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1

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 ...

2

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

PubMed

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

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

2013-05-01

3

Task-based lead exposures and work site characteristics of bridge surface preparation and painting contractors.  

PubMed

This study of bridge painters working for small contractors in Massachusetts investigated the causes of elevated blood lead levels and assessed their exposure to lead. Bridge work sites were evaluated for a 2-week period during which personal and area air samples and information on work site characteristics and lead abatement methods were gathered. Short-duration personal inhalable samples collected from 18 tasks had geometric means (GM) of 3 microg/m(3) to 7286 microg/m(3). Full-shift, time-weighted average (TWA) inhalable samples (>or=6 hours) collected from selected workers and work sites had GMs of 2 microg/m(3) to 15,704 microg/m(3); 80% of samples exceeded the permissible exposure limit (PEL) of 50 microg/m(3), on average by a factor of 30. Area inhalable samples collected from three locations ranged from 2 microg/m(3) to 40,866 microg/m(3) from inside the containment, 2 microg/m(3) to 471 microug/m(3) from a distance of <6 meters, and 2 microg/m(3) to 121 microg/m(3) from >6 meters from the containment. Seventy nine percent of the area samples from inside the containment exceeded the PEL on average by a factor of 140. Through observations of work site characteristics, opportunities for improving work methods were identified, particularly the institution of engineering controls (which were only occasionally present) and improvement in the design and construction of the containment structure. The high levels of airborne lead exposures indicate a potential for serious exposure hazard for workers and environmental contamination, which can be mitigated through administrative and engineering controls. Although these data were collected over 10 years ago, a 2005 regulatory review by the Occupational Safety and Health Administration (OSHA) of its lead in construction standard reported that elevated lead exposures and blood lead levels, high occurrence of noncompliance with the lead standard, and nonimplementation of newer technology especially among small painting firms employing <10 workers are still widespread. As a result, the findings of this study are still quite germane even a decade after the introduction of the new OSHA standard. PMID:19065390

Virji, M Abbas; Woskie, Susan R; Pepper, Lewis D

2009-02-01

4

Scenario-Based Tasks  

NSDL National Science Digital Library

This page from The Experiential Learning Center provides a number of scenario-based tasks for use in the classroom or for professional development training. The materials are freely available for download and use and would be applicable to learners in a variety of subjects including software development, faculty professional development, office system applications/ICT, biology/bioinformatics, environmental studies, Python programming, engineering, network security/MIS, computational thinking and English writing. Instructor guides and other classroom instructional materials are provided. The project requests that educators let them know when these materials are used in order to track dissemination of the work and in order to inform the community about upcoming workshops and presentations.

5

Hexavalent chromium exposure and control in welding tasks.  

PubMed

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

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

2010-11-01

6

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

PubMed Central

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

2010-01-01

7

Accuracy of task recall for epidemiological exposure assessment to construction noise  

PubMed Central

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

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

2004-01-01

8

Masonry: Task Analyses. Competency-Based Education.  

ERIC Educational Resources Information Center

These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the masonry program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary courses Masonry…

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

9

Behavior-Based Segmentation of Demonstrated Tasks  

Microsoft Academic Search

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

Nathan Koenig

10

NHP spectral sensitivity metric derived from acute laser exposure effects on pursuit motor tracking task  

NASA Astrophysics Data System (ADS)

Intact retinal function provides the visual guidance component for visual motor performance tasks. Laser induced damage to the retina can degrade visual motor performance by limiting the normal retinal input to the motor system for visual motor guidance. Unlike tasks that are based strictly on the availability of normal visual function, visual motor performance may provide a lesser degree of diagnostic evidence of laser induced visual dysfunction in the presence of significant retinal damage. In order to more exactly track the extent of laser induced retinal damage, we have incorporated measurements of spectral sensitivity derived from a Non-Human Primate (NHP) visual pursuit motor tracking task and derived cone spectral sensitivity functions with peaks consistent with NHP cone photoreceptor spectral sensitivity functions. The reciprocal threshold energy levels for each of nine spectral points in the visible spectrum were determined and energy normalized with respect to the maximum energy. Pre-exposure spectral sensitivity functions revealed spectral peaks in regions comparable to the trichromatic cone photoreceptor system peaks. Post exposure spectral sensitivity measurements at exposure levels 2 log units below the retinal damage threshold revealed transient changes in the shape of the peaks in the post exposure spectral sensitivity that persisted up to 4 weeks post exposure. These effects are linked with transient retinal cone dysfunction and possibly with long term neural adaptive mechanisms.

Zwick, H.; Edsall, P.; Jenkins, K.; Cunningham, R.; Stuck, B. E.

2007-02-01

11

Task-specific monitoring of nuclear medicine technologists' radiation exposure.  

PubMed

Many studies have demonstrated that the exposure of nuclear medicine technologists arises primarily from radioactive patients rather than from preparation of radiopharmaceuticals. However, in order to devise strategies to reduce staff exposure, it is necessary to identify the specific tasks within each procedure that result in the highest radiation doses. An ESM Eberline FH41B-10 radiation dosemeter, which records the ambient dose equivalent rate, was used to monitor the radiation exposure of a technologist and to record the dose rate in microSv per hour every 32 s throughout a working day. The technologist recorded the procedures that were being performed so that the procedures that resulted in higher doses could be identified clearly. The measured doses clearly showed that the major contributions to the technologist's dose were the following: (1) transferring incapacitated patients from the imaging table to a hospital trolley; (2) difficult injections without syringe shields; and (3) setting up patients for gated myocardial scans. The average dose to the technologist from transferring patients after a bone scan was 0.54 microSv, 40% of the total dose of 1.3 microSv for the complete bone scan procedure. The average dose received injecting 900 MBq of 99Tcm-HDP using a tungsten syringe shield was 0.57microSv, but the highest dose was 1.6 microSv, in a patient in whom the injection was difficult. A 0.5 mm lead apron was found to reduce the dose when setting up a patient for a gated stress 99Tcm-sestamibi myocardial scan by approximately a factor of 2. The average dose per patient for this task was reduced from 1.1 to 0.6 microSv. It is recommended that staff waiting for assistance with patient transfers stand away from the patient, that tungsten syringe shields be used for all radiopharmaceutical injections and that a 0.5 mm lead apron be worn when attending patients containing high activities of 99Tcm radiopharmaceuticals, such as those having myocardial imaging. PMID:15254324

Smart, Richard

2004-01-01

12

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

13

TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA  

SciTech Connect

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

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

14

Task simulation in computer-based training  

SciTech Connect

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.

Gardner, P.R.

1988-02-01

15

Worker Lead Exposures During Renovation of Homes with Lead-Based Paint  

Microsoft Academic Search

We evaluated lead exposures among full-time home renovators and part-time volunteers working primarily in pre-1960 homes with lead-based paint. Potentially hazardous lead exposures were measured during two tasks: exterior dry scraping and wet scraping. Maximum exposures were 120 and 63 ?g\\/m, respectively. Exposures during other tasks, including general repair, weatherization, exterior scraping\\/painting (mostly applying new paint), window replacement, demolition, and

Aaron Sussell; Janie Gittleman; Mitchell Singal

1998-01-01

16

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

PubMed Central

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

2009-01-01

17

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

ERIC Educational Resources Information Center

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

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

18

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

SciTech Connect

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.

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

19

Characterizing Task-Based OpenMP Programs.  

PubMed

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

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

2015-01-01

20

Characterizing Task-Based OpenMP Programs  

PubMed Central

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

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

2015-01-01

21

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

PubMed Central

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

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

2014-01-01

22

Applications of Task-Based Learning in TESOL  

ERIC Educational Resources Information Center

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…

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

2010-01-01

23

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

PubMed

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

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

2012-07-01

24

Critical working tasks and determinants of exposure to bioaerosols and MVOC at composting facilities.  

PubMed

Airborne bioaerosols and Microbial Volatile Organic Compounds (MVOC) concentrations were simultaneously monitored at a composting facility and the main determinants of atmospheric concentrations were characterised, in order to help protect workers from potential adverse health effects. Microorganisms and MVOC were sampled during various process stages and working tasks, both on site at the two units (green waste and biowaste), and at the border of the composting facility. Ambient monitorings were performed at sampling points deemed representative of occupational exposures for critical working tasks, and additional individual samplings were done on workers for MVOC. A linear regression model was used to estimate the determinants explaining exposure variability to bioaerosols and volatile compounds. Bioaerosol concentrations ranging from 10(2) to 1.8x10(5)cfu/m(3) were observed, with peak exposures in the shredding and waste sieving phases. Shredder and siever adjustments, cleaning and maintenance of aeration systems/composting containers were associated with the highest bioaerosols ambient concentrations. MVOC concentration profiles were highly variable depending on the composting unit. Shredding/rotting phases were associated with the highest levels at respectively green waste/biowaste units. Terpenoids and alcohols were the most predominant compounds, and total MVOC levels reached up to 40mg/m(3). Individual and ambient MVOC concentrations did not show significant differences. "Season", "waste turning", "process stage" and "sampling location" were the main determinants of bioaerosols and MVOC concentrations variability. Moderate or no correlation was found between microorganisms and volatile organic compounds concentrations. The high bioaerosol and MVOC levels observed as well as the potential of additive irritative effects resulting from these exposures justify the wearing of personal protective equipments for the associated working tasks. On the other hand, low concentrations recorded in the immediate vicinity of the facility suggested a limited environmental impact from the composting activity. Simultaneous monitoring of bioaerosols and MVOC exposures at various sampling locations and during main working tasks (including cleaning/maintenance tasks) seems of importance for improving health risk assessments at composting facilities. PMID:20619730

Persoons, Renaud; Parat, Sylvie; Stoklov, Muriel; Perdrix, Alain; Maitre, Anne

2010-09-01

25

An Agent-Based Cockpit Task Management System  

NASA Technical Reports Server (NTRS)

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

Funk, Ken

1997-01-01

26

Task Allocation Using a Distributed Market-Based Planning Mechanism  

E-print Network

as they see fit. Conspicuously absent from the market approach is a rigid, top-down hierarchy. InsteadTask Allocation Using a Distributed Market-Based Planning Mechanism Dani Goldberg, Vincent,cicirello,mbdias,reids,sfs,axs}@cs.cmu.edu ABSTRACT This paper describes a market-based planning mechanism used for task and resource allocation

Cicirello, Vincent A.

27

Designing Digital Problem Based Learning Tasks that Motivate Students  

ERIC Educational Resources Information Center

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

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

2013-01-01

28

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

ERIC Educational Resources Information Center

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

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

29

Vietnamese Children and Language-Based Processing Tasks  

ERIC Educational Resources Information Center

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…

Hwa-Froelich, Deborah A.; Matsuo, Hisako

2005-01-01

30

TASK-BASED INTERFACES FOR DECENTRALIZED MULTIPLE UNMANNED VEHICLE CONTROL  

E-print Network

be robust to task load increases by mitigat- ing operator cognitive overload. INTRODUCTION A future concept to operator cognitive overload and performance degradation.13, 14 To address this concern, we seek to leverage task-based interfaces, where the human operator * Doctoral Student, MIT Aeronautics and Astronautics

Cummings, Mary "Missy"

31

Critical Task Characteristics in Problem-Based Learning  

ERIC Educational Resources Information Center

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…

Otting, Hans; Zwaal, Wichard

2006-01-01

32

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

ERIC Educational Resources Information Center

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…

Georgia State Univ., Atlanta. School of Education.

33

Consensus-based auctions for decentralized task assignment  

E-print Network

This thesis addresses the decentralized task assignment problem in cooperative autonomous search and track missions by presenting the Consensus-Based class of assignment algorithms. These algorithm make use of information ...

Brunet, Luc (Luc P. V.)

2008-01-01

34

A Task-Based Approach to Adaptive and Multimodality Imaging  

PubMed Central

Multimodality imaging is becoming increasingly important in medical imaging. Since the motivation for combining multiple imaging modalities is generally to improve diagnostic or prognostic accuracy, the benefits of multimodality imaging cannot be assessed through the display of example images. Instead, we must use objective, task-based measures of image quality to draw valid conclusions about system performance. In this paper, we will present a general framework for utilizing objective, task-based measures of image quality in assessing multimodality and adaptive imaging systems. We introduce a classification scheme for multimodality and adaptive imaging systems and provide a mathematical description of the imaging chain along with block diagrams to provide a visual illustration. We show that the task-based methodology developed for evaluating single-modality imaging can be applied, with minor modifications, to multimodality and adaptive imaging. We discuss strategies for practical implementing of task-based methods to assess and optimize multimodality imaging systems. PMID:19079563

Clarkson, Eric; Kupinski, Matthew A.; Barrett, Harrison H.; Furenlid, Lars

2008-01-01

35

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...

36

Exposure to Repetitive Tasks Induces Motor Changes Related to Skill Acquisition and Inflammation in Rats  

PubMed Central

This study elucidates exposure-response relationships between repetitive tasks, inflammation and motor changes with work-related musculoskeletal disorders. Using a rat model of reaching and handle-pulling, we examined effects of performing a high repetition low force (HRLF), low repetition high force (LRHF), or high repetition high force (HRHF) task (2 h/day, 3 days/wk, 12 wks) on reach rate and force, percent success, duration of participation and grip strength. Reach rate and reach force improved with HRLF, and percent success increased in all groups in week 9, and HRLF and HRHF in week 12, indicative of skill acquisition. Duration and grip strength showed force-dependent declines with task performance. A subset of HRHF rats received ibuprofen in weeks 5–12. Ibuprofen significantly improved reach rate, reach force and duration in treated rats, indicative of an inflammatory influence on reach performance. Ibuprofen improved percent successful reaches in week 9, although this increase was not sustained. However, declines in grip strength, a nocifensive behavior, were not prevented by ibuprofen. Examination of cervical spinal cords of untreated and ibuprofen treated HRHF rats showed increased IL-1beta, an inflammatory cytokine, in neurons. These findings suggest that only a preventive intervention could have addressed all motor declines. PMID:22087754

Kietrys, David M.; Barr, Ann E; Barbe, Mary F

2013-01-01

37

Task-Based Flocking Algorithm for Mobile Robot Cooperation  

NASA Astrophysics Data System (ADS)

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

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

38

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

ERIC Educational Resources Information Center

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

Plews, John L.; Zhao, Kangxian

2010-01-01

39

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...

40

Age-Based Differences in Strategy Use in Choice Tasks  

PubMed Central

We incorporated behavioral and computational modeling techniques to examine age-based differences in strategy use in two four-choice decision-making tasks. Healthy older (aged 60–82?years) and younger adults (aged 18–23?years) performed one of two decision-making tasks that differed in the degree to which rewards for each option depended on the choices made on previous trials. In the choice-independent task rewards for each choice were not affected by the sequence of previous choices that had been made. In contrast, in the choice-dependent task rewards for each option were based on how often each option had been chosen in the past. We compared the fits of a model that assumes the use of a win-stay–lose-shift (WSLS) heuristic to make decisions, to the fits of a reinforcement-learning (RL) model that compared expected reward values for each option to make decisions. Younger adults were best fit by the RL model, while older adults showed significantly more evidence of being best fit by the WSLS heuristic model. This led older adults to perform worse than younger adults in the choice-independent task, but better in the choice-dependent task. These results coincide with previous work in our labs that also found better performance for older adults in choice-dependent tasks (Worthy et al., 2011), and the present results suggest that qualitative age-based differences in the strategies used in choice tasks may underlie older adults’ advantage in choice-dependent tasks. We discuss possible factors behind these differences such as neurobiological changes associated with aging, and increased use of heuristics by older adults. PMID:22232573

Worthy, Darrell A.; Maddox, W. Todd

2012-01-01

41

Agile Team Learning Model Based on Fast Task Mining  

Microsoft Academic Search

\\u000a Team learning needs explicit shared task and certain environment. In this paper, we presents an agile team learning model\\u000a based on fast task mining (ATLM) that can be used with network environment and without more guidance. This model can improve\\u000a the precision of knowledge acquisition and shorten the learning period. The learning process presented in ATLM can be applied\\u000a in

Xiaobo Yin; Guangli Zhu; Li Feng

2010-01-01

42

'Stoffenmanager', a web-based control banding tool using an exposure process model.  

PubMed

In the scope of a Dutch programme to reinforce the working conditions policy on hazardous substances, an internet-based tool was developed to help small- and medium-sized companies to handle hazardous substances with more care. The heart of this tool, called the Stoffenmanager, is a risk banding scheme. It combines a hazard banding scheme similar to that of COSHH Essentials and an exposure banding scheme based on an exposure model originally presented by Cherrie et al. (1996) and further developed by Cherrie and Schneider (1999). The exposure model has been modified to allow non-expert users to understand and use the model. Exposure scores are calculated based on categorization of determinants of emission, transmission and immission. These exposure scores are assigned to exposure bands. The comparison of exposure bands and hazard bands leads to a risk band or priority band. Following the evaluation of the priority of tasks done with products, generic exposure control measures can be evaluated for their possibility to lower the risks. Relevant control measures can be put into an action plan and into workplace instruction cards. The tool has several other functionalities regarding registration and storage of products. The exposure model in the Stoffenmanager leads to exposure scores. These have been compared with measured exposure levels. The exposure scores correlated well with measured exposure levels. The development of the Stoffenmanager has facilitated a whole range of further developments of useful tools for small- and medium-sized enterprises. PMID:18587140

Marquart, Hans; Heussen, Henri; Le Feber, Maaike; Noy, Dook; Tielemans, Erik; Schinkel, Jody; West, John; Van Der Schaaf, Doeke

2008-08-01

43

Task-based working memory guidance of visual attention.  

PubMed

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

Chen, Zhe; Tsou, Brian H

2011-05-01

44

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

SciTech Connect

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.

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

45

EFL Reading Instruction: Communicative Task-Based Approach  

ERIC Educational Resources Information Center

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

Sidek, Harison Mohd

2012-01-01

46

Hybrid Heuristic-Based Artificial Immune System for Task Scheduling  

E-print Network

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...

sanei, Masoomeh

2011-01-01

47

Worker lead exposures during renovation of homes with lead-based paint  

SciTech Connect

The authors evaluated lead exposures among full-time home renovators and part-time volunteers working primarily in pre-1960 homes with lead-based paint. Potentially hazardous lead exposures were measured during two tasks: exterior dry scraping and wet scraping. Maximum exposures were 120 and 63 {micro}g/m{sup 3}, respectively. Exposures during other tasks, including general repair, weatherization, exterior scraping/painting, window replacement, demolition, and plumbing, were low, as were all 13 full-shift personal exposures. Blood lead levels for full-time workers ranged up to 17.5 {micro}g/dl, with a GM of 5.2 {micro}g/dl; the GM for volunteers was 3.2 {micro}g/dl. All of the paint samples collected from work surfaces had detectable amounts of lead, with 65% of the work surfaces tested having an average lead concentration of >0.5%.

Sussell, A.; Gittleman, J.; Singal, M. [National Inst. for Occupational Safety and Health, Cincinnati, OH (United States)

1998-11-01

48

An ontology-based telemedicine tasks management system architecture.  

PubMed

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

Nageba, Ebrahim; Fayn, Jocelyne; Rubel, Paul

2008-01-01

49

Children's Creative Collaboration during a Computer-Based Music Task  

ERIC Educational Resources Information Center

The purpose of this study was to identify and analyse specific instances of transactive communication as children engaged in a paired melody writing task using a computer-based composing environment. Transactive communication has been identified as one of the features of general collaborative engagement that is most helpful in an educational…

Hewitt, Allan

2008-01-01

50

Task-Based Language Teaching and Expansive Learning Theory  

ERIC Educational Resources Information Center

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…

Robertson, Margaret

2014-01-01

51

Strategy Training in a Task-Based Language Classroom  

ERIC Educational Resources Information Center

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

Lai, Chun; Lin, Xiaolin

2015-01-01

52

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

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

53

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

54

Exposure-based treatment to control excessive blood glucose monitoring  

Microsoft Academic Search

We investigated an exposure-based procedure for reducing excessive checking of blood glucose by a child with diabetes. In a changing criterion design, an exposure-based pro- cedure was implemented by systematically exposing the child to decreasing amounts of information about blood sugar levels (checking) and thereby increasing exposure to po- tential hypoglycemia. Access to information was reduced in graduated increments, with

KEITH D. ALLEN; JOSEPH H. EVANS

2001-01-01

55

Depressive rumination and experiential avoidance: A task based exploration.  

PubMed

Depressive rumination has been conceptualized as being closely connected with experiential avoidance. Evidence supporting this hypothesis derives primarily from studies using self-report measures. The present study explores this idea using a task-based assessment of avoidance. College students (N?=?100) rated their emotional responses to 60 computer-presented images (positive, negative and neutral). Response times for the image-rating task were surreptitiously recorded, along with Ruminative Response Scale and Beck Depression Inventory II scores. Rumination was correlated with faster response times for negative, but not positive or neutral images. These findings are interpreted as lending support to the experiential avoidance conceptualization of rumination; however, consideration is also given to a potentially synergistic interpretation implicating heightened threat monitoring. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25273612

Thomas, Justin; Raynor, Monique; Ribott, David

2015-02-01

56

Emotion-based learning: insights from the Iowa Gambling Task  

PubMed Central

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

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

2014-01-01

57

Task-based lens design with application to digital mammography  

PubMed Central

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

Chen, Liying; Barrett, Harrison H.

2006-01-01

58

Requirements Elicitation and Elaboration in Task-Based Design Needs More Than Task Modelling: A Case Study  

Microsoft Academic Search

In this paper, a small case study is presented to illustrate our conceptual understanding of a task-based requirements process.\\u000a We argue that sub-models as known in model-based design (e.g. task models, dialog models) support the reflection about an\\u000a existing work situation at a conceptual level and allow a formal specification of requirements. However, it is also shown\\u000a that the integration

Anke Dittmar; Andreas Gellendin; Peter Forbrig

2006-01-01

59

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

PubMed Central

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

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

2014-01-01

60

Gaze-based prediction of pen-based virtual interaction tasks$ , Tevfik Metin Sezgin  

E-print Network

Gaze-based prediction of pen-based virtual interaction tasks$ Çala Çi n , Tevfik Metin Sezgin interface elements. Recently, pen- based interaction has emerged as a more intuitive alternative to these traditional means. However, existing pen-based systems are limited by the fact that they rely heavily

Sezgin, Metin

61

The behavioral avoidance task using imaginal exposure (BATIE): a paper-and-pencil version of traditional in vivo behavioral avoidance tasks.  

PubMed

Behavioral avoidance tasks (BATs) have been used for decades in the assessment of specific phobias, but they also involve a number of prohibitive difficulties. This study investigated a new imaginal/self-report instrument, the Behavioral Avoidance Task Using Imaginal Exposure (BATIE), and evaluated whether it was an efficient paper-and-pencil alternative. Forty-nine adults diagnosed with specific phobias were matched to 49 participants without those particular phobias who served as control participants. The participants were 89.8% female and 79.6% Caucasian and had a mean age of 20.81 years (SD = 3.62). Diagnosis was determined using the Anxiety Disorders Interview Schedule (Brown, DiNardo, & Barlow, 1994). Participants completed a BAT following a BATIE. Results indicated BATIE ratings significantly correlated with BAT performance and ratings. Significant differences were also found between the phobic and control groups on all BATIE ratings (all differences indicated poorer performance or more fear in those with specific phobias). Also, the BATIE scores demonstrated good evidence of convergent and discriminant validity compared to other self-reports, significantly predicted BAT performance even when controlling for those measures of fear and anxiety, and significantly predicted diagnostic severity ratings. Overall, results indicated that the BATIE may be a reasonable alternative to in vivo BATs in certain situations (e.g., clinical practice, unavailability of BAT stimuli). PMID:23730830

Davis, Thompson E; Reuther, Erin T; May, Anna C; Rudy, Brittany M; Munson, Melissa S; Jenkins, Whitney S; Whiting, Sara E

2013-12-01

62

Repeating Input-Based Tasks with Young Beginner Learners  

ERIC Educational Resources Information Center

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

Shintani, Natsuko

2012-01-01

63

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

ERIC Educational Resources Information Center

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…

Pellerin, Martine

2014-01-01

64

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

PubMed

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

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

65

Creative Disruption: A Task-Based Approach to Engaging With Original Works of Art  

ERIC Educational Resources Information Center

This paper examines the value of a task-based approach to engaging with original works of art and focuses in particular upon the experiences of a group of PGCE Art and Design trainees when they visited an exhibition entitled, Air Guitar: Art Reconsidering Rock Music, to carry out given tasks. The extent to which a task-based approach might…

Walker, Keith; Smith, Liz

2004-01-01

66

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

E-print Network

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...

Comer, William J.

2007-01-01

67

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

PubMed Central

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

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

2011-01-01

68

Prenatal Cocaine\\/Polydrug Exposure and Infant Performance on an Executive Functioning Task  

Microsoft Academic Search

Executive functioning in cocaine\\/polydrug (marijuana, alcohol, tobacco) exposed infants was assessed in a single session, occurring between 9.5 and 12.5 months of age. In an A-not-B task, infants searched, after performance-adjusted delays, for an object hidden in a new location. Overall, the cocaine-exposed (CE) infants did not differ from non-CE controls recruited from the same at-risk population. However, comparison of

Julia S. Noland; Lynn T. Singer; Sudhir K. Mehta; Dennis M. Super

2003-01-01

69

Implementing Authentic Tasks in Web-Based Learning Environments  

ERIC Educational Resources Information Center

The use of authentic tasks is derived from social constructivist principles of locating learning in the context of reality. Authentic tasks can foster learning transfer because collaboration among students not only helps them learn the concepts under discussion, but also exemplifies how these concepts are used in real-world contexts. To achieve a…

Woo, Younghee; Herrington, Jan; Agostinho, Shirley; Reeves, Thomas C.

2007-01-01

70

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

PubMed

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

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

2011-01-01

71

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

ERIC Educational Resources Information Center

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

O'Connell, Stephen P.

2014-01-01

72

A task-based quality control metric for digital mammography.  

PubMed

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

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

2014-11-01

73

A task-based quality control metric for digital mammography  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

74

The application of a task-based concept for the design of innovative industrial crystallizers  

Microsoft Academic Search

A new task-based design approach [Menon, A. R., Pande, A. A., Kramer, H. J. M., Grievink, J., & Jansens, P. J. (2007). A task-based synthesis approach toward the design of industrial crystallization process units. Industrial & Engineering Chemistry Research, 46, 3979] is applied to design a crystallization process unit. Task-based design involves the conceptual built-up of a process (unit) from

Richard Lakerveld; Herman J. M. Kramer; Peter J. Jansens; Johan Grievink

2009-01-01

75

Tournament based task allocation in a parallel MIS algorithm  

E-print Network

This paper explores the use of a tournament data structure for task allocation and dependency tracking in a parallel Maximal Independent Set (MIS) algorithm as a way to reduce contention in counter updates and improve ...

Ezeaka, Chidubem L

2014-01-01

76

Assessment of occupational exposure in a population based case-control study: comparing postal questionnaires with personal interviews.  

PubMed Central

BACKGROUND: In case-control studies, data collection on occupational exposures by means of personal interviews is usually costly and time consuming. As detailed semiquantitative information on exposure from these interviews often has to be dichotomised in the analyses due to the small numbers of exposed subjects, the question is raised whether simple postal questionnaires yield the same results for occupational exposure in epidemiological studies as job specific personal interviews. METHODS: Data on occupational exposures during pregnancy were compared from 121 women who both completed a checklist with 17 occupational exposure categories in a postal questionnaire and were personally interviewed with specific questions on exposure with details of job and task. kappa Coefficients were calculated as measures of agreement corrected for chance, and sensitivity and positive predictive values as measures of validity and usefulness, with the exposure assessment based on information from the interview as the gold standard. RESULTS: Values of kappa varied from 0.09 for domestic cleaning agents to 0.70 for pesticides, indicating only low to moderate agreement between the questionnaire and the interview. Sensitivity ranged from 38% to 100%, with the highest values for agents used by healthcare workers. Positive predictive values were lower, between 9% and 63%, which indicates that overreporting was more common than underreporting in the questionnaire. CONCLUSIONS: These results underline the high potential for misclassification of occupational exposure in studies based on questionnaires. Therefore, postal questionnaires are not considered an alternative to job and task specific personal interviews in epidemiological studies. PMID:9072035

Blatter, B M; Roeleveld, N; Zielhuis, G A; Verbeek, A L

1997-01-01

77

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

PubMed Central

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

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

2014-01-01

78

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

PubMed

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

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

2014-01-01

79

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

80

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

PubMed

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

Khanna, Maya M

2015-01-01

81

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

NASA Technical Reports Server (NTRS)

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

Hutchinson, R. R.

1975-01-01

82

Assembly and task planning in a collaborative web-based environment based on assembly process modeling methodology  

Microsoft Academic Search

Assembly task planning is the generation of the ordered sequence of tasks necessary to assembly the given parts. Based on the Assembly Process Modeling Methodology (APM) developed at the Assembly Automation Laboratory, where the product definition includes both logical and physical building blocks, and the dependencies between them, the development of an Intelligent Task Planning system built upon a Collaborative

R. V. Osuna; T. Tallinen; J. L. M. Lastra; R. Tuokko

2003-01-01

83

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

NASA Astrophysics Data System (ADS)

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.

Takenouchi, Takashi; Komori, Osamu; Eguchi, Shinto

2015-01-01

84

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

ERIC Educational Resources Information Center

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

Collentine, Karina

2009-01-01

85

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

ERIC Educational Resources Information Center

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

Pyun, Danielle Ooyoung

2013-01-01

86

Trayectorias: A New Model for Online Task-Based Learning  

ERIC Educational Resources Information Center

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

Ros i Sole, Cristina; Mardomingo, Raquel

2004-01-01

87

Market-based Multirobot Coordination for Complex Tasks  

Microsoft Academic Search

Current technological developments and application-driven demands are bringing us closer to the realization of au- tonomous multirobot systems performing increasingly com- plex missions. However, existing methods of distributing mis- sion subcomponents among multirobot teams do not explicitly handle the required complexity and instead treat tasks as sim- ple indivisible entities, ignoring any inherent structure and se- mantics that such complex

Robert Zlot; Anthony Stentz

2006-01-01

88

Task Templates Based on Misconception Research. CSE Report 646.  

ERIC Educational Resources Information Center

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

Cromley, Jennifer G.; Mislevy, Robert J.

2004-01-01

89

Design and Analysis in Task-Based Language Assessment.  

ERIC Educational Resources Information Center

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

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

2002-01-01

90

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

PubMed Central

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

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

2014-01-01

91

Development of Prospective Memory: Tasks Based on the Prefrontal-Lobe Model  

Microsoft Academic Search

This study investigated the development of prospective memory using tasks based on the prefrontal-lobe model. Three groups each of 30 children, adolescents, and young adults were compared on prospective-memory performance using ongoing tasks with two levels of cognitive demand (low and high), and two levels of importance (unstressed and stressed) of remembering prospective cues. The Self-Ordered Pointing Task (SOPT), Stroop

Heather Ward; David Shum; Lynne McKinlay; Simone Baker-Tweney; Geoff Wallace

2005-01-01

92

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

PubMed

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

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

2000-03-01

93

Task-based evaluation of meeting browsers: from task elicitation to user behavior analysis  

E-print Network

recordings, e.g. a series of corporate meetings that were captured in an instrumented meeting room. The goal features of the Transcript-based Query and Browsing interface (TQB), an annotation-oriented meeting browser satisfaction ­ measured using questionnaires. A well-known approach to dialogue sys- tem evaluation, PARADISE

94

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

PubMed

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

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

2014-05-01

95

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

ERIC Educational Resources Information Center

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…

Judd, Terry; Kennedy, Gregor

2011-01-01

96

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

E-print Network

Task-Model Based Human Robot Cooperation Using Vision 3 Hiroshi Kimura and Tomoyuki Horiuchi an experiment in which the human and the robotic hand assembled toy parts in cooperation. 1 Introduction in a cooperative task. In order to assist the hu- man, a robot must autonomously recognize the human motion in real

Kimura, Hiroshi

97

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

ERIC Educational Resources Information Center

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

Leung, Allen; Lee, Arthur Man Sang

2013-01-01

98

Input-Based Tasks and the Acquisition of Vocabulary and Grammar: A Process-Product Study  

ERIC Educational Resources Information Center

The study reported in this article investigated the use of input-based tasks with young, beginner learners of English as a second language by examining both learning outcomes (i.e. acquisition) and the interactions that resulted from implementing the tasks. The participants were 15 learners, aged six, with no experience of second language (L2)…

Shintani, Natsuko

2012-01-01

99

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

ERIC Educational Resources Information Center

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…

Fiester, Herbert R.

2010-01-01

100

A learning automata based framework for task assignment in heterogeneous computing systems  

Microsoft Academic Search

In this paper, a framework for task assignment in hetero- geneous computing (HC) systems is presented. This frame- work is based on a learning automata model. The proposed model can be used for dynamic task assignment and schedul- ing and can adapt itself to changes in the hardware or net- work environment. An important feature of this framework is that

Raju D. Venkataramana; N. Ranganathan

1999-01-01

101

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

NASA Astrophysics Data System (ADS)

Digital breast tomosynthesis (DBT) is a novel x-ray imaging technique that provides 3D structural information of the breast. In contrast to 2D mammography, DBT minimizes tissue overlap potentially improving cancer detection and reducing number of unnecessary recalls. The addition of a contrast agent to DBT and mammography for lesion enhancement has the benefit of providing functional information of a lesion, as lesion contrast uptake and washout patterns may help differentiate between benign and malignant tumors. This study used a task-based method to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: contrast enhanced mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Imaging performance was characterized using a detectability index d', derived from the system task transfer function (TTF), an imaging task, iodine contrast, and the noise power spectrum (NPS). The task modeled a 5 mm lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d' was generated as a function of dose and iodine concentration. In general, higher dose gave higher d', but for the lowest iodine concentration and lowest dose, dual energy subtraction tomosynthesis and temporal subtraction tomosynthesis demonstrated the highest performance.

Ikejimba, Lynda; Kiarashi, Nooshin; Lin, Yuan; Chen, Baiyu; Ghate, Sujata V.; Zerhouni, Moustafa; Samei, Ehsan; Lo, Joseph Y.

2012-03-01

102

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

103

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

PubMed Central

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

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

2012-01-01

104

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

105

A Decision Analytic Approach to Exposure-Based Chemical Prioritization  

PubMed Central

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

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

2013-01-01

106

Return-based style analysis with time-varying exposures  

Microsoft Academic Search

This paper focuses on the estimation of mutual fund styles by return-based style analysis. Often the investment style is assumed to be constant through time. Alternatively, time variation is sometimes implicitly accounted for by using rolling regressions when estimating the style exposures. The former assumption is often contradicted empirically, and the latter is inefficient due to its ad hoc chosen

Laurens Swinkels; Pieter J. Van Der Sluis

2006-01-01

107

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

NASA Technical Reports Server (NTRS)

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

1987-01-01

108

Refining the Construct of Classroom-Based Writing-from-Readings Assessment: The Role of Task Representation  

ERIC Educational Resources Information Center

This article argues that task representation should be considered as part of the construct of classroom-based academic writing. Task representation is a process that writers move through when creating a unique mental model of the requirements for each new writing task they encounter. Writers' task representations evolve throughout the composing…

Wolfersberger, Mark

2013-01-01

109

Effects of a Classroom-Based Program on Physical Activity and On-Task Behavior  

Microsoft Academic Search

MAHAR, M. T., S. K. MURPHY, D. A. ROWE, J. GOLDEN, A. T. SHIELDS, and T. D. RAEDEKE. Effects of a Classroom-Based Program on Physical Activity and On-Task Behavior. Med. Sci. Sports Exerc., Vol. 38, No. 12, pp. 2086Y2094, 2006. Purpose: This study evaluated the effects of a classroom-based physical activity program on childrens in-school physical activity levels and on-task

MATTHEW T. MAHAR; SHEILA K. MURPHY; DAVID A. ROWE; JEANNIE GOLDEN; A. TAMLYN SHIELDS; THOMAS D. RAEDEKE

2006-01-01

110

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

Microsoft Academic Search

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.

Danny Weyns; Nelis Boucké; Tom Holvoet

2008-01-01

111

Multi-robot task allocation based on two dimensional artificial fish swarm algorithm  

NASA Astrophysics Data System (ADS)

The problem of task allocation for multiple robots is to allocate more relative-tasks to less relative-robots so as to minimize the processing time of these tasks. In order to get optimal multi-robot task allocation scheme, a twodimensional artificial swarm algorithm based approach is proposed in this paper. In this approach, the normal artificial fish is extended to be two dimension artificial fish. In the two dimension artificial fish, each vector of primary artificial fish is extended to be an m-dimensional vector. Thus, each vector can express a group of tasks. By redefining the distance between artificial fish and the center of artificial fish, the behavior of two dimension fish is designed and the task allocation algorithm based on two dimension artificial swarm algorithm is put forward. At last, the proposed algorithm is applied to the problem of multi-robot task allocation and comparer with GA and SA based algorithm is done. Simulation and compare result shows the proposed algorithm is effective.

Zheng, Taixiong; Li, Xueqin; Yang, Liangyi

2007-12-01

112

Physiologically based pharmacokinetic modelling of human exposure to 2-butoxyethanol.  

PubMed

A physiologically based pharmacokinetic (PBPK) model describing the disposition of 2-butoxyethanol (2-BE) was developed in order to predict the urinary concentration of its major metabolite, butoxyacetic acid (BAA) under a range of exposure scenarios. Based on Corley et al. [Corley, R.A., Bormett, G.A., Ghanayem, B.I., 1994. Physiologically based pharmacokinetics of 2-butoxyethanol and its major metabolite, 2-butoxyacetic acid, in rats and humans. Toxicol. Appl. Pharmacol. 129, 61-79], the model included such features as multiple entry routes into the body, varying workload conditions, metabolism in the liver and elimination of free BAA in urine by glomerular filtration and acid transport. A bladder compartment simulating the fluctuations in metabolite concentration in urine caused by micturition formed a novel aspect of the model. Good agreement between model predictions and existing experimental data of total BAA levels in the blood and urine over various exposure conditions were observed. The mechanistically based PBPK model allowed comparison of disparate studies and also enabled the prediction of urinary concentrations of BAA post-shift. By calculating the total amount of BAA, any inter-individual variability in conjugation is taken into account. This led us to conclude that a biological monitoring guidance value should be proposed for total rather than free BAA with a value of 250 mmol/mol of creatinine (post-shift), based on an 8h exposure to 25 ppm 2-BE at resting working conditions. PMID:16246510

Franks, S J; Spendiff, M K; Cocker, J; Loizou, G D

2006-04-10

113

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

PubMed

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

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

2014-01-01

114

Fault-Tolerant Dynamic Task Scheduling Based on Dataflow Graphs  

Microsoft Academic Search

This paper describes a distributed algorithm for scheduling parallel programs represented by (macro-) dataflow graphs on multicomputer systems such that they are executed in a fault-tolerant way. Fault tolerance is based on dynamic redundancy comprising checkpointing, self-diagnosis and rollback recovery. The schedule is computed dynamically during the runtime of the process system. It works in a completely distributed way by

Erik Maehle; Franz-Josef Markus

115

Realization of the Table Tennis Task Based on Virtual Targets  

Microsoft Academic Search

This paper describes how a table tennis robot with a fiat paddle coordinates its movement in order to achieve efficient strokes for any given ball. We pro- pose a method of generating stroke movement based on virtual targets that means the point at which the ball should be struck and the paddle velocity just be- fore hitting the ball. These

Fumio Miyazaki; Takeuchi Michiya Matsushima; Michiya Matsushima; Takamichi Kusano; Takaaki Hashimoto

2002-01-01

116

Behavior-based multi-robot collaboration for autonomous construction tasks  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

117

Performance of Schizophrenia Patients on Time, Event, and Activity-Based Prospective Memory Tasks  

Microsoft Academic Search

The present study aimed to determine whether individ- uals with long-term schizophrenia have impaired prospective memory (PM), the ability to remember to perform intended actions in the future. Three PM tasks (time-, event-, and activity-based) were administered to 60 schizophrenia patients and 60 matched controls. Patients performed significantly more poorly than con- trols on all three tasks. The between-group difference

David Shum; Kwong Tang; Jin Pang Leung

118

Performance of Schizophrenia Patients on Time, Event, and Activity-Based Prospective Memory Tasks  

Microsoft Academic Search

The present study aimed to determine whether individuals with long-term schizophrenia have impaired prospective memory (PM), the ability to remember to perform intended actions in the future. Three PM tasks (time-, event-, and activity-based) were administered to 60 schizophrenia patients and 60 matched controls. Patients performed significantly more poorly than controls on all three tasks. The between-group difference was disproportionately

David Shum; Gabor S. Ungvari; Wai-Kwong Tang; Jin Pang Leung

2004-01-01

119

MPI-Based Adaptive Task Migration Support on the HS-Scale System  

Microsoft Academic Search

Abstract Scalability of architecture, programming model and task control management will be a major challenge for future VLSI systems. In this context, homogeneous MPSOC is a seducing approach,as it ,is intrinsically scalable. ,HS-Scale is a contribution in this ,domain ,and ,was ,already published ,in [1,2]. In this article, we present an original MPI-based adaptive task migration support for the HS-Scale

Nicolas Saint-jean; Pascal Benoit; Gilles Sassatelli; Lionel Torres; Michel Robert

2008-01-01

120

An Agent-Based System Assisting Humans in Complex Tasks by Analysis of a Human's State and Performance  

E-print Network

An Agent-Based System Assisting Humans in Complex Tasks by Analysis of a Human's State, and characteristics of the human. This paper contributes an agent-based system that is an instantiation, michael}@forcevisionlab.nl Abstract Human task performance varies depending on the task, environment

Treur, Jan

121

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

122

Mobile Task Computing: Beyond Location-Based Services and EBooks  

Microsoft Academic Search

\\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),

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

2010-01-01

123

SIMPLIFIED PHYSICS BASED MODELSRESEARCH TOPICAL REPORT ON TASK #2  

SciTech Connect

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.

Mishra, Srikanta; Ganesh, Priya

2014-10-31

124

Alcohol Exposure Rate Control through Physiologically-Based Pharmacokinetic Modeling  

PubMed Central

Background The instantaneous rate of change of alcohol exposure (slope) may contribute to changes in measures of brain function following administration of alcohol that are usually attributed to breath alcohol concentration (BrAC) acting alone. To test this proposition, a 2-session experiment was designed in which carefully-prescribed, constant-slope trajectories of BrAC intersected at the same exposure level and time since the exposure began. This paper presents the methods and limitations of the experimental design. Methods Individualized intravenous infusion rate profiles of 6% ethanol that achieved the constant slope trajectories for an individual were precomputed using a physiologically-based pharmacokinetic model. Adjusting the parameters of the model allowed each infusion profile to account for the subject’s ethanol distribution and elimination kinetics. Sessions were conducted in randomized order and made no use of feedback of BrAC measurements obtained during the session to modify the pre-calculated infusion profiles. In one session, an individual’s time course of exposure, BrAC(t), was prescribed to rise at a constant rate of 6.0 mg% per min until it reached 68 mg% and then descend at ?1.0 mg% per min; in the other, to rise at a rate of 3.0 mg% per min. The 2 exposure trajectories were designed to intersect at a BrAC(t=20 min) = 60 mg% at an experimental time of 20 minutes. Results Intersection points for 54 of 61 subjects were within prescribed deviations (range of ± 3 mg% and ± 4 min from the nominal intersection point. Conclusion Results confirmed the feasibility of the applying the novel methods for achieving the intended time courses of the BrAC, with technical problems limiting success to 90% of the individuals tested. PMID:22486174

Plawecki, Martin H.; Zimmermann, Ulrich S.; Vitvitskiy, Victor; Doerschuk, Peter C.; Crabb, David; O’Connor, Sean

2011-01-01

125

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

ERIC Educational Resources Information Center

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

Smith, Chad E.

2007-01-01

126

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

ERIC Educational Resources Information Center

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…

Gleason, Jesse

2014-01-01

127

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

ERIC Educational Resources Information Center

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…

Houssart, Jenny; Evens, Hilary

2011-01-01

128

Exploring Vision-Based Interfaces: How to Use Your Head in Dual Pointing Tasks  

E-print Network

The utility of vision-based face tracking for dual pointing tasks is evaluated. We first describe a 3-D face tracking technique based on real-time parametric motion-stereo, which is non-invasive, robust, and self-initialized. ...

Darrell, Trevor

2002-01-01

129

Workflow Modelling and Analysis Based on the Construction of Task Models  

PubMed Central

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

Cravo, Glória

2015-01-01

130

Workflow modelling and analysis based on the construction of task models.  

PubMed

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

Cravo, Glória

2015-01-01

131

Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures  

PubMed Central

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

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

2009-01-01

132

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

SciTech Connect

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

Ikejimba, Lynda C., E-mail: lci@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Kiarashi, Nooshin [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)] [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Ghate, Sujata V. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States)] [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States) [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27705 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27705 (United States); Lo, Joseph Y. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States) [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27705 (United States)

2014-06-15

133

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

PubMed Central

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

Baus, Oliver; Bouchard, Stéphane

2014-01-01

134

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

Microsoft Academic Search

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

Anila Bello; Margaret M Quinn; Melissa J Perry; Donald K Milton

2009-01-01

135

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

SciTech Connect

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.

Hanson, K.M.

1991-01-01

136

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

NASA Astrophysics Data System (ADS)

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.

Pippin, Charles E.; Christensen, Henrik

2011-06-01

137

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

PubMed Central

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

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

138

Forecasting exposure to volcanic ash based on ash dispersion modeling  

NASA Astrophysics Data System (ADS)

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

Peterson, Rorik A.; Dean, Ken G.

2008-03-01

139

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

140

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

PubMed

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

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

2014-01-01

141

Population-Based Assessment of Exposure to Risk Behaviors in Motion Pictures  

Microsoft Academic Search

The aim of most population-based studies of media is to relate a specific exposure to an outcome of interest. A research program has been developed that evaluates exposure to different components of movies in an attempt of assess the association of such exposure with the adoption of substance use during adolescence. To assess exposure to movie substance use, one must

James D. Sargent; Keilah A. Worth; Michael Beach; Meg Gerrard; Todd F. Heatherton

2008-01-01

142

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

NASA Technical Reports Server (NTRS)

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

Edmiston, R. D.

1972-01-01

143

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

PubMed Central

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

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

2005-01-01

144

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

145

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

PubMed

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

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

2015-01-21

146

Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures  

SciTech Connect

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.

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

2009-01-01

147

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

PubMed

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

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

2013-06-01

148

Automated Classification of fMRI Data Employing Trial-based Imagery Tasks  

PubMed Central

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

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

2009-01-01

149

Moving From External Exposure Concentration to Internal Dose: Duration Extrapolation Based on Physiologically Based Pharmacokinetic Derived Estimates of Internal Dose  

Microsoft Academic Search

The potential human health risk(s) from chemical exposure must frequently be assessed under conditions for which adequate human or animal data are not available. The default method for exposure-duration adjustment, based on Haber's rule, C (external exposure concentration) or C (the ten Berge modification) × t (exposure duration) = K (a constant toxic effect), has been criticized for prediction errors.

Jane Ellen Simmons; Marina V. Evans; William K. Boyes

2005-01-01

150

Modeling and Simulation of a Dynamic Task-Based Runtime System for Heterogeneous  

E-print Network

Modeling and Simulation of a Dynamic Task-Based Runtime System for Heterogeneous MultiPU, a dynamic runtime for hybrid architectures, over SimGrid, a versatile simulator for distributed systems to quickly decide which optimization to enable or whether it is worth investing in higher-end GPUs or not. 1

Boyer, Edmond

151

Model-Based Ambient Analysis of Human Task Execution Fiemke Both, Mark Hoogendoorn, Jan Treur  

E-print Network

Model-Based Ambient Analysis of Human Task Execution Fiemke Both, Mark Hoogendoorn, Jan Treur Vrije://www.cs.vu.nl/~{ fboth, mhoogen, treur} ABSTRACT One of the challenges for ambient intelligent agents to support a human. In this paper an ambient agent model is presented that is able to obtain such an awareness of the human

Treur, Jan

152

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

ERIC Educational Resources Information Center

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

Libbon, Stephanie

2004-01-01

153

A Comparison Study: Sketch-Based Interfaces versus WIMP Interfaces in Three Dimensional Modeling Tasks  

Microsoft Academic Search

Sketch-Based Interfaces are becoming a popular interaction style for many applications. The interaction style tries to recreate the experience of sketching that is similar to real paper and pencil drawings.They are being used to accomplish tasks related to geometric modeling, animation, architecture, design, music, and learning, among others. In this work we evaluate and compare two interaction approaches, Sketch and

Tiago Lemos De Araujo Machado; Alex Sandro Gomes; Marcelo Walter

2009-01-01

154

Performance-Based Learning: Aligning Experiential Tasks and Assessment to Increase Learning. Second Edition  

ERIC Educational Resources Information Center

Teachers can promote long-lasting learning, build higher-order thinking skills, develop individual student accountability, and increase student achievement by incorporating performance learning tasks into the curriculum. In this second edition of "Performance-Based Learning," Sally Berman demonstrates how this model can be modified for learners at…

Berman, Sally

2007-01-01

155

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

ERIC Educational Resources Information Center

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

Jee, Min Jung

2010-01-01

156

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

ERIC Educational Resources Information Center

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…

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

157

The Development and Implementation of Task-Based Writing Performance Assessment for Japanese Learners of English  

ERIC Educational Resources Information Center

The main purpose of this research is 1) to establish a framework for the test development and the constructs of writing performance test, 2) to implement a developed writing performance assessment, and 3) to examine the degree of reliability and validity of the assessment tasks and rating scales. Construct-based processing approach to testing…

Sugita, Yoshihito

2009-01-01

158

A Web-Based Task-Tracking Collaboration System for the Florida Public Hurricane Loss Model  

E-print Network

such as hurricanes may cause tremendous economic and human losses. In 2005, for instance, Hurricane Katrina causedA Web-Based Task-Tracking Collaboration System for the Florida Public Hurricane Loss Model Raul, FL 33199, U.S.A. hamids@fiu.edu Abstract--The Florida Public Hurricane Loss Model (FPHLM) is a large

Chen, Shu-Ching

159

Exploring Adaptive Dialogue Based on a Robot's Awareness of Human Gaze and Task Progress  

E-print Network

, Experimentation, Human Factors, Theory. Keywords Human-robot interaction, human-robot dialogue, adaptive dialogueExploring Adaptive Dialogue Based on a Robot's Awareness of Human Gaze and Task Progress Cristen When a robot provides direction--as a guide, an assistant, or as an instructor--the robot may have

Fussell, Susan R.

160

Experimental Analysis of Task-based Energy Consumption in Cloud Computing Systems  

E-print Network

Experimental Analysis of Task-based Energy Consumption in Cloud Computing Systems Feifei Chen, John is that large cloud data centres consume large amounts of energy and produce significant carbon footprints that minimise energy consumption while guaranteeing Service Level Agreements (SLAs). In order to achieve

Schneider, Jean-Guy

161

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

ERIC Educational Resources Information Center

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…

Hu, Ran

2013-01-01

162

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

ERIC Educational Resources Information Center

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

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

163

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

ERIC Educational Resources Information Center

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

Dunne, B. Greg

2014-01-01

164

Cosmic radiation exposure on Canadian-based commercial airline routes.  

PubMed

As a result of the recent recommendations of ICRP 60 and in anticipation of possible regulation on occupational exposure of commercial aircrew, a two-part investigation was carried out over a one-year period to determine the total dose equivalent on representative Canadian-based flight routes. As part of the study, a dedicated scientific measurement flight (using both a conventional suite of powered detectors and passive dosimetry) was used to characterise the complex mixed radiation field and to intercompare the various instrumentation. In the other part of the study, volunteer aircrew carried (passive) neutron bubble detectors during their routine flight duties. From these measurements, the total dose equivalent was derived for a given route with a knowledge of the neutron fraction as determined from the scientific flight and computer code (CARI-LF) calculations. This investigation has yielded an extensive database of over 3100 measurements providing the total dose equivalent for 385 different routes. By folding in flight frequency information and the accumulated flight hours, the annual occupational exposures of 26 flight crew have also been determined. This study has indicated that most Canadian-based domestic and international aircrew will exceed the proposed annual ICRP 60 public limit of 1 mSv.y-1, but will he well below the occupational limit of 20 mSv.y-1. PMID:11542925

Lewis, B J; Tume, P; Bennett, L G; Pierre, M; Green, A R; Cousins, T; Hoffarth, B E; Jones, T A; Brisson, J R

1999-01-01

165

Behavior-Based Multi-Robot Collaboration for Autonomous Construction Tasks  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

166

Performance Monitoring and Analysis of Task-Based OpenMP  

PubMed Central

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

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

2013-01-01

167

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

PubMed

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

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

2014-08-28

168

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

PubMed Central

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

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

2014-01-01

169

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

SciTech Connect

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

Orr, J.L.; Rogers, W.R.; Smith, H.D. [Southwest Research Inst., San Antonio, TX (United States). Dept. of Biosciences and Bioengineering

1995-12-31

170

Short-term exposure to mobile phone base station signals does not affect cognitive functioning or physiological measures in individuals who report sensitivity to electromagnetic fields and controls.  

PubMed

Individuals who report sensitivity to electromagnetic fields often report cognitive impairments that they believe are due to exposure to mobile phone technology. Previous research in this area has revealed mixed results, however, with the majority of research only testing control individuals. Two studies using control and self-reported sensitive participants found inconsistent effects of mobile phone base stations on cognitive functioning. The aim of the present study was to clarify whether short-term (50 min) exposure at 10 mW/m(2) to typical Global System for Mobile Communication (GSM) and Universal Mobile Telecommunications System (UMTS) base station signals affects attention, memory, and physiological endpoints in sensitive and control participants. Data from 44 sensitive and 44 matched-control participants who performed the digit symbol substitution task (DSST), digit span task (DS), and a mental arithmetic task (MA), while being exposed to GSM, UMTS, and sham signals under double-blind conditions were analyzed. Overall, cognitive functioning was not affected by short-term exposure to either GSM or UMTS signals in the current study. Nor did exposure affect the physiological measurements of blood volume pulse (BVP), heart rate (HR), and skin conductance (SC) that were taken while participants performed the cognitive tasks. PMID:19475647

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Fox, Elaine

2009-10-01

171

Statistical-Based Response-Time Analysis of Systems with Execution Dependencies between Tasks  

Microsoft Academic Search

This paper presents a novel statistical-based approach to Worst-Case Response-Time (WCRT) analysis of complex real-time system models. These system models have been tailored to capture intricate execution dependencies between tasks, inspired by real industrial control systems. The proposed WCRT estimation algorithm is based on Extreme Value Theory (EVT) and produces both WCRT estimates together with a probability of being exceeded.

Yue Lu; Thomas Nolte; Johan Kraft; Christer Norström

2010-01-01

172

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

PubMed

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

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

2013-08-01

173

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

PubMed

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

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

2003-01-01

174

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

ERIC Educational Resources Information Center

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

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

2006-01-01

175

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

176

Population-Based Assessment of Exposure to Risk Behaviors in Motion Pictures.  

PubMed

The aim of most population-based studies of media is to relate a specific exposure to an outcome of interest. A research program has been developed that evaluates exposure to different components of movies in an attempt of assess the association of such exposure with the adoption of substance use during adolescence. To assess exposure to movie substance use, one must measure both viewing time and content. In developing the exposure measure, the study team was interested in circumventing a common problem in exposure measurement, where measures often conflate exposure to media with attention to media. Our aim in this paper is to present a validated measure of exposure to entertainment media, the Beach method, which combines recognition of a movie title with content analysis of the movie for substance use, to generate population based measures of exposure to substance use in this form of entertainment. PMID:19122801

Sargent, James D; Worth, Keilah A; Beach, Michael; Gerrard, Meg; Heatherton, Todd F

2008-01-01

177

Population-Based Assessment of Exposure to Risk Behaviors in Motion Pictures  

PubMed Central

The aim of most population-based studies of media is to relate a specific exposure to an outcome of interest. A research program has been developed that evaluates exposure to different components of movies in an attempt of assess the association of such exposure with the adoption of substance use during adolescence. To assess exposure to movie substance use, one must measure both viewing time and content. In developing the exposure measure, the study team was interested in circumventing a common problem in exposure measurement, where measures often conflate exposure to media with attention to media. Our aim in this paper is to present a validated measure of exposure to entertainment media, the Beach method, which combines recognition of a movie title with content analysis of the movie for substance use, to generate population based measures of exposure to substance use in this form of entertainment. PMID:19122801

Sargent, James D.; Worth, Keilah A.; Beach, Michael; Gerrard, Meg; Heatherton, Todd F.

2008-01-01

178

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

PubMed

We consider the problem of classification of imaginary motor tasks from electroencephalography (EEG) data for brain-computer interfaces (BCIs) and propose a new approach based on hidden conditional random fields (HCRFs). HCRFs are discriminative graphical models that are attractive for this problem because they (1) exploit the temporal structure of EEG; (2) include latent variables that can be used to model different brain states in the signal; and (3) involve learned statistical models matched to the classification task, avoiding some of the limitations of generative models. Our approach involves spatial filtering of the EEG signals and estimation of power spectra based on autoregressive modeling of temporal segments of the EEG signals. Given this time-frequency representation, we select certain frequency bands that are known to be associated with execution of motor tasks. These selected features constitute the data that are fed to the HCRF, parameters of which are learned from training data. Inference algorithms on the HCRFs are used for the classification of motor tasks. We experimentally compare this approach to the best performing methods in BCI competition IV as well as a number of more recent methods and observe that our proposed method yields better classification accuracy. PMID:22414728

Saa, Jaime F Delgado; Çetin, Müjdat

2012-04-01

179

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

NASA Astrophysics Data System (ADS)

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

Delgado Saa, Jaime F.; Çetin, Müjdat

2012-04-01

180

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

ERIC Educational Resources Information Center

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

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

2007-01-01

181

Neonatal choline supplementation ameliorates the effects of prenatal alcohol exposure on a discrimination learning task in rats  

Microsoft Academic Search

Prenatal alcohol exposure can disrupt brain development and lead to a myriad of behavioral alterations, including motor coordination deficits, hyperactivity, and learning deficits. There remains a need, however, to identify treatments and interventions for reducing the severity of alcohol-related neurodevelopmental disorders. Some of the alcohol-induced deficits in learning may be related to alterations in cholinergic functioning. Interestingly, there is a

Jennifer D Thomas; Michael H La Fiette; Vincent R. E Quinn; Edward P Riley

2000-01-01

182

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

Microsoft Academic Search

Cigarette smoking is associated with a wide variety of adverse reproductive outcomes, including increased infant mortality and decreased birth weight. Prenatal exposure to tobacco smoke, of which nicotine is a major teratogenic component, has also been linked to the acceleration of the risk for different psychiatric disorders, including conduct disorder and attention deficit hyperactivity disorder (ADHD). Whether this increased risk

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

2011-01-01

183

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

ERIC Educational Resources Information Center

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

Gan, Zhengdong

2012-01-01

184

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

ERIC Educational Resources Information Center

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

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

2007-01-01

185

Patient-based radiographic exposure factor selection: a systematic review  

PubMed Central

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.

Ching, William; Robinson, John; McEntee, Mark

2014-01-01

186

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.

187

Capturing Dynamic Patterns of Task-Based Functional Connectivity with EEG  

PubMed Central

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

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

2012-01-01

188

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

PubMed

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

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

2013-02-01

189

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

PubMed

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

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

2014-01-01

190

An approach to situational market segmentation on on-line newspapers based on current tasks  

Microsoft Academic Search

We discuss how a task-based situational market segmentation may be applied to on-line newspapers, distinguishing between fact finding, information gathering and browsing. During a period of four weeks we had 41 users keep a diary and recorded their surfing behavior on different on-line newspapers. The results of a Naive Bayes classification with feature selection indicate that content-related attributes such as

Anne Gutschmidt

2010-01-01

191

Addressing the intercultural via task-based language teaching: possibility or problem?  

Microsoft Academic Search

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 dimension. Using findings that emerge from a series of one-to-one interviews, this article

Martin East

2012-01-01

192

A Margin-of-Exposure Approach to Assessment of Noncancer Risks of Dioxins Based on Human Exposure and Response Data  

PubMed Central

Background Risk assessment of human environmental exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and other dioxin-like compounds is complicated by several factors, including limitations in measuring intakes because of the low concentrations of these compounds in foods and the environment and interspecies differences in pharmacokinetics and responses. Objectives We examined the feasibility of relying directly on human studies of exposure and potential responses to PCDD/PCDFs and related compounds in terms of measured lipid-adjusted concentrations to assess margin of exposure (MOE) in a quantitative, benchmark dose (BMD)–based framework using representative exposure and selected response data sets. Methods We characterize estimated central tendency and upper-bound general U.S. population lipid-adjusted concentrations of PCDD/PCDFs from the 1970s and early 2000s based on available data sets. Estimates of benchmark concentrations for three example responses of interest (induction of cytochrome P4501A2 activity, dental anomalies, and neonatal thyroid hormone alterations) were derived based on selected human studies. Results The exposure data sets indicate that current serum lipid concentrations in young adults are approximately 6- to 7-fold lower than 1970s-era concentrations. Estimated MOEs for each end point based on current serum lipid concentrations range from < 10 for neonatal thyroid hormone concentrations to > 100 for dental anomalies—approximately 6-fold greater than would have existed during the 1970s. Conclusions Human studies of dioxin exposure and outcomes can be used in a BMD framework for quantitative assessments of MOE. Incomplete exposure characterization can complicate the use of such studies in a BMD framework. PMID:18941576

Aylward, Lesa L.; Goodman, Julie E.; Charnley, Gail; Rhomberg, Lorenz R.

2008-01-01

193

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

PubMed

Objective. The number of items of a P300-based brain-computer interface (BCI) should be adjustable in accordance with the requirements of the specific tasks. To address this issue, we propose a novel task-oriented optimal approach aimed at increasing the performance of general P300 BCIs with different numbers of items. Approach. First, we proposed a stimulus presentation with variable dimensions (VD) paradigm as a generalization of the conventional single-character (SC) and row-column (RC) stimulus paradigms. Furthermore, an embedding design approach was employed for any given number of items. Finally, based on the score-P model of each subject, the VD flash pattern was selected by a linear interpolation approach for a certain task. Main results. The results indicate that the optimal BCI design consistently outperforms the conventional approaches, i.e., the SC and RC paradigms. Specifically, there is significant improvement in the practical information transfer rate for a large number of items. Significance. The results suggest that the proposed optimal approach would provide useful guidance in the practical design of general P300-based BCIs. PMID:25080373

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

2014-10-01

194

Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site  

SciTech Connect

As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

Thompson, C.B.; McArthur, R.D. [Univ. and Community College System of Nevada, Las Vegas, NV (United States); Hutchinson, S.W. [Mead Johnson Nutritional Group, Evansville, IN (United States)

1994-09-01

195

Development of vision-based autonomous robotic fish and its application in water-polo-attacking task  

Microsoft Academic Search

This paper presents the design and locomotion control of a vision-based autonomous robotic fish, and its application in water-polo-attacking task. Most of previous work on task strategies of autonomous robots is focused on the terrestrial robots and seldom deals with underwater applications. In fact, the tasks in underwater environment are more challenging than those in ground circumstances due to the

Wei Zhao; Yonghui Hu; Guangming Xie; Yingmin Jia

2008-01-01

196

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

NASA Astrophysics Data System (ADS)

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

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-12-01

197

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

PubMed

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

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

2013-09-01

198

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...

199

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

PubMed

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

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

2009-01-01

200

An Approach to Modeling the Airplane Cooperative Design Process Based on Task-Related Work Breakdown Structure  

Microsoft Academic Search

To shorten the design period of airplane, improve the design quality and reduce the manufacture cost, the computer supported cooperative design has become one of the effective methods. In order to organize the airplane design coordination tasks reasonably and improve the group collaborative efficiency in CSCD, an airplane cooperative design model based on task-related work breakdown structure was presented. The

Kai Wang; Yi Liu; Wenzheng Li

2009-01-01

201

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

ERIC Educational Resources Information Center

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

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

2012-01-01

202

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

SciTech Connect

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.

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

203

Comparison of Modeling Approaches to Prioritize Chemicals Based on Estimates of Exposure and Exposure Potential  

EPA Science Inventory

While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecologic...

204

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

SciTech Connect

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.

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

205

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

PubMed Central

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

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

2011-01-01

206

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

ERIC Educational Resources Information Center

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

Gardner, Joel; Jeon, Tae

2010-01-01

207

A Heuristic Real-Time Parallel Scheduler Based on Task Structures  

E-print Network

] [6]. Many of these methods use the cost of computation and communications as the schedule objective the quality of a schedule. Among them, there are two that are most relevant here: Facilitates Task A facilitates Task B, if execution of Task A will decrease the du- ration of executing Task B, or increase its

Massachusetts at Amherst, University of

208

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

209

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

PubMed

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

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

2014-12-01

210

Evidence-based practices for thromboembolism prevention: summary of the ASPS Venous Thromboembolism Task Force Report.  

PubMed

In July of 2011, the American Society of Plastic Surgeons Executive Committee approved the Venous Thromboembolism Task Force Report. The report includes a summary of the scientific literature relevant to venous thromboembolism and plastic surgery along with five evidence-based recommendations. The recommendations are divided into two sections: risk stratification and prevention. The risk stratification recommendations are based on the 2005 Caprini Risk Assessment Module, which has been validated in the scientific literature as an effective tool for risk-stratifying plastic and reconstructive surgery patients based on individual risk factors for 60-day venous thromboembolism. The three prophylaxis recommendations are dependent on an individual patient's 2005 Caprini Risk Assessment Module score. PMID:22743901

Murphy, Robert X; Alderman, Amy; Gutowski, Karol; Kerrigan, Carolyn; Rosolowski, Karie; Schechter, Loren; Schmitz, Delaine; Wilkins, Edwin

2012-07-01

211

Derivation of safe health-based exposure limits for potential consumer exposure to styrene migrating into food from food containers.  

PubMed

Residual styrene present in polystyrene food packaging may migrate into food at low levels. To assure safe use, safe exposure levels are derived for consumers potentially exposed via food using No/Low Adverse Effect Levels from animal and human studies and assessment factors proposed by European organisations (EFSA, ECHA, ECETOC). Ototoxicity and developmental toxicity in rats and human ototoxicity and effects on colour discrimination have been identified as the most relevant toxicological properties for styrene health assessments. Safe exposure levels derived from animal studies with assessment factors of EFSA and ECHA were expectedly much lower than those using the ECETOC approach. Comparable safe exposure levels were obtained from human data with all sets of assessment factors while ototoxicity in rats led to major differences. The safe exposure levels finally selected based on criteria of science and health protection converged to the range of 90-120 mg/person/d. Assuming a consumption of 1 kg food/d for an adult, this translates to 90 mg styrene migration into 1 kg food as safe for consumers. This assessment supports a health based Specific Migration Limit of 90 ppm, a value somewhat higher than the current overall migration limit of 60 ppm in the European Union. PMID:24316211

Gelbke, Heinz-Peter; Banton, Marcy; Faes, Eric; Leibold, Edgar; Pemberton, Mark; Duhayon, Sophie

2014-02-01

212

The software V&V tasks for a safety-critical software based protection system in nuclear power plants  

Microsoft Academic Search

This paper introduces the software life-cycle based V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop the programmable logic controller (PLQ for safety-critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of the safety-critical software based digital

S. W. Cheon; G. Y. Park; K. H. Cha; J. S. Lee; K. C. Kwon

2005-01-01

213

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. ...

214

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

215

Application of ensemble classifier in EEG-based motor imagery tasks  

NASA Astrophysics Data System (ADS)

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.

Liu, Bianhong; Hao, Hongwei

2007-12-01

216

Task-specific noise exposure during manual concrete surface grinding in enclosed areas-influence of operation variables and dust control methods.  

PubMed

Noise exposure is a distinct hazard during hand-held concrete grinding activities, and its assessment is challenging because of the many variables involved. Noise dosimeters were used to examine the extent of personal noise exposure while concrete grinding was performed with a variety of grinder sizes, types, accessories, and available dust control methods. Noise monitoring was conducted in an enclosed area covering 52 task-specific grinding sessions lasting from 6 to 72 minutes. Noise levels, either in minute average noise level (Lavg, dBA) or in minute peak (dBC), during concrete grinding were significantly (P < 0.01) correlated with general ventilation (GV: on, off), dust control methods (uncontrolled, wet, Shop-Vac, HEPA, HEPA-Cyclone), grinding cup wheel (blade) sizes of 4-inch (100 mm), 5-inch (125 mm) and 6-inch (150 mm), and surface orientation (horizontal, inclined). Overall, minute Lavg during grinding was 97.0 ± 3.3 (mean ± SD), ranging from 87.9 to 113. The levels of minute Lavg during uncontrolled grinding (98.9 ± 5.2) or wet-grinding (98.5 ± 2.7) were significantly higher than those during local exhaust ventilation (LEV) grinding (96.2 ± 2.8). A 6-inch grinding cup wheel generated significantly higher noise levels (98.7 ± 2.8) than 5-inch (96.3 ± 3.2) or 4-inch (95.3 ± 3.5) cup wheels. The minute peak noise levels (dBC) during grinding was 113 ± 5.2 ranging from 104 to 153. The minute peak noise levels during uncontrolled grinding (119 ± 10.2) were significantly higher than those during wet-grinding (115 ± 4.5) and LEV-grinding (112 ± 3.4). A 6-inch grinding cup wheel generated significantly higher minute peak noise levels (115 ± 5.3) than 5-inch (112 ± 4.5) or 4-inch (111 ± 5.4) cup wheels. Assuming an 8-hour work shift, the results indicated that noise exposure levels during concrete grinding in enclosed areas exceeded the recommended permissible exposure limits and workers should be protected by engineering control methods, safe work practices, and/or personal protective devices. PMID:23926952

Akbar-Khanzadeh, Farhang; Ames, April L; Milz, Sheryl A; Akbar-Khanzadeh, Mahboubeh

2013-01-01

217

Imaging Tasks Scheduling for High-Altitude Airship in Emergency Condition Based on Energy-Aware Strategy  

PubMed Central

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

Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

2013-01-01

218

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

PubMed

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

Izakian, Hesam; Abraham, Ajith; Snášel, Václav

2009-01-01

219

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...

220

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...

221

Physiologically-based pharmacokinetic (PBPK) models in human exposure assessment  

SciTech Connect

The potential dose received by an individual during defined exposure situations can be determined using personal dosimeters or estimated by combining information on exposure scenarios with the environmental concentration (C.) of chemicals. With the latter approach, not only the potential dose but also the internal dose (i.e., amount of chemical that has been absorbed and available for interaction with receptors) and biologically-effective dose (i.e., amount of chemical that actually reaches the cellular sites where interaction with macromolecules occur) can be estimated if C. is provided as an input to PBPK models. These models are mathematical representations of the interrelationships among the critical determinants of the absorption, distribution, metabolism and excretion of chemicals in biota. Since the compartments in this model correspond to biologically relevant tissues or tissue groups, the amount of chemical reaching specific target organ(s) can be estimated. Further, the PBPK models permit the use of biological monitoring data such as urinary levels of metabolites, hemoglobin adduct levels, and alveolar air concentrations, to reconstruct the exposure levels and scenarios for specific subgroups of populations. These models are also useful in providing estimates of target tissue dose in humans simultaneously exposed to chemicals in various media (air, water, soil, food) by different routes (oral, dermal, inhalation). Several examples of exposure assessment for volatile organic chemicals using PBPK models for mammals will be presented, and the strategies for development of these models for other classes of chemicals highlighted.

Krishnan, K. [Univ. de Montreal, Quebec (Canada)

1995-12-31

222

Worldwide flight and ground-based exposure of composite materials  

NASA Technical Reports Server (NTRS)

The long-term durability of those advanced composite materials which are applicable to aircraft structures was discussed. The composite components of various military and commercial aircraft and helicopters were reviewed. Both ground exposure and flight service were assessed in terms of their impact upon composite structure durability. The ACEE Program is mentioned briefly.

Dexter, H. B.; Baker, D. J.

1984-01-01

223

Identity-Based Chameleon Hash Scheme Without Key Exposure  

E-print Network

information, he then can use #12;2 it to deny other signatures given to the recipient. In the worst case hashing [28] both suffer from the key exposure problem. Ateniese and de Medeiros [1] first introduced message in other transactions. However, this kind of transaction-specific chameleon hash scheme still

224

Exposure-Based Screening for Nipah Virus Encephalitis, Bangladesh  

PubMed Central

We measured the performance of exposure screening questions to identify Nipah virus encephalitis in hospitalized encephalitis patients during the 2012–13 Nipah virus season in Bangladesh. The sensitivity (93%), specificity (82%), positive predictive value (37%), and negative predictive value (99%) results suggested that screening questions could more quickly identify persons with Nipah virus encephalitis. PMID:25625615

Luby, Stephen P.; Ströher, Ute; Daszak, Peter; Sultana, Sharmin; Afroj, Sayma; Rahman, Mahmudur; Gurley, Emily S.

2015-01-01

225

Biology Based Lung Cancer Model for Chronic Low Radon Exposures  

SciTech Connect

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.

Truta-Popa, Lucia-Adina [Faculty of Environmental Sciences, Babes-Bolyai University, 400192 Cluj-Napoca (Romania); Division of Physics and Biophysics, Department of Materials Engineering and Physics, University of Salzburg, 5020 Salzburg (Austria); Hofmann, Werner; Fakir, Hatim [Division of Physics and Biophysics, Department of Materials Engineering and Physics, University of Salzburg, 5020 Salzburg (Austria); Cosma, Constantin [Faculty of Environmental Sciences, Babes-Bolyai University, 400192 Cluj-Napoca (Romania)

2008-08-07

226

Supernumerary Robotic Limbs : task planning, execution, and prediction-based coordination with the human wearer  

E-print Network

Full automation of repetitive and/or specialized tasks has become a preferred means to meet the needs of manufacturing industries. However, some tasks cannot be fully automated due to their complexity or the nature of the ...

Llorens-Bonilla, Baldin Adolfo

2013-01-01

227

Paleoglaciation of the Tibetan Plateau based on exposure ages and ELA depression estimates  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau holds a major part of all glaciers outside the polar regions and an ample record of past glaciations. The glacial history of the Tibetan Plateau has attracted significant interest, with a large body of research investigating the extent, timing, and climatic implications of past glaciations. Here I present an extensive compilation of exposure ages and equilibrium line altitude (ELA) depression estimates from glacial deposits across the Tibetan Plateau to address the timing and degree of past glaciations. I compiled Be-10 exposure age data for a total of 1877 samples and recalculated exposure ages using an updated (lower) global Be-10 production rate. All samples were organized in groups of individual glacial deposits where each deposit represents one glacial event enabling evaluation of the exposure age clustering. For each glacial deposit I estimated the ELA depression based on a simple toe to headwall ratio approach using Google Earth. To discriminate good (well-clustered) from poor (scattered) exposure age groups the glacial deposits were divided into three groups based on exposure age clustering. A major part of the glacial deposits have scattered exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered exposure age groups are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak in age between 10 and 30 ka, indicating glacial advances during the global last glacial maximum (LGM). A large number of exposure ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but a major part is remarkably low. Average ELA depressions of 333 ± 191 m for the LGM and 494 ± 280 m for the pre-LGM exposure indicate restricted glacier expansion and limited glacial cooling.

Heyman, Jakob

2014-05-01

228

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

229

Vision-Based Long-Range 3D Tracking, applied to Underground Surveying Tasks  

NASA Astrophysics Data System (ADS)

To address the need of highly automated positioning systems in underground construction, we present a long-range 3D tracking system based on infrared optical markers. It provides continuous 3D position estimation of static or kinematic targets with low latency over a tracking volume of 12 m x 8 m x 70 m (width x height x depth). Over the entire volume, relative 3D point accuracy with a maximal deviation ? 22 mm is ensured with possible target rotations of yaw, pitch = 0 - 45° and roll = 0 - 360°. No preliminary sighting of target(s) is necessary since the system automatically locks onto a target without user intervention and autonomously starts tracking as soon as a target is within the view of the system. The proposed system needs a minimal hardware setup, consisting of two machine vision cameras and a standard workstation for data processing. This allows for quick installation with minimal disturbance of construction work. The data processing pipeline ensures camera calibration and tracking during on-going underground activities. Tests in real underground scenarios prove the system's capabilities to act as 3D position measurement platform for multiple underground tasks that require long range, low latency and high accuracy. Those tasks include simultaneously tracking of personnel, machines or robots.

Mossel, Annette; Gerstweiler, Georg; Vonach, Emanuel; Kaufmann, Hannes; Chmelina, Klaus

2014-04-01

230

Complexity, Accuracy, Fluency and Lexis in Task-Based Performance: A Synthesis of the Ealing Research  

ERIC Educational Resources Information Center

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…

Skehan, Peter; Foster, Pauline

2012-01-01

231

Testing and optimizing the performance of a floor-based task conditioning system  

Microsoft Academic Search

During recent years an increasing amount of attention has been paid to air distribution systems that individually condition the immediate environments of office workers within their workstations. As with task lighting systems, the controls for these ‘task conditioning’ systems are partially or entirely decentralized and under the control of the occupants. Among the primary types of task conditioning systems (floor-,

F. S. Bauman; E. A. Arens; S. Tanabe; H. Zhang; A. Baharlo

1995-01-01

232

Method for carrier aircraft task flow safety analysis based on TPN  

Microsoft Academic Search

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

Zhaoguang Peng; Tingdi Zhao; Jin Tian

2011-01-01

233

A Comparison of Exposure Control Procedures in CAT Systems Based on Different Measurement Models for Testlets  

ERIC Educational Resources Information Center

This study compared several exposure control procedures for CAT systems based on the three-parameter logistic testlet response theory model (Wang, Bradlow, & Wainer, 2002) and Masters' (1982) partial credit model when applied to a pool consisting entirely of testlets. The exposure control procedures studied were the modified within 0.10 logits…

Boyd, Aimee M.; Dodd, Barbara; Fitzpatrick, Steven

2013-01-01

234

EPA-Expo-Box: A web-based Toolbox for Exposure Assessors  

EPA Science Inventory

EPA EXPOsure toolBOX, or EPA-Expo-Box, is a web-based toolbox that has been developed by EPA’s Office of Research and Development (ORD), National Center for Environmental Assessment (NCEA). It is intended for exposure and risk assessors and it comprises a series of Tool Set...

235

Discrete logarithm based chameleon hashing and signatures without key exposure q  

E-print Network

Discrete logarithm based chameleon hashing and signatures without key exposure q Xiaofeng Chen a in revised form 18 March 2011 Accepted 28 March 2011 Available online 6 May 2011 a b s t r a c t Chameleon message. However, the initial constructions of chameleon sig- natures suffer from the key exposure problem

Kim, Kwangjo

236

Biomonitoring of exposure to lewisite based on adducts to haemoglobin.  

PubMed

The development of a procedure for retrospective detection and quantitation of exposure to the arsenical dichloro(2-chlorovinyl)arsine (lewisite; L1) has been initiated. Upon incubation of human blood with [14C]L1 (20 nM-0.2 mM) in vitro, more than 90% of the total radioactivity was found in the erythrocytes and 25-50% of the radioactivity becomes associated with globin. Evidence was obtained for the presence of several binding sites. One type of binding was identified as L1-induced crosslinking of cysteine residues 93 and 112 of the beta-globin chain. A method was developed for extraction of bound and unbound 2-chlorovinylarsonous acid (CVAA), a major metabolite of L1, from whole blood after treatment with 2,3-dimercapto-1-propanol (BAL). Subsequent to derivatization with heptafluorobutyryl imidazole, the CVAA-BAL derivative could be analysed at a 40-fmol level by means of gas chromatography-mass spectroscopy (GC-MS) under electron impact conditions. With this procedure, in vitro exposure of human blood to 1 nM L1 could be determined. The same procedure was applied to the analysis of human urine samples spiked with CVAA. In vivo exposure of guinea pigs could be established at least 240 h after subcutaneous administration of the agent (0.25 mg/kg) by the determination of bound and unbound CVAA in the blood. In the urine of these animals, CVAA could be detected for 12 h after exposure. PMID:10959794

Fidder, A; Noort, D; Hulst, A G; de Jong, L P; Benschop, H P

2000-07-01

237

Real-Time Motion Planning for a Volleyball Robot Task Based on a Multi-Agent Technique  

Microsoft Academic Search

This paper takes the volleyball robot task as an example of a dynamic manipulation task and presents a multi-agent-based motion-planning\\u000a framework for it. Each subtask in the motion planning is defined as an agent. The motion planning is accomplished by the solution\\u000a of each agent activated by a blackboard. It is convenient to extend the module and enable real-time control

Pei-yan Zhang; Lü Tian-sheng

2007-01-01

238

Paleoglaciation of the Tibetan Plateau and surrounding mountains based on exposure ages and ELA depression estimates  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30 ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337 ± 197 m for the LGM and 494 ± 280 m for the pre-LGM indicate restricted glacier expansion.

Heyman, Jakob

2014-05-01

239

Lunar base applications of superconductivity: Lunar base systems study task 3.4  

NASA Technical Reports Server (NTRS)

The application of superconductor technology to several key aspects of an advanced-stage Lunar Base is described. Applications in magnetic energy storage, electromagnetic launching, and radiation shielding are discussed.

1988-01-01

240

Subclass-based multi-task learning for Alzheimer's disease diagnosis  

PubMed Central

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

Suk, Heung-II; Lee, Seong-Whan; Shen, Dinggang

2014-01-01

241

GLMdenoise: a fast, automated technique for denoising task-based fMRI data  

PubMed Central

In task-based functional magnetic resonance imaging (fMRI), researchers seek to measure fMRI signals related to a given task or condition. In many circumstances, measuring this signal of interest is limited by noise. In this study, we present GLMdenoise, a technique that improves signal-to-noise ratio (SNR) by entering noise regressors into a general linear model (GLM) analysis of fMRI data. The noise regressors are derived by conducting an initial model fit to determine voxels unrelated to the experimental paradigm, performing principal components analysis (PCA) on the time-series of these voxels, and using cross-validation to select the optimal number of principal components to use as noise regressors. Due to the use of data resampling, GLMdenoise requires and is best suited for datasets involving multiple runs (where conditions repeat across runs). We show that GLMdenoise consistently improves cross-validation accuracy of GLM estimates on a variety of event-related experimental datasets and is accompanied by substantial gains in SNR. To promote practical application of methods, we provide MATLAB code implementing GLMdenoise. Furthermore, to help compare GLMdenoise to other denoising methods, we present the Denoise Benchmark (DNB), a public database and architecture for evaluating denoising methods. The DNB consists of the datasets described in this paper, a code framework that enables automatic evaluation of a denoising method, and implementations of several denoising methods, including GLMdenoise, the use of motion parameters as noise regressors, ICA-based denoising, and RETROICOR/RVHRCOR. Using the DNB, we find that GLMdenoise performs best out of all of the denoising methods we tested. PMID:24381539

Kay, Kendrick N.; Rokem, Ariel; Winawer, Jonathan; Dougherty, Robert F.; Wandell, Brian A.

2013-01-01

242

Task Performance in Astronomical Adaptive Optics  

PubMed Central

In objective or task-based assessment of image quality, figures of merit are defined by the performance of some specific observer on some task of scientific interest. This methodology is well established in medical imaging but is just beginning to be applied in astronomy. In this paper we survey the theory needed to understand the performance of ideal or ideal-linear (Hotelling) observers on detection tasks with adaptive-optical data. The theory is illustrated by discussing its application to detection of exoplanets from a sequence of short-exposure images. PMID:20890393

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

2010-01-01

243

Systematic Uncertainties of Glacial Chronologies Based on Surface Exposure Dating  

NASA Astrophysics Data System (ADS)

Surface exposure dating using terrestrial cosmogenic nuclides provides the opportunity to establish glacial chronologies in semi-arid high mountain regions, where the lack of organic material for radiocarbon dating has limited our knowledge about the timing and the causes of glacial advances so far. However, several scaling systems and calculation schemes exist. This can result in significant systematic uncertainties, particularly at high altitudes as e.g. in the Central Andes. We present and discuss previously published exposure ages from Bolivia and Argentina in order to illustrate the extent of the current uncertainties. It is neither possible to unambiguously determine whether the local Last Glacial Maximum (local LGM) in the tropics occurred in-phase with or predated the global LGM, nor can the subsequent Late Glacial stages be dated accurately enough to infer temperature or precipitation changes at millennial-scale timescales. We then also present new results from the Tres Lagunas in the Sierra de Santa Victoria, NW Argentina. There we can compare our glacial exposure age chronology with bracketing radiocarbon ages from lake sediments. The Tres Lagunas may thus serve as a high-altitude calibration site for 10Be dating. Paleoclimatically, we conclude that glacial deposits in NW-Argentina document glacial advances in-phase with the global LGM, but that the prominent moraines there date to the Late Glacial. This coincides with the well-documented intensification and/or southward shift of the tropical circulation and reflects the strong precipitation-sensitivity of glaciers in arid and semi-arid environments.

Ilgner, J.; Zech, R.; Baechtiger, C.; Kubik, P. W.; Veit, H.

2008-12-01

244

Report of the APSAC Task Force on evidence-based service planning guidelines for child welfare.  

PubMed

This article presents the American Professional Society on the Abuse of Children (APSAC) Task Force report on the evidence-based service planning (EBSP) approach to child welfare services (CWS) plans and recommendations for practice. The focus of the policy report is on formal psychosocial services. CWS plans prescribe services to promote core child welfare objectives and to benefit children and families. The goal of EBSP is to construct service plans based on the general principles of evidence-based practice and prefer services with empirical support for clinical problems or needs associated with the causes or consequences of child abuse and neglect (CAN). EBSP aims to facilitate an overarching service approach that is collaborative, respectful, and includes services that are most likely to lead to outcomes on both family identified and child welfare mission goals. EBSP emphasizes a focused, assessment-driven, and science-informed approach that both favors plans that are sufficient and avoids overburdening families with compulsory services that address problems which are not directly related to the child welfare CAN referral. PMID:25505157

Berliner, Lucy; Fitzgerald, Monica M; Dorsey, Shannon; Chaffin, Mark; Ondersma, Steven J; Wilson, Charles

2015-02-01

245

Comparison of Deck- and Trial-Based Approaches to Advantageous Decision Making on the Iowa Gambling Task  

ERIC Educational Resources Information Center

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…

Visagan, Ravindran; Xiang, Ally; Lamar, Melissa

2012-01-01

246

Object-based task-level control: A hierarchical control architecture for remote operation of space robots  

NASA Technical Reports Server (NTRS)

Expanding man's presence in space requires capable, dexterous robots capable of being controlled from the Earth. Traditional 'hand-in-glove' control paradigms require the human operator to directly control virtually every aspect of the robot's operation. While the human provides excellent judgment and perception, human interaction is limited by low bandwidth, delayed communications. These delays make 'hand-in-glove' operation from Earth impractical. In order to alleviate many of the problems inherent to remote operation, Stanford University's Aerospace Robotics Laboratory (ARL) has developed the Object-Based Task-Level Control architecture. Object-Based Task-Level Control (OBTLC) removes the burden of teleoperation from the human operator and enables execution of tasks not possible with current techniques. OBTLC is a hierarchical approach to control where the human operator is able to specify high-level, object-related tasks through an intuitive graphical user interface. Infrequent task-level command replace constant joystick operations, eliminating communications bandwidth and time delay problems. The details of robot control and task execution are handled entirely by the robot and computer control system. The ARL has implemented the OBTLC architecture on a set of Free-Flying Space Robots. The capability of the OBTLC architecture has been demonstrated by controlling the ARL Free-Flying Space Robots from NASA Ames Research Center.

Stevens, H. D.; Miles, E. S.; Rock, S. J.; Cannon, R. H.

1994-01-01

247

Exposure assessment of mobile phone base station radiation in an outdoor environment using sequential surrogate modeling.  

PubMed

Human exposure to background radiofrequency electromagnetic fields (RF-EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF-EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04?km(2) for Global System for Mobile Communications (GSM) technology at 900?MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling. PMID:23315952

Aerts, Sam; Deschrijver, Dirk; Joseph, Wout; Verloock, Leen; Goeminne, Francis; Martens, Luc; Dhaene, Tom

2013-05-01

248

Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies  

PubMed Central

We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions. PMID:23100133

Safavynia, Seyed A.

2013-01-01

249

Analogical and Case-Based Reasoning for Predicting Satellite Task Schedulability  

Microsoft Academic Search

\\u000a Satellites represent scarce resources that must be carefully scheduled to maximize their value to service consumers. Near-optimal\\u000a satellite task scheduling is so computationally difficult that it typically takes several hours to schedule one day’s activities\\u000a for a set of satellites and tasks. Thus, often a requestor will not know if a task will be scheduled until it is too late

Pete Tinker; Jason Fox; Collin Green; Karen Casey; Chris Furmanski

2005-01-01

250

Simulation-Based Discomfort Prediction of the Lower Limb Handicapped with Prosthesis in the Climbing Tasks  

Microsoft Academic Search

This paper generalizes a discomfort model for climbing tasks of the handicapped with prosthesis limb. The model is integrated,\\u000a by ICT technology, into the simulated task scenario to indicate to what extent the climbing task causes discomfort and to\\u000a analyze the direct cause of discomfort at the micro-motion level. Furthermore, it can predict the potential harm and accidents\\u000a in the

Yan Fu; Shiqi Li; Mingqiang Yin; Yueqing Bian

2009-01-01

251

A Complete Methodology for Generating Multi-Robot Task Solutions using ASyMTRe-D and Market-Based Task Allocation  

E-print Network

both strongly-cooperative and weakly-cooperative multi-robot task solutions in the same application for weakly-cooperative task solutions. At the low level, coalitions that generate strongly-cooperative multi-robot task allocation approach is used to enable individual robots and/or coalitions to compete for weakly-cooperative

Parker, Lynne E.

252

A computer-based interactive game to train persons with cognitive impairments to perform recycling tasks independently.  

PubMed

This study assessed the possibility of training three people with cognitive impairments using a computer-based interactive game. A game was designed to provide task prompts in recycling scenarios, identify incorrect task steps on the fly, and help users learn to make corrections. Based on a multiple baseline design, the data showed that the three participants considerably increased their target response, which improved their vocational job skills during the intervention phases and enabled them to maintain the acquired job skills after intervention. The practical and developmental implications of the results are discussed. PMID:25262012

Chang, Yao-Jen; Kang, Ya-Shu; Liu, Fang-Lin

2014-12-01

253

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

E-print Network

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

Burnett, Louis E.

254

Effects of Dual Task Training with Visual Restriction and an Unstable Base on the Balance and Attention of Stroke Patients  

PubMed Central

[Purpose] The purpose of this study was to examine the effects of the visual restriction and unstable base dual-task training (VUDT), the visual restriction dual-task training (VDT), and the unstable base dual-task training (UDT) on the balance and attention of chronic stroke patients. [Subjects and Methods] The subjects were 38 chronic stroke patients, who were divided into two groups of 13 patients each and one group of 12 patients. They were given dual-task training for 30 minutes per session, three times a week, for eight weeks. Their balance was measured using the center of pressure (COP) migration distances, functional reach test (FRT), and Berg balance scale (BBS), and attention was measured with the Trail Making Tests and the Stroop test. [Results] In comparisons within each group, all the three groups showed significant differences before and after the training (p<0.05), and in the comparisons among the three groups, the VUDT group showed more significant differences compared with the other two groups in all tests (p<0.05). [Conclusion] Dual-task training applied with visual restriction and an unstable base in which the subjects attempted to maintain their balance was effective in improving the balance and attention of stroke patients, and the VUDT was more effective than VDT or UDT. PMID:24409024

Kim, Donghoon; Ko, Jooyeon; Woo, Youngkeun

2014-01-01

255

Lunar surface construction and assembly equipment study: Lunar Base Systems Study (LBSS) task 5.3  

NASA Technical Reports Server (NTRS)

A set of construction and assembly tasks required on the lunar surface was developed, different concepts for equipment applicable to the tasks determined, and leading candidate systems identified for future conceptual design. Data on surface construction and assembly equipment systems are necessary to facilitate an integrated review of a complete lunar scenario.

1988-01-01

256

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

E-print Network

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

Buenaposada Biencinto, José Miguel

257

Task-level imitation learning using variance-based movement optimization  

Microsoft Academic Search

Recent advances in the field of humanoid robotics increase the complexity of the tasks that such robots can perform. This makes it increasingly difficult and inconvenient to program these tasks manually. Furthermore, humanoid robots, in contrast to industrial robots, should in the distant future behave within a social environment. Therefore, it must be possible to extend the robot's abilities in

Manuel Mühlig; Michael Gienger; Sven Hellbach; Jochen J. Steil; Christian Goerick

2009-01-01

258

Machine Learning Based Online Performance Prediction for Runtime Parallelization and Task Scheduling  

SciTech Connect

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.

Li, J; Ma, X; Singh, K; Schulz, M; de Supinski, B R; McKee, S A

2008-10-09

259

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

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.

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

1980-04-09

260

Application of statistical modeling to occupational exposure assessment  

SciTech Connect

This dissertation applies statistical modeling to two problems: (1) describing a single worker's exposure distribution and estimating its associated arithemetic mean; and (2) describing the distribution of inhalation exposure levels among a population of respirator wearers while accounting for variability in ambient exposure and respirator penetration values within and between wearers. A task-based statistical construct for a single worker's exposure levels for a single agent is developed; the model accounts for variability in short-term time weighted average (TWA) exposure values within a task, and for variability in arithmetic mean exposure levels between tasks. Five sample survey designs for estimating a worker's arithmetic mean exposure level are examined. Stratified random sampling designs, in which short-term TWAs are measured for time periods selected on a task basis, can provide a more precise estimate of the arithmetic mean exposure level than the traditional survey design for the same fixed cost. For describing inhalation exposure levels (C{sub i}) among a population of air-purifying respirator wearers, a synthesis of lognormal one-way analysis of variance models for ambient exposure levels (C.) and respirator penetration (P) values provides the most tractable construct. The model is applied to assessing the risk of toxicant overexposure for a respirator wearer population. Overexposure to a chronic toxicant is equated with an arithmetic mean exposure level above the permissible exposure limit (PEL) value, while overexposure to an acute toxicant is equated with a 95th percentile exposure level above the PEL value.

Nicas, M.

1991-01-01

261

Biomarker-based calibration of retrospective exposure predictions of perfluorooctanoic acid.  

PubMed

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

Shin, Hyeong-Moo; Steenland, Kyle; Ryan, P Barry; Vieira, Verónica M; Bartell, Scott M

2014-05-20

262

38 CFR 3.316 - Claims based on chronic effects of exposure to mustard gas and Lewisite.  

Code of Federal Regulations, 2010 CFR

...based on chronic effects of exposure to mustard gas and Lewisite. 3.316 Section...based on chronic effects of exposure to mustard gas and Lewisite. (a) Except...Full-body exposure to nitrogen or sulfur mustard during active military service...

2010-07-01

263

OccIDEAS: Retrospective Occupational Exposure Assessment in Community-Based Studies Made Easier  

PubMed Central

Assessing occupational exposure in retrospective community-based case-control studies is difficult as measured exposure data are very seldom available. The expert assessment method is considered the most accurate way to attribute exposure but it is a time consuming and expensive process and may be seen as subjective, nonreproducible, and nontransparent. In this paper, we describe these problems and outline our solutions as operationalized in a web-based software application (OccIDEAS). The novel aspects of OccIDEAS are combining all steps in the assessment into one software package; enmeshing the process of assessment into the development of questionnaires; selecting the exposure(s) of interest; specifying rules for exposure assignment; allowing manual or automatic assessments; ensuring that circumstances in which exposure is possible for an individual are highlighted for review; providing reports to ensure consistency of assessment. Development of this application has the potential to make high-quality occupational assessment more efficient and accessible for epidemiological studies. PMID:20041014

Fritschi, Lin; Friesen, Melissa C.; Glass, Deborah; Benke, Geza; Girschik, Jennifer; Sadkowsky, Troy

2009-01-01

264

Inferring multi-target QSAR models with taxonomy-based multi-task learning  

PubMed Central

Background A plethora of studies indicate that the development of multi-target drugs is beneficial for complex diseases like cancer. Accurate QSAR models for each of the desired targets assist the optimization of a lead candidate by the prediction of affinity profiles. Often, the targets of a multi-target drug are sufficiently similar such that, in principle, knowledge can be transferred between the QSAR models to improve the model accuracy. In this study, we present two different multi-task algorithms from the field of transfer learning that can exploit the similarity between several targets to transfer knowledge between the target specific QSAR models. Results We evaluated the two methods on simulated data and a data set of 112 human kinases assembled from the public database ChEMBL. The relatedness between the kinase targets was derived from the taxonomy of the humane kinome. The experiments show that multi-task learning increases the performance compared to training separate models on both types of data given a sufficient similarity between the tasks. On the kinase data, the best multi-task approach improved the mean squared error of the QSAR models of 58 kinase targets. Conclusions Multi-task learning is a valuable approach for inferring multi-target QSAR models for lead optimization. The application of multi-task learning is most beneficial if knowledge can be transferred from a similar task with a lot of in-domain knowledge to a task with little in-domain knowledge. Furthermore, the benefit increases with a decreasing overlap between the chemical space spanned by the tasks. PMID:23842210

2013-01-01

265

The Relationship between Event-Based Prospective Memory and Ongoing Task Performance in Chimpanzees (Pan troglodytes)  

PubMed Central

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

Evans, Theodore A.; Perdue, Bonnie; Beran, Michael J.

2014-01-01

266

Reflections on Speech Motor Control Based on Phonatory and DDK Tasks in Dysarthric Subjects with Lesions in Different Cerebellar Loci  

ERIC Educational Resources Information Center

There are very few acoustic studies reflecting on the localization of speech function within the different loci of the cerebellum. Task based performance profile of subjects with lesion in different cerebellar loci is not reported. Also, the findings on nonfocal cerebellar lesions cannot be generalized to lesions restricted to the cerebellum.…

Vandana, V. P.

2007-01-01

267

A Location-Based Prompting System to Transition Autonomously through Vocational Tasks for Individuals with Cognitive Impairments  

ERIC Educational Resources Information Center

This study assessed the possibility of training two individuals with cognitive impairments using location-based task prompting system in a supported employment program. This study was carried out according to an ABAB sequence in which A represented the baseline and B represented intervention phases. Data showed that the two participants…

Chang, Yao-Jen; Wang, Tsen-Yung; Chen, Yan-Ru

2011-01-01

268

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

269

Teacher- and Learner-Led Discourse in Task-Based Grammar Instruction: Providing Procedural Assistance for L2 Morphosyntactic Development  

ERIC Educational Resources Information Center

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…

Toth, Paul D.

2008-01-01

270

Integrating English for Specific Purposes Courseware into Task-Based Learning in a Context of Preparing for International Trade Fairs  

ERIC Educational Resources Information Center

This study reports on integrating courseware for participating in international trade fairs into English for specific purposes (ESP) instruction at a technical university in Taiwan. An Information and Communication Technology (ICT) approach combining courseware integration with Task Based Learning (TBL), was adopted. Evaluation of implementing…

Tsai, Shu-Chiao

2013-01-01

271

"Lo Cotidiano": The Effectiveness of Critical Task-Based Instruction in Teaching the Culture of Everyday Life  

ERIC Educational Resources Information Center

Teaching cultural competency in the language classroom can be a challenge. This study explores the effectiveness of task-based instruction (Lee, 2000) on the learning of culture by students in college-level Spanish language courses. Students were required to record oral presentations, write essays, and make comparisons between the culture and…

García-Villada, Eduardo

2014-01-01

272

Teachers' Perceptions of Task-Based Language Teaching in English Classrooms in Taiwanese Junior High Schools  

ERIC Educational Resources Information Center

After introducing new curriculum guidelines during education reform, the Taiwan Ministry of Education has taken the lead in integrating a communicative approach into the new English language curriculum. Task-based language teaching (TBLT) is viewed as a realisation of communicative language teaching and is one of the most popular English language…

Lin, Tzu-Bin; Wu, Chiao-Wen

2012-01-01

273

Reading Guided by Automated Graphical Representations: How Model-Based Text Visualizations Facilitate Learning in Reading Comprehension Tasks  

ERIC Educational Resources Information Center

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…

Pirnay-Dummer, Pablo; Ifenthaler, Dirk

2011-01-01

274

Computer-Based Assessment in E-Learning: A Framework for Constructing "Intermediate Constraint" Questions and Tasks for Technology Platforms  

ERIC Educational Resources Information Center

Technology today offers many new opportunities for innovation in educational assessment through rich new assessment tasks and potentially powerful scoring, reporting and real-time feedback mechanisms. One potential limitation for realizing the benefits of computer-based assessment in both instructional assessment and large scale testing comes in…

Scalise, Kathleen; Gifford, Bernard

2006-01-01

275

A Dynamic Job Grouping-Based Scheduling for Deploying Applications with Fine-Grained Tasks on Global Grids  

E-print Network

A Dynamic Job Grouping-Based Scheduling for Deploying Applications with Fine-Grained Tasks for executing applications with compute-intensive jobs, there exist several applications with a large number of lightweight jobs. The overall processing undertaking of these applications involves high overhead time

Buyya, Rajkumar

276

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

E-print Network

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, ...

Valdes-Perez, Raul E.

277

Building Task-Based User Interfaces with ANSI\\/CEA2018  

Microsoft Academic Search

The recently approved ANSI\\/CEA-2018 standard is motivated by the current usability crisis in computer controlled electronic products. The standard facilitates a new user interface design methodology that uses a task model at runtime to guide users.

Charles Rich

2009-01-01

278

Trust-Based Mechanisms for Robust and Efficient Task Allocation in the Presence of Execution Uncertainty  

Microsoft Academic Search

Vickrey-Clarke-Groves (VCG) mechanisms are often used to allocate tasks to selfish and ratio- nal agents. VCG mechanisms are incentive-compatible, direct mechanisms that are efficient (i.e. maximise social utility) and individually rational (i.e. a gents prefer to join rather than opt out). However, an important assumption of these mechanisms is that the agents will always successfully complete their allocated tasks. Clearly,

Sarvapali D. Ramchurn; C. Mezzetti; Andrea Giovannucci; Juan A. Rodríguez-Aguilar; Rajdeep K. Dash; Nicholas R. Jennings

2009-01-01

279

A Community-Based Initiative to Reduce Children's Exposure to Toxics in Household Products  

ERIC Educational Resources Information Center

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…

Blackman, Anne Berlin; Luskin, Jack

2006-01-01

280

"Development of Model-Based Air Pollution Exposure Metrics for use in Epidemiologic Studies"  

EPA Science Inventory

Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

281

DEVELOPMENT OF MODEL-BASED AIR POLLUTION EXPOSURE METRICS FOR USE IN EPIDEMIOLOGIC STUDIES  

EPA Science Inventory

Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

282

Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations  

PubMed Central

This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles. PMID:22377680

Rowley, Jack T; Joyner, Ken H

2012-01-01

283

Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model  

PubMed Central

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

Wei, Binnian; Isukapalli, Sastry S.; Weisel, Clifford P.

2014-01-01

284

Approximating implicit and explicit mentalizing with two naturalistic video-based tasks in typical development and autism spectrum disorder.  

PubMed

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) participants. Although both tasks were sensitive to the social impairments of individuals with ASD, implicit mentalizing was not more dysfunctional than explicit mentalizing. In TD participants, performance on the tasks did not correlate with each other, whereas in individuals with ASD they were highly correlated. These findings suggest that implicit and explicit mentalizing processes are separable in typical development. In contrast, in individuals with ASD implicit and explicit mentalizing processes are similarly impaired and closely linked suggesting a lack of developmental specification of these processes in ASD. PMID:25267068

Rosenblau, Gabriela; Kliemann, Dorit; Heekeren, Hauke R; Dziobek, Isabel

2015-04-01

285

Task-based performance analysis of SART for digital breast tomosynthesis using signal CNR and channelised Hotelling observers  

NASA Astrophysics Data System (ADS)

In this study, we examine the performance of the simultaneous algebraic reconstruction technique (SART) for digital breast tomosynthesis under variations in key imaging parameters, such as the number of iterations, number of projections, angular range, initial guess, radiation dose, etc. We use a real breast CT volume as a ground truth digital phantom from which to simulate x-ray projections under the various selected conditions. The reconstructed image quality is measured using task-based metrics, namely signal CNR and the AUC of a Channelised Hotelling Observer with Laguerre-Gauss basis functions. The task at hand is a signal-known-exactly (SKE) task, where the objective is to detect a simulated mass inserted into the breast CT volume.

Van de Sompel, Dominique; Brady, Michael; Ho, Candy P. S.; McLennan, Andrew

2010-04-01

286

Comparative evaluation of twenty pilot workload assessment measure using a psychomotor task in a moving base aircraft simulator  

NASA Technical Reports Server (NTRS)

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.

Connor, S. A.; Wierwille, W. W.

1983-01-01

287

Health effects of gasoline exposure. I. Exposure assessment for U.S. distribution workers.  

PubMed Central

Personal exposures were estimated for a large cohort of workers in the U.S. domestic system for distributing gasoline by trucks and marine vessels. This assessment included development of a rationale and methodology for extrapolating vapor exposures prior to the availability of measurement data, analysis of existing measurement data to estimate task and job exposures during 1975-1985, and extrapolation of truck and marine job exposures before 1975. A worker's vapor exposure was extrapolated from three sets of factors: the tasks in his or her job associated with vapor sources, the characteristics of vapor sources (equipment and other facilities) at the work site, and the composition of petroleum products producing vapors. Historical data were collected on the tasks in job definitions, on work-site facilities, and on product composition. These data were used in a model to estimate the overall time-weighted-average vapor exposure for jobs based on estimates of task exposures and their duration. Task exposures were highest during tank filling in trucks and marine vessels. Measured average annual, full-shift exposures during 1975-1985 ranged from 9 to 14 ppm of total hydrocarbon vapor for truck drivers and 2 to 35 ppm for marine workers on inland waterways. Extrapolated past average exposures in truck operations were highest for truck drivers before 1965 (range 140-220 ppm). Other jobs in truck operations resulted in much lower exposures. Because there were few changes in marine operations before 1979, exposures were assumed to be the same as those measured during 1975-1985. Well-defined exposure gradients were found across jobs within time periods, which were suitable for epidemiologic analyses. PMID:8020436

Smith, T J; Hammond, S K; Wong, O

1993-01-01

288

Task-specific ionic liquid as base, ligand and reaction medium for the palladium-catalyzed Heck reaction  

Microsoft Academic Search

A novel ionic liquid, which was based on ethanolamine-functionalized quaternary ammonium salt was designed and synthesized. 4-Di(hydroxyethyl)aminobutyl tributylammonium bromide (DHEABTBAB) 1, a task-specific ionic liquid, which acts as a base, ligand and reaction medium, exhibits a very high activity and recyclability to palladium-catalyzed Heck reaction. The olefinations of iodoarenes, bromoarenes and chloroarenes with olefins generated the corresponding cross-coupling products in

Lei Wang; Hongji Li; Pinhua Li

2009-01-01

289

Application of Contact-Based Sensors for Self-Localization and Object Recognition in Humanoid Robot Navigation Tasks  

Microsoft Academic Search

This paper presents the application of a six-axis force sensor and a novel optical three-axis tactile sensor to humanoid robot navigation system which is based on contact interaction towards supporting visual-based navigation. The force sensors are mounted on humanoid robot arms to perform grasping in self-localization task to define the robot's position and orientation. The grasping results guided the robot

Hanafiah B. Yussof; Masahiro Ohka; Jumpei Takata; Mitsuhiro Yamano; Yasuo Nasu

2007-01-01

290

Pharmacological enhancement of exposure-based treatment in PTSD: a qualitative review  

PubMed Central

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

de Kleine, Rianne A.; Rothbaum, Barbara O.; van Minnen, Agnes

2013-01-01

291

PM2.5 exposure and birth outcomes: Use of satellite- and monitor-based data  

PubMed Central

Background Air pollution may be related to adverse birth outcomes. Exposure information from land-based monitoring stations often suffers from limited spatial coverage. Satellite data offer an alternative data source for exposure assessment. Methods We used birth certificate data for births in Connecticut and Massachusetts, U.S. (2000-2006). Gestational exposure to PM2.5 was estimated from US Environmental Protection Agency monitoring data and from satellite data. Satellite data were processed and modeled using 2 methods – denoted satellite (1) and satellite (2) – before exposure assessment. Regression models related PM2.5 exposure to birth outcomes while controlling for several confounders. Birth outcomes were mean birth weight at term birth, low birth weight at term (LBW <2500g), small for gestational age (SGA, <10th percentile for gestational age and sex), and preterm birth (<37 weeks). Results Overall, the exposure assessment method modified the magnitude of the effect estimates of PM2.5 on birth outcomes. Change in birth weight per inter-quartile range (2.41 ?g/m3)-increase in PM2.5 was -6g (95% confidence interval = -8 to -5), -16g (-21 to -11) and -19g (-23 to -15), using the monitor, satellite (1) and satellite (2) methods, respectively. Adjusted odds ratios, based on the same 3 exposure methods, for term LBW were 1.01 (0.98 to 1.04), 1.06 (0.97 to 1.16), and 1.08 (1.01 to 1.16); for SGA, 1.03 (1.01 to 1.04), 1.06 (1.03 to 1.10) and 1.08 (1.04 to 1.11); and for preterm birth, 1.00 (0.99 to 1.02), 0.98 (0.94 to 1.03) and 0.99 (0.95 to 1.03). Conclusions Under exposure assessment methods, we found associations between PM2.5 exposure and adverse birth outcomes particularly for birth weight among term births and for SGA. These results add to the growing concerns that air pollution adversely affects infant health and suggest that analysis of health consequences based on satellite-based exposure assessment can provide additional useful information. PMID:24240652

Hyder, Ayaz; Lee, Hyung Joo; Ebisu, Keita; Koutrakis, Petros; Belanger, Kathleen; Bell, Michelle Lee

2014-01-01

292

Cooperative scheduling of imaging observation tasks for high-altitude airships based on propagation algorithm.  

PubMed

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

Chuan, He; Dishan, Qiu; Jin, Liu

2012-01-01

293

Cooperative Scheduling of Imaging Observation Tasks for High-Altitude Airships Based on Propagation Algorithm  

PubMed Central

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

Chuan, He; Dishan, Qiu; Jin, Liu

2012-01-01

294

Public magnetic field exposure based on internal current density for electric low voltage systems.  

PubMed

A measurement concept utilizing a new magnetic field exposure metering system has been developed for indoor substations where voltage is transformed from a medium voltage of 10 or 20 kV to a low voltage of 400 V. The new metering system follows the guidelines published by the International Commission on Non-Ionizing Radiation Protection. It can be used to measure magnetic field values, total harmonic distortion of the magnetic field, magnetic field exposure ratios for public and workers, load current values, and total harmonic distortion of the load current. This paper demonstrates how exposure to non-sinusoidal magnetic fields and magnetic flux density exposure values can be compared directly with limit values for internal current densities in a human body. Further, we present how the magnetic field and magnetic field exposure behaves in the vicinity of magnetic field sources within the indoor substation and in the neighborhood. Measured magnetic fields around the substation components have been used to develop a measurement concept by which long-term measurements in the substations were performed. Long-term measurements revealed interesting and partly unexpected dependencies between the measured quantities, which have been further analyzed. The principle of this paper is to substitute a demanding exposure measurement with measurements of the basic quantities like the 50 Hz fundamental magnetic field component, which can be estimated based on the load currents for certain classes of substation lay-out. PMID:19276702

Keikko, Tommi; Seesvuori, Reino; Hyvönen, Martti; Valkealahti, Seppo

2009-04-01

295

Comparative analysis of UVB exposure between Nimbus 7/TOMS satellite estimates and ground-based measurements  

NASA Astrophysics Data System (ADS)

This study describes the patterns of variation in ultraviolet (UV) exposure across time and space using two continental scale data sets on UV radiation and conducts a comparative analysis of two sources of noontime UV-B exposure data across the continental US. One dataset was collected from 37 ground-based stations equipped with broadband UV-B-1 Pyranometers across North America whereas the other dataset was of synchronous satellite data collected from the Nimbus-7/TOMS sensor. Comparisons of these datasets confirmed agreement between the ground-based measurements and the TOMS satellite estimates with correlation coefficients of 0.87 and 0.95 for daily and monthly UV Index time series (i.e., a common metric of UV radiation exposure), respectively.

Gao, Zhiqiang; Gao, Wei

2010-08-01

296

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

PubMed Central

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

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

2015-01-01

297

Learning Effects in the Block Design Task: A Stimulus Parameter-Based Approach  

ERIC Educational Resources Information Center

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,…

Miller, Joseph C.; Ruthig, Joelle C.; Bradley, April R.; Wise, Richard A.; Pedersen, Heather A.; Ellison, Jo M.

2009-01-01

298

Text, Graphics, and Multimedia Materials Employed in Learning a Computer-Based Procedural Task  

ERIC Educational Resources Information Center

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…

Coffindaffer, Kari Christine Carlson

2010-01-01

299

Classroom-Based Functional Analysis and Intervention for Disruptive and Off-Task Behaviors  

ERIC Educational Resources Information Center

Although there is a growing body of literature on the use of functional analysis in schools, there is a need for more demonstrations of this technology being used during the course of typical instruction. In this study, we conducted functional analyses of disruptive and off-task behavior in a reading classroom setting for 3 participants of typical…

Shumate, Emily D.; Wills, Howard P.

2010-01-01

300

A survey and task-based quality assessment of static 2D colormaps  

NASA Astrophysics Data System (ADS)

Color is one of the most important visual variables since it can be combined with any other visual mapping to encode information without using additional space on the display. Encoding one or two dimensions with color is widely explored and discussed in the field. Also mapping multi-dimensional data to color is applied in a vast number of applications, either to indicate similar, or to discriminate between different elements or (multi-dimensional) structures on the screen. A variety of 2D colormaps exists in literature, covering a large variance with respect to different perceptual aspects. Many of the colormaps have a different perspective on the underlying data structure as a consequence of the various analysis tasks that exist for multivariate data. Thus, a large design space for 2D colormaps exists which makes the development and use of 2D colormaps cumbersome. According to our literature research, 2D colormaps have not been subject of in-depth quality assessment. Therefore, we present a survey of static 2D colormaps as applied for information visualization and related fields. In addition, we map seven devised quality assessment measures for 2D colormaps to seven relevant tasks for multivariate data analysis. Finally, we present the quality assessment results of the 2D colormaps with respect to the seven analysis tasks, and contribute guidelines about which colormaps to select or create for each analysis task.

Bernard, Jürgen; Steiger, Martin; Mittelstädt, Sebastian; Thum, Simon; Keim, Daniel; Kohlhammer, Jörn

2015-01-01

301

Interactional Feedback in Learner-Learner Interactions in a Task-Based EFL Classroom  

ERIC Educational Resources Information Center

This research explores learner-learner interactions (n = 18) in an authentic EFL classroom. First, we examined the nature of interactional feedback provided during two decision-making tasks. We then investigated whether the learners had made use of the feedback by looking at whether (and if so, how) they had modified their output immediately after…

Fujii, Akiko; Mackey, Alison

2009-01-01

302

Environmental support promotes expertise-based mitigation of age differences on pilot communication tasks.  

PubMed

The authors investigated whether expertise is more likely to mitigate age declines when experts rely on environmental support in a pilot/Air Traffic Control (ATC) communication task. Pilots and nonpilots listened to ATC messages that described a route through an airspace, while they referred to a chart of the airspace. They read back (repeated) each message and then answered a probe question about the route. In a preliminary study, participants could take notes while listening to the messages and performing the read-back and probe tasks. In Experiment 1, opportunity to take notes was manipulated. Note taking determined when expertise mitigated age differences on the read-back task. With note taking, read-back accuracy declined with age for nonpilots but not for pilots. Without note taking, similar age-related declines occurred for pilots and nonpilots. Benefits of expertise, younger age, and note taking occurred for probe accuracy, but mitigation did not occur. The findings suggest that older adults take advantage of a domain-relevant form of environmental support (note taking) to maintain performance on some complex tasks despite typical age-related declines in cognitive ability. PMID:12825776

Morrow, Daniel G; Ridolfo, Heather E; Menard, William E; Sanborn, Adam; Stine-Morrow, Elizabeth A L; Magnor, Cliff; Herman, Larry; Teller, Thomas; Bryant, David

2003-06-01

303

Attentional and intentional cueing in a Simon task: An EEG-based approach  

Microsoft Academic Search

Advance information about the location of a stimulus (attentional cueing) does not affect the Simon effect (a shortening of manual response times whenever the position of a stimulus that is irrelevant for the task corresponds to the side of the response). However, advance information about the side of a response (intentional cueing) enhances the Simon effect. At first sight, these

Edmund Wascher; M. Wolber

2004-01-01

304

Storyboarding: A Method for Bootstrapping the Design of Computer-Based Educational Tasks  

ERIC Educational Resources Information Center

There has been a recent call for the use of more systematic thought experiments when investigating learning. This paper presents a storyboarding method for capturing and sharing initial ideas and their evolution in the design of a mathematics learning task. The storyboards produced can be considered as "virtual data" created by thought experiments…

Jones, Ian

2008-01-01

305

Towards Generic Low Payment Mechanisms for Decentralized Task Allocation: A Learning Based Approach  

Microsoft Academic Search

We study the problem of procuring a cheap path in a disjoint path graph in which the edges belong to self interested agents. A wide range of task allocation problems can be reduced to this problem by Artur Czumaj and Amir Ronen (2004). Motivated by recent negative results regarding incentive compatible mechanisms for the problem, our focus is on non

Amir Ronen; Rina Talisman

2005-01-01

306

A General Information Quality Based Approach for Satisfying Sensor Constraints in Multirobot Tasks  

E-print Network

Yu Zhang and Lynne E. Parker Proc. of IEEE International Conference on Robotics and Automation-coupled multirobot tasks (MT) through coalitions of heterogeneous robots. However, several issues remain unad- dressed. As coalitions are formed, sensor constraints among robots are also established. For example

Parker, Lynne E.

307

Optimal GEDF-Based Schedulers that Allow Intra-Task Parallelism on Heterogeneous Multiprocessors  

E-print Network

Hill Abstract A variant of the conventional sporadic task model is con- sidered wherein successive big.LITTLE [1], which integrates relatively slower, low-power processors with faster, high-power ones faster ARM Cortex-A15 cores [2]. Using a big.LITTLE platform, en- Work supported by NSF grants CNS

Anderson, James

308

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

E-print Network

. We consider three different objectives, namely, maximizing resilience and resource utilization while, task assignment, trust, risk I. INTRODUCTION Tactical networks deployed to support military missions mission completion ratio in the presence of hostile or faulty entities (i.e., high resilience to hostility

Chen, Ing-Ray

309

Exposure to TCDD from base perimeter application of Agent Orange in Vietnam.  

PubMed

Using recognized methods routinely employed by pesticide regulatory agencies, the exposures of military personnel that were mixer/loader/applicators (M/L/A) of Agent Orange (AO) for perimeter foliage at bases during the Vietnam War were estimated. From the fraction of TCDD in AO, absorbed dosage of the manufacturing contaminant was estimated. Dermal exposure estimated from spray drift to residents of the bases was calculated using internationally recognized software that accounted for proximity, foliar density of application site, droplet size and wind speed among other factors, and produced estimates of deposition. Those that directly handled AO generally had much higher exposures than those further from the areas of use. The differences in exposure potential varied by M/L/A activity, but were typically orders of magnitude greater than bystanders. However, even the most-exposed M/L/A involved in perimeter application had lifetime exposures comparable to persons living in the U.S. at the time, i.e., ~1.3 to 5pg TCDD/kg bodyweight. PMID:25531592

Ross, John H; Hewitt, Andrew; Armitage, James; Solomon, Keith; Watkins, Deborah K; Ginevan, Michael E

2015-04-01

310

Does physiotherapy based on the Bobath concept, in conjunction with a task practice, achieve greater improvement in walking ability in people with stroke compared to physiotherapy focused on structured task practice alone? A pilot randomized controlled trial  

Microsoft Academic Search

Objective: To compare the short-term effects of two physiotherapy approaches for improving ability to walk in different environments following stroke: (i) interventions based on the Bobath concept, in conjunction with task practice, compared to (ii) structured task practice alone.Design: Randomized controlled trial.Setting: Two rehabilitation centresParticipants: Twenty-six participants between four and 20 weeks post-stroke, able to walk with supervision indoors.Interventions: Both

Kim Brock; Gerlinde Haase; Gerhard Rothacher; Susan Cotton

2011-01-01

311

Conflict tasks and the diffusion framework: Insight in model constraints based on psychological laws.  

PubMed

Formal models of decision-making have traditionally focused on simple, two-choice perceptual decisions. To date, one of the most influential account of this process is Ratcliff's drift diffusion model (DDM). However, the extension of the model to more complex decisions is not straightforward. In particular, conflicting situations, such as the Eriksen, Stroop, or Simon tasks, require control mechanisms that shield the cognitive system against distracting information. We adopted a novel strategy to constrain response time (RT) models by concurrently investigating two well-known empirical laws in conflict tasks, both at experimental and modeling levels. The two laws, predicted by the DDM, describe the relationship between mean RT and (i) target intensity (Piéron's law), (ii) standard deviation of RT (Wagenmakers-Brown's law). Pioneering work has shown that Piéron's law holds in the Stroop task, and has highlighted an additive relationship between target intensity and compatibility. We found similar results in both Eriksen and Simon tasks. Compatibility also violated Wagenmakers-Brown's law in a very similar and particular fashion in the two tasks, suggesting a common model framework. To investigate the nature of this commonality, predictions of two recent extensions of the DDM that incorporate selective attention mechanisms were simulated and compared to the experimental results. Both models predict Piéron's law and the violation of Wagenmakers-Brown's law by compatibility. Fits of the models to the RT distributions and accuracy data allowed us to further reveal their relative strengths and deficiencies. Combining experimental and computational results, this study sets the groundwork for a unified model of decision-making in conflicting environments. PMID:24762975

Servant, Mathieu; Montagnini, Anna; Burle, Borís

2014-07-01

312

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...

313

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

Microsoft Academic Search

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 culture between providers and patients. Our treatment modifications include the use of metaphors

Michael W. Otto; Devon E. Hinton

2006-01-01

314

Multimodal Exposure-Based Group Treatment for Peacekeepers With PTSD: A Preliminary Evaluation  

Microsoft Academic Search

Group therapy can effectively reduce posttraumatic stress symptoms. However, the available literature on multifaceted programs for military samples is limited and available studies typically do not evaluate outcomes on a broad range of related problems. This study describes a retrospective evaluation of a multimodal, exposure-based group treatment program for posttraumatic stress disorder (PTSD) and associated symptoms in 22 peacekeeping veterans

Arthur R. Rademaker; Eric Vermetten; Rolf J. Kleber

2009-01-01

315

Work Characteristics and Pesticide Exposures among Migrant Agricultural Families: A Community-Based Research Approach  

Microsoft Academic Search

There are few data on pesticide exposures of migrant Latino farmworker children, and access to this vulnerable population is often difficult. In this paper we describe a community-based approach to implement culturally appropriate research methods with a migrant Latino farm- worker community in Oregon. Assessments were conducted in 96 farmworker homes and 24 grower homes in two agricultural communities in

Linda A. McCauley; Michael R. Lasarev; Gregory Higgins; Joan Rothlein; Juan Muniz; Caren Ebbert; Jacki Phillips

2001-01-01

316

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

Microsoft Academic Search

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

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

2012-01-01

317

A Guide to Work-Based Learning Programs: Part II--Career Exposure. First Edition.  

ERIC Educational Resources Information Center

This guide, which is one of a series of three guides designed to provide state and local leaders, policymakers, practitioners, and other stakeholders with information about the work-based learning component of the School to Work Opportunities Act, deals with career exposure. The introduction traces the history of school-to-work initiatives, lists…

Ingham Intermediate School District, Mason, MI.

318

POTENTIAL INHALATION EXPOSURE TO VOLATILE CHEMICALS IN WATER-BASED HARD-SURFACE CLEANERS  

EPA Science Inventory

Potential inhalation exposure of building occupants to volatile chemicals in water-based hard-surface cleaners was evaluated by analyzing 267 material safety data sheets (MSDSs). Among the 154 chemicals reported, 44 are volatile or semi-volatile. Hazardous air pollutants (HAPs) r...

319

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

PubMed Central

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

2012-01-01

320

Task shifting for tuberculosis control: A qualitative study of community-based directly observed therapy in urban Uganda  

PubMed Central

This qualitative study of task shifting examined tuberculosis (TB) therapy under modified community-based directly observed treatment short-course (CB-DOTS) in Kampala, Uganda. New TB patients selected one of two strategies: home-based DOTS and clinic-based DOTS. Relevant socio-economic characteristics, treatment-seeking experiences and outcomes were assessed over eight months of follow-up. Of 107 patients recruited, 89 (83%) selected home-based DOTS. Sixty-two patients (70%) under home-based DOTS and 16 patients (89%) under clinic-based DOTS had successful outcomes following completion of tuberculosis therapy. Treatment supporters’ provision of social support beyond observing drug ingestion contributed to successful outcomes under both strategies. Home-based DOTS provides continuity of social support during therapy, strengthening the potential for treatment success. Conventional health facility–based DOTS can be modified in resource-limited urban Africa to offer a viable DOTS strategy that is sensitive to personal preference. Shifting the task of DOTS support away from only qualified health workers to include laypersons in the patients’ social-support network may contribute to meeting World Health Organization (WHO) treatment targets. We recommend an intervention evaluating this modified DOTS strategy on a larger scale in TB high-burden, resource-poor urban settings. PMID:21360381

Mafigiri, David K.; Mcgrath, Janet W.; Whalen, Christopher C.

2013-01-01

321

NCI-FDA Interagency Oncology Task Force Workshop Provides Guidance for Analytical Validation of Protein-based Multiplex Assays  

Cancer.gov

An NCI-FDA Interagency Oncology Task Force (IOTF) Molecular Diagnostics Workshop was held on October 30, 2008 in Cambridge, MA, to discuss requirements for analytical validation of protein-based multiplex technologies in the context of its intended use. This workshop developed through NCI's Clinical Proteomic Technologies for Cancer initiative and the FDA focused on technology-specific analytical validation processes to be addressed prior to use in clinical settings.

322

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

Microsoft Academic Search

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 Sr2+ from aqueous solutions has been evaluated. The extraction properties of these TSILs can be influenced by the structures of the covalently

Huimin Luo; Sheng Dai; Peter V. Bonnesen; A BUCHANANIII

2006-01-01

323

The effect of task-based instruction on the acquisition and use of English existential constructions by Iranian EFL learners  

Microsoft Academic Search

This study sought to measure the degree of students’ success in learning and proper use of Existential Constructions (ECs), namely there is\\/are, in English as a foreign language through Focus on Form (FonF) techniques in Task-based language teaching. For this purpose, 60 Iranian learners of English were randomly selected and assigned to one experimental and two control groups. Analysis of

Hussein Muhammadi Farsani; Mansour Tavakoli; Ahmad Moinzadeh

2012-01-01

324

The effect of task-based instruction on the acquisition and use of English existential constructions by Iranian EFL learners  

Microsoft Academic Search

This study sought to measure the degree of students' success in learning and proper use of Existential Constructions (ECs), namely there is\\/are, in English as a foreign language through Focus on Form (FonF) techniques in Task-based language teaching. For this purpose, 60 Iranian learners of English were randomly selected and assigned to one experimental and two control groups. Analysis of

Hussein Muhammadi Farsani; Mansour Tavakoli; Ahmad Moinzadeh

2011-01-01

325

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...

326

An empirical analysis of exposure-based regulation to abate toxic air pollution  

SciTech Connect

Title III of the 1990 Clean Air Act Amendments requires the Environmental Protection Agency to regulate 189 air toxics, including emissions from by-product coke ovens. Economists criticize the inefficiency of uniform standards, but Title III makes no provision for flexible regulatory instruments. Environmental health scientists suggest that population exposure, not necessarily ambient air quality, should motivate environmental air pollution policies. Using an engineering-economic model of the United States steel industry, we estimate that an exposure-based policy can achieve the same level of public health as coke oven emissions standards and can reduce compliance costs by up to 60.0%. 18 refs., 3 figs., 1 tab.

Marakovits, D.M.; Considine, T.J. [Pennsylvania State Univ., University Park, PA (United States)] [Pennsylvania State Univ., University Park, PA (United States)

1996-11-01

327

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

PubMed

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

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

2014-11-01

328

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

PubMed Central

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

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

2011-01-01

329

Comparing Response Time, Errors, and Satisfaction Between Text-based and Graphical User Interfaces During Nursing Order Tasks  

PubMed Central

Despite the general adoption of graphical users interfaces (GUIs) in health care, few empirical data document the impact of this move on system users. This study compares two distinctly different user interfaces, a legacy text-based interface and a prototype graphical interface, for differences in nurses' response time (RT), errors, and satisfaction when the interfaces are used in the performance of computerized nursing order tasks. In a medical center on the East Coast of the United States, 98 randomly selected male and female nurses completed 40 tasks using each interface. Nurses completed four different types of order tasks (create, activate, modify, and discontinue). Using a repeated-measures and Latin square design, the study was counterbalanced for tasks, interface types, and blocks of trials. Overall, nurses had significantly faster response times (P < 0.0001) and fewer errors (P < 0.0001) using the prototype GUI than the text-based interface. The GUI was also rated significantly higher for satisfaction than the text system, and the GUI was faster to learn (P < 0.0001). Therefore, the results indicated that the use of a prototype GUI for nursing orders significantly enhances user performance and satisfaction. Consideration should be given to redesigning older user interfaces to create more modern ones by using human factors principles and input from user-centered focus groups. Future work should examine prospective nursing interfaces for highly complex interactions in computer-based patient records, detail the severity of errors made on line, and explore designs to optimize interactions in life-critical systems. PMID:10730600

Staggers, Nancy; Kobus, David

2000-01-01

330

Comparing response time, errors, and satisfaction between text-based and graphical user interfaces during nursing order tasks.  

PubMed

Despite the general adoption of graphical users interfaces (GUIs) in health care, few empirical data document the impact of this move on system users. This study compares two distinctly different user interfaces, a legacy text-based interface and a prototype graphical interface, for differences in nurses' response time (RT), errors, and satisfaction when the interfaces are used in the performance of computerized nursing order tasks. In a medical center on the East Coast of the United States, 98 randomly selected male and female nurses completed 40 tasks using each interface. Nurses completed four different types of order tasks (create, activate, modify, and discontinue). Using a repeated-measures and Latin square design, the study was counterbalanced for tasks, interface types, and blocks of trials. Overall, nurses had significantly faster response times (P < 0.0001) and fewer errors (P < 0.0001) using the prototype GUI than the text-based interface. The GUI was also rated significantly higher for satisfaction than the text system, and the GUI was faster to leam (P < 0.0001). Therefore, the results indicated that the use of a prototype GUI for nursing orders significantly enhances user performance and satisfaction. Consideration should be given to redesigning older user interfaces to create more modern ones by using human factors principles and input from user-centered focus groups. Future work should examine prospective nursing interfaces for highly complex interactions in computer-based patient records, detail the severity of errors made on line, and explore designs to optimize interactions in life-critical systems. PMID:10730600

Staggers, N; Kobus, D

2000-01-01

331

Simulator-based study of human errors in nuclear power plant control room tasks  

Microsoft Academic Search

The purposes of this study were to empirically establish error rates for control selection and operation during the performance of proceduralized tasks in nuclear power plant control rooms during simulated casualties, and to compare the observed error rates with the human error probabilities (HEPs) presented in NUREG\\/CR-1278. Data were collected at full-scale, high-fidelity simulators from licensed operators undergoing requalification training

A. N. Beare; R. E. Dorris; C. R. Bovell; D. S. Crowe; E. J. Kozinsky

1984-01-01

332

Application of multi-task design method based on linux for PET real-time control  

Microsoft Academic Search

A multi-task framework proposed for PET (positron emission tomography) equipment on the basic principle of real-time system analysis is used to develop PET real-time control system. With the realization of the software part particularly detailed, the system flow chart of the software part is introduced. Then, those mechanic subsystems including scanner bed, rod source, septa and wobble are all verified

Yongfu Wang; Hong Zhao; Jiren Liu; Tianyou Chai

2008-01-01

333

Task-based vehicle interior layout design using optimization method to enhance safety  

NASA Astrophysics Data System (ADS)

This paper presents a virtual environment for conducting vehicle interior layout design. A virtual human called Santos that is biomechanically correct, has realistic musculoskeletal system, and natural motion/posture is created to live in this virtual world. One of the objectives of this virtual environment is to allow Santos to explore the interior package design such that one designs new defense and security vehicles without having to create a physical prototype to enhance safety, save time and cost. Different controls require different tasks, for example, pulling a clutch lever, pushing a button, turning a knob, and so on. Therefore, different tasks correspond to different human upper-body motions and hand loads, which in turn correspond to different displacement and torque at each joint. This is a dynamics problem for interior layout design with external loads. The formulation of dynamic equations of motion is implemented within optimization algorithm to predict joint profiles. This methodology allows Santos to help vehicle interior layout design while executing various tasks.

Kim, Joo; Yang, Jingzhou; Abdel-Malek, Karim; Nebel, Kyle

2005-05-01

334

Cross-shift changes in FEV1 in relation to wood dust exposure: the implications of different exposure assessment methods  

PubMed Central

Background: Exposure-response analyses in occupational studies rely on the ability to distinguish workers with regard to exposures of interest. Aims: To evaluate different estimates of current average exposure in an exposure-response analysis on dust exposure and cross-shift decline in FEV1 among woodworkers. Methods: Personal dust samples (n = 2181) as well as data on lung function parameters were available for 1560 woodworkers from 54 furniture industries. The exposure to wood dust for each worker was calculated in eight different ways using individual measurements, group based exposure estimates, a weighted estimate of individual and group based exposure estimates, and predicted values from mixed models. Exposure-response relations on cross-shift changes in FEV1 and exposure estimates were explored. Results: A positive exposure-response relation between average dust exposure and cross-shift FEV1 was shown for non-smokers only and appeared to be most pronounced among pine workers. In general, the highest slope and standard error (SE) was revealed for grouping by a combination of task and factory size, the lowest slope and SE was revealed for estimates based on individual measurements, with the weighted estimate and the predicted values in between. Grouping by quintiles of average exposure for task and factory combinations revealed low slopes and high SE, despite a high contrast. Conclusion: For non-smokers, average dust exposure and cross-shift FEV1 were associated in an exposure dependent manner, especially among pine workers. This study confirms the consequences of using different exposure assessment strategies studying exposure-response relations. It is possible to optimise exposure assessment combining information from individual and group based exposure estimates, for instance by applying predicted values from mixed effects models. PMID:15377768

Schlunssen, V; Sigsgaard, T; Schaumburg, I; Kromhout, H

2004-01-01

335

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

SciTech Connect

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).

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

336

Biological and health effects of exposure to kerosene-based jet fuels and performance additives.  

PubMed

Over 2 million military and civilian personnel per year (over 1 million in the United States) are occupationally exposed, respectively, to jet propulsion fuel-8 (JP-8), JP-8 +100 or JP-5, or to the civil aviation equivalents Jet A or Jet A-1. Approximately 60 billion gallon of these kerosene-based jet fuels are annually consumed worldwide (26 billion gallon in the United States), including over 5 billion gallon of JP-8 by the militaries of the United States and other NATO countries. JP-8, for example, represents the largest single chemical exposure in the U.S. military (2.53 billion gallon in 2000), while Jet A and A-1 are among the most common sources of nonmilitary occupational chemical exposure. Although more recent figures were not available, approximately 4.06 billion gallon of kerosene per se were consumed in the United States in 1990 (IARC, 1992). These exposures may occur repeatedly to raw fuel, vapor phase, aerosol phase, or fuel combustion exhaust by dermal absorption, pulmonary inhalation, or oral ingestion routes. Additionally, the public may be repeatedly exposed to lower levels of jet fuel vapor/aerosol or to fuel combustion products through atmospheric contamination, or to raw fuel constituents by contact with contaminated groundwater or soil. Kerosene-based hydrocarbon fuels are complex mixtures of up to 260+ aliphatic and aromatic hydrocarbon compounds (C(6) -C(17+); possibly 2000+ isomeric forms), including varying concentrations of potential toxicants such as benzene, n-hexane, toluene, xylenes, trimethylpentane, methoxyethanol, naphthalenes (including polycyclic aromatic hydrocarbons [PAHs], and certain other C(9)-C(12) fractions (i.e., n-propylbenzene, trimethylbenzene isomers). While hydrocarbon fuel exposures occur typically at concentrations below current permissible exposure limits (PELs) for the parent fuel or its constituent chemicals, it is unknown whether additive or synergistic interactions among hydrocarbon constituents, up to six performance additives, and other environmental exposure factors may result in unpredicted toxicity. While there is little epidemiological evidence for fuel-induced death, cancer, or other serious organic disease in fuel-exposed workers, large numbers of self-reported health complaints in this cohort appear to justify study of more subtle health consequences. A number of recently published studies reported acute or persisting biological or health effects from acute, subchronic, or chronic exposure of humans or animals to kerosene-based hydrocarbon fuels, to constituent chemicals of these fuels, or to fuel combustion products. This review provides an in-depth summary of human, animal, and in vitro studies of biological or health effects from exposure to JP-8, JP-8 +100, JP-5, Jet A, Jet A-1, or kerosene. PMID:12775519

Ritchie, Glenn; Still, Kenneth; Rossi, John; Bekkedal, Marni; Bobb, Andrew; Arfsten, Darryl

2003-01-01

337

Task-based image quality evaluation of iterative reconstruction methods for low dose CT using computer simulations.  

PubMed

Iterative reconstruction (IR) methods for x-ray CT is a promising approach to improve image quality or reduce radiation dose to patients. The goal of this work was to use task based image quality measures and the channelized Hotelling observer (CHO) to evaluate both analytic and IR methods for clinical x-ray CT applications. We performed realistic computer simulations at five radiation dose levels, from a clinical reference low dose D0 to 25% D0. A fixed size and contrast lesion was inserted at different locations into the liver of the XCAT phantom to simulate a weak signal. The simulated data were reconstructed on a commercial CT scanner (SOMATOM Definition Flash; Siemens, Forchheim, Germany) using the vendor-provided analytic (WFBP) and IR (SAFIRE) methods. The reconstructed images were analyzed by CHOs with both rotationally symmetric (RS) and rotationally oriented (RO) channels, and with different numbers of lesion locations (5, 10, and 20) in a signal known exactly (SKE), background known exactly but variable (BKEV) detection task. The area under the receiver operating characteristic curve (AUC) was used as a summary measure to compare the IR and analytic methods; the AUC was also used as the equal performance criterion to derive the potential dose reduction factor of IR. In general, there was a good agreement in the relative AUC values of different reconstruction methods using CHOs with RS and RO channels, although the CHO with RO channels achieved higher AUCs than RS channels. The improvement of IR over analytic methods depends on the dose level. The reference dose level D0 was based on a clinical low dose protocol, lower than the standard dose due to the use of IR methods. At 75% D0, the performance improvement was statistically significant (p < 0.05). The potential dose reduction factor also depended on the detection task. For the SKE/BKEV task involving 10 lesion locations, a dose reduction of at least 25% from D0 was achieved. PMID:25776521

Xu, Jingyan; Fuld, Matthew K; Fung, George S K; Tsui, Benjamin M W

2015-04-01

338

Task-based image quality evaluation of iterative reconstruction methods for low dose CT using computer simulations  

NASA Astrophysics Data System (ADS)

Iterative reconstruction (IR) methods for x-ray CT is a promising approach to improve image quality or reduce radiation dose to patients. The goal of this work was to use task based image quality measures and the channelized Hotelling observer (CHO) to evaluate both analytic and IR methods for clinical x-ray CT applications. We performed realistic computer simulations at five radiation dose levels, from a clinical reference low dose D0 to 25% D0. A fixed size and contrast lesion was inserted at different locations into the liver of the XCAT phantom to simulate a weak signal. The simulated data were reconstructed on a commercial CT scanner (SOMATOM Definition Flash; Siemens, Forchheim, Germany) using the vendor-provided analytic (WFBP) and IR (SAFIRE) methods. The reconstructed images were analyzed by CHOs with both rotationally symmetric (RS) and rotationally oriented (RO) channels, and with different numbers of lesion locations (5, 10, and 20) in a signal known exactly (SKE), background known exactly but variable (BKEV) detection task. The area under the receiver operating characteristic curve (AUC) was used as a summary measure to compare the IR and analytic methods; the AUC was also used as the equal performance criterion to derive the potential dose reduction factor of IR. In general, there was a good agreement in the relative AUC values of different reconstruction methods using CHOs with RS and RO channels, although the CHO with RO channels achieved higher AUCs than RS channels. The improvement of IR over analytic methods depends on the dose level. The reference dose level D0 was based on a clinical low dose protocol, lower than the standard dose due to the use of IR methods. At 75% D0, the performance improvement was statistically significant (p < 0.05). The potential dose reduction factor also depended on the detection task. For the SKE/BKEV task involving 10 lesion locations, a dose reduction of at least 25% from D0 was achieved.

Xu, Jingyan; Fuld, Matthew K.; Fung, George S. K.; Tsui, Benjamin M. W.

2015-04-01

339

A liquid crystal-based passive badge for personal monitoring of exposure to hydrogen sulfide.  

PubMed

A new liquid crystal (LC)-based passive dosimeter badge for personal monitoring of exposure to hydrogen sulfide (H2S) gas is reported. When a thin film of LC supported on a surface functionalized with lead perchlorate Pb(ClO4)2 (the LC sensor) is exposed to H2S, the orientation of LC molecules in the film changes from perpendicular to parallel. This reorientation induces a change in the appearance of the LC film when viewed between crossed polarizers. A H2S dosimeter was fabricated by pairing a LC sensor with a glass substrate forming a headspace between the two surfaces, to control diffusion of H2S across the LC film. When the dosimeter is exposed to H2S, a bright front appears as a function of exposure time. An algorithm has been developed to correlate this response length and exposure dose. The dosimeters are functionally stable when subjected to extreme temperature and humidity fluctuations, and are immune to a number of potentially interfering chemicals, except mercaptans. These dosimeters detect H2S at 0.2 ppm TWA (8 hr) with ±20% overall accuracy. The dosimeters were used to monitor the personal exposure of personnel working in an oil refinery. The TWA concentrations measured by the LC-based dosimeters correlate strongly with the NIOSH 1063 method that uses a sorbent tube and a pump followed by laboratory analysis. Thus, the LC-based dosimeters can provide a sensitive tool for on-site assessment of personal exposure to H2S in different environments. PMID:24766440

Robinson, Sheila E; Grinwald, Bart A; Bremer, Laura L; Kupcho, Kurt A; Acharya, Bharat R; Owens, Patrick D

2014-01-01

340

Errorless Embedding for Children with On-Task and Conduct Difficulties: Rapport-Based, Success-Focused Intervention in the Classroom  

ERIC Educational Resources Information Center

Children exposed to psychosocial stressors often develop behavior disorders that include off-task responding in the classroom. We used errorless embedding, a rapport-based, nonpunitive intervention, to improve on-task behavior in such children. In a multiple-baseline across subjects design, we observed 5 children with severe behavioral…

Ducharme, Joseph M.; Harris, Kimberly E.

2005-01-01

341

Work routinization and implications for ergonomic exposure assessment.  

PubMed

Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels. PMID:16393801

Gold, Judith E; Park, Jung-Soon; Punnett, Laura

2006-01-15

342

Task-based imaging of colon cancer in the ApcMin/+ mouse model  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT), laser-induced fluorescence (LIF), and laser-scanning confocal microscopy (LSCM) were used for the task of multimodal study of healthy and adenomatous mouse colon. The results from each modality were compared with histology, which served as the gold standard. The ApcMin/+ genetic mouse model of colon cancer was compared with wild-type mice. In addition, a special diet was used for the task of studying the origins of a 680 nm autofluorescent signal that was previously observed in colon. The study found close agreement among each of the modalities and with histology. All four modalities were capable of identifying diseased tissue accurately. The OCT and LSCM images provided complementary structural information about the tissue, while the autofluorescence signal measured by LIF and LSCM provided biochemical information. OCT and LIF were performed in vivo and nondestructively, while the LSCM and histology required extraction of the tissue. The magnitude of the 680 nm signal correlates with chlorophyll content in the mouse diet, suggesting that the autofluorescent compound is a dietary metabolite.

McNally, James B.; Kirkpatrick, Nathaniel D.; Hariri, Lida P.; Tumlinson, Alexandre R.; Besselsen, David G.; Gerner, Eugene W.; Utzinger, Urs; Barton, Jennifer K.

2006-05-01

343

ACE16k based stand-alone system for real-time pre-processing tasks  

NASA Astrophysics Data System (ADS)

This paper describes the design of a programmable stand-alone system for real time vision pre-processing tasks. The system's architecture has been implemented and tested using an ACE16k chip and a Xilinx xc4028xl FPGA. The ACE16k chip consists basically of an array of 128x128 identical mixed-signal processing units, locally interacting, which operate in accordance with single instruction multiple data (SIMD) computing architectures and has been designed for high speed image pre-processing tasks requiring moderate accuracy levels (7 bits). The input images are acquired using the optical input capabilities of the ACE16k chip, and after being processed according to a programmed algorithm, the images are represented at real time on a TFT screen. The system is designed to store and run different algorithms and to allow changes and improvements. Its main board includes a digital core, implemented on a Xilinx 4028 Series FPGA, which comprises a custom programmable Control Unit, a digital monochrome PAL video generator and an image memory selector. Video SRAM chips are included to store and access images processed by the ACE16k. Two daughter boards hold the program SRAM and a video DAC-mixer card is used to generate composite analog video signal.

Carranza, Luis; Jimenez-Garrido, Francisco; Linan-Cembrano, Gustavo; Roca, Elisenda; Espejo Meana, Servando; Rodriguez-Vazquez, Angel

2005-06-01

344

AutomaDeD: Automata-Based Debugging for Dissimilar Parallel Tasks  

SciTech Connect

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.

Bronevetsky, G; Laguna, I; Bagchi, S; de Supinski, B R; Ahn, D; Schulz, M

2010-03-23

345

Odor Valence Linearly Modulates Attractiveness, but Not Age Assessment, of Invariant Facial Features in a Memory-Based Rating Task  

PubMed Central

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

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

2014-01-01

346

Nursing research in community-based approaches to reduce exposure to secondhand smoke.  

PubMed

Secondhand smoke (SHS) is the third leading cause of preventable death in the United States and a major source of indoor air pollution, accounting for an estimated 53,000 deaths per year among nonsmokers. Secondhand smoke exposure varies by gender, race/ethnicity, and socioeconomic status. The most effective public health intervention to reduce SHS exposure is to implement and enforce smoke-free workplace policies that protect entire populations including all workers regardless of occupation, race/ethnicity, gender, age, and socioeconomic status. This chapter summarizes community and population-based nursing research to reduce SHS exposure. Most of the nursing research in this area has been policy outcome studies, documenting improvement in indoor air quality, worker's health, public opinion, and reduction in Emergency Department visits for asthma, acute myocardial infarction among women, and adult smoking prevalence. These findings suggest a differential health effect by strength of law. Further, smoke-free laws do not harm business or employee turnover, nor are revenues from charitable gaming affected. Additionally, smoke-free laws may eventually have a positive effect on cessation among adults. There is emerging nursing science exploring the link between SHS exposure to nicotine and tobacco dependence, suggesting one reason that SHS reduction is a quit smoking strategy. Other nursing research studies address community readiness for smoke-free policy, and examine factors that build capacity for smoke-free policy. Emerging trends in the field include tobacco free health care and college campuses. A growing body of nursing research provides an excellent opportunity to conduct and participate in community and population-based research to reduce SHS exposure for both vulnerable populations and society at large. PMID:20192112

Hahn, Ellen J; Ashford, Kristin B; Okoli, Chizimuzo T C; Rayens, Mary Kay; Ridner, S Lee; York, Nancy L

2009-01-01

347

Exposures to Lead-Based Paint Dust in an Inner-City High School  

Microsoft Academic Search

In response to concerns about lead-based paint (LBP) in an 85-year old high school, an evaluation was conducted to determine whether a lead exposure hazard existed for adult school staff. Deteriorating LBP was present on walls and ceilings throughout the school. At the time of the evaluation, abatement of LBP had been completed in approximately one-third of the school. One-hundred

John A. Decker; Robert Malkin; Max Kiefer

1999-01-01

348

Changes in Mindfulness and Emotion Regulation in an Exposure-Based Cognitive Therapy for Depression  

Microsoft Academic Search

With the mounting evidence for mindfulness training as a promising strategy for distress reduction across clinical and nonclinical\\u000a populations, it is important to learn more about the kinds of changes associated with this training. In an exposure-based\\u000a cognitive therapy for depression that includes mindfulness training, participants reported significant increases in mindfulness\\u000a over the course of therapy. Hierarchical linear modeling revealed

Sameet Kumar; Greg Feldman; Adele Hayes

2008-01-01

349

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

PubMed

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

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

2014-02-01

350

Base camp personnel exposure to particulate matter during wildland fire suppression activities.  

PubMed

Wildland fire base camps commonly house thousands of support personnel for weeks at a time. The selection of the location of these base camps is largely a strategic decision that incorporates many factors, one of which is the potential impact of biomass smoke from the nearby fire event. Biomass smoke has many documented adverse health effects due, primarily, to high levels of fine particulate matter (PM(2.5)). Minimizing particulate matter exposure to potentially susceptible individuals working as support personnel in the base camp is vital. In addition to smoke from nearby wildland fires, base camp operations have the potential to generate particulate matter via vehicle emissions, dust, and generator use. We monitored particulate matter at three base camps during the fire season of 2009 in Washington, Oregon, and California. During the sampling events, 1-min time-weighted averages of PM(2.5) and particle counts from three size fractions (0.3-0.5 microns, 0.5-1.0 microns, and 1.0-2.5 microns) were measured. Results showed that all PM size fractions (as well as overall PM(2.5) concentrations) were higher during the overnight hours, a trend that was consistent at all camps. Our results provide evidence of camp-based, site-specific sources of PM(2.5) that could potentially exceed the contributions from the nearby wildfire. These exposures could adversely impact wildland firefighters who sleep in the camp, as well as the camp support personnel, who could include susceptible individuals. A better understanding of the sources and patterns of poor air quality within base camps would help to inform prevention strategies to reduce personnel exposures. PMID:22364357

McNamara, Marcy L; Semmens, Erin O; Gaskill, Steven; Palmer, Charles; Noonan, Curtis W; Ward, Tony J

2012-01-01

351

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

SciTech Connect

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.

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

2005-01-01

352

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

PubMed Central

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

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

2014-01-01

353

Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling.  

PubMed

In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information-inside hotspots or in search of them-based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km2. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. PMID:23759207

Aerts, Sam; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

2013-10-01

354

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

PubMed Central

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

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

2014-01-01

355

Time Averaged Transmitter Power and Exposure to Electromagnetic Fields from Mobile Phone Base Stations  

PubMed Central

Models for exposure assessment of high frequency electromagnetic fields from mobile phone base stations need the technical data of the base stations as input. One of these parameters, the Equivalent Radiated Power (ERP), is a time-varying quantity, depending on communication traffic. In order to determine temporal averages of the exposure, corresponding averages of the ERP have to be available. These can be determined as duty factors, the ratios of the time-averaged power to the maximum output power according to the transmitter setting. We determine duty factors for UMTS from the data of 37 base stations in the Swisscom network. The UMTS base stations sample contains sites from different regions of Switzerland and also different site types (rural/suburban/urban/hotspot). Averaged over all regions and site types, a UMTS duty factor F ? 0.32 ± 0.08 for the 24 h-average is obtained, i.e., the average output power corresponds to about a third of the maximum power. We also give duty factors for GSM based on simple approximations and a lower limit for LTE estimated from the base load on the signalling channels. PMID:25105551

Bürgi, Alfred; Scanferla, Damiano; Lehmann, Hugo

2014-01-01

356

Time averaged transmitter power and exposure to electromagnetic fields from mobile phone base stations.  

PubMed

Models for exposure assessment of high frequency electromagnetic fields from mobile phone base stations need the technical data of the base stations as input. One of these parameters, the Equivalent Radiated Power (ERP), is a time-varying quantity, depending on communication traffic. In order to determine temporal averages of the exposure, corresponding averages of the ERP have to be available. These can be determined as duty factors, the ratios of the time-averaged power to the maximum output power according to the transmitter setting. We determine duty factors for UMTS from the data of 37 base stations in the Swisscom network. The UMTS base stations sample contains sites from different regions of Switzerland and also different site types (rural/suburban/urban/hotspot). Averaged over all regions and site types, a UMTS duty factor for the 24 h-average is obtained, i.e., the average output power corresponds to about a third of the maximum power. We also give duty factors for GSM based on simple approximations and a lower limit for LTE estimated from the base load on the signalling channels. PMID:25105551

Bürgi, Alfred; Scanferla, Damiano; Lehmann, Hugo

2014-08-01

357

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

PubMed

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

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

1994-09-01

358

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

PubMed

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

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

2014-07-01

359

Validity Assessment of Self-Reported Construction Tasks  

Microsoft Academic Search

This study assessed agreement between workers’ and observers’ daily estimates of exposure to construction work tasks. The ultimate aimwas to develop a valid method and instrument for the collection of self-reported data on duration of exposure to a priori identified work tasks for use in characterizing exposure in settings with substantial task variability. Forty-nine shop workers and 52 construction site

Katherine L. Hunting; Elizabeth Haile; Lisa Nessel; Laura S. Welch

2010-01-01

360

Setting safe acute exposure limits for halon replacement chemicals using physiologically based pharmacokinetic modeling.  

PubMed

Most proposed replacements for Halon 1301 as a fire suppressant are halogenated hydrocarbons. The acute toxic endpoint of concern for these agents is cardiac sensitization. An approach is described that links the cardiac endpoint as assessed in dogs to a target arterial concentration in humans. Linkage was made using a physiologically based pharmacokinetic (PBPK) model. Monte Carlo simulations, which account for population variability, were used to establish safe exposure times at different exposure concentrations for Halon 1301 (bromotrifluoromethane), CF(3)I (trifluoroiodomethane), HFC-125 (pentafluoroethane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (1,1,1,3,3,3-hexafluoropropane). Application of the modeling technique described here not only makes use of the conservative cardiac sensitization endpoint, but also uses an understanding of the pharmacokinetics of the chemical agents to better establish standards for safe exposure. The combined application of cardiac sensitization data and physiologically based modeling provides a quantitative approach, which can facilitate the selection and effective use of halon replacement candidates. PMID:10880155

Vinegar, A; Jepson, G W; Cisneros, M; Rubenstein, R; Brock, W J

2000-08-01

361

Ghost detection and removal based on super-pixel grouping in exposure fusion  

NASA Astrophysics Data System (ADS)

A novel multi-exposure images fusion method for dynamic scenes is proposed. The commonly used techniques for high dynamic range (HDR) imaging are based on the combination of multiple differently exposed images of the same scene. The drawback of these methods is that ghosting artifacts will be introduced into the final HDR image if the scene is not static. In this paper, a super-pixel grouping based method is proposed to detect the ghost in the image sequences. We introduce the zero mean normalized cross correlation (ZNCC) as a measure of similarity between a given exposure image and the reference. The calculation of ZNCC is implemented in super-pixel level, and the super-pixels which have low correlation with the reference are excluded by adjusting the weight maps for fusion. Without any prior information on camera response function or exposure settings, the proposed method generates low dynamic range (LDR) images which can be shown on conventional display devices directly with details preserving and ghost effects reduced. Experimental results show that the proposed method generates high quality images which have less ghost artifacts and provide a better visual quality than previous approaches.

Jiang, Shenyu; Xu, Zhihai; Li, Qi; Chen, Yueting; Feng, Huajun

2014-09-01

362

Workgroup report: base stations and wireless networks-radiofrequency (RF) exposures and health consequences.  

PubMed

Radiofrequency (RF) waves have long been used for different types of information exchange via the air waves--wireless Morse code, radio, television, and wireless telephone (i.e., construction and operation of telephones or telephone 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 telephone and base stations are not likely to adversely affect human health. PMID:17431492

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

2007-03-01

363

Near-Infrared Spectroscopy during the Verbal Fluency Task before and after Treatment with Image Exposure and SSRI Therapy in Patients with Obsessive-Compulsive Disorder  

PubMed Central

Drug therapy with selective serotonin reuptake inhibitors (SSRIs) has been used as a treatment for obsessive-compulsive disorder (OCD). In the present case report, exposure therapy was used in addition to escitalopram (20?mg) to treat a 28-year-old female patient with OCD for 6 months. Her obsessive-compulsive symptoms comprised thoughts of words such as rape, crematorium, neck hanging, unhappy, death, die, and kill and images such as a shelf of gods, a shrine, a Buddhist altar, the sun, the sky, and the faces of her parents, siblings, and relatives. As exposure therapy, she was asked to view the images associated with these symptoms three times a day along with drug therapy. With the combination of drug and exposure therapies, her obsessive-compulsive symptoms improved within 6 months, with no interference in her daily life. Multichannel near-infrared spectroscopy (NIRS) showed improvement of brain function in the temporal and frontal lobes after treatment. These results suggest that NIRS can be used as an indicator of brain function improvement in patients with OCD. PMID:25317351

Nakanishi, Mari; Tanaka, Yoshihiro; Inoue, Ayako; Kawashima, Chiwa; Okamoto, Kana; Kobayashi, Shunsuke; Ishitobi, Yoshinobu; Ninomiya, Taiga

2014-01-01

364

A pilot study of an exposure-based intervention in the ED designed to prevent posttraumatic stress disorder  

Microsoft Academic Search

Early interventions to prevent PTSD have been limited in scope and effectiveness. This pilot study examines the feasibility and preliminary effectiveness of a model for brief preventive intervention: 1-session individualized exposure-based therapy delivered in the emergency department (ED). Eligible patients who experienced exposure to a traumatic event in the previous 24 hours were screened and assigned to assessment-only (n =

Barbara Olasov Rothbaum; Debra Houry; Mary Heekin; Amy Selvig Leiner; Jill Daugherty; L. Shakiyla Smith; Maryrose Gerardi

2008-01-01

365

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

366

Disparities in Secondhand Smoke Exposure: Using TUS in a "non-ATS" state to Build Support for Evidence Based Policy  

Cancer.gov

Disparities in Secondhand Smoke Exposure: Using TUS in a “non-ATS” state to Build Support for Evidence Based Policy Sally Herndon Malek, MPH Marcus Plescia, MD MPH NC Division of Public Health Don Shopland, PHS Retired Goal: Eliminate Exposure to

367

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

Microsoft Academic Search

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

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

368

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

PubMed Central

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

2012-01-01

369

Association between arsenic exposure and plasma cholinesterase activity: a population based study in Bangladesh  

PubMed Central

Background Arsenic is a potent pollutant that has caused an environmental catastrophe in certain parts of the world including Bangladesh where millions of people are presently at risk due to drinking water contaminated by arsenic. Chronic arsenic exposure has been scientifically shown as a cause for liver damage, cancers, neurological disorders and several other ailments. The relationship between plasma cholinesterase (PChE) activity and arsenic exposure has not yet been clearly documented. However, decreased PChE activity has been found in patients suffering liver dysfunction, heart attack, cancer metastasis and neurotoxicity. Therefore, in this study, we evaluated the PChE activity in individuals exposed to arsenic via drinking water in Bangladesh. Methods A total of 141 Bangladeshi residents living in arsenic endemic areas with the mean arsenic exposure of 14.10 ± 3.27 years were selected as study subjects and split into tertile groups based on three water arsenic concentrations: low (< 129 ?g/L), medium (130-264 ?g/L) and high (> 265 ?g/L). Study subjects were further sub-divided into two groups (?50 ?g/L and > 50 ?g/L) based on the recommended upper limit of water arsenic concentration (50 ?g/L) in Bangladesh. Blood samples were collected from the study subjects by venipuncture and arsenic concentrations in drinking water, hair and nail samples were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PChE activity was assayed by spectrophotometer. Results Arsenic concentrations in hair and nails were positively correlated with the arsenic levels in drinking water. Significant decreases in PChE activity were observed with increasing concentrations of arsenic in water, hair and nails. The average levels of PChE activity in low, medium and high arsenic exposure groups were also significantly different between each group. Lower levels of PChE activity were also observed in the > 50 ?g/L group compared to the ?50 ?g/L group. Moreover, PChE activity was significantly decreased in the skin (+) symptoms group compared to those without (-). Conclusions We found a significant inverse relationship between arsenic exposure and PChE activity in a human population in Bangladesh. This research demonstrates a novel exposure-response relationship between arsenic and PChE activity which may explain one of the biological mechanisms through which arsenic exerts its neuro-and hepatotoxicity in humans. PMID:20618979

2010-01-01

370

Potential for Inhalation Exposure to Engineered Nanoparticles from Nanotechnology-Based Cosmetic Powders  

PubMed Central

Background: The market of nanotechnology-based consumer products is rapidly expanding, and the lack of scientific evidence describing the accompanying exposure and health risks stalls the discussion regarding its guidance and regulation. Objectives: We investigated the potential for human contact and inhalation exposure to nanomaterials when using nanotechnology-based cosmetic powders and compare them with analogous products not marketed as nanotechnology based. Methods: We characterized the products using transmission electron microscopy (TEM) and laser diffraction spectroscopy and found nanoparticles in five of six tested products. TEM photomicrographs showed highly agglomerated states of nanoparticles in the products. We realistically simulated the use of cosmetic powders by applying them to the face of a human mannequin head while simultaneously sampling the released airborne particles through the ports installed in the mannequin’s nostrils. Results: We found that a user would be exposed to nanomaterial predominantly through nanoparticle-containing agglomerates larger than the 1–100-nm aerosol fraction. Conclusions: Predominant deposition of nanomaterial(s) will occur in the tracheobronchial and head airways—not in the alveolar region as would be expected based on the size of primary nanoparticles. This could potentially lead to different health effects than expected based on the current understanding of nanoparticle behavior and toxicology studies for the alveolar region. PMID:22394622

Nazarenko, Yevgen; Zhen, Huajun; Han, Taewon; Lioy, Paul J.

2012-01-01

371

Community-Based Participatory Research and Policy Advocacy to Reduce Diesel Exposure in West Oakland, California  

PubMed Central

We conducted a multimethod case study analysis of a community-based participatory research partnership in West Oakland, California, and its efforts to study and address the neighborhood's disproportionate exposure to diesel air pollution. We employed 10 interviews with partners and policymakers, participant observation, and a review of documents. Results of the partnership's truck count and truck idling studies suggested substantial exposure to diesel pollution and were used by the partners and their allies to make the case for a truck route ordinance. Despite weak enforcement, the partnership's increased political visibility helped change the policy environment, with the community partner now heavily engaged in environmental decision-making on the local and regional levels. Finally, we discussed implications for research, policy, and practice. PMID:21551381

Gonzalez, Priscilla A.; Garcia, Analilia P.; Gordon, Margaret; Garzón, Catalina; Palaniappan, Meena; Prakash, Swati; Beveridge, Brian

2011-01-01

372

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

PubMed Central

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

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

2009-01-01

373

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

PubMed

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

Warth, Benedikt; Sulyok, Michael; Krska, Rudolf

2013-07-01

374

Dietary cadmium exposure and prostate cancer incidence: a population-based prospective cohort study  

PubMed Central

Background: Experimental data convincingly propose the toxic metal cadmium as a prostate carcinogen. Cadmium is widely dispersed into the environment and, consequently, food is contaminated. Methods: A population-based cohort of 41?089 Swedish men aged 45–79 years was followed prospectively from 1998 through 2009 to assess the association between food frequency questionnaire-based estimates of dietary cadmium exposure (at baseline, 1998) and incidence of prostate cancer (3085 cases, of which 894 were localised and 794 advanced) and through 2008 for prostate cancer mortality (326 fatal cases). Results: Mean dietary cadmium exposure was 19??g per day±s.d. 3.7. Multivariable-adjusted dietary cadmium exposure was positively associated with overall prostate cancer, comparing extreme tertiles; rate ratio (RR) 1.13 (95% confidence interval (CI): 1.03–1.24). For subtypes of prostate cancer, the RR was 1.29 (95% CI: 1.08–1.53) for localised, 1.05 (95% CI: 0.87–1.25) for advanced, and 1.14 (95% CI: 0.86–1.51) for fatal cases. No statistically significant difference was observed in the multivariable-adjusted risk estimates between tumour subtypes (Pheterogeneity=0.27). For localised prostate cancer, RR was 1.55 (1.16–2.08) among men with a small waist circumference and RR 1.45 (1.15, 1.83) among ever smokers. Conclusion: Our findings provide support that dietary cadmium exposure may have a role in prostate cancer development. PMID:22850555

Julin, B; Wolk, A; Johansson, J-E; Andersson, S-O; Andrén, O; Åkesson, A

2012-01-01

375

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

PubMed Central

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

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

2014-01-01

376

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

NASA Astrophysics Data System (ADS)

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.

Ross, Danielle Kristina

377

Relationships between ozone exposure and yield loss in European wheat and potato—a comparison of concentration- and flux-based exposure indices  

NASA Astrophysics Data System (ADS)

Data from open-top chamber experiments with field grown crops, performed in Sweden, Finland, Belgium, Italy and Germany, were combined to derive relationships between yield and ozone exposure for wheat ( Triticum aestivum L.) and potato ( Solanum tuberosum L.). Three different exposure indices were compared: AOT40 (accumulated exposure over a threshold ozone concentration of 40 nmol mol -1), CUO t (cumulative stomatal uptake of ozone, using a constant ozone uptake rate threshold of t nmol m -2 s -1) and mAOT c0 (conductance modified AOT using a threshold concentration for ozone of c0 nmol mol -1). The latter is essentially a combination of AOT and CUO. Ozone uptake was estimated using a Jarvis-type multiplicative model for stomatal conductance. In terms of correlation between relative yield (RY) and ozone exposure, CUO 5, the CUO index with an ozone uptake rate threshold of 5 nmol m -2 s -1, performed best for both wheat and potato, resulting in r2 values of 0.77 and 0.64, respectively. CUO 5 performed considerably better in terms of the correlation between RY and ozone exposure, than AOT40 for wheat, while mAOT10, the best performing mAOT index in this case, was intermediate in performance for this crop. For potato, the differences between the different ozone exposure indices AOT40, CUO 5 and mAOT20 (the mAOT index performing best for potato) in the correlation between RY and ozone exposure were relatively small. To test the assumption that the non-stomatal deposition of ozone was negligible for the uppermost, sunlit leaves, measurements of ozone uptake in relation to leaf conductance for water vapor of wheat leaves in a cuvette system were used. The non-stomatal deposition of ozone to the leaves turned out to be comparatively small. Based on the non-stomatal conductance ( gns=15 mmol m -2 s -1) estimated for the wheat leaves in the cuvette system, it was concluded that the consequence of omitting the non-stomatal conductance is small. In conclusion the study indicated that the ozone uptake based approach showed a high degree of fitting along a north-south European transect of pedoclimatic conditions, and represents a better and more relevant approach to the quantification of ozone effects on crops growth than the use of ozone exposure indices purely based on ozone concentrations.

Pleijel, H.; Danielsson, H.; Ojanperä, K.; Temmerman, L. De; Högy, P.; Badiani, M.; Karlsson, P. E.

378

EEG, physiology, and task-related mood fail to resolve across 31 days of smoking abstinence: relations to depressive traits, nicotine exposure, and dependence.  

PubMed

Changes in task-related mood and physiology associated with 31 days of smoking abstinence were assessed in smokers, 34 of whom were randomly assigned to a quit group and 22 to a continuing-to-smoke control group. A large financial incentive for smoking abstinence resulted in very low participant attrition. Individuals were tested during prequit baselines and at 3, 10, 17, and 31 days of abstinence. Abstinence was associated with decreases in heart rate and serum cortisol, a slowing of electroencephalogram (EEG) activity, and task-dependent and trait-depression-dependent hemispheric EEG asymmetries. Differences between the quit group and the smoking group showed no tendency to resolve across the 31 days of abstinence. Trait depression and neuroticism correlated with increases in left-relative-to-right frontal EEG slow-wave (low alpha) activity at both 3 and 31 days of abstinence. In contrast, prequit nicotine intake and Fagerström Tolerance scores correlated with alpha asymmetry and with greater EEG slowing only at Day 3. Thus, the effects of smoking abstinence appear to last for at least several months. PMID:10609977

Gilbert, D G; McClernon, F J; Rabinovich, N E; Dibb, W D; Plath, L C; Hiyane, S; Jensen, R A; Meliska, C J; Estes, S L; Gehlbach, B A

1999-11-01

379

Preliminary development and evaluation of an appearance-based dissonance induction intervention for reducing UV exposure.  

PubMed

The current study examined the feasibility of an appearance-based dissonance induction approach for the modification of tanning and sunscreen use behaviors. Undergraduate female students were randomized to: a healthy lifestyle condition, an appearance-based dissonance condition, or an appearance-based psychoeducation condition. Reports of tanning and sunscreen use were collected immediately before and 1 month following intervention (N=225). Relative to the healthy lifestyle condition, participants in the dissonance condition reported a significant reduction in daily hours spent tanning. Additionally, sunscreen use on the body decreased significantly for the healthy lifestyle group, but did not change for the dissonance group. The psychoeducation condition did not differ from the healthy lifestyle condition on any measure. These findings should encourage additional research into the use of dissonance induction as an appearance-based strategy for promoting reductions in UV exposure. PMID:25462883

Chait, Sari R; Thompson, J Kevin; Jacobsen, Paul B

2015-01-01

380

Increase in physical activities in kindergarten children with cerebral palsy by employing MaKey-MaKey-based task systems.  

PubMed

In this study, we employed Flash- and Scratch-based multimedia by using a MaKey-MaKey-based task system to increase the motivation level of children with cerebral palsy to perform physical activities. MaKey MaKey is a circuit board that converts physical touch to a digital signal, which is interpreted by a computer as a keyboard message. In this study, we used conductive materials to control this interaction. This study followed single-case design using ABAB models in which A indicated the baseline and B indicated the intervention. The experiment period comprised 1 month and a half. The experimental results demonstrated that in the case of two kindergarten children with cerebral palsy, their scores were considerably increased during the intervention phrases. The developmental applications of the results are also discussed. PMID:24864049

Lin, Chien-Yu; Chang, Yu-Ming

2014-09-01

381

Saccades to future ball location reveal memory-based prediction in a virtual-reality interception task  

PubMed Central

Despite general agreement that prediction is a central aspect of perception, there is relatively little evidence concerning the basis on which visual predictions are made. Although both saccadic and pursuit eye-movements reveal knowledge of the future position of a moving visual target, in many of these studies targets move along simple trajectories through a fronto-parallel plane. Here, using a naturalistic and racquet-based interception task in a virtual environment, we demonstrate that subjects make accurate predictions of visual target motion, even when targets follow trajectories determined by the complex dynamics of physical interactions and the head and body are unrestrained. Furthermore, we found that, following a change in ball elasticity, subjects were able to accurately adjust their prebounce predictions of the ball's post-bounce trajectory. This suggests that prediction is guided by experience-based models of how information in the visual image will change over time. PMID:23325347

Diaz, Gabriel; Cooper, Joseph; Rothkopf, Constantin; Hayhoe, Mary

2013-01-01

382

Results of a clinician-led evidence-based task force initiative relating to pressure ulcer risk assessment and prevention.  

PubMed

Integration of research findings into clinical practice is essential for achieving cost-effective, quality patient outcomes. Data confirm that nursing care in most settings is "empiric" and is based largely on untested assumptions, as opposed to being evidence-based. Process improvement efforts must engage clinicians in initiatives that promote the integration of research into clinical practice and acceptance of shared professional accountability for sustaining needed change. A clinician-led task force was assembled to identify and apply current evidence to clinical practice in the areas of risk assessment and prevention of hospital-acquired pressure ulcers in the inpatient setting. Data collected prior to and following our process improvement project demonstrated significant improvement in patient outcomes. PMID:20736858

Young, Judith; Ernsting, Mary; Kehoe, Amira; Holmes, Kathleen

2010-01-01

383

Exposure of juvenile green frogs (Lithobates clamitans) in littoral enclosures to a glyphosate-based herbicide.  

PubMed

The majority of studies on the toxicity of glyphosate-based herbicides to amphibians have focused on larval life stages exposed in aqueous media. However, adult and juvenile amphibians may also be exposed directly or indirectly to herbicides. The potential for such exposures is of particular interest in the littoral zone surrounding wetlands as this is preferred habitat for many amphibian species. Moreover, it may be argued that potential herbicide effects on juvenile or adult amphibians could have comparatively greater influence on overall recruitment, reproductive potential and thus stability of local populations than effects on larvae. In this experiment, juvenile green frogs (Lithobates clamitans) were exposed to two concentrations (2.16 and 4.27 kg a.e./ha) of a glyphosate-based herbicide formulation (VisionMax®), which were based on typical application scenarios in Canadian forestry. The experimental design employed frogs inhabiting in situ enclosures established at the edge of small naturalized wetlands that were split in half using an impermeable plastic barrier. When analyzed using nominal target application rates, exposure to the glyphosate-based herbicide had no significant effect on survival, body condition, liver somatic index or the observed rate of Batrachochytrium dendrobatidis infection. However, there were marginal trends in both ANOVA analysis and post-hoc regressions regarding B. dendrobatidis infection rates and liver somatic index in relation to measured exposure estimates. Results from this study highlight the importance of field research and the need to include multiple endpoints when examining potential effects of a contaminant on non-target organisms. PMID:21536331

Edge, Christopher B; Gahl, Megan K; Pauli, Bruce D; Thompson, Dean G; Houlahan, Jeff E

2011-07-01

384

Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling  

SciTech Connect

In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information—inside hotspots or in search of them—based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km{sup 2}. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2 dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. -- Highlights: • We present an iterative measurement and modeling method for outdoor RF-EMF exposure. • Hotspots are rapidly identified, and accurately characterized. • An accurate graphical representation, or heat map, is created, using kriging. • Random validation shows good correlation (0.7) and low relative errors (2 dB)

Aerts, Sam, E-mail: sam.aerts@intec.ugent.be; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

2013-10-15

385

A Systematic Understanding of Successful Web Searches in Information-Based Tasks  

ERIC Educational Resources Information Center

The purpose of this study is to research how Chinese university students solve information-based problems. With the Search Performance Index as the measure of search success, participants were divided into high, medium and low-performing groups. Based on their web search logs, these three groups were compared along five dimensions of the search…

Zhou, Mingming

2013-01-01

386

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

ERIC Educational Resources Information Center

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

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

2009-01-01

387

Assessment of human deoxynivalenol exposure using an LC-MS/MS based biomarker method.  

PubMed

The Fusarium toxin deoxynivalenol (DON) is one of the most abundant mycotoxins worldwide and poses many adverse health effects to human and animals. Consequently, regulatory limits and a provisional maximum tolerable daily intake (PMTDI) for this important type B-trichothecene were assigned. We conducted a pilot survey to investigate the level of DON exposure in Austrian adults by measurements of DON and its glucuronide conjugates (DON-GlcA's), as biomarkers of exposure, in first morning urine. The average concentration of total DON (free DON+DON-GlcA's) was estimated to be 20.4±2.4 ?g L?¹ (max. 63 ?g L?¹). Surprisingly, we found that one third of the volunteers (n=27) exceeded the established PMTDI when consuming regular diet. DON-GlcA's were directly quantified by LC-MS/MS and the results were compared with indirect quantification after enzymatic hydrolysis and confirmed the suitability of the direct method. Moreover, we investigated the in vivo metabolism of DON in humans and were able to determine two closely eluting DON-GlcA's in naturally contaminated urine samples for the first time. In contrast to previous findings we have tentatively identified DON-15-glucuronide as a major DON metabolite in human urine based on the analysis of these samples. About 75% of total glucuronides were derived from this metabolite while DON-3-glucuronide accounted for approximately 25%. The reported new findings clearly demonstrate the great potential of suitable biomarkers to critically assess exposure of humans and animals to DON. PMID:22429874

Warth, Benedikt; Sulyok, Michael; Fruhmann, Philipp; Berthiller, Franz; Schuhmacher, Rainer; Hametner, Christian; Adam, Gerhard; Fröhlich, Johannes; Krska, Rudolf

2012-05-20

388

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...

389

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...

390

Adding sirolimus to tacrolimus-based immunosuppression in pediatric renal transplant recipients reduces tacrolimus exposure.  

PubMed

In adult renal recipients, coadministration of tacrolimus (TAC) and sirolimus (SIR) results in reduced exposure to TAC at SIR doses of 2 mg/day. Eight pediatric renal recipients (median age at transplant 2.0 years, range: 1.2-12.9 years) were converted to TAC- and SIR-based immunosuppression as a rescue therapy. All patients had biopsy-proven chronic allograft nephropathy. TAC levels were measured using a commercially available EMIT assay and SIR levels with a newly developed assay based on the LC-MS MS technology. SIR was started at 0.13+/-0.05 mg/kg/day (3.51+/-1.26 mg/m2/day) in two divided doses. TAC was given at 0.14+/-0.09 mg/kg/day, resulting in a trough level of 6.3+/-2.5 ng/mL. After the addition of SIR, the median dose required to keep TAC blood trough concentrations within the target range increased by 71.2% (range: 21.9-245.4%), dose-normalized TAC exposure (AUC) decreased to 67.1% and the dose-normalized C(max), a surrogate for absorption rate, to 53.8% (both geometric means) while terminal half-life (t1/2), a pharmacokinetic parameter characterizing systemic elimination, remained unchanged (p<0.93). Adding SIR to TAC-based immunosuppression in young pediatric renal transplant recipients results in a significant decrease of TAC exposure. TAC trough levels should be monitored frequently. PMID:15996252

Filler, Guido; Womiloju, Taiwo; Feber, Janusz; Lepage, Nathalie; Christians, Uwe

2005-08-01

391

Touchscreen-Based Cognitive Tasks Reveal Age-Related Impairment in a Primate Aging Model, the Grey Mouse Lemur (Microcebus murinus)  

PubMed Central

Mouse lemurs are suggested to represent promising novel non-human primate models for aging research. However, standardized and cross-taxa cognitive testing methods are still lacking. Touchscreen-based testing procedures have proven high stimulus control and reliability in humans and rodents. The aim of this study was to adapt these procedures to mouse lemurs, thereby exploring the effect of age. We measured appetitive learning and cognitive flexibility of two age groups by applying pairwise visual discrimination (PD) and reversal learning (PDR) tasks. On average, mouse lemurs needed 24 days of training before starting with the PD task. Individual performances in PD and PDR tasks correlate significantly, suggesting that individual learning performance is unrelated to the respective task. Compared to the young, aged mouse lemurs showed impairments in both PD and PDR tasks. They needed significantly more trials to reach the task criteria. A much higher inter-individual variation in old than in young adults was revealed. Furthermore, in the PDR task, we found a significantly higher perseverance in aged compared to young adults, indicating an age-related deficit in cognitive flexibility. This study presents the first touchscreen-based data on the cognitive skills and age-related dysfunction in mouse lemurs and provides a unique basis to study mechanisms of inter-individual variation. It furthermore opens exciting perspectives for comparative approaches in aging, personality, and evolutionary research. PMID:25299046

2014-01-01

392

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

PubMed Central

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

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

2013-01-01

393

Reward-based Decision Making and Electrodermal Responding by Young Children with Autism Spectrum Disorders During a Gambling Task  

PubMed Central

In this study, we explore reward-based decision making and electrodermal responding (EDR) among children with autism spectrum disorder (ASD) during a children’s gambling task. In addition, we examine whether individual behavioral and EDR responses predict social communication, repetitive symptoms, parent reports of executive function, and behavioral challenges. The ability to form advantageous strategies for long-term gain is of interest for children with ASDs, who exhibit both difficulty with executive function and atypical responses to reward. Twenty-one children ages 6–7 years with ASD and no intellectual disability and 21 age- and IQ-matched typically developing children participated. Both groups exhibited a similar pattern of gambling selections, but children with ASD showed less knowledge of the reward contingencies of the decks after playing. In addition, although EDR was similar between groups in anticipation of selections, children with ASD exhibited greater EDR during feedback about rewards as the task progressed. Children with ASD who exhibited the greatest increases in EDR were more likely to exhibit repetitive symptoms, particularly rituals and the need for sameness, as well as internalizing behaviors and reduced executive function in other settings. PMID:23893954

Faja, Susan; Murias, Michael; Beauchaine, Theodore P.; Dawson, Geraldine

2014-01-01

394

A modular design kit for task-adaptable low-cost robots based on BaPaMan design  

NASA Astrophysics Data System (ADS)

This paper discusses the redesign of a binary parallel manipulator named BaPaMan (Binary Actuated Parallel Manipulator). The aim of this work is the improvement of the structures stiffness of BaPaMan. Additionally this paper shows the implementation of a construction kit which allows task-adaptation of low-cost robots based on the BaPaMan structure. BaPaMan is a three degree of freedom (DOF) spatial parallel robot which comprises flexure hinges and Shape Memory Alloy (SMA) actuators to achieve a low-cost design, well suited for easy operation applications. Measurements have shown that this comes at the cost of poor structural stiffness and end effector accuracy. To counter these issues BaPaMan2 and BaPaMan3 have been developed and are elaborated within this work. During the design phase, an empirical FEA is used to improve the flexure hinge performance, which analyses relations between several design parameters and the stiffness of the entire system. Finally, task-adaptation is achieved by using a design methodology and a parametric CAD model for BaPaMan. Besides the paper introduces first applications of the BaPaMan structure and shows future work.

Borchert, G.; Löchte, C.; Carbone, G.; Raatz, A.

2013-03-01

395

Functional near-infrared spectroscopy-based correlates of prefrontal cortical dynamics during a cognitive-motor executive adaptation task  

PubMed Central

This study investigated changes in brain hemodynamics, as measured by functional near infrared spectroscopy, during performance of a cognitive-motor adaptation task. The adaptation task involved the learning of a novel visuomotor transformation (a 60° counterclockwise screen-cursor rotation), which required inhibition of a prepotent visuomotor response. A control group experienced a familiar transformation and thus, did not face any executive challenge. Analysis of the experimental group hemodynamic responses revealed that the performance enhancement was associated with a monotonic reduction in the oxygenation level in the prefrontal cortex. This finding confirms and extends functional magnetic resonance imaging and electroencephalography studies of visuomotor adaptation and learning. The changes in prefrontal brain activation suggest an initial recruitment of frontal executive functioning to inhibit prepotent visuomotor mappings followed by a progressive de-recruitment of the same prefrontal regions. The prefrontal hemodynamic changes observed in the experimental group translated into enhanced motor performance revealed by a reduction in movement time, movement extent, root mean square error and the directional error. These kinematic adaptations are consistent with the acquisition of an internal model of the novel visuomotor transformation. No comparable change was observed in the control group for either the hemodynamics or for the kinematics. This study (1) extends our understanding of the frontal executive processes from the cognitive to the cognitive-motor domain and (2) suggests that optical brain imaging can be employed to provide hemodynamic based-biomarkers to assess and monitor the level of adaptive cognitive-motor performance. PMID:23847489

Gentili, Rodolphe J.; Shewokis, Patricia A.; Ayaz, Hasan; Contreras-Vidal, José L.

2013-01-01

396

The Effectiveness of a Task-Based Instruction Program in Developing the English Language Speaking Skills of Secondary Stage Students  

ERIC Educational Resources Information Center

Communicative tasks are defined as activities in which meaning is primary, there is a goal which needs to be worked toward, there is a real world relationship and the interaction among students is the means for achieving the task outcome. However, it was assumed that adopting communicative tasks alone is not adequate as it leads the learner to…

Torky, Shaimaa Abd EL Fattah

2006-01-01

397

The Web as a Baseline: Evaluating the Performance of Unsupervised Web-based Models for a Range of NLP Tasks  

Microsoft Academic Search

Previous work demonstrated that web counts can be used to approximate bigram frequen- cies, and thus should be useful for a wide va- riety of NLP tasks. So far, only two gener- ation tasks (candidate selection for machine translation and confusion-set disambiguation) have been tested using web-scale data sets. The present paper investigates if these results gener- alize to tasks

Mirella Lapata; Frank Keller

2004-01-01

398

Shotgun metabolomic approach based on mass spectrometry for hepatic mitochondria of mice under arsenic exposure.  

PubMed

Mass spectrometry (MS)-based toxicometabolomics requires analytical approaches for obtaining unbiased metabolic profiles. The present work explores the general application of direct infusion MS using a high mass resolution analyzer (a hybrid systems triple quadrupole-time-of-flight) and a complementary gas chromatography-MS analysis to mitochondria extracts from mouse hepatic cells, emphasizing on mitochondria isolation from hepatic cells with a commercial kit, sample treatment after cell lysis, comprehensive metabolomic analysis and pattern recognition from metabolic profiles. Finally, the metabolomic platform was successfully checked on a case-study based on the exposure experiment of mice Mus musculus to inorganic arsenic during 12 days. Endogenous metabolites alterations were recognized by partial least squares-discriminant analysis. Subsequently, metabolites were identified by combining MS/MS analysis and metabolomics databases. This work reports for the first time the effects of As-exposure on hepatic mitochondria metabolic pathways based on MS, and reveals disturbances in Krebs cycle, ?-oxidation pathway, amino acids degradation and perturbations in creatine levels. This non-target analysis provides extensive metabolic information from mitochondrial organelle, which could be applied to toxicology, pharmacology and clinical studies. PMID:25753946

García-Sevillano, M A; García-Barrera, T; Navarro, F; Montero-Lobato, Z; Gómez-Ariza, J L

2015-04-01

399

Deprotection blue in extreme ultraviolet photoresists: influence of base loading and post-exposure bake temperture  

SciTech Connect

The deprotection blur of Rohm and Haas XP 5435, XP 5271, and XP5496 extreme ultraviolet photoresists has been determined as their base weight percent is varied. They have also determined the deprotection blur of TOK EUVR P1123 photoresist as the post-exposure bake temperature is varied from 80 C to 120 C. In Rohm and Haas XP 5435 and XP5271 resists 7x and 3x (respective) increases in base weight percent reduce the size of successfully patterned 1:1 line-space features by 16 nm and 8 nm with corresponding reductions in deprotection blur of 7 nm and 4 nm. In XP 5496 a 7x increase in base weight percent reduces the size of successfully patterned 1:1 line-space features from 48 nm to 38 nm without changing deprotection blur. In TOK EUVR P1123 resist, a reduction in post-exposure bake temperature from 100 C to 80 C reduces deprotection blur from 21 nm to 10 nm and reduces patterned LER from 4.8 nm to 4.1 nm.

Anderson, Christopher N.; Naulleau, Patrick P.

2008-06-02

400

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

NASA Technical Reports Server (NTRS)

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.

Gray, H. R.

1975-01-01

401

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

NASA Technical Reports Server (NTRS)

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.

Looney, Alan

1991-01-01

402

Confronting Prospective Teachers' Ideas of Evolution and Scientific Inquiry Using Technology and Inquiry-Based Tasks  

ERIC Educational Resources Information Center

This study addresses the need for research in three areas: (1) teachers' understandings of scientific inquiry; (2) conceptual understandings of evolutionary processes; and (3) technology-enhanced instruction using an inquiry approach. The purpose of this study was to determine in what ways "The Galapagos Finches" software-based materials created a…

Crawford, Barbara A.; Zembal-Saul, Carla; Munford, Danusa; Friedrichsen, Patricia

2005-01-01

403

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

ERIC Educational Resources Information Center

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…

Bell, Benjamin

404

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

405

From First Life to Second Life: Evaluating Task-Based Language Learning in a New Environment  

ERIC Educational Resources Information Center

With its growing number of users, Second Life as one of the avatar-based 3D virtual worlds has received attention from educators and researchers in various fields to explore its pedagogical benefits. Given the increasing implementation of technologies broadly in much instruction, this study investigated how ESL students negotiated meanings in…

Jee, Min Jung

2014-01-01

406

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

ERIC Educational Resources Information Center

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.…

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

2012-01-01

407

Engineering Challenges of Deploying Crowd-based Data Collection Tasks to End-User Controlled Smartphones  

E-print Network

Smartphones Hamilton Turner Virginia Tech Blacksburg, VA, USA hamiltont@vt.edu Jules White Virginia Tech The emerging hardware resources available in smartphones has increased the potential for effective crowdsourced crowdsourced data collection. However, given the recent emergence of smartphone-based data collection systems

Gray, Jeffrey G.

408

Preparing Students for Education, Work, and Community: Activity Theory in Task-Based Curriculum Design  

ERIC Educational Resources Information Center

This case study describes how sociocultural and activity theory were applied in the design of a publicly funded, Canadian Language Benchmark (CLB)-based English as a Second Language (ESL) credential program and curriculum for immigrant and international students in postsecondary institutions in British Columbia, Canada. The ESL Pathways Project…

Campbell, Chris; MacPherson, Seonaigh; Sawkins, Tanis

2014-01-01

409

Static Scheduling of ObjectBased Realtime Tasks with Probabilistic Conditional Branches in  

E-print Network

of present real­time systems. Such systems are life­critical and the outcome would be catastrophic, and distributed. The complexity in the development of software for such systems can be managed by using object­based design and methodology [1]. Even though the reusable software components contained in the object

Manimaran, Govindarasu

410

Flocking task research for multiple mobile robots based on game theory  

Microsoft Academic Search

It established multi-objective optimal mathematic model and did research on solving methods based on game theory. First, n robots specified n players. Second, it decomposed the design variables set and took the design variables set of paths which belonged to each robot as strategy space of the corresponding players. Third, it established mapping relationships between payoff functions and objective functions

Yuwan Cen; Ye Ye; Nenggang Xie; Jiahan Bao; Chongzhi Song

2008-01-01

411

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

Microsoft Academic Search

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

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

2004-01-01

412

Task breakdown  

NASA Technical Reports Server (NTRS)

The topics concerning the Center for Space Construction (CSC) space construction breakdown structure are presented in viewgraph form. It is concluded that four components describe a task -- effecting, information gathering, analysis, and regulation; uncertainties effect the relative amount of information gathering and analysis that occurs; and that task timing requirements drive the 'location in time' of cognition.

Pavlich, Jane

1990-01-01

413

Task Description Language  

NASA Technical Reports Server (NTRS)

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.

Simmons, Reid; Apfelbaum, David

2005-01-01

414

Pollutant Exposures from Natural Gas Cooking Burners: A Simulation-Based Assessment for Southern California  

PubMed Central

Background: Residential natural gas cooking burners (NGCBs) can emit substantial quantities of pollutants, and they are typically used without venting range hoods. Objective: We quantified pollutant concentrations and occupant exposures resulting from NGCB use in California homes. Methods: A mass-balance model was applied to estimate time-dependent pollutant concentrations throughout homes in Southern California and the exposure concentrations experienced by individual occupants. We estimated nitrogen dioxide (NO2), carbon monoxide (CO), and formaldehyde (HCHO) concentrations for 1 week each in summer and winter for a representative sample of Southern California homes. The model simulated pollutant emissions from NGCBs as well as NO2 and CO entry from outdoors, dilution throughout the home, and removal by ventilation and deposition. Residence characteristics and outdoor concentrations of NO2 and CO were obtained from available databases. We inferred ventilation rates, occupancy patterns, and burner use from household characteristics. We also explored proximity to the burner(s) and the benefits of using venting range hoods. Replicate model executions using independently generated sets of stochastic variable values yielded estimated pollutant concentration distributions with geometric means varying by < 10%. Results: The simulation model estimated that—in homes using NGCBs without coincident use of venting range hoods—62%, 9%, and 53% of occupants are routinely exposed to NO2, CO, and HCHO levels that exceed acute health-based standards and guidelines. NGCB use increased the sample median of the highest simulated 1-hr indoor concentrations by 100, 3,000, and 20 ppb for NO2, CO, and HCHO, respectively. Conclusions: Reducing pollutant exposures from NGCBs should be a public health priority. Simulation results suggest that regular use of even moderately effective venting range hoods would dramatically reduce the percentage of homes in which concentrations exceed health-based standards. Citation: Logue JM, Klepeis NE, Lobscheid AB, Singer BC. 2014. Pollutant exposures from natural gas cooking burners: a simulation-based assessment for Southern California. Environ Health Perspect 122:43–50;?http://dx.doi.org/10.1289/ehp.1306673 PMID:24192135

Klepeis, Neil E.; Lobscheid, Agnes B.; Singer, Brett C.

2013-01-01

415

Pollutant Exposures from Natural Gas Cooking Burners: A Simulation-Based Assessment for Southern California  

SciTech Connect

Residential natural gas cooking burners (NGCBs) can emit substantial quantities of pollutants and they are typically used without venting. The objective of this study is to quantify pollutant concentrations and occupant exposures resulting from NGCB use in California homes. A mass balance model was applied to estimate time-dependent pollutant concentrations throughout homes and the "exposure concentrations" experienced by individual occupants. The model was applied to estimate nitrogen dioxide (NO{sub 2}), carbon monoxide (CO), and formaldehyde (HCHO) concentrations for one week each in summer and winter for a representative sample of Southern California homes. The model simulated pollutant emissions from NGCBs, NO{sub 2} and CO entry from outdoors, dilution throughout the home, and removal by ventilation and deposition. Residence characteristics and outdoor concentrations of CO and NO{sub 2} were obtained from available databases. Ventilation rates, occupancy patterns, and burner use were inferred from household characteristics. Proximity to the burner(s) and the benefits of using venting range hoods were also explored. Replicate model executions using independently generated sets of stochastic variable values yielded estimated pollutant concentration distributions with geometric means varying less than 10%. The simulation model estimates that in homes using NGCBs without coincident use of venting range hoods, 62%, 9%, and 53% of occupants are routinely exposed to NO{sub 2}, CO, and HCHO levels that exceed acute health-based standards and guidelines. NGCB use increased the sample median of the highest simulated 1-hr indoor concentrations by 100, 3000, and 20 ppb for NO{sub 2}, CO, and HCHO, respectively. Reducing pollutant exposures from NGCBs should be a public health priority. Simulation results suggest that regular use of even moderately effective venting range hoods would dramatically reduce the percentage of homes in which concentrations exceed health-based standards.

Logue, Jennifer M.; Klepeis, Neil E.; Lobscheid, Agnes B.; Singer, Brett C.

2014-06-01

416

Mileage Based User Fee Policy Task Force Lee Munnich, Senior Fellow, Humphrey School of  

E-print Network

Annually (taxes per year) Light Duty Truck (20 mpg) Passenger Car (30 mpg) Hybrid (40 mpg) Electric Vehicle (delivery truck) 2.8 4.6 20 (light duty truck) 1.4 2.3 30 (passenger car) 0.9 1.5 40 (hybrid) 0.7 1.1 50 (hybrid) 0.6 0.9 8 #12;Mileage-Based User Fee ·Drivers pay for road use on a per-mile rather than per

Minnesota, University of

417

Supported and liquid phase task specific ionic liquids for base catalysed Knoevenagel reactions  

Microsoft Academic Search

A series of Hünig's base tethered ammonium ionic liquids have been used to catalyse the Knoevenagel condensation of aldehydes\\/ketones with malononitrile and ethyl cyanoacetate. The reactions were performed under homogeneous and under biphasic, liquid–liquid and liquid–silica supported ionic liquid, conditions with the biphasic systems employing cyclohexene as the second phase. By increasing the distance between the ammonium head group and

C. Paun; J. Barklie; P. Goodrich; H. Q. N. Gunaratne; A. McKeown; V. I. Pârvulescu; C. Hardacre

2007-01-01

418

Real-time task reconfiguration support applied to an UAV-based surveillance system  

Microsoft Academic Search

Modern surveillance systems, such as those based on the use of unmanned aerial vehicles, required powerful high-performance platforms to deal with many different algorithms that make use of massive calculations. At the same time, low-cost and high-performance specific hardware (e.g., GPU, PPU) are rising and the CPUs turned to multiple cores, characterizing together an interesting and powerful heterogeneous execution platform.

Alécio Pedro Delazari Binotto; Edison Pignaton de Freitas; Carlos Eduardo Pereira; André Stork; Tony Larsson

2008-01-01

419

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

PubMed Central

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

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

2004-01-01

420

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

PubMed Central

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

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

421

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

SciTech Connect

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.

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

1985-01-01

422

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

PubMed

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

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

2006-01-01

423

New exposure-based metric approach for evaluating O(3) risk to North American aspen forests.  

PubMed

The United States and Canada currently use exposure-based metrics to protect vegetation from O(3). Using 5 years (1999-2003) of co-measured O(3), meteorology and growth response, we have developed exposure-based regression models that predict Populus tremuloides growth change within the North American ambient air quality context. The models comprised growing season fourth-highest daily maximum 8-h average O(3) concentration, growing degree days, and wind speed. They had high statistical significance, high goodness of fit, include 95% confidence intervals for tree growth change, and are simple to use. Averaged across a wide range of clonal sensitivity, historical 2001-2003 growth change over most of the 26 Mha P. tremuloides distribution was estimated to have ranged from no impact (0%) to strong negative impacts (-31%). With four aspen clones responding negatively (one responded positively) to O(3), the growing season fourth-highest daily maximum 8-h average O(3) concentration performed much better than growing season SUM06, AOT40 or maximum 1h average O(3) concentration metrics as a single indicator of aspen stem cross-sectional area growth. PMID:17140714

Percy, K E; Nosal, M; Heilman, W; Dann, T; Sober, J; Legge, A H; Karnosky, D F

2007-06-01

424

Butoxyethoxyacetic acid, a biomarker of exposure to water-based cleaning agents.  

PubMed

The aim of the study was to investigate the suitability of butoxyethoxyacetic acid (BEAA) as a biomarker of exposure to water-based cleaning agents containing diethylene glycol mono butyl ether (DEGBE). The study was performed in two printing plants where water-based products containing 10-15% DEGBE were used for rubber and blanket washes. Thirty nine newspaper pressroom workers (exposed) and 19 employees of newspaper despatch departments (controls) were investigated. By questionnaire, the workers were asked about the use of personal protective measures. BEAA was determined in post-shift urine using GC-MS. The BEAA concentration in the urine of exposed workers ranged up to 75.1 mg/l (median 6.3 mg/l), whereas in urine samples of the controls the BEAA level was below or around the determination limit of 0.5 mg/l. A protective effect on DEGBE uptake was observed with the use of protective gloves. This observation implies that dermal penetration of DEGBE may be important in exposure monitoring. PMID:12191891

Göen, Thomas; Korinth, Gintautas; Drexler, Hans

2002-08-01

425

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

PubMed Central

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

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

2014-01-01

426

Comparison of motor-based versus visual sensory representations in object recognition tasks  

E-print Network

. This theory is demonstrated by a Java-based program. The program does its pattern matching in quite a straight forward way using what the paper calls the sensory motor scheme (SMS). An SMS is just a sequence of notes that the system is internally playing... and determining if it is tuned to the observed environmental stimulus. Initially, the system starts off with a default SMS. If it matches the observed state of the environment, the particular SMS is deemed to be successful. Then more SMSs with similar action...

Misra, Navendu

2005-11-01

427

Lunar lander conceptual design: Lunar base systems study task 2.2  

NASA Technical Reports Server (NTRS)

This study is a first look at the problem of building a lunar lander to support a small lunar surface base. One lander, which can land 25 metric tons, one way, or take a 6 metric ton crew capsule up and down is desired. A series of trade studies are used to narrow the choices and provide some general guidelines. Given a rough baseline, the systems are then reviewed. A conceptual design is then produced. The process was only carried through one iteration. Many more iterations are needed. Assumptions and groundrules are considered.

1988-01-01

428

Comparison of flying qualities derived from in-flight and ground-based simulators for a jet-transport airplane for the approach and landing pilot tasks  

NASA Technical Reports Server (NTRS)

The primary objective was to provide information to the flight controls/flying qualities engineer that will assist him in determining the incremental flying qualities and/or pilot-performance differences that may be expected between results obtained via ground-based simulation (and, in particular, the six-degree-of-freedom Langley Visual/Motion Simulator (VMS)) and flight tests. Pilot opinion and performance parameters derived from a ground-based simulator and an in-flight simulator are compared for a jet-transport airplane having 32 different longitudinal dynamic response characteristics. The primary pilot tasks were the approach and landing tasks with emphasis on the landing-flare task. The results indicate that, in general, flying qualities results obtained from the ground-based simulator may be considered conservative-especially when the pilot task requires tight pilot control as during the landing flare. The one exception to this, according to the present study, was that the pilots were more tolerant of large time delays in the airplane response on the ground-based simulator. The results also indicated that the ground-based simulator (particularly the Langley VMS) is not adequate for assessing pilot/vehicle performance capabilities (i.e., the sink rate performance for the landing-flare task when the pilot has little depth/height perception from the outside scene presentation).

Grantham, William D.

1989-01-01

429

Self-Tuning Laser Speckle Contrast Analysis Based on Multiple Exposure Times with Enhanced Temporal Resolution  

NASA Astrophysics Data System (ADS)

Laser Speckle Contrast Analysis (LASCA) was introduced in 1981. Since then, several enhancements were applied to it. Nowadays, thetechnique can provide relatively high accuracy as well as high temporal and spatial resolution during the examination of ocular or cerebraltissues. However, in the case of skin, the results are highly affected by the intensive scattering on the skin surface, as the scattering onthe non-moving parts of the sample lead to the detrimental decrease of the accuracy. We present a LASCA method based on the use ofmultiple exposure times, combined with the switching-mode control of the light intensity and a special sampling technique to achieve nearto real-time measurement of the skin perfusion. The system based on our method is able to automatically handle the destructive effect ofthe skin surface and re-tune itself according to the changes of the sample, while it provides full-field perfusion maps with high accuracy,without the need of any precalibrations.

Zölei, D.; Smausz, T.; Hopp, B.; Bari, F.

2013-08-01

430

Changes in college students' perceptions of use of web-based resources for academic tasks with Wikipedia projects: a preliminary exploration  

Microsoft Academic Search

Motivated by the need to facilitate Net Generation students' information literacy (IL), or more specifically, to promote student understanding of legitimate, effective use of Web-based resources, this exploratory study investigated how analyzing, writing, posting, and monitoring Wikipedia entries might help students develop critical perspectives related to the legitimacy of Wikipedia and other publicly accessible Web-based resources for academic tasks. Results

Tomoko Traphagan; John Traphagan; Linda Neavel Dickens; Paul Resta

2012-01-01

431

Dermal exposure and urinary 1-hydroxypyrene among asphalt roofing workers  

SciTech Connect

The primary objective of this study was to identify significant determinants of dermal exposure to polycyclic aromatic compounds (PACs) among asphalt roofing workers and use urinary 1-hydroxyprene (1-OHP) measurements to evaluate the effect of dermal exposure on total absorbed dose. The study population included 26 asphalt roofing workers who performed three primary tasks: tearing off old roofs, putting down new roofs, and operating the kettle at ground level. During multiple consecutive work shifts, dermal patch samples were collected from the underside of each worker's wrists and were analyzed for PACs, pyrene, and benzo(a)pyrene (BAP). During the same work week, urine samples were collected at pre-shift, post-shift, and bedtime each day and were analyzed for 1-OHP (205 urine samples). Linear mixed effects models were used to evaluate the dermal measurements for the purpose of identifying important determinants of exposure, and to evaluate urinary 1-OHP measurements for the purpose of identifying important determinants of total absorbed dose. Dermal exposures to PAC, pyrene, and BAP were found to vary significantly by roofing task and by the presence of an old coal tar pitch roof. For each of the three analytes, the adjusted mean dermal exposures associated with tear-off were approximately four times higher than exposures associated with operating the kettle. Exposure to coal tar pitch was associated with a 6-fold increase in PAC exposure, an 8-fold increase in pyrene exposure and a 35-fold increase in BAP exposure. The presence of coal tar pitch was the primary determinant of dermal exposure, particularly for exposure to BAP. However, the task-based differences that were observed while controlling for pitch suggest that exposure to asphalt also contributes to dermal exposures.

McClean, M.D.; Rinehart, R.D.; Sapkota, A.; Cavallari, J.M.; Herrick, R.F. [Boston University School of Public Health, Boston, MA (United States)

2007-07-01

432

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

SciTech Connect

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.

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

433

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

PubMed Central

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

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

434

The double task of preventing malnutrition and overweight: a quasi-experimental community-based trial  

PubMed Central

Background The Maternal-Child Pastoral is a volunteer-based community organization of the Dominican Republic that works with families to improve child survival and development. A program that promotes key practices of maternal and child care through meetings with pregnant women and home visits to promote child growth and development was designed and implemented. This study aims to evaluate the impact of the program on nutritional status indicators of children in the first two years of age. Methods A quasi-experimental design was used, with groups paired according to a socioeconomic index, comparing eight geographical areas of intervention with eight control areas. The intervention was carried out by lay health volunteers. Mothers in the intervention areas received home visits each month and participated in a group activity held biweekly during pregnancy and monthly after birth. The primary outcomes were length and body mass index for age. Statistical analyses were based on linear and logistic regression models. Results 196 children in the intervention group and 263 in the control group were evaluated. The intervention did not show statistically significant effects on length, but point estimates found were in the desired direction: mean difference 0.21 (95%CI ?0.02; 0.44) for length-for-age Z-score and OR 0.50 (95%CI 0.22; 1.10) for stunting. Significant reductions of BMI-for-age Z-score (?0.31, 95%CI ?0.49; -0.12) and of BMI-for-age > 85th percentile (0.43, 95%CI 0.23; 0.77) were observed. The intervention showed positive effects in some indicators of intermediary factors such as growth monitoring, health promotion activities, micronutrient supplementation, exclusive breastfeeding and complementary feeding. Conclusions Despite finding effect measures pointing to effects in the desired direction related to malnutrition, we could only detect a reduction in the risk of overweight attributable to the intervention. The findings related to obesity prevention may be of interest in the context of the nutritional transition. Given the size of this study, the results are encouraging and we believe a larger study is warranted. PMID:23496939

2013-01-01

435

Confronting prospective teachers' ideas of evolution and scientific inquiry using technology and inquiry-based tasks  

NASA Astrophysics Data System (ADS)

This study addresses the need for research in three areas: (1) teachers' understandings of scientific inquiry; (2) conceptual understandings of evolutionary processes; and (3) technology-enhanced instruction using an inquiry approach. The purpose of this study was to determine in what ways The Galapagos Finches software-based materials created a context for learning and teaching about the nature of scientific knowledge and evolutionary concepts. The research used a design experiment in which researchers significantly modified a secondary science methods course. The multiple data sources included: audiotaped conversations of two focus pairs of participants as they interacted with the software; written pre- and posttests on concepts of natural selection of the 21 prospective teachers; written pre- and posttests on views of the nature of science; three e-mail journal questions; and videotaped class discussions. Findings indicate that prospective teachers initially demonstrated alternative understandings of evolutionary concepts; there were uninformed understandings of the nature of scientific inquiry; there was little correlation between understandings and disciplines; and even the prospective teachers with research experience failed to understand the diverse methods used by scientists. Following the module there was evidence of enhanced understandings through metacognition, and the potential for interactive software to provide promising context for enhancing content understandings.

Crawford, Barbara A.; Zembal-Saul, Carla; Munford, Danusa; Friedrichsen, Patricia

2005-08-01

436

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

SciTech Connect

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 t