Across patients, activation that emerged as a function of rehabilitation on the trained category included bilateral IFG, bilateral SFG, LMFG, and LPCG for picture naming; and bilateral IFG, bilateral MFG, LSFG, and bilateral MTG for semantic feature verification. Analysis of effective connectivity using Dynamic Causal Modeling (DCM) indicated that LIFG was the consistently significantly modulated region after rehabilitation across participants. These results indicate that language networks in patients with aphasia resemble normal language control networks and that this similarity is accentuated by rehabilitation. PMID:26106314

  16. Association Between Vision Impairment and Driving Exposure in Older Adults Aged 70 Years and Over: A Population-Based Examination

    PubMed Central

    Sandlin, Daniel; McGwin, Gerald; Owsley, Cynthia

    2012-01-01

    Purpose To examine the relationship between vision impairment and driving exposure (amount of driving one does) in a population-based sample of older drivers, and to examine to what extent cognitive status impacts this relationship. Methods Enrollees consisted of a population-based sample of older adults from Alabama who were ? 70 years old, held a current driver’s license, and had driven within the last 3 months. Three aspects of visual function were measured under binocular conditions – habitual distance visual acuity, contrast sensitivity, and visual processing speed. General cognitive status was assessed with the Mini-mental status examination. Driving exposure was estimated by the Driving Habits Questionnaire that asked about the number of miles, places, trips and days driven per week. Results Drivers with impaired contrast sensitivity exhibited reduced annual mileage, and a decreased number of places and trips driven per week compared to those with normal contrast sensitivity, even after adjustment for other factors. Slowed visual processing speed was associated with reduced number of days driven per week after adjustment. Visual acuity deficit was not associated with changes in driving exposure. Cognitive status did not impact any of the associations between vision impairment and driving exposure. Conclusion Older drivers with contrast sensitivity impairment exhibit reduced driving exposure in terms of number of trips and places they drive per week, as well as decreased annual mileage. These apparent self-regulatory practices should be viewed as adaptive since contrast sensitivity impairment elevates motor vehicle collision (MVC) risk and reduction in driving exposure can reduce MVC risk. PMID:23601553

  17. Young Learners' Interactional Development in Task-Based Paired-Assessment in Their First and Foreign Languages: A Case of English Learners in China

    ERIC Educational Resources Information Center

    Butler, Yuko Goto; Zeng, Wei

    2015-01-01

    In response to the growing interest in evaluating young learners' foreign language (FL) performance, this study aims to deepen our understanding of young learners' developmental differences in interaction during task-based paired-language assessments. To examine age effects separately from the effect of general language proficiency, we analysed…

  18. The Effect of Organizational Justice on Contextual Performance, Counterproductive Work Behaviors, and Task Performance: Investigating the moderating role of ability-based emotional intelligence

    Microsoft Academic Search

    Dwayne Devonish; Dion Greenidge

    2010-01-01

    This study tested the direct effects of three dimensions of organizational justice – distributive justice, procedural justice, and interactional justice – on contextual performance, counterproductive work behaviors, and task performance. The study also examined the moderating effects of an ability measure of emotional intelligence (EI) on the justice–performance relationship. Based on the data from 211 employees across nine organizations from

  19. Multi-Agent System-Based Fuzzy Controller Design with Genetic Tuning for a Mobile Manipulator Robot in the Hand Over Task

    Microsoft Academic Search

    Mustafa Suphi Erden; Kemal Leblebicioglu; Ugur Halici

    2004-01-01

    This paper presents an application of the multi-agent system approach to a service mobile manipulator robot that interacts with a human during an object delivery and hand-over task in two dimensions. The base, elbow and shoulder of the robot are identified as three different agents, and are controlled using fuzzy control. The control variables of the controllers are linear velocity

  20. A group-based tasks allocation algorithm for the optimization of long leave opportunities in academic departments

    NASA Astrophysics Data System (ADS)

    Eyono Obono, S. D.; Basak, Sujit Kumar

    2011-12-01

    The general formulation of the assignment problem consists in the optimal allocation of a given set of tasks to a workforce. This problem is covered by existing literature for different domains such as distributed databases, distributed systems, transportation, packets radio networks, IT outsourcing, and teaching allocation. This paper presents a new version of the assignment problem for the allocation of academic tasks to staff members in departments with long leave opportunities. It presents the description of a workload allocation scheme and its algorithm, for the allocation of an equitable number of tasks in academic departments where long leaves are necessary.

  1. Strategic backdrop analysis for fossil fuel planning. Task 2 report (New Task Series), The Base Case. Report 473-117-08/01

    SciTech Connect

    Not Available

    1980-08-01

    This report describes a base case analysis performed using the strategic backdrop analytical framework developed by The Futures Group to facilitate fossil fuel planning within the Department of Energy. It builds upon the data base compiled in the default case previously submitted but uses a different set of energy technology assumptions. Objectives of the strategic backdrop analysis project are: (1) to delineate alternative socioeconomic futures or target worlds for the United States and to derive, for each world, the amount of energy needed to sustain its level of economic activity and lifestyle, assuming no technological changes; (2) to construct an analytical framework that accounts for the flow of energy from the disaggregated end-use target demand sectors back through the distribution and conversion processes to primary resource requirements; (3) to use this framework 1) to analyze how alternative government policies and associated new technologies can change the primary resource needs and fuel mix while still providing the same level of end-use energy service for the target world, and 2) to highlight resource constraints, program inconsistencies, and economic, environmental, and social implications; (4) to transfer to DOE personnel the methodology for generating energy targets and accounting for important characteristics of alternative energy policies and technologies.

  2. RAMAN SPECTROSCOPY-BASED METABOLOMICS FOR DIFFERENTIATING EXPOSURES TO TRIAZOLE FUNGICIDES USING RAT URINE

    EPA Science Inventory

    Normal Raman spectroscopy was evaluated as a metabolomic tool for assessing the impacts of exposure to environmental contaminants, using rat urine collected during the course of a toxicological study. Specifically, one of three triazole fungicides, myclobutanil, propiconazole or ...

  3. The timing of exposure in clinic-based treatment for childhood anxiety disorders.

    PubMed

    Gryczkowski, Michelle R; Tiede, Michael S; Dammann, Julie E; Jacobsen, Amy Brown; Hale, Lisa R; Whiteside, Stephen P H

    2013-03-01

    The present study examines treatment length and timing of exposure from two child anxiety disorders clinics. Data regarding symptoms and treatment characteristics for 28 youth were prospectively obtained through self, parent, and therapist report at each session. Information regarding length of treatment, timing of exposure initiation, and drop-out rates were compared with those obtained through efficacy and effectiveness trials of manualized treatment for anxious youth. Findings from the authors' clinical data revealed significantly shorter treatment duration with exposures implemented sooner than in the previous studies. Dropout rates were significantly higher than in the efficacy trial but comparable with the effectiveness trial. Outcome data from a subset of eight patients revealed large effect sizes. These findings suggest that effective treatment can be shorter and more focused on exposure than is often outlined in manuals and have important implications for outcome research and dissemination. PMID:23548341

  4. The timing of exposure in clinic-based treatment for childhood anxiety disorders.

    PubMed

    Gryczkowski, Michelle R; Tiede, Michael S; Dammann, Julie E; Brown Jacobsen, Amy; Hale, Lisa R; Whiteside, Stephen P H

    2013-01-01

    The present study examines treatment length and timing of exposure from two child anxiety disorders clinics. Data regarding symptoms and treatment characteristics for 28 youth were prospectively obtained through self, parent, and therapist report at each session. Information regarding length of treatment, timing of exposure initiation, and drop-out rates were compared with those obtained through efficacy and effectiveness trials of manualized treatment for anxious youth. Findings from the authors' clinical data revealed significantly shorter treatment duration with exposures implemented sooner than in the previous studies. Dropout rates were significantly higher than in the efficacy trial but comparable with the effectiveness trial. Outcome data from a subset of eight patients revealed large effect sizes. These findings suggest that effective treatment can be shorter and more focused on exposure than is often outlined in manuals and have important implications for outcome research and dissemination. PMID:23012686

  5. Task-oriented rehabilitation robotics.

    PubMed

    Schweighofer, Nicolas; Choi, Younggeun; Winstein, Carolee; Gordon, James

    2012-11-01

    Task-oriented training is emerging as the dominant and most effective approach to motor rehabilitation of upper extremity function after stroke. Here, the authors propose that the task-oriented training framework provides an evidence-based blueprint for the design of task-oriented robots for the rehabilitation of upper extremity function in the form of three design principles: skill acquisition of functional tasks, active participation training, and individualized adaptive training. The previous robotic systems that incorporate elements of task-oriented trainings are then reviewed. Finally, the authors critically analyze their own attempt to design and test the feasibility of a TOR robot, ADAPT (Adaptive and Automatic Presentation of Tasks), which incorporates the three design principles. Because of its task-oriented training-based design, ADAPT departs from most other current rehabilitation robotic systems: it presents realistic functional tasks in which the task goal is constantly adapted, so that the individual actively performs doable but challenging tasks without physical assistance. To maximize efficacy for a large clinical population, the authors propose that future task-oriented robots need to incorporate yet-to-be developed adaptive task presentation algorithms that emphasize acquisition of fine motor coordination skills while minimizing compensatory movements. PMID:23080042

  6. Genetically based N-acetyltransferase metabolic polymorphism and low-level environmental exposure to carcinogens

    Microsoft Academic Search

    Paolo Vineis; Helmut Bartsch; Neil Caporaso; Anita M. Harrington; Fred F. Kadlubar; Maria Teresa Landi; Christian Malaveille; Peter G. Shields; Paul Skipper; Glenn Talaska; Steven R. Tannenbaum

    1994-01-01

    THE metabolic activation or inactivation of carcinogens varies considerably in human populations, and is partly genetically determined1,2. Inter-individual variability in the susceptibility to carcinogens may be particularly important at low degrees of environmental exposure. Examples of probable human carcinogens that present widespread low-dose exposures are environmental tobacco smoke and diesel exhaust3,4. We have determined levels of DNA adducts in bladder

  7. The impact of road traffic noise on cognitive performance in attention-based tasks depends on noise level even within moderate-level ranges.

    PubMed

    Schlittmeier, Sabine J; Feil, Alexandra; Liebl, Andreas; Hellbr Ck, J Rgen

    2015-01-01

    Little empirical evidence is available regarding the effects of road traffic noise on cognitive performance in adults, although traffic noise can be heard at many offices and home office workplaces. Our study tested the impact of road traffic noise at different levels (50 dB(A), 60 dB(A), 70 dB(A)) on performance in three tasks that differed with respect to their dependency on attentional and storage functions, as follows: The Stroop task, in which performance relied predominantly on attentional functions (e.g., inhibition of automated responses; Experiment 1: n = 24); a non-automated multistage mental arithmetic task calling for both attentional and storage functions (Exp. 2: n = 18); and verbal serial recall, which placed a burden predominantly on storage functions (Experiment 3: n = 18). Better performance was observed during moderate road traffic noise at 50 dB(A) compared to loud traffic noise at 70 dB(A) in attention-based tasks (Experiments 1-2). This contrasted with the effects of irrelevant speech (60 dB(A)), which was included in the experiments as a well-explored and common noise source in office settings. A disturbance impact of background speech was only given in the two tasks that called for storage functions (Experiments 2-3). In addition to the performance data, subjective annoyance ratings were collected. Consistent with the level effect of road traffic noise found in the performance data, a moderate road traffic noise at 50 dB(A) was perceived as significantly less annoying than a loud road traffic noise at 70 dB(A), which was found, however, independently of the task at hand. Furthermore, the background sound condition with the highest detrimental performance effect in a task was also rated as most annoying in this task, i.e., traffic noise at 70 dB(A) in the Stroop task, and background speech in the mental arithmetic and serial recall tasks. PMID:25913554

  8. Critical-Path and Priority based Algorithms for Scheduling Workflows with Parameter Sweep Tasks on Global Grids

    Microsoft Academic Search

    Tianchi Ma; Rajkumar Buyya

    2005-01-01

    Parameter-sweep has been widely adopted in large numbers of scientific applications. Parameter-sweep features need to be incorporated into Grid workflows so as to increase the scale and scope of such applications. New scheduling mechanisms and algorithms are required to provide optimized policy for resource allocation and task arrangement in such a case. This paper addresses scheduling sequential parameter-sweep tasks in

  9. Comparison of seven performance measures in a time-delayed manipulation task. [with Rancho arm using minicomputer-based data taker

    NASA Technical Reports Server (NTRS)

    Hill, J. W.

    1976-01-01

    Real-time performance data was collected during a pick-up task carried out with a Rancho master-slave manipulator using a minicomputer-based data taker. In addition to the usual task-time measurements, computer algorithms to integrate the energy consumed and to count and time the number of moves were implemented. In addition to these measures, several derived measures such as the fraction of time moving (MRATIO) and mean time per move (MBAR) were obtained in an off-line analysis. Preliminary results of the time delay experiment indicate that two new measures, MRATIO and MBAR, are almost an order of magnitude more sensitive than task time, the conventional measure, in determining performance changes with transmission delays in the range from 0.0 to 1.0s.

  10. Potential for Occupational Exposure to Engineered Carbon-Based Nanomaterials in Environmental Laboratory Studies

    PubMed Central

    Johnson, David R.; Methner, Mark M.; Kennedy, Alan J.; Steevens, Jeffery A.

    2010-01-01

    Background The potential exists for laboratory personnel to be exposed to engineered carbon-based nanomaterials (CNMs) in studies aimed at producing conditions similar to those found in natural surface waters [e.g., presence of natural organic matter (NOM)]. Objective The goal of this preliminary investigation was to assess the release of CNMs into the laboratory atmosphere during handling and sonication into environmentally relevant matrices. Methods We measured fullerenes (C60), underivatized multiwalled carbon nanotubes (raw MWCNT), hydroxylated MWCNT (MWCNT-OH), and carbon black (CB) in air as the nanomaterials were weighed, transferred to beakers filled with reconstituted freshwater, and sonicated in deionized water and reconstituted freshwater with and without NOM. Airborne nanomaterials emitted during processing were quantified using two hand-held particle counters that measure total particle number concentration per volume of air within the nanometer range (10–1,000 nm) and six specific size ranges (300–10,000 nm). Particle size and morphology were determined by transmission electron microscopy of air sample filters. Discussion After correcting for background particle number concentrations, it was evident that increases in airborne particle number concentrations occurred for each nanomaterial except CB during weighing, with airborne particle number concentrations inversely related to particle size. Sonicating nanomaterial-spiked water resulted in increased airborne nanomaterials, most notably for MWCNT-OH in water with NOM and for CB. Conclusion Engineered nanomaterials can become airborne when mixed in solution by sonication, especially when nanomaterials are functionalized or in water containing NOM. This finding indicates that laboratory workers may be at increased risk of exposure to engineered nanomaterials. PMID:20056572

  11. A case study of a precision fertilizer application task generation for wheat based on classified hyperspectral data from UAV combined with farm history data

    NASA Astrophysics Data System (ADS)

    Kaivosoja, Jere; Pesonen, Liisa; Kleemola, Jouko; Pölönen, Ilkka; Salo, Heikki; Honkavaara, Eija; Saari, Heikki; Mäkynen, Jussi; Rajala, Ari

    2013-10-01

    Different remote sensing methods for detecting variations in agricultural fields have been studied in last two decades. There are already existing systems for planning and applying e.g. nitrogen fertilizers to the cereal crop fields. However, there are disadvantages such as high costs, adaptability, reliability, resolution aspects and final products dissemination. With an unmanned aerial vehicle (UAV) based airborne methods, data collection can be performed cost-efficiently with desired spatial and temporal resolutions, below clouds and under diverse weather conditions. A new Fabry-Perot interferometer based hyperspectral imaging technology implemented in an UAV has been introduced. In this research, we studied the possibilities of exploiting classified raster maps from hyperspectral data to produce a work task for a precision fertilizer application. The UAV flight campaign was performed in a wheat test field in Finland in the summer of 2012. Based on the campaign, we have classified raster maps estimating the biomass and nitrogen contents at approximately stage 34 in the Zadoks scale. We combined the classified maps with farm history data such as previous yield maps. Then we generalized the combined results and transformed it to a vectorized zonal task map suitable for farm machinery. We present the selected weights for each dataset in the processing chain and the resultant variable rate application (VRA) task. The additional fertilization according to the generated task was shown to be beneficial for the amount of yield. However, our study is indicating that there are still many uncertainties within the process chain.

  12. A coordinate-based ALE functional MRI meta-analysis of brain activation during verbal fluency tasks in healthy control subjects

    PubMed Central

    2014-01-01

    Background The processing of verbal fluency tasks relies on the coordinated activity of a number of brain areas, particularly in the frontal and temporal lobes of the left hemisphere. Recent studies using functional magnetic resonance imaging (fMRI) to study the neural networks subserving verbal fluency functions have yielded divergent results especially with respect to a parcellation of the inferior frontal gyrus for phonemic and semantic verbal fluency. We conducted a coordinate-based activation likelihood estimation (ALE) meta-analysis on brain activation during the processing of phonemic and semantic verbal fluency tasks involving 28 individual studies with 490 healthy volunteers. Results For phonemic as well as for semantic verbal fluency, the most prominent clusters of brain activation were found in the left inferior/middle frontal gyrus (LIFG/MIFG) and the anterior cingulate gyrus. BA 44 was only involved in the processing of phonemic verbal fluency tasks, BA 45 and 47 in the processing of phonemic and semantic fluency tasks. Conclusions Our comparison of brain activation during the execution of either phonemic or semantic verbal fluency tasks revealed evidence for spatially different activation in BA 44, but not other regions of the LIFG/LMFG (BA 9, 45, 47) during phonemic and semantic verbal fluency processing. PMID:24456150

  13. Estimate of safe human exposure levels for lunar dust based on comparative benchmark dose modeling.

    PubMed

    James, John T; Lam, Chiu-Wing; Santana, Patricia A; Scully, Robert R

    2013-04-01

    Brief exposures of Apollo astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure to lunar dust. The United States and other space faring nations intend to return to the moon for extensive exploration within a few decades. In the meantime, habitats for that exploration, whether mobile or fixed, must be designed to limit human exposure to lunar dust to safe levels. Herein we estimate safe exposure limits for lunar dust collected during the Apollo 14 mission. We instilled three respirable-sized (?2 ? mass median diameter) lunar dusts (two ground and one unground) and two standard dusts of widely different toxicities (quartz and TiO?) into the respiratory system of rats. Rats in groups of six were given 0, 1, 2.5 or 7.5?mg of the test dust in a saline-Survanta® vehicle, and biochemical and cellular biomarkers of toxicity in lung lavage fluid were assayed 1 week and one month after instillation. By comparing the dose--response curves of sensitive biomarkers, we estimated safe exposure levels for astronauts and concluded that unground lunar dust and dust ground by two different methods were not toxicologically distinguishable. The safe exposure estimates were 1.3?±?0.4?mg/m³ (jet-milled dust), 1.0?±?0.5?mg/m³ (ball-milled dust) and 0.9?±?0.3?mg/m³ (unground, natural dust). We estimate that 0.5-1?mg/m³ of lunar dust is safe for periodic human exposures during long stays in habitats on the lunar surface. PMID:23614726

  14. Cadmium exposure via diet and its implication on the derivation of health-based soil screening values in China.

    PubMed

    Zhong, Mao-Sheng; Jiang, Lin; Han, Dan; Xia, Tian-Xiang; Yao, Jue-Jun; Jia, Xiao-Yang; Peng, Chao

    2015-07-01

    The cadmium (Cd) intake rates via diet of adults from different regions in China were between 0.160 and 0.557??g/(kg BW·day), which were less than the provisional tolerable monthly intake (0.833??g/(kg BW·day)) issued by Food and Agriculture Organization/World Health Organization in 2010, but higher than the one (0.365??g/(kg BW·day)) issued by the European Food Safety Authority in 2011, to protect children, vegetarians and people living in heavily contaminated regions, and the intake rate of children (1.007??g/(kg BW·day)) at the national scale was higher than the values recommended by the above institutes and those of adults. Vegetables were the critical contributors, followed by rice, flour, meats and aquatic products. Cd concentration in vegetable was the most sensitive factor in calculating the intake rate, followed by its contents in rice and aquatic products, and the intake rate of flour, indicating that more attention should be given to these parameters in future total diet surveys. When dietary exposure was incorporated, the derived national screening value of Cd under commercial scenario was reduced from 825 to 458?mg/kg, while the values of the north, south, Beijing and Shanghai were reduced to 627, 365, 693 and 489?mg/kg, respectively, indicating that the hazard would be underestimated if dietary exposure was not taken into account, especially for the south. The great variance between the screening values was due to the varied Cd intake rates, which indicated that deriving a screening value for each specific area based on its corresponding exposure characteristics was more appropriate. The national screening level for the residential scenario derived theoretically based on the dietary exposure characteristics of children was a negative value, meaning that the dietary intake rate was above the tolerable value. The method used in the United Kingdom to derive soil guideline values when non-soil exposure accounted for more than half of the maximum tolerable daily intake dose may be an appropriate estimate, but the exact ratio assigned to soil exposure should be assessed comprehensively based on a more sophisticated dietary exposure survey and the corresponding economic implications. PMID:25736161

  15. Evaluating the effect of human activity patterns on air pollution exposure using an integrated field-based and agent-based modelling framework

    NASA Astrophysics Data System (ADS)

    Schmitz, Oliver; Beelen, Rob M. J.; de Bakker, Merijn P.; Karssenberg, Derek

    2015-04-01

    Constructing spatio-temporal numerical models to support risk assessment, such as assessing the exposure of humans to air pollution, often requires the integration of field-based and agent-based modelling approaches. Continuous environmental variables such as air pollution are best represented using the field-based approach which considers phenomena as continuous fields having attribute values at all locations. When calculating human exposure to such pollutants it is, however, preferable to consider the population as a set of individuals each with a particular activity pattern. This would allow to account for the spatio-temporal variation in a pollutant along the space-time paths travelled by individuals, determined, for example, by home and work locations, road network, and travel times. Modelling this activity pattern requires an agent-based or individual based modelling approach. In general, field- and agent-based models are constructed with the help of separate software tools, while both approaches should play together in an interacting way and preferably should be combined into one modelling framework, which would allow for efficient and effective implementation of models by domain specialists. To overcome this lack in integrated modelling frameworks, we aim at the development of concepts and software for an integrated field-based and agent-based modelling framework. Concepts merging field- and agent-based modelling were implemented by extending PCRaster (http://www.pcraster.eu), a field-based modelling library implemented in C++, with components for 1) representation of discrete, mobile, agents, 2) spatial networks and algorithms by integrating the NetworkX library (http://networkx.github.io), allowing therefore to calculate e.g. shortest routes or total transport costs between locations, and 3) functions for field-network interactions, allowing to assign field-based attribute values to networks (i.e. as edge weights), such as aggregated or averaged concentration values. We demonstrate the approach by using six land use regression (LUR) models developed in the ESCAPE (European Study of Cohorts for Air Pollution Effects) project. These models calculate several air pollutants (e.g. NO2, NOx, PM2.5) for the entire Netherlands at a high (5 m) resolution. Using these air pollution maps, we compare exposure of individuals calculated at their x, y location of their home, their work place, and aggregated over the close surroundings of these locations. In addition, total exposure is accumulated over daily activity patterns, summing exposure at home, at the work place, and while travelling between home and workplace, by routing individuals over the Dutch road network, using the shortest route. Finally, we illustrate how routes can be calculated with the minimum total exposure (instead of shortest distance).

  16. A reassessment of risk associated with dietary intake of ochratoxin A based on a lifetime exposure model.

    PubMed

    Haighton, Lois A; Lynch, Barry S; Magnuson, Bernadene A; Nestmann, Earle R

    2012-02-01

    Mycotoxins, such as ochratoxin A (OTA), can occur from fungal growth on foods. OTA is considered a possible risk factor for adverse renal effects in humans based on renal tumors in male rats. For risk mitigation, Health Canada proposed maximum limits (MLs) for OTA based largely on a comparative risk assessment conducted by Health Canada (Kuiper-Goodman et al., 2010), in which analytical data of OTA in foods were used to determine the possible impact adopting MLs may have on OTA risks. The EU MLs were used for comparison and resultant risk was determined based on age-sex strata groups. These data were reevaluated here to determine comparative risk on a lifetime basis instead of age strata. Also, as there is scientific disagreement over the mechanism of OTA-induced renal tumors, mechanistic data were revisited. On a lifetime basis, risks associated with dietary exposure were found to be negligible, even without MLs, with dietary exposures to OTA three to four orders of magnitude below the pivotal animal LOAEL and the TD(05). Our review of the mechanistic data supported a threshold-based mechanism as the most plausible. In particular, OTA was negative in genotoxicity assays with the highest specificity and levels of DNA adducts were very low and not typical of genotoxic carcinogens. In conclusion, OTA exposures from Canadian foods do not present a significant cancer risk. PMID:22276591

  17. A reassessment of risk associated with dietary intake of ochratoxin A based on a lifetime exposure model

    PubMed Central

    Haighton, Lois A; Lynch, Barry S; Magnuson, Bernadene A; Nestmann, Earle R

    2012-01-01

    Mycotoxins, such as ochratoxin A (OTA), can occur from fungal growth on foods. OTA is considered a possible risk factor for adverse renal effects in humans based on renal tumors in male rats. For risk mitigation. Health Canada proposed maximum limits (MLs) for OTA based largely on a comparative risk assessment conducted by Health Canada (Kuiper-Goodman et al., 2010), in which analytical data of OTA in foods were used to determine the possible impact adopting MLs may have on OTA risks. The EU MLs were used for comparison and resultant risk was determined based on age–sex strata groups. These data were reevaluated here to determine comparative risk on a lifetime basis instead of age strata. Also, as there is scientific disagreement over the mechanism of OTA-induced renal tumors, mechanistic data were revisited. On a lifetime basis, risks associated with dietary exposure were found to be negligible, even without MLs, with dietary exposures to OTA three to four orders of magnitude below the pivotal animal LOAEL and the TD05. Our review of the mechanistic data supported a threshold-based mechanism as the most plausible. In particular, OTA was negative in genotoxicity assays with the highest specificity and levels of DNA adducts were very low and not typical of genotoxic carcinogens. In conclusion, OTA exposures from Canadian foods do not present a significant cancer risk. PMID:22276591

  18. The Public Health Exposome: A Population-Based, Exposure Science Approach to Health Disparities Research

    PubMed Central

    Juarez, Paul D.; Matthews-Juarez, Patricia; Hood, Darryl B.; Im, Wansoo; Levine, Robert S.; Kilbourne, Barbara J.; Langston, Michael A.; Al-Hamdan, Mohammad Z.; Crosson, William L.; Estes, Maurice G.; Estes, Sue M.; Agboto, Vincent K.; Robinson, Paul; Wilson, Sacoby; Lichtveld, Maureen Y.

    2014-01-01

    The lack of progress in reducing health disparities suggests that new approaches are needed if we are to achieve meaningful, equitable, and lasting reductions. Current scientific paradigms do not adequately capture the complexity of the relationships between environment, personal health and population level disparities. The public health exposome is presented as a universal exposure tracking framework for integrating complex relationships between exogenous and endogenous exposures across the lifespan from conception to death. It uses a social-ecological framework that builds on the exposome paradigm for conceptualizing how exogenous exposures “get under the skin”. The public health exposome approach has led our team to develop a taxonomy and bioinformatics infrastructure to integrate health outcomes data with thousands of sources of exogenous exposure, organized in four broad domains: natural, built, social, and policy environments. With the input of a transdisciplinary team, we have borrowed and applied the methods, tools and terms from various disciplines to measure the effects of environmental exposures on personal and population health outcomes and disparities, many of which may not manifest until many years later. As is customary with a paradigm shift, this approach has far reaching implications for research methods and design, analytics, community engagement strategies, and research training. PMID:25514145

  19. The public health exposome: a population-based, exposure science approach to health disparities research.

    PubMed

    Juarez, Paul D; Matthews-Juarez, Patricia; Hood, Darryl B; Im, Wansoo; Levine, Robert S; Kilbourne, Barbara J; Langston, Michael A; Al-Hamdan, Mohammad Z; Crosson, William L; Estes, Maurice G; Estes, Sue M; Agboto, Vincent K; Robinson, Paul; Wilson, Sacoby; Lichtveld, Maureen Y

    2014-01-01

    The lack of progress in reducing health disparities suggests that new approaches are needed if we are to achieve meaningful, equitable, and lasting reductions. Current scientific paradigms do not adequately capture the complexity of the relationships between environment, personal health and population level disparities. The public health exposome is presented as a universal exposure tracking framework for integrating complex relationships between exogenous and endogenous exposures across the lifespan from conception to death. It uses a social-ecological framework that builds on the exposome paradigm for conceptualizing how exogenous exposures "get under the skin". The public health exposome approach has led our team to develop a taxonomy and bioinformatics infrastructure to integrate health outcomes data with thousands of sources of exogenous exposure, organized in four broad domains: natural, built, social, and policy environments. With the input of a transdisciplinary team, we have borrowed and applied the methods, tools and terms from various disciplines to measure the effects of environmental exposures on personal and population health outcomes and disparities, many of which may not manifest until many years later. As is customary with a paradigm shift, this approach has far reaching implications for research methods and design, analytics, community engagement strategies, and research training. PMID:25514145

  20. Anaerobic metabolism, gas exchange, and acid-base balance during hypoxic exposure in the channel catfish,Ictalurus punctatus

    Microsoft Academic Search

    Warren W. Burggren; James N. Cameron

    1980-01-01

    Gill ventilation, blood gas and acid-base values, Mo,, Mc.02 and the gas exchange ratio have been measured before, during, and after exposure to hypoxia in the channel catfish, Zctalurus punctatus. Z.punctatus maintains M,,, at control levels to a PI,, as low as 60 mm Hg, through a profound branchial hyperventilation. Concomitantly, however, a lactic acidosis usually develops, indicating a significant