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1

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

PubMed

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

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

2013-04-01

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

PubMed Central

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

Svendsen, S; Mathiassen, S; Bonde, J

2005-01-01

4

A simultaneous job- and task-based exposure evaluation of petroleum tanker drivers to benzene and total hydrocarbons.  

PubMed

A simultaneous job- and task-based exposure study was conducted for tanker drivers delivering petroleum products from several bulk terminals and an agency to retail outlets. Full-shift (job-based) samples and job component tasks samples were collected simultaneously. The tasks sampled included loading, unloading, and travel. Three hundred sixty-six personal charcoal tube samples were collected. Full-shift visual observations of work practices and real-time monitoring using a data logging hydrocarbon analyzer were also conducted. Multiple measurements per worker were made, which permitted an assessment of sampling variability within and between workers. The highest exposures for drivers occurred during unloading at the agency. The mean benzene exposure for agency drivers was 0.88 ppm for full-shift time-weighted average, 2.86 ppm for unloading, and 0.54 ppm for loading. For bulk terminal drivers, the mean benzene level without vapor control was 0.12 ppm for time weighted average, 0.24 ppm for unloading, and 0.33 ppm for loading. The time-weighted average exposure of the agency and bulk terminal drivers based on the data collected and the lognormal model can be expected to exceed threshold limit value-time weighted average of 0.5 ppm for benzene about 70 and 2% of the time, respectively. Agency drivers' unloading and loading tasks accounted for approximately 30% and 7% of the total time, and 95% and 4% of total exposure, respectively. For the bulk terminal drivers, mean unloading and loading tasks constituted 24% and 12% of the total time, and 68% and 19% of the total exposure, respectively. Travel activity accounted for an average of 63% of the total time for agency and 64% for bulk terminal drivers, but only contributed < 1 and 13% of the total exposure, respectively. The actual job-based time-weighted average concentration and the calculated time-weighted average derived from the time-weighted summation of the components tasks are in very good agreement. Within-worker variability was generally higher than between-worker variability. Exposure control strategies are required primarily for unloading at the agencies. Vapor control technology at the terminal effectively reduces exposure (by almost 50%) and fugitive emissions. PMID:15673093

Verma, Dave K; Cheng, Wai K; Shaw, Don S; Shaw, M Lorraine; Verma, Paul; Julian, Jim A; Dumschat, Reinhard E; Mulligan, Sharon J P

2004-11-01

5

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.

2012-10-09

6

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

E-print Network

Pesticide exposure and sprayer's task goals: comparison between vineyards and greenhouses. Mandy of pesticide spraying. The objective of this intervention was to identify factors explaining the influence of task factors on the exposure of greenhouse growers and vineyard workers. Thirteen operators were

7

Pilot task-based assessment of noise levels among firefighters  

PubMed Central

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

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

2012-01-01

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

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

ERIC Educational Resources Information Center

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

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

2009-01-01

10

Task-Based Information Searching.  

ERIC Educational Resources Information Center

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

Vakkari, Pertti

2003-01-01

11

76 FR 72404 - Pesticides: Availability of Pesticide Registration Notice Regarding the Non-Dietary Exposure Task...  

Federal Register 2010, 2011, 2012, 2013

...Availability of Pesticide Registration Notice...the Non-Dietary Exposure Task Force AGENCY...risks to people from exposure to the pesticide in and around the...develop information on exposure to pesticides that can be...

2011-11-23

12

Occupational exposure to asbestos in New South Wales, Australia (1970–1989): development of an asbestos task exposure matrix  

Microsoft Academic Search

ObjectivesTo design and construct a standardised tool to provide exposure information associated with commonly used asbestos products and their related tasks in New South Wales (NSW), Australia.MethodsAsbestos dust exposure measurements taken during workplace inspections in the 1970s and 1980s were collected and stored in an exposure database. Measurements were assigned to specific asbestos product and task groups and divided into

Rebecca A Hyland; Deborah H Yates; Geza Benke; Malcolm Sim; Anthony R Johnson

2010-01-01

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

Fear of blushing: Effects of task concentration training versus exposure in vivo on fear and physiology  

Microsoft Academic Search

Patients with fear of blushing as the predominant complaint (N=31) were randomly assigned to (1) exposure in vivo (EXP), or (2) task concentration training (TCT), in order to test the effect of redirecting attention above exposure only. In addition, it was investigated whether treatment reduced actual blush behavior; therefore, physiological parameters of blushing were measured during two behavioral tests. Half

Sandra Mulkens; Susan M. Bogels; Peter J. De Jong; Judith Louwers

2001-01-01

15

Variation in rat urinary aeroallergen levels explained by differences in site, task and exposure group.  

PubMed

We describe how much of the variation in rat urinary aeroallergen (RUA) levels may be explained by differences in site and exposure group in research establishments and we identify task categories associated with high RUA levels. In this population 73% of the variability in RUA levels could be explained by exposure group, site and their interaction term. Exposure group alone explained the majority of the variation (69%). The task category associated with the highest RUA level was cleaning out, followed by indirect contact with rats and handling rats. The task categories associated with the lowest levels were slide production, post mortem and experiments. These results may help choose appropriate exposure measures for epidemiological studies in research establishments in the future and may help reduce the incidence of laboratory animal allergy. PMID:8588715

Nieuwenhuijsen, M J; Gordon, S; Harris, J M; Tee, R D; Venables, K M; Newman Taylor, A J

1995-12-01

16

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.

17

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

18

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

19

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

PubMed

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

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

2014-12-01

20

Task-based decomposition of factored POMDPs.  

PubMed

Recently, partially observable Markov decision processes (POMDP) solvers have shown the ability to scale up significantly using domain structure, such as factored representations. In many domains, the agent is required to complete a set of independent tasks. We propose to decompose a factored POMDP into a set of restricted POMDPs over subsets of task relevant state variables. We solve each such model independently, acquiring a value function. The combination of the value functions of the restricted POMDPs is then used to form a policy for the complete POMDP. We explain the process of identifying variables that correspond to tasks, and how to create a model restricted to a single task, or to a subset of tasks. We demonstrate our approach on a number of benchmarks from the factored POMDP literature, showing that our methods are applicable to models with more than 100 state variables. PMID:23757544

Shani, Guy

2014-02-01

21

Task Synchronization in Reservation-Based Real-Time Systems  

E-print Network

Task Synchronization in Reservation-Based Real-Time Systems Giuseppe Lipari, Member, IEEE, GerardoWidth Inheritance (BWI) protocol, a new strategy for scheduling real-time tasks in dynamic systems, which extends guarantees becomes a complex problem. In dynamic real-time systems, tasks can be activated dynamically

Lipari, Giuseppe

22

The influence of task and location on solvent exposures in a printing plant.  

PubMed

A work measurement technique was used to monitor the activities of seven printing press operators. Repeated observations were made to learn workers' tasks and workers' locations in the plant, and a photoionization detector was used to measure the instantaneous solvent concentration in each worker's breathing zone. Location data, analyzed using a computer aided design system, did not show any indication that there were high or low exposure areas. Regression, however, showed that a significant amount of variability in a worker's exposures was accounted for by the number of times the worker performed a certain "hazardous task" (r2 = 0.57). The results indicate that it may be possible to simplify industrial hygiene sampling strategies by using work measurement data, such as time study or work sampling, to identify maximum risk employees. PMID:3400590

Hansen, D J; Whitehead, L W

1988-05-01

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

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

25

Ordering design tasks based on coupling strengths  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

26

Ordering Design Tasks Based on Coupling Strengths  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

27

Exploring the Effects of Seated Whole Body Vibration Exposure on Repetitive Asymmetric Lifting Tasks.  

PubMed

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

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

2014-09-29

28

The ability of non-computer tasks to increase biomechanical exposure variability in computer-intensive office work.  

PubMed

Postures and muscle activity in the upper body were recorded from 50 academics office workers during 2 hours of normal work, categorised by observation into computer work (CW) and three non-computer (NC) tasks (NC seated work, NC standing/walking work and breaks). NC tasks differed significantly in exposures from CW, with standing/walking NC tasks representing the largest contrasts for most of the exposure variables. For the majority of workers, exposure variability was larger in their present job than in CW alone, as measured by the job variance ratio (JVR), i.e. the ratio between min-min variabilities in the job and in CW. Calculations of JVRs for simulated jobs containing different proportions of CW showed that variability could, indeed, be increased by redistributing available tasks, but that substantial increases could only be achieved by introducing more vigorous tasks in the job, in casu illustrated by cleaning. PMID:25345757

Barbieri, Dechristian França; Srinivasan, Divya; Mathiassen, Svend Erik; Nogueira, Helen Cristina; Oliveira, Ana Beatriz

2014-10-27

29

Examination of computer task exposures in radiologists: a work systems approach.  

PubMed

Radiologists are intensive computer users as they review and interpret radiological examinations using the Picture Archiving and Communication Systems (PACS). Since their computer tasks require the prolonged use of pointing devices, a high prevalence of Musculoskeletal Disorders (MSDs) is reported. The first phase of this study involved conducting a Cognitive Work Analysis in conjunction with a Participatory Ergonomics approach to perform a total work system analysis. We also conducted an ergonomic survey as well as collected computer use data, specifically for the mouse and keyboard. The goal of the study was to reduce the physical exposures for radiologists. This paper presents Phase I results describing the analyses and redesign process of the radiologists tasks, training design, computer use, and selected survey results. PMID:22316978

Robertson, Michelle M; Boiselle, Philip; Eisenberg, Ronald; Siegal, Dainel; Chang, Che-Hsu Joe; Dainoff, Marvin; Garabet, Angela; Garza, Jennifer Bruno; Dennerlein, Jack

2012-01-01

30

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.

31

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

32

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

33

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.

34

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

35

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

36

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

37

Lead exposure among workers renovating a previously deleaded bridge: comparison of trades, work tasks.  

PubMed

Airborne and surface lead exposures were evaluated for construction trade groups at a previously deleaded bridge renovation site in the midwestern United States. Although all lead-based paint should have been removed, old layers of leaded paint were still present on some sections of the bridge. Ironworkers performing metal torch cutting had the highest exposures (188 microg/m3), followed by workers engaged in clean-up operations and paint removal (p < 0.001). Respirators were most frequently worn by workers with the greatest lead exposures; however, laborers performing clean-up operations had exposures to lead dust of 43 microg/m3 and often wore no respiratory protection. Wipe samples revealed that almost all contractor vehicles were contaminated with lead. Heavy equipment operators with low airborne lead exposure had the highest levels of surface contamination in personal vehicles (3,600 microg/m2). Laborers cleaning structural steel with compressed air and ironworkers exposed to lead fumes from cutting had the highest concentrations of lead dust on clothing (mean 4,766 microg/m2). Handwashing facilities were provided, but were infrequently used. No separate clothes changing facility was available at the site. The potential for "take-home" contamination was high, even though this site was thought to be relatively free of lead. Construction contractors and their workers need to be aware that previous deleading of a site may not preclude exposure to significant amounts of lead. PMID:11192213

Johnson, J C; Reynolds, S J; Fuortes, L J; Clarke, W R

2000-01-01

38

A Multiagent Recommender System with Task-Based Agent Specialization  

NASA Astrophysics Data System (ADS)

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

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

39

'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

40

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

41

A physiological response (plasma cyclic amp) and a psychological response (STAI-A-state) to noise exposure and/or calculation task  

NASA Astrophysics Data System (ADS)

The effects of 90 dB(A) noise exposure and/or a calculation task on plasma cyclic AMP concentrations (physiological index) and STAI-A-State scores (psychological index) in normal subjects are compared. Neither the plasma cyclic AMP concentration nor the STAI-A-State scores showed any significant change in response to the calculation task. STAI-A-State scores increased significantly only in response to 90 dB(A) noise exposure, while both the indices showed significant increases under the effects of both noise exposure and the calculation task. The sensitivity of the rate of increase in plasma cyclic AMP caused by noise exposure plus the calculation task was higher than that of the rate of increase in scores on the A-State scale caused by this noise exposure/task combination. The physiological effect in human subjects of noise exposure became larger when a psychological stress (calculation task) was added.

Iwamoto, M.; Ishii, F.; Yoneda, J.; Morie, T.; Harada, N.

1995-10-01

42

A Task-Based Evaluation of an Aggregated Search Interface  

E-print Network

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

Lalmas, Mounia

43

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

44

Vision-based handling tasks for an autonomous outdoor forklift  

E-print Network

Vision-based handling tasks for an autonomous outdoor forklift C´edric Pradalier CSIRO ICT Centre, Autonomous Systems Laboratory, Brisbane, Australia Summary. In the aluminium industry, Hot Metal Carriers of robust outdoor crucible handling capacities, relying on the autonomous tracking of especially designed

Paris-Sud XI, Université de

45

PHOSPHORUS: A Task-Based Agent Matchmaker Yolanda Gil  

E-print Network

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

Gil, Yolanda

46

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

47

The Suitability of Task-Based Approaches for Secondary Schools: Perspectives from Hong Kong  

ERIC Educational Resources Information Center

Task-based teaching has a high profile within contemporary ELT, yet there are few analyses of the appropriateness of task-based approaches for school contexts. This paper aims to analyse the suitability of task-based teaching for Hong Kong secondary schools; and to derive some suggestions for the development of a version of task-based approaches…

Carless, David

2007-01-01

48

Task-based optimization of image reconstruction in breast CT  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

49

Runtime Task Mapping Based on Hardware Configuration Reuse  

E-print Network

Abstract—In this paper, we propose a new heuristic for runtime task mapping of application(s) onto reconfigurable architectures. The heuristic is based on hardware configuration reuse, which tries to avoid the reconfiguration overhead of few selected tasks, by reusing the hardware configurations already available in the reconfigurable hardware. We evaluate our heuristic by performing a mapping of an extended Motion-JPEG application onto a reconfigurable architecture. A large variety of experiments have been conducted on the proposed algorithm for the same reconfigurable architecture model with different FPGA sizes. The obtained result shows up to 45% performance gain by reusing the hardware configurations as suggested by the proposed heuristic, compared to well-known approaches from the state-of-the-art, which do not take into consideration the hardware configuration reuse. I.

Kamana Sigdel; Carlo Galuzzi; Koen Bertels; Mark Thompson; Andy D. Pimentel

50

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

2014-10-01

51

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

52

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

PubMed

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

53

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

54

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

E-print Network

A Dual-layer CRFs Based Joint Decoding Method for Cascaded Segmentation and Labeling Tasks Yanxin later in the chain to help making better pre- diction of earlier tasks [Sutton and McCallum, 2005a]. Sev to inconsistent results, especially in cases where segmentation task precedes labeling task. We present a method

Pratt, Vaughan

55

Design of Space Shuttle Tile Servicing Robot: An Application of Task Based Kinematic Design  

Microsoft Academic Search

A framework called task based design (TBD) to design an optimal robot manipulator for a given task is proposed. Only kinematic parameters are considered. An optimal manipulator is designed. It performs a given task best by using a framework called progressive design that decomposes the complexity of the task into three steps: kinematic design, planning, and kinematic control. As an

Jin-oh Kim; Pradeep K. Khosla

1993-01-01

56

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

57

Bias in the estimation of exposure effects with individual- or group-based exposure assessment.  

PubMed

In this paper, we develop models of bias in estimates of exposure-disease associations for epidemiological studies that use group- and individual-based exposure assessments. In a study that uses a group-based exposure assessment, individuals are grouped according to shared attributes, such as job title or work area, and assigned an exposure score, usually the mean of some concentration measurements made on samples drawn from the group. We considered bias in the estimation of exposure effects in the context of both linear and logistic regression disease models, and the classical measurement error in the exposure model. To understand group-based exposure assessment, we introduced a quasi-Berkson error structure that can be justified with a moderate number of exposure measurements from each group. In the quasi-Berkson error structure, the true value is equal to the observed one plus error, and the error is not independent of the observed value. The bias in estimates with individual-based assessment depends on all variance components in the exposure model and is smaller when the between-group and between-subject variances are large. In group-based exposure assessment, group means can be assumed to be either fixed or random effects. Regardless of this assumption, the behavior of estimates is similar: the estimates of regression coefficients were less attenuated with a large sample size used to estimate group means, when between-subject variability was small and the spread between group means was large. However, if groups are considered to be random effects, bias is present, even with large number of measurements from each group. This does not occur when group effects are treated as fixed. We illustrate these models in analyses of the associations between exposure to magnetic fields and cancer mortality among electric utility workers and respiratory symptoms due to carbon black. PMID:20179749

Kim, Hyang-Mi; Richardson, David; Loomis, Dana; Van Tongeren, Martie; Burstyn, Igor

2011-01-01

58

Indoor odor exposure effects on psycho-physiological states during intellectual tasks and rest  

Microsoft Academic Search

The responses of five human subjects to two indoor airborne odors (mint and cypress) were examined to determine the effect of perceived air quality and odor type and duration on several psycho-physiological variables during periods of rest and while performing intellectual tasks. An olfactometer system was installed in a climate chamber at the University of Tokyo, with the nozzle located

Kentaro Amano; Hiroki Takahashi; Shinsuke Kato; Hideaki Tani; Takeshi Ishiguro; Masaaki Higuchi; Satoshi Saito; Hiroki Miyata

2012-01-01

59

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

60

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

ERIC Educational Resources Information Center

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

Butler, Yuko Goto; Zeng, Wei

2014-01-01

61

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

62

Sensor network-based multi-robot task allocation  

Microsoft Academic Search

We present DINTA, distributed in-network task allocation - a novel paradigm for multi-robot task allocation (MRTA) where tasks are allocated implicitly to robots by a pre-deployed, static sensor network. Experimental results with a simulated alarm scenario show that our approach is able to compute solutions to the MRTA problem in a distributed fashion. We compared our approach to a strategy

Maxim A. Batalin; Gaurav S. Sukhatme

2003-01-01

63

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

PubMed

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

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

2013-01-01

64

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

65

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

PubMed Central

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

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

2006-01-01

66

A task-based approach for Gene Ontology evaluation  

PubMed Central

Background The Gene Ontology and its associated annotations are critical tools for interpreting lists of genes. Here, we introduce a method for evaluating the Gene Ontology annotations and structure based on the impact they have on gene set enrichment analysis, along with an example implementation. This task-based approach yields quantitative assessments grounded in experimental data and anchored tightly to the primary use of the annotations. Results Applied to specific areas of biological interest, our framework allowed us to understand the progress of annotation and structural ontology changes from 2004 to 2012. Our framework was also able to determine that the quality of annotations and structure in the area under test have been improving in their ability to recall underlying biological traits. Furthermore, we were able to distinguish between the impact of changes to the annotation sets and ontology structure. Conclusion Our framework and implementation lay the groundwork for a powerful tool in evaluating the usefulness of the Gene Ontology. We demonstrate both the flexibility and the power of this approach in evaluating the current and past state of the Gene Ontology as well as its applicability in developing new methods for creating gene annotations. PMID:23734599

2013-01-01

67

Linguistic Characteristics of ESL Writing in Task-based E-mail Activities.  

ERIC Educational Resources Information Center

Investigated the efficacy of integrating task-based e-mail activities into a process-oriented English-as-Second-Language (ESL) writing class. Particular focus was on the linguistic characteristics of 132 pieces of e-mail writing by ESL students in tasks that differed in terms of purpose, audience interaction, and task structure. Computerized text…

Li, Yili

2000-01-01

68

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

ERIC Educational Resources Information Center

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

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

69

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

70

Exposure  

MedlinePLUS

... from a site? Reference Section 1. What is environmental exposure? Environmental exposure occurs when you contact a ... of Page 4. Will I get sick from environmental exposure? Being exposed does not mean you will ...

71

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

72

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

73

Price-Based Dynamic Task Allocation Using Fuzzy Logic  

Microsoft Academic Search

Task allocation in a dynamic environment where workers have different capabilities and these capabilities may change over time is a common problem in today's manufacturing. Capabilities of workers may change over time because of their usage i.e. performance of a machine may decrease over time because of being overloaded or its performance may increase because of chan ging its parts

Mohsen Talaei; Caro Lucas

74

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

75

Task based groupware design: putting theory into practice  

Microsoft Academic Search

Designing Groupware systems requires methods and tools that cover all aspects of Groupware systems. We present a method that utilizes known theoretical insights and makes them usable in practice. In our method, the design of Groupware systems is driven by an extensive task analysis followed by structured design and iterative evaluation using usability criteria. Using a combination of multiple complementary

Gerrit C. van der Veer; Martijn van Welie

2000-01-01

76

Linguistic characteristics of ESL writing in task-based e-mail activities  

Microsoft Academic Search

This study investigated the efficacy of integrating task-based e-mail activities into a process-oriented ESL writing class. In particular, it examined the linguistic characteristics of 132 pieces of e-mail writing by ESL students in tasks that differed in terms of purpose, audience interaction and task structure. The analysis focused on the linguistic features of the students' e-mail writing at different levels,

Yili Li

2000-01-01

77

A Guide for the Management of Special Education Programs. 2.0 Procedures for Use of the Task Base Composite.  

ERIC Educational Resources Information Center

The second volume of an eight-part series on a task-based management system for special education programs offers detailed procedures for use of the task base composite (TBC), a listing of approximately 700 task descriptions classified under 20 functions and divided according to whether the task is necessary to support a program or directly…

Santa Cruz County Superintendent of Schools, CA.

78

Risk-based indicators of Canadians’ exposures to environmental carcinogens  

PubMed Central

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

2013-01-01

79

Prediction Task Assignment of Multi-UAV Approach Based on Consensus  

NASA Astrophysics Data System (ADS)

In the battlefield, UAV (Unmanned Aerial Vehicle) needs to assign tasks dynamically by using the radar tracking information, but when the poor weather comes, or UAV enters blind area, the radar cannot gather the accurate information which severely impair the assignment result. A new task assignment prediction method was proposed in this paper. We first predict the UAV information using UKF (Unscented Kalman Filter) algorithm, and then clear up the collision by auction algorithm. Finally, we assign the tasks. The results show that the algorithm performs better than greedy task assignment and consensus based auction algorithm.

Chen, Chen; Qin, Zheng; Xing, Jian-Kuan

80

Analysing Engineering Tasks Using a Hybrid Machine Vision and Knowledge Based System Application  

E-print Network

tasks, which is learned by our system from input sequences annotated by profes- sional civil engineersAnalysing Engineering Tasks Using a Hybrid Machine Vision and Knowledge Based System Application Ioannis Kaloskampis 1,2 , Yulia A. Hicks 1 , and David Marshall2 1 School of Engineering, Cardiff

Martin, Ralph R.

81

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

ERIC Educational Resources Information Center

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

Bowman, Caroline H.; Turnbull, Oliver H.

2004-01-01

82

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

ERIC Educational Resources Information Center

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

Salmani-Nodoushan, Mohammad Ali

2005-01-01

83

Task based model for rcit generation from sensor data: an early experiment  

E-print Network

Task based model for récit generation from sensor data: an early experiment Belén A. Baez Miranda1, we present a task model used for automatic story generation from real data focusing on the narrative planning. The aim is to generate récits (stories) from sensors data acquired during a ski sortie. The model

Paris-Sud XI, Université de

84

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

85

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

86

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

87

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

88

Establishing aerosol exposure predictive models based on vibration measurements.  

PubMed

This paper establishes particulate exposure predictive models based on vibration measurements under various concrete drilling conditions. The whole study was conducted in an exposure chamber using a full-scale mockup of concrete drilling simulator to simulate six drilling conditions. For each drilling condition, the vibration of the three orthogonal axes (i.e., a(x), a(y), and a(z)) was measured from the hand tool. Particulate exposure concentrations to the total suspended particulate (C(TSP)), PM(10) (C(PM10)), and PM(2.5) (C(PM2.5)) were measured at the downwind side of the drilling simulator. Empirical models for predicting C(TSP), C(PM10) and C(PM2.5) were done based on measured a(x), a(y), and a(z) using the generalized additive model. Good agreement between measured aerosol exposures and vibrations was found with R(2)>0.969. Our results also suggest that a(x) was mainly contributed by the abrasive wear. On the other hand, a(y) and a(z) were mainly contributed by both the impact wear and brittle fracture wear. The approach developed from the present study has the potential to provide a cheaper and convenient method for assessing aerosol exposures from various emission sources, particularly when conducting conventional personal aerosol samplings are not possible in the filed. PMID:20153113

Soo, Jhy-Charm; Tsai, Perng-Jy; Lee, Shih-Chuan; Lu, Shih-Yi; Chang, Cheng-Ping; Liou, Yuh-When; Shih, Tung-Sheng

2010-06-15

89

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

90

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

91

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

92

Optimal Reward-Based Scheduling for Periodic Real-Time Tasks  

Microsoft Academic Search

Abstract Reward-based scheduling refers to the problem,in which there is a reward,associated with the execution of a task. In our framework, each real-time task comprises a manda- tory and an optional part, with which a nondecreasing reward function is associated. Imprecise Computation and Increased- Reward-with-Increased-Service models fall within the scope of this framework. In this paper, we address the reward-based

Hakan Aydin; Rami G. Melhem; Daniel Mossé; Pedro Mejía-alvarez

2001-01-01

93

TESS-based dose-response using pediatric clonidine exposures  

SciTech Connect

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

Benson, Blaine E. [New Mexico Poison and Drug Information Center and University of New Mexico College of Pharmacy, Albuquerque, NM 87131 (United States)]. E-mail: jebenson@salud.unm.edu; Spyker, Daniel A. [Alexza Pharmaceuticals, Palo Alto, CA 94303 (United States); Troutman, William G. [University of New Mexico College of Pharmacy, Albuquerque, NM 87131 (United States); Watson, William A. [American Association of Poison Control Centers, Washington, DC 20016 (United States)]. E-mail: http://www.aapcc.org/

2006-06-01

94

Task Scheduling Based On Thread Essence and Resource Limitations  

E-print Network

threads as interactive, or IO-bound, when their sleep time, which is the time threads voluntarily release co-scheduling threads based on cache usage. Zhuravlev et al. [28] suggest co- scheduling threads

Kolodny, Avinoam

95

Optimal Reward-Based Scheduling of Periodic Real-Time Tasks  

Microsoft Academic Search

Reward-based scheduling refers to the problem in which there is a reward associated with the execution of a task. In our framework, each real-time task comprises a manda- tory and an optional part, with which a nondecreasing reward function is associated. Imprecise Computation and Increased- Reward-with-Increased-Service models fall within the scope of this framework. In this paper, we address the

Hakan Aydin; Rami G. Melhem; Daniel Mossé; Pedro Mejía-alvarez

1999-01-01

96

Optimal Reward-Based Scheduling of Periodic Real-Time Tasks  

Microsoft Academic Search

Reward-based scheduling refers to the problem in which there is a reward associated with the execution of a task. In our framework, each real-time task comprises a manda- tory and an optional part, with which a nondecreasing reward function is associated. Imprecise computation and Increas ed- Reward-with-Increased-Service models fall within the sco pe of this framework. In this paper, we

Hakan Aydin; Pedro Mejia-Alvarez; Rami Melhem; Daniel Mosse

97

Sensitivity analysis of knapsack-based task scheduling on the grid  

Microsoft Academic Search

The knapsack-based task scheduler has been previously sho- wn to provide Quality of Service to malleable tasks on com- putational grids. In this study, we measure the sensitivity of the knapsack-derived schedules to variations in the pre- scribed allocation policies and their corresponding utility functions. In particular, we explore the effects of varying the strengths of an external user-specified monetary

Daniel C. Vanderster; Nikitas J. Dimopoulos

2006-01-01

98

Task based kinematic design of a two DOF manipulator with a parallelogram five-bar link mechanism  

Microsoft Academic Search

As the demand for modular manipulators or special purpose manipulators has increased, task based design to design an optimal manipulator for given tasks become more and more important. However, manipulator design problems usually are very complex due to a large number of design parameters, their nonlinear and implicit relationship, and so on. To achieve task based design successfully, it is

J. Y. Kim

2006-01-01

99

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

100

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

101

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

ERIC Educational Resources Information Center

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

Kenning, Marie-Madeleine

2010-01-01

102

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

103

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

104

Task-based optimization and performance assessment in optical coherence imaging.  

PubMed

Optimization of an optical coherence imaging (OCI) system on the basis of task performance is a challenging undertaking. We present a mathematical framework based on task performance that uses statistical decision theory for the optimization and assessment of such a system. Specifically, we apply the framework to a relatively simple OCI system combined with a specimen model for a detection task and a resolution task. We consider three theoretical Gaussian sources of coherence lengths of 2, 20, and 40 microm. For each of these coherence lengths we establish a benchmark performance that specifies the smallest change in index of refraction that can be detected by the system. We also quantify the dependence of the resolution performance on the specimen model being imaged. PMID:15984486

Rolland, Jannick; O'Daniel, Jason; Akcay, Ceyhun; DeLemos, Tony; Lee, Kye S; Cheong, Kit-Iu; Clarkson, Eric; Chakrabarti, Ratna; Ferris, Robert

2005-06-01

105

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

NASA Astrophysics Data System (ADS)

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

Yi, Daqing; Goodrich, Michael A.

2014-06-01

106

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

107

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

108

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

109

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

PubMed

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

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

2014-02-01

110

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

111

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

112

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

113

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

ERIC Educational Resources Information Center

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

Clariana, Roy B.; Lee, Doris

2001-01-01

114

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

E-print Network

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

Ackerman, Mark S.

115

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

116

Task-Based Authorization Controls (TBAC): A Family of Models for Active and Enterprise-Oriented Autorization Management  

Microsoft Academic Search

In this paper, we develop a new paradigm for access control and authorization management, called task-based authorization controls (TBAC). TBAC models access controls from a task-oriented perspective than the traditional subject-object one. Access mediation now involves authorizations at various points during the completion of tasks in accordance with some application logic. By taking a task- oriented view of access control

Roshan K. Thomas; Ravi S. Sandhu

1997-01-01

117

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

118

Development of lead source-specific exposure standards based on aggregate exposure assessment: Bayesian inversion from biomonitoring information to multipathway exposure.  

PubMed

Exposure of children to lead is of great concern, and the exposure standards for different media are important for protecting public safety. However, these media-specific standards often fail to ensure the safety of children even when environmental lead levels are lower than the quality standards since humans are often exposed to lead via multiple pathways. To establish exposure standards to protect children from hazards associated with exposure to lead, an analytical tool for assessing aggregate exposure to lead based on Bayesian hierarchical model was developed, and then was used to update the external lead exposure of diet, paint, soil, air and drinking water using the blood lead levels in Chinese children aged 1-6 years. On the basis of updated external exposure, the source allocations for diet, paint, soil, air, and drinking water in China were 65.80 ± 7.92%, 16.98 ± 7.88%, 13.65 ± 5.05%, 3.36 ± 1.75%, and 0.20 ± 0.14%, respectively. Based on the estimated source allocations, the exposure standards were evaluated to be 0.2 ?g/m(3), 24.25 mg/kg, 0.027 ?g/L, 0.051 ?g/mg, 0.042 ?g/mg, 38.02 ?g/mg for air, soil, water, grains, vegetables, and paint, respectively. Since the standards setting procedure was based on the multipathway aggregate exposure assessment of lead, the newly proposed exposure standards should ensure the safety of children. PMID:22142206

Dong, Zhaomin; Hu, Jianying

2012-01-17

119

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

120

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks  

E-print Network

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks D dynamical systems and systems identification we develop a framework for the study of primitives for human motion, which we refer to as movemes. The objective is understanding human motion by decomposing

Murray, Richard M.

121

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks  

E-print Network

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks D dynamical systems and systems identification we develop a framework for the study of primitives for human with respect to noise and model uncertainty. We test our ideas on data sampled from five human subjects who

Murray, Richard M.

122

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks  

E-print Network

Decomposition of Human Motion into Dynamics Based Primitives with Application to Drawing Tasks develop a framework for the study of primitives for human motion, which we refer to as movemes. The objective is understanding human motion by decomposing it into a sequence of elementary building blocks

Perona, Pietro

123

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

ERIC Educational Resources Information Center

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

Yanguas, Inigo

2012-01-01

124

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

125

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.

126

SDMOQL: An OQL-based Data Mining Query Language for Map Interpretation Tasks  

E-print Network

SDMOQL: An OQL-based Data Mining Query Language for Map Interpretation Tasks Donato Malerba, 70125 Bari, Italy {malerba, appice, vacca}@di.uniba.it Abstract. Spatial data mining denotes. An important application of spatial data mining methods is the extraction of knowledge from a Geographic

Malerba, Donato

127

Task-oriented Design of Concentric Tube Robots using Mechanics-based Models  

E-print Network

-specific and surgery-specific basis to enable the robot to reach multiple clinically relevant sites while avoiding of a concentric tube robot on a patient- and surgery-specific basis to enable a single robot insertedTask-oriented Design of Concentric Tube Robots using Mechanics-based Models Luis G. Torres, Robert

Alterovitz, Ron

128

Combination of Task Description Strategies and Case Base Properties for Meta-Learning  

E-print Network

characterization (which we will refer to as DCT due to the name of a software used to compute the characteristics will dwell on the case properties extracted from case bases to evaluate their quality by possible conflicts, the last section summarizes the paper and points at future work. 2 Task Description Strategies Probably

Bohanec, Marko

129

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

130

Assessing Primary Students' Knowledge of Networks, Hierarchies and Matrices using Scenario-Based Tasks  

Microsoft Academic Search

This paper investigated primary students' ( N = 127) knowledge of the properties of Networks, Hierarchies, and Matrices using a set of scenario-based tasks. Firstly, the results revealed differences in students' knowledge of the various properties for each diagram, and differences in their knowledge of some properties a cross the various diagrams. Secondly and unexpectedly, the performance of older students

Carmel Diezmann

131

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}@swin.edu.au ABSTRACT Cloud computing delivers IT solutions as a utility to users. One consequence of this model. We have developed an energy consumption model for cloud computing systems. To operationalise

Schneider, Jean-Guy

132

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

ERIC Educational Resources Information Center

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

Zheng, Xinmin; Borg, Simon

2014-01-01

133

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

Microsoft Academic Search

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

Charles E. Pippin; Henrik Christensen

2011-01-01

134

Task based design of modular robot manipulator using efficient genetic algorithm  

Microsoft Academic Search

A modular robot manipulator is a robotic system assembled from discrete joints and links into one of many possible manipulator configurations. This paper describes a task based design method of modular robot manipulators. A locking mechanism which provides quick coupling and decoupling is developed and a parallel connection method is devised reducing the number of components on each module. To

W. K. Chung; Jeongheon Han; Y. Youm; S. H. Kim

1997-01-01

135

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

136

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

SciTech Connect

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

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

2011-11-15

137

Performance monitoring and analysis of task-based OpenMP.  

PubMed

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

138

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

139

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

140

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

141

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

142

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

143

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

144

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

145

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

PubMed

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

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

2012-01-01

146

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

147

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

148

do NOT use any Footer it will be added by us later A Logo-based Task for Arithmetical Activity  

E-print Network

do NOT use any Footer ­ it will be added by us later A Logo-based Task for Arithmetical Activity later INTRODUCTION Arithmetic is about performing computations in order to get a result (Hewitt, 1998 report here on the trialling of a Logo-based task (see screenshot below) designed to foster meaningful

Boyer, Edmond

149

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

PubMed

A number of recent studies have demonstrated that near-infrared spectroscopy (NIRS) is a promisingneuroimaging modality for brain-computer interfaces (BCIs). So far, most NIRS-based BCI studies have focusedon enhancing the accuracy of the classification of different mental tasks. In the present study, we evaluated theperformances of a variety of mental task combinations in order to determine the mental task pairs that are bestsuited for customized NIRS-based BCIs. To this end, we recorded event-related hemodynamic responses whileseven participants performed eight different mental tasks. Classification accuracies were then estimated for allpossible pairs of the eight mental tasks (8C2 = 28). Based on this analysis, mental task combinations with relatively high classification accuracies frequently included the following three mental tasks: “mental multiplication,” “mental rotation,” and “right-hand motor imagery.” Specifically, mental task combinations consisting of two of these three mental tasks showed the highest mean classification accuracies. It is expected that our results will be a useful reference to reduce the time needed for preliminary tests when discovering individual-specific mental task combinations. PMID:25036216

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

2014-07-01

150

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

151

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.

152

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

NASA Astrophysics Data System (ADS)

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

Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

2012-01-01

153

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

NASA Astrophysics Data System (ADS)

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

Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

2011-12-01

154

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

155

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

156

Regressor-free force\\/position control of fixed-base exoskeletons for rehabilitation tasks  

Microsoft Academic Search

The required tasks in fixed-base exoskeletons demand a fast position\\/force controller; yet robust against unknown disturbances due to the application itself is tightly coupled with a human in a wide range of operational conditions, which give rise to human-exoskeleton interaction dynamics, high nonlinear uncertain exoskeleton dynamics, noisy sensors and other parametric uncertainties, such as environmental contacts. These factors do not

Luis Ivan Lugo-villeda; Antonio Frisoli; Vicente Parra-vega; Massimo Bergamasco

2009-01-01

157

Fabricating Composite Materials-A Comprehensive Problem-Solving Architecture Based on Generic Tasks  

Microsoft Academic Search

A problem-solving architecture that addresses the entire life cycle of composite-materials fabrication from a generic-task viewpoint is presented. Prototype systems that capture the experience-based static design of fabrication plans and the progress-control knowledge of cavity tuning for the microwave curing of composites are described. The capturing of compiled process planning in the plan design phase, the routine-design system, and monitoring,

Jon Sticklen; Ahmed Kamel; Martin C. Hawley; Valerie Adegbite

1992-01-01

158

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

159

Fast Gaussian kernel learning for classification tasks based on specially structured global optimization.  

PubMed

For a practical pattern classification task solved by kernel methods, the computing time is mainly spent on kernel learning (or training). However, the current kernel learning approaches are based on local optimization techniques, and hard to have good time performances, especially for large datasets. Thus the existing algorithms cannot be easily extended to large-scale tasks. In this paper, we present a fast Gaussian kernel learning method by solving a specially structured global optimization (SSGO) problem. We optimize the Gaussian kernel function by using the formulated kernel target alignment criterion, which is a difference of increasing (d.i.) functions. Through using a power-transformation based convexification method, the objective criterion can be represented as a difference of convex (d.c.) functions with a fixed power-transformation parameter. And the objective programming problem can then be converted to a SSGO problem: globally minimizing a concave function over a convex set. The SSGO problem is classical and has good solvability. Thus, to find the global optimal solution efficiently, we can adopt the improved Hoffman's outer approximation method, which need not repeat the searching procedure with different starting points to locate the best local minimum. Also, the proposed method can be proven to converge to the global solution for any classification task. We evaluate the proposed method on twenty benchmark datasets, and compare it with four other Gaussian kernel learning methods. Experimental results show that the proposed method stably achieves both good time-efficiency performance and good classification performance. PMID:24929345

Zhong, Shangping; Chen, Tianshun; He, Fengying; Niu, Yuzhen

2014-09-01

160

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

SciTech Connect

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

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

2011-09-25

161

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

PubMed Central

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

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

2013-01-01

162

Factors affecting outdoor exposure in winter: population-based study  

NASA Astrophysics Data System (ADS)

The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study ( n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

Mäkinen, Tiina M.; Raatikka, Veli-Pekka; Rytkönen, Mika; Jokelainen, Jari; Rintamäki, Hannu; Ruuhela, Reija; Näyhä, Simo; Hassi, Juhani

2006-09-01

163

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

164

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

ERIC Educational Resources Information Center

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

Arslanyilmaz, Abdurrahman

2012-01-01

165

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

166

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

167

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

PubMed Central

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

Vermeulen, R; Kromhout, H

2005-01-01

168

Beyond TPH: health-based evaluation of petroleum hydrocarbon exposures.  

PubMed

The term "total petroleum hydrocarbons" (TPH) is a widely used, but loosely defined, parameter quantified by a number of different methodologies for expressing the aggregate amount of petroleum hydrocarbon compounds (PHCs) in a sample. Because of the shortcomings associated with comparing data from different methods, and the difficulty of assessing potential toxicities of complex mixtures of hydrocarbons, a new approach at more fully and explicitly defining the PHC composition of samples and predicting human noncancer health risks from those exposures has been developed. This new approach is the subject of this paper. This method can be used to perform site-specific risk assessments or to develop health-based cleanup standards for petroleum hydrocarbons. The technique divides the broad chemical classes of PHC (i.e., saturated versus unsaturated) into subgroups of compounds based on numbers of carbon atoms in the compounds within each subgroup. The mass of compounds in each subgroup is then translated into discrete estimates of health risk for specified exposure scenarios. The subgroups were identified from qualitative and quantitative changes in the nature of noncancer toxicities recorded in the literature. For saturated compounds, toxicity changes as carbon chain length increases (measured by numbers of carbon atoms). A "reference compound" was chosen for each range of compounds, usually because its toxicity was relatively well characterized. A published oral reference dose (RfD) was identified for these compounds, or in the absence of a published value, an oral dose-response value was developed from available toxicity information. For saturated PHCs (alkanes, cycloalkanes, and isoalkanes) the subgroups' reference compounds and assigned toxicity value used are C5 to C8 (n-hexane, 0.06 mg/kg/day); C9 to C18 (n-nonane, 0.6 mg/kg/day); and C19 to C32 (eicosane, 6.0 mg/kg/day). For unsaturated compounds (aromatics), one reference RfD was identified for all compounds: C9 through C32 (pyrene, 0.03 mg/kg/day). Dependent upon the analytical technique used for separation of compounds, the unsaturated alkenes may be grouped and subsequently quantified with either the saturate or unsaturate groups. The implications of possible association with either group and contributions to risk estimates are probably not significant. Alkenes make up a small fraction of most fuel products, and they bear structural similarity to the alkanes and are not particularly toxicologically active. If grouped analytically with the aromatics the alkene contribution to toxicity estimates would likely be minor and not be an underestimate of its true toxicity. The mass of PHC in each segment of a chromatogram is quantified and converted to a medium-specific concentration which is then entered into standard medium intake equations to arrive at a daily dose of PHC. This dose is then used with the toxicity value identified for the particular segment of the chromatogram to derive a hazard quotient. The quotients can then be summed across fractions to yield a total hazard index. The noncancer health risks from the aromatics benzene, toluene, and xylenes are evaluated separately using standard risk assessment techniques. PMID:8921548

Hutcheson, M S; Pedersen, D; Anastas, N D; Fitzgerald, J; Silverman, D

1996-08-01

169

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. ...

170

Determination of the general public exposure around GSM and UMTS base stations.  

PubMed

This paper summarises two studies, in which measurement and calculation methods to determine the exposure of the general public around GSM and UMTS base stations have been developed and applied to different scenarios. The electromagnetic field variations around the stations in space and time are accounted for by appropriate maximisation techniques. Measurements show a bandwidth of exposures from 0.01% to more than 10% of field strength exposure limits. The distance to the station is not a main influencing factor, whereas the orientation to the main lobe and the sight conditions greatly influence exposure. Several commercially available numerical simulation tools were tested for their applicability on exposure forecast. In line-of-sight scenarios, all programs are able to predict the exposure accurately, whereas in non-line-of-sight situations, free space models overestimate the real exposure by some orders of magnitude. PMID:17933788

Bornkessel, Christian; Schubert, Markus; Wuschek, Matthias; Schmidt, Peter

2007-01-01

171

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

PubMed Central

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

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

2013-01-01

172

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

PubMed

ABSTRACT. Near-infrared spectroscopy (NIRS) is a developing and promising functional brain imaging technology. Developing data analysis methods to effectively extract meaningful information from collected data is the major bottleneck in popularizing this technology. In this study, we measured hemodynamic activity of the prefrontal cortex (PFC) during a color-word matching Stroop task using NIRS. Hemispheric lateralization was examined by employing traditional activation and novel NIRS-based connectivity analyses simultaneously. Wavelet transform coherence was used to assess intrahemispheric functional connectivity. Spearman correlation analysis was used to examine the relationship between behavioral performance and activation/functional connectivity, respectively. In agreement with activation analysis, functional connectivity analysis revealed leftward lateralization for the Stroop effect and correlation with behavioral performance. However, functional connectivity was more sensitive than activation for identifying hemispheric lateralization. Granger causality was used to evaluate the effective connectivity between hemispheres. The results showed increased information flow from the left to the right hemispheres for the incongruent versus the neutral task, indicating a leading role of the left PFC. This study demonstrates that the NIRS-based connectivity can reveal the functional architecture of the brain more comprehensively than traditional activation, helping to better utilize the advantages of NIRS. PMID:24862561

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

2014-05-01

173

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

174

Adaptation of a clustered lumpy background model for task-based image quality assessment in x-ray phase-contrast mammography  

PubMed Central

Purpose: Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM would have been conducted with human readers. These studies have been limited, however, in part due to the large parameter-space of PCM system configurations and the difficulty of employing expert readers for large-scale studies. It has been proposed that numerical observers can be used to approximate the statistical performance of human readers, thus enabling the study of task-based performance over a large parameter-space. Methods: Methods are presented for task-based image quality assessment of PCM images with a numerical observer, the most significant of which is an adapted lumpy background from the conventional mammography literature that accounts for the unique wavefield propagation physics of PCM image formation and will be used with a numerical observer to assess image quality. These methods are demonstrated by performing a PCM task-based image quality study using a numerical observer. This study employs a signal-known-exactly, background-known-statistically Bayesian ideal observer method to assess the detectability of a calcification object in PCM images when the anode spot size and calcification diameter are varied. Results: The first realistic model for the structured background in PCM images has been introduced. A numerical study demonstrating the use of this background model has compared PCM and conventional mammography detection of calcification objects. The study data confirm the strong PCM calcification detectability dependence on anode spot size. These data can be used to balance the trade-off between enhanced image quality and the potential for motion artifacts that comes with use of a reduced spot size and increased exposure time. Conclusions: A method has been presented for the incorporation of structured breast background data into task-based numerical observer assessment of PCM images. The method adapts conventional background simulation techniques to the wavefield propagation physics necessary for PCM imaging. This method is demonstrated with a simple detection task. PMID:22320800

Zysk, Adam M.; Brankov, Jovan G.; Wernick, Miles N.; Anastasio, Mark A.

2012-01-01

175

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

176

Imaging tasks scheduling for high-altitude airship in emergency condition based on energy-aware strategy.  

PubMed

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

177

Diagnostic Ionizing Radiation Exposure in a Population-Based Sample of Children With Inflammatory Bowel Diseases  

Microsoft Academic Search

OBJECTIVES:The degree of diagnostic radiation exposure in children with inflammatory bowel diseases (IBD) is largely unknown. In this study, we describe this exposure in a population-based sample of children with IBD and determine the characteristics associated with moderate radiation exposure.METHODS:We ascertained radiological study use, demographic characteristics, IBD medication use, and the requirement for hospitalization, emergency department (ED) encounter, or inpatient

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

2009-01-01

178

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

179

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...

180

Metaheuristic Based Scheduling Meta-Tasks in Distributed Heterogeneous Computing Systems  

PubMed Central

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

181

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

182

Biology Based Lung Cancer Model for Chronic Low Radon Exposures  

NASA Astrophysics Data System (ADS)

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.

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

2008-08-01

183

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

184

An exposure assessment survey of the Mont Belvieu polyethylene plant  

E-print Network

. Division Department Work Area Worker Group Group/ Task Agent Exposure Indicator Substance RV Rating Basis Group Overall LTA (A-E) TWA STEL IDLH (A-E) (A-E) A/E Task Ad/ustment Freq. Skm Ing. Code Y/N Y/N 1-4 PPE Code Fmal Ratin H... rating was based on a full-shift Time-Weighted Average (TWA), Short-Term Exposure Limit (STEL), and/or whether the exposure indicator was Immediately Dangerous to Life and Health (IDLH). Tasks that resulted in a significant full-shift exposure were...

Tucker, Thomas Franklin

1997-01-01

185

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

E-print Network

Abstract-- Evidence-based medicine is a new direction in modern healthcare. Its task is to prevent warehouse that facilitates evidence-based medicine is a reliable, powerful and user-friendly platform medicine. Keywords--data mining, data warehousing, decision-support systems, evidence-based medicine. I

186

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

187

Tactile refreshable screen based on magneto-rheological fluids for map exploration and navigation tasks  

NASA Astrophysics Data System (ADS)

Human-machine interfaces can convey information via visual, audio and/or haptic cues during a navigation task. The visual and audio technologies are mature, whereas research has to be focused on haptic technologies for mobile devices. In this work, a tactile refreshable screen is proposed which allows its user the exploration of maps and navigational tasks in an egocentric perspective. The proposed device consists of an array of actuators which can display various patterns. The actuation technology is based on a magneto-rheological fluid which is injected in a chamber with an elastomeric membrane using a micro pump. The fluid pressure deforms the membrane in order to display a pattern. The fluid properties are used to form a valve in each cell. A permanent magnet, a ferromagnetic core, and a coil form a closed magnetic circuit with a gap where the magneto-rheological fluid can flow; the magnetic field interacts with the fluid and prevents the filling or draining of the chamber. Applying a current to the coil counteracts the magnetic field generated by the magnet and the fluid can circulate freely in order to inflate or deflate the membrane. The design, fabrication and integration of the device in addition to the results of finite element simulations and experimental measurements are reported.

Bolzmacher, C.; Changeon, G.; Plaud, V.; Roselier, S.; Lozada, J.; Hafez, M.

2011-06-01

188

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

189

Occupational exposure limits for 30 organophosphate pesticides based on inhibition of red blood cell acetylcholinesterase  

Microsoft Academic Search

Toxicity and other relevant data for 30 organophosphate pesticides were evaluated to suggest inhalation occupational exposure limits (OELs), and to support development of a risk assessment strategy for organophosphates in general. Specifically, the value of relative potency analysis and the predictability of inhalation OELs by acute toxicity measures and by repeated oral exposure NOELs was assessed. Suggested OELs are based

Jan E Storm; Karl K Rozman; John Doull

2000-01-01

190

Measuring novices' field mapping abilities using an in-class exercise based on expert task analysis  

NASA Astrophysics Data System (ADS)

We are interested in developing a model of expert-like behavior for improving the teaching methods of undergraduate field geology. Our aim is to assist students in mastering the process of field mapping more efficiently and effectively and to improve their ability to think creatively in the field. To examine expert-mapping behavior, a cognitive task analysis was conducted with expert geologic mappers in an attempt to define the process of geologic mapping (i.e. to understand how experts carry out geological mapping). The task analysis indicates that expert mappers have a wealth of geologic scenarios at their disposal that they compare against examples seen in the field, experiences that most undergraduate mappers will not have had. While presenting students with many geological examples in class may increase their understanding of geologic processes, novices still struggle when presented with a novel field situation. Based on the task analysis, a short (45-minute) paper-map-based exercise was designed and tested with 14 pairs of 3rd year geology students. The exercise asks students to generate probable geologic models based on a series of four (4) data sets. Each data set represents a day’s worth of data; after the first “day,” new sheets simply include current and previously collected data (e.g. “Day 2” data set includes data from “Day 1” plus the new “Day 2” data). As the geologic complexity increases, students must adapt, reject or generate new geologic models in order to fit the growing data set. Preliminary results of the exercise indicate that students who produced more probable geologic models, and produced higher ratios of probable to improbable models, tended to go on to do better on the mapping exercises at the 3rd year field school. These results suggest that those students with more cognitively available geologic models may be more able to use these models in field settings than those who are unable to draw on these models for whatever reason. Giving students practice at generating geologic models to explain data may be useful in preparing our students for field mapping exercises.

Caulkins, J. L.

2010-12-01

191

A distributed computing environment with support for constraint-based task scheduling and scientific experimentation  

SciTech Connect

This paper describes a computing environment which supports computer-based scientific research work. Key features include support for automatic distributed scheduling and execution and computer-based scientific experimentation. A new flexible and extensible scheduling technique that is responsive to a user`s scheduling constraints, such as the ordering of program results and the specification of task assignments and processor utilization levels, is presented. An easy-to-use constraint language for specifying scheduling constraints, based on the relational database query language SQL, is described along with a search-based algorithm for fulfilling these constraints. A set of performance studies show that the environment can schedule and execute program graphs on a network of workstations as the user requests. A method for automatically generating computer-based scientific experiments is described. Experiments provide a concise method of specifying a large collection of parameterized program executions. The environment achieved significant speedups when executing experiments; for a large collection of scientific experiments an average speedup of 3.4 on an average of 5.5 scheduled processors was obtained.

Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L. [Univ. of Washington, Seattle, WA (United States). Dept. of Computer Science and Engineering

1997-04-01

192

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

193

Lunar base scenario cost estimates: Lunar base systems study task 6.1  

NASA Technical Reports Server (NTRS)

The projected development and production costs of each of the Lunar Base's systems are described and unit costs are estimated for transporting the systems to the lunar surface and for setting up the system.

1988-01-01

194

Integration of base rates and new information in an abstract hypothesis-testing task.  

PubMed

In two studies, we investigated how people use base rates and the presence versus the absence of new information to judge which of two hypotheses is more likely. Participants were given problems based on two decks of cards printed with 0-4 letters. A table showed the relative frequencies of the letters on the cards within each deck. Participants were told the letters that were printed on or absent from a card the experimenter had drawn. Base rates were conveyed by telling participants that the experimenter had chosen the deck by drawing from an urn containing, in different proportions, tickets marked either 'deck 1' or 'deck 2'. The task was to judge from which of the two decks the card was most likely drawn. Prior probabilities and the evidential strength of the subset of present clues (computed as 'weight of evidence') were the only significant predictors of participants' dichotomous (both studies) and continuous (Study 2) judgments. The evidential strength of all clues was not a significant predictor of participants' judgments in either study, and no significant interactions emerged. We discuss the results as evidence for additive integration of base rates and the new present information in hypothesis testing. PMID:23560666

Rusconi, Patrice; Marelli, Marco; Russo, Selena; D'Addario, Marco; Cherubini, Paolo

2013-05-01

195

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

196

Survey of RF exposure levels from mobile telephone base stations in Australia.  

PubMed

This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit. PMID:16283652

Henderson, S I; Bangay, M J

2006-01-01

197

A comparison of Bayesian hierarchical modeling with group-based exposure assessment in occupational epidemiology.  

PubMed

We build a Bayesian hierarchical model for relating disease to a potentially harmful exposure, by using data from studies in occupational epidemiology, and compare our method with the traditional group-based exposure assessment method through simulation studies, a real data application, and theoretical calculation. We focus on cohort studies where a logistic disease model is appropriate and where group means can be treated as fixed effects. The results show a variety of advantages of the fully Bayesian approach and provide recommendations on situations where the traditional group-based exposure assessment method may not be suitable to use. PMID:23553785

Xing, Li; Burstyn, Igor; Richardson, David B; Gustafson, Paul

2013-09-20

198

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

PubMed Central

Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory (Helm-Estabrooks, 2002 for review). Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success (Freedman & Martin, 2001; Hula & McNeil, 2008; Ramsberger, 2005). In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. PMID:23127795

Vallila-Rohter, Sofia; Kiran, Swathi

2013-01-01

199

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

200

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

201

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

202

Anticipating the consequences of action: An fMRI study of intention-based task preparation  

PubMed Central

A key component of task preparation may be to anticipate the consequences of task-appropriate actions. This task switching study examined whether such type of “intentional” preparatory control relies on the presentation of explicit action effects. Preparatory BOLD activation in a condition with task-specific motion effect feedback was compared to identical task conditions with accuracy feedback only. Switch-related activation was found selectively in the effect feedback condition in the middle mid-frontal gyrus and in the anterior intraparietal sulcus. Consistent with research on attentional control, the posterior superior parietal lobule exhibited switch-related preparatory activation irrespective of feedback type. To conclude, preparatory control can occur via complementary attentional and intentional neural mechanisms depending on whether meaningful task-specific action effects lead to the formation of explicit effect representations. PMID:20477978

RUGE, HANNES; MÜLLER, SVEN C.; BRAVER, TODD S.

2011-01-01

203

Influence of mobile phone traffic on base station exposure of the general public.  

PubMed

The influence of mobile phone traffic on temporal radiofrequency exposure due to base stations during 7 d is compared for five different sites with Erlang data (representing average mobile phone traffic intensity during a period of time). The time periods of high exposure and high traffic during a day are compared and good agreement is obtained. The minimal required measurement periods to obtain accurate estimates for maximal and average long-period exposure (7 d) are determined. It is shown that these periods may be very long, indicating the necessity of new methodologies to estimate maximal and average exposure from short-period measurement data. Therefore, a new method to calculate the fields at a time instant from fields at another time instant using normalized Erlang values is proposed. This enables the estimation of maximal and average exposure during a week from short-period measurements using only Erlang data and avoids the necessity of long measurement times. PMID:20938233

Joseph, Wout; Verloock, Leen

2010-11-01

204

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

205

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

206

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

207

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

ERIC Educational Resources Information Center

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

Philp, Jenefer; Oliver, Rhonda; Mackey, Alison

2006-01-01

208

Agent-Based User and Task Modelling for Seamless Information Access via Personal Digital Assistants  

Microsoft Academic Search

The paper describes a case study of how a combination of techniques, such as agent technologies, user, task and context modeling can be used to adapt a distributed application for mobile users with Personal Digital Assistants (PDAs) and support seamless connection and access to a centralized information system in areas of disconnection. In a domain where users have typical tasks

GOLHA SHARIFI; RALPH DETERS; JULITA VASSILEVA

209

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

210

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

211

Discontinuous Model-Based Adaptive Control for Robots Executing Free and Constrained Tasks  

Microsoft Academic Search

We propose a robot controller for stably executing all phases of contact tasks involving discontinuities due to the introduction or removal of contact forces. Systems executing such tasks are characterized by ambiguous right hand sides in the differential equations of motion. Consequently, our approach develops upon ideas from generalized dynamical systems (GDSs), an orthogonalization principle, the Hertz contact model, and

Prasad Akella; Vicente Parra-vega; Suguru ArimotoO; Kazuo Tanie

1994-01-01

212

TASK-BASED MODULAR CONFIGURATIONS FOR HYBRID AND REDUNDANT PARALLEL ROBOTS  

Microsoft Academic Search

Parallel robots provide high stiffness, accelerations and accuracy. They are relatively complex products that are specialized to a specific task. Normally a new robot is designed for every new task. This paper shows an approach that makes it possible to configure parallel robots with the help of a modular system. Thence it is possible to reduce complexity costs and the

C. Stechert; H.-J. Franke; C. Wrege

213

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

214

Motivation and Performance within a Collaborative Computer-Based Modeling Task: Relations between Students' Achievement Goal Orientation, Self-Efficacy, Cognitive Processing, and Achievement  

ERIC Educational Resources Information Center

Purpose of the present study was to test a conceptual model of relations among achievement goal orientation, self-efficacy, cognitive processing, and achievement of students working within a particular collaborative task context. The task involved a collaborative computer-based modeling task. In order to test the model, group measures of…

Sins, Patrick H. M.; van Joolingen, Wouter R.; Savelsbergh, Elwin R.; van Hout-Wolters, Bernadette

2008-01-01

215

Development of a software based automatic exposure control system for use in image guided radiation therapy  

NASA Astrophysics Data System (ADS)

Modern image guided radiation therapy involves the use of an isocentrically mounted imaging system to take radiographs of a patient's position before the start of each treatment. Image guidance helps to minimize errors associated with a patients setup, but the radiation dose received by patients from imaging must be managed to ensure no additional risks. The Varian On-Board Imager (OBI) (Varian Medical Systems, Inc., Palo Alto, CA) does not have an automatic exposure control system and therefore requires exposure factors to be manually selected. Without patient specific exposure factors, images may become saturated and require multiple unnecessary exposures. A software based automatic exposure control system has been developed to predict optimal, patient specific exposure factors. The OBI system was modelled in terms of the x-ray tube output and detector response in order to calculate the level of detector saturation for any exposure situation. Digitally reconstructed radiographs are produced via ray-tracing through the patients' volumetric datasets that are acquired for treatment planning. The ray-trace determines the attenuation of the patient and subsequent x-ray spectra incident on the imaging detector. The resulting spectra are used in the detector response model to determine the exposure levels required to minimize detector saturation. Images calculated for various phantoms showed good agreement with the images that were acquired on the OBI. Overall, regions of detector saturation were accurately predicted and the detector response for non-saturated regions in images of an anthropomorphic phantom were calculated to generally be within 5 to 10 % of the measured values. Calculations were performed on patient data and found similar results as the phantom images, with the calculated images being able to determine detector saturation with close agreement to images that were acquired during treatment. Overall, it was shown that the system model and calculation method could potentially be used to predict patients' exposure factors before their treatment begins, thus preventing the need for multiple exposures.

Morton, Daniel R.

216

Sensor-Based, Task-Constrained Motion Generation Under Uncertainty Arne Sieverling Nicolas Kuhnen Oliver Brock1  

E-print Network

three obstacles with its onboard sensors: a rolling chair, a sign hanging from the ceiling, and a movingSensor-Based, Task-Constrained Motion Generation Under Uncertainty Arne Sieverling Nicolas Kuhnen environment cannot be known to the robot, and should do so only using their on-board sensors. We present

217

Presentation-Practice-Production and Task-Based Learning in the Light of Second Language Learning Theories.  

ERIC Educational Resources Information Center

Features of presentation-practice-production (PPP) and task-based learning (TBL) models for language teaching are discussed with reference to language learning theories. Pre-selection of target structures, use of controlled repetition, and explicit grammar instruction in a PPP lesson are given. Suggests TBL approaches afford greater learning…

Ritchie, Graeme

2003-01-01

218

Comparing the Outcomes of Online Listening versus Online Text-Based Tasks in University Level Italian L2 Study  

ERIC Educational Resources Information Center

In this paper, we describe an initial exploratory study designed to compare the outcomes of online listening and online text-based tasks in the context of the study of Italian at The University of Melbourne. Our findings allow us to characterise online listening and online reading as a qualitative difference between deep and surface approaches to…

Absalom, Matthew; Rizzi, Andrea

2008-01-01

219

"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

220

Visual Impairment: The Use of Visual Profiles in Evaluations of Icon Use in Computer-Based Tasks  

Microsoft Academic Search

This research investigates an empirical link between characteristics of impaired vision and user performance on computer-based systems. The underlying premise of this re- search is twofold: specific aspects of visual dysfunction can be linked to the task perfor- mance demonstrated by computer users with impaired vision, and graphical user in- terfaces can be modified to evoke enhanced performance from low-vision

Julie A. Jacko; Robert H. Rosa Jr.; Ingrid U. Scott; Charles J. Pappas; Max A. Dixon

2000-01-01

221

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

222

OpenVL: A Task-Based Abstraction for Developer-Friendly Computer Vision Gregor Miller and Sidney Fels  

E-print Network

OpenVL: A Task-Based Abstraction for Developer-Friendly Computer Vision Gregor Miller and Sidney,ssfels}@ece.ubc.ca Abstract Research into computer vision techniques has far out- paced the development of interfaces (such retaining sufficient power and flex- ibility to solve a wide variety of computer vision problems

British Columbia, University of

223

Genre-Based Tasks in Foreign Language Writing: Developing Writers' Genre Awareness, Linguistic Knowledge, and Writing Competence  

ERIC Educational Resources Information Center

This study examines how novice foreign language (FL) writers develop their genre awareness, linguistic knowledge, and writing competence in a genre-based writing course that incorporates email-writing tasks. To define genre, the study draws on systemic functional linguistics (SFL) that sees language as a resource for making meaning in a particular…

Yasuda, Sachiko

2011-01-01

224

Thinking Together: Exploring Aspects of Shared Thinking between Young Children during a Computer-Based Literacy Task  

ERIC Educational Resources Information Center

This study considers in what ways sustained shared thinking between young children aged 5-6 years can be facilitated by working in dyads on a computer-based literacy task. The study considers 107 observational records of 44 children from 6 different schools, in Oxfordshire in the UK, collected over the course of a school year. The study raises…

Wild, Mary

2011-01-01

225

Modelization and experimentation of conversational policies for non task oriented agents based on dissonance and relevance theories.  

E-print Network

to task oriented agents, in order to provide models for social science simulations. Dialogue between non for social informatics [8] because multi-agent based simulation for social issues is an increasing application domain of multi-agents re- search. Social issues deal with what we call ordinary people

Sansonnet, Jean-Paul

226

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

E-print Network

be expressed exactly. This analysis of the domain has the important (and rare) property of completeness, i.e., all possible abstract variations of the task are understood. This research presents efficiency results showing that a characterization for any given...

Mitra, Tanushree

2012-10-19

227

"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...

228

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

PubMed

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

2013-07-01

229

Prediction Task Assignment of Multi-UAV Approach Based on Consensus  

Microsoft Academic Search

\\u000a In the battlefield, UAV (Unmanned Aerial Vehicle) needs to assign tasks dynamically by using the radar tracking information,\\u000a but when the poor weather comes, or UAV enters blind area, the radar cannot gather the accurate information which severely\\u000a impair the assignment result. A new task assignment prediction method was proposed in this paper. We first predict the UAV\\u000a information using

Chen Chen; Zheng Qin; Jian-Kuan Xing

2010-01-01

230

Can time-based decay explain temporal distinctiveness effects in task switching?  

PubMed

In task switching, extending the response-cue interval (RCI) reduces the switch cost-the detriment to performance when switching compared to repeating tasks. This reduction has been used as evidence for the existence of task-set decay processes. Recently, this has been challenged by the observation of sequential dependencies on the RCI effect: switch cost is only reduced at longer RCIs when the previous trial had a short RCI. This trial-wise variation of RCI is thought to affect the temporal distinctiveness (TD) of a previous task's episodic trace, affecting the probability of its automatic retrieval on the current trial; importantly, TD is thought to be independent of the current trial's RCI. The present study highlights a dependency between the current RCI and TD, and demonstrates that a decay model can reproduce some patterns of data attributed to TD. Further, the decay account makes a strong prediction when TD is held constant: repetition response times should slow as the RCI increases, and switch response times should be facilitated. This prediction was tested via re-analysis of extant data and three experiments. The re-analysis provided some evidence for the decay account, but Experiments 1 and 2 report slowing for task repetition and switch trials, which cannot be explained by a task-set decay process. Experiment 3, which utilized tasks requiring perceptual judgements, showed small evidence for decay. We conclude that the data are largely consistent with the TD account and that the evidence for decay of higher-level task-sets is not convincing. PMID:25028178

Grange, James A; Cross, Ellen

2015-01-01

231

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

232

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

233

Evaluation of RF electromagnetic field exposure levels from cellular base stations in Korea.  

PubMed

This article presents the measurement results of human exposure to CDMA800 and CDMA1800 signals at locations in Korea where the general public has expressed concern. Measurements were performed at 50 locations across the country to compare the electromagnetic field levels with the general public exposure compliance limits. At each site, the distances between the nearest single or co-located base station and measurement positions were within a range of approximately 32-422 m. The measured exposure levels were very low compared with the international standard and the Korean human protection notice. The highest field level was 1.5 V/m, which corresponds to 0.15% of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human exposure. PMID:20564176

Kim, Byung Chan; Park, Seong-Ook

2010-09-01

234

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

PubMed Central

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

Horn, Simon; Barnard, Stephen; Rothkamm, Kai

2011-01-01

235

Response of Inconel 617 superalloy to combined ground-based and STS reentry exposure  

NASA Technical Reports Server (NTRS)

Inconel 617 is a nickel-based superalloy which is being considered for heat-shield applications because of its high-temperature strength, good oxidation resistance and high emittance of oxidized surfaces. While the effects of simulated reentry conditions on emittance and oxidation of Inconel 617 have been studied, the combined effects of the ground-based environment with sea salt exposure and the reentry environment have not been evaluated. Experimental results are presented to show the effects of environmental simulation including ground-based and reentry exposure on the emittance and oxidation of Inconel 617. Specimens were exposed to simulated reentry at a surface temperature of 2000 F in the Langley Research Center Hypersonic Materials Environmental Test System (HYMETS) Facility with and without alternate exposures to an atmospheric seashore environment or a laboratory sea salt environment. This paper presents emittance, mass loss, oxide chemistry, and alloy composition data for the specimens.

Clark, R. K.; Unnam, J.

1984-01-01

236

Task Oriented Behavior-Based State-Adaptive PID (Proportional Integral Derivative) Control for Low-Cost Mobile Robot  

Microsoft Academic Search

This paper describes how state-adaptive PID (Proportional Integral Derivative) control can be applied to a low-cost mobile robot. Behavior-based state-adaptive control for this mobile robot behaviors was designed using only three infrared sensors, a low-cost 8 bit microcontroller, and an electronic compass, with size of 22 cm ?? 21 cm ?? 16 cm. The task oriented behavior-based approach is implemented

Igi Ardiyanto

2010-01-01

237

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

238

Defining Participant Exposure Measures in Web-Based Health Behavior Change Programs  

PubMed Central

Background Published research on the use of Web-based behavior change programs is growing rapidly. One of the observations characterized as problematic in these studies is that participants often make relatively few website visits and spend only a brief time accessing the program. Properly structured websites permit the unobtrusive measurement of the ways in which participants access (are exposed to) program content. Research on participant exposure to Web-based programs is not merely of interest to technologists, but represents an important opportunity to better understand the broader theme of program engagement and to guide the development of more effective interventions. Objectives The current paper seeks to provide working definitions and describe initial patterns of various measures of participant exposure to ChewFree.com, a large randomized controlled trial of a Web-based program for smokeless tobacco cessation. Methods We examined measures of participant exposure to either an Enhanced condition Web-based program (interactive, tailored, and rich-media program) or a Basic condition control website (static, text-based material). Specific measures focused on email prompting, participant visits (number, duration, and pattern of use over time), and Web page viewing (number of views, types of pages viewed, and Web forum postings). Results Participants in the ChewFree.com Enhanced condition made more visits and spent more time accessing their assigned website than did participants assigned to the Basic condition website. In addition, exposure data demonstrated that Basic condition users thoroughly accessed program content, indicating that the condition provided a meaningful, face-valid control to the Enhanced condition. Conclusions We recommend that researchers conducting evaluations of Web-based interventions consider the collection and analysis of exposure measures in the broader context of program engagement in order to assess whether participants obtain sufficient exposure to relevant program content. PMID:16954125

Boles, Shawn M; Akers, Laura; Gordon, Judith S; Severson, Herbert H

2006-01-01

239

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

240

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

241

Beside the point: motor adaptation without feedback-based error correction in task-irrelevant conditions  

PubMed Central

Adaptation of movement may be driven by the difference between planned and actual motor performance, or the difference between expected and actual sensory consequences of movement. To identify how the nervous system differentially uses these signals, we asked: does motor adaptation occur when movement errors are irrelevant to the task goal? Participants reached on a digitizing tablet from a fixed start location to one of three targets: a point, an arc, or a ray. For the arc, reaches could be in any direction, but to a specific extent. For the ray, reaches could be to any distance, but in a targeted direction. After baseline reaching to the point, the direction or extent of continuous visual feedback was perturbed during training with either a cursor rotation or gain, respectively, while reaching to either the ray (goal = direction) or the arc (goal = extent). The perturbation, therefore, was either relevant or irrelevant to the task goal, depending on target type. During interspersed catch trials, the perturbation was removed and the target switched back to the point, identical to baseline. Although the goal of baseline and catch trials was the same, significant aftereffects in catch trials indicated behavioral adaptation in response to the perturbation. Adaptation occurred regardless of whether the perturbation was relevant to the task, and it was independent of feedback control. The presence of adaptation orthogonal to task demands supports the hypothesis that the nervous system can rely on sensory prediction to drive motor learning that can generalize across tasks. PMID:22157120

Schaefer, Sydney Y.; Shelly, Iris L.

2012-01-01

242

Beside the point: motor adaptation without feedback-based error correction in task-irrelevant conditions.  

PubMed

Adaptation of movement may be driven by the difference between planned and actual motor performance, or the difference between expected and actual sensory consequences of movement. To identify how the nervous system differentially uses these signals, we asked: does motor adaptation occur when movement errors are irrelevant to the task goal? Participants reached on a digitizing tablet from a fixed start location to one of three targets: a point, an arc, or a ray. For the arc, reaches could be in any direction, but to a specific extent. For the ray, reaches could be to any distance, but in a targeted direction. After baseline reaching to the point, the direction or extent of continuous visual feedback was perturbed during training with either a cursor rotation or gain, respectively, while reaching to either the ray (goal = direction) or the arc (goal = extent). The perturbation, therefore, was either relevant or irrelevant to the task goal, depending on target type. During interspersed catch trials, the perturbation was removed and the target switched back to the point, identical to baseline. Although the goal of baseline and catch trials was the same, significant aftereffects in catch trials indicated behavioral adaptation in response to the perturbation. Adaptation occurred regardless of whether the perturbation was relevant to the task, and it was independent of feedback control. The presence of adaptation orthogonal to task demands supports the hypothesis that the nervous system can rely on sensory prediction to drive motor learning that can generalize across tasks. PMID:22157120

Schaefer, Sydney Y; Shelly, Iris L; Thoroughman, Kurt A

2012-02-01

243

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

PubMed

Children with autism spectrum disorder (ASD) engage in highly perseverative and inflexible behaviours. Technological tools, such as robots, received increased attention as social reinforces and/or assisting tools for improving the performance of children with ASD. The aim of our study is to investigate the role of the robotic toy Keepon in a cognitive flexibility task performed by children with ASD and typically developing (TD) children. The number of participants included in this study is 81 children: 40 TD children and 41 children with ASD. Each participant had to go through two conditions: robot interaction and human interaction in which they had performed the reversal learning task. Our primary outcomes are the number of errors from acquisition phase and from reversal phase of the task; as secondary outcomes we have measured attentional engagement and positive affect. The results of this study showed that children with ASD are more engaged in the task and they seem to enjoy more the task when interacting with the robot compared with the interaction with the adult. On the other hand their cognitive flexibility performance is, in general, similar in the robot and the human conditions with the exception of the learning phase where the robot can interfere with the performance. Implication for future research and practice are discussed. PMID:25479815

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

2014-12-01

244

Assessment and comparison of total RF-EMF exposure in femtocell and macrocell base station scenarios.  

PubMed

The indoor coverage of a mobile service can be drastically improved by deployment of an indoor femtocell base station (FBS). However, the impact of its proximity on the total exposure of the human body to radio-frequency (RF) electromagnetic fields (EMFs) is unknown. Using a framework designed for the combination of near-field and far-field exposure, the authors assessed and compared the RF-EMF exposure of a mobile-phone (MP) user that is either connected to an FBS or a conventional macrocell base station while in an office environment. It is found that, in average macrocell coverage and MP use-time conditions and for Universal Mobile Telecommunications System technology, the total exposure can be reduced by a factor of 20-40 by using an FBS, mostly due to the significant decrease in the output power of the MP. In general, the framework presented in this study can be used for any exposure scenario, featuring any number of technologies, base stations and/or access points, users and duration. PMID:24185915

Aerts, Sam; Plets, David; Verloock, Leen; Martens, Luc; Joseph, Wout

2014-12-01

245

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

NASA Astrophysics Data System (ADS)

Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO instrumentation was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive op-tical instrument. SBO was requested to provide statistical information on the space debris population, in terms of number of objects and size distribution. The SBO was considered to be a cost-efficient instrumentation of 20 cm aperture and 6 deg field-of-view with flexible integration requirements. It should be possible to integrate the SBO easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. It was shown in the performance analysis that the statistical information on small-sized space debris can only be collected if the observation ranges are comparatively small. Two of the most promising concepts were to observe objects in LEO from a sensor placed into a sun-synchronous LEO, while objects in GEO should be observed from a GEO satellite. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are stud-ied for the build-up and to maintenance of a catalogue of objects. In this paper we analyse how the SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of objects at higher altitude, such as GEO and Medium-Earth Orbits (MEO). Of particular interest are the radiometric performance from which we derive the detectable object diameters, the coverage of a reference population, and the covered arc lengths of individual objects. The latter is of particular interest for the simu-lation of the orbit determination, correlation, and cataloguing. Assuming realistic noise levels known from the SBO design we simulate first orbit determination of unknown objects (surveys) and orbit improvements (tracking) for sample objects. We use a simulation environment that comprises the ESA Program for Radar and Optical Observation Forecasting (PROOF) in the version 2005 and AIUB's program system CelMech. ESA's MASTER-2005 serves as reference population for all analyses.

Flohrer, Tim; Krag, Holger; Klinkrad, Heiner; Schildknecht, Thomas

246

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

247

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.

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

2015-01-01

248

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

249

Exposure based waiving: the application of the toxicological threshold of concern (TTC) to inhalation exposure for aerosol ingredients in consumer products.  

PubMed

The inhalation toxicology studies available in the public domain have been reviewed to establish a database for inhalation toxicology and derive thresholds of toxicological concern (TTC) for effects in the respiratory tract and systemically for Cramer class 1 and 3 chemicals. These TTCs can be used as the basis for developing an exposure based waiving (EBW) approach to evaluating the potential for adverse effects from exposure to ingredients in aerosol products, used by consumers. The measurement of consumer exposure in simulated product use is key to the application of an exposure based waiving approach to evaluating potential consumer risk. The detailed exposure evaluation for aerosol ingredients with defined use scenarios, in conjunction with an evaluation of the potential structure activity relationship for toxicity and the TTCs for inhalation exposure could be used to waive undertaking inhalation toxicology studies under REACH. Not all classes of chemicals are suitable for such an approach, but for chemicals with a predictable low potential toxicity, and very low levels of exposure, this approach, could reduce the amount of inhalation toxicology studies required for the implementation of the European REACH legislation. Such an approach is consistent with the concept of developing 'intelligent testing strategies' for REACH. PMID:19275927

Carthew, P; Clapp, C; Gutsell, S

2009-06-01

250

Human Performance Task Batteries and Models: An Abilities-Based Directory. Final Report.  

ERIC Educational Resources Information Center

This directory represents the start of a research program directed towards the creation of a human abilities matrix which cross-references data on real world jobs, laboratory performance tasks, and human performance models. The matrix will use the "abilities requirements approach" as the unifying element among these three dimensions. The present…

Pond, Daniel J.; And Others

251

Virtual Reality-Based Navigation Task to Reveal Obstacle Avoidance Performance in Individuals With Visuospatial Neglect.  

PubMed

Background: Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentionalperceptual deficits caused by VSN or due to poststroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Methods: Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30° contralesionally/ ipsilesionally. Results: In the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. Conclusion: The observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentionalperceptual deficits due to VSN, independent of poststroke locomotor deficits, alters obstacle avoidance abilities. PMID:25420267

Aravind, Gayatri; Darekar, Anuja; Fung, Joyce; Lamontagne, Anouk

2014-11-20

252

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

253

Adaptive Task Flow Management of Distributed Spacecraft Bus based on Multi Agent Reinforcement Learning  

Microsoft Academic Search

Distributed systems have been intensively researched for large-scaled systems which require scalability in design phase and robustness in operation phase. In this paper, the concept of Distributed Spacecraft Bus (DSB) is proposed. Components of spacecraft bus are distributed to form a multi-agent system. In order to achieve high performance as well as fault tolerance, a novel method of adaptive task

Takashi Eishima; Shinichi Nakasuka

2005-01-01

254

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

255

A Task-based Architecture for Application-aware Robert Farrell  

E-print Network

, the administrator starts up the Notepad text editor and loads the autoexec.bat file. The task critic explains that autoexec.bat lists commands run at startup while he wants a file that lists configuration settings. Finally and the user continues his work. ARCHITECTURE Our proposed architectural framework (see Figure 1) supports

256

Humans and Monkeys Exert Metacognitive Control Based on Learning Difficulty in a Perceptual Categorization Task  

ERIC Educational Resources Information Center

Recently, Redford (2010) found that monkeys seemed to exert metacognitive control in a category-learning paradigm. Specifically, they selected more trials to view as the difficulty of the category-learning task increased. However, category-learning difficulty was determined by manipulating the family resemblance across the to-be-learned exemplars.…

Redford, Joshua S.

2010-01-01

257

Task-based optimization of modular robot configurations: minimized degree-of-freedom approach  

Microsoft Academic Search

A modular robot system consists of a collection of individual link and joint components that can be assembled into many different robot configurations. With fewer number of modules and degrees of freedom, a modular robot would have a simple configuration, high loading capacity, and low power consumption rate, so that it can perform the task effectively. In this article, the

Guilin Yang; I-Ming Chen

2000-01-01

258

A discussion of potential exposure metrics for use in epidemiological studies on human exposure to radiowaves from mobile phone base stations.  

PubMed

There is currently a high level of concern in many countries that exposure to radiowaves from mobile phone base stations may be hazardous to health. When investigating such suggested risks, epidemiologists need to define an exposure metric that can reliably discriminate between exposed and unexposed groups of people. We conducted a feasibility study to investigate if either short-term measurements of electric field strength, calculations of electric field strength, or distance from nearby mobile phone base stations could be used to develop a metric reflecting an individual's exposure to radiowaves. With electric field strengths in the range of 0.012-0.343 V/m, radiowaves from mobile phone base stations were found to give a material contribution to total exposure; however, stronger signals were frequently measured from other sources such as broadcast radio and television transmitters. Theoretical considerations and the measurements made during this work demonstrated that studies at the population level on suggested adverse effects of radiowaves from mobile phone base stations are not feasible since no valid metric for estimating historical exposures is currently available. The pace of radio infrastructure development is also such that today's measurements are unlikely to be good proxies for either past or future exposures. The complex propagation characteristics affecting the beams from base station antennas include shielding effects and multiple reflections from house walls and other buildings. These factors, combined with the presence of other environmental sources of radiowaves, cause distance from a base station to be a poor proxy for exposure to radiowaves indoors. It may be possible to adapt computer models developed by network providers to predict network coverage for epidemiological purposes; however, this has yet to be investigated. Furthermore, there is little evidence that presently justifies epidemiological studies being restricted to adverse effects of radiowaves from mobile phone base stations while neglecting radiowaves at other frequencies produced by different transmitters. PMID:11140443

Schüz, J; Mann, S

2000-01-01

259

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...

260

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

261

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

262

Non-Linear Normalized Entropy Based Exposure Blending Neil D.B. Bruce  

E-print Network

Non-Linear Normalized Entropy Based Exposure Blending Neil D.B. Bruce University of Manitoba innovations in the field of com- putational photography ranging from algorithmic efforts towards providing qualitative nature, those that provide realism while maximally preserving detail across e-mail: bruce

263

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

264

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...

265

Assessing the effects of sodium hypochlorite exposure on the characteristics of PVDF based membranes.  

PubMed

Sodium hypochlorite is commonly used as a cleaning agent to remove adsorbed foulants from PVDF based micro/ultra filtration membranes in water and wastewater treatment applications. Although effective for fouling control, extended sodium hypochlorite exposure can affect the physical/chemical characteristics and hinder the treatment performance of these membranes. To assess these effects, PVDF based membranes were exposed to sodium hypochlorite at different concentrations for varying periods of time, and the physical/chemical characteristics of the virgin and sodium hypochlorite exposed membranes were compared. The membranes were characterized based on chemical composition (FTIR and NMR), mechanical strength (yield strength), surface hydrophilicity (contact angle), pore size and porosity (scanning electron microscopy and challenge test), and membrane resistance (clean water permeation test). The results indicated that exposure dose and concentration of the sodium hypochlorite used have significant influence on the membrane characteristics. The impact of sodium hypochlorite exposure on the parameters investigated could be most accurately and consistently correlated to an exposure dose relationship of the form C(n)t (where, C = concentration and t = exposure time) rather than the Ct relationship commonly used to define the extent of exposure to cleaning agents. For all the parameters investigated, the power coefficient n was less than 1 indicating that time had a greater impact on the changes than did the concentration of the sodium hypochlorite. The results suggest that the use of sodium hypochlorite for chemical cleaning, at concentrations that are higher than those typically used for chemical cleaning would have less of an effect on the characteristics of the membrane materials. Changes in the characteristics were attributed to the oxidation of the hydrophilic additives (HA) present in blended PVDF membranes. PMID:23863391

Abdullah, Syed Z; Bérubé, Pierre R

2013-09-15

266

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

267

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

268

The Effectiveness of Classroom-Based Functional Analyses and Interventions for Off-Task and Disruptive Behaviors in a General Education Reading Classroom  

E-print Network

-task and disruptive behaviors were maintained by teacher attention. Based on these results, a function-based intervention was developed that included fixed momentary differential reinforcement of other behaviors (FM-DRO), differential reinforcement of alternative...

Shumate, Emily

2008-01-01

269

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

270

Exposure assessment in front of a multi-band base station antenna.  

PubMed

This study investigates occupational exposure to electromagnetic fields in front of a multi-band base station antenna for mobile communications at 900, 1800, and 2100?MHz. Finite-difference time-domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000?mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency--2100?MHz--results in the highest spatial-peak SAR averaged over 10?g of tissue, while the whole-body SAR is similar at all three frequencies. At distances > 200?mm from the antenna, the whole-body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial-peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial-peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands. PMID:21365667

Kos, Bor; Vali?, Blaž; Kotnik, Tadej; Gajšek, Peter

2011-04-01

271

Sinonasal Cancer and Occupational Exposure in a Population-Based Registry  

PubMed Central

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

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

2013-01-01

272

Characteristics of human arm based on musculoskeletal model in human-human cooperative task  

Microsoft Academic Search

Human characteristics are supposed to be applied to the control systems of the human-friendly robots. Therefore, it is important to know the human characteristics in human-robot cooperative tasks. In this study, we considered a single rotational degree of freedom experimental system as well as a mass-spring-damper-friction dynamic model for the human arm and analyzed the master-slave and the master-semi master

Nan Zhang; Ryojun Ikeura; Yuanxin Wang; Kazuki Mizutani; Hideki Sawai

2007-01-01

273

Robot Skill Transfer Based on B-Spline Fuzzy Controllers for Force-Control Tasks  

Microsoft Academic Search

Human-beings can easily describe their behaviour by IF-THEN rules, which can be transferred from one task to another with slight local changes. However, standard tech- niques for function approximation like neuronal networks or associative memories are unable to work with rules. We introduce a method for extracting and importing human readable rules from and to a B-spline fuzzy controller. Rule

Markus Ferch; Jianwei Zhang; Alois Knoll

1999-01-01

274

The sensitivity of a palm-based psychomotor vigilance task to severe sleep loss  

Microsoft Academic Search

In this study, we evaluated the sensitivity of a 5-min personal digital assistant—psychomotor vigilance test (PDA-PVT) to\\u000a severe sleep loss. Twenty-one participants completed a 10-min PVT-192 and a 5-min PDA—PVT at two hourly intervals during 62\\u000a h of sustained wakefulness. For both tasks, response speed and number of lapses (RTs > 500) per minute significantly increased\\u000a with increasing hours of

Nicole Lamond; Sarah M. Jay; Jillian Dorrian; Sally A. Ferguson; Gregory D. Roach; Drew Dawson

2008-01-01

275

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

276

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

PubMed Central

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

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

2014-01-01

277

Effect of Exposure to an Authentic Pedagogical Task on Student Academic Performance, Student Perceptions of Pedagogical Authenticity and Higher Order Thinking  

ERIC Educational Resources Information Center

The purpose of this study was to examine the effect of an authentic pedagogical (AP) task on measurements of student academic performance, student perceptions of pedagogical authenticity, and higher order thinking in undergraduate psychology courses. In this quasi-experimental design, comprehensive final exam scores, student ratings on the…

Killen, Marlin

2012-01-01

278

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

279

Benzene and total hydrocarbons exposures in the downstream petroleum industries.  

PubMed

A review of studies, including both articles published in peer-reviewed journals and reports that were not peer reviewed, regarding occupational exposure to benzene and total hydrocarbons in the downstream petroleum industry operations was performed. The objective was to provide a broad estimate of exposures by compiling exposure data according to the following categories: refinery, pipeline, marine, rail, bulk terminals and trucks, service stations, underground storage tanks, tank cleaning, and site remediations. The data in each category was divided into personal occupational long-term and short-term samples. The summarized data offers valuable assistance to hygienists by providing them with an estimate and range of exposures. The traditional 8-hour time-weighted average (TWA) exposure and the 40-hour workweek do not generally coincide with exposure periods applicable to workers in marine, pipeline, railcar, and trucking operations. They are more comparable with short-term exposure or task-based exposure assessments. The marine sector has a large number of high exposures. Although relatively few workers are exposed, their exposures to benzene and total hydrocarbons are sometimes an order of magnitude higher than the respective exposure limits. It is recommended that in the future, it would be preferable to do more task-based exposure assessments and fewer traditional TWA long-term exposure assessments within the various sectors of the downstream petroleum industry. PMID:11331990

Verma, D K; Johnson, D M; Shaw, M L; des Tombe, K

2001-01-01

280

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

ERIC Educational Resources Information Center

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

Li, Jinrong

2012-01-01

281

The Development and Implementation of a Web-Based Formative Peer Assessment System for Enhancing Students' Metacognitive Awareness and Performance in Ill-Structured Tasks  

ERIC Educational Resources Information Center

An assessment was conducted of a web-based formative peer assessment system (WFPAS) emphasizing learners' metacognitive awareness for their performance in ill-structured tasks. Results indicate that the WFPAS group achieved significantly higher scores for metacognitive awareness and performance in ill-structured tasks than the traditional…

Kim, Minjeong; Ryu, Jeeheon

2013-01-01

282

CRADA Final Report: Materials Development For Pulp and Paper Mills, Task 9 Proof of Commercial Concept: Commodity Carbon Fibers From Weyerhaeuser Lignin Based Fibers  

Microsoft Academic Search

Tasks were assigned to Oak Ridge National Laboratory (ORNL) researchers for the development of lignin-based carbon fiber from a specific precursor that was produced by the Participant (Weyerhaeuser Corporation). These tasks included characterization of precursor polymers and fibers; and the development of conversion parameters for the fibers. ORNL researchers provided recommendations for in-house characterization of the precursor at the participant's

Felix L Paulauskas; Amit K Naskar; Soydan Ozcan; James R Keiser; John Peter Gorog

2010-01-01

283

Grid Task Execution  

NASA Technical Reports Server (NTRS)

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

Hu, Chaumin

2007-01-01

284

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

PubMed Central

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

Wieslander, G; Norbäck, D; Edling, C

1994-01-01

285

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

SciTech Connect

A job task analysis was performed to determine the major tasks and specific competencies required of electric power company customer engineers in a changing economic and technological climate. Through an examination of occupational documents, interviews with occupational specialists, and a questionnaire completed by an electric utility company focus group, 13 major customer tasks and 222 specific competencies were identified. Based on the data, guidelines for a consultative sales training curriculum were recommended. While three of the 222 customer engineer competencies were unconfirmed, this study does represent the single source of at least 219 verified electric utility customer-engineer competencies, heretofore not in existence. Formal training of electric utility customer engineers should include a thorough orientation to the many specific terms, requirements, practices, rules, and procedures of the electric utility industry and company, and this training should include on the job coaching with followup instruction. The formal training should be consistent with the consultative selling style and philosophy to meet changing needs of customers as well as the electric utility industry and its representatives.

Schmidt, D.C.

1985-01-01

286

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

287

Diagnostic Ionizing Radiation Exposure in a Population-Based Cohort of Patients with Inflammatory Bowel Disease  

Microsoft Academic Search

OBJECTIVE:For diagnosis, assessing disease activity, complications and extraintestinal manifestations, and monitoring response to therapy, patients with inflammatory bowel disease undergo many radiological studies employing ionizing radiation. However, the extent of radiation exposure in these patients is unknown.METHODS:A population-based inception cohort of 215 patients with inflammatory bowel disease from Olmsted County, Minnesota, diagnosed between 1990 and 2001, was identified. The total

Joanna M. Peloquin; Darrell S. Pardi; William J. Sandborn; Joel G. Fletcher; Cynthia H. McCollough; Beth A. Schueler; James A. Kofler; Felicity T. B. Enders; Sara J. Achenbach

2008-01-01

288

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

Microsoft Academic Search

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

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

2008-01-01

289

T Cell-Based Tracking of Multidrug Resistant Tuberculosis Infection after Brief Exposure  

Microsoft Academic Search

Molecular epidemiology indicates significant transmission of Myco- bacterium tuberculosis after casual contact with infectious tuberculo- sis cases. We investigated M. tuberculosis transmission after brief exposure using a T cell-based assay, the enzyme-linked-immunospot (ELISPOT) for IFN-. After childbirth, a mother was diagnosed with sputum smear-positive multidrug-resistant tuberculosis. Forty-one neonates and 47 adults were present during her admission on the maternity unit;

Luca Richeldi; Katie Ewer; Monica Losi; Barbara M. Bergamini; Pietro Roversi; Jonathan Deeks; Leonardo M. Fabbri; Ajit Lalvani

2004-01-01

290

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

291

Development of a Fluorescence-Based Sensor for Rapid Diagnosis of Cyanide Exposure  

PubMed Central

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

2015-01-01

292

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

SciTech Connect

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

Ho, Clifford Kuofei

2004-06-01

293

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

294

Student Off-Task Behavior in Computer-Based Learning in the Philippines: Comparison to Prior Research in the USA  

ERIC Educational Resources Information Center

Background: Off-task behavior can be defined as any behavior that does not involve the learning task or material, or where learning from the material is not the primary goal. One suggested path for understanding how to address off-task behavior is to study classrooms where off-task behavior is less common, particularly in Asia, in order to…

Rodrigo, Ma. Mercedes T.; Baker, Ryan S. J. D.; Rossi, Lisa

2013-01-01

295

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

ERIC Educational Resources Information Center

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

Brookhart, Donna; McGuire, Pat

296

Characteristics of human arm based on musculoskeletal model in human-human cooperative task  

NASA Astrophysics Data System (ADS)

Human characteristics are supposed to be applied to the control systems of the human-friendly robots. Therefore, it is important to know the human characteristics in human-robot cooperative tasks. In this study, we considered a single rotational degree of freedom experimental system as well as a mass-spring-damper-friction dynamic model for the human arm and analyzed the master-slave and the master-semi master cooperative motions. Through the master-slave cooperative motion, we verified the application of the mass-spring-friction dynamic model of the slave's arm, and regarding its parameter we found the damping factor as zero and the stiffness as well as the coulomb friction torque almost individually invariable. Through the master-semi master cooperative motion, we got the torque characteristics and drew a comparison of them with those in the master-slave cooperative motion, and then we found improved torque characteristics, the constant torque characteristics.

Zhang, Nan; Ikeura, Ryojun; Wang, Yuanxin; Mizutani, Kazuki; Sawai, Hideki

2007-12-01

297

Template-based approach for detecting motor task activation-related hyperperfusion in pulsed ASL data.  

PubMed

Arterial spin labeling (ASL) permits the noninvasive measurement of quantitative values of cerebral blood flow (CBF) and is thus well adapted to study inter- and intrasubject perfusion variations whether at rest or during an fMRI task. In this study, a template approach to detect brain activation as a CBF difference between resting and activated groups was compared with a standard generalized linear model (GLM) analysis. A basal perfusion template of PICORE-Q2TIPS ASL images acquired at 3T from a group of 25 healthy subjects (mean age 31.6 ± 8.3 years) was created. The second group of 12 healthy subjects (mean age 28.6 ± 2.7 years) performed a block-design motor task. The template was compared with the mean activated image of the second group both at the individual and at the group level to extract activation maps. The results obtained using a GLM analysis of the whole sequence was used as ground truth for comparison. The influences of spatial normalization using DARTEL registration and of correction of partial volume effects (PVE) in the construction of the template were assessed. Results showed that a basal perfusion template can detect activation-related hyperperfusion in motor areas. The true positive ratio was increased by 2.5% using PVE-correction and by 3.2% using PVE-correction with DARTEL registration. On average, the group comparison presented a 2.2% higher true positive ratio than the one-to-many comparison. PMID:23408457

Petr, Jan; Ferré, Jean-Christophe; Raoult, Hélène; Bannier, Elise; Gauvrit, Jean-Yves; Barillot, Christian

2014-04-01

298

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

299

Comparison between effective doses for voxel-based and stylized exposure models from photon and electron irradiation  

NASA Astrophysics Data System (ADS)

For the last two decades, the organ and tissue equivalent dose as well as effective dose conversion coefficients recommended by the International Commission on Radiological Protection (ICRP) have been determined with exposure models based on stylized MIRD5-type phantoms representing the human body with its radiosensitive organs and tissues according to the ICRP Reference Man released in Publication No. 23, on Monte Carlo codes sometimes simulating rather simplified radiation physics and on tissue compositions from different sources. Meanwhile the International Commission on Radiation Units and Measurements (ICRU) has published reference data for human tissue compositions in Publication No. 44, and the ICRP has released a new report on anatomical reference data in Publication No. 89. As a consequence many of the components of the traditional stylized exposure models used to determine the effective dose in the past have to be replaced: Monte Carlo codes, human phantoms and tissue compositions. This paper presents results of comprehensive investigations on the dosimetric consequences to be expected from the replacement of the traditional stylized exposure models by the voxel-based exposure models. Calculations have been performed with the EGS4 Monte Carlo code for external and internal exposures to photons and electrons with the stylized, gender-specific MIRD5-type phantoms ADAM and EVA on the one hand and with the recently developed tomographic or voxel-based phantoms MAX and FAX on the other hand for a variety of exposure conditions. Ratios of effective doses for the voxel-based and the stylized exposure models will be presented for external and internal exposures to photons and electrons as a function of the energy and the geometry of the radiation field. The data indicate that for the exposure conditions considered in these investigations the effective dose may change between +60% and -50% after the replacement of the traditional exposure models by the voxel-based exposure models.

Kramer, R.; Khoury, H. J.; Vieira, J. W.

2005-11-01

300

The Effect of Prenatal Drug Exposure and Caregiving Context on Children’s Performance on a Task of Sustained Visual Attention  

Microsoft Academic Search

Objectives: Three groups of children from low-income, urban environments were examined to determine the effects of prenatal drug exposure (PDE) and caregiving environment on sustained visual attention (SVA) at 7 years of age. Methods: Drug-exposed children remaining in maternal care (n 43), drug-exposed children placed in nonmaternal care (n 45), and community comparison (CC) children (n 56) were admin- istered

John P. Ackerman; Antolin M. Llorente; Maureen M. Black; Claire S. Ackerman; Lacy A. Mayes; Prasanna Nair

2008-01-01

301

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

302

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

303

Occupational exposure to base stations-compliance with EU directive 2004/40/EC.  

PubMed

The rapid growth of mobile communications has not only led to a rising number of mobile telephones. It has also made base stations essential for these services widespread on many roofs. However, not everyone is aware that working close to sources of high frequency electromagnetic fields (EMF), such as transmitter antennas for mobile phones, pagers and police, fire and other emergency services, can result in high EMF exposure. This paper deals with measurements and calculations of the compliance boundary for workers in one typical roof top base station setting according to EU Directive and other relevant EN standards. PMID:16790176

Gajsek, Peter; Simuni?, Dina

2006-01-01

304

Assessment of cortical response during motor task in adults by a multimodality approach based on fNIRS-EEG, fMRI-EEG, and TMS  

NASA Astrophysics Data System (ADS)

A multimodality approach based on fNIRS-EEG, fMRI-EEG and TMS was used on adult volunteers during motor task aiming at optimizing a functional imaging procedure to be eventually used on patients with movement disorders.

Torricelli, Alessandro; Contini, Davide; Caffini, Matteo; Zucchelli, Lucia; Cubeddu, Rinaldo; Spinelli, Lorenzo; Molteni, Erika; Bianchi, Anna Maria; Baselli, Giuseppe; Cerutti, Sergio; Visani, Elisa; Gilioli, Isabella; Rossi Sebastiano, Davide; Schiaffi, Elena; Panzica, Ferruccio; Franceschetti, Silvana

2011-07-01

305

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

PubMed Central

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

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

2013-01-01

306

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

307

A New Human Perception-Based Over-Exposure Detection Method for Color Images  

PubMed Central

To correct an over-exposure within an image, the over-exposed region (OER) must first be detected. Detecting the OER accurately has a significant effect on the performance of the over-exposure correction. However, the results of conventional OER detection methods, which generally use the brightness and color information of each pixel, often deviate from the actual OER perceived by the human eye. To overcome this problem, in this paper, we propose a novel method for detecting the perceived OER more accurately. Based on the observation that recognizing the OER in an image is dependent on the saturation sensitivity of the human visual system (HVS), we detect the OER by thresholding the saturation value of each pixel. Here, a function of the proposed method, which is designed based on the results of a subjective evaluation on the saturation sensitivity of the HVS, adaptively determines the saturation threshold value using the color and the perceived brightness of each pixel. Experimental results demonstrate that the proposed method accurately detects the perceived OER, and furthermore, the over-exposure correction can be improved by adopting the proposed OER detection method. PMID:25225876

Yoon, Yeo-Jin; Byun, Keun-Yung; Lee, Dae-Hong; Jung, Seung-Won; Ko, Sung-Jea

2014-01-01

308

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

309

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

PubMed Central

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

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

2007-01-01

310

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

311

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

312

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

313

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

PubMed Central

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

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

2013-01-01

314

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

315

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

PubMed Central

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

Cui, Kai; Zhou, Kuanjiu; Yu, Yanshuo

2014-01-01

316

A task-based evaluation method for x-ray breast imaging systems using variable-background phantoms  

NASA Astrophysics Data System (ADS)

For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as breast tomosynthesis and computed tomography, has drawn much attention from the medical imaging community, either academia or industry. However, the trade offs between patient safety and the efficacy of the devices have yet to be investigated with use of objective performance metrics. Moreover, as the 3D imaging systems give depth information that was not available in planar mammography, standard mammography quality assurance and control (QA/QC) phantoms used for measuring system performance are not appropriate since they do not account for background variability and clinically relevant tasks. Therefore, it is critical to develop QA/QC methods that incorporate background variability with use of a task-based statistical assessment methodology.1 In this work, we develop a physical phantom that simulates variable backgrounds using spheres of different sizes and densities, and present an evaluation method based on statistical decision theory,2 in particular, with use of the ideal linear observer, for evaluating planar and 3D x-ray breast imaging systems. We demonstrate our method for a mammography system and compare the variable phantom case to that of a phantom of the same dimensions filled with water. Preliminary results show that measuring the system's detection performance without consideration of background variability may lead to misrepresentation of system performance.

Park, Subok; Liu, Haimo; Jennings, Robert; Leimbach, Robert; Kyprianou, Iacovos; Badano, Aldo; Myers, Kyle

2009-02-01

317

Yoga training and motor speed based on a finger tapping task.  

PubMed

A finger tapping task was used to assess motor speed (MS) of both hands in 53 adults and 152 children before and after yoga training and in 38 adults of a non-yoga (control) group. All subjects were right hand dominant. The 30-second tapping speed (TS) test was considered as three time intervals, i.e. 0-10 second (TS1), 10-20 seconds (TS2) and 20-30 seconds (TS3). There was a significant (Student's t-test) increase in all three TS values following 10 days of yoga in children and 30 days of yoga in adults. However for both groups at baseline and final assessments, TS2 and TS3 were significantly lower than TS1. Hence the TS was increased after yoga training during the first 10-seconds of the test but not during the next 20 seconds. These results suggest an increase in motor speed for repetitive finger movements following yoga training, but not in strength or endurance, as the increase was not sustained over 30 sec. PMID:10776461

Dash, M; Telles, S

1999-10-01

318

Visual search behaviours and verbal reports during film-based and in situ representative tasks in volleyball.  

PubMed

Several researchers have explored the processes underlying perceptual-cognitive expertise, mainly using film-based studies. However, few have compared the extent to which data from film-based settings differ from those obtained through in situ collection. This gap in the literature is a relevant concern, since scientific research is used to provide guidance for designing training programmes. In this paper, eye movement recording and verbal reports of thinking were combined to explore the processes underpinning skilled performance in a representative volleyball task involving both film-based and in situ data collection. Nine volleyball players performed as backcourt defenders while wearing an eye-tracking device and providing verbal reports of thinking after each sequence. A number of significant differences were observed between the data gathered under film-based and in situ conditions. Namely, in the in situ condition participants employed longer fixations (728.11 ± 129.27 ms) than in the film condition (659.57 ± 178.06 ms), and there were differences in the nature of the fixation locations. With respect to verbal reports, participants exhibited superior level of sophistication in the in situ condition (2.57 ± 0.50 vs. 2.30 ± 0.84 in the film condition), while denoting a greater concern with the opponents under this condition (1.00 ± 0.73) than in the film condition (0.59 ± 0.60). These differences emerged despite task design and constraints being highly similar. No differences were apparent in the number of gaze fixations and fixation locations across conditions or in the number of verbalised condition concepts. Although exploratory, our data suggest that the mechanisms underpinning skilled decision-making in sports differ between film-based and in situ conditions. PMID:24533524

Afonso, José; Garganta, Júlio; McRobert, Allistair; Williams, Mark; Mesquita, Isabel

2014-01-01

319

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

PubMed

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

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

2005-01-01

320

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

321

Attentional spreading to task-irrelevant object features: experimental support and a 3-step model of attention for object-based selection and feature-based processing modulation  

PubMed Central

Directing attention to a specific feature of an object has been linked to different forms of attentional modulation. Object-based attention theory founds on the finding that even task-irrelevant features at the selected object are subject to attentional modulation, while feature-based attention theory proposes a global processing benefit for the selected feature even at other objects. Most studies investigated either the one or the other form of attention, leaving open the possibility that both object- and feature-specific attentional effects do occur at the same time and may just represent two sides of a single attention system. We here investigate this issue by testing attentional spreading within and across objects, using reaction time (RT) measurements to changes of attended and unattended features on both attended and unattended objects. We asked subjects to report color and speed changes occurring on one of two overlapping random dot patterns (RDPs), presented at the center of gaze. The key property of the stimulation was that only one of the features (e.g., motion direction) was unique for each object, whereas the other feature (e.g., color) was shared by both. The results of two experiments show that co-selection of unattended features even occurs when those features have no means for selecting the object. At the same time, they demonstrate that this processing benefit is not restricted to the selected object but spreads to the task-irrelevant one. We conceptualize these findings by a 3-step model of attention that assumes a task-dependent top-down gain, object-specific feature selection based on task- and binding characteristics, and a global feature-specific processing enhancement. The model allows for the unification of a vast amount of experimental results into a single model, and makes various experimentally testable predictions for the interaction of object- and feature-specific processes. PMID:24959132

Wegener, Detlef; Galashan, Fingal Orlando; Aurich, Maike Kathrin; Kreiter, Andreas Kurt

2014-01-01

322

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

323

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

324

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

325

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

326

Functional relationships between the hippocampus and dorsomedial striatum in learning a visual scene-based memory task in rats.  

PubMed

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

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

2014-11-19

327

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...

328

A Systemic Exposure-Based Alternative to the Maximum Tolerated Dose for Carcinogenicity Studies of Human Therapeutics  

Microsoft Academic Search

A systemic exposure-based alternative to the maximum tolerated dose (MTD) for high-dose selection in carcinogenicity studies for human therapeutics was accepted at the Second International Conference on Harmonization (ICH-2). The systemic exposure-based alternative to the MTD is suitable for nongenotoxic compounds with low rodent toxicity that are metabolized similarly in rodents and humans. This is the first product of an

Joseph F. Contrera; Abigail C. Jacobs; Hullahalli R. Prasanna; Mehul Mehta; Wendelyn J. Schmidt; Joseph De. George

1995-01-01

329

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

330

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

331

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

332

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

333

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

PubMed

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

334

Decomposing decision components in the stop-signal task: a model-based approach to individual differences in inhibitory control.  

PubMed

The stop-signal task, in which participants must inhibit prepotent responses, has been used to identify neural systems that vary with individual differences in inhibitory control. To explore how these differences relate to other aspects of decision making, a drift-diffusion model of simple decisions was fitted to stop-signal task data from go trials to extract measures of caution, motor execution time, and stimulus processing speed for each of 123 participants. These values were used to probe fMRI data to explore individual differences in neural activation. Faster processing of the go stimulus correlated with greater activation in the right frontal pole for both go and stop trials. On stop trials, stimulus processing speed also correlated with regions implicated in inhibitory control, including the right inferior frontal gyrus, medial frontal gyrus, and BG. Individual differences in motor execution time correlated with activation of the right parietal cortex. These findings suggest a robust relationship between the speed of stimulus processing and inhibitory processing at the neural level. This model-based approach provides novel insight into the interrelationships among decision components involved in inhibitory control and raises interesting questions about strategic adjustments in performance and inhibitory deficits associated with psychopathology. PMID:24405185

White, Corey N; Congdon, Eliza; Mumford, Jeanette A; Karlsgodt, Katherine H; Sabb, Fred W; Freimer, Nelson B; London, Edythe D; Cannon, Tyrone D; Bilder, Robert M; Poldrack, Russell A

2014-08-01

335

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

336

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

337

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

338

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

339

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

340

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

341

Schema Theory-Based Pre-Reading Tasks: A Neglected Essential in the ESL Reading Class.  

ERIC Educational Resources Information Center

Describes a study in which an English-as-a-Second-Language reading instructor worked with a group of intermediate students that focused on schema theory-based pre-reading activities. Highlights the students' impressions on the strategies covered during the term. (Author/VWL)

Ajideh, Parviz

2003-01-01

342

Cluster Structure and Localization of Brain Functional Networks Based on the ERP Signals of Auditory Task  

Microsoft Academic Search

The brain functional networks derived from multi-channel ERP signals are analyzed based on the phase synchronization theory. The nodes of brain functional networks are represented by the channels of ERP signals, and the connectivity of brain functional networks is described by the interaction among the channels. The edge between two different channels exists only if the phase coupling index is

Zhao Zhuo; Shi-Min Cai; Zhong-Qian Fu; Pei-Ling Zhou

2010-01-01

343

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

344

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

345

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

346

Integrated planning of robotic and computer vision based spatial reasoning tasks  

Microsoft Academic Search

This paper describes research that is designed to integrate computer vision with complex robot planning in order to achieve a system capable of autonomously reasoning in spatially reconfigurable environments. In its basic form, the computer vision based spatial reasoning system provides the capability to view objects of known structure and kinematic design and to reason about their spatial locations and

Michael Mageetl; William Hoffy; Lance GatrellY; Martin Marietta; William J. Wolfe

1990-01-01

347

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

ERIC Educational Resources Information Center

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…

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-01-01

348

Web-Based Learning: How Task Scaffolding and Web Site Design Support Knowledge Acquisition  

ERIC Educational Resources Information Center

Using WebQuests for inquiry-based learning represents a higher-order use of technology requiring students to exercise information seeking, analyzing, and synthesizing strategies. This research was designed to obtain a better understanding of how to enhance the pedagogical effectiveness of WebQuests and of how students interact with the various…

MacGregor, S. Kim; Lou, Yiping

2005-01-01

349

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

350

LEARNING COMPLEX DOMAINS AND COMPLEX TASKS, THE PROMISE OF SIMULATION BASED TRAINING  

E-print Network

projects (SIMQUEST and Co-Lab1 ) in which simulation based learning environments in engineering and science be made of data appearing therein. For project details see the project websites: www.simquest.nl, and www.co-lab, we can say that the new view on learning entails that learners are encouraged to construct their own

Paris-Sud XI, Université de

351

Comparative Analysis for the Inverse Kinematics of Redundant Manipulators based on Repetitive Tracking Tasks  

E-print Network

Comparative Analysis for the Inverse Kinematics of Redundant Manipulators based on Repetitive(DoF) of open loop kinematic chain, the closed-loop inverse kinematics algorithm(CLIK) via pseudoinverse method. The repetitive trajectories are tracked in the simulations made on the 3-DoF planar and 4-DoF spatial

Li, Yangmin

352

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

353

Domestic Radon Exposure and Risk of Childhood Cancer: A Prospective Census-Based Cohort Study  

PubMed Central

Background: In contrast with established evidence linking high doses of ionizing radiation with childhood cancer, research on low-dose ionizing radiation and childhood cancer has produced inconsistent results. Objective: We investigated the association between domestic radon exposure and childhood cancers, particularly leukemia and central nervous system (CNS) tumors. Methods: We conducted a nationwide census-based cohort study including all children < 16 years of age living in Switzerland on 5 December 2000, the date of the 2000 census. Follow-up lasted until the date of diagnosis, death, emigration, a child’s 16th birthday, or 31 December 2008. Domestic radon levels were estimated for each individual home address using a model developed and validated based on approximately 45,000 measurements taken throughout Switzerland. Data were analyzed with Cox proportional hazard models adjusted for child age, child sex, birth order, parents’ socioeconomic status, environmental gamma radiation, and period effects. Results: In total, 997 childhood cancer cases were included in the study. Compared with children exposed to a radon concentration below the median (< 77.7 Bq/m3), adjusted hazard ratios for children with exposure ? the 90th percentile (? 139.9 Bq/m3) were 0.93 (95% CI: 0.74, 1.16) for all cancers, 0.95 (95% CI: 0.63, 1.43) for all leukemias, 0.90 (95% CI: 0.56, 1.43) for acute lymphoblastic leukemia, and 1.05 (95% CI: 0.68, 1.61) for CNS tumors. Conclusions: We did not find evidence that domestic radon exposure is associated with childhood cancer, despite relatively high radon levels in Switzerland. Citation: Hauri D, Spycher B, Huss A, Zimmermann F, Grotzer M, von der Weid N, Weber D, Spoerri A, Kuehni C, Röösli M, for the Swiss National Cohort and the Swiss Paediatric Oncology Group (SPOG). 2013. Domestic radon exposure and risk of childhood cancer: a prospective census-based cohort study. Environ Health Perspect 121:1239–1244;?http://dx.doi.org/10.1289/ehp.1306500 PMID:23942326

Hauri, Dimitri; Spycher, Ben; Huss, Anke; Zimmermann, Frank; Grotzer, Michael; von der Weid, Nicolas; Weber, Damien; Spoerri, Adrian; Kuehni, Claudia E.

2013-01-01

354

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

PubMed Central

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

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

2015-01-01

355

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

356

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

357

A web-based route planning tool to reduce cyclists' exposures to traffic pollution: a case study in Montreal, Canada.  

PubMed

We developed a web-based route planning tool for cyclists in Montreal, Canada, using spatial monitoring data for ambient nitrogen dioxide (NO2). With this tool, we estimated exposures to NO2 along shortest routes and lower exposure alternatives using origin-destination survey data. On average, exposures were estimated to be lower by 0.76 ppb (95% CI: 0.72, 0.80) relative to the shortest route, with decreases of up to 6.1 ppb for a single trip. Cumulative exposure levels (ppb km) decreased by approximately 4%. In general, the benefits of decreased exposure could be achieved with little increase (less than 1 km) in the overall route length. PMID:23562391

Hatzopoulou, Marianne; Weichenthal, Scott; Barreau, Guillaume; Goldberg, Mark; Farrell, William; Crouse, Dan; Ross, Nancy

2013-05-01

358

Investigating the use of ICT-based concept mapping techniques on creativity in literacy tasks  

Microsoft Academic Search

The key research question in this small-scale study focuses on the effects that an ICT (in- formation and communications technologies)-based concept mapping intervention has on creativity and writing achievement in 10-11-year-old primary age pupils. The data shows that pupils using a concept mapping intervention significantly improve their NFER non- verbal reasoning age-standardised scores over a control group with a higher

Nigel R. Riley; Mauri Åhlberg

2004-01-01

359

The Design and Evaluation of Task Assignment Algorithms for GWAP-based Geospatial Tagging Systems  

Microsoft Academic Search

Geospatial tagging (geotagging) is an emerging and very promising application that can help users find a wide variety of location-specific\\u000a information, and thereby facilitate the development of advanced location-based services. Conventional geotagging systems share\\u000a some limitations, such as the use of a two-phase operating model and the tendency to tag popular objects with simple contexts.\\u000a To address these problems, a

Ling-Jyh Chen; Yu-Song Syu; Hung-Chia Chen; Wang-Chien Lee

360

Pixel arrangement design of retina-like sensor based on forward motion imaging visual task  

NASA Astrophysics Data System (ADS)

Retina-like sensor is a kind of anthropomorphic visual sensor, which mimic the distribution of photoreceptors in the human retina. They are applied in fields of machine vision and target tracking. However, there are few reports on retina-like sensor used for forward-motion imaging. During forward-motion imaging, as the objects being imaged move along the optical axis direction during the integration time, image quality becomes worse towards the border of the image. In order to get clearer image, retina-like sensor are trying to be designed based on the feature of forward-motion imaging. In this paper, firstly, the degraded law of rectilinear sensor used for forward-motion imaging is analyzed, the retina-like sensor model based on the feature of forward-motion imaging are proposed. Secondly, the output image of retina-like sensor and rectilinear sensor used during the forward-motion imaging for different scenes at different degeneration degrees are simulated, respectively. Thirdly, the simulated images of both two sensors are assessed by four different image quality assessment methods including visual information fidelity (VIF), complex wavelet structural similarity index (CW-SSIM), Gabor filtered image contrast similarity (GFCS) and peak signal to noise ratio (PSNR), besides, the data amount of two sensors are compared. Four image quality assessments all demonstrate that image quality of retina-like sensor based on the feature of forward motion imaging is superior to that of rectilinear sensor.

Wang, Fan; Cao, Fengmei; Bai, Tingzhu; Luo, Zhihu; Su, Yulu

2014-11-01

361

Arsenic Exposure and Impaired Lung Function. Findings from a Large Population-based Prospective Cohort Study  

PubMed Central

Rationale: Exposure to arsenic through drinking water has been linked to respiratory symptoms, obstructive lung diseases, and mortality from respiratory diseases. Limited evidence for the deleterious effects on lung function exists among individuals exposed to a high dose of arsenic. Objectives: To determine the deleterious effects on lung function that exist among individuals exposed to a high dose of arsenic. Methods: In 950 individuals who presented with any respiratory symptom among a population-based cohort of 20,033 adults, we evaluated the association between arsenic exposure, measured by well water and urinary arsenic concentrations measured at baseline, and post-bronchodilator–administered pulmonary function assessed during follow-up. Measurements and Main Results: For every one SD increase in baseline water arsenic exposure, we observed a lower level of FEV1 (?46.5 ml; P < 0.0005) and FVC (?53.1 ml; P < 0.01) in regression models adjusted for age, sex, body mass index, smoking, socioeconomic status, betel nut use, and arsenical skin lesions status. Similar inverse relationships were observed between baseline urinary arsenic and FEV1 (?48.3 ml; P < 0.005) and FVC (?55.2 ml; P < 0.01) in adjusted models. Our analyses also demonstrated a dose-related decrease in lung function with increasing levels of baseline water and urinary arsenic. This association remained significant in never-smokers and individuals without skin lesions, and was stronger in male smokers. Among male smokers and individuals with skin lesions, every one SD increase in water arsenic was related to a significant reduction of FEV1 (?74.4 ml, P < 0.01; and ?116.1 ml, P < 0.05) and FVC (?72.8 ml, P = 0.02; and ?146.9 ml, P = 0.004), respectively. Conclusions: This large population-based study confirms that arsenic exposure is associated with impaired lung function and the deleterious effect is evident at low- to moderate-dose range. PMID:23848239

Parvez, Faruque; Chen, Yu; Yunus, Mahbub; Olopade, Christopher; Segers, Stephanie; Slavkovich, Vesna; Argos, Maria; Hasan, Rabiul; Ahmed, Alauddin; Islam, Tariqul; Akter, Mahmud M.; Graziano, Joseph H.

2013-01-01

362

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

363

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

PubMed

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

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

2013-04-26

364

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

365

Emission testing and inhalational exposure-based risk assessment for candles having Pb metal wick cores.  

PubMed

Segments of seven candles with wicks having a Pb metal core have been tested in a purpose-built combustion chamber to assess air Pb emissions. Emissions were collected on glass fibre filters that have been digested in concentrated HNO3 and analysed by flame atomic absorption spectroscopy (FAAS). Despite an indication of a bimodal distribution in Pb emission rates, and a range from 450 to 1130 micrograms Pb/h, the mean rate from the seven candles was 770 micrograms Pb/h. The 38-cm long candles are, on average, capable of emitting 104,000 micrograms of Pb into the air over approximately 127 h. A mean value of 20% of the Pb metal in the wick consumed by the candle is emitted into the air, the remainder appears to accumulate at the base of a molten wax-pool adjacent to the wick. Individual Pb-bearing particles from the combustion of candles were observed in a field emission scanning electron microscope (FESEM) to have a diameter of 1 micron or less. The emission from the candles has been analysed by X-ray diffraction (XRD) and identified as Sodium Lead Carbonate Hydroxide [NaPb2(CO3)2OH]. This compound, being a Pb carbonate, is likely to be easily absorbed in the lungs and gastrointestinal tract. Risks associated with inhalational exposure have been assessed after determining indoor lead in air (PbA) concentrations. Given a lack of information on the duration of use of candles, a range of scenarios from worst possible case to daily and weekly burning regimes are evaluated. Detailed evaluations of PbA are based on the emission from a single candle at rates of 500 and 1000 micrograms Pb/h, room volumes of 25 and 50 m3, durations of emission of 1.5, 3 and 6 h and air infiltration rates of 0, 0.25, 0.5, 0.75 and 1.0 air volume changes per hour (ACH). A candle burnt for 3 h at 1000 micrograms/h in a 50 m3 room having poor ventilation at 0.25 ACH is estimated to yield a 24-h average lead in air concentration of 9.9 micrograms/m3 with a peak PbA value of 42.1 micrograms/m3. Daily exposure to such candle burning where children spend 80% of their time indoors is likely to elevate PbB in children by a minimum of 24 to 40 micrograms/dl, according to the PbB:PbA relationship of Brunekreef, 1984 (The relationship between air lead and blood lead in children: a critical review). Estimating child Pb uptake from first principles using a range of exposure factors, a child would obtain some 85 to 127% of the provisional tolerable weekly Pb intake (PTWI) from such daily exposure. Child blood lead levels could readily exceed levels of 10 micrograms/dl, largely due to exposure to emissions from burning Pb wick core candles for several hours once per week. The regular burning of multiple candles in small, poorly ventilated spaces could readily be associated with clinical Pb poisonings and death. High levels of exposure could occur with Pb metal core wick candles in less developed countries where candles are used on a daily basis for indoor lighting purposes in small dwellings. Prolonged burning of candles may occur in religious and in ceremonial circumstances or restaurants where they may be of particular concern. On the basis of the limited investigation carried out, candles having a wick with a Pb metal core have the potential to present highly unacceptable and avoidable risks to human health. PMID:10635590

van Alphen, M

1999-12-15

366

Value and probability coding in a feedback-based learning task utilizing food rewards.  

PubMed

For the consequences of our actions to guide behavior, the brain must represent different types of outcome-related information. For example, an outcome can be construed as negative because an expected reward was not delivered or because an outcome of low value was delivered. Thus behavioral consequences can differ in terms of the information they provide about outcome probability and value. We investigated the role of the striatum in processing probability-based and value-based negative feedback by training participants to associate cues with food rewards and then employing a selective satiety procedure to devalue one food outcome. Using functional magnetic resonance imaging, we examined brain activity related to receipt of expected rewards, receipt of devalued outcomes, omission of expected rewards, omission of devalued outcomes, and expected omissions of an outcome. Nucleus accumbens activation was greater for rewarding outcomes than devalued outcomes, but activity in this region did not correlate with the probability of reward receipt. Activation of the right caudate and putamen, however, was largest in response to rewarding outcomes relative to expected omissions of reward. The dorsal striatum (caudate and putamen) at the time of feedback also showed a parametric increase correlating with the trialwise probability of reward receipt. Our results suggest that the ventral striatum is sensitive to the motivational relevance, or subjective value, of the outcome, while the dorsal striatum codes for a more complex signal that incorporates reward probability. Value and probability information may be integrated in the dorsal striatum, to facilitate action planning and allocation of effort. PMID:25339705

Tricomi, Elizabeth; Lempert, Karolina M

2015-01-01

367

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

PubMed

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. PMID:19883674

Emond, Claude; Raymer, James H; Studabaker, William B; Garner, C Edwin; Birnbaum, Linda S

2010-02-01

368

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

369

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

370

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

ERIC Educational Resources Information Center

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

Schaaf, Ryan

2012-01-01

371

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

372

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

373

Task-Based Core-Periphery Organization of Human Brain Dynamics  

PubMed Central

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

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

2013-01-01

374

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. During this reporting period, the technical and economic performances of the selected processes were evaluated using computer models and available literature. The results of these evaluations are summarized in this report.

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

2002-04-01

375

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

NASA Astrophysics Data System (ADS)

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

Pantaleev, Aleksandar; Josephson, John R.

2007-04-01

376

Neuronal activity in the primate hippocampal formation during a conditional association task based on the subject's location.  

PubMed

The hippocampal formation (HF) functions in two domains of memory: spatial and nonspatial associative memory. The HF includes the hippocampus proper, the dentate gyrus, and the subicular complex. Studies of spatial correlates of HF neuronal activity have revealed that a subject's location in space can impose critical constraints on patterns of neuronal activity in the HF. This report compares monkey HF neuronal responses in two kinds of stimulus-response association tasks (go/no-go tasks with symmetrical reinforcement). In a place-dependent, conditional, stimulus-response association (PCA) task, the subject's location was the condition upon which stimulus (object)-behavioral response association depended. In a place-in-dependent, simple, stimulus-response association (ISA) task, the object-behavioral response contingency was independent of the subject's location. Of 329 neurons recorded, the activity of 88 increased or decreased significantly in response to the presentation of an object during the PCA task. Responses of 17 neurons depended differentially on specific combinations of object, place, and behavior in the PCA task (specific-combination neurons). These specific-combination responses do not simply reflect object-behavioral response association in the PCA task, since neuronal responses in the same object-behavioral response association were not restored in the ISA task in which there was no dependence on the subject's location. This suggests the influence of location on HF neuronal responses in object-behavioral response association when the subject's location is imposed as a condition. Responses of 12 neurons differentiated the kind of object in the PCA task (object-differential neurons). In the ISA task, most object-differential responses diminished or disappeared. Since the HF object-differential responses elicited by the conditions imposed by the PCA task. Characteristics of the two neuron types suggest that HF neurons encode both stimulus percept and attributes such as the place where the stimulus is presented and the conditional relation imposed in the task. PMID:7623125

Eifuku, S; Nishijo, H; Kita, T; Ono, T

1995-07-01

377

Acid–base and ionic fluxes in rainbow trout ( Oncorhynchus mykiss) during exposure to chloramine-T  

Microsoft Academic Search

The effects of chloramine-T and its degradation products, sodium hypochlorite (NaOCl) and para-toluenesulphonamide (pTSA), on whole body acid–base and branchial and renal ion (Na+and Cl?) fluxes were examined in rainbow trout (Oncorhynchus mykiss). Exposure to chloramine-T (3.5 h, 18 mg l?1) resulted in increases in plasma total CO2 but no coincident rise in PaCO2 or reduction in blood pH. Exposure

Mark D. Powell; Steve F. Perry

1998-01-01

378

Prediction of residential radon exposure of the whole Swiss population: comparison of model-based predictions with measurement-based predictions.  

PubMed

Radon plays an important role for human exposure to natural sources of ionizing radiation. The aim of this article is to compare two approaches to estimate mean radon exposure in the Swiss population: model-based predictions at individual level and measurement-based predictions based on measurements aggregated at municipality level. A nationwide model was used to predict radon levels in each household and for each individual based on the corresponding tectonic unit, building age, building type, soil texture, degree of urbanization, and floor. Measurement-based predictions were carried out within a health impact assessment on residential radon and lung cancer. Mean measured radon levels were corrected for the average floor distribution and weighted with population size of each municipality. Model-based predictions yielded a mean radon exposure of the Swiss population of 84.1 Bq/m(3) . Measurement-based predictions yielded an average exposure of 78 Bq/m(3) . This study demonstrates that the model- and the measurement-based predictions provided similar results. The advantage of the measurement-based approach is its simplicity, which is sufficient for assessing exposure distribution in a population. The model-based approach allows predicting radon levels at specific sites, which is needed in an epidemiological study, and the results do not depend on how the measurement sites have been selected. PMID:23464847

Hauri, D D; Huss, A; Zimmermann, F; Kuehni, C E; Röösli, M

2013-10-01

379

Reproducible direct exposure environmental testing of metal-based magnetic media  

NASA Technical Reports Server (NTRS)

A flow geometry and flow rate for mixed flowing gas testing is proposed. Use of an impinging jet of humid polluted air can provide a uniform and reproducible exposure of coupons of metal-based magnetic media. Numerical analysis of the fluid flow and mass transfer in such as system has shown that samples confined within a distance equal to the nozzle radius on the surface of impingement are uniformly accessible to pollutants in the impinging gas phase. The critical factor is the nozzle height above the surface of impingement. In particular, the uniformity of exposure is less than plus/minus 2% for a volumetric flow rate of 1600 cm(exp 3)/minute total flow with the following specifications: For a one inch nozzle, the height of the nozzle opening above the stage should be 0.177 inches; for a 2 inch nozzle - 0.390 inches. Not only is the distribution uniform, but one can calculate the maximum delivery rate of pollutants to the samples for comparison with the observed deterioration.

Sides, Paul J.

1994-01-01

380

Risk-based approach for controlling beryllium exposure in a manufacturing environment  

SciTech Connect

There are many diverse uses for beryllium in both military and industrial applications. Unfortunately, there are certain worker health risks associated with the manufacture and production of beryllium products. Respiratory illnesses due to prolonged contact with beryllium particulate are of paramount concern. However, these health risks can be controlled provided that the appropriate protective measures to prevent worker exposure from beryllium are in place. But it is no1 always a straightforward process to identify exactly what the beryllium protective measures should be in order to realize a true risk savings. Without prudent attention to a systematic inquiry and suitable evaluative criteria, a program for controlling beryllium health risks can be lacking in completeness and overall effectiveness. One approach that took into account the necessary ingredients for risk-based determination of beryllium protective measures was developed for a beryllium operation at a Department of Energy (DOE) facility. The methodological framework that was applied at this facility, as well as a discussion of the final beryllium protective measures that were determined by this approach will be presented. Regulatory aspects for working with beryllium, as well as a risk-assessment strategy for ranking beryllium-handling activities with respect to exposure potential will also be discussed. The presentation will conclude with a synopsis of lessons-learned as gleaned from this case study, as well as providing the participants with a constructive blueprint that can be adapted to other processes involving beryllium.

Gilmore, W. E. (Walter E.); Clawson, C. D. (Chris D.); Ellis, K. K. (Kimberly K.)

2003-01-01

381

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

382

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

383

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

PubMed Central

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

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

2013-01-01

384

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

PubMed

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

Patterson, Robert; Bracken, T; Alldredge, J

2005-02-01

385

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

PubMed Central

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

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

2014-01-01

386

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

EPA Science Inventory

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

387

Transfer Between Local and Global Processing Levels by Pigeons (Columba livia) and Humans (Homo sapiens) in Exemplar- and Rule-Based Categorization Tasks.  

PubMed

The present experiment investigated pigeons' and humans' processing styles-local or global-in an exemplar-based visual categorization task in which category membership of every stimulus had to be learned individually, and in a rule-based task in which category membership was defined by a perceptual rule. Group Intact was trained with the original pictures (providing both intact local and global information), Group Scrambled was trained with scrambled versions of the same pictures (impairing global information), and Group Blurred was trained with blurred versions (impairing local information). Subsequently, all subjects were tested for transfer to the 2 untrained presentation modes. Humans outperformed pigeons regarding learning speed and accuracy as well as transfer performance and showed good learning irrespective of group assignment, whereas the pigeons of Group Blurred needed longer to learn the training tasks than the pigeons of Groups Intact and Scrambled. Also, whereas humans generalized equally well to any novel presentation mode, pigeons' transfer from and to blurred stimuli was impaired. Both species showed faster learning and, for the most part, better transfer in the rule-based than in the exemplar-based task, but there was no evidence of the used processing mode depending on the type of task (exemplar- or rule-based). Whereas pigeons relied on local information throughout, humans did not show a preference for either processing level. Additional tests with grayscale versions of the training stimuli, with versions that were both blurred and scrambled, and with novel instances of the rule-based task confirmed and further extended these findings. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25150965

Aust, Ulrike; Braunöder, Elisabeth

2014-08-25

388

Neuromuscular response of the trunk to inertial based sudden perturbations following whole body vibration exposure.  

PubMed

The effects of whole body vibration exposure on the neuromuscular responses following inertial-based trunk perturbations were examined. Kinematic and surface EMG (sEMG) data were collected while subjects were securely seated on a robotic platform. Participants were either exposed to 10min of vibration or not, which was followed by sudden inertial trunk perturbations with and without timing and direction knowledge. Amplitude of sEMG was analyzed for data collected during the vibration protocol, whereas the onset of sEMG activity and lumbar spine angle were analyzed for the perturbation protocol. Data from the vibration protocol did not show a difference in amplitude of sEMG for participants exposed to vibration and those not. The perturbation protocol data showed that those not exposed to vibration had a 14% faster muscle onset, despite data showing no difference in fatigue level. PMID:25241645

MacIntyre, Danielle; Cort, Joel A

2014-12-01

389

Low-cost extrapolation method for maximal LTE radio base station exposure estimation: test and validation.  

PubMed

An experimental validation of a low-cost method for extrapolation and estimation of the maximal electromagnetic-field exposure from long-term evolution (LTE) radio base station installations are presented. No knowledge on downlink band occupation or service characteristics is required for the low-cost method. The method is applicable in situ. It only requires a basic spectrum analyser with appropriate field probes without the need of expensive dedicated LTE decoders. The method is validated both in laboratory and in situ, for a single-input single-output antenna LTE system and a 2×2 multiple-input multiple-output system, with low deviations in comparison with signals measured using dedicated LTE decoders. PMID:23179190

Verloock, Leen; Joseph, Wout; Gati, Azeddine; Varsier, Nadège; Flach, Björn; Wiart, Joe; Martens, Luc

2013-06-01

390

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

PubMed Central

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

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

2015-01-01

391

Health and Human Services Cluster. Task Analyses. Physical Therapist Aide and Physical Therapist Assistant. A Competency-Based Curriculum Guide.  

ERIC Educational Resources Information Center

Developed in Virginia, this publication contains task analysis guides to support selected tech prep programs that prepare students for careers in the health and human services cluster. Occupations profiled are physical therapist aide and physical therapist assistant. Each guide contains the following elements: (1) an occupational task list derived…

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

392

A touch screen based stop signal response task in rhesus monkeys for studying impulsivity associated with chronic cocaine self-administration  

PubMed Central

Among a range of cognitive deficits, human cocaine addicts display increased impulsivity and decreased performance monitoring. In order to establish an animal model that can be used to study the underlying neurobiology of these deficits associated with addiction, we have developed a touch screen based Stop Signal Response Task for rhesus monkeys. This task is essentially identical to the clinically used Stop Signal Task employed for diagnostic and research purposes. In this task, impulsivity is reflected in the amount of time needed to inhibit a response after it has been initiated, the Stop Signal Response Time (SSRT). Performance monitoring is reflected by the slowing of response times following Stop trials (Post-Stop Slowing, PSS). Herein we report on the task structure, the staged methods for training animals to perform the task, and a comparison of performance values for control and cocaine experienced animals. Relative to controls, monkeys that had self-administered cocaine, followed by 18 months abstinence, displayed increased impulsivity (increased SSRT values), and decreased performance monitoring (decreased PSS values). Our results are consistent with human data, and thereby establish an ideal animal model for studying the etiology and underlying neurobiology of cocaine-induced impulse control and performance monitoring deficits. PMID:18948136

Liu, Shijing; Heitz, Richard P.; Bradberry, Charles W.

2009-01-01

393

Determinants of dermal exposure relevant for exposure modelling in regulatory risk assessment.  

PubMed

Risk assessment of chemicals requires assessment of the exposure levels of workers. In the absence of adequate specific measured data, models are often used to estimate exposure levels. For dermal exposure only a few models exist, which are not validated externally. In the scope of a large European research programme, an analysis of potential dermal exposure determinants was made based on the available studies and models and on the expert judgement of the authors of this publication. Only a few potential determinants appear to have been studied in depth. Several studies have included clusters of determinants into vaguely defined parameters, such as 'task' or 'cleaning and maintenance of clothing'. Other studies include several highly correlated parameters, such as 'amount of product handled', 'duration of task' and 'area treated', and separation of these parameters to study their individual influence is not possible. However, based on the available information, a number of determinants could clearly be defined as proven or highly plausible determinants of dermal exposure in one or more exposure situation. This information was combined with expert judgement on the scientific plausibility of the influence of parameters that have not been extensively studied and on the possibilities to gather relevant information during a risk assessment process. The result of this effort is a list of determinants relevant for dermal exposure models in the scope of regulatory risk assessment. The determinants have been divided into the major categories 'substance and product characteristics', 'task done by the worker', 'process technique and equipment', 'exposure control measures', 'worker characteristics and habits' and 'area and situation'. To account for the complex nature of the dermal exposure processes, a further subdivision was made into the three major processes 'direct contact', 'surface contact' and 'deposition'. PMID:14602668

Marquart, J; Brouwer, D H; Gijsbers, J H J; Links, I H M; Warren, N; van Hemmen, J J

2003-11-01

394

Spatiotemporal air pollution exposure assessment for a Canadian population-based lung cancer case-control study  

PubMed Central

Background Few epidemiological studies of air pollution have used residential histories to develop long-term retrospective exposure estimates for multiple ambient air pollutants and vehicle and industrial emissions. We present such an exposure assessment for a Canadian population-based lung cancer case-control study of 8353 individuals using self-reported residential histories from 1975 to 1994. We also examine the implications of disregarding and/or improperly accounting for residential mobility in long-term exposure assessments. Methods National spatial surfaces of ambient air pollution were compiled from recent satellite-based estimates (for PM2.5 and NO2) and a chemical transport model (for O3). The surfaces were adjusted with historical annual air pollution monitoring data, using either spatiotemporal interpolation or linear regression. Model evaluation was conducted using an independent ten percent subset of monitoring data per year. Proximity to major roads, incorporating a temporal weighting factor based on Canadian mobile-source emission estimates, was used to estimate exposure to vehicle emissions. A comprehensive inventory of geocoded industries was used to estimate proximity to major and minor industrial emissions. Results Calibration of the national PM2.5 surface using annual spatiotemporal interpolation predicted historical PM2.5 measurement data best (R2 = 0.51), while linear regression incorporating the national surfaces, a time-trend and population density best predicted historical concentrations of NO2 (R2 = 0.38) and O3 (R2 = 0.56). Applying the models to study participants residential histories between 1975 and 1994 resulted in mean PM2.5, NO2 and O3 exposures of 11.3 ?g/m3 (SD = 2.6), 17.7 ppb (4.1), and 26.4 ppb (3.4) respectively. On average, individuals lived within 300 m of a highway for 2.9 years (15% of exposure-years) and within 3 km of a major industrial emitter for 6.4 years (32% of exposure-years). Approximately 50% of individuals were classified into a different PM2.5, NO2 and O3 exposure quintile when using study entry postal codes and spatial pollution surfaces, in comparison to exposures derived from residential histories and spatiotemporal air pollution models. Recall bias was also present for self-reported residential histories prior to 1975, with cases recalling older residences more often than controls. Conclusions We demonstrate a flexible exposure assessment approach for estimating historical air pollution concentrations over large geographical areas and time-periods. In addition, we highlight the importance of including residential histories in long-term exposure assessments. For submission to: Environmental Health PMID:22475580

2012-01-01

395

Conceptual design of a lunar base solar power plant lunar base systems study task 3.3  

NASA Technical Reports Server (NTRS)

The best available concepts for a 100 kW Solar Lunar Power Plant based on static and dynamic conversion concepts have been examined. The two concepts which emerged for direct comparison yielded a difference in delivered mass of 35 MT, the mass equivalent of 1.4 lander payloads, in favor of the static concept. The technologies considered for the various elements are either state-of-the-art or near-term. Two photovoltaic cell concepts should receive high priority for development: i.e., amorphous silicon and indium phosphide cells. The amorphous silicon, because it can be made so light weight and rugged; and the indium phosphide, because it shows very high efficiency potential and is reportedly not degraded by radiation. Also the amorphous silicon cells may be mounted on flexible backing that may roll up much like a carpet for compact storage, delivery, and ease of deployment at the base. The fuel cell and electrolysis cell technology is quite well along for lunar base applications, and because both the Shuttle and the forthcoming Space Station incorporate these devices, the status quo will be maintained. Early development of emerging improvements should be implemented so that essential life verification test programs may commence.

1988-01-01

396

Long Duration Exposure Facility experiment M0003 deintegration observation data base  

NASA Technical Reports Server (NTRS)

The four trays (2 leading edge and 2 trailing edge) of the M0003 materials experiment on the Long Duration Exposure Facility (LDEF) contained 1274 samples from 20 subexperiments. The complete sample complement represented a broad range of materials, including thin film optical coatings, paints, polymer sheets and tapes, adhesives, and composites, for use in various spacecraft applications, including thermal control, structures, optics, and solar power. Most subexperiments contained sets of samples exposed on both the leading and trailing edge trays of LDEF. Each individual sample was examined by high resolution optical microscope during the deintegration of the subexperiments from the M0003 trays. Observations of the post-flight condition of the samples made during this examination were recorded in a computer data base. The deintegration observation data base is available to requesters on floppy disk in 4th Dimension for the Macintosh format. Over 3,000 color macrographs and photomicrographs were shot to complement the observation records and to document the condition of the individual samples and of the M0003 trays. The photographs provide a visual comparison of the response of materials in leading and trailing edge LDEF environments. The Aerospace Corporate Archives is distributing photographs of the samples and hard copies of the database records to the general public upon request. Information on obtaining copies of the data base disks and for ordering photographs and records of specific samples or materials are given.

Gyetvay, S. R.; Coggi, J. M.; Meshishnek, M. J.

1993-01-01

397

Task-specific effects of reward on task switching.  

PubMed

Although cognitive control and reinforcement learning have been researched extensively over the last few decades, only recently have studies investigated their interrelationship. An important unanswered question concerns how the control system decides what task to execute and how vigorously to carry out the task once selected. Based on a recent theory of control formulated according to principles of hierarchical reinforcement learning, we asked whether rewards can affect top-down control over task performance at the level of task representation. Participants were rewarded for correctly performing only one of two tasks in a standard task-switching experiment. Reaction times and error rates were lower for the reinforced task compared to the non-reinforced task. Moreover, the switch cost in error rates for the non-reinforced task was significantly larger compared to the reinforced task, especially for trials in which the imperative stimulus afforded different responses for the two tasks, resulting in a "non-paradoxical" asymmetric switch cost. These findings suggest that reinforcement at the task level resulted in greater application of top-down control rather than in stronger stimulus-response pathways for the rewarded task. PMID:24984832

Umemoto, Akina; Holroyd, Clay B

2014-07-01

398

4C/ID in medical education: How to design an educational program based on whole-task learning: AMEE Guide No. 93.  

PubMed

Medical education increasingly stresses that medical students should be prepared to take up multiple roles as a health professional. This requires the integrated acquisition of multiple competences such as clinical reasoning and decision making, communication skills and management skills. To promote such complex learning, instructional design has focused on the use of authentic, real-life learning tasks that students perform in a real or simulated task environment. The four-component instructional design model (4C/ID) model is an instructional design model that starts from the use of such tasks and provides students with a variety of learning tools facilitating the integrated acquisition of knowledge, skills and attitudes. In what follows, we guide the reader on how to implement educational programs based on the 4C/ID model and illustrate this with an example from general practice education. The developed learning environment is in line with the whole-task approach, where a learning domain is considered as a coherent, integrated whole and where teaching progresses from offering relatively simple, but meaningful, authentic whole tasks to more complex tasks. We describe the steps that were taken, from prototype over development to implementation, to build five learning modules (patient with diabetes; the young child with fever; axial skeleton; care for the elderly and physically undefined symptoms) that all focus on the integrated acquisition of the Canadian Medical Education Directives for Specialists roles in general practice. Furthermore, a change cycle for educational innovation is described that encompasses practice-based challenges and pitfalls about the collaboration between different stakeholders (students, developers and teachers) and the transition from traditional, fragmented and classroom-based learning to integrated and blended learning based on sound instructional design principles. PMID:25053377

Vandewaetere, Mieke; Manhaeve, Dominique; Aertgeerts, Bert; Clarebout, Geraldine; Van Merriënboer, Jeroen J G; Roex, Ann

2015-01-01

399

Strategic backdrop analysis for fossil fuel planning. Task 2 report (New Task Series), The Base Case. Report 473-117-08/01  

SciTech Connect

This report describes a base case analysis performed using the strategic backdrop analytical framework developed by The Futures Group to facilitate fossil fuel planning within the Department of Energy. It builds upon the data base compiled in the default case previously submitted but uses a different set of energy technology assumptions. Objectives of the strategic backdrop analysis project are: (1) to delineate alternative socioeconomic futures or target worlds for the United States and to derive, for each world, the amount of energy needed to sustain its level of economic activity and lifestyle, assuming no technological changes; (2) to construct an analytical framework that accounts for the flow of energy from the disaggregated end-use target demand sectors back through the distribution and conversion processes to primary resource requirements; (3) to use this framework 1) to analyze how alternative government policies and associated new technologies can change the primary resource needs and fuel mix while still providing the same level of end-use energy service for the target world, and 2) to highlight resource constraints, program inconsistencies, and economic, environmental, and social implications; (4) to transfer to DOE personnel the methodology for generating energy targets and accounting for important characteristics of alternative energy policies and technologies.

Not Available

1980-08-01

400

Learning Tasks  

ERIC Educational Resources Information Center

Government budget constraints had forced the Emergency Dispatch Center (EDC) at a military installation to work with less than the normal number of staff. A Program Proposal was developed previously that had determined that a learning gap existed in the researcher's work environment at a military installation. To counter this gap, Learning Tasks

Baskas, Richard S.

2012-01-01

401

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

USGS Publications Warehouse

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

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

2012-01-01

402

Effects of a Perseverative Interest-Based Token Economy on Challenging and On-Task Behavior in a Child with Autism  

ERIC Educational Resources Information Center

We compared the effects of a token economy intervention that either did or did not include the perseverative interests of a 7-year-old boy with autism. An alternating treatment design revealed that the perseverative interest-based tokens were more effective at decreasing challenging behavior and increasing on-task behavior than tokens absent the…

Carnett, Amarie; Raulston, Tracy; Lang, Russell; Tostanoski, Amy; Lee, Allyson; Sigafoos, Jeff; Machalicek, Wendy

2014-01-01

403

Courseware Integration into Task-Based Learning: A Case Study of Multimedia Courseware-Supported Oral Presentations for Non-English Major Students  

ERIC Educational Resources Information Center

This study reports on the integration of English for Specific Purposes (ESP) multimedia courseware for oral presentations into a self-learning and elective program for non-English major students in an English as a Foreign Language (EFL) setting. A computer-aided instruction approach, combined with a task-based learning approach, was adopted.…

Tsai, Shu-Chiao

2011-01-01

404

A Function-Based Intervention to Increase a Second-Grade Student's On-Task Behavior in a General Education Classroom  

ERIC Educational Resources Information Center

A functional assessment-based intervention (FABI) was designed and implemented to increase the on-task behavior of David, a second-grade student in a general education classroom. David attended an elementary school that used a comprehensive, integrated, three-tiered (CI3T) model of prevention. The school's principal nominated David for Project…

Germer, Kathryn A.; Kaplan, Lauren M.; Giroux, Lindsay N.; Markham, Elizabeth H.; Ferris, Geoffrey J.; Oakes, Wendy P.; Lane, Kathleen Lynne

2011-01-01

405

An architecture for intelligent task interruption  

NASA Technical Reports Server (NTRS)

In the design of real time systems the capability for task interruption is often considered essential. The problem of task interruption in knowledge-based domains is examined. It is proposed that task interruption can be often avoided by using appropriate functional architectures and knowledge engineering principles. Situations for which task interruption is indispensable, a preliminary architecture based on priority hierarchies is described.

Sharma, D. D.; Narayan, Srini

1990-01-01

406

The Workplace Exposure Assessment Expert System (WORKSPERT)  

SciTech Connect

The fundamental principles of industrial hygiene are based upon the recognition, evaluation, and control of workplace hazards. Occupational safety and health professionals (e.g., industrial hygienists) perform this task by assessing numerous complex factors. In many situations industrial hygienists are not available; therefore, an expert system has been developed to assist the performance of workplace exposure assessments (WEAs). The Workplace Exposure Assessment Expert System (WORKSPERT) evaluates various hazardous substances, workplace conditions, and worker exposures for designated homogeneous exposure groups (HEGs). The three major components of WORKSPERT (i.e., substance, workplace, and exposure factors) are described by 27 multiple attribute variables. An air monitoring program (AMP) may be recommended for each HEG based upon the WEA. The AMP provides recommendations for an appropriate sampling strategy, sampling duration, multiple substance exposures, and number of samples to be obtained in the future. The use of WORKSPERT or other expert systems should never supersede the judgment of occupational safety and health professionals. However, WORKSPERT can be a valuable tool when used by knowledgeable, qualified technical professionals who understand the specific substance, workplace, and exposure factors for designated HEGs. WORKSPERT allows these people to benefit from the expertise of an industrial hygienist by performing systematic evaluations and obtaining recommendations for corrective actions or an AMP. The use of WORKSPERT to perform WEAs promotes the protection of workers from hazardous substances and assists compliance with occupational safety and health regulations. It also facilitates the communication of substance hazards, workplace controls, and worker exposures in a succinct manner.

Tait, K. (Pfizer Inc., New York, NY (United States))

1992-02-01

407

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

PubMed

The aim of this work was to study possible effects of environmental radiation pollution on plants. The association between cellular telephone (short duration, higher amplitude) and base station (long duration, very low amplitude) radiation exposure and the growth rate of soybean (Glycine max) seedlings was investigated. Soybean seedlings, pre-grown for 4 days, were exposed in a gigahertz transverse electromagnetic cell for 2?h to global system for mobile communication (GSM) mobile phone pulsed radiation or continuous wave (CW) radiation at 900?MHz with amplitudes of 5.7 and 41?V?m(-1) , and outgrowth was studied one week after exposure. The exposure to higher amplitude (41?V?m(-1) ) GSM radiation resulted in diminished outgrowth of the epicotyl. The exposure to lower amplitude (5.7?V?m(-1) ) GSM radiation did not influence outgrowth of epicotyl, hypocotyls, or roots. The exposure to higher amplitude CW radiation resulted in reduced outgrowth of the roots whereas lower CW exposure resulted in a reduced outgrowth of the hypocotyl. Soybean seedlings were also exposed for 5 days to an extremely low level of radiation (GSM 900?MHz, 0.56?V?m(-1) ) and outgrowth was studied 2 days later. Growth of epicotyl and hypocotyl was found to be reduced, whereas the outgrowth of roots was stimulated. Our findings indicate that the observed effects were significantly dependent on field strength as well as amplitude modulation of the applied field. Bioelectromagnetics. 36:87-95, 2015. © 2015 Wiley Periodicals, Inc. PMID:25644316

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

2015-02-01

408

Performance Evaluation of Scheduling Mechanism with Checkpoint Sharing and Task Duplication in P2P-Based PC Grid Computing  

Microsoft Academic Search

An important issue in the PC grid computing environment that is characterized by volatility and heterogeneity is the minimization\\u000a of execution time for all tasks. This paper proposes a scheduling mechanism to reduce such execution time by means of both\\u000a checkpoint sharing and task duplication under a peer-to-peer (P2P) architecture. In the mechanism, the checkpoint executed\\u000a by an individual peer

Joon-min Gil; Ui-sung Song; Heon-chang Yu

2009-01-01

409

Scenarios and task analysis  

Microsoft Academic Search

A Critical Review of Carroll's book on scenario-based design is offered [Making Use: Scenario-Based Design of Human–Computer Interactions (2000)]. Carroll characterises scenarios as ‘stories about use’. The paper demonstrates that Carroll's proposals about scenarios and their use in software engineering can be fitted into the broader framework of task analysis in Human–Computer Interaction.

Dan Diaper

2002-01-01

410

Occupational exposures and chronic respiratory symptoms. A population-based study  

SciTech Connect

Data from a random sample of 8515 white adults residing in 6 cities in the eastern and midwestern United States were used to examine the relationships between occupational exposures to dust or to gases and fumes and chronic respiratory symptoms; 31% of the population had a history of occupational dust exposure and 30% reported exposure to gas or fumes. After adjusting for smoking habits, age, gender, and city of residence, subjects with either occupational exposure had significantly elevated prevalences of chronic cough, chronic phlegm, persistent wheeze, and breathlessness. The adjusted relative odds of chronic respiratory symptoms for subjects exposed to dust ranged from 1.32 to 1.60. Subjects with gas or fume exposure had relative odds of symptoms between 1.27 and 1.43 when compared with unexposed subjects. Occupational dust exposure was associated with a higher prevalence of chronic obstructive pulmonary disease as defined by an FEV1/FVC ratio of less than 0.6, when comparing exposed and unexposed participants (OR = 1.53, 95% Cl = 1.17-2.08). Gas or fume exposure was associated with a small, but not significant, increase in COPD prevalence. Significant trends were noted for wheeze and phlegm with increasing duration of dust exposure. Although 36% of exposed subjects reported exposure to both dust and fumes, there was no evidence of a multiplicative interaction between the effects of the individual exposures. Smoking was a significant independent predictor of symptoms, but did not appear to modify the effect of dust or fumes on symptom reporting. These data, obtained in random samples of general populations, demonstrate that chronic respiratory symptoms and disease can be independently associated with occupational exposures.

Korn, R.J.; Dockery, D.W.; Speizer, F.E.; Ware, J.H.; Ferris, B.G. Jr.

1987-08-01

411

Occupational exposures and chronic respiratory symptoms: a population-based study  

SciTech Connect

Data from a random sample of 8515 white adults residing in six cities in the eastern and midwestern United States were used to examine the relationships between occupational exposures to dust or to gases and fumes and chronic respiratory symptoms. 31% of the population had a history of occupational dust exposure and 30% reported exposure to gas or to fumes. After adjusting for smoking habits, age, gender, and city of residence, subjects with either occupational exposure had significantly elevated prevalence of chronic cough, chronic phlegm, persistent wheeze, and breathlessness. The adjusted relative odds of chronic respiratory symptoms for subjects exposed to dust ranged from 1.32 to 1.60. Subjects with gas or fume exposure had relative odds of symptoms between 1.27 and 1.43 when compared to unexposed subjects. Occupational dust exposure was associated with a higher prevalence of chronic obstructive pulmonary disease (COPD) as defined by an FEV1/FVC ratio of less than 0.6, when comparing exposed and unexposed participants (OR=1.53, 95% CI=1.17-2.08). Gas or fume exposure was associated with a small, but not significant, increase in COPD prevalence. Significant trends were noted for wheeze and phlegm with increasing duration of dust exposure. Although 36% of exposed subjects reported exposure to both dust and fumes, there was no evidence of a multiplicative interaction between the effects of the individual exposures. Smoking was a significant independent predictor of symptoms, but did not appear to modify the effect of dust or fumes on symptom reporting. These data, obtained in random samples of general populations, demonstrate that chronic respiratory disease can be independently associated with occupational exposures.

Korn, R.J.; Dockery, D.W.; Speizer, F.E.; Ware, J.H.; Ferris, B.G.

1987-01-01

412

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

PubMed Central

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

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

2014-01-01

413

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

PubMed Central

Purpose: A numerical model and the experimental methods to study the x-ray exposure dependent change in the modulation transfer function (MTF) of amorphous selenium (a-Se) based active matrix flat panel imagers (AMFPIs) are described. The physical mechanisms responsible for the x-ray exposure dependent change in MTF are also investigated. Methods: A numerical model for describing the x-ray exposure dependent MTF of a-Se based AMFPIs has been developed. The x-ray sensitivity and MTF of an a-Se AMFPI have been measured as a function of exposure. The instantaneous electric field and free and trapped carrier distributions in the photoconductor layer are obtained by numerically solving the Poisson’s equation, continuity equations, and trapping rate equations using the backward Euler finite difference method. From the trapped carrier distributions, a method for calculating the MTF due to incomplete charge collection is proposed. Results: The model developed in this work and the experimental data show a reasonably good agreement. The model is able to simultaneously predict the dependence of the sensitivity and MTF on accumulated exposure at different applied fields and bias polarities, with the same charge transport parameters that are typical of the particular a-Se photoconductive layer that is used in these AMFPIs. Under negative bias, the MTF actually improves with the accumulated x-ray exposure while the sensitivity decreases. The MTF enhancement with exposure decreases with increasing applied field. Conclusions: The most prevalent processes that control the MTF under negative bias are the recombination of drifting holes with previously trapped electrons (electrons remain in deep traps due to their long release times compared with the time scale of the experiments) and the deep trapping of drifting holes and electrons. PMID:20384271

Kabir, M. Z.; Chowdhury, L.; DeCrescenzo, G.; Tousignant, O.; Kasap, S. O.; Rowlands, J. A.

2010-01-01

414

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

SciTech Connect

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

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

2010-03-15

415

A coordinate-based ALE functional MRI meta-analysis of brain activation during verbal fluency tasks in healthy control subjects  

PubMed Central

Background The processing of verbal fluency tasks relies on the coordinated activity of a number of brain areas, particularly in the frontal and temporal lobes of the left hemisphere. Recent studies using functional magnetic resonance imaging (fMRI) to study the neural networks subserving verbal fluency functions have yielded divergent results especially with respect to a parcellation of the inferior frontal gyrus for phonemic and semantic verbal fluency. We conducted a coordinate-based activation likelihood estimation (ALE) meta-analysis on brain activation during the processing of phonemic and semantic verbal fluency tasks involving 28 individual studies with 490 healthy volunteers. Results For phonemic as well as for semantic verbal fluency, the most prominent clusters of brain activation were found in the left inferior/middle frontal gyrus (LIFG/MIFG) and the anterior cingulate gyrus. BA 44 was only involved in the processing of phonemic verbal fluency tasks, BA 45 and 47 in the processing of phonemic and semantic fluency tasks. Conclusions Our comparison of brain activation during the execution of either phonemic or semantic verbal fluency tasks revealed evidence for spatially different activation in BA 44, but not other regions of the LIFG/LMFG (BA 9, 45, 47) during phonemic and semantic verbal fluency processing. PMID:24456150

2014-01-01

416

A case study of a precision fertilizer application task generation for wheat based on classified hyperspectral data from UAV combined with farm history data  

NASA Astrophysics Data System (ADS)

Different remote sensing methods for detecting variations in agricultural fields have been studied in last two decades. There are already existing systems for planning and applying e.g. nitrogen fertilizers to the cereal crop fields. However, there are disadvantages such as high costs, adaptability, reliability, resolution aspects and final products dissemination. With an unmanned aerial vehicle (UAV) based airborne methods, data collection can be performed cost-efficiently with desired spatial and temporal resolutions, below clouds and under diverse weather conditions. A new Fabry-Perot interferometer based hyperspectral imaging technology implemented in an UAV has been introduced. In this research, we studied the possibilities of exploiting classified raster maps from hyperspectral data to produce a work task for a precision fertilizer application. The UAV flight campaign was performed in a wheat test field in Finland in the summer of 2012. Based on the campaign, we have classified raster maps estimating the biomass and nitrogen contents at approximately stage 34 in the Zadoks scale. We combined the classified maps with farm history data such as previous yield maps. Then we generalized the combined results and transformed it to a vectorized zonal task map suitable for farm machinery. We present the selected weights for each dataset in the processing chain and the resultant variable rate application (VRA) task. The additional fertilization according to the generated task was shown to be beneficial for the amount of yield. However, our study is indicating that there are still many uncertainties within the process chain.

Kaivosoja, Jere; Pesonen, Liisa; Kleemola, Jouko; Pölönen, Ilkka; Salo, Heikki; Honkavaara, Eija; Saari, Heikki; Mäkynen, Jussi; Rajala, Ari

2013-10-01

417

Detailed exposure assessment of dietary furan for infants consuming commercially jarred complementary food based on data from the DONALD study.  

PubMed

Furan is a possible human carcinogen regularly occurring in commercially jarred complementary foods. This paper will provide a detailed exposure assessment for babies consuming these foods considering different intake scenarios. The occurrence data on furan in complementary foods were based on our own headspace-gas chromatography/mass spectrometry (HS-GC/MS) analytical results (n = 286). The average furan content in meals and menus was between 20 and 30 µg kg(-1), which is in excellent agreement with results from other European countries. Using measured food consumption data from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study, the average exposures for consumers of commercially jarred foods ranged between 182 and 688 ng kg(-1) bw day(-1), with a worst case scenario for P95 consumers ranging between 351 and 1066 ng kg(-1) bw day(-1). The exposure data were then used to characterize risk using the margin of exposure method based on a benchmark dose lower confidence limit for a 10% response (BMDL10) of 1.28 mg kg(-1) bw day(-1) for hepatocellular tumours in rats. The margin of exposures (MOEs) were below the threshold of 10 000, which is often used to define public health risks, in all scenarios, ranging between 7022 and 1861 for average consumers and between 3642 and 1200 for the P95 consumers. Mitigative measures to avoid furan in complementary foods should be of high priority for risk management. PMID:21176106

Lachenmeier, Dirk W; Maser, Elena; Kuballa, Thomas; Reusch, Helmut; Kersting, Mathilde; Alexy, Ute