WorldWideScience

Sample records for surface impoundments task

  1. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the actions that were taken to clean close the TA-35 TSL-125 surface impoundment Building 125 is used for developing electron guns and related laser assemblies/equipment for a Laser Technology Research Program at the Laboratory. There is no permanent outfall from the surface impoundment; however, the impoundment accidentally overtopped on December 3, 1986, spilling an unknown volume of insulating oil and water into Ten Site Canyon. Sandbags were installed around the surface impoundment on June 25, 1988, to provide additional freeboard in the impoundment and reduce the risk of overtopping during a precipitation event. On July 1, 1988, the impoundment again overtopped releasing an unknown volume of insulating oil and water. Actions taken include removal of waste from the surface impoundment and its associated structures, decontamination of the floor trough and piping inside Building 125, grouting of the piping connecting the floor drain/trough system to the impoundment, decontamination, removal, and disposal of the impoundment liner and sandbags lining the top of the impoundment, and removal and disposal of contaminated soil underlying the impoundment area. Procedures followed to verify that clean closure objectives have been met are also documented in this report. Initial verification was performed through an extensive soil sampling and analysis program

  2. 40 CFR 268.4 - Treatment surface impoundment exemption.

    Science.gov (United States)

    2010-07-01

    ... residues may not be placed in any other surface impoundment for subsequent management. (iv) Recordkeeping... exemption. 268.4 Section 268.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID...), the residues from treatment are analyzed, as specified in § 268.7 or § 268.32, to determine if they...

  3. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This closure report documents closure activities for the TA-35 TSL-125 surface impoundment and associated structures at Los Alamos National Laboratory (the Laboratory). Prior to formal approval of the closure plan, the decision was made to proceed with closure activities to prevent any further releases from the site following informal discussions with New Mexico Environment Department (NMED) personnel. The closure plan is a revision of the previously submitted draft dated July 1988. Clean closure of the TSL-125 site was accomplished through: Removal and proper disposal of all wastes contained within the surface impoundment system; Decontamination and/or removal and proper disposal of the surface impoundment, its associated structures, and contaminated soil underlying the impoundment area; Sampling and analysis of soil to determine the presence and concentrations of any hazardous constituents remaining in the soil at the TSL-125 site; and Demonstration through a risk assessment that any constituents remaining in the soil at the TSL-125 site pose no threat to human health and the environment. All remaining soil concentrations of hazardous constituents were below health-based action levels. Analytical results indicated that benzidine, n-nitrosodimethylamine, and n-nitrosodi-n-propylamine were not detected at or above their limits of quantitation and beryllium was not present at or above its laboratory detection limit. However, the limits of quantitation and detection for these constituents were greater than their calculated health-based action levels. To demonstrate that these constituents were not present, historical data was researched and it was determined that the constituents were not utilized at the Building 125 site. 4 refs., 8 figs., 1 tab

  4. Transport and dispersion of pollutants in surface impoundments: a finite difference model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model by finite-difference (SIMFD) has been developed. SIMFD computes the flow rate, velocity field, and the concentration distribution of pollutants in surface impoundments with any number of islands located within the region of interest. Theoretical derivations and numerical algorithm are described in detail. Instructions for the application of SIMFD and listings of the FORTRAN IV source program are provided. Two sample problems are given to illustrate the application and validity of the model.

  5. An experimental approach to determining subsurface leakage from a surface impoundment using a radioisotope tracer

    International Nuclear Information System (INIS)

    Ashwood, T.L.; Story, J.D.; Larsen, I.L.; Schultz, F.J.

    1987-01-01

    Bromine-82, a 35.3-h half-life radionuclide, was used as a tracer to determine the paths and rates of leakage from an unlined, 1,000,000-gal (3,785,000 L), surface impoundment at the Oak Ridge National Laboratory. Since the impoundment is underlain and surrounded by storm sewer and sanitary sewer lines (most of them predating the impoundment), known and suspected leak sites in storm drain catch basins and sanitary sewer manholes were sampled periodically and analyzed for 82 Br. A series of four ground water monitoring wells - three downgradient and one upgradient from the impoundment - were also sampled for 82 Br. Although the catch basin and manhole samples picked up 82 Br in leakage from the impoundment less than 5 h after application of the tracer, the monitoring well samples did not contain detectable levels of the radionuclide. It was concluded that the monitoring wells were sampling groundwater moving through the formation, whereas the storm drains and manholes were sampling water leading rapidly through secondary porosity and along preferred pathways. The decline in tracer concentration as a function of time was used to determine the residence time of water in the pond and hence the flow rate through the pond. This flow rate, when compared with the known outflow rate, indicated that the leakage flow was small. Hence, the main value of the test was to identify rapid leakage pathways. The experiment demonstrates the need for sampling subsurface drain systems as part of an integrated monitoring system for leak detection. The effectiveness of 82 Br as a tracer for rapid leaks was also shown

  6. Technical work plan for Surface Impoundments Operable Unit engineering support studies

    International Nuclear Information System (INIS)

    1995-11-01

    This document provides a comprehensive work plan which, when utilized as a data collection guide for field activities, will provide the necessary information required to complete a report on geotechnical properties of the sediments contained in the Surface Impoundments Operable Unit at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Detailed guidance is provided for the following activities: collection of samples from the impoundments; compressive strength testing of the raw sediments; compressive strength testing of the structurally modified (lime and cement additives) sediments; testing for sediment physical properties and settling rates; testing for sediment dewatering characteristics; testing for radiation activity during the field work; testing for polymer additions that may enhance settling. The work plan additionally provides guidance and examples for the preparation of documents necessary to establish readiness for safe and satisfactory performance of the field activities. An outline for the format requested for a report of these data is also provided

  7. Technical work plan for Surface Impoundments Operable Unit engineering support studies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    This document provides a comprehensive work plan which, when utilized as a data collection guide for field activities, will provide the necessary information required to complete a report on geotechnical properties of the sediments contained in the Surface Impoundments Operable Unit at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Detailed guidance is provided for the following activities: collection of samples from the impoundments; compressive strength testing of the raw sediments; compressive strength testing of the structurally modified (lime and cement additives) sediments; testing for sediment physical properties and settling rates; testing for sediment dewatering characteristics; testing for radiation activity during the field work; testing for polymer additions that may enhance settling. The work plan additionally provides guidance and examples for the preparation of documents necessary to establish readiness for safe and satisfactory performance of the field activities. An outline for the format requested for a report of these data is also provided.

  8. Transport and dispersion of pollutants in surface impoundments: a finite element model

    International Nuclear Information System (INIS)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied

  9. Transport and dispersion of pollutants in surface impoundments: a finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  10. Post-remediation action radiological report for Surface Impoundments C (3539) and D (3540) at the Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1998-12-01

    During August and September 1998, Bechtel Jacobs Company LLC performed a remedial action within Impoundments 3539 and 3540 (Impoundments C and D, respectively) in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision (ROD) for the Surface Impoundments Operable Unit. The remedial action included removal of sediments and 0.1 ft of subimpoundment soil. A post-remedial action radiological survey was conducted to provide data to support the Bethel Valley ROD. Data was obtained from (1) a walkover survey for residual gamma radiation on the base of the impoundments, (2) smear surveys for transferable contamination on remaining riprap, and (3) representative sampling of subimpoundment soils. Walkover surveys identified no locations outside the impoundments with gamma exposure levels greater than three times background levels. Smear surveys detected no removable contamination above release limits as specified in 10 CFR 835, Appendix D. Subimpoundment soil samples quantified low levels of residual contamination

  11. Coal combustion waste management at landfills and surface impoundments 1994-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Elcock, D.; Ranek, N. L.; Environmental Science Division

    2006-09-08

    On May 22, 2000, as required by Congress in its 1980 Amendments to the Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency (EPA) issued a Regulatory Determination on Wastes from the Combustion of Fossil Fuels. On the basis of information contained in its 1999 Report to Congress: Wastes from the Combustion of Fossil Fuels, the EPA concluded that coal combustion wastes (CCWs), also known as coal combustion by-products (CCBs), did not warrant regulation under Subtitle C of RCRA, and it retained the existing hazardous waste exemption for these materials under RCRA Section 3001(b)(3)(C). However, the EPA also determined that national regulations under Subtitle D of RCRA were warranted for CCWs that are disposed of in landfills or surface impoundments. The EPA made this determination in part on the basis of its findings that 'present disposal practices are such that, in 1995, these wastes were being managed in 40 percent to 70 percent of landfills and surface impoundments without reasonable controls in place, particularly in the area of groundwater monitoring; and while there have been substantive improvements in state regulatory programs, we have also identified gaps in State oversight' (EPA 2000). The 1999 Report to Congress (RTC), however, may not have reflected the changes in CCW disposal practices that occurred since the cutoff date (1995) of its database and subsequent developments. The U.S. Department of Energy (DOE) and the EPA discussed this issue and decided to conduct a joint DOE/EPA study to collect new information on the recent CCW management practices by the power industry. It was agreed that such information would provide a perspective on the chronological adoption of control measures in CCW units based on State regulations. A team of experts from the EPA, industry, and DOE (with support from Argonne National Laboratory) was established to develop a mutually acceptable approach for collecting and analyzing data

  12. Influence of lake surface area and total phosphorus on annual bluegill growth in small impoundments of central Georgia

    Science.gov (United States)

    Jennings, Cecil A.; Sundmark, Aaron P.

    2017-01-01

    The relationships between environmental variables and the growth rates of fishes are important and rapidly expanding topics in fisheries ecology. We used an informationtheoretic approach to evaluate the influence of lake surface area and total phosphorus on the age-specific growth rates of Lepomis macrochirus (Bluegill) in 6 small impoundments in central Georgia. We used model averaging to create composite models and determine the relative importance of the variables within each model. Results indicated that surface area was the most important factor in the models predicting growth of Bluegills aged 1–4 years; total phosphorus was also an important predictor for the same age-classes. These results suggest that managers can use water quality and lake morphometry variables to create predictive models specific to their waterbody or region to help develop lake-specific management plans that select for and optimize local-level habitat factors for enhancing Bluegill growth.

  13. Probabilistic risk assessment for the Sandia National Laboratories Technical Area V Liquid Waste Disposal System surface impoundments

    International Nuclear Information System (INIS)

    Dawson, L.A.; Eidson, A.F.

    1996-01-01

    A probabilistic risk assessment was completed for a former radioactive waste disposal site. The site, two unlined surface impoundment, was designed as part of the Liquid Waste Disposal System (LWDS) to receive radioactive effluent from nuclear reactors in Technical Area-V (TA-V) at Sandia National Laboratories/New Mexico (SNL/NM). First, a statistical comparison of site sampling results to natural background, using EPA methods, and a spatial distribution analysis were performed. Risk assessment was conducted with SNL/NM's Probabilistic Risk Evaluation and Characterization Investigation System model. The risk assessment indicated that contamination from several constituents might have been high enough to require remediation. However, further analysis based on expected site closure activities and recent EPA guidance indicated that No Further Action was acceptable

  14. Results of the measurement survey of elevation and environmental media in surface impoundments 3513 (B) and 3524 (A) at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Coe, R.H.C. III; Lawrence, J.D.; Winton, W.

    1998-07-01

    A measurement survey of the elevation and environmental media in impoundments 3513 (B) and 3524 (A) at the Oak Ridge National Laboratory (ORNL) was conducted during April 1998. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of Bechtel Jacobs Company. Measurement activities were conducted at selected locations in order to determine the depth and appearance of the sediment and describe the clay underlying the impoundments prior to remediation. The survey was a follow-up to a previous elevation survey. The survey included the following: collection of sediment/clay cores from selected locations in each impoundment; measurement and documentation of the elevation at the water surface, at the top of sediment, at the top of clay, and at the bottom of each core; visual inspection of each core by a soil scientist to confirm the presence of clay and not material such as fly ash and soda lime compacted over the last 50 years; measurement and documentation of the background beta-gamma radiation level at the time and location of collection of each core, the highest beta-gamma level along the sediment portion of each core, and the highest beta-gamma level along the clay portion of each core; measurement and documentation of the length of the clay and of the sediment portion of each core; photographic documentation of each core; and replacement of each core in the impoundment

  15. Results of the radiological and chemical characterization of surface impoundments 3539 and 3540 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Winton, W.; Dean, R.A.; Coe, R.H. III

    1998-03-01

    A radiological and chemical characterization survey of impoundments 3539 and 3540 at the Oak Ridge National Laboratory (ORNL) was conducted during December 1997. Impoundments 3539 and 3540 are located in the Surface Impoundments Operable Unit (SIOU) of Waste Area Group 1. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of the Department of Energy (DOE) Office of Environmental Restoration. Sampling was conducted in order to quantify the presence of polychlorinated biphenyls (PCBs), Resource Conservation and Recovery Act (RCRA) constituents, and other contaminants of interest in support of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation for the SIOU> The survey included collection of sediment/clay samples, quality control blank water samples and equipment rinsate samples for chemical and radiological analysis. Results show the samples contain traces of various organic, inorganic, and radioactive materials. Of particular interest are PCB values which demonstrate the impoundments are not regulated under the Toxic Substances Control Act

  16. 40 CFR 270.17 - Specific part B information requirements for surface impoundments.

    Science.gov (United States)

    2010-07-01

    ... migration of any hazardous constituents into the ground water or surface water at any future time; (2) The....19 of this chapter; (5) Proposed action leakage rate, with rationale, if required under § 264.222 of..., including the double liner system, leak detection system, cover system, and appurtenances for control of...

  17. Hydrologic effects of impoundments in Sherburne National Wildlife Refuge, Minnesota

    Science.gov (United States)

    Brown, R.G.

    1984-01-01

    The hydrologic effects of proposed impoundments in Sherburne National Wildlife Refuge were found to be insignificant with respect to both ground- and surface-water flow patterns and water quality. Monitoring of water levels in 23 observation wells and of discharge in the St. Francis River during 1980 and 1981 has shown that ground water in the surf icial aquifer responds quickly to areal recharge and subsequently discharges to the St. Francis River. The impoundment of surface water in the refuge was not found to affect water levels in the refuge significantly. The impoundments may affect ground-water-flow systems beneath and adjacent to the impoundments. Quality of ground and surface water was found to be similar except ground water contained higher concentrations of dissolved nitrite plus nitrate nitrogen than surface water. Phytoplankton removed dissolved nitrite plus nitrate nitrogen from surface water. The effects of impoundments on water quality are expected to be minor.

  18. 30 CFR 816.84 - Coal mine waste: Impounding structures.

    Science.gov (United States)

    2010-07-01

    ... control, the probable maximum precipitation of a 6-hour precipitation event, or greater event as specified.... Runoff from areas above the disposal facility or runoff from surface of the facility that may cause...-hour design precipitation event. (e) Impounding structures constructed of or impounding coal mine waste...

  19. Erosion protection of uranium tailings impoundments

    International Nuclear Information System (INIS)

    Walters, W.H.; Skaggs, R.L.; Foley, M.G.; Beedlow, P.A.

    1986-09-01

    Pacific Northwest Laboratory (PNL) prepared this report to assist in the design and review of erosion protection works for decommissioned uranium tailings impoundments. The major causes of erosion over the long-term decommissioning period are from rainfall-runoff (overland flow) and stream channel flooding. The method of protection recommended for the impoundment side slopes and site drainage channels is rock riprap. Combinations of vegetation and rock mulch are recommended for the top surface. The design methods were developed from currently available procedures supplemented by field, laboratory, and mathematical model studies performed by PNL. Guidelines for the placement of riprap, inspection, and maintenance are presented. Other subjects discussed are rock selection and testing, slope stability, and overland erosion modeling

  20. 30 CFR 816.49 - Impoundments.

    Science.gov (United States)

    2010-07-01

    ..., prudent, engineering practices and any design criteria established by the regulatory authority. The... surrounding landowners for agricultural, industrial, recreational, or domestic uses. (6) The impoundment will... safely removed in accordance with current, prudent, engineering practices. Such an impoundment shall be...

  1. Dewatering tailings impoundments : interior drains

    International Nuclear Information System (INIS)

    Charlie, W.A.; Doehring, D.O.; Durnford, D.S.

    1984-01-01

    For the design of a new uranium tailings impoundment in the western United States, it was proposed that an interior drainage system be considered to economically and reliably minimize potential short- and long-term environmental impacts. The objectives were to decrease the effective hydraulic head on the clay liner, to dewater and stabilize the tailings, and to increase the amount of water recycled to the mill. In addition, desaturation of the impoundment would induce capillary pressure (negative porewater pressure), further reducing the potential movement of dissolved pollutants. This paper presents saturated and unsaturated seepage principles and reviews the concept, criteria and design of the various interior drainage systems considered

  2. Microbial communities in flowback water impoundments from hydraulic fracturing for recovery of shale gas.

    Science.gov (United States)

    Murali Mohan, Arvind; Hartsock, Angela; Hammack, Richard W; Vidic, Radisav D; Gregory, Kelvin B

    2013-12-01

    Hydraulic fracturing for natural gas extraction from shale produces waste brine known as flowback that is impounded at the surface prior to reuse and/or disposal. During impoundment, microbial activity can alter the fate of metals including radionuclides, give rise to odorous compounds, and result in biocorrosion that complicates water and waste management and increases production costs. Here, we describe the microbial ecology at multiple depths of three flowback impoundments from the Marcellus shale that were managed differently. 16S rRNA gene clone libraries revealed that bacterial communities in the untreated and biocide-amended impoundments were depth dependent, diverse, and most similar to species within the taxa γ-proteobacteria, α-proteobacteria, δ-proteobacteria, Clostridia, Synergistetes, Thermotogae, Spirochetes, and Bacteroidetes. The bacterial community in the pretreated and aerated impoundment was uniform with depth, less diverse, and most similar to known iodide-oxidizing bacteria in the α-proteobacteria. Archaea were identified only in the untreated and biocide-amended impoundments and were affiliated to the Methanomicrobia class. This is the first study of microbial communities in flowback water impoundments from hydraulic fracturing. The findings expand our knowledge of microbial diversity of an emergent and unexplored environment and may guide the management of flowback impoundments. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. Microbial communities in flowback water impoundments from hydraulic fracturing for recovery of shale gas

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Arvind Murali; Hartsock, Angela; Hammack, Richard W; Vidic, Radisav D; Gregory, Kelvin B

    2013-12-01

    Hydraulic fracturing for natural gas extraction from shale produces waste brine known as flowback that is impounded at the surface prior to reuse and/or disposal. During impoundment, microbial activity can alter the fate of metals including radionuclides, give rise to odorous compounds, and result in biocorrosion that complicates water and waste management and increases production costs. Here, we describe the microbial ecology at multiple depths of three flowback impoundments from the Marcellus shale that were managed differently. 16S rRNA gene clone libraries revealed that bacterial communities in the untreated and biocide-amended impoundments were depth dependent, diverse, and most similar to species within the taxa [gamma]-proteobacteria, [alpha]-proteobacteria, δ-proteobacteria, Clostridia, Synergistetes, Thermotogae, Spirochetes, and Bacteroidetes. The bacterial community in the pretreated and aerated impoundment was uniform with depth, less diverse, and most similar to known iodide-oxidizing bacteria in the [alpha]-proteobacteria. Archaea were identified only in the untreated and biocide-amended impoundments and were affiliated to the Methanomicrobia class. This is the first study of microbial communities in flowback water impoundments from hydraulic fracturing. The findings expand our knowledge of microbial diversity of an emergent and unexplored environment and may guide the management of flowback impoundments.

  4. Wind erosion of waste impoundments in arid climates and mitigation of dust pollution.

    Science.gov (United States)

    Blight, G E

    2008-12-01

    Wind can erode and disperse fine-grained material from an impoundment of mining, industrial or municipal waste that stands above the level of its surroundings. Such dust dispersion can be a serious nuisance as well as a health hazard to inhabitants and animals in nearby settlements. It can also degrade crops, making them less marketable, and pollute soil, surface water and ground water. Wind can seasonally erode waste impoundments in all types of climate, but the erosion intensifies and persists for more of each year as regional aridity increases. As clouds of dust are often observed billowing across the top surfaces of waste impoundments in dry windy weather, there is a common misconception that dust arises from erosion of the top surface of an impoundment, resulting in much effort and money being misspent on top treatments when in fact the sloped sides of the impoundments are the true source of blown dust. This paper offers a brief review of general waste impoundment wind erosion issues and then focuses in more detail on the mechanics of how wind erodes surfaces of waste impoundments. Recommendations are offered for mitigating the effects of wind-eroded dust.

  5. Distribution of aquifers, liquid-waste impoundments, and municipal water-supply sources, Massachusetts

    Science.gov (United States)

    Delaney, David F.; Maevsky, Anthony

    1980-01-01

    Impoundments of liquid waste are potential sources of ground-water contamination in Massachusetts. The map report, at a scale of 1 inch equals 4 miles, shows the idstribution of aquifers and the locations of municipal water-supply sources and known liquid-waste impoundments. Ground water, an important source of municipal water supply, is produced from shallow sand and gravel aquifers that are generally unconfined, less than 200 feet thick, and yield less than 2,000 gallons per minute to individual wells. These aquifers commonly occupy lowlands and stream valleys and are most extensive in eastern Massachusetts. Surface impoundments of liquid waste are commonly located over these aquifers. These impoundments may leak and allow waste to infiltrate underlying aquifers and alter their water quality. (USGS)

  6. Rehabilitation of uranium tailings impoundments

    International Nuclear Information System (INIS)

    Crawley, A.H.

    1983-01-01

    Under Australian environmental controls relating to the management of uranium tailings, it is no longer acceptable practice to search for a rehabilitation strategy at the end of production when the generation of tailings has ceased. The uranium projects currently in production and those being proposed are tightly regulated by the authorities. The waste management plans must consider site specific factors and must include selection of appropriate disposal sites and design for long term containment. The final encapsulation in engineered facilities must take into account the probable routes to the environment of the tailings. Rehabilitation shoud be undertaken by the mining and milling operators to standards approved by appropriate authorities. Appropriate administrative arrangements are required, by way of technical committees and financial bonds to ensure that agreed standards of rehabilitation may be achieved. Past and present experience with the rehabilitation of uranium tailings impoundments in Australia is discussed

  7. 49 CFR 193.2181 - Impoundment capacity: LNG storage tanks.

    Science.gov (United States)

    2010-10-01

    ... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Design Impoundment Design and Capacity § 193.2181 Impoundment capacity: LNG storage tanks. Each impounding system serving an LNG storage tank must have a... 49 Transportation 3 2010-10-01 2010-10-01 false Impoundment capacity: LNG storage tanks. 193.2181...

  8. 50 CFR 28.42 - Impounding of domestic animals.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Impounding of domestic animals. 28.42... VIOLATIONS OF PARTS 25, 26, AND 27 Impoundment Procedures § 28.42 Impounding of domestic animals. (a) Any animal trespassing on the lands of any national wildlife refuge may be impounded and disposed of in...

  9. 30 CFR 817.84 - Coal mine waste: Impounding structures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal mine waste: Impounding structures. 817.84... ACTIVITIES § 817.84 Coal mine waste: Impounding structures. New and existing impounding structures constructed of coal mine waste or intended to impound coal mine waste shall meet the requirements of § 817.81...

  10. Design, permitting, and construction issues associated with closure of the Panna Maria uranium tailings impoundment

    International Nuclear Information System (INIS)

    Strachan, C.L.; Raabe, K.L.

    1997-01-01

    In 1992, Panna Maria Uranium Operations (PMUO) initiated licensing and engineering activities for closure of the Panna Maria mill and 150-acre tailings impoundment located in southeast Texas. Closure of the tailings impoundment is permitted by license amendment through the Texas Natural Resources Conservation Commission (TNRCC), and based on closure criteria outlined in Texas regulations. The closure plan for the Panna Maria tailings impoundment was submitted for Texas regulatory agency review in April 1993, with details of the closure plan modified in 1994, 1995, and 1996. The closure plan included a multi-layered cover over the regraded tailings surface which was designed for long-term isolation of tailings, reduction of radon emanation to regulated levels, and reduction of infiltration to TNRCC-accepted levels. The cover and embankment slope surfaces and surrounding areas were designed to provide acceptable erosional stability as compared to runoff velocities from the Probable Maximum Precipitation event. Cover materials were selected from on-site materials and evaluated for suitability based on permeability, radon attenuation, and soil dispersivity characteristics. Off-site materials were used when necessary. The cover over the tailings has a maximum slope of 0.5 percent, and the regraded embankment slopes outside the perimeter of the impoundment have a maximum slope of 20 percent. All reclaimed slopes are covered with topsoil and revegetated. A riprap-lined channel is to be used to convey runoff from within the perimeter of the reclaimed impoundment to the north of the impoundment

  11. Effects of seasonal drawdowns on fish assemblages in sections of an impounded river-canal system in upstate New York

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.; Wells, Scott M

    2016-01-01

    The Mohawk River and New York State Barge Canal run together as a series of permanent and temporary impoundments for most of the distance between Rome and Albany, New York. The downstream or lower section is composed of two permanent impoundments, the middle section of a series of temporary (seasonal) impoundments, and the upper section of a series of permanent impoundments. In the middle section, movable dams are lifted from the water during winter and the wetted surface area decreases by 36–56%. We used boat electrofishing during spring 2014 and 2015 to compare the relative abundance of fish populations and the composition of fish assemblages between the permanently and seasonally impounded sections of the Barge Canal and to infer the effects of the two flow management practices. A total of 3,264 individuals from 38 species were captured, and total catch per unit effort (CPUE) ranged from 46.0 to 134.7 fish/h at sites in the seasonally impounded section, compared with 140.0–342.0 fish/h in the permanent lower section and 89.0–282.0 fish/h in the permanent upper section. The amount of drawdown explained 55% of the variation in total CPUE and was a highly significant predictor variable. Mean total CPUE in the seasonally impounded section was significantly lower (by about 50%) than that in either permanently impounded section, and the assemblage composition differed significantly between sections. The relative abundance of many lentic species was markedly lower in the seasonally impounded section, while the relative abundance of several native cyprinids and the percentage of individuals belonging to species that are native to the watershed was greater in this section. Overall, these findings suggest that winter dam removal in impounded rivers may reduce the abundance of fish but may also create more natural riverine conditions that favor some native species.

  12. Methodologies for evaluating long-term stabilization designs of uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Nelson, J.D.; Abt, S.R.; Volpe, R.L.; Van Zye, D.; Hinkle, N.E.; Staub, W.P.

    1986-06-01

    Uranium mill tailings impoundments require long-term (200 to 1000 years) stabilization. This report reviews currently available methodologies for evaluating factors that can have a significant influence on tailings stabilization and develops methodologies in technical areas where none presently exist. Mill operators can use these methodologies to assist with (1) the selection of sites for mill tailings impoundments, (2) the design of stable impoundments, and (3) the development of reclamation plans for existing impoundments. These methodologies would also be useful for regulatory agency evaluations of proposals in permit or license applications. Methodologies were reviewed or developed in the following technical areas: (1) prediction of the Probable Maximum Precipitation (PMP) and an accompanying Probable Maximum Flood (PMF); (2) prediction of the stability of local and regional fluvial systems; (3) design of impoundment surfaces resistant to gully erosion; (4) evaluation of the potential for surface sheet erosion; (5) design of riprap for protecting embankments from channel flood flow and overland flow; (6) selection of riprap with appropriate durability for its intended use; and (7) evaluation of oversizing required for marginal quality riprap

  13. Effects of rock riprap design parameters on flood protection costs for uranium tailings impoundments

    International Nuclear Information System (INIS)

    Ecker, R.M.

    1984-07-01

    The Pacific Northwest Laboratory (PNL) is studying the problem of long-term protection of earthen covers on decommissioned uranium tailings impoundments. The major erosive forces acting on these covers will be river flooding and overland flow from rainfall-runoff. For impoundments adjacent to rivers, overbank flooding presents the greater potential for significant erosion. To protect the earthen covers against flood erosion, rock riprap armoring will be placed over the cover surface. Because of the large size rock usually required for riprap, the quarrying, transport, and placement of the rock could be a significant part of the decommissioning cost. This report examines the sensitivity of riprap protection costs to certain design parameters at tailings impoundments. The parameters include flood discharge, riprap materials, impoundment side slopes, and an added safety factor. Two decommissioned tailings impoundments are used as case studies for the evaluation. These are the Grand Junction, Colorado, impoundment located adjacent to the Colorado River and the Slickrock, Colorado, impoundment located adjacent to the Dolores River. The evaluation considers only the cost of riprap protection against flood erosion. The study results show that embankment side slope and rock specific gravity can have optimum values or ranges at a specific site. For both case study sites the optimum side slope is about 5H:1V. Of the rock sources considered at Grand Junction, the optimum specific gravity would be about 2.50; however, an optimum rock specific gravity for the Slickrock site could not be determined. Other results indicate that the arbitrary safety factor usually added in riprap design can lead to large increases in protection costs. 22 references, 19 figures, 15 tables

  14. Characterization plan for the waste holding basin (3513 impoundment)

    International Nuclear Information System (INIS)

    Stansfield, R.G.; Francis, C.W.

    1986-09-01

    US Department of Energy (DOE) facilities are required to comply fully with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established the remedial action program, to provide comprehensive management of areas where past research, development, and waste management activities have been conducted and have resulted in residual contamination of facilities or the environment. One of the objectives of this program is to define the extent of contamination at these sites. The intent is to document the known environmental characteristics of the sites and identify the additional actions, such as sampling, analytical measurements, and modeling, necessary to confirm contamination and the possible migration of contaminants from the sites. One of these sites is the waste holding basin (3513 impoundment). The 3513 impoundment is an unlined waste settling basin constructed in 1944 for collection of ORNL wastewater before its discharge into White Oak Creek. Operation of the facility ceased in 1976 when a new process waste treatment plant came into operation. Considerable site-specific environmental information has been developed over the years relative to the type and quantities of radionuclides and hazardous substances contained in the pond water and sediment. The concentrations and patterns of distribution for many of the radionuclides in the aquatic biota as well as for the terrestrial plants growing on the berm of the impoundment have been determined by DOE ecological studies. Recently, some data were collected that evaluate the extent of contaminant movement to the groundwater. Results from these studies are summarized in this report. Also included in this report is an outline of additional tasks needed to obtain the necessary information to model the transport and dose pathways of hazardous substances from the site

  15. Protection of uranium tailings impoundments against overland erosion

    International Nuclear Information System (INIS)

    Walters, W.H.; Skaggs, R.L.

    1986-01-01

    This study investigates the problems involved in designing protection methods to prevent erosion of a uranium tailings impoundment cover from rainfall and runoff (overland flow) processes. The study addresses the side slopes and top surface as separate elements. The side slopes are more subject to gully erosion and require absolute protection such as that provided by rock riprap. The flatter top surface needs much less protection (vegetation/rock combinations) but some estimate of erosion rates are needed to compare alternatives. A literature review indicated that, currently, procedures are not available for the design of rock riprap to prevent gully erosion. Therefore, rock protection on the side slope will have to be based upon engineering judgment determined by the particular site conditions. The Manning-kinetic equations (velocity and depth of runoff) were investigated as a possible aid to the design of gully erosion protection. Guidelines are suggested for the use of rock riprap to prevent gully erosion. Three mathematical models were used to compute erosion rates for the top surface of a hypothetical tailings impoundment. The results recommend that one or possibly both of the regression models could be used to evaluate preliminary protection designs for the top surface. A physical process simulation model should be used for the final design. 30 refs., 13 figs., 16 tabs

  16. 36 CFR 262.11 - Impounding of dogs.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Impounding of dogs. 262.11... ENFORCEMENT SUPPORT ACTIVITIES Impoundments and Removals § 262.11 Impounding of dogs. Any dog found running at large in a part of the National Forest System, which has been closed to dogs running at large, may be...

  17. 30 CFR 817.49 - Impoundments.

    Science.gov (United States)

    2010-07-01

    ... runoff from the design precipitation event when it is demonstrated by the operator and certified by a... constructed to safely pass the applicable design precipitation event specified in paragraph (a)(9)(ii) of this... this section, the required design precipitation event for an impoundment meeting the spillway...

  18. UAV Remote Sensing Surveillance of a Mine Tailings Impoundment in Sub-Arctic Conditions

    Directory of Open Access Journals (Sweden)

    Anssi Rauhala

    2017-12-01

    Full Text Available Mining typically involves extensive areas where environmental monitoring is spatially sporadic. New remote sensing techniques and platforms such as Structure from Motion (SfM and unmanned aerial vehicles (UAVs may offer one solution for more comprehensive and spatially continuous measurements. We conducted UAV campaigns in three consecutive summers (2015–2017 at a sub-Arctic mining site where production was temporarily suspended. The aim was to monitor a 0.5 km2 tailings impoundment and measure potential subsidence of tailings. SfM photogrammetry was used to produce yearly topographical models of the tailings surface, which allowed the amount of surface displacement between years to be tracked. Ground checkpoints surveyed in stable areas of the impoundment were utilized in assessing the vertical accuracy of the models. Observed surface displacements were linked to a combination of erosion, tailings settlement, and possible compaction of the peat layer underlying the tailings. The accuracy obtained indicated that UAV-assisted monitoring of tailings impoundments is sufficiently accurate for supporting impoundment management operations and for tracking surface displacements in the decimeter range.

  19. EM Task 12 - Laser cleaning of Contaminated Painted Surfaces

    International Nuclear Information System (INIS)

    Ames A. Grisanti; Charlene R. Crocker; Robert J. Jensen

    1998-01-01

    Several techniques are available or under development for surface decontamination in nuclear facilities. Each technique has its merits; however, none of them is universally the best choice for all surface decontamination applications. Because of the multitude of factors which influence the environmental and economic aspects of selecting a surface decontamination technique, it is difficult to select the best method in a given situation; an objective basis for comparing techniques is needed. The objective of this project is to develop a software tool for use by personnel selecting a surface decontamination technique. The software will incorporate performance data for available surface decontamination techniques. The beta release of the Surface Decontamination Assistant Software has been completed and has undergone testing at the Energy and Environmental Research Center (EERC). Minor modifications to the software will be completed before the end of November 1998, and a final release of the software will be issued

  20. EM Task 12 - Laser cleaning of contaminated painted surfaces

    International Nuclear Information System (INIS)

    Grisanti, Ames A.; Crocker, Charlene R.; Jensen, Robert R.

    1999-01-01

    Several techniques are available or under development for surface decontamination in nuclear facilities. Each technique has its merits; however, none of them is universally the best choice for all surface decontamination applications. Because of the multitude of factors which influence the environmental and economic aspects of selecting a surface decontamination technique, it is difficult to select the best method in a given situation; an objective basis for comparing techniques is needed. The objective of this project was to develop a software tool for use by personnel selecting a surface decontamination technique. The software incorporates performance data for available surface decontamination techniques. The beta release version of the Surface Decontamination Assistant Software has been completed and has undergone testing at the Energy and Environmental Research Center. Minor modifications to the software were completed, and a final release version of the software is ready to be issued

  1. Distribution and migration of pesticide residues in mosquito control impoundments St. Lucie County, Florida, USA

    Science.gov (United States)

    Parkinson, R. W.; Wang, T. C.; White, J. R.; David, J. R.; Hoffman, M. E.

    1993-09-01

    This project was designed to: (1) document the distribution and migration of organochlorine pesticide residues within marsh substrates of 18 St. Lucie County mosquito control impoundments located along the Indian River Lagoon estuary, and (2) evaluate the impact of water management techniques on residue mobility. Our results indicate that detectible concentrations of organochlorine compounds, applied between the late 1940s and early 1950s, are present in 16 of the 18 St. Lucie County mosquito control impoundments. These compounds are primarily restricted to the surficial, organic-rich wetland sediment, which, based upon geotechnical analysis, was exposed to the atmosphere at a time when the impoundments were subjected to pesticide treatment. Contaminated sediments are present below the surficial, organic-rich layer, suggesting that some vertical migration of pesticides has occurred. It is unlikely that leaching associated with the downward percolation of impounded water was responsible for this migration as pesticide residues were never detected within the in situ pore waters. An alternative explanation is that biological processes (e.g., rooting, burrowing) facilitated the downward flux of organochlorine compounds into sediment horizons not subjected to direct treatment. Eighty-eight surface water samples obtained from two impoundments subjected to contrasting water management techniques were analyzed for pesticide content. None of the surficial water samples collected in association with these impoundments contained detectible concentrations of organochlorine compounds. These samples were unfiltered and contained as much as 25 mg/1 of particulate organic matter. This suggests that the currently preferred management technique (RIM), which is designed to maintain water quality, limit mosquito production, and provide for ecological continuity, does not hydraulically mobilize pesticide residues into the Indian River Lagoon estuary.

  2. The Role of Small Impoundments on Flow Alteration Within River Networks

    Science.gov (United States)

    Brogan, C. O.; Keys, T.; Scott, D.; Burgholzer, R.; Kleiner, J.

    2017-12-01

    Numerous water quality and quantity models have been established to illustrate the ecologic and hydrologic effects of large reservoirs. Smaller, unregulated ponds are often assumed to have a negligible impact on watershed flow regimes even though they overwhelmingly outnumber larger waterbodies. Individually, these small impoundments impart merely a fraction of the flow alteration larger reservoirs do; however, a network of ponds may act cumulatively to alter the flow regime. Many models have attempted to study smaller impoundments but rely on selectively available rating curves or bathymetry surveys. This study created a generalized process to model impoundments of varying size across a 58 square mile watershed exclusively using satellite imagery and publicly available information as inputs. With information drawn from public Army Corps of Engineers databases and LiDAR surveys, it was found that impoundment surface and drainage area served as useful explanatory variables, capable of predicting both pond bathymetry and outlet structure area across the 37 waterbodies modeled within the study area. Working within a flow routing model with inputs from the Chesapeake Bay HSPF model and verified with USGS gauge data, flow simulations were conducted with increasing number of impoundments to quantify how small ponds affect the overall flow regime. As the total impounded volume increased, simulations showed a notable reduction in both low and peak flows. Medium-sized floods increased as the network of ponds and reservoirs stabilized the catchment's streamflow. The results of this study illustrate the importance of including ponded waters into river corridor models to improve downstream management of both water quantity and quality.

  3. Evaluation of Co and Cr mobility in soil profiles collected in a scrapyard of impounded vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Camila N.; Figueiredo, Ana Maria G., E-mail: clange@usp.br, E-mail: anamaria@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Enzweiler, Jacinta, E-mail: jacinta@ige.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Geociencias

    2015-07-01

    The number of motor vehicles in urban environments has increased dramatically in the past years. As a result, so has the number of impounded and end-of-life vehicles. Car wastes can have a very high metal content, which can cause important environmental impacts to the soil where these vehicles are kept. Most Brazilian vehicle impound scrapyards are currently operating at their maximum capacity and soils may have become contaminated by past or current vehicle handling practices. Most of these areas do not present an impermeable surface. The level of soil contamination with heavy metals depends on the type of soil, climate and management practices. Metals, such as Co and Cr, that are present in many auto-parts, may be considered potentially toxic elements in these areas. The aim of this study was to evaluate Co and Cr levels and behavior in soil profiles located in a scrapyard of impounded vehicles of Ribeirao Pires-SP city. For this purpose, samples from distinct horizons of three soil profiles were collected. Element concentrations were determined by Instrumental Neutron Activation Analysis (INAA). Soil parameters such as pH, organic matter content and clay, silt and sand percentage were also determined. The obtained data were statistically analyzed in order to establish correlations between elemental concentrations and the impounded vehicles scrapyard soil. Soil acidity showed to be the most remarkable property for Cr and Co mobility through soil profile. (author)

  4. Evaluation of Co and Cr mobility in soil profiles collected in a scrapyard of impounded vehicles

    International Nuclear Information System (INIS)

    Lange, Camila N.; Figueiredo, Ana Maria G.; Enzweiler, Jacinta

    2015-01-01

    The number of motor vehicles in urban environments has increased dramatically in the past years. As a result, so has the number of impounded and end-of-life vehicles. Car wastes can have a very high metal content, which can cause important environmental impacts to the soil where these vehicles are kept. Most Brazilian vehicle impound scrapyards are currently operating at their maximum capacity and soils may have become contaminated by past or current vehicle handling practices. Most of these areas do not present an impermeable surface. The level of soil contamination with heavy metals depends on the type of soil, climate and management practices. Metals, such as Co and Cr, that are present in many auto-parts, may be considered potentially toxic elements in these areas. The aim of this study was to evaluate Co and Cr levels and behavior in soil profiles located in a scrapyard of impounded vehicles of Ribeirao Pires-SP city. For this purpose, samples from distinct horizons of three soil profiles were collected. Element concentrations were determined by Instrumental Neutron Activation Analysis (INAA). Soil parameters such as pH, organic matter content and clay, silt and sand percentage were also determined. The obtained data were statistically analyzed in order to establish correlations between elemental concentrations and the impounded vehicles scrapyard soil. Soil acidity showed to be the most remarkable property for Cr and Co mobility through soil profile. (author)

  5. Design and construction of an impoundment for precious metal mill tailings

    International Nuclear Information System (INIS)

    Moldt, S.F.; Miller, R.G.; Johnson, K.

    1985-01-01

    An engineering study and design of impoundments for the disposal of mill tailings is presented. The site is located in central Nevada, and the mill will incorporate conventional flotation followed by a carbon-in-pulp cyanide process for extraction of gold from ore. Mill process waste will be generated as flotation tailings and cyanide residue. Permeable site soils and environmental considerations required the prevention of infiltration of cyanide residue leachate into the subgrade. Geochemical modeling of flotation tailings indicated the potential for high concentration of iron and nickel to be present in the flotation tailings leachate. On-site soils were optimized for use in construction of the separate flotation tailings and cyanide residue impoundments. Embankments were constructed on compacted on-site sandy gravels. The cyanide residue impoundment was designed using a four-layer liner, utilizing all on-site soils and chemical soil additives. The liner consists of a leachate collection system over a low-permeability layer, which in turn is underlain by a leak detection drainage blanket and a low permeability subliner. The geochemical modeling performed in the analysis indicated that placement of a thin layer of oxidized surface soils, high in soluble sulfates, on the bottom of the flotation tailings impoundment would be sufficient to react with tailings leachate and cause precipitation of ferric oxide and the associated removal of nickel, permitting flotation tailings leachate to dilute acceptably with natural groundwater

  6. Application of carbon isotopes to detect seepage out of coalbed natural gas produced water impoundments

    International Nuclear Information System (INIS)

    Sharma, Shikha; Baggett, Joshua K.

    2011-01-01

    Highlights: → Coalbed natural gas extraction results in large amount of produced water. → Risk of deterioration of ambient water quality. → Carbon isotope natural tracer for detecting seepage from produced water impoundments. - Abstract: Coalbed natural gas (CBNG) production from coal bed aquifers requires large volumes of produced water to be pumped from the subsurface. The produced water ranges from high quality that meets state and federal drinking water standards to low quality due to increased salinity and/or sodicity. The Powder River Basin of northeastern Wyoming is a major coalbed natural gas producing region, where water quality generally decreases moving from the southeastern portion of the basin towards the center. Most produced water in Wyoming is disposed into impoundments and other surface drainages, where it may infiltrate into shallow groundwater. Groundwater degradation caused by infiltration of CBNG produced water holding impoundments into arid, soluble salt-rich soils is an issue of immense importance because groundwater is a major source for stock water, irrigation, and drinking water for many small communities in these areas. This study examines the potential of using stable C isotope signatures of dissolved inorganic C (δ 13 C DIC ) to track the fate of CBNG produced water after it is discharged into the impoundments. Other geochemical proxies like the major cations and major anions were used in conjunction with field water quality measurements to understand the geochemical differences between CBNG produced waters and ambient waters in the study area. Samples were collected from the CBNG discharge outfalls, produced water holding impoundments, and monitoring wells from different parts of the Powder River Basin and analyzed for δ 13 C DIC . The CBNG produced waters from outfalls and impoundments have positive δ 13 C DIC values that fall within the range of +12 per mille to +22 per mille, distinct from the ambient regional surface and

  7. A dual phosphorylation switch controls 14-3-3-dependent cell surface expression of TASK-1

    Science.gov (United States)

    Kilisch, Markus; Lytovchenko, Olga; Arakel, Eric C.; Bertinetti, Daniela; Schwappach, Blanche

    2016-01-01

    ABSTRACT The transport of the K+ channels TASK-1 and TASK-3 (also known as KCNK3 and KCNK9, respectively) to the cell surface is controlled by the binding of 14-3-3 proteins to a trafficking control region at the extreme C-terminus of the channels. The current model proposes that phosphorylation-dependent binding of 14-3-3 sterically masks a COPI-binding motif. However, the direct effects of phosphorylation on COPI binding and on the binding parameters of 14-3-3 isoforms are still unknown. We find that phosphorylation of the trafficking control region prevents COPI binding even in the absence of 14-3-3, and we present a quantitative analysis of the binding of all human 14-3-3 isoforms to the trafficking control regions of TASK-1 and TASK-3. Surprisingly, the affinities of 14-3-3 proteins for TASK-1 are two orders of magnitude lower than for TASK-3. Furthermore, we find that phosphorylation of a second serine residue in the C-terminus of TASK-1 inhibits 14-3-3 binding. Thus, phosphorylation of the trafficking control region can stimulate or inhibit transport of TASK-1 to the cell surface depending on the target serine residue. Our findings indicate that control of TASK-1 trafficking by COPI, kinases, phosphatases and 14-3-3 proteins is highly dynamic. PMID:26743085

  8. Responsiveness summary for the engineering evaluation/cost analysis for the proposed management of contaminated water impounded at the Weldon Spring Chemical Plant Area

    International Nuclear Information System (INIS)

    Maxey, M.L.; MacDonell, M.M.; Peterson, J.M.

    1991-01-01

    The US Department of Energy (DOE) issued the Engineering Evaluation/Cost Analysis for the Proposed Management of Contaminated Water Impounded at the Weldon Spring Chemical Plant Area in July 1990. The engineering evaluation/cost analysis (EE/CA) examines various alternatives for the proposed action to manage contaminated surface water impounded at the chemical plant area. The primary objective is to minimize potential migration of contaminants from surface impoundments to the local environment. The EE/CA addresses water currently impounded in four waste raffinate pits and two small ponds and water that will be impounded in the future as a result of upcoming response actions. Radioactive and chemical contaminants are migrating from the currently impounded water to underlying on-site groundwater via seepage and to off-site surface water via runoff. The treatment process and facilities that will be provided for management of currently impounded water can subsequently be used to manage other contaminated water in the future. Based on the evaluation of various alternatives in the EE/CA, DOE determined that the best approach for managing surface water impounded at the chemical plant area would be to remove contaminants from the water and release the treatment water to the Missouri River via a natural drainage channel. To establish requirements for releasing this treated water, DOE applied for a modification to its existing discharge permit from the Missouri Department of Natural Resources (DNR) under the National Pollutant Discharge Elimination System (NPDES) program. The EE/CA provided a major source of technical input to the application for modifying the permit. This responsiveness summary has been prepared to address the major issues identified in oral and written comments on the proposed action. 1 tab

  9. Surface feature congruency effects in the object-reviewing paradigm are dependent on task memory demands.

    Science.gov (United States)

    Kimchi, Ruth; Pirkner, Yossef

    2014-08-01

    Perception of object continuity depends on establishing correspondence between objects viewed across disruptions in visual information. The role of spatiotemporal information in guiding object continuity is well documented; the role of surface features, however, is controversial. Some researchers have shown an object-specific preview benefit (OSPB)-a standard index of object continuity-only when correspondence could be based on an object's spatiotemporal information, whereas others have found color-based OSPB, suggesting that surface features can also guide object continuity. This study shows that surface feature-based OSPB is dependent on the task memory demands. When the task involved letters and matching just one target letter to the preview ones, no color congruency effect was found under spatiotemporal discontinuity and spatiotemporal ambiguity (Experiments 1-3), indicating that the absence of feature-based OSPB cannot be accounted for by salient spatiotemporal discontinuity. When the task involved complex shapes and matching two target shapes to the preview ones, color-based OSPB was obtained. Critically, however, when a visual working memory task was performed concurrently with the matching task, the presence of a nonspatial (but not a spatial) working memory load eliminated the color-based OSPB (Experiments 4 and 5). These results suggest that the surface feature congruency effects that are observed in the object-reviewing paradigm (with the matching task) reflect memory-based strategies that participants use to solve a memory-demanding task; therefore, they are not reliable measures of online object continuity and cannot be taken as evidence for the role of surface features in establishing object correspondence.

  10. Moist Soil Management of Wetland Impoundments for Plants and Invertebrates

    Data.gov (United States)

    Department of the Interior — In year’s past an impoundment was drained (a drawdown) when floating-leaved plants covered more than 50% of the water area. Drawdowns encourage beneficial moist soil...

  11. 32 CFR 634.51 - Procedures for impoundment.

    Science.gov (United States)

    2010-07-01

    ... complete DD Form 2506 (Vehicle Impoundment Report) as a record of the actions taken. (i) An inventory... not be inventoried. Such articles should be opened only if necessary to identify the owner of the...

  12. Characterization and assessment of potential environmental risk of tailings stored in seven impoundments in the Aries river basin, Western Romania

    Science.gov (United States)

    2013-01-01

    Background The objective of this study was to examine the potential environmental risk of tailings resulted after precious and base metal ores processing, stored in seven impoundments located in the Aries river basin, Romania. The tailings were characterized by mineralogical and elemental composition, contamination indices, acid rock drainage generation potential and water leachability of hazardous/priority hazardous metals and ions. Multivariate statistical methods were used for data interpretation. Results Tailings were found to be highly contaminated with several hazardous/priority hazardous metals (As, Cu, Cd, Pb), and pose potential contamination risk for soil, sediments, surface and groundwater. Two out of the seven studied impoundments does not satisfy the criteria required for inert wastes, shows acid rock drainage potential and thus can contaminate the surface and groundwater. Three impoundments were found to be highly contaminated with As, Pb and Cd, two with As and other two with Cu. The tailings impoundments were grouped based on the enrichment factor, geoaccumulation index, contamination factor and contamination degree of 7 hazardous/priority hazardous metals (As, Cd, Cr, Cu, Ni, Pb, Zn) considered typical for the studied tailings. Principal component analysis showed that 47% of the elemental variability was attributable to alkaline silicate rocks, 31% to acidic S-containing minerals, 12% to carbonate minerals and 5% to biogenic elements. Leachability of metals and ions was ascribed in proportion of 61% to silicates, 11% to acidic minerals and 6% to the organic matter. A variability of 18% was attributed to leachability of biogenic elements (Na, K, Cl-, NO3-) with no potential environmental risk. Pattern recognition by agglomerative hierarchical clustering emphasized the grouping of impoundments in agreement with their contamination degree and acid rock drainage generation potential. Conclusions Tailings stored in the studied impoundments were found to

  13. Characterization and assessment of potential environmental risk of tailings stored in seven impoundments in the Aries river basin, Western Romania

    Directory of Open Access Journals (Sweden)

    Levei Erika

    2013-01-01

    Full Text Available Abstract Background The objective of this study was to examine the potential environmental risk of tailings resulted after precious and base metal ores processing, stored in seven impoundments located in the Aries river basin, Romania. The tailings were characterized by mineralogical and elemental composition, contamination indices, acid rock drainage generation potential and water leachability of hazardous/priority hazardous metals and ions. Multivariate statistical methods were used for data interpretation. Results Tailings were found to be highly contaminated with several hazardous/priority hazardous metals (As, Cu, Cd, Pb, and pose potential contamination risk for soil, sediments, surface and groundwater. Two out of the seven studied impoundments does not satisfy the criteria required for inert wastes, shows acid rock drainage potential and thus can contaminate the surface and groundwater. Three impoundments were found to be highly contaminated with As, Pb and Cd, two with As and other two with Cu. The tailings impoundments were grouped based on the enrichment factor, geoaccumulation index, contamination factor and contamination degree of 7 hazardous/priority hazardous metals (As, Cd, Cr, Cu, Ni, Pb, Zn considered typical for the studied tailings. Principal component analysis showed that 47% of the elemental variability was attributable to alkaline silicate rocks, 31% to acidic S-containing minerals, 12% to carbonate minerals and 5% to biogenic elements. Leachability of metals and ions was ascribed in proportion of 61% to silicates, 11% to acidic minerals and 6% to the organic matter. A variability of 18% was attributed to leachability of biogenic elements (Na, K, Cl-, NO3- with no potential environmental risk. Pattern recognition by agglomerative hierarchical clustering emphasized the grouping of impoundments in agreement with their contamination degree and acid rock drainage generation potential. Conclusions Tailings stored in the studied

  14. Visual Information and Support Surface for Postural Control in Visual Search Task.

    Science.gov (United States)

    Huang, Chia-Chun; Yang, Chih-Mei

    2016-10-01

    When standing on a reduced support surface, people increase their reliance on visual information to control posture. This assertion was tested in the current study. The effects of imposed motion and support surface on postural control during visual search were investigated. Twelve participants (aged 21 ± 1.8 years; six men and six women) stood on a reduced support surface (45% base of support). In a room that moved back and forth along the anteroposterior axis, participants performed visual search for a given letter in an article. Postural sway variability and head-room coupling were measured. The results of head-room coupling, but not postural sway, supported the assertion that people increase reliance on visual information when standing on a reduced support surface. Whether standing on a whole or reduced surface, people stabilized their posture to perform the visual search tasks. Compared to a fixed target, searching on a hand-held target showed greater head-room coupling when standing on a reduced surface. © The Author(s) 2016.

  15. French Modular Impoundment: Final Cost and Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Drown, Peter [French Development Enterprises, LLC, North Billerica, MA (United States); French, Bill [French Development Enterprises, LLC, North Billerica, MA (United States)

    2017-05-17

    This report comprises the Final Cost and Performance Report for the Department of Energy Award # EE0007244, the French Modular Impoundment (aka the “French Dam”.) The French Dam is a system of applying precast modular construction to water control structures. The “French Dam” is a term used to cover the construction means/methods used to construct or rehabilitate dams, diversion structures, powerhouses, and other hydraulic structures which impound water and are covered under FDE’s existing IP (Patents # US8414223B2; US9103084B2.)

  16. Simulated effects of impoundment of lake seminole on ground-water flow in the upper Floridan Aquifer in southwestern Georgia and adjacent parts of Alabama and Florida

    Science.gov (United States)

    Jones, L. Elliott; Torak, Lynn J.

    2004-01-01

    Hydrologic implications of the impoundment of Lake Seminole in southwest Georgia and its effect on components of the surface- and ground-water flow systems of the lower Apalachicola?Chattahoochee?Flint (ACF) River Basin were investigated using a ground-water model. Comparison of simulation results of postimpoundment drought conditions (October 1986) with results of hypothetical preimpoundment conditions (a similar drought prior to 1955) provides a qualitative measure of the changes in hydraulic head and ground-water flow to and from streams and Lake Seminole, and across State lines caused by the impoundment. Based on the simulation results, the impoundment of Lake Seminole changed ground-water flow directions within about 20?30 miles of the lake, reducing the amount of ground water flowing from Florida to Georgia southeast of the lake. Ground-water storage was increased by the impoundment, as indicated by a simulated increase of as much as 26 feet in the water level in the Upper Floridan aquifer. The impoundment of Lake Seminole caused changes to simulated components of the ground-water budget, including reduced discharge from the Upper Floridan aquifer to streams (315 million gallons per day); reduced recharge from or increased discharge to regional ground-water flow at external model boundaries (totaling 183 million gallons per day); and reduced recharge from or increased discharge to the undifferentiated overburden (totaling 129 million gallons per day).

  17. Effect of weir impoundments on methane dynamics in a river

    Czech Academy of Sciences Publication Activity Database

    Bednařík, A.; Blaser, M.; Matoušů, Anna; Hekera, P.; Rulík, M.

    2017-01-01

    Roč. 584, April (2017), s. 164-174 ISSN 0048-9697 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : methane production * methane emission * methane ebullition * river impoundment * river sediment Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 4.900, year: 2016

  18. Acidity of Lakes and Impoundments in North-Central Minnesota

    Science.gov (United States)

    Elon S. Verry

    1981-01-01

    Measurements of lake and impoundment pH for several years, intensive sampling within years, and pH-calcium plots verify normal pH levels and do not show evidence of changes due to acid precipitation. These data in comparison with general lake data narrow the northern Lake States area in which rain or snow may cause lake acidification.

  19. Optimization of restricted ROC surfaces in three-class classification tasks.

    Science.gov (United States)

    Edwards, Darrin C; Metz, Charles E

    2007-10-01

    We have shown previously that an N-class ideal observer achieves the optimal receiver operating characteristic (ROC) hypersurface in a Neyman-Pearson sense. Due to the inherent complexity of evaluating observer performance even in a three-class classification task, some researchers have suggested a generally incomplete but more tractable evaluation in terms of a surface, plotting only the three "sensitivities." More generally, one can evaluate observer performance with a single sensitivity or misclassification probability as a function of two linear combinations of sensitivities or misclassification probabilities. We analyzed four such formulations including the "sensitivity" surface. In each case, we applied the Neyman-Pearson criterion to find the observer which achieves optimal performance with respect to each given set of "performance description variables" under consideration. In the unrestricted case, optimization with respect to the Neyman-Pearson criterion yields the ideal observer, as does maximization of the observer's expected utility. Moreover, during our consideration of the restricted cases, we found that the two optimization methods do not merely yield the same observer, but are in fact completely equivalent in a mathematical sense. Thus, for a wide variety of observers which maximize performance with respect to a restricted ROC surface in the Neyman-Pearson sense, that ROC surface can also be shown to provide a complete description of the observer's performance in an expected utility sense.

  20. 40 CFR 264.1085 - Standards: Surface impoundments.

    Science.gov (United States)

    2010-07-01

    ... materials of construction and designing the cover and closure devices shall include: Organic vapor... closure device in the closed position, as applicable. (B) To remove accumulated sludge or other residues... construction and designing the cover and closure devices shall include: Organic vapor permeability; the effects...

  1. 40 CFR 265.1086 - Standards: Surface impoundments.

    Science.gov (United States)

    2010-07-01

    ... materials of construction and designing the cover and closure devices shall include: Organic vapor... closure device in the closed position, as applicable. (B) To remove accumulated sludge or other residues... construction and designing the cover and closure devices shall include: Organic vapor permeability; the effects...

  2. Interfacial stability of soil covers on lined surface impoundments

    International Nuclear Information System (INIS)

    Mitchell, D.H.; Gates, T.E.

    1986-04-01

    The factors affecting the interfacial stability of soil covers on geomembranes were examined to determine the maximum stable slopes for soil cover/geomembrane systems. Several instances of instability of soil covers on geomembranes have occurred at tailings ponds, leaving exposed geomembranes with the potential for physical ddamage and possibly chemical and ultraviolet degradation. From an operator's viewpoint, it is desirable to maximize the slope of lined facilities in order to maximize the volume-to-area ratio; however, the likelihood for instability also increases with increasing slope. Frictional data obtained from direct shear tests are compared with stability data obtained using a nine-square-meter (m 2 ) engineering-scale test stand to verify that direct shear test data are valid in slope design calculations. Interfacial frictional data from direct shear tests using high-density polyethylene and a poorly graded sand cover agree within several degrees with the engineering-scale tests. Additional tests with other soils and geomembranes are planned. The instability of soil covers is not always an interfacial problem; soil erosion and limited drainage capacity are additional factors that must be considered in the design of covered slopes. 7 refs., 5 figs., 2 tabs

  3. Engineering evaluation/cost analysis for the proposed management of contaminated water impounded at the Weldon Spring chemical plant area

    International Nuclear Information System (INIS)

    MacDonell, M.M.; Maxey, M.L.; Peterson, J.M.; Joya, I.E.

    1990-07-01

    This engineering evaluation/cost analysis (EE/CA) report has been prepared to support the proposed removal action for managing contaminated surface waters impounded at the chemical plant area of the Weldon Spring site, located near Weldon Spring, Missouri. The US Department of Energy is responsible for cleanup activities at the site under its Surplus Facilities Management Program (SFMP). The major goals of SFMP are to eliminate potential hazards to human health and the environment that are associated with contamination at SFMP sites and to make surplus real property available for other uses, to the extent possible. The objectives of this EE/CA report are to identify the cleanup as a removal action, document the selection of a response that will mitigate the potential release of radioactive or chemical contaminants from the impounded waters into the nearby environment, and address environmental impacts associated with the proposed action. 41 refs., 8 figs., 8 tabs

  4. Evaluation of workers' perceived sense of slip and effect of prior knowledge of slipperiness during task performance on slippery surfaces.

    Science.gov (United States)

    Chiou, S; Bhattacharya, A; Succop, P A

    2000-01-01

    Forty healthy industrial workers (age: 41.0+/-14.9 years) were tested for postural stability for three simulated tasks: (1) standing upright; (2) rapid trunk movement; and (3) lateral reach during lifting. These tasks were performed on four levels of slippery surfaces under different environmental lighting with new or workers' own old shoes. Prior to postural stability tests, each subject was given the opportunity to assess the surface slipperiness that he or she would encounter in the subsequent postural stability tests. A perceived sense of slip (PSOS) scale was administrated immediately after each test to determine subjects' PSOS. Subjects' postural sway and instability during task performance was determined by using a strain gauge type force platform. Results from this study indicate that subjects who were cautious in assessing surface slipperiness had less postural instability during task performance. Subjects could perceive the likely slips due to the change in task (p=0.0001) and surface slipperiness (p=0.0001). The PSOS scale is reproducible, easy to use, and provides a simple way to evaluate potential slip hazards in the workplace. Results from this study should aid understanding of the factors critical to maintaining postural stability on slippery surfaces, and will help to develop guidelines for safety training and identify slip hazards in the workplace.

  5. Evaluation of Major Dike-Impounded Ground-Water Reservoirs, Island of Oahu

    Science.gov (United States)

    Takasaki, Kiyoshi J.; Mink, John Francis

    1985-01-01

    Ground-water reservoirs impounded by volcanic dikes receive a substantial part of the total recharge to ground water on the island of Oahu because they generally underlie the rainiest areas. These reservoirs accumulate the infiltration from rainfall, store it temporarily, and steadily leak it to abutting basal reservoirs or to streams cutting into them. The dike reservoirs have high hydraulic heads and are mostly isolated from saline water. The most important and productive of the dike-impounded reservoirs are in an area of about 135 square miles in the main fissure zone of the Koolau volcano where the top of the dike-impounded water reaches an altitude of at least 1,000 feet. Water is impounded and stored both above and below sea level. The water stored above sea level in the 135 square mile area has been roughly estimated at 560 billion gallons. In comparison, the water stored above sea level in reservoirs underlying a dike-intruded area of about 53 square miles in the Waianae Range has been roughly estimated at 100 billion gallons. Storage below sea level is indeterminable, owing to uncertainties about the ability of the rock to store water as dike density increases and porosity decreases. Tunnels, by breaching dike controls, have reduced the water stored above sea level by at least 50 billion gallons in the Koolau Range and by 5 1/2 billion gallons in the Waianae Range, only a small part of the total water stored. Total leakage from storage in the Koolau Range has been estimated at about 280 Mgal/d (million gallons per day). This estimated leakage from the dike-impounded reservoirs makes up a significant part of the ground-water yield of the Koolau Range, which has been estimated to range from 450 to 580 Mgal/d. The largest unused surface leakage is in the Kaneohe, Kahana, and Punaluu areas, and the largest unused underflow occurs in the Waialee, Hauula-Laie, Punaluu, and Kahana areas. The unused underflow leakage is small in areas near and east of Waialae, but

  6. Assessment of sediments in the riverine impoundments of national wildlife refuges in the Souris River Basin, North Dakota

    Science.gov (United States)

    Tangen, Brian A.; Laubhan, Murray K.; Gleason, Robert A.

    2014-01-01

    Accelerated sedimentation of reservoirs and riverine impoundments is a major concern throughout the United States. Sediments not only fill impoundments and reduce their effective life span, but they can reduce water quality by increasing turbidity and introducing harmful chemical constituents such as heavy metals, toxic elements, and nutrients. U.S. Fish and Wildlife Service national wildlife refuges in the north-central part of the United States have documented high amounts of sediment accretion in some wetlands that could negatively affect important aquatic habitats for migratory birds and other wetland-dependent wildlife. Therefore, information pertaining to sediment accumulation in refuge impoundments potentially is important to guide conservation planning, including future management actions of individual impoundments. Lands comprising Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges, collectively known as the Souris River Basin refuges, encompass reaches of the Des Lacs and Souris Rivers of northwestern North Dakota. The riverine impoundments of the Souris River Basin refuges are vulnerable to sedimentation because of the construction of in-stream dams that interrupt and slow river flows and because of post-European settlement land-use changes that have increased the potential for soil erosion and transport to rivers. Information regarding sediments does not exist for these refuges, and U.S. Fish and Wildlife Service personnel have expressed interest in assessing refuge impoundments to support refuge management decisions. Sediment cores and surface sediment samples were collected from impoundments within Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges during 2004–05. Cores were used to estimate sediment accretion rates using radioisotope (cesium-137 [137Cs], lead-210 [210Pb]) dating techniques. Sediment cores and surface samples were analyzed for a suite of elements and agrichemicals, respectively. Examination of

  7. Stochastic Modelling of the Hydraulic Anisotropy of Ash Impoundment Sediment

    Science.gov (United States)

    Slávik, Ivan

    2017-12-01

    In the case reported here the impoundments of a 400 MW coal heated power plant with an annual production of about 1.5 million tons of fuel ash are of the cross-valley type, operated by the simple and cheap „upstream method”. The aim of the research was to determine overall and local values of the permeability in horizontal as well as in vertical direction and the anisotropy of the thin-layered sedimented ash. The coal ashes are hydraulically transported through pipelines in form of a slurry and periodically floated on the beach of the impoundment. The ashes are deposited in the form of a thin-layered sediment, with random alternation of layers with a coarser or finer granularity. The ash impoundment sediment is anthropogenic sediment with horizontally laminated texture. Therefore, the sediment is anisotropic from the viewpoint of water seepage. The knowledge of the permeability and the seepage anisotropy of the sediment is a basic requirement for the design of an appropriate dewatering system. The seepage anisotropy of the ash sediment has been checked by means of stochastic modelling, based on the correlation between the effective grain diameter and the coefficient of permeability of the ash: the effective grain diameter and the thickness of individual layers have been proposed to be random events.

  8. Gully potential in soil-covered uranium waste impoundments

    International Nuclear Information System (INIS)

    Abt, S.R.; Hogan, S.A.; Johnson, T.L.

    1994-01-01

    Soil covers are routinely considered a design alternative to stabilize uranium waste impoundments. Gully intrusion into the cover is one of the greatest potential threats to the long-term stability of an impoundment. An investigation was conducted to estimate the maximum depth of gully intrusion, the approximate top width of the gully at the point of maximum incision, and the approximate location of the maximum intrusion. A large-scale laboratory study was conducted on seven embankments in which approximately 200 years of rainfall was simulated and the resulting gullies were documented. In addition, 11 gullies occurring in actual reclaimed impoundments were documented. An analysis of the laboratory and field data sets was performed in which the maximum depth of gully incision, top width of the gully, and location of the maximum gully incision were related to the pile height, tributary volume of runoff, and soil composition. These relations provide the designers with a means for assessing the cover design to meet the long-term stability of the waste

  9. Investigation, assessment and remediation of the water pathway in the surroundings of the Culmitzsch A tailings impoundment

    International Nuclear Information System (INIS)

    Schulze, G.; Paul, M.; Priester, J.; Schoepfer, C.

    1998-01-01

    Several large tailings impoundments in Saxony and Thuringia are the result of the extensive uranium mining and milling in Eastern Germany after World War II. The Culmitzsch tailings pond in Eastern Thuringia was constructed within a former uranium open pit mine and is located within the Culmitzsch trench fault. The tailings impoundment includes two ponds (Culmitzsch A and B) which are separated by an internal dam with an impervious core. The Culmitzsch A pond covers an area of 158 ha, the maximum tailings thickness is 70 m. Between this pond (elevation of up to 340 m above sea-level) and the Lerchenbach creek (265.. 280 m above sea-level) a steep gradient exists. So the valley of the Lerchenbach is the general discharge area for the seepage of the pond which is a result of dewatering by gravity and consolidation. The seepage water migrates through the southern dam of the impoundment and through permeable layers which are in contact with the tailings. About 400 groundwater wells were installed within three aquifers in order to clarify the flow direction and the degree of contamination of the groundwater as well as to investigate the geohydraulic properties of the rocks in the surroundings of the pond. Based on the results of this investigation programme a three-dimensional hydrogeological model was built up which reflects the general relationships between the pond and its geological setting as well as the water balance of the whole system. Presently a catchment system exists which gathers all surface waters with significant uranium and salt concentrations. Moreover dewatering wells on the beach zone of the pond and catchment wells in the downstream area of the impoundment have been installed. Before being released to the receiving streams seepage and freewater are treated in a two-step water treatment plant in order to decrease their uranium, radium and arsenic contents. (orig.) [de

  10. A task specific uncertainty analysis method for least-squares-based form characterization of ultra-precision freeform surfaces

    International Nuclear Information System (INIS)

    Ren, M J; Cheung, C F; Kong, L B

    2012-01-01

    In the measurement of ultra-precision freeform surfaces, least-squares-based form characterization methods are widely used to evaluate the form error of the measured surfaces. Although many methodologies have been proposed in recent years to improve the efficiency of the characterization process, relatively little research has been conducted on the analysis of associated uncertainty in the characterization results which may result from those characterization methods being used. As a result, this paper presents a task specific uncertainty analysis method with application in the least-squares-based form characterization of ultra-precision freeform surfaces. That is, the associated uncertainty in the form characterization results is estimated when the measured data are extracted from a specific surface with specific sampling strategy. Three factors are considered in this study which include measurement error, surface form error and sample size. The task specific uncertainty analysis method has been evaluated through a series of experiments. The results show that the task specific uncertainty analysis method can effectively estimate the uncertainty of the form characterization results for a specific freeform surface measurement

  11. Run-of-River Impoundments Can Remain Unfilled While Transporting Gravel Bedload: Numerical Modeling Results

    Science.gov (United States)

    Pearson, A.; Pizzuto, J. E.

    2015-12-01

    Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.

  12. Groundwater monitoring at three Oak Ridge National Laboratory inactive waste impoundments: results after one year

    Energy Technology Data Exchange (ETDEWEB)

    Francis, C. W.; Stansfield, R. G.

    1986-10-01

    To determine if the migration of potential contaminants from three inactive waste impoundments at Oak Ridge National Laboratory poses a threat to groundwater quality, at least one upgradient groundwater monitoring well and threee downgradient monitoring wells were installed at each impoundment in early 1985. These three unlined impoundments, formerly used to collect and, in some instances, treat wastewater are: the 3513 impoundment; the Old Hydrofracture Facility (OHF) impoundment; and the Homogeneous Reactor Experimnt No. 2 impoundment. Groundwater samples were collected quarterly for one year. Analyses were conducted for the groundwater protection parameters promulgated by the Resource Conservation and Recovery Act. The groundwater samples were also analyzed for polychlorinated biphenyls, copper, nickel, zinc, /sup 90/Sr, /sup 137/Cs, and tritium. The contaminants found most often to affect groundwater quality at all three waste impoundments were radionuclides. For example, mean concentrations of gross beta and gross alpha activity exceeded drinking water limits at all three sites. The gross beta limit was exceeded at the 3513 and OHF impoundments by either /sup 90/Sr or tritium levels. At the 3513 impoundment, there was substantial evidence that the downgradient groundwater has been contaminated by chromium and lead and possibly by halogenated organic compounds. At the OHF impoundment, the mean level of tritium measured in the upgradient well (about 91,000 Bq/L as compared with 80,000 Bq/L in the downgradient wells) indicated that the groundwater quality has been affected by the radioactive wastes buried in the low-level radioactive waste burial ground solid waste storage area-5 upgradient of the impoundment. Testing for groundwater contamination, disclosed statistically significant contamination at all three sites.

  13. Groundwater monitoring at three Oak Ridge National Laboratory inactive waste impoundments: results after one year

    International Nuclear Information System (INIS)

    Francis, C.W.; Stansfield, R.G.

    1986-10-01

    To determine if the migration of potential contaminants from three inactive waste impoundments at Oak Ridge National Laboratory poses a threat to groundwater quality, at least one upgradient groundwater monitoring well and threee downgradient monitoring wells were installed at each impoundment in early 1985. These three unlined impoundments, formerly used to collect and, in some instances, treat wastewater are: the 3513 impoundment; the Old Hydrofracture Facility (OHF) impoundment; and the Homogeneous Reactor Experimnt No. 2 impoundment. Groundwater samples were collected quarterly for one year. Analyses were conducted for the groundwater protection parameters promulgated by the Resource Conservation and Recovery Act. The groundwater samples were also analyzed for polychlorinated biphenyls, copper, nickel, zinc, 90 Sr, 137 Cs, and tritium. The contaminants found most often to affect groundwater quality at all three waste impoundments were radionuclides. For example, mean concentrations of gross beta and gross alpha activity exceeded drinking water limits at all three sites. The gross beta limit was exceeded at the 3513 and OHF impoundments by either 90 Sr or tritium levels. At the 3513 impoundment, there was substantial evidence that the downgradient groundwater has been contaminated by chromium and lead and possibly by halogenated organic compounds. At the OHF impoundment, the mean level of tritium measured in the upgradient well (about 91,000 Bq/L as compared with 80,000 Bq/L in the downgradient wells) indicated that the groundwater quality has been affected by the radioactive wastes buried in the low-level radioactive waste burial ground solid waste storage area-5 upgradient of the impoundment. Testing for groundwater contamination, disclosed statistically significant contamination at all three sites

  14. Reestablishing the Dominance of Biogeochemical Pathways for Reducing Downstream Nutrient Losses from Aged Impounded Features

    Science.gov (United States)

    Shukla, S.; Shukla, A.

    2017-12-01

    Water and phosphorus (P) dynamics and loss pathways at two stormwater impoundments (SIs) were analyzed using measured fluxes between 2008 and 2011. These SIs are a decade old. Analyses of water and P budgets along with the discernment of various P pools and characterization of the intermediary processes revealed that soil adsorption and plant uptake are secondary to volume reduction apropos of P treatment. At one site, extreme wet conditions in a year combined with soil P saturation resulted in it being a P source rather than a sink. The impoundment (SI-1) discharged 12% more P than incoming due to soil P desorption, a consequence of dilution of incoming stormwater with large water input from an extreme tropical rain event. The second impoundment (SI-2) was a consistent sink of P; 55% and 95% of the incoming total P was retained in the two years, mainly as a result of 49% and 84% volume retention, respectively. Analysis of plant available aluminum, iron, and phosphorus showed the surface soil to be P saturated and at risk of releasing P to a limit of environmental concern. These results when seen in light of more frequent extreme precipitation events under the changed climate scenario call for alternatives to revive the role of biogeochemical processes in P treatment because volume reduction may not always be the viable option, especially for wet conditions. Aboveground biomass harvesting and removal was evaluated to transform the SIs from a frequent P source to sink and maintain the long-term sink functions of the SIs. Use of harvested biomass as a source of nutrients (N and P) and carbon to agricultural soil can result in beneficial use of biomass and offset the cost of harvesting. Other avenues such as altering the hydrology of the SIs by compartmentalizing the system and increasing the storage were also explored for short-term benefits. Results provided a combination of hydraulic and biochemical options for achieving long-term water and nutrient retentions in

  15. 25 CFR 700.727 - Impoundment and disposal of unauthorized livestock.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Impoundment and disposal of unauthorized livestock. 700... RELOCATION PROCEDURES New Lands Grazing § 700.727 Impoundment and disposal of unauthorized livestock. Unauthorized livestock within any range unit of the New Lands which are not removed therefrom within the...

  16. 25 CFR 168.16 - Impoundment and disposal of unauthorized livestock.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Impoundment and disposal of unauthorized livestock. 168... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.16 Impoundment and disposal of unauthorized livestock. Unauthorized livestock within any range unit of the Hopi Partitioned Lands which are not removed therefrom...

  17. The Authority of the President to Impound Funds Appropriated by Congress.

    Science.gov (United States)

    Adams, James R.

    During fiscal year 1973, President Nixon ordered the impoundment of about 18 billion dollars in Federal funds for domestic programs. A large portion of that amount was used to slash federal funding for education programs. The entire impoundment controversy revolves around the doctrine of separation of powers. Insofar as the President has refused…

  18. Reestablishment of woody plants on mine spoils and management of mine water impoundments: an overview of Forest Service research on the northern High Plain

    Energy Technology Data Exchange (ETDEWEB)

    Bjugstad, A J

    1977-01-01

    The function of the research unit at Rapid city, S. Dakota, is to provide guidelines for the reestablisment of shrubs and trees on land characteristic of the High Plains, and for the mitigation of possible detrimental effects of surface mining on ground water and surface water. One possible problem posed by surface mining concerns the formation of land drainage patterns that could result in post-mining formations of large salt playas. Surface mining could affect shallow ground water aquifers up to /sup 1///sub 4/ mile from the mine site. Research is being conducted on the reclamation of mine spoils and on the rehabilitation and management of impounded mine water.

  19. A generic model of contaminant migration from uranium tailings impoundments

    International Nuclear Information System (INIS)

    Shepherd, T.A.; Brown, S.E.

    1982-01-01

    This paper presents an analytical hydrogeochemical model based upon acid consumption-neutralization front movement. The development of contaminant plumes is discussed and distinct zones within these plumes are identified and characterized. The most important process influencing the rate and extent of contaminant migration at acid-leach uranium tailings impoundments is the neutralization of seepage water by soils along ground water flow paths. The chemical characteristics of the ground water is determined in order to identify and characterize zones within migrating plumes of tailings-derived water. It is concluded that the characterization of specific zones is useful in the interpretation of existing conditions, in the evaluation of future migration, and in the determination of appropriate models for the specific situation

  20. Eutrophication levels of some South African impoundments. IV. Vaal Dam

    CSIR Research Space (South Africa)

    Steyn, DJ

    1976-04-01

    Full Text Available inere;iae(l the \\G P In? between 7,1- and I 1,2 mg/r? lbr t?verv nile pet? t?t?ttt v/v) added_Nitrogen and phosphorus wert? the important algal growth?limiting ntltrients in the impoundment. Plant nntt-ients adsorbed onto clay particles could ht... stream_source_info Steyn2_1976.pdf.txt stream_content_type text/plain stream_size 20870 Content-Encoding ISO-8859-1 stream_name Steyn2_1976.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Za~3n Abstract The Vital...

  1. Sedimentation in Lake Onalaska, Navigation Pool 7, upper Mississippi River, since impoundment

    Science.gov (United States)

    Korschgen, C.E.; Jackson, G.A.; Muessig, L.F.; Southworth, D.C.

    1987-01-01

    Sediment accumulation was evaluated in Lake Onalaska, a 2800-ha backwater impoundment on the Upper Mississippi River. Computer programs were used to process fathometric charts and generate an extensive data set on water depth for the lake. Comparison of 1983 survey data with pre-impoundment (before 1937) data showed that Lake Onalaska had lost less than 10 percent of its original mean depth in the 46 years since impoundment. Previous estimates of sedimentation rates based on Cesium-137 sediment core analysis appear to have been too high. (DBO)

  2. Differential effects of type of keyboard playing task and tempo on surface EMG amplitudes of forearm muscles

    Directory of Open Access Journals (Sweden)

    Hyun Ju eChong

    2015-09-01

    Full Text Available Despite increasing interest in keyboard playing as a strategy for repetitive finger exercises in fine motor skill development and hand rehabilitation, comparative analysis of task-specific finger movements relevant to keyboard playing has been less extensive. This study examined whether there were differences in surface EMG activity levels of forearm muscles associated with different keyboard playing tasks. Results demonstrated higher muscle activity with sequential keyboard playing in a random pattern compared to individuated playing or sequential playing in a successive pattern. Also, the speed of finger movements was found as a factor that affect muscle activity levels, demonstrating that faster tempo elicited significantly greater muscle activity than self-paced tempo. The results inform our understanding of the type of finger movements involved in different types of keyboard playing at different tempi so as to consider the efficacy and fatigue level of keyboard playing as an intervention for amateur pianists or individuals with impaired fine motor skills.

  3. Control of water infiltration into near surface LLW disposal units: Task report, A discussion

    International Nuclear Information System (INIS)

    Schulz, R.K.; Ridky, R.W.; O'Donnell, E.

    1988-03-01

    The principal pathway for water entry into LLW disposal units in the humid eastern United States is through their covers. Two types of sub-surface features that may be constructed to enhance run-off (surface or sub-surface run-off) and thus reduce percolation are the resistive layer barrier, and the conductive layer barrier. The resistive layer barrier is the compacted soil or compacted clay layer and depends on compaction of permeable porous material to obtain low flow rates. The conductive layer barrier is a special case of the capillary barrier. Use is made of the capillary barrier phenomenon not only to increase the moisture content above an interface but to divert water away from the waste. During such diversion the water is at all times at negative capillary potential or under tension in the flow layer. A very effective barrier system might be constructed by placing a resistive barrier over a conductive barrier. Such a system must fail if appreciable subsidence takes place. An alternate procedure called bioengineering management utilizes engineered features at the surface (as opposed to the subsurface) to ensure adequate run-off. The engineered features are combined with stressed vegetation, that is, vegetation in an overdraft condition, to control deep percolation. (59 refs., 10 figs.)

  4. Differential effects of type of keyboard playing task and tempo on surface EMG amplitudes of forearm muscles

    Science.gov (United States)

    Chong, Hyun Ju; Kim, Soo Ji; Yoo, Ga Eul

    2015-01-01

    Despite increasing interest in keyboard playing as a strategy for repetitive finger exercises in fine motor skill development and hand rehabilitation, comparative analysis of task-specific finger movements relevant to keyboard playing has been less extensive. This study examined, whether there were differences in surface EMG activity levels of forearm muscles associated with different keyboard playing tasks. Results demonstrated higher muscle activity with sequential keyboard playing in a random pattern compared to individuated playing or sequential playing in a successive pattern. Also, the speed of finger movements was found as a factor that affect muscle activity levels, demonstrating that faster tempo elicited significantly greater muscle activity than self-paced tempo. The results inform our understanding of the type of finger movements involved in different types of keyboard playing at different tempi. This helps to consider the efficacy and fatigue level of keyboard playing tasks when being used as an intervention for amateur pianists or individuals with impaired fine motor skills. PMID:26388798

  5. Effects of impoundment and regulation upon the stomach contents of fish at Cow Green, Upper Teesdale

    Energy Technology Data Exchange (ETDEWEB)

    Crisp, D.T.; Mann, R.H.K.; McCormack, J.C.

    1978-04-01

    The stomach contents of 1003 brown trout, 1551 bullheads and 800 minnows taken from the reservoir basin and below the dam, before and after impoundment of the river Tees, were examined. Their composition reflected observations by other workers on river and reservoir benthos, except for the increase in numbers of Hydra and Nais below the dam, and Mollusca, Hirudinea and oligochaetes in the reservoir. Trout below the dam ate more Ephemeroptera nymphs and Chironomidae larvae but fewer terrestrial casualties after river regulation, whereas bullheads ate more Mollusca but fewer Plecoptera nymphs. In both species Baetidae nymphs increased in numerical importance relative to Ecdyonuridae. Trout, but not bullheads, took zooplankton discharged from the reservoir. Before impoundment, trout within the reservoir basin ate chiefly benthic organisms and terrestrial casualties. Inundated terrestrial material, mainly earthworms, formed the bulk of their food for at least three years after impoundment, whilst from the second year onwards Chironomidae and, in some years, Gammarus became increasingly important. Zooplankton was taken by all sizes of reservoir trout. Bullheads within the reservoir basin ate chiefly river benthos before impoundment, with Ephemeroptera and Plecoptera nymphs predominant in older fish, and aquatic Diptera and Coleoptera also important in the fry. After impoundment, Chironomidae and Gammarus were the main items taken by older bullheads, and Chironomidae and micro-crustacea by the fry. Among all sizes of minnow, Chironomidae, micro-crustacea and detritus increased in numerical importance after impoundment.

  6. Orienting in virtual environments: How are surface features and environmental geometry weighted in an orientation task?

    Science.gov (United States)

    Kelly, Debbie M; Bischof, Walter F

    2008-10-01

    We investigated how human adults orient in enclosed virtual environments, when discrete landmark information is not available and participants have to rely on geometric and featural information on the environmental surfaces. In contrast to earlier studies, where, for women, the featural information from discrete landmarks overshadowed the encoding of the geometric information, Experiment 1 showed that when featural information is conjoined with the environmental surfaces, men and women encoded both types of information. Experiment 2 showed that, although both types of information are encoded, performance in locating a goal position is better if it is close to a geometrically or featurally distinct location. Furthermore, although features are relied upon more strongly than geometry, initial experience with an environment influences the relative weighting of featural and geometric cues. Taken together, these results show that human adults use a flexible strategy for encoding spatial information.

  7. Hydrologic considerations for rock RIPRAP protection of uranium tailings impoundments

    International Nuclear Information System (INIS)

    Walters, W.H.; Skaggs, R.L.

    1984-02-01

    Pacific Northwest Laboratory is conducting an in-depth study of the application of rock riprap for the long-term protection of uranium tailings impoundments. Decommissioned tailings sites at Grand Junction and Slickrock, Colorado were selected to review the application of riprap design methods and evaluate variable sensitivity and data requirements. Preliminary results from the Grand Junction case study indicate that the use of a safety factor in sizing the rock riprap may provide an overly conservative design that may not be justified. Some safety factor, usually a value of 1.5 to 2.0 is normally used in riprap design to allow for the uncertainties in the hydraulic calculations. The computation of the hydraulic designs variables using the probable maximum flood (PMF) event introduces conservatism into the design and the added safety factor may not be warranted. This paper presents some preliminary results from the Grand Junction site concerning the implications of using a safety factor for riprap design. 9 references, 2 figures, 2 tables

  8. Presentations from the 1992 Coal Mining Impoundment Informational Meeting

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    On May 20 and 21, 1992, the MSHA Coal Mining Impoundment Informational Meeting was held at the National Mine Health and Safety Academy in Beckley, West Virginia. Fifteen presentations were given on key issues involved in the design and construction of dams associated with coal mining. The attendees were told that to improve the consistency among the plan reviewers, engineers from the Denver and Pittsburgh Technical Support Centers meet twice annually to discuss specific technical issues. It was soon discovered that the topics being discussed needed to be shared with anyone involved with coal waste dam design, construction, or inspection. The only way to accomplish that goal was through the issuance of Procedure Instruction Letters. The Letters present a consensus of engineering philosophy that could change over time. They do not present policy or carry the force of law. Currently, thirteen position papers have been disseminated and more will follow as the need arises. The individual paper were not even entered into the database.

  9. A systematic review of surface electromyography analyses of the bench press movement task.

    Directory of Open Access Journals (Sweden)

    Petr Stastny

    Full Text Available The bench press exercise (BP plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed?PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered.The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB and pectoralis major (PM muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change.PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits or guidelines for the use of exact muscle models.

  10. A systematic review of surface electromyography analyses of the bench press movement task.

    Science.gov (United States)

    Stastny, Petr; Gołaś, Artur; Blazek, Dusan; Maszczyk, Adam; Wilk, Michał; Pietraszewski, Przemysław; Petr, Miroslav; Uhlir, Petr; Zając, Adam

    2017-01-01

    The bench press exercise (BP) plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG) studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed? PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered. The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB) and pectoralis major (PM) muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change. PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits) or guidelines for the use of exact muscle models.

  11. A systematic review of surface electromyography analyses of the bench press movement task

    Science.gov (United States)

    Gołaś, Artur; Blazek, Dusan; Maszczyk, Adam; Wilk, Michał; Pietraszewski, Przemysław; Petr, Miroslav; Uhlir, Petr; Zając, Adam

    2017-01-01

    Background The bench press exercise (BP) plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG) studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed? Strategy PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered. Results The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB) and pectoralis major (PM) muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change. Conclusions PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits) or guidelines for the use of exact muscle models. PMID

  12. The fish community of a small impoundment in upstate New York

    Science.gov (United States)

    McCoy, C. Mead; Madenjian, Charles P.; Adams, Jean V.; Harman, Willard N.

    2001-01-01

    Moe Pond is a dimictic impoundment with surface area of 15.6 ha, a mean depth of 1.8 m, and an unexploited fish community of only two species: brown bullhead (Ameiurus nebulosus) and golden shiner (Notemigonus crysoleucas). The age-1 and older brown bullhead population was estimated to be 4,057 individuals, based on the Schnabel capture-recapture method of population estimation. Density and biomass were respectively estimated at 260 individuals/ha and 13 kg/ha. Annual survival rate of age-2 through age-5 brown bullheads was estimated at 48%. The golden shiner length-frequency distribution was unimodal with modal length of 80 mm and maximum total length of 115 m. The golden shiner population estimate was 7,154 individuals, based on seven beach seine haul replicate samples; the density and biomass were 686 shiners/ha and 5 kg/ha, respectively. This study provides an information baseline that may be useful in understanding food web interactions and whole-pond nutrient flux.

  13. The hydrogeochemistry of four inactive tailings impoundments: Perspectives on tailings pore-water evolution

    International Nuclear Information System (INIS)

    Blowes, D.W.; Cherry, J.A.; Reardon, E.J.

    1987-01-01

    Extensive hydrogeochemical investigations are currently underway at three inactive tailings impoundments in Canada. These programs include detailed measurements of pore-water and gas-phase geochemistry through the vadose zone and the groundwater zone. An extensive piezometer network has been installed at each location to monitor the groundwater flow regime. All of the impoundments studied have been inactive for 15 to 25 years, sufficient time for extensive tailings pore-water evolution. The study areas include a very high-sulfide impoundment, a low-sulfide, high-carbonate impoundment, a low-sulfide, very low-carbonate impoundment, and a moderately high-sulfide impoundment. The pore water at each of the sites has evolved in a distinctly different and characteristic manner, representing broad styles of tailings pore-water evolution. At the high sulfide impoundment the oxidation of sulfide minerals has resulted in low pH, high redox potential conditions, with Fe 2+ concentrations in excess of 60,000 mg/L. At a depth of about 40 cm a 10 cm thick layer of ferrous and calcium sulfate minerals has precipitated. This hardpan layer limits the downward movement of O 2 and infiltrating pore waters. As a result, the pore water chemistry, both above and below the hardpan layer, has remained relatively unchanged over the past 10 years. The low-sulfide, high-carbonate tailings are sufficiently well buffered that no low pH conditions are present. The high pH conditions limit the concentrations of the metals released by sulfide mineral oxidation to levels that are two or three orders of magnitude less than is observed at the high-sulfide site. Pore waters at the low-sulfide, low-carbonate site were sampled by other researchers from the University of Waterloo

  14. The role of cassiterite controlling arsenic mobility in an abandoned stanniferous tailings impoundment at Llallagua, Bolivia.

    Science.gov (United States)

    Romero, Francisco Martín; Canet, Carles; Alfonso, Pura; Zambrana, Rubén N; Soto, Nayelli

    2014-05-15

    The surface water contamination by potentially toxic elements (PTE) leached from mine tailings is a major environmental concern. However, the formation of insoluble solid phases can control the mobility of PTE, with subsequent decrease of the risk that tailings suppose to the environment. We characterized the tailings from a tin inactive mine in Llallagua, Bolivia in order to assess the risk for surface water quality. These tailings contain high concentrations of PTE, with up to 94,344 mg/kg Fe, 9,135 mg/kg Sn, 4,606 mg/kg As, 1,362 mg/kg Cu, 1,220 mg/kg Zn, 955 mg/kg Pb and 151 mg/kg Cd. Oxidation of sulfide minerals in these tailings generates acid leachates (pH=2.5-3.5), rich in SO4(2-) and dissolved PTE, thereby releasing contaminants to the surface waters. Nevertheless, the concentrations of dissolved Sn, As and Pb in acid leachates are low (Sntailing deposits; it should be the main solid phase controlling Sn and As mobility in the impoundment. Additionally, jarosite and plumbojarosite, identified among the secondary minerals, could also play an important role controlling the mobility of As and Pb. Taking into account (a) the low solubility constants of cassiterite (Ksp=10(-64.2)), jarosite (Ksp=10(-11)) and plumbojarosite (Ksp=10(-28.66)), and (b) the stability of these minerals under acidic conditions, we can conclude that they control the long-term fate of Sn, As and Pb in the studied tailings. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The impact of impoundment on the rotifer communities in two tropical floodplain environments: interannual pulse variations

    Directory of Open Access Journals (Sweden)

    CC. Bonecker

    Full Text Available Hydrological pulses are the main factor regulating the structure of biological communities in floodplains. Reservoirs above this ecosystem change the environment's dynamics and the community's biodiversity. This study evaluated the structure and stability of the rotifer community in response to changes in hydrological pulses after the Porto Primavera impoundment in the Upper Paraná River floodplain. The community was studied in a river and in a floodplain lake downstream of the dam over a four-year period before and after the impoundment. A decrease in species richness and abundance was observed soon after the impoundment, followed by an increase in these attributes and in specific diversity when the hydrometric level of the Paraná River rose and, consequently, increased the connectivity between the floodplain environments. Conochilus coenobasis, Filinia longiseta, Keratella cochlearis, Lecane proiecta and Polyarthra dolichoptera persisted throughout the study and contributed to community stability (the maintenance of rank in species abundance over time, which was high in the floodplain lake, mainly after the impoundment. Reductions in the frequency, intensity and amplitude of potamophase pulses after the impoundment led to the decrease in species richness and the increases in abundance, community stability, and species diversity, which determine community resilience.

  16. Using Helicopter Electromagnetic Surveys to Identify Potential Hazards at Mine Waste Impoundments

    Energy Technology Data Exchange (ETDEWEB)

    Hammack, R.W.

    2008-01-01

    In July 2003, helicopter electromagnetic surveys were conducted at 14 coal waste impoundments in southern West Virginia. The purpose of the surveys was to detect conditions that could lead to impoundment failure either by structural failure of the embankment or by the flooding of adjacent or underlying mine works. Specifically, the surveys attempted to: 1) identify saturated zones within the mine waste, 2) delineate filtrate flow paths through the embankment or into adjacent strata and receiving streams, and 3) identify flooded mine workings underlying or adjacent to the waste impoundment. Data from the helicopter surveys were processed to generate conductivity/depth images. Conductivity/depth images were then spatially linked to georeferenced air photos or topographic maps for interpretation. Conductivity/depth images were found to provide a snapshot of the hydrologic conditions that exist within the impoundment. This information can be used to predict potential areas of failure within the embankment because of its ability to image the phreatic zone. Also, the electromagnetic survey can identify areas of unconsolidated slurry in the decant basin and beneath the embankment. Although shallow, flooded mineworks beneath the impoundment were identified by this survey, it cannot be assumed that electromagnetic surveys can detect all underlying mines. A preliminary evaluation of the data implies that helicopter electromagnetic surveys can provide a better understanding of the phreatic zone than the piezometer arrays that are typically used.

  17. Diet and trophic structure of the fish fauna in a subtropical ecosystem: impoundment effects

    Directory of Open Access Journals (Sweden)

    Rosilene Luciana Delariva

    Full Text Available This study examined the diet and trophic structure of the fish fauna, over temporal and spatial scales, as affected by the impoundment of the Iguaçu River in the region of Salto Caxias, Paraná State, Brazil. Sampling was conducted before (March 1997 - February 1998 and after the impoundment (March 1999 - February 2000, at four sampling sites. The stomach contents were analyzed by the volumetric method. The species could be organized in 10 trophic guilds: algivores, carcinophages, detritivores, herbivores, aquatic insectivores, terrestrial insectivores, invertivores, omnivores, piscivores, and planktivores; the first and last guilds were represented only in the post-impoundment period. Similarity patterns and feeding changes were summarized by a non-metric Multi-dimensional Scaling (nMDS analysis and statistically tested by a Permutational multivariate analysis of variance (PERMANOVA. Most species showed feeding changes, except for the piscivores and detritivores. These changes were related to the temporal factor (impoundment phases, such as reduced intake of benthic organisms and allochthonous food, which were usually replaced by resources from the reservoir itself (algae, microcrustaceans, and fish, simplifying the food spectrum of the fish fauna. A different indicator of food resources (IndVal corroborated these changes in the feeding of the species. The proportions of the trophic guilds evaluated based on the catch per unit of effort (CPUE and tested by ANOSIM were significantly different before and after the impoundment. Herbivores and piscivores were the guilds that contributed (SIMPER to these differences, especially the high increase in biomass of the piscivore guild after the impoundment. Variations in the abundance of trophic guilds were more directly related to changes in the feeding habits of the fish fauna than to increases in the number and biomass of the species that constitute these guilds.

  18. Limnology and fisheries of three recently impounded reservoirs in Sri Lanka

    International Nuclear Information System (INIS)

    Silva, K.H.G.M De

    1990-01-01

    The hydroelectric reservoirs of Kotmale, Victoria, and Randenigala were impounded in 1985, 1984, and 1986, respectively, by damming the Mahaweli River. The surface area, maximum depth, and mean depth of the three reservoirs are 6.3 km 2 , 78 m, 27.6 m; 23.7 km 2 , 102 m, 30.8 m; and 23.5 km 2 , 90 m, 36.6 m respectively, at their full supply levels of 703, 438, and 232 m above mean sea level. Important physicochemical factors and phytoplankton were studied by sampling of subsurface waters every two weeks in 12 randomly chosen stations in Randenigala and Victoria, and in 10 stations in Kotmale over 24 months. Mean water temperature, pH, conductivity, and the total alkalinity during the study period were 25.6 degree C, 6.6, 50.7 μsieverts, and 0.31 millimoles/l in Kotmale, 26.9 degree C, 7.1, 77.4 μsieverts, and 0.62 millimoles/l in Victoria, and 28.3 degree C, 7.4, 90.0 μsieverts, and 0.79 millimoles/l in Randenigala. The gill-net catches of Kotmale and Victoria are ca 38 and 70 kg/hectare/y, respectively. Randenigala has a fishery potential of ca 70 kg/hectare/y. Tilapia formed ca 68%, 59%, and 69% of the catches of Kotmale, Victoria, and Randenigala, respectively. The catch at Kotmale was mainly Java tilapia and Nile tilapia, whereas at the other two reservoirs it was mainly Java tilapia. Indigenous species constituted only ca 10% of the catch. 16 refs., 2 figs., 4 tabs

  19. Effects of increased summer flooding on nitrogen dynamics in impounded mangroves

    NARCIS (Netherlands)

    Verhoeven, Jos T A; Laanbroek, Hendrikus J; Rains, Mark C; Whigham, Dennis F

    2014-01-01

    Mangroves are important for coastal protection, carbon sequestration and habitat provision for plants and animals in the tropics and subtropics. Mangroves are threatened by habitat destruction and sea level rise, but management activities such as impounding for mosquito control can also have

  20. Postural control and cognitive task performance in healthy participants while balancing on different support-surface configurations

    NARCIS (Netherlands)

    Dault, MC; Mulder, TW; Duysens, J

    2001-01-01

    Postural control during normal upright stance in humans is a well-learned task. Hence, it has often been argued that it requires very little attention. However, many studies have recently shown that postural control is modified when a cognitive task is executed simultaneously especially in the

  1. Cumulative impoundment evaporation in water resource management within the mid-Atlantic: A case study in Virginia

    Science.gov (United States)

    Scott, D.; Burgholzer, R.; Kleiner, J.; Brogan, C. O.; Julson, C.; Withers, E.

    2017-12-01

    Across the eastern United States, successful management of water resources to satisfy the competing demands for human consumption, industry, agriculture, and ecosystems requires both water quality and water quantity considerations. Over the last 2 decades, low streamflows during dry summers have increased scrutiny on water supply withdrawals. Within Virginia, a statewide hydrologic model provides quantitative assessments on impacts from proposed water withdrawals to downstream river flow. Currently, evaporative losses are only accounted for from the large reservoirs. In this study, we sought to provide a baseline estimate for the cumulative evaporation from impoundments across all of the major river basins in Virginia. Virginia provides an ideal case study for the competing water demands in the mid-Atlantic region given the unique tracking of water withdrawals throughout the river corridor. In the over 73,000 Virginia impoundments, the cumulative annual impoundment evaporation was 706 MGD, or 49% of the permitted water withdrawal. The largest reservoirs (>100 acres) represented over 400 MGD, and 136 MGD for the smaller impoundments (water loss (evaporation + demand), with some areas where impoundment evaporation was greater than human water demand. Seasonally, our results suggest that cumulative impoundment evaporation in some watersheds greatly impacts streamflow during low flow periods. Our results demonstrate that future water supply planning will require not only understanding evaporation within large reservoirs, but also the thousands of small impoundments across the landscape.

  2. The Impact of Impoundment on Mercury Bioaccumulation in Fish Downstream from a Newly Constructed Reservoir, Wujiang River, Southwest China.

    Science.gov (United States)

    Li, Sixin; Zhou, Lianfeng; Chang, Jianbo; Yang, Zhi; Hu, Juxiang; Hongjun, Wang

    2017-11-01

    Mercury concentrations in fish were investigated downstream from a newly impounded subtropical reservoir in August 2008. After 6-7 months of reservoir impoundment, mean mercury concentration in fish from downstream is significantly increased by 1.9 times. Not only carnivorous fish but also benthic fish had significantly higher total mercury concentrations than others. No significant correlation was found between total mercury concentrations and body length or weight of 13 fish species. Compared with the pre-impoundment, total mercury in fish from downstream is significantly increased by reservoir impoundment, but the increased rate is lower than those in subarctic and temperate areas. Fish samples surpassed the Chinese hygienic standard for tolerances of mercury in foods increased by 4.3%. More attention should be given to fish mercury levels from downstream sites to prevent possible adverse effects on the health of local people.

  3. Organochlorine pesticide levels in Clarias gariepinus from polluted freshwater impoundments in South Africa and associated human health risks

    CSIR Research Space (South Africa)

    Barnhoorn, IEJ

    2014-02-01

    Full Text Available There are increasing concerns regarding the safe human consumption of fish from polluted, freshwater impoundments. The aim of this study was to analyse the muscle tissue of the sharptooth catfish Clarias gariepinus for selected organo-chlorine...

  4. 30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

    Science.gov (United States)

    2010-07-01

    ... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND... instrumentation. (9) Graphs showing area-capacity curves. (10) A statement of the runoff attributable to the probable maximum precipitation of 6-hour duration and the calculations used in determining such runoff. (11...

  5. Rock riprap design methods and their applicability to long-term protection of uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Walters, W.H.

    1982-08-01

    This report reviews the more accepted or recommended riprap design methods currently used to design rock riprap protection against soil erosion by flowing water. The basic theories used to develop the various methods are presented. The Riprap Design with Safety Factors Method is identified as the logical choice for uranium mill tailings impoundments. This method is compared to the other methods and its applicability to the protection requirements of tailings impoundments is discussed. Other design problems are identified and investigative studies recommended

  6. Geomorphological assessment of sites and impoundments for the long term containment of uranium mill tailings in the Alligator Rivers Region

    International Nuclear Information System (INIS)

    East, T.J.

    1986-01-01

    This paper presents a program of current and future research into those geomorphological processes likely to affect the long term containment of uranium mill tailings in the Alligator Rivers Region of the Northern Territory. Research is directed at three main areas: identification of geomorphic hazards at proposed impoundment sites; determination of erosion rates on impoundment slopes; and prediction of patterns of fluvial dispersal of released tailings. Each necessitates consideration of present and future geomorphic processes

  7. Profiling of Sediment Microbial Community in Dongting Lake before and after Impoundment of the Three Gorges Dam

    Directory of Open Access Journals (Sweden)

    Wei Huang

    2016-06-01

    Full Text Available The sediment microbial community in downstream-linked lakes can be affected by the operation of large-scale water conservancy projects. The present study determined Illumina reads (16S rRNA gene amplicons to analyze and compare the bacterial communities from sediments in Dongting Lake (China before and after impoundment of the Three Gorges Dam (TGD, the largest hydroelectric project in the world. Bacterial communities in sediment samples in Dongting Lake before impoundment of the TGD (the high water period had a higher diversity than after impoundment of the TGD (the low water period. The most abundant phylum in the sediment samples was Proteobacteria (36.4%–51.5%, and this result was due to the significant abundance of Betaproteobacteria and Deltaproteobacteria in the sediment samples before impoundment of the TGD and the abundance of Gammaproteobacteria in the sediment samples after impoundment of the TGD. In addition, bacterial sequences of the sediment samples are also affiliated with Acidobacteria (11.0% on average, Chloroflexi (10.9% on average, Bacteroidetes (6.7% on average, and Nitrospirae (5.1% on average. Variations in the composition of the bacterial community within some sediment samples from the river estuary into Dongting Lake were related to the pH values. The bacterial community in the samples from the three lake districts of Dongting Lake before and after impoundment of the TGD was linked to the nutrient concentration.

  8. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  9. Modelling of contaminant migration in acidic groundwater plumes at uranium tailings impoundments: ADNEUT3

    International Nuclear Information System (INIS)

    Cherry, J.A.; Morin, K.A.; Dubrovsky, N.M.

    1984-06-01

    This report describes the creation and application of ADNEUT3, the latest addition to the ADNEUT (Acid-Drainage NEUTralization) family of computer programs for simulating acid-drainage transport and neutralization. The creation of ADNEUT3 involved the expansion of ADNEUT1 to allow variable input conditions such as changing input solution with time, variable initial amounts of minerals through the simulated streamtube, variable velocities through the streamtube, and variable solubilities for relevant minerals dependent on aqueous chemical composition. Concepts for simulating acid-drainage neutralization are reviewed and ADNEUT3 is then applied to a field-study site of acidic contaminant migration from the Nordic Main uranium-tailings impoundment near Elliot Lake, Ontario. A sensitivity study is first implemented to calibrate ADNEUT3 to the results of the 1979 to 1983 field studies. Then ADNEUT3 is used to define probable past conditions at the site which are not reliably known. In particular, ADNEUT3 is used to help identify: 1) the approximate year when acidic seepage began leaving the tailings impoundment (1966-1967), 2) the past chemical composition of the seepage (somewhat more acidic for a short period of time), and 3) the location of the source area within the tailings for the acidic seepage (near the impoundment dam, close to the field site). Finally, ADNEUT3 is used to predict future contaminant migration. Results indicate that hundreds of years are required under present conditions for the most acidic water with associated high levels of contaminants to migrate about 100 m from the tailings impoundment. The cause of this slow movement is the significant neutralization capacity of the aquifer. If acid production within the tailings decreases in the future, migration rates of contaminants will also decrease

  10. Impacts of Freshwater Impoundment in the West Loch of Pearl Harbor

    Science.gov (United States)

    1993-05-01

    absence of applicable non-point standards, the "Yellow Book" criteria for freshwater aquatic life or domestic water supply could be applied to evaluate the...Waimalu, Waipahu, Wahiawa, and Ewa water use districts and contains the largest groundwater body on Oahu, supplying more than 50 percent of the island’s...irrigation; desalt existing brackish water supplies, and; 3 create a freshwater impoundment in West Loch. 6I I I The Board of Water Supply (BWS) and

  11. The geo-environmental design of a coal refuse impoundment in Illinois

    International Nuclear Information System (INIS)

    Ripp, B.J.

    1997-01-01

    The coal refuse impoundment discussed was one of the first permitted under new regulatory standards within the State of Illinois. The new standards go beyond the geotechnial stability of the structure and must address the groundwater quality of the area and the impact of the impoundment on the groundwater system. The geotechnial design of the coal refuse impoundment dam and associated structures had its own particular challenges such as: 1) the construction of the structure over mined workings; 2) the close proximity of seismically active fault zones; and 3) the embankment configuration being controlled by the material balance of the mine refuse. The implementation of the groundwater protection plan included: 1) incorporating the groundwater quality standards and sampling protocols of several state agencies while the standards were being drafted; 2) sampling of the potential sources of groundwater impact; 3) establishing background levels; and 4) establishing the groundwater class. An initial groundwater transport model was developed and used as the basis for recommending a groundwater monitoring design in place of constructing a soil or synthetic liner. 15 refs., 2 figs., 3 tabs

  12. Effect of ship locking on sediment oxygen uptake in impounded rivers

    DEFF Research Database (Denmark)

    Lorke, A.; McGinnis, D. F.; Maeck, A.

    2012-01-01

    In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy....... Additional means by which the oxygen budget of the impoundment is affected by lock-induced flow variations are discussed. Citation: Lorke, A., D. F. McGinnis, A. Maeck, and H. Fischer (2012), Effect of ship locking on sediment oxygen uptake in impounded rivers, Water Resour. Res., 48, W12514, doi: 10....... These wave-induced flow variations cause variations in sediment-water oxygen fluxes. While the mean flux during time periods without lock operation was 0.5 +/- 0.1 g m(-2) d(-1), it increased by about a factor of 2 to 1.0 +/- 0.5 g m(-2) d(-1) within time periods with ship locking. Following the daily...

  13. Dose assessment of remedial action for uranium tailing impoundment of a nuclear factory

    International Nuclear Information System (INIS)

    Li Xutong; Ma Ruwei; Guo Zede

    2000-01-01

    A large uranium tailing impoundment in China will be closure and remedial action have been planned. The remedial action will include shaping and covering the dam and beach in order to prevent the impoundment from damage and restrict spread of tailing sands and emission of radon. The author presents the analysis and estimation of the exposure to workers for remedial action and to public after the remedial action. To estimate the exposure to workers, the pathway of inhalation of radon, tailing sands in suspension and external γ exposure were taken into consideration. The exposure scenario is considered as probably maximum exposure to the workers who work on the tailing pile without any protection measures, the dose is 6.0 mSv/a. Two situation for the exposure to public after remedial action were considered: normal and abnormal condition. For the normal condition, inhalation of radon emitted from impoundment is only the pathway to public for the exposure, and individual dose for critical group of public is 0.053 mSv/a, collective dose for population within 80 km is 1.0 man·Sv/a. For the abnormal conditions, four scenarios were considered, i.e. dwelling on tailing pile, farming on tailing pile, living in a house built by contaminated materials and some temporal activities on the pile. The scenarios of dwellings is living in a house on the pile and drinking contaminated water. The maximum individual dose is 27 mSv/a

  14. Thinking Aloud While Solving a Stock-Flow Task: Surfacing the Correlation Heuristic and Other Reasoning Patterns

    NARCIS (Netherlands)

    Korzilius, H.P.L.M.; Raaijmakers, S.F.J.M.; Rouwette, E.A.J.A.; Vennix, J.A.M.

    2014-01-01

    In the literature, it is assumed that individuals, while performing stock-flow tasks, often use a correlation heuristic, a form of pattern matching in which they think that the behavior of the stock resembles the (net) flow. To investigate this assumption and to increase our insight in the actual

  15. Characterization of the rock joint surface. A contribution to DECOVALEX II Task 3 'Constitutive relationships of rock joints'

    International Nuclear Information System (INIS)

    Vuopio, J.; Poellae, J.

    1997-12-01

    In order to understand the effects of spent fuel on the hydraulical behaviour of the rock mass it is necessary to have knowledge about the relationship between the stresses and hydraulical properties of the fractures. The roughness of a fracture surface governs the dilatation of the fracture and the displacement of the fracture surface under shear stress. The peak shear strength and hydraulic flow properties of fractures depend very much on the surface roughness. This report describes different methods and techniques used in the characterization of rock joint surfaces and their applications in rock mechanics

  16. Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia.

    Science.gov (United States)

    Hiller, Edgar; Petrák, Marián; Tóth, Roman; Lalinská-Voleková, Bronislava; Jurkovič, L'ubomír; Kučerová, Gabriela; Radková, Anežka; Sottník, Peter; Vozár, Jaroslav

    2013-11-01

    mineral assemblage and their occurrence follows the order: chalcopyrite > pyrite > tetrahedrite>arsenopyrite. The mineralogical composition of the tailings corresponds well to the primary mineralization mined. The neutralization capacity of the tailings is high, as confirmed by the values of neutralization potential to acid generation potential ratio, ranging from 6.7 to 63.9, and neutral to slightly alkaline pH of the tailings (paste pH 7.16-8.12) and the waters (pH 7.00-8.52). This is explained by abundant occurrence of carbonate minerals in the tailings, which readily neutralize the acidity generated by sulfide oxidation. The total solid-phase concentrations of metal(loid)s decrease as Cu>Sb>Hg>As and reflect the proportions of sulfides present in the tailings. Sulfide oxidation generally extends to a depth of 2 m. μ-XRD and EMPA were used to study secondary products developed on the surface of sulfide minerals and within the tailings. The main secondary minerals identified are goethite and X-ray amorphous Fe oxyhydroxides and their occurrence decreases with increasing tailings depth. Secondary Fe phases are found as mineral coatings or individual grains and retain relatively high amounts of metal(loid)s (up to 57.6 wt% Cu, 1.60 wt% Hg, 23.8 wt% As, and 2.37 wt% Sb). Based on batch leaching tests and lysimeter results, the mobility of potentially toxic elements in the tailings is low. The limited mobility of metals and metalloids is due to their retention by Fe oxyhydroxides and low solubilities of metal(loid)-bearing sulfides. The observations are consistent with PHREEQC calculations, which predict the precipitation of Fe oxyhydroxides as the main solubility-controlling mineral phases for As, Cu, Hg, and Sb. Waters discharging from tailings impoundment are characterized by a neutral to slightly alkaline pH (7.52-7.96) and low concentrations of dissolved metal(loid)s (tailings impoundment.

  17. Pre- and post-impoundment nitrogen in the lower Missouri River

    Science.gov (United States)

    Blevins, Dale W.; Wilkison, Donald H.; Niesen, Shelley L.

    2013-01-01

    Large water-sample sets collected from 1899 through 1902, 1907, and in the early 1950s allow comparisons of pre-impoundment and post-impoundment (1969 through 2008) nitrogen concentrations in the lower Missouri River. Although urban wastes were not large enough to detectably increase annual loads of total nitrogen at the beginning of the 20th century, carcass waste, stock-yard manure, and untreated human wastes measurably increased ammonia and organic-nitrogen concentrations during low flows. Average total-nitrogen concentrations in both periods were about 2.5 mg/l, but much of the particulate-organic nitrogen, which was the dominant form of nitrogen around 1900, has been replaced by nitrate. This change in speciation was caused by the nearly 80% decrease in suspended-sediment concentrations that occurred after impoundment, modern agriculture, drainage of riparian wetlands, and sewage treatment. Nevertheless, bioavailable nitrogen has not been low enough to limit primary production in the Missouri River since the beginning of the 20th century. Nitrate concentrations have increased more rapidly from 2000 through 2008 (5 to 12% per year), thus increasing bioavailable nitrogen delivered to the Mississippi River and affecting Gulf Coast hypoxia. The increase in nitrate concentrations with distance downstream is much greater during the post-impoundment period. If strategies to decrease total-nitrogen loads focus on particulate N, substantial decreases will be difficult because particulate nitrogen is now only 23% of total nitrogen in the Missouri River. A strategy aimed at decreasing particulates also could further exacerbate land loss along the Gulf of Mexico, which has been sediment starved since Missouri River impoundment. In contrast, strategies or benchmarks aimed at decreasing nitrate loads could substantially decrease nitrogen loadings because nitrates now constitute over half of the Missouri's nitrogen input to the Mississippi. Ongoing restoration and creation

  18. Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography.

    Science.gov (United States)

    Ali, Asraf; Sundaraj, Kenneth; Badlishah Ahmad, R; Ahamed, Nizam Uddin; Islam, Anamul; Sundaraj, Sebastian

    2015-06-27

    The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = -2.863), followed by the medial head (slope = -2.412) and the lateral head (slope = -1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

  19. Sediment transport to and from small impoundments in northeast Kansas, March 2009 through September 2011

    Science.gov (United States)

    Foster, Guy M.; Lee, Casey J.; Ziegler, Andrew C.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 through September 2011. Streamgages and continuous turbidity sensors were operated upstream and downstream from Atchison County, Banner Creek, and Centralia Lakes to study the effect of varied watershed characteristics and agricultural practices on sediment transport in small watersheds in northeast Kansas. Atchison County Lake is located in a predominantly agricultural basin of row crops, with wide riparian buffers along streams, a substantial amount of tile drainage, and numerous small impoundments (less than 0.05 square miles; hereafter referred to as “ponds”). Banner Creek Lake is a predominantly grassland basin with numerous small ponds located in the watershed, and wide riparian buffers along streams. Centralia Lake is a predominantly agricultural basin of row crops with few ponds, few riparian buffers along streams, and minimal tile drainage. Upstream from Atchison County, Banner Creek, and Centralia Lakes 24, 38, and 32 percent, respectively, of the total load was transported during less than 0.1 percent (approximately 0.9 days) of the time. Despite less streamflow in 2011, larger sediment loads during that year indicate that not all storm events transport the same amount of sediment; larger, extreme storms during the spring may transport much larger sediment loads in small Kansas watersheds. Annual sediment yields were 360, 400, and 970 tons per square mile per year at Atchison County, Banner, and Centralia Lake watersheds, respectively, which were less than estimated yields for this area of Kansas (between 2,000 and 5,000 tons per square mile per year). Although Centralia and Atchison County Lakes had similar percentages of agricultural land use, mean annual sediment yields upstream from Centralia Lake were about 2.7 times

  20. Geomorphological assessment of sites and impoundments for the long term containment of uranium mill tailings in the Alligator Rivers Region

    International Nuclear Information System (INIS)

    East, T.J.

    1985-01-01

    Current and future research into the geomorphological processes likely to affect the long term containment of uranium mill tailings in the Alligator Rivers Region is directed at three main areas: identification of geomorphic hazards at proposed impoundment sites; determination of erosion rates on impoundment slopes; and prediction of patterns of fluvial dispersal of released tailings. Each necessitates consideration of present and future geomorphic processes. Process rates during the next few thousand years might be predictable by extrapolation of contemporary and past (i.e. Holocene) climates, sea-levels and depositional environments, evidence for which is preserved in the sedimentary record. In current projects, the Late Quarternary stratigraphy of Magela Creek are examined to provide data for modelling of present and future sedimentological processes. Site stability evaluation entails recognition of present and future geomorphic hazards at impoundment sites, and includes fluvial and hillslope erosion, extreme flood events and mass movements. The life of a tailings impoundment is further determined by the intensity of erosional processes acting upon its slopes and their cover materials. A knowledge of present and future erosion rates will allow the optimisation of slope characteristics and materials in the impoundment design

  1. 40 CFR 63.134 - Process wastewater provisions-surface impoundments.

    Science.gov (United States)

    2010-07-01

    ..., and semi-annually thereafter, for improper work practices and control equipment failures in accordance... this subpart, when an improper work practice or a control equipment failure is identified, first... treats a Group 1 wastewater stream or a residual removed from a Group 1 wastewater stream, the owner or...

  2. Relationships among catch, angler catisfaction, and fish assemblage characteristics of an urban small impoundment fishery

    Science.gov (United States)

    Ivasauskas, Tomas J.; Xiong, Wilson N.; Engman, Augustin C.; Fischer, Jesse R.; Kwak, Thomas J.; Rundle, Kirk R.

    2017-01-01

    Urban fisheries provide unique angling opportunities for people from traditionally underrepresented demographics. Lake Raleigh is a 38-ha impoundment located on the North Carolina State University campus in Raleigh. Like many urban fisheries, little is known about angler use and satisfaction or how angling catch rate is related to fish availability in Lake Raleigh. We characterized the recreational fishery and fish assemblage with concurrent creel and boat electrofishing surveys over the course of one year. In total, 245 anglers were interviewed on 68 survey days. On average, anglers spent 1.7 h fishing per trip and caught 0.385 fish h –1. A large proportion of anglers (43.9%) targeted multiple species, whereas 36.5% targeted largemouth bass (Micropterus salmoides), 10.0% targeted panfish (i.e., sunfishes [Lepomis spp.] and crappies [Pomoxis spp.]), and 9.6% targeted catfish (Ameiurus spp. and Ictalurus spp.). Most anglers (69.4%) were satisfied with their experience, and overall satisfaction was unrelated to catch rate. Pulsed-DC boat electrofishing was conducted on 25 dates, and 617 fish were sampled. Angler catch rate was unrelated to electrofishing catch rate, implying that anglers' catch rate was independent of fish density or availability. Our results demonstrate that even minimally managed urban fisheries can provide high angler satisfaction, with limited dedication of management resources. Relationships Among Catch, Angler Satisfaction, and Fish Assemblage Characteristics of an Urban Small Impoundment Fishery (PDF Download Available). Available from: https://www.researchgate.net/publication/316636550_Relationships_Among_Catch_Angler_Satisfaction_and_Fish_Assemblage_Characteristics_of_an_Urban_Small_Impoundment_Fishery [accessed Aug 11, 2017].

  3. Cyanobacteria and cyanotoxins are present in drinking water impoundments and groundwater wells in desert environments.

    Science.gov (United States)

    Chatziefthimiou, Aspassia D; Metcalf, James S; Glover, W Broc; Banack, Sandra A; Dargham, Soha R; Richer, Renee A

    2016-05-01

    Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have invested in infrastructure development of desalination plants. Collectively, the countries of the Arabian Gulf produce 45% of the world's desalinated water, which is stored in dams, mega-reservoirs and secondary house water tanks to secure drinking water beyond daily needs. Improper storage practices of drinking water in impoundments concomitant with increased temperatures and light penetration may promote the growth of cyanobacteria and accumulation of cyanotoxins. To shed light on this previously unexplored research area in desert environments, we examined drinking and irrigation water of urban and rural environments to determine whether cyanobacteria and cyanotoxins are present, and what are the storage and transportation practices as well as the environmental parameters that best predict their presence. Cyanobacteria were present in 80% of the urban and 33% of the rural water impoundments. Neurotoxins BMAA, DAB and anatoxin-a(S) were not detected in any of the water samples, although they have been found to accumulate in the desert soils, which suggests a bioaccumulation potential if they are leached into the aquifer. A toxic BMAA isomer, AEG, was found in 91.7% of rural but none of the urban water samples and correlated with water-truck transportation, light exposure and chloride ions. The hepatotoxic cyanotoxin microcystin-LR was present in the majority of all sampled impoundments, surpassing the WHO provisional guideline of 1 μg/l in 30% of the urban water tanks. Finally, we discuss possible management strategies to improve storage and transportation practices in order to minimize exposure to cyanobacteria and cyanotoxins, and actions to promote sustainable use of limited water resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. contaminant migration in a sand aquifer near an inactive uranium tailings impoundment, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Morin, K.A.; Cherry, J.A.

    1982-01-01

    An investigation of the movement of contaminated groundwater from inactive uranium tailings through a sand aquifer is being conducted at the Nordic Main tailings impoundment near Elliot Lake, Ontario. During 1979 and 1980, multilevel bundle-type piezometers were installed at several locations around the edge of the tailings impoundment. Chemical analysis of water samples from the bundle piezometers indicate that a major contaminant plume extends outward through a sand aquifer from the southeastern part of the Nordic Main impoundment dam. In the vincinity of the contaminant plume, the sand aquifer varies in thickness from about 9 to 15 m. The plume has two distinct segments, referred to as the inner core and the outer zone. The inner core, which has a pH of 4.3-5.0 and extends about 15 m from the foot of the tailings dam, contains several grams per litre of iron and sulfate, and tens of pCi/L of 226 Ra and 210 Pb. Water levels in piezometers within the inner core show that groundwater is moving horizontally, away from the tailings impoundment, with a velocity of up to several hundred metres per year. The outer zone, which extends a few hundred metres downgradient from the dam, is characterized by hundreds to thousands of milligrams per litre of iron and sulfate, less than 15pCi/L of 226 Ra, and a pH greater than 5.7. Comparison of 1979 and 1980 data shows that the front of the inner core is advancing a few metres per year, which is less than a few percent of the groundwater velocity. This retardation of movement of the inner core is caused by neutralization of the acidic water as a result of dissolution of calcium carbonate in the sand. With the rise in pH, precipitation of iron carbonate and possibly some iron hydroxide occurs and the contaminants of main concern such as 226 Ra, 210 Pb, and uranium are removed from solution by adsorption or coprecipitation

  5. An Object-Based Machine Learning Classification Procedure for Mapping Impoundments in Brazil's Amazon-Cerrado Agricultural Frontier

    Science.gov (United States)

    Solvik, K.; Macedo, M.; Graesser, J.; Lathuilliere, M. J.

    2017-12-01

    Large-scale agriculture and cattle ranching in Brazil has driving the creation of tens of thousands of small stream impoundments to provide water for crops and livestock. These impoundments are a source of methane emissions and have significant impacts on stream temperature, connectivity, and water use over a large region. Due to their large numbers and small size, they are difficult to map using conventional methods. Here, we present a two-stage object-based supervised classification methodology for identifying man-made impoundments in Brazil. First, in Google Earth Engine pixels are classified as water or non-water using satellite data and HydroSHEDS products as predictors. Second, using Python's scikit-learn and scikit-image modules the water objects are classified as man-made or natural based on a variety of shape and spectral properties. Both classifications are performed by a random forest classifier. Training data is acquired by visually identifying impoundments and natural water bodies using high resolution satellite imagery from Google Earth.This methodology was applied to the state of Mato Grosso using a cloud-free mosaic of Sentinel 1 (10m resolution) radar and Sentinel 2 (10-20m) multispectral data acquired during the 2016 dry season. Independent test accuracy was estimated at 95% for the first stage and 93% for the second. We identified 54,294 man-made impoundments in Mato Grosso in 2016. The methodology is generalizable to other high resolution satellite data and has been tested on Landsat 5 and 8 imagery. Applying the same approach to Landsat 8 images (30 m), we identified 35,707 impoundments in the 2015 dry season. The difference in number is likely because the coarser-scale imagery fails to detect small (work will apply this approach to satellite time series for the entire Amazon-Cerrado frontier, allowing us to track changes in the number, size, and distribution of man-made impoundments. Automated impoundment mapping over large areas may help with

  6. Task 12: Laser cleaning of contaminated painted surfaces. Semi-annual report, April 1, 1996--September 30, 1996

    International Nuclear Information System (INIS)

    Grisanti, A.A.; Hassett, D.J.

    1997-01-01

    Paint contaminated with radionuclides and other hazardous materials is common in Department of Energy (DOE) facilities. Facility decommissioning and decontamination requires the removal of contaminated paint. Paint removal technologies include laser- and abrasive-based systems. F2 Associates are utilizing a pulsed-repetition CO 2 laser that produces a 2.5-cm x 2.5-cm beam which can be scanned across a 30- x 100-cm raster and, when placed on a robot, can be designed to clean any surface that the robot can be programmed to follow. Causing little or no damage to the substrate (concrete, steel, etc.), the laser ablates the material to be removed from a given surface. Ablated material is then pulled into a filtration and collection (VAC-PAC) system to prevent the hazardous substances from entering into the atmosphere. The VAC-PAC system deposits the ablated material into waste drums which may be removed from the system without compromising the integrity of the seal, allowing a new drum to be set up for collection without leakage of the ablated material into the atmosphere

  7. Microcrustaceans (Branchipoda and Copepoda) of Wetland Impoundments on the Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    DeBiase, Adrienne E; Taylor, Barbara E

    2005-09-21

    The United States Department of Energy’s Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders, larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.

  8. Characterization of transient groundwater flow through a high arch dam foundation during reservoir impounding

    Directory of Open Access Journals (Sweden)

    Yifeng Chen

    2016-08-01

    Full Text Available Even though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world's highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks, which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality (PVI method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results.

  9. Recovery of the Three-Gorges Reservoir Impoundment Signal from ICESat altimetry and GRACE

    Science.gov (United States)

    Carabajal, C. C.; Boy, J.; Luthcke, S. B.; Harding, D. J.; Rowlands, D. D.; Lemoine, F. G.

    2006-12-01

    The Three Gorges Dam along the Yangtze River in China is one of the largest dams in the world. The water impoundment of the Three-Gorges Reservoir started in June 2003, and the volume of water will continuously increase up to about 40 km3 in 2009, over a length of about 600 km. Although water-level changes along the Yangtze River and the Three Gorges Reservoir are measured by in situ water gauges, access to these data can be quite difficult. Estimates of inland water height and extent can also be recovered from altimetry measurements performed from satellite platforms, such as those acquired by the Geoscience laser Altimetry System (GLAS) on board the Ice, Cloud and Land Elevation Satellite (ICESat). ICESat has produced a comprehensive, highly precise, set of along-track elevation measurements, every three months since its launch in 2003, which intersect the Yangtze River along its East-West extent. In addition, the water impoundment of major artificial reservoirs induces variations of global geodetic quantities, such as the gravity field and Earth rotation (Chao, 1995, Boy & Chao, 2002). Water level changes within the reservoir are compared to GRACE (Gravity Recovery And Climate Experiment) recovered water mass changes. In addition, we compare the GRACE observations of mass change in the Yangtze region to hydrological changes computed from different global soil-moisture and snow models, such as GLDAS (Global Land Data Assimilation System).

  10. Geometrical and hydrogeological impact on the behaviour of deep-seated rock slides during reservoir impoundment

    Science.gov (United States)

    Lechner, Heidrun; Zangerl, Christian

    2015-04-01

    Given that there are still uncertainties regarding the deformation and failure mechanisms of deep-seated rock slides this study concentrates on key factors that influence the behaviour of rock slides in the surrounding of reservoirs. The focus is placed on the slope geometry, hydrogeology and kinematics. Based on numerous generic rock slide models the impacts of the (i) rock slide geometry, (ii) reservoir impoundment and level fluctuations, (iii) seepage and buoyancy forces and (iv) hydraulic conductivity of the rock slide mass and the basal shear zone are examined using limit equilibrium approaches. The geometry of many deep-seated rock slides in metamorphic rocks is often influenced by geological structures, e.g. fault zones, joints, foliation, bedding planes and others. With downslope displacement the rock slide undergoes a change in shape. Several observed rock slides in an advanced stage show a convex, bulge-like topography at the foot of the slope and a concave topography in the middle to upper part. Especially, the situation of the slope toe plays an important role for stability. A potentially critical situation can result from a partially submerged flat slope toe because the uplift due to water pressure destabilizes the rock slide. Furthermore, it is essential if the basal shear zone daylights at the foot of the slope or encounters alluvial or glacial deposits at the bottom of the valley, the latter having a buttressing effect. In this study generic rock slide models with a shear zone outcropping at the slope toe are established and systematically analysed using limit equilibrium calculations. Two different kinematic types are modelled: (i) a translational or planar and (ii) a rotational movement behaviour. Questions concerning the impact of buoyancy and pore pressure forces that develop during first time impoundment are of key interest. Given that an adverse effect on the rock slide stability is expected due to reservoir impoundment the extent of

  11. Use of special oedometer tests for the remediation of large uranium mill tailings impoundments at Wismut, Germany

    International Nuclear Information System (INIS)

    Barnekow, U.; Paul, M.

    2002-01-01

    The paper presents the use of recently developed special oedometer tests for designing the remediation of large uranium tailings ponds at WISMUT, Germany. Uranium ore mining and milling in eastern Germany by the former Soviet-German WISMUT company lasted from 1946 to 1990. Wastes from the hydrometallurgical uranium extraction processes were discharged into large tailings impoundments covering a total area of 5.5 km 2 and containing about 150 x 10 6 m 3 of uranium mill tailings. Tailings pond remediation is ongoing by in-place decommissioning with dewatering by technical means. Geotechnical properties and the most suitable so-called non-linear finite strain consolidation behaviour of fine uranium mill tailings are described. Decommissioning techniques comprise, among others, interim covering of under consolidated fine tailings, contouring of tailings surfaces and final covering. Contouring, in particular, has a huge potential for optimization in terms of cost reduction. For contouring total settlement portions, the spatial distribution of differential settlement portions and the time-dependent settlement rates, especially of the cohesive fine uranium mill tailings are of critical importance. A new special oedometer KD 314 S has been developed to generate all the input data needed to derive the fundamental geotechnical relationships of void ratio vs. effective stress and of permeability coefficient vs. void ratio for consolidation calculations. Since December 1999 the new special oedometer KD 314 S has been working successfully on fine uranium mill tailings from both acid and from soda alkaline milling. Results coincide with non-linear finite strain consolidation theory. The geotechnical functions derived were used as input parameters for consolidation modelling. An example of the consolidation modelling on Helmsdorf tailings pond is presented. (author)

  12. Active microwave remote sensing research program plan. Recommendations of the Earth Resources Synthetic Aperture Radar Task Force. [application areas: vegetation canopies, surface water, surface morphology, rocks and soils, and man-made structures

    Science.gov (United States)

    1980-01-01

    A research program plan developed by the Office of Space and Terrestrial Applications to provide guidelines for a concentrated effort to improve the understanding of the measurement capabilities of active microwave imaging sensors, and to define the role of such sensors in future Earth observations programs is outlined. The focus of the planned activities is on renewable and non-renewable resources. Five general application areas are addressed: (1) vegetation canopies, (2) surface water, (3) surface morphology, (4) rocks and soils, and (5) man-made structures. Research tasks are described which, when accomplished, will clearly establish the measurement capabilities in each area, and provide the theoretical and empirical results needed to specify and justify satellite systems using imaging radar sensors for global observations.

  13. The use of artificial impoundments by two amphibian species in the Delaware Water Gap National Recreation Area

    Science.gov (United States)

    Julian, J.T.; Snyder, C.D.; Young, J.A.

    2006-01-01

    We compared breeding activity of Ambystoma maculatum (Spotted Salamander) and Rana sylvatica (Wood Frog) in artificial impoundments to patterns in natural wetlands over a three-year period in the Delaware Water Gap National Recreation Area. Rana sylvatica were 5.6 times more likely to use natural bodies of water for breeding than artificial impoundments, while A. maculatum were 2.7 times more likely to use natural bodies of water. Both species were approximately 9 times more likely to breed in fishless bodies of water than in waters with predatory fish. Ambystoma maculatum were 6 times more likely to breed in wetlands with more stable seasonal hydroperiods, while R. sylvatica were only 2 times more likely to do so. We conclude that the high likelihood of fish presence in impoundments was the primary explanation for why both species were less likely to use impoundments than natural wetlands, while the tendency of A. maculatum to avoid natural wetlands with shorter hydroperiods explained why differences in use between pond types was more pronounced for R. sylvatica.

  14. Analysis of spatial distribution and inventory of radioactivity within the uranium mill tailings impoundment

    Directory of Open Access Journals (Sweden)

    D. O. Bugai

    2015-10-01

    Full Text Available Results are presented of the characterization of radioactivity inventory of Zapadnoe uranium mill tailings impoundment situated at Pridneprovsky Chemical Plant (PChP; Dneprodzerzhinsk, Ukraine. Analyses of radioactivity data set based on analytical studies of core material from 15 characterization boreholes allowed significantly refining waste volume and radioactivity inventory estimates. Geostatistical analyses using variogram function have established that radioactivity distribution in Zapadnoe tailings is characterized by regular spatial correlation patterns. Ordinary kriging method was applied to assess distribution of radioactivity in 3D. Results of statistical analyses suggest significant redistribution of uranium in the dissolved form in the residues (presumably due to water infiltration process. The developed structural model for radioactivity distribution is used for further risk assessment analyses. Derived radioactivity correlation scales can be used for optimization of sample collection when characterizing the PChP Site and similar contaminated sites elsewhere.

  15. Chlorophyll Detection and Mapping of Shallow Water Impoundments Using Image Spectrometry

    International Nuclear Information System (INIS)

    Artigas, F.; Pechmann, I.; Marti, A.; Yao, N.; Pechmann, I.

    2008-01-01

    There exists a common perception that chlorophyll a concentrations in tidal coastal waters are unsuitable to be captured by remote sensing techniques because of high water turbidity. In this study, we use band index measurements to separate active chlorophyll pigments from other constituents in the water. Published single- and multiband spectral indices are used to establish a relationship between algal chlorophyll concentration and reflectance data. We find an index which is suitable to map chlorophyll gradients in the impoundments, ditches, and associated waterways of the Hackensack Meadow lands (NJ, USA). The resulting images clearly depict the spatial distribution of plant pigments and their relationship with the biological conditions of the waters in the estuary. Since these biological conditions are often determined by land usage, the methods in this paper provide a simple tool to address water quality management issues in fragmented urban estuaries.

  16. Effects of hydrologic variables on rock riprap design for uranium tailings impoundments

    International Nuclear Information System (INIS)

    Walters, W.H.; Skaggs, R.L.

    1985-01-01

    Pacific Northwest Laboratory is studying the mitigation of erosion of earthen radon suppression covers for uranium tailings impoundments. Because the covers will require erosion protection for upwards of 1000 years, rock riprap (armoring) has been proposed as the primary protection method. This study investigates the sensitivity of riprap design procedures to extreme flood events that can generate high flow velocities and shear stresses. The study uses two decommissioned tailings sites (Grand Junction and Slick Rock, Colorado) as case studies to evaluate the sensitivity of design rock size with respect to variables such as flood discharge, side slope, specific gravity, safety factor, and channel roughness. The results indicate that design rock size can vary significantly for different design procedures. Other significant results indicate that embankment side slopes of about 4H:1V are optimum for rock riprap and that the use of rock material with specific gravities less than about 2.50 may prove too costly

  17. A model for evaluating effects of climate, water availability, and water management on wetland impoundments--a case study on Bowdoin, Long Lake, and Sand Lake National Wildlife Refuges

    Science.gov (United States)

    Tangen, Brian A.; Gleason, Robert A.; Stamm, John F.

    2013-01-01

    Many wetland impoundments managed by the U.S. Fish and Wildlife Service (USFWS) National Wildlife Refuge System throughout the northern Great Plains rely on rivers as a primary water source. A large number of these impoundments currently are being stressed from changes in water supplies and quality, and these problems are forecast to worsen because of projected changes to climate and land use. For example, many managed wetlands in arid regions have become degraded owing to the long-term accumulation of salts and increased salinity associated with evapotranspiration. A primary goal of the USFWS is to provide aquatic habitats for a diversity of waterbirds; thus, wetland managers would benefit from a tool that facilitates evaluation of wetland habitat quality in response to current and anticipated impacts of altered hydrology and salt balances caused by factors such as climate change, water availability, and management actions. A spreadsheet model that simulates the overall water and salinity balance (WSB model) of managed wetland impoundments is presented. The WSB model depicts various habitat metrics, such as water depth, salinity, and surface areas (inundated, dry), which can be used to evaluate alternative management actions under various water-availability and climate scenarios. The WSB model uses widely available spreadsheet software, is relatively simple to use, relies on widely available inputs, and is readily adaptable to specific locations. The WSB model was validated using data from three National Wildlife Refuges with direct and indirect connections to water resources associated with rivers, and common data limitations are highlighted. The WSB model also was used to conduct simulations based on hypothetical climate and management scenarios to demonstrate the utility of the model for evaluating alternative management strategies and climate futures. The WSB model worked well across a range of National Wildlife Refuges and could be a valuable tool for USFWS

  18. Fishers' knowledge identifies environmental changes and fish abundance trends in impounded tropical rivers.

    Science.gov (United States)

    Hallwass, Gustavo; Lopes, Priscila F; Juras, Anastácio A; Silvano, Renato A M

    2013-03-01

    The long-term impacts of large hydroelectric dams on small-scale fisheries in tropical rivers are poorly known. A promising way to investigate such impacts is to compare and integrate the local ecological knowledge (LEK) of resource users with biological data for the same region. We analyzed the accuracy of fishers' LEK to investigate fisheries dynamics and environmental changes in the Lower Tocantins River (Brazilian Amazon) downstream from a large dam. We estimated fishers' LEK through interviews with 300 fishers in nine villages and collected data on 601 fish landings in five of these villages, 22 years after the dam's establishment (2006-2008). We compared these two databases with each other and with data on fish landings from before the dam's establishment (1981) gathered from the literature. The data obtained based on the fishers' LEK (interviews) and from fisheries agreed regarding the primary fish species caught, the most commonly used type of fishing gear (gill nets) and even the most often used gill net mesh sizes but disagreed regarding seasonal fish abundance. According to the interviewed fishers, the primary environmental changes that occurred after the impoundment were an overall decrease in fish abundance, an increase in the abundance of some fish species and, possibly, the local extinction of a commercial fish species (Semaprochilodus brama). These changes were corroborated by comparing fish landings sampled before and 22 years after the impoundment, which indicated changes in the composition of fish landings and a decrease in the total annual fish production. Our results reinforce the hypothesis that large dams may adversely affect small-scale fisheries downstream and establish a feasible approach for applying fishers' LEK to fisheries management, especially in regions with a low research capacity.

  19. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects.

    Science.gov (United States)

    Cao, Liu; Wang, Ying; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Zheng, Dingchang

    2017-01-01

    The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF) magnetic stimulation on surface electromyography (SEMG) signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body) with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects). The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject's deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS), median frequency (MDF), and sample entropy (SampEn), were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant ( p 0.05). In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p < 0.001) and MDF and SampEn were significantly smaller (all p < 0.001).

  20. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Liu Cao

    2017-01-01

    Full Text Available The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF magnetic stimulation on surface electromyography (SEMG signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject’s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS, median frequency (MDF, and sample entropy (SampEn, were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05. In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p<0.001 and MDF and SampEn were significantly smaller (all p<0.001.

  1. [Influence of 175-m-impoundment in Three Gorges Reservoir area on the food web energy sources of main commercial fishes in backwater area of xiaojiang River].

    Science.gov (United States)

    Li, Bin; Wang, Zhi-Jian; Yue, Xing-Jian; Wang, Yong-Ming; Jin, Li; Zhang, Yao-Guang

    2013-06-01

    The impoundment in the Three Gorges Reservoir Area (TGRA) was first reached 175 m in 2010. To approach the influence of this impoundment on the food web energy sources of fishes in the tributaries of TRGA, an analysis was made on the food web energy sources of seven economically important fishes (Carassius auratus, Cyprinus carpio, Silurus asotus, Culter mongolicus mongolicus, Mystus macropterus, Pelteobagrus vachelli, and Pelteobagrus nitidus) in the backwater area of Xiaojiang River by using stable isotope method in combining with IsoSource Model. The results showed that before this impoundment (July 2010), microalgae were the main energy sources for the seven species. After this impoundment (December 2010), the contribution ratio of the microalgae decreased somewhat, while the relative contribution of terrestrial C4 plants had an obvious increase. Especially for crucian carp (C. auratus) and catfish (S. asotus), the contribution rate of the C4 plants reached 38-54% and 32-50%, respectively. After the impoundment, at least 30% of the energy resources of these two fishes were come from terrestrial C4 plants, suggesting that the impoundment in TGRA increased the contribution rate of exogenous terrestrial C4 plants as the energy sources of fishes.

  2. Arsenic mobility from anthropogenic impoundment sediments - Consequences of contamination to biota, water and sediments, Posa, Eastern Slovakia

    Energy Technology Data Exchange (ETDEWEB)

    Hiller, E.; Jurkovic, L.; Kordik, J.; Slaninka, I.; Jankular, M.; Majzlan, J.; Gottlicher, J.; Steininger, R. [Geological Survey of Slovak Republic, Bratislava (Slovakia). Dept. of Environmental Geochemistry

    2009-11-15

    An impoundment located near the village of Posa, Slovakia, is a significant source of contamination with As originating from the deposited coal fly-ash. Waters penetrating the impoundment are enriched in As and other potentially toxic elements. As a consequence of the contamination, the Kyjov Brook and the Ondava River have been extensively polluted. The mobility and solid-state partitioning of As in the impoundment material and stream sediments were investigated using column leaching and batch extraction tests, and a five-step sequential extraction procedure. Moreover, to investigate the bioavailability of As, two native plant species (Typha latifolia, or cattail, and Phragmites australis, or common reed) growing at the site were collected and analyzed. The As concentrations in representative sediment and water samples ranged from 36.3 to 3210 mg/kg and from 4.05 to 613 {mu} g/L, respectively, both being many times above the background levels. Although a part of As was present in a readily soluble form (6.6%), the majority of As was mainly associated with Fe and Mn oxides (37%) and residual phases (51%). Combined results of the column leaching, batch extraction, and sequential extraction tests, as well as mineralogical analysis, indicated that As mobilisation potential from the sediments is likely controlled by Fe, Al and Mn oxides, and by pH. There was no influence of various anions (PO{sub 4}{sup 3-}, SO{sub 4}{sup 2-}, NO{sup 3-}, Cl{sup -} and HCO{sub 3}{sup -}) on As mobility when present in aqueous solution at concentrations analogous to those in the water of the Kyjov Brook. Plants growing in the impoundment had As concentrations 10-100 times greater than did the same plants growing in a relatively non-polluted area.

  3. Low-level radioactive waste disposal in the USA - Use of mill tailings impoundments as a new policy option

    International Nuclear Information System (INIS)

    Farrell, C.W.

    2006-01-01

    Disposal of low-level radioactive waste (LLW) in the United States is facing severe and immediate capacity limitations. Seemingly intractable regulatory and jurisdictional conflicts make establishment of new LLW disposal sites effectively impossible. Uranium mill tailings impoundments constructed at conventional uranium open-cast and underground mines could offer approximately 40 to 80+ million tons of disposal capacity for low activity radioactive waste. Such impoundments would provide an enhanced, high level of environmental and health and safety protection for the direct disposal of depleted uranium, special nuclear material, technologically-enhanced, naturally-occurring radioactive material (TENORM) and mixed waste. Many waste streams, such as TENORM and decommissioning rubble, will be high-volume, low activity materials and ideally suited for disposal in such structures. Materials in a given decay chain with a total activity from all radionuclides present of ∼820 Bq/g (2.22 x 10 -08 Ci/g) with no single radionuclide present in an activity greater than ∼104 Bq/g (2,800 pCi/g) should be acceptable for disposal. Materials of this type could be accepted without any site-specific dose modelling, so long as the total activity of the tailings impoundment not exceed its design capacity (generally 82 x 10 07 Bq/metric tonne) (0.020 Ci/short ton) and the cover design requirements to limit radon releases are satisfied. This paper provides background on US LLW disposal regulations, examines LLW disposal options under active consideration by the US Environmental Protection Agency and Department of Energy, develops generic waste acceptance criteria and identifies policy needs for federal and state governments to facilitate use of uranium mill tailings impoundments for LLW disposal. (author)

  4. Evaluation of behaviors of earth and rockfill dams during construction and initial impounding using instrumentation data and numerical modeling

    Directory of Open Access Journals (Sweden)

    Mohammad Rashidi

    2017-08-01

    Full Text Available In this study, the behavior of Gavoshan dam was evaluated during construction and the first impounding. A two-dimensional (2D numerical analysis was conducted based on a finite difference method on the largest cross-section of the dam using the results of instrument measurements and back analysis. These evaluations will be completed in the case that back analysis is carried out in order to control the degree of the accuracy and the level of confidence of the measured behavior since each of the measurements could be controlled by comparing it to the result obtained from the numerical model. Following that, by comparing the results of the numerical analysis with the measured values, it is indicated that there is a proper consistency between these two values. Moreover, it was observed that the dam performance was suitable regarding the induced pore water pressure, the pore water pressure ratio ru, settlement, induced stresses, arching degree, and hydraulic fracturing probability during the construction and initial impounding periods. The results demonstrated that the maximum settlement of the core was 238 cm at the end of construction. In the following 6 years after construction (initial impounding and exploitation period, the accumulative settlement of the dam was 270 cm. It is clear that 88% of the total settlement of the dam took place during dam construction. The reason is that the clay core was smashed in the wet side, i.e. the optimum moisture content. Whereas the average curving ratio was 0.64 during dam construction; at the end of the initial impounding, the maximum amount of curving ratio in the upstream was 0.81, and the minimum (critical amount in the downstream was 0.52. It was also concluded that this dam is safe in comparison with the behaviors of other similar dams in the world.

  5. Hypersalinity reduces the risk of cyanide toxicosis to insectivorous bats interacting with wastewater impoundments at gold mines.

    Science.gov (United States)

    Griffiths, Stephen R; Donato, David B; Lumsden, Linda F; Coulson, Graeme

    2014-01-01

    Wildlife and livestock that ingest bioavailable cyanide compounds in gold mining tailings dams are known to experience cyanide toxicosis. Elevated levels of salinity in open impoundments have been shown to prevent wildlife cyanide toxicosis by reducing drinking and foraging. This finding appears to be consistent for diurnal wildlife interacting with open impoundments, however the risks to nocturnal wildlife of cyanide exposure are unknown. We investigated the activity of insectivorous bats in the airspace above both fresh (potable to wildlife) and saline water bodies at two gold mines in the goldfields of Western Australian. During this study, cyanide-bearing solutions stored in open impoundments at both mine sites were hypersaline (range=57,000-295,000 mg/L total dissolved solids (TDS)), well above known physiological tolerance of any terrestrial vertebrate. Bats used the airspace above each water body monitored, but were more active at fresh than saline water bodies. In addition, considerably more terminal echolocation buzz calls were recorded in the airspace above fresh than saline water bodies at both mine sites. However, it was not possible to determine whether these buzz calls corresponded to foraging or drinking bouts. No drinking bouts were observed in 33 h of thermal video footage recorded at one hypersaline tailings dam, suggesting that this water is not used for drinking. There is no information on salinity tolerances of bats, but it could be assumed that bats would not tolerate salinity in drinking water at concentrations greater than those documented as toxic for saline-adapted terrestrial wildlife. Therefore, when managing wastewater impoundments at gold mines to avoid wildlife mortalities, adopting a precautionary principle, bats are unlikely to drink solutions at salinity levels ≥50,000 mg/L TDS. © 2013 Published by Elsevier Inc.

  6. Modulation of Extreme Flood Levels by Impoundment Significantly Offset by Floodplain Loss Downstream of the Three Gorges Dam

    Science.gov (United States)

    Mei, Xuefei; Dai, Zhijun; Darby, Stephen E.; Gao, Shu; Wang, Jie; Jiang, Weiguo

    2018-04-01

    River flooding—the world's most significant natural hazard—is likely to increase under anthropogenic climate change. Most large rivers have been regulated by damming, but the extent to which these impoundments can mitigate extreme flooding remains uncertain. Here the catastrophic 2016 flood on the Changjiang River is first analyzed to assess the effects of both the Changjiang's reservoir cascade and the Three Gorges Dam (TGD), the world's largest hydraulic engineering project on downstream flood discharge and water levels. We show that the Changjiang's reservoir cascade impounded over 30.0 × 103 m3/s of flow at the peak of the flood on 25 July 2016, preventing the occurrence of what would otherwise have been the second largest flood ever recorded in the reach downstream of the TGD. Half of this flood water storage was retained by the TGD alone, meaning that impoundment by the TGD reduced peak water levels at the Datong hydrometric station (on 25 July) by 1.47 m, compared to pre-TGD conditions. However, downstream morphological changes, in particular, extensive erosion of the natural floodplain, offset this reduction in water level by 0.22 m, so that the full beneficial impact of floodwater retention by the TGD was not fully realized. Our results highlight how morphological adjustments downstream of large dams may inhibit their full potential to mitigate extreme flood risk.

  7. Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

    International Nuclear Information System (INIS)

    Campbell, C.E.; Knoechel, R.; Copeman, D.

    1998-01-01

    An 11-year study of the zooplankton community in Cat Arm Hydroelectric Reservoir in Newfoundland was conducted to assess long-term zooplankton community dynamics in a subarctic system. Zooplankton biomass and species compositions were monitored from 1983 to 1993. The monitoring program documented the trophic evolution of the Cat Arm system as it changed from a shallow lake with short water retention time to a deep reservoir with a much lower flushing rate. Zooplankton biomass increased approximately 19-fold in the oligotrophic hydroelectric reservoir following impoundment in 1984, relative to biomass in the preexisting lake. During the first three years of impoundment, there were no increases in either phytoplankton biomass or primary productivity. Natality of the dominant cladoceran (Daphnia catawba) did not increase. Summer water retention time increased from pre-impoundment levels of 4 days in 1983 to 338 days in 1993. The study showed that zooplankton biomass was greatly correlated with water retention time, and showed no major correlation with phytoplankton biomass, primary productivity, nutrient concentrations, pH, colour, or epilimnetic temperature. It was concluded that changes in the zooplankton community in the hydroelectric reservoir were a result of decreases in losses due to washout. 41 refs., 2 tabs., 6 figs

  8. [Effects of Three Gorges Reservoir impoundment on the wetland ecosystem service value of Dongting Lake, South-central China].

    Science.gov (United States)

    Li, Jing-Bao; Dai, Yong; Yin, Ri-Xin; Yang, Yan; Li, Yu-dan; Wang, Ke-ying

    2013-03-01

    Based on the field investigation and measurement, and by using the monetary method, this paper estimated the wetland ecosystem service value of Dongting Lake before and after the impoundment of Three Gorges Reservoir (in 1996 and 2010, respectively). After the impoundment, the total ecosystem service value increased from 156.69x10(8) yuan in 1996 to 177.11x10(8) yuan in 2010. The main services value in 1996 was in the order of flood storage and regulation > water storage and supply > air regulation > scientific research and education, while that in 2010 was leisure tourism > shipping transportation > air regulation > water storage and supply. In the total service value of the wetland ecosystem, the direct value associated with water decreased from 110. 85x10(8) in 1996 to 27.47x10(8) in 2010, with a decrement of 75.2%. Though the proportion of the direct value in the production and supply of material products had somewhat increase, the indirect value in ecological environment regulation and maintenance and in culture and society still maintained at about 80% of the total value. In addition to climate factors, the impoundment of Three Gorges Reservoir and the reduction of water and sediment from Yangtze River to the Lake were the crucial reasons leading to the changes of the wetland ecosystem service value of Dongting Lake.

  9. Effect of fishing effort on catch rate and catchability of largemouth bass in small impoundments

    Science.gov (United States)

    Wegener, M. G.; Schramm, Harold; Neal, J. W.; Gerard, P.D.

    2018-01-01

    Largemouth bass Micropterus salmoides (Lacepède) catch rates decline with sustained fishing effort, even without harvest. It is unclear why declines in catch rate occur, and little research has been directed at how to improve catch rate. Learning has been proposed as a reason for declining catch rate, but has never been tested on largemouth bass. If catch rate declines because fish learn to avoid lures, periods of no fishing could be a management tool for increasing catch rate. In this study, six small impoundments with established fish populations were fished for two May to October fishing seasons to evaluate the effect of fishing effort on catch rate. Closed seasons were implemented to test whether a 2‐month period of no fishing improved catch rates and to determine whether conditioning from factors other than being captured reduced catch rate. Mixed‐model analysis indicated catch rate and catchability declined throughout the fishing season. Catch rate and catchability increased after a 2‐month closure but soon declined to the lowest levels of the fishing season. These changes in catch rate and catchability support the conclusion of learned angler avoidance, but sustained catchability of fish not previously caught does not support that associative or social learning affected catchability.

  10. Evidence for serial discontinuity in the fish community of a heavily impounded river

    Science.gov (United States)

    Miranda, Leandro E.; Dembkowski, D.J.

    2016-01-01

    In the Tennessee River, USA, we examined lengthwise patterns in fish community structure and species richness within and among nine reservoirs organized in sequence and connected through navigational locks. Within reservoirs, the riverine, transition and lacustrine zones supported distinct, although overlapping, nearshore fish assemblages; differences were also reflected in measures of species richness. Spatial patterns were most apparent for rheophilic species, which increased in species richness and representation upstream within each reservoir and downstream across the chain of reservoirs. This pattern resembled a sawtooth wave, with the amplitude of the wave peaking in the riverine zone below each dam, and progressively higher wave amplitude developing downstream in the reservoir chain. The observed sawtooth pattern supports the serial discontinuity concept in that the continuity of the riverine fish community is interrupted by the lacustrine conditions created behind each dam. Upstream within each reservoir, and downstream in the chain of reservoirs, habitat characteristics become more riverine. To promote sustainability of rheophilic fishes and maintain biodiversity in impounded rivers, conservation plans could emphasize maintenance and preservation of riverine environments of the reservoir's upper reaches, while remaining cognizant of the broader basin trends that provide opportunities for a lengthwise array of conservation and management policy. 

  11. Survivability of ancient man-made earthen mounds: implications for uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Lindsey, C.G.; Mishima, J.; King, S.E.; Walters, W.H.

    1983-06-01

    As part of a study for the Nuclear Regulatory Commission (NRC), the Pacific Northwest Laboratory (PNL) is investigating long-term stabilization techniques for uranium mill impoundments. Part of this investigation involves the design of a rock armoring blanket (riprap) to mitigate wind and water erosion of the underlying soil cover, which in turn prevents exposure of the tailings to the environment. However, the need for the armoring blanket, as well as the blanket's effectiveness, depends on the stability of the underlying soil cap (radon suppression cover) and on the tailings themselves. Compelling evidence in archaeological records suggests that large man-made earthen structures can remain sound and intact for time periods comparable to those required for the stabilization of the tailings piles if properly constructed. We present archaeological evidence on the existence and survivability of man-made earthen and rock structures through specific examples of such structures from around the world. We also review factors contributing to their survival or destruction and address the influence of climate, building materials, and construction techniques on survivability

  12. Methane Oxidation and Molecular Characterization of Methanotrophs from a Former Mercury Mine Impoundment

    Directory of Open Access Journals (Sweden)

    Shaun M. Baesman

    2015-06-01

    Full Text Available The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5 medium via methane oxidation.

  13. Methane oxidation and molecular characterization of methanotrophs from a former mercury mine impoundment

    Science.gov (United States)

    Baesman, Shaun; Miller, Laurence G.; Wei, Jeremy H.; Cho, Yirang; Matys, Emily D.; Summons, Roger E.; Welander, Paula V.; Oremland, Ronald S.

    2015-01-01

    The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5) medium via methane oxidation.

  14. The Effect of Zebra Mussels on Algal Community Structure in an Impounded River System

    Science.gov (United States)

    Trumble, A. F.; Luttenton, M.

    2005-05-01

    The zebra mussel, Dreissena polymorpha, invaded the Great Lakes Region in the mid 1980's, and subsequently colonized inland lakes and coastal river systems through secondary invasions. The Muskegon River below Croton Dam was colonized by zebra mussels in 2000 following their introduction into Croton impoundment in the late 1990's. No zebra mussels were found below Croton Dam in 1999 but had increased to 25,000 m-2 by 2001. We examined the affect of zebra mussels on epilithic periphyton communities by comparing plots that were and were not colonized by zebra mussels. Chlorophyll a increased in both treatments over time but was significantly higher in control plots than in zebra mussel plots. The concentration of chlorophyll a in the control plots increased from 14 µgcm-2 to 26 µgcm-2 and the concentration in the zebra mussel plots started at 12 µgcm-2, peaked at 19 µgcm-2, and then decreased to 15 µgcm-2 over a 6 week period. In a related experiment using artificial streams, chlorophyll a increased with increasing zebra mussel density, but differences were not significant. The different trends observed between the two experiments may be explained in part by arthropod invertebrates associated with zebra mussel populations.

  15. Quantifying downstream impacts of impoundment on flow regime and channel planform, lower Trinity River, Texas

    Science.gov (United States)

    Wellmeyer, Jessica L.; Slattery, Michael C.; Phillips, Jonathan D.

    2005-07-01

    As human population worldwide has grown, so has interest in harnessing and manipulating the flow of water for the benefit of humans. The Trinity River of eastern Texas is one such watershed greatly impacted by engineering and urbanization. Draining the Dallas-Fort Worth metroplex, just under 30 reservoirs are in operation in the basin, regulating flow while containing public supplies, supporting recreation, and providing flood control. Lake Livingston is the lowest, as well as largest, reservoir in the basin, a mere 95 km above the Trinity's outlet near Galveston Bay. This study seeks to describe and quantify channel activity and flow regime, identifying effects of the 1968 closure of Livingston dam. Using historic daily and peak discharge data from USGS gauging stations, flow duration curves are constructed, identifying pre- and post-dam flow conditions. A digital historic photo archive was also constructed using six sets of aerial photographs spanning from 1938 to 1995, and three measures of channel activity applied using a GIS. Results show no changes in high flow conditions following impoundment, while low flows are elevated. However, the entire post-dam period is characterized by significantly higher rainfall, which may be obscuring the full impact of flow regulation. Channel activity rates do not indicate a more stabilized planform following dam closure; rather they suggest that the Trinity River is adjusting itself to the stress of Livingston dam in a slow, gradual process that may not be apparent in a modern time scale.

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

    Science.gov (United States)

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

    2013-01-01

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

  17. Automated detection of submerged navigational obstructions in freshwater impoundments with hull mounted sidescan sonar

    Science.gov (United States)

    Morris, Phillip A.

    The prevalence of low-cost side scanning sonar systems mounted on small recreational vessels has created improved opportunities to identify and map submerged navigational hazards in freshwater impoundments. However, these economical sensors also present unique challenges for automated techniques. This research explores related literature in automated sonar imagery processing and mapping technology, proposes and implements a framework derived from these sources, and evaluates the approach with video collected from a recreational grade sonar system. Image analysis techniques including optical character recognition and an unsupervised computer automated detection (CAD) algorithm are employed to extract the transducer GPS coordinates and slant range distance of objects protruding from the lake bottom. The retrieved information is formatted for inclusion into a spatial mapping model. Specific attributes of the sonar sensors are modeled such that probability profiles may be projected onto a three dimensional gridded map. These profiles are computed from multiple points of view as sonar traces crisscross or come near each other. As lake levels fluctuate over time so do the elevation points of view. With each sonar record, the probability of a hazard existing at certain elevations at the respective grid points is updated with Bayesian mechanics. As reinforcing data is collected, the confidence of the map improves. Given a lake's current elevation and a vessel draft, a final generated map can identify areas of the lake that have a high probability of containing hazards that threaten navigation. The approach is implemented in C/C++ utilizing OpenCV, Tesseract OCR, and QGIS open source software and evaluated in a designated test area at Lake Lavon, Collin County, Texas.

  18. Impoundment effects in the population of Auchenipterus osteomystax (Siluriformes: Auchenipteridae: a Neotropical reservoir case

    Directory of Open Access Journals (Sweden)

    Elcio Barili

    2012-06-01

    Full Text Available New impoundments provide opportunities to check whether species that present enough feeding flexibility in natural conditions may take advantage of this situation and, without reproductive restriction, can occupy the most conspicuous habitat in a large reservoir (open areas and present higher success in the colonization of the new environment. We examined variations in the abundance and feeding of A. osteomystax in two environments, one natural (Sinha Mariana floodplain lake and one dammed (Manso Reservoir, during two periods: the first year after the filling phase and three years later. Our goal was to evaluate the occupation of the new hábitat (Manso Reservoir, by this species, as well as to test the hypothesis that in the reservoir, unlike the natural environment, there are remarkable changes in diet between the periods. Fish were sampled monthly in the floodplain lake and in the reservoir during two annual periods using gillnets. To evaluate the differences in abundance of A. osteomystax we employed the Kruskal -Wallis test, and the diet analysis was carried out using frequency of occurrence and volumetric methods. Temporal differences in the diet were tested by Kruskal-Wallis test using the scores from a detrended correspondence analysis. A. osteomystax was significantly more abundant in the floodplain lake, where the captures were higher than in the reservoir in almost all months analyzed, and significant variations in abundance between the two periods were not recorded in either the reservoir or the floodplain lake. The diet variation between the two periods, which had a time lag of three years between them, was much less pronounced in the natural environment, where the resource availability is essentially regulated by seasonality. Thus, our hypothesis was accepted; that is, the interannual variations in the diet of A. osteomystax are more relevant in an artificial environment than in a natural one. Rev. Biol. Trop. 60 (2: 699-708. Epub

  19. Sharptooth catfish shows its metal: a case study of metal contamination at two impoundments in the Olifants River, Limpopo river system, South Africa.

    Science.gov (United States)

    Jooste, Antoinette; Marr, Sean M; Addo-Bediako, Abraham; Luus-Powell, Wilmien J

    2015-02-01

    Clarias gariepinus is increasing in importance as a global aquaculture species with a 100 fold increase in production over the past decade but this species still remains one of the most important wild harvested freshwater food fish throughout rural Africa. However, this species has been shown to accumulate metals from contaminated inland waters. In this paper, the metal concentrations in muscle tissue of C. gariepinus from two main-stem impoundments in the Olifants River, Limpopo Basin, were measured and a desktop risk assessment based on the US-EPA methodology completed to evaluate whether long-term consumption of C. gariepinus from these impoundments may pose a health risk to rural communities. Our results show that metals are accumulating in the muscle tissue of C. gariepinus and have appeared to have increased in the last two decades. Risk assessment generated Hazard quotients (HQ) greater than 1 indicate that long term consumption of fish from these impoundments may cause adverse health impacts. We found that lead (HQ=9), antimony (HQ=14), cobalt (HQ=2) and chromium (HQ=1) at one impoundment and lead (HQ=2) at the other impoundment were above acceptable levels for weekly consumption of 150 g C. gariepinus muscle tissue. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Dynamics of dissolved organic matter in riverine sediments affected by weir impoundments: Production, benthic flux, and environmental implications.

    Science.gov (United States)

    Chen, Meilian; Kim, Sung-Han; Jung, Heon-Jae; Hyun, Jung-Ho; Choi, Jung Hyun; Lee, Hyo-Jin; Huh, In-Ae; Hur, Jin

    2017-09-15

    In order to understand the characteristics and dynamics of dissolved organic matter (DOM) in the sediment of rivers affected by impoundments, we examined the vertical profiles and the benthic fluxes of DOM in four different core sediments located at upstream sites of weirs in major rivers of South Korea. In three out of four sites, exponential accumulation of dissolved organic carbon (DOC) with depth was observed with the signature of seasonal variability. Except for the site displaying a below-detection limit of Fe(II), the general accumulation trends of DOC with depth was concurrent with the increases of Fe(II) and NH 4 + and the decrease of PO 4 3- , signifying a close linkage of the DOM dynamics with anaerobic respiration via iron reduction, an important early diagenesis pathway. The estimated benthic fluxes from the cores revealed that the sediments likely serve as DOC, chromophoric DOM (CDOM), and fluorescent DOM (FDOM) sources to the overlying water. The benthic effluxes based on DOC were comparable to the ranges previously reported in lake and coastal areas, and those of CDOM and FDOM showed even higher levels. These findings imply that impoundment-affected river systems would change the DOM composition of the overlying water, ultimately influencing the subsequent water treatment processes such as disinfection byproducts production and membrane fouling. A simple mass balance model indicated that the impoundment-affected river sediments may operate as a net carbon sink in the environments due to a greater extent of sedimentation compared to the estimated benthic efflux and sediment biological respiration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evaluating the effect of vehicle impoundment policy on illegal construction and demolition waste dumping: Israel as a case study.

    Science.gov (United States)

    Seror, Nissim; Hareli, Shlomo; Portnov, Boris A

    2014-08-01

    Construction and demolition (C&D) waste dumped alongside roads and in open areas is a major source of soil and underground water pollution. Since 2006, Israeli ministry for environmental protection enacted a policy of vehicle impoundment (VI) according to which track drivers caught while dumping C&D waste illegally have their vehicles impounded. The present study attempted to determine whether the VI policy was effective in increasing the waste hauling to authorized landfill sites, thus limiting the number of illegal unloads of C&D waste at unauthorized landfill sites and in open areas. During the study, changes in the ratio between the monthly amount of C&D waste brought to authorized landfills sites and the estimated total amount of C&D waste generated in different administrative districts of Israel were examined, before and after the enactment of the 2006 VI policy. Short questionnaires were also distributed among local track drivers in order to determine the degree of awareness about the policy in question and estimate its deterrence effects. According to the study's results, in the district of Haifa, in which the VI policy was stringently enacted, the ratio between C&D waste, dumped in authorized landfill sites, and the total amount of generated C&D waste, increased, on the average, from 20% in January 2004 to 35% in October 2009, with the effect attributed to the number of vehicle impoundments being highly statistically significant (t=2.324; p0.1). The analysis of the questionnaires, distributed among the local truck drivers further indicated that the changes observed in the district of Haifa are not coincident and appeared to be linked to the VI policy's enactment. In particular, 62% of the truck drivers, participated in the survey, were aware of the policy and 47% of them personally knew a driver whose vehicle was impounded. Furthermore, the drivers estimated the relative risk of being caught for unloading C&D waste in unauthorized sites, on the average, as

  2. Microcrustaceans (Branchiopoda and Copepoda) of Wetland Ponds and Impoundments on the Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Adrienne E. DeBiase; Barbara E. Taylor

    2005-09-21

    The United States Department of Energy's Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders, larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.

  3. Hydrologic Change during the Colonial Era of the United States: Beavers and the Energy Cost of Impoundments (Invited)

    Science.gov (United States)

    Green, M. B.; Bain, D. J.; Arrigo, J. S.; Duncan, J. M.; Kumar, S.; Parolari, A.; Salant, N.; Vorosmarty, C. J.; Aloysius, N. R.; Bray, E. N.; Ruffing, C. M.; Witherell, B. B.

    2009-12-01

    Europeans colonized North America in the early 17th century with intentions ranging between long-term inhabitation and quick extraction of resources for economic gain in Europe. Whatever the intentions, the colonists relied on the landscape for resources resulting in dramatic change to the forest and fur-bearing mammal population. We demonstrate that initial exploitation of North American forest and furs caused a substantial decrease in mean water residence time (τ) between 1600 and 1800 A.D. That loss, which regionally changed from 51 to 41 days, contrasts with conventional wisdom that humans tend to diminish variability in water resources by increasing storage capacity and thus increasing τ. The loss of τ resulted from over-hunted beaver for the hat market in Europe. Analysis suggests that colonial era demographics and economics did not allow human resource allocation to impoundment construction on a level matching the historic beaver effort. However, the τ appears to have regionally increased during the 19th century, suggesting that humans eventually began replacing the water storage lost with the beaver. The analysis highlights the energy cost of impounding water, which is likely to continue to be an important factor given the increasing need for stable water resources and finite energy resources.

  4. A Risk Assessment Approach to Manage Inundation of Elseya albagula Nests in Impounded Waters: A Win-Win Situation?

    Science.gov (United States)

    McDougall, A. J.; Espinoza, T.; Hollier, C.; Limpus, D. J.; Limpus, C. J.

    2015-03-01

    A risk assessment process was used to trial the impact of potential new operating rules on the frequency of nest inundation for the White-throated snapping turtle, Elseya albagula, in the impounded waters of the Burnett River, Queensland, Australia. The proposed operating rules would increase the barrage storage level during the turtle nesting season (May-July) and then would be allowed to reduce to a lower level for incubation for the rest of the year. These proposed operating rules reduce rates of nest inundation by altering water levels in the Ben Anderson Barrage impoundment of the Burnett River. The rules operate throughout the turtle reproductive period and concomitantly improve stability of littoral habitat and fishway operation. Additionally, the proposed rules are expected to have positive socio-economic benefits within the region. While regulated water resources will inherently have a number of negative environmental implications, these potential new operating rules have the capacity to benefit the environment while managing resources in a more sustainable manner. The operating rules have now been enacted in subordinate legislation and require the operator to maintain water levels to minimize turtle nest inundation.

  5. Conversion of a tailing impoundment to a freshwater reservoir, the Eagle Park Reservoir project, Climax Mine, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Romig, B.R.; Cupp, J.L.; Ford, R.C.

    1999-07-01

    The Climax Molybdenum Mine, located near Leadville, Colorado, is the site of a lengthy mining history spanning more than 80 years. In the 1960's, extraction of molybdenum from oxide ore located adjacent to the massive molybdenite sulfide deposit resulted in the construction of an earthen core dam to impound fine-grained oxide tailing in the Eagle River Valley. Through recognized value of water storage and reclamation opportunities, a tailing removal project was initiated in 1993 to convert the impoundment facilities to a post-mining beneficial land use of developed water resources. An evaluation of the effect residual materials and lake dynamics would have on in-stream water quality was performed. Eagle Park Reservoir stands as a model for future reclamation efforts that involve water delivery to highly sensitive receiving waters. This paper provides a case study on project development, the evolution of water quality assessment, and the regulatory framework that contributed to this project's success.

  6. Influência do assento da cadeira adaptada na execução de uma tarefa de manuseio Influence of the seat surface of an adapted chair on the performance of a manipulation task

    Directory of Open Access Journals (Sweden)

    Lígia Maria Presumido Braccialli

    2008-04-01

    Full Text Available Este estudo teve como objetivo verificar a influência da flexibilidade da superfície de assento da cadeira na velocidade e no tempo despendido por alunos com paralisia cerebral espástica durante a execução de uma tarefa de manuseio de um objeto na posição sentada. Participaram do estudo 11 alunos, de ambos os gêneros, com diagnóstico de paralisia cerebral espástica, que tinham algum controle de tronco e membros superiores. A quantificação da análise cinemática foi realizada em duas situações experimentais: 1 execução de uma tarefa acadêmica de encaixe, com o indivíduo posicionado em um mobiliário adaptado com assento de lona; 2 execução de uma tarefa acadêmica de encaixe, com o participante posicionado em um mobiliário adaptado com assento de madeira. Os dados obtidos foram submetidos à análise estatística descritiva e não-paramétrica por meio do teste de Wilcoxon. Os resultados indicaram que: 1 a velocidade média de execução das tarefas não foi influenciada pelo tipo de assento utilizado 2 o tempo de execução da tarefa foi influenciada pelo tipo de assento utilizado. A utilização do assento de lona aumentou o tempo de realização da tarefa. Conclui-se que o assento de um mobiliário escolar para um aluno com paralisia cerebral espástica não deve ser confeccionado com um material muito flexível. Este tipo de assento fornecerá uma base instável que dificultará o desempenho do aluno durante atividades realizadas com os membros superiores.The objective of this study was to verify the influence of the flexibility of the seat surface of a chair on the speed and time expended by students with spastic cerebral palsy during the performance of a task involving the manipulation an object while in a seated position. Eleven students of both genders participated in the study; all were diagnosed with spastic cerebral palsy, and all had some control of trunk and upper limbs. The quantification of the kinematics

  7. Effects of Simulated Surface Effect Ship Motions on Crew Habitability. Phase II. Volume 3. Visual-Motor Tasks and Subjective Evaluations

    Science.gov (United States)

    1977-05-01

    simulated rmotions ; and detaiJl.s on the daily work/rest schedule, as well as the overall run ,schedule (Ref.20). * Volume 4, "Crew Cognitive Functions...the outset: 1) the very small sampling of well- motivated crewmen made it difficult to generalize the results to a wider population; and 2) the...a:; backups. Selection of primary crewmen was based on satisfactory task learning and motivation demonstrated during the training period, any minor

  8. Screening Assessment of Radionuclide Migration in Groundwater from the “Dneprovskoe” Tailings Impoundment (Dneprodzerzhynsk City) and Evaluation of Remedial Options

    Energy Technology Data Exchange (ETDEWEB)

    Skalskyi, O.; Bugai, D. [Institute of Geological Sciences, National Academy of Sciences of Ukraine (Ukraine); Ryazantsev, V. [State Nuclear Regularity Committee of Ukraine, Kiev (Ukraine)

    2014-05-15

    The paper presents results of mathematical modeling of the hydrogeological conditions at the “Dneprovskoe” (“D”) tailings impoundment –object of the former industrial association of “Pridneprovsky Chemical Plant”, which contains uranium ore processing wastes. This radioactively polluted site is located in a densely populated region (at the outskirts of Dneprodzerginsk City) near the major watercourse of the Ukraine — Dnieper River.The mathematical modeling utilized Visual Modflow (for groundwater flow) and Ecolego (Facilia AB, Sweden) radioecology modeling software (for radionuclide transport).Modeling results indicate the possibility of essential radioactive contamination in future of the phreatic aquifer in alluvial deposits between the “D” tailings and the Dnieper River (mainly due to migration of uranium). Therefore long-term management strategies should preclude water usage from the aquifer in the zone of the in-fluence of the “D” tailings. Filtration discharge of uranium to the Dnepr River does not represent a significant risk due to large dilution by surface waters. The important modeling conclusion is that besides the uranium ore processing wastes inside the tailings, the major source of radionuclide migration to groundwater is represented by contaminated geological deposits below the tailings. This last source was formed due to leakage of wastewaters during the operational period of the “D” tailings (1954–1968). Therefore an exemption and re-disposal of wastes from the “D” tailings to a more safe storage location (proposed by some remedial plans) will not provide significant benefit from the viewpoint of minimizing of radionuclide transport to the groundwater and Dnieper River (especially in short-and medium-term perspective). The rational remedial strategy for the “D” tailings is conservation of tailing wastes in-situ by means of specially designed “zero flux” soil screen, which would minimize infiltration of

  9. A long-term comparison of carbon sequestration rates in impounded and naturally tidal freshwater marshes along the lower Waccamaw River, South Carolina

    Science.gov (United States)

    Drexler, Judith Z.; Krauss, Ken W.; Sasser, M. Craig; Fuller, Christopher C.; Swarzenski, Christopher M.; Powell, Amber; Swanson, Kathleen M.; Orlando, James L.

    2013-01-01

    Carbon storage was compared between impounded and naturally tidal freshwater marshes along the Lower Waccamaw River in South Carolina, USA. Soil cores were collected in (1) naturally tidal, (2) moist soil (impounded, seasonally drained since ~1970), and (3) deeply flooded “treatments” (impounded, flooded to ~90 cm since ~2002). Cores were analyzed for % organic carbon, % total carbon, bulk density, and 210Pb and 137Cs for dating purposes. Carbon sequestration rates ranged from 25 to 200 g C m−2 yr−1 (moist soil), 80–435 g C m−2 yr−1 (naturally tidal), and 100–250 g C m−2 yr−1 (deeply flooded). The moist soil and naturally tidal treatments were compared over a period of 40 years. The naturally tidal treatment had significantly higher carbon storage (mean = 219 g C m−2 yr−1 vs. mean = 91 g C m−2 yr−1) and four times the vertical accretion rate (mean = 0.84 cm yr−1 vs. mean = 0.21 cm yr−1) of the moist soil treatment. The results strongly suggest that the long drainage period in moist soil management limits carbon storage over time. Managers across the National Wildlife Refuge system have an opportunity to increase carbon storage by minimizing drainage in impoundments as much as practicable.

  10. Water-quality study of Tulpehocken Creek, Berks County, Pennsylvania, prior to impoundment of Blue Marsh Lake

    Science.gov (United States)

    Barker, James L.

    1977-01-01

    Blue Marsh Lake is planned as a multipurpose impoundment to be constructed on Tulpehocken Creek near Bernville, Berks County, Pennsylvania. Prior to construction, samples of water, bed material, and soil were collected throughout the impoundment site to determine concentrations of nutrients, insecticides, trace metals, suspended sediment, and bacteria. Analyses of water suggest the Tulpehocken Creek basin to be a highly fertile environment. Nitrogen and phosphorus concentrations near the proposed dam site had median values of 4.5 and 0.13 mg/L, respectively. Suspended sediment discharges average between 100 and 200 tons (90.7 to 181.4 metric tons) per day during normal flows but may exceed 10,000 tons (9,070 metric tons) per day during storm runoff. Highest yields were measured during winter and early spring. Concentrations range from 3 mg/L to more than 500 mg/L. Bed material samples contain trace quantities of aldrin, DDT, DDD, DDE, dieldrin, and chlordane. Polychlorinated biphyenyls (PCB's) ranged from 10 to 100 μg/kg. Soils at the impoundment site are of average fertility. However, the silt loam texture is ideal for attachment and growth of aquatic plants. Bacteria populations indicative of recent fecal contamination are prevalent in the major inflows to the proposed lake. Fecal Coliform exceeded the standards recommended by the Federal Water Pollution Administration Committee on Water Quality Criteria for public water supply in 29 percent of the monthly samples, and exceeded the recommended public bathing waters standard in 83 percent of the samples collected from June to September. Arsenic from an industrial waste was found in the water, suspended sediment, and bed material of Tulpehocken Creek in concentrations of 0 to 30 μg/l, 2 to 879 μg/l, and 1 to 79 μg/g, respectively. It represents a potential environmental hazard; however, the measured concentrations are less than that known to be harmful to man, fish, or wildlife, according to published water

  11. ITER safety task NID-5a: on the effect of tritium sorption on building surfaces as a passive mechanism for reducing airborne concentrations

    International Nuclear Information System (INIS)

    Natalizio, A.

    1994-09-01

    As part of the source term analysis for ITER, it is important to investigate the potential for building surface interaction with tritium as a potential attenuation mechanism, which in the absence of engineered systems may be effective in reducing tritium environmental releases. (author). 2 refs., 8 tabs., 3 figs

  12. Uptake of uranium, thorium and radium isotopes by plants growing in dam impoundment Tasotkel and the Lower Shu region (Kazakhstan)

    Energy Technology Data Exchange (ETDEWEB)

    Matveyeva, Ilona; Burkitbayev, Mukhambetkali [al-Farabi Kazakh National University, Almaty (Kazakhstan). Faculty of Chemistry and Chemical Technology; Jacimovic, Radojko [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Environmental Sciences; Planinsek, Petra; Smodis, Borut [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Environmental Sciences; Jozef Stefan International Postgraduate School, Ljubljana (Slovenia)

    2016-04-01

    The activity concentrations of isotopes of uranium, thorium and radium-226 in dominant species of plants (Xantium strumarium, Phragmites communis, Artemisia nitrosa and Artemisia serotina) growing on the territories contaminated by uranium industry of Kazakhstan (close to dam impoundment Tasotkel and the Lower Shu region) are presented. The obtained data showed the significant variations of activity concentrations of isotopes of uranium, thorium and radium-226 in above ground parts. The concentrations of most of the investigated radionuclides in the root system are higher than in the aboveground parts; it can be explained by root barrier. It was found that the highest root barrier has Xantium strumarium, especially for uranium isotopes. The concentration ratios of radionuclides were calculated, and as the result it was found that the highest accumulation ability in the investigated region has Artemisia serotina.

  13. Uptake of uranium, thorium and radium isotopes by plants growing in dam impoundment Tasotkel and the Lower Shu region (Kazakhstan)

    International Nuclear Information System (INIS)

    Matveyeva, Ilona; Burkitbayev, Mukhambetkali

    2016-01-01

    The activity concentrations of isotopes of uranium, thorium and radium-226 in dominant species of plants (Xantium strumarium, Phragmites communis, Artemisia nitrosa and Artemisia serotina) growing on the territories contaminated by uranium industry of Kazakhstan (close to dam impoundment Tasotkel and the Lower Shu region) are presented. The obtained data showed the significant variations of activity concentrations of isotopes of uranium, thorium and radium-226 in above ground parts. The concentrations of most of the investigated radionuclides in the root system are higher than in the aboveground parts; it can be explained by root barrier. It was found that the highest root barrier has Xantium strumarium, especially for uranium isotopes. The concentration ratios of radionuclides were calculated, and as the result it was found that the highest accumulation ability in the investigated region has Artemisia serotina.

  14. Proceedings of the 15. annual British Columbia MEND ML/ARD workshop : the management of tailings and tailings impoundments

    International Nuclear Information System (INIS)

    2009-02-01

    This Mine Environment Neutral Drainage (MEND) workshop was held to promote the exchange of information and ideas on environmental protection and reclamation associated with mining. The workshop covered a broad spectrum of reclamation issues and the key environmental challenges facing the mining industry, such as acid mine drainage (AMD) control, and metal leaching and acid rock drainage (ML/ARD). The theme for the 2008 workshop was the management of tailings and tailings impoundments. Topics of discussion included hydrogeology and geochemistry; tailings disposal; mitigation; closure plans; and postclosure performance. The emphasis was on full-scale case studies, practical constraints and sustaining successful disposal strategies and remediation. The session on tailings management reviewed overarching policies and practices; methods of subaerial tailings disposal and case studies of tailings management; and detailed investigations of geochemical properties and processes. The conference featured 22 presentations, of which 4 have been catalogued separately for inclusion in this database. refs., tabs., figs

  15. Reservoir Operation Rules for Controlling Algal Blooms in a Tributary to the Impoundment of Three Gorges Dam

    Directory of Open Access Journals (Sweden)

    Jijian Lian

    2014-10-01

    Full Text Available Since the first impoundment of Three Gorges Dam in 2003, algal blooms occur frequently in the near-dam tributaries. It is widely recognized that the impoundment-induced change in hydrodynamic condition with the lower current velocity will make the eutrophication problem even more severe when an excessive amount of nutrients is already loaded into a reservoir and/or its tributaries. Operation tests carried out by Three Gorges Corporation in 2010 point to some feasible reservoir operation schemes that may have positive impacts on reducing the algal bloom level. In our study, an attempt is made to obtain, through a numerical hydrodynamic and water quality modeling and analysis, the reservoir operation rules that would reduce the level of algal blooms in the Xiangxi River (XXR, a near-dam tributary. Water movements and algal blooms in XXR are simulated and analyzed under different scenarios of one-day water discharge fluctuation or two-week water level variation. The model results demonstrate that the reservoir operations can further increase the water exchange between the mainstream of the Three Gorges Reservoir (TGR and the XXR tributary and thus move a larger amount of algae into the deep water where it will die. Analysis of the model results indicate that the water discharge fluctuation constituted of a lower valley-load flow and a larger flow difference for the short-term operation (within a day, the rise in water level for the medium-term operation (e.g., over weeks, and the combination of the above two for the long-term operation (e.g., over months can be the feasible reservoir operation rules in the non-flood season for TGR.

  16. Impoundment effects in the population of Auchenipterus osteomystax (Siluriformes: Auchenipteridae: a Neotropical reservoir case

    Directory of Open Access Journals (Sweden)

    Elcio Barili

    2012-06-01

    Full Text Available New impoundments provide opportunities to check whether species that present enough feeding flexibility in natural conditions may take advantage of this situation and, without reproductive restriction, can occupy the most conspicuous habitat in a large reservoir (open areas and present higher success in the colonization of the new environment. We examined variations in the abundance and feeding of A. osteomystax in two environments, one natural (Sinha Mariana floodplain lake and one dammed (Manso Reservoir, during two periods: the first year after the filling phase and three years later. Our goal was to evaluate the occupation of the new hábitat (Manso Reservoir, by this species, as well as to test the hypothesis that in the reservoir, unlike the natural environment, there are remarkable changes in diet between the periods. Fish were sampled monthly in the floodplain lake and in the reservoir during two annual periods using gillnets. To evaluate the differences in abundance of A. osteomystax we employed the Kruskal -Wallis test, and the diet analysis was carried out using frequency of occurrence and volumetric methods. Temporal differences in the diet were tested by Kruskal-Wallis test using the scores from a detrended correspondence analysis. A. osteomystax was significantly more abundant in the floodplain lake, where the captures were higher than in the reservoir in almost all months analyzed, and significant variations in abundance between the two periods were not recorded in either the reservoir or the floodplain lake. The diet variation between the two periods, which had a time lag of three years between them, was much less pronounced in the natural environment, where the resource availability is essentially regulated by seasonality. Thus, our hypothesis was accepted; that is, the interannual variations in the diet of A. osteomystax are more relevant in an artificial environment than in a natural one. Rev. Biol. Trop. 60 (2: 699-708. Epub

  17. MRS [monitored retrievable storage] systems study Task G report: The role and functions of surface storage of radioactive material in the federal waste management system

    International Nuclear Information System (INIS)

    Wood, T.W.; Short, S.M.; Woodruff, M.G.; Altenhofen, M.K.; MacKay, C.A.

    1989-04-01

    This is one of nine studies undertaken by contractors to the US Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), to provide a technical basis for re-evaluating the role of a monitored retrievable storage (MRS) facility. The study investigates the functions that could be performed by surface storage of radioactive material within the federal radioactive waste management system, including enabling acceptance of spent fuel from utility owners, scheduling of waste-preparation processes within the system, enhancement of system operating reliability, and conditioning the thermal (decay heat) characteristics of spent fuel emplaced in a repository. The analysis focuses particularly on the effects of storage capacity and DOE acceptance schedule on power reactors. Figures of merit developed include the storage capacity [in metric tons of uranium (MTU)] required to be added beyond currently estimated maximum spent fuel storage capacities and its associated cost, and the number of years that spent fuel pools would remain open after last discharge (in pool-years) and the cost of this period of operation. 27 refs., 36 figs., 18 tabs

  18. Change characteristics of DSi and nutrition structure at the Yangtze River Estuary after Three Gorges Project impounding and their ecological effect

    Directory of Open Access Journals (Sweden)

    Li Lei

    2017-06-01

    Full Text Available The variation law of dissolved silica (DSi, dissolved inorganic nitrogen (DIN, dissolved inorganic phosphorus (DIP and nutrition structure after the Three Gorges Project (TGP impounding as well as their ecological effect were analyzed according to monitoring survey of the Yangtze River Estuary in spring (May and summer (August from 2004-2009. The results showed that after impounding, DSi and DIN concentration decreased and increased, respectively. During the study period, DSi decreased by about 63%, while DIN almost tripled. DIP concentration fluctuated slightly. With respect to nutrition structure, N:P increased, whereas Si:P and Si:N declined. According to chemometry standard of nutrient limits, nutrition structure tended to be imbalanced and the limiting factor of phytoplankton growth (P was studied. Changes of nutrition structure have largely decreased diatom and caused different composition of dominant phytoplankton species. This may change ecosystem structure of the Yangtze River Estuary.

  19. Synchronous response of sedimentary organic carbon accumulation on the inner shelf of the East China Sea to the water impoundment of Three Gorges and Gezhouba Dams

    Science.gov (United States)

    Lin, Jia; Zhu, Qing; Hong, Yuehui; Yuan, Lirong; Liu, Jinzhong; Xu, Xiaoming; Wang, Jianghai

    2018-01-01

    Coastal seas, located between continents and the open ocean, are an important active carbon pool. The sedimentary total organic carbon (TOC) in these areas is a mixture of terrestrial and marine sources, and can be a powerful proxy for tracing natural processes and human activities. In this study, one fine-grained sediment core (DH5-1) from the inner shelf of the East China Sea was systematically analyzed for TOC and black carbon (BC) contents and TOC stable carbon isotope ratios (δ13C). By combining these data with 210Pb dating, an improved carbon correction model and a two end-member mixing model, we reconstructed century-scale high-resolution sequences of corrected TOC, terrestrial TOC and marine TOC contents and identified two carbon depletion events in the DH5-1 record. The two events, shown as two minima in the TOC profiles, correspond temporally to 1985-1987 AD and 2003-2006 AD, which exactly matches the water impoundment of the Gezhouba Dam and Three Gorges Dam, respectively. In addition, the variations in TOC contents and δ13C values before, during or after the minima demonstrate a relationship between the depletion events and water impoundment of the dams on the Changjiang River. The TOC reductions may represent synchronous responses of sedimentary TOC and resultant ecological effects on the inner shelf of the East China Sea to the water impoundment of the dams. These new TOC records reflect the interaction between natural and anthropogenic processes and, accordingly, provide a deep insight and important references for assessing marine ecological effects resulting from water impoundment of largescale dams.

  20. Mercury concentrations of fish in Southern Indian Lake and Issett Lake, Manitoba 1975-88: The effect of lake impoundment and Churchill River diversion

    International Nuclear Information System (INIS)

    Strange, N.E.; Bodaly, R.A.; Fudge, R.J.P.

    1991-01-01

    Southern Indian and Issett Lakes in northern Manitoba were flooded in 1976 as part of Manitoba Hydro's Churchill River diversion project. Fish were collected from 1975 to 1988 from five regional sites on the lakes to examine the effects of impoundment and river diversion on muscle mercury concentrations. Raw data for individual fish caught in 1987 and 1988 are presented, along with means and analyses calculated over the entire 1975-1988 study period. Mercury concentrations in whitefish, pike, and walleye increased significantly after impoundment. Whitefish mercury levels peaked in 1978 and have since declined to near pre-flooding levels. Northern pike and walleye mercury levels were much higher than for whitefish. Pike mercury concentrations showed no indication of declining after 12 years of impoundment, but walleye mercury levels at 2 of the 5 Southern Indian Lake sites declined from maximum recorded levels. Significant variability in fish mercury concentrations was noted both from year to year and among the sites. It is suggested that site-to-site variations are due to varying conditions in the reservoir which stimulate mercury methylation. Since there appears to be an ongoing long-term source of mercury and organic material from the eroding shorelines, pike and walleye mercury concentrations are expected to remain high for many years. 25 refs., 7 figs., 20 tabs

  1. Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

    Science.gov (United States)

    Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

    2009-01-01

    Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

  2. 30 CFR 780.25 - Reclamation plan: Siltation structures, impoundments, and refuse piles.

    Science.gov (United States)

    2010-07-01

    ... is capable of being done after consideration of cost, logistics, and available technology. The fact... COAL EXPLORATION SYSTEMS UNDER REGULATORY PROGRAMS SURFACE MINING PERMIT APPLICATIONS-MINIMUM..., and refuse piles. (a) General. Each application must include a general plan and a detailed design plan...

  3. Overland erosion of uranium-mill-tailings impoundments: physical processes and computational methods

    International Nuclear Information System (INIS)

    Walters, M.H.

    1983-03-01

    The surface runoff and erosional processes of watersheds caused by rainfall-runoff are reviewed. Soil properties, topography, and rainstorm distribution are discussed with respect to their effects on soil erosion. The effects of climate and vegetation are briefly presented. Regression models and physical process simulation models are reviewed

  4. Predictive geochemical modeling of contaminant concentrations in laboratory columns and in plumes migrating from uranium mill tailings waste impoundments

    International Nuclear Information System (INIS)

    Peterson, S.R.; Martin, W.J.; Serne, R.J.

    1986-04-01

    A computer-based conceptual chemical model was applied to predict contaminant concentrations in plumes migrating from a uranium mill tailings waste impoundment. The solids chosen for inclusion in the conceptual model were selected based on reviews of the literature, on ion speciation/solubility calculations performed on the column effluent solutions and on mineralogical characterization of the contacted and uncontacted sediments. The mechanism of adsorption included in the conceptual chemical model was chosen based on results from semiselective extraction experiments and from mineralogical characterization procedures performed on the sediments. This conceptual chemical model was further developed and partially validated in laboratory experiments where assorted acidic uranium mill tailings solutions percolated through various sediments. This document contains the results of a partial field and laboratory validation (i.e., test of coherence) of this chemical model. Macro constituents (e.g., Ca, SO 4 , Al, Fe, and Mn) of the tailings solution were predicted closely by considering their concentrations to be controlled by the precipitation/dissolution of solid phases. Trace elements, however, were generally predicted to be undersaturated with respect to plausible solid phase controls. The concentration of several of the trace elements were closely predicted by considering their concentrations to be controlled by adsorption onto the amorphous iron oxyhydroxides that precipitated

  5. Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention.

    Science.gov (United States)

    Kroeger, Kevin D; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

    2017-09-20

    Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as "Blue Carbon"), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH 4 ) and CO 2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH 4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

  6. Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention

    Science.gov (United States)

    Kroeger, Kevin D.; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

    2017-01-01

    Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as “Blue Carbon”), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH4) and CO2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

  7. Influence of vegetation and sewage sludge on sealing layer of fly ashes in post-treatment of mine tailings impoundments; Inverkan av vegetation och roetslam paa taetskikt av flygaska vid efterbehandling av sandmagasin

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria; Neuschuetz, Clara (Inst. of Bothany, Stockholm Univ., Stockholm (Sweden)); Isaksson, Karl-Erik (Boliden Mineral AB, Stockholm (Sweden))

    2009-03-15

    Mining industry produces 25 Mton mine tailings yearly that are deposited in impoundments in the nature. When this sand, containing sulphur rich minerals, reacts with oxygen and water it starts to weather and acidic metal rich water is formed. To prevent this, the sand can be covered with a sealing layer and a protective cover layer with vegetation. As sealing and cover materials fly ashes and sewage sludge can be used. The aim of this investigation was to find out: 1) how sealing layer of fly ashes with and without sewage sludge, and a cover with sewage sludge can be placed practically on mine tailings in a cold climate. 2) how such a cover should be constructed to minimize the risk of root penetration and leakage of nutrients and metals 3) which vegetation that is most suitable This was investigated in field- and greenhouse tests with a sealing layer of fly ash and/or sewage sludge with a cover layer of sewage sludge in which different plant species were established. The practical application was performed in 0.3-1 ha plots at a mine tailings impoundments at Boliden. The ability of plant roots to penetrate a sealing layer was investigated, as well as the effect of simulated root exudates on the penetration resistance in hardened ash. Leakage of nutrients and metals from cover layer of sewage sludge, in some cases with sealing layers beneath, was investigated in field and greenhouse lysimeters. Various plant species were compared on their ability to affect metal and nutrient leakage as well as root penetration and shattering of the hardened ashes. The project was a cooperation between Stockholm University and Boliden Mineral AB, and the field tests were performed at the impoundment Gillervattnet in Boliden and in Garpenberg. Cooperating were also Iggesund Paperboard, Skellefteaa Kraft, Stora Enso Fors, Umeaa Energi and Vattenfall, all producers of ashes that were used, as well as Stockholm Vatten AB, which produced the sewage sludge. The most important conclusions

  8. Cognitive task analysis

    NARCIS (Netherlands)

    Schraagen, J.M.C.

    2000-01-01

    Cognitive task analysis is defined as the extension of traditional task analysis techniques to yield information about the knowledge, thought processes and goal structures that underlie observable task performance. Cognitive task analyses are conducted for a wide variety of purposes, including the

  9. Sulfide oxidation and acid mine drainage formation within two active tailings impoundments in the Golden Quadrangle of the Apuseni Mountains, Romania.

    Science.gov (United States)

    Sima, Mihaela; Dold, Bernhard; Frei, Linda; Senila, Marin; Balteanu, Dan; Zobrist, Jurg

    2011-05-30

    Sulfidic mine tailings have to be classified as one of the major source of hazardous materials leading to water contamination. This study highlights the processes leading to sulfide oxidation and acid mine drainage (AMD) formation in the active stage of two tailings impoundments located in the southern part of the Apuseni Mountains, in Romania, a well-known region for its long-term gold-silver and metal mining activity. Sampling was undertaken when both impoundments were still in operation in order to assess their actual stage of oxidation and long-term behavior in terms of the potential for acid mine drainage generation. Both tailings have high potential for AMD formation (2.5 and 3.7 wt.% of pyrite equivalent, respectively) with lesser amount of carbonates (5.6 and 3.6 wt.% of calcite equivalent) as neutralization potential (ABA=-55.6 and -85.1 tCaCO(3)/1000 t ) and showed clear signs of sulfide oxidation yet during operation. Sequential extraction results indicate a stronger enrichment and mobility of elements in the oxidized tailings: Fe as Fe(III) oxy-hydroxides and oxides (transformation from sulfide minerals, leaching in oxidation zone), Ca mainly in water soluble and exchangeable form where gypsum and calcite are dissolved and higher mobility of Cu for Ribita and Pb for Mialu. Two processes leading to the formation of mine drainage at this stage could be highlighted (1) a neutral Fe(II) plume forming in the impoundment with ferrihydrite precipitation at its outcrop and (2) acid mine drainage seeping in the unsaturated zone of the active dam, leading to the formation of schwertmannite at its outcrop. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Task demand, task management, and teamwork

    Energy Technology Data Exchange (ETDEWEB)

    Braarud, Per Oeivind; Brendryen, Haavar

    2001-03-15

    The current approach to mental workload assessment in process control was evaluated in 3 previous HAMMLAB studies, by analysing the relationship between workload related measures and performance. The results showed that subjective task complexity rating was related to team's control room performance, that mental effort (NASA-TLX) was weakly related to performance, and that overall activity level was unrelated to performance. The results support the argument that general cognitive measures, i.e., mental workload, are weakly related to performance in the process control domain. This implies that other workload concepts than general mental workload are needed for valid assessment of human reliability and for valid assessment of control room configurations. An assessment of task load in process control suggested that how effort is used to handle task demand is more important then the level of effort invested to solve the task. The report suggests two main workload related concepts with a potential as performance predictors in process control: task requirements, and the work style describing how effort is invested to solve the task. The task requirements are seen as composed of individual task demand and team demand. In a similar way work style are seen as composed of individual task management and teamwork style. A framework for the development of the concepts is suggested based on a literature review and experiences from HAMMLAB research. It is suggested that operational definitions of workload concepts should be based on observable control room behaviour, to assure a potential for developing performance-shaping factors. Finally an explorative analysis of teamwork measures and performance in one study indicated that teamwork concepts are related to performance. This lends support to the suggested development of team demand and teamwork style as elements of a framework for the analysis of workload in process control. (Author)

  11. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik

    1998-01-01

    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  12. Task assignment and coaching

    OpenAIRE

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching from a manager, the junior employee only has information about his past performance. Based on his past performance, a talented junior who has performed a difficult task sometimes decides to leave the...

  13. Functional Task Test (FTT)

    Science.gov (United States)

    Bloomberg, Jacob J.; Mulavara, Ajitkumar; Peters, Brian T.; Rescheke, Millard F.; Wood, Scott; Lawrence, Emily; Koffman, Igor; Ploutz-Snyder, Lori; Spiering, Barry A.; Feeback, Daniel L.; hide

    2009-01-01

    This slide presentation reviews the Functional Task Test (FTT), an interdisciplinary testing regimen that has been developed to evaluate astronaut postflight functional performance and related physiological changes. The objectives of the project are: (1) to develop a set of functional tasks that represent critical mission tasks for the Constellation Program, (2) determine the ability to perform these tasks after space flight, (3) Identify the key physiological factors that contribute to functional decrements and (4) Use this information to develop targeted countermeasures.

  14. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching

  15. The multi-task barge: a floating deep-sea production, storage and unloading unit, with surface production heads and drilling installations; La barge multifonctions: une unite flottante de production, de stockage et dechargement en eau profonde, avec tetes de production en surface et installations de forage

    Energy Technology Data Exchange (ETDEWEB)

    Valenchon, C; Rossig, J H [Bouygues Offshore (France); Pouget, G [Sedco-Forex (France); Biolley, F [Institut Francais du Petrole, 92 - Rueil-Malmaison (France)

    1998-05-01

    The multi-task barge is devoted to the exploitation of deep-sea fields in rather good conditions. It has been designed to bring together within a single installation, a production, storage and unloading unit and the necessary means for the drilling, the connecting and the work-over of wells. Thus submarine well-heads and well-head platforms are no longer needed. When the field configuration or the use of oriented drillings allows to group several wells together, the multi-task platform allows to use more economical surface production heads installed on steel rigid risers. This concept requires less investments thanks to less expensive drilling operations and restricted submarine installations, and to easier well operations and lower exploitation costs. Crude oil storage is ensured to up to about 2 millions of barrels. This paper presents the design aspects and the dynamical analysis of risers with the methods used. The tensioning and mooring system is examined and the advantages of the cylindrical float system is underlined and compared to the classical hydro-pneumatic systems. (J.S.) 11 refs.

  16. Transport Task Force Leadership, Task 4

    International Nuclear Information System (INIS)

    Callen, J.D.

    1991-07-01

    The Transport Task Force (TTF) was initiated as a broad-based US magnetic fusion community activity during the fall of 1988 to focus attention on and encourage development of an increased understanding of anomalous transport in tokamaks. The overall TTF goal is to make progress on Characterizing, Understanding and Identifying how to Reduce plasma transport in tokamaks -- to CUIR transport

  17. "Photographing money" task pricing

    Science.gov (United States)

    Jia, Zhongxiang

    2018-05-01

    "Photographing money" [1]is a self-service model under the mobile Internet. The task pricing is reasonable, related to the success of the commodity inspection. First of all, we analyzed the position of the mission and the membership, and introduced the factor of membership density, considering the influence of the number of members around the mission on the pricing. Multivariate regression of task location and membership density using MATLAB to establish the mathematical model of task pricing. At the same time, we can see from the life experience that membership reputation and the intensity of the task will also affect the pricing, and the data of the task success point is more reliable. Therefore, the successful point of the task is selected, and its reputation, task density, membership density and Multiple regression of task positions, according to which a nhew task pricing program. Finally, an objective evaluation is given of the advantages and disadvantages of the established model and solution method, and the improved method is pointed out.

  18. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina

    2012-01-01

    identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings....... The findings show that: (i) Board processes have a larger potential than demographic variables to explain board task performance; (ii) board task performance differs significantly between boards operating in different contexts; and (iii) national context moderates the relationships between board processes...... and board task performance....

  19. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    , is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...

  20. Task leaders reports

    International Nuclear Information System (INIS)

    Loriaux, E.F.; Jehee, J.N.T.

    1995-01-01

    Report on CRP-OSS Task 4.1.1. ''Survey of existing documentation relevant to this programme's goals'' and report on CRP-OSS Task 4.1.2. ''Survey of existing Operator Support Systems and the experience with them'' are presented. 2 tabs

  1. Prevalence of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA), Durban and Coast, South Africa.

    Science.gov (United States)

    Mukaratirwa, S; Singh, V P

    2010-06-01

    Coprological examination was used to determine the prevalence and intensity of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA), Durban and Coast, South Africa. Helminth and protozoan parasites were found in faeces of 240 dogs with an overall prevalence of 82.5% (helminth parasites 93.1% and protozoan parasites 6.9%). The following parasites and their prevalences were detected; Ancylostoma sp. (53.8%), Trichuris vulpis (7.9%), Spirocerca lupi (5.4%), Toxocara canis (7.9%), Toxascaris leonina (0.4%) Giardia intestinalis (5.6%) and Isospora sp. (1.3%). Dogs harbouring a single parasite species were more common (41.7%) than those harbouring 2 (15%) or multiple (2.1%) species. Ancylostoma sp., Toxocara canis and Giardia intestinalis have zoonotic potential and were detected in 66.7% of the samples.

  2. Prevalence of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA, Durban and Coast, South Africa : short communication

    Directory of Open Access Journals (Sweden)

    S. Mukaratirwa

    2010-05-01

    Full Text Available Coprological examination was used to determine the prevalence and intensity of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA, Durban and Coast, South Africa. Helminth and protozoan parasites were found in faeces of 240 dogs with an overall prevalence of 82.5% (helminth parasites 93.1% and protozoan parasites 6.9 %. The following parasites and their prevalences were detected; Ancylostoma sp. (53.8 %, Trichuris vulpis (7.9 %, Spirocerca lupi (5.4 %, Toxocara canis (7.9 %, Toxascaris leonina (0.4 % Giardia intestinalis (5.6 % and Isospora sp. (1.3 %. Dogs harbouring a single parasite species were more common (41.7 % than those harbouring 2 (15 % or multiple (2.1 % species. Ancylostoma sp., Toxocara canis and Giardia intestinalis have zoonotic potential and were detected in 66.7 % of the samples.

  3. Effects of dams in river networks on fish assemblages in non-impoundment sections of rivers in Michigan and Wisconsin, USA

    Science.gov (United States)

    Stewart, Jana S.; Lizhu Wang,; Infante, Dana M.; Lyons, John D.; Arthur Cooper,

    2011-01-01

    Regional assessment of cumulative impacts of dams on riverine fish assemblages provides resource managers essential information for dam operation, potential dam removal, river health assessment and overall ecosystem management. Such an assessment is challenging because characteristics of fish assemblages are not only affected by dams, but also influenced by natural variation and human-induced modification (in addition to dams) in thermal and flow regimes, physicochemical habitats and biological assemblages. This study evaluated the impacts of dams on river fish assemblages in the non-impoundment sections of rivers in the states of Michigan and Wisconsin using multiple fish assemblage indicators and multiple approaches to distinguish the influences of dams from those of other natural and human-induced factors. We found that environmental factors that influence fish assemblages in addition to dams should be incorporated when evaluating regional effects of dams on fish assemblages. Without considering such co-influential factors, the evaluation is inadequate and potentially misleading. The role of dams alone in determining fish assemblages at a regional spatial scale is relatively small (explained less than 20% of variance) compared with the other environmental factors, such as river size, flow and thermal regimes and land uses jointly. However, our results do demonstrate that downstream and upstream dams can substantially modify fish assemblages in the non-impoundment sections of rivers. After excluding river size and land-use influences, our results clearly demonstrate that dams have significant impacts on fish biotic-integrity and habitat-and-social-preference indicators. The influences of the upstream dams, downstream dams, distance to dams, and dam density differ among the fish indicators, which have different implications for maintaining river biotic integrity, protecting biodiversity and managing fisheries.

  4. Holocene Record of Major and Trace Components in the Sediments of an Urban Impoundment on the Mississippi River: Lake Pepin, Minnesota and Wisconsin

    Science.gov (United States)

    Dean, Walter E.

    2009-01-01

    Lake Pepin is a natural impoundment formed by damming of the Mississippi River about 9,180 radiocarbon years ago (19,600 calendar years) by an alluvial fan deposited by the Chippewa River, a tributary of the Mississippi in Wisconsin. Unique among 26 Mississippi River impoundments, Lake Pepin has stratigraphically preserved Holocene materials, including pollutants, that have been transported down the Mississippi. This natural Holocene record can then be compared to changes that have occurred since European settlement (ca. AD 1830), and since enactment of clean air and water legislation. The most immediate response to settlement in the sediments of Lake Pepin was an increase in bulk-sediment accumulation rate. This was accompanied by gradual increases in concentrations of phosphorus (P), and organic carbon (OC), followed by dramatic increases in these elements beginning about 1940. The increase in P was far greater than any of the minor fluctuations in P that occurred throughout the Holocene, but the increase in OC was comparable to an increase in OC that occurred in the mid-Holocene. The concentrations of several metals (for example, cadmium [Cd], and lead [Pb]) also are elevated in recent sediments. Increased Cd concentrations lasted only about two decades during the industrial era between World War II and the enactment of clean water standards in the 1970s. Increased Pb emissions, on the other hand, occurred over more than 100 years, first from burning of coal and smelting of lead ores, and then, beginning in the 1930s, burning of leaded gasoline. Concentrations of Pb in the sediments of Lake Pepin decreased to about two times preindustrial levels within a decade of enactment of unleaded gasoline restrictions.

  5. Changes in the fish community of the Kpong Headpond, lower Volta River, Ghana after 25 years of impoundment

    Directory of Open Access Journals (Sweden)

    Theodore Quarcoopome

    2011-12-01

    Full Text Available The Kpong Headpond was the second created on the Volta River after Akosombo Dam, primarily as a source of hydroelectric power generation and potable water supply, and additionally, it has supported some fish production in Ghana since impoundment. The changes in fish community of the Kpong Headpond were studied to provide baseline information for strategies formulation to support the socio-economic development of the reservoir. The study identified changes in the fish community of the reservoir by comparing occurrence, composition, relative abundance and relative importance estimates of fish species, families and trophic groups, from available previous studies in the reservoir. From the collated information all fishes identified in the reservoir were categorised based on occurrence and importance as disappeared, appeared, permanent, declined or important, to show current status. The results indicated that the fish community has experienced a shift in the composition and relative abundance of important species, families and trophic groups in terms of number and weight, while remaining ecologically balanced. Representatives of the families Osteoglossidae, Centropomidae and Characidae have declined while representatives of the families Claroteidae, Cyprinidae and Cichlidae have increased. The aufwuch-detritus and herbivores declined while semi-pelagic omnivores increased resulting in a shift in dominance to benthic and semi pelagic omnivores. The appearance of five species and the disappearance of 25 others indicated a dynamic restructuring of the fish community in the reservoir, as expected. Enforcement of fishing regulations including the use of appropriate gear and fishing methods, fishery access control, promotion of culture-based fisheries and improvement in fisher education are recommended topics for sustainable fisheries in the reservoir. Rev. Biol. Trop. 59 (4: 1685-1696. Epub 2011 December 01.La laguna Kpong se convirtió en la segunda

  6. Generic cognitive adaptations to task interference in task switching

    NARCIS (Netherlands)

    Poljac, E.; Bekkering, H.

    2009-01-01

    The present study investigated how the activation of previous tasks interferes with the execution of future tasks as a result of temporal manipulations. Color and shape matching tasks were organized in runs of two trials each. The tasks were specified by a cue presented before a task run, cueing

  7. Balancing the Demands of Two Tasks: An Investigation of Cognitive-Motor Dual-Tasking in Relapsing Remitting Multiple Sclerosis.

    Science.gov (United States)

    Butchard-MacDonald, Emma; Paul, Lorna; Evans, Jonathan J

    2018-03-01

    People with relapsing remitting multiple sclerosis (PwRRMS) suffer disproportionate decrements in gait under dual-task conditions, when walking and a cognitive task are combined. There has been much less investigation of the impact of cognitive demands on balance. This study investigated whether: (1) PwRRMS show disproportionate decrements in postural stability under dual-task conditions compared to healthy controls, and (2) dual-task decrements are associated with everyday dual-tasking difficulties. The impact of mood, fatigue, and disease severity on dual-tasking was also examined. A total of 34 PwRRMS and 34 matched controls completed cognitive (digit span) and balance (movement of center of pressure on Biosway on stable and unstable surfaces) tasks under single- and dual-task conditions. Everyday dual-tasking was measured using the Dual-Tasking Questionnaire. Mood was measured by the Hospital Anxiety & Depression Scale. Fatigue was measured via the Modified Fatigue Index Scale. No differences in age, gender, years of education, estimated pre-morbid IQ, or baseline digit span between groups. Compared with controls, PwRRMS showed significantly greater decrement in postural stability under dual-task conditions on an unstable surface (p=.007), but not a stable surface (p=.679). Balance decrement scores were not correlated with everyday dual-tasking difficulties or fatigue. Stable surface balance decrement scores were significantly associated with levels of anxiety (rho=0.527; p=.001) and depression (rho=0.451; p=.007). RRMS causes dual-tasking difficulties, impacting balance under challenging conditions, which may contribute to increased risk of gait difficulties and falls. The relationship between anxiety/depression and dual-task decrement suggests that emotional factors may be contributing to dual-task difficulties. (JINS, 2018, 24, 247-258).

  8. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld

    2014-01-01

    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...

  9. Contaminated sediment research task: SHC Task 3.61.3

    Science.gov (United States)

    A poster presentation for the SHC BOSC review will summarize the research efforts under Sustainable and Healthy Communities Research Program (SHC) in the Contaminated Sediment Task within the Contaminated Sites Project. For the Task, Problem Summary & Decision Context; Task O...

  10. Simulated effects of existing and proposed surface-water impoundments and gas-well pads on streamflow and suspended sediment in the Cypress Creek watershed, Arkansas

    Science.gov (United States)

    Hart, Rheannon M.

    2014-01-01

    Cypress Creek is located in central Arkansas and is the main tributary to Brewer Lake, which serves as the primary water supply for Conway, Arkansas, and the surrounding areas. A model of the Cypress Creek watershed was developed and calibrated in cooperation with Southwestern Energy Company using detailed precipitation, streamflow, and discrete suspended-sediment data collected from 2009 through 2012. These data were used with a Hydrologic Simulation Program—FORTRAN model to address different potential gas-extraction activities within the watershed.

  11. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    Science.gov (United States)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  12. Robot task space analyzer

    International Nuclear Information System (INIS)

    Hamel, W.R.; Osborn, J.

    1997-01-01

    Many nuclear projects such as environmental restoration and waste management challenges involve radiation or other hazards that will necessitate the use of remote operations that protect human workers from dangerous exposures. Remote work is far more costly to execute than what workers could accomplish directly with conventional tools and practices because task operations are slow and tedious due to difficulties of remote manipulation and viewing. Decades of experience within the nuclear remote operations community show that remote tasks may take hundreds of times longer than hands-on work; even with state-of-the-art force- reflecting manipulators and television viewing, remote task performance execution is five to ten times slower than equivalent direct contact work. Thus the requirement to work remotely is a major cost driver in many projects. Modest improvements in the work efficiency of remote systems can have high payoffs by reducing the completion time of projects. Additional benefits will accrue from improved work quality and enhanced safety

  13. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    by shared goals and knowledge as well as mutual respect and frequent, timely, accurate and problem-solving ways of communication with the purpose of dealing with the tasks at hand in an integrated way. We introduce and discuss relational coordination theory through a case-study within public healthcare....... Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  14. Resource use by the facultative lepidophage Roeboides affinis (Günther, 1868: a comparison of size classes, seasons and environment types related to impoundment

    Directory of Open Access Journals (Sweden)

    Miriam P. Albrecht

    Full Text Available We report the consumption of scales and other food resources by the facultative lepidophage Roeboides affinis in the upper Tocantins River where it was impounded by the Serra da Mesa Hydroelectric Dam. We compared the diet among size classes, between dry and wet seasons, and between sites with distinct water flow characteristics (lotic vs. lentic related to the distance from the dam and phase of reservoir development. As transparency and fish abundance increased after impoundment, we expected a higher consumption of scales in lentic sites. Likewise, habitat contraction, higher transparency and decrease in terrestrial resources availability, would promote a higher consumption of scales. Scales were consumed by 92% of individuals and represented 26% of the total volume of resources ingested by R. affinis. Diet composition varied significantly among size classes, with larger individuals consuming more scales and larger items, especially odonatans and ephemeropterans. Scale consumption was not significantly different between dry and wet seasons. Roeboides affinis incorporated some food items into the diet as a response to the impoundment, like other species. Scale consumption was higher in lotic sites, refuting our initial hypothesis, what suggests that the lepidophagous habit is related the rheophilic nature of R. affinis.Caracterizamos o consumo de escamas e outros recursos alimentares por Roeboides affinis, um lepidófago facultativo, no alto rio Tocantins, na região represada pela Usina Hidrelétrica de Serra da Mesa. A dieta foi avaliada em relação a classes de tamanho, estações chuvosa e seca, e entre locais com características distintas de fluxo d'água (lótico vs. lêntico relacionadas com a distância da barragem e fase de desenvolvimento do reservatório. Com o aumento da abundância de peixes e da transparência da água após o represamento, esperamos um maior consumo de escamas nos locais lênticos. Da mesma forma, na época seca

  15. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  16. Tasks of the Shipboard Independent Duty Hospital Corpsman. Task Training Adequacy and Performance Frequency.

    Science.gov (United States)

    1987-11-01

    Frequency List E-1 Appendix F - Submarine Quick Reference Task Frequency List . F-1 0 Appendix G - Mean Performance...j~~~~~~, -,,-p.r.. ... .0 -. %... h. • - III APPENDIX E I SURFACE SHIP QUICK REFERENCE TASK FREQUENCY LIST A Q N E Dl It T T E A E H HI K I L L L1 L...34. - - - ----------------------------------------- ---.--- ---------------------- - - E-4 APPENDIX F " SUBMARINE QUICK REFERENCE TASK FREQUENCY LIST (N 1l0) "% R 0 W 4. A Q N E D R T T

  17. Data Center Tasking.

    Science.gov (United States)

    Temares, M. Lewis; Lutheran, Joseph A.

    Operations tasking for data center management is discussed. The original and revised organizational structures of the data center at the University of Miami are also described. The organizational strategy addresses the functions that should be performed by the data center, anticipates the specialized skills required, and addresses personnel…

  18. Biomedical applications engineering tasks

    Science.gov (United States)

    Laenger, C. J., Sr.

    1976-01-01

    The engineering tasks performed in response to needs articulated by clinicians are described. Initial contacts were made with these clinician-technology requestors by the Southwest Research Institute NASA Biomedical Applications Team. The basic purpose of the program was to effectively transfer aerospace technology into functional hardware to solve real biomedical problems.

  19. India's Unfinished Telecom Tasks

    Indian Academy of Sciences (India)

    India's Telecom Story is now well known · Indian Operators become an enviable force · At the same time · India Amongst the Leaders · Unfinished Tasks as Operators · LightGSM ON: Innovation for Rural Area from Midas · Broadband Access Options for India · Broadband driven by DSL: still too slow · Is Wireless the answer?

  20. Microprocessor multi-task monitor

    International Nuclear Information System (INIS)

    Ludemann, C.A.

    1983-01-01

    This paper describes a multi-task monitor program for microprocessors. Although written for the Intel 8085, it incorporates features that would be beneficial for implementation in other microprocessors used in controlling and monitoring experiments and accelerators. The monitor places permanent programs (tasks) arbitrarily located throughout ROM in a priority ordered queue. The programmer is provided with the flexibility to add new tasks or modified versions of existing tasks, without having to comply with previously defined task boundaries or having to reprogram all of ROM. Scheduling of tasks is triggered by timers, outside stimuli (interrupts), or inter-task communications. Context switching time is of the order of tenths of a milllisecond

  1. Analysis of the behaviour of embankment dams during and after impoundment; Analyse du comportement de barrages en remblai pendant et apres leur mise en eau

    Energy Technology Data Exchange (ETDEWEB)

    Massiera, M. [Moncton Univ., Moncton, NB (Canada). Dept. of Civil Engineering; Szostak-Chrzanowski, A; Bazanowski, M. [New Brunswick Univ., Fredericton, NB (Canada). Canadian Centre for Geodetic Engineering; Withaker, C. [Metropolitan Water District of Southern California MWD, Glendora, CA (United States)

    2009-07-01

    This paper analyzed the behaviour of 2 embankment dams during impoundment. The study compared the values of the observed and calculated displacements of the crest during the initial filling of the reservoirs at the zoned earth West Dam in California and the Tounustouc concrete face rockfill dam (CFRD) in Quebec. The calculations were performed using finite element analysis. Rock and earthfill dams constructed on moraine deposits are known to deform under the influence of water load as the reservoir is filled. Therefore, this study also analyzed the long term deformations of the West Dam during 4 subsequent years of operation of the reservoir. Modelling rock and earthfill dams takes into account the nonlinear behaviour of the construction materials; interaction between the structure and the underlying soil and rock strata; influence of water load on the structure and on the foundation bedrock; and the effects of water saturation. This paper showed that geotechnical and geodetic monitoring may provide a warning system in case of abnormal behaviour of the embankment dam. In tectonically active zones, monitoring surveys may also provide information on the effects of seismic disturbances. 18 refs., 11 figs.

  2. Task Force report

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The International Task Force on Prevention of Nuclear Terrorism was formed in 1985 under the auspices of the Nuclear Control Institute. This report is a consensus report of the 26 task force members - all members not necessarily agreeing on every point and all wordings, but in each case a substantial majority did agree. First, the report defines the threat, then establishes the priorities. Short-term recommendations are presented on: (1) protecting nuclear weapons; (2) protecting nuclear materials; (3) protecting nuclear facilities; (4) intelligence programs; (5) civil liberties concerns; (6) controlling nuclear transfers; (7) US - Soviet cooperation; (8) arms control initiatives; (9) convention of physical protection of nuclear material; (10) role of emergency management programs; and (11) role of the media. Brief long-term recommendations are included on (1) international measures, and (2) emerging nuclear technologies. An Appendix, Production of Nuclear Materials Usable in Weapons is presented for further consideration (without recommendations)

  3. Rostering and Task Scheduling

    DEFF Research Database (Denmark)

    Dohn, Anders Høeg

    . The rostering process is non-trivial and especially when service is required around the clock, rostering may involve considerable effort from a designated planner. Therefore, in order to minimize costs and overstaffing, to maximize the utilization of available staff, and to ensure a high level of satisfaction...... as possible to the available staff, while respecting various requirements and rules and while including possible transportation time between tasks. This thesis presents a number of industrial applications in rostering and task scheduling. The applications exist within various contexts in health care....... Mathematical and logic-based models are presented for the problems considered. Novel components are added to existing models and the modeling decisions are justified. In one case, the model is solved by a simple, but efficient greedy construction heuristic. In the remaining cases, column generation is applied...

  4. The task force process

    International Nuclear Information System (INIS)

    Applegate, J.S.

    1995-01-01

    This paper focuses on the unique aspects of the Fernald Citizens Task Force process that have contributed to a largely successful public participation effort at Fernald. The Fernald Citizens Task Force passed quickly by many procedural issues. Instead, the Task Force concentrated on (a) educating itself about the site, its problems, and possible solutions, and (b) choosing a directed way to approach its mandate: To make recommendations on several open-quotes big pictureclose quotes issues, including future use of the site, cleanup levels, waste disposition, and cleanup priorities. This paper presents the approach used at Fernald for establishing and running a focused site-specific advisory board, the key issues that have been faced, and how these issues were resolved. The success of Fernald in establishing a strong and functioning site-specific advisory board serves as a useful model for other DOE facilities, although the Fernald model is just one of many approaches that can be taken. However, the approach presented here has worked extremely well for Fernald

  5. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  6. Mobile Thread Task Manager

    Science.gov (United States)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  7. LHCb computing tasks

    CERN Document Server

    Binko, P

    1998-01-01

    This document describes the computing tasks of the LHCb computing system. It also describes the logistics of the dataflow between the tasks and the detailed requirements for each task, in particular the data sizes and CPU power requirements. All data sizes are calculated assuming that the LHCb experiment will take data about 107 s per year at a frequency of 200 Hz, which gives 2 \\Theta 109 real events per year. The raw event size should not exceed 100 kB (200 TB per year). We will have to generate about 109 MonteCarlo events per year. The current MonteCarlo simulation program based on the GEANT3.21 package requires about 12 s to produce an average event (all CPU times are normalised to a 1000 MIPS processor). The size of an average MonteCarlo event will be about 200 kB (100 TB per year) of simulated data (without the hits). We will start to use the GEANT4 package in 1998. Rejection factors of 8 and 25 are required in the Level-2 and Level-3 triggers respectively, to reduce the frequency of events to 200 Hz. T...

  8. Task analysis and support for problem solving tasks

    International Nuclear Information System (INIS)

    Bainbridge, L.

    1987-01-01

    This paper is concerned with Task Analysis as the basis for ergonomic design to reduce human error rates, rather than for predicting human error rates. Task Analysis techniques usually provide a set of categories for describing sub tasks, and a framework describing the relations between sub-tasks. Both the task type categories and their organisation have implications for optimum interface and training design. In this paper, the framework needed for considering the most complex tasks faced by operators in process industries is discussed such as fault management in unexpected situations, and what is likely to minimise human error in these circumstances. (author)

  9. Effects of noise and task loading on a communication task loading on a communication task

    Science.gov (United States)

    Orrell, Dean H., II

    Previous research had shown the effect of noise on a single communication task. This research has been criticized as not being representative of a real world situation since subjects allocated all of their attention to only one task. In the present study, the effect of adding a loading task to a standard noise-communication paradigm was investigated. Subjects performed both a communication task (Modified Rhyme Test; House et al. 1965) and a short term memory task (Sternberg, 1969) in simulated levels of aircraft noise (95, 105 and 115 dB overall sound pressure level (OASPL)). Task loading was varied with Sternberg's task by requiring subjects to memorize one, four, or six alphanumeric characters. Simulated aircraft noise was varied between levels of 95, 105 and 115 dB OASPL using a pink noise source. Results show that the addition of Sternberg's task and little effect on the intelligibility of the communication task while response time for the communication task increased.

  10. Scientific Research Program for Power, Energy, and Thermal Technologies. Task Order 0001: Energy, Power, and Thermal Technologies and Processes Experimental Research. Subtask: Thermal Management of Electromechanical Actuation System for Aircraft Primary Flight Control Surfaces

    Science.gov (United States)

    2014-05-01

    Computer FHPCP Flexible Heat Pipe Cold Plate HPEAS High Performance Electric Actuation System HPU Hydraulic Power Unit HSM Hydraulic Service...provide improved thermal paths and phase change materials offer energy storage. Loop heat pipes (LHP’s) and Flexible Heat Pipe Cold Plates (FHPCP’s...flows upward due to density difference through centrally located vapor channels called risers and then condenses on the colder surface associated

  11. The task-to-task communication between computers

    International Nuclear Information System (INIS)

    Lin Shuzi; Zhang Bingyun; Zhao Weiren

    1992-01-01

    The task-to-task communication is used in the Institute of High Energy Physics. The BES (Beijing Spectrometer) uses the communication mode to take some of the BEPC (Beijing Electron Positron Collider) running parameters needed by BES experiments in a periodic time. The authors describe the principle of transparent task-to-task communication and how to use it in BES on-line data acquisition system

  12. Children's Task Engagement during Challenging Puzzle Tasks

    Science.gov (United States)

    Wang, Feihong; Algina, James; Snyder, Patricia; Cox, Martha

    2017-01-01

    We examined children's task engagement during a challenging puzzle task in the presence of their primary caregivers by using a representative sample of rural children from six high-poverty counties across two states. Weighted longitudinal confirmatory factor analysis and structural equation modeling were used to identify a task engagement factor…

  13. Blink activity and task difficulty.

    Science.gov (United States)

    Tanaka, Y; Yamaoka, K

    1993-08-01

    This study investigated the relationship between task difficulty and blink activity, which includes blink rate, blink amplitude, and blink duration. Two kinds of tasks established two levels of difficulty. In Exp. 1, a mental arithmetic task was used to examine the relationship. Analysis showed that blink rate for a difficult task was significantly higher than that for an easier one. In Exp. 2, a letter-search task (hiragana Japanese alphabet) was used while the other conditions were the same as those in Exp. 1; however, the results of this experiment were not influenced by the difficulty of the task. As results indicate that blink rate is related to not only difficulty but also the nature of the task, the nature of the task is probably dependent on a mechanism in information processing. The results for blink amplitude and blink duration showed no systematic change during either experiment.

  14. Biology task group

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The accomplishments of the task group studies over the past year are reviewed. The purposes of biological investigations, in the context of subseabed disposal, are: an evaluation of the dose to man; an estimation of effects on the ecosystem; and an estimation of the influence of organisms on and as barriers to radionuclide migration. To accomplish these ends, the task group adopted the following research goals: (1) acquire more data on biological accumulation of specific radionuclides, such as those of Tc, Np, Ra, and Sr; (2) acquire more data on transfer coefficients from sediment to organism; (3) Calculate mass transfer rates, construct simple models using them, and estimate collective dose commitment; (4) Identify specific pathways or transfer routes, determine the rates of transfer, and make dose limit calculations with simple models; (5) Calculate dose rates to and estimate irradiation effects on the biota as a result of waste emplacement, by reference to background irradiation calculations. (6) Examine the effect of the biota on altering sediment/water radionuclide exchange; (7) Consider the biological data required to address different accident scenarios; (8) Continue to provide the basic biological information for all of the above, and ensure that the system analysis model is based on the most realistic and up-to-date concepts of marine biologists; and (9) Ensure by way of free exchange of information that the data used in any model are the best currently available

  15. Assessment of soil and groundwater contamination by potentially toxic and trace elements in an impounded vehicle scrapyard: Case study: Ribeirão Pires, SP, Brazil

    International Nuclear Information System (INIS)

    Lange, Camila Neves

    2018-01-01

    Impounded vehicle scrapyard (IVS) overcrowding is currently a subject of concern in Brazilian scenario. The aim of this study was to assess the total levels of potentially toxic elements (PTEs) and trace elements (TE) in soil and groundwater in an IVS located in the city of Ribeirão Pires. In order to achieve this objective, topsoil, three soil cores and groundwater of three monitoring wells were analyzed. It was verified that the area is mainly affected by three factors: (1) a landfill layer with construction waste; (2) an oily residue from past industrial activities in the area; (3) vehicles parked on topsoil. For the evaluation of the results, statistical techniques, such as multivariate analysis, calculation of pollution, ecological and human health risk index were used. Mass fractions of all PTEs, except Co, Cu, Mo and Zn, were higher than reference values. Hot spots were observed for most elements suggesting vehicular source. The Geoaccumulation Index showed minimal to moderate pollution in soil for most elements, except for As and Ba, which showed higher accumulation than other elements. The enrichment factor pointed to a significant enrichment of As and Pb. Arsenic content in soil may pose a moderate to high potential ecological risk. The results of PTEs and as statistical approaches indicated that As, Ce, Co, Cu, Mn, Nb, Ni, Pb and Zn are mainly from anthropogenic sources. The content of most PTEs in topsoil does not pose a potential human health risk, except Cr content. Groundwater levels for most PTEs were below the drinking water recommendation limits, except Mn and Fe content. (author)

  16. Records of pan (floodplain wetland) sedimentation as an approach for post-hoc investigation of the hydrological impacts of dam impoundment: The Pongolo river, KwaZulu-Natal.

    Science.gov (United States)

    Heath, S K; Plater, A J

    2010-07-01

    River impoundment by dams has far-reaching consequences for downstream floodplains in terms of hydrology, water quality, geomorphology, ecology and ecosystem services. With the imperative of economic development, there is the danger that potential environmental impacts are not assessed adequately or monitored appropriately. Here, an investigation of sediment composition of two pans (floodplain wetlands) in the Pongolo River floodplain, KwaZulu-Natal, downstream of the Pongolapoort dam constructed in 1974, is considered as a method for post-hoc assessment of the impacts on river hydrology, sediment supply and water quality. Bumbe and Sokhunti pans have contrasting hydrological regimes in terms of their connection to the main Pongolo channel - Bumbe is a shallow ephemeral pan and Sokhunti is a deep, perennial water body. The results of X-ray fluorescence (XRF) geochemical analysis of their sediment records over a depth of >1 m show that whilst the two pans exhibit similar sediment composition and variability in their lower part, Bumbe pan exhibits a shift toward increased fine-grained mineral supply and associated nutrient influx at a depth of c. 45 cm whilst Sokhunti pan is characterised by increased biogenic productivity at a depth of c. 26 cm due to enhanced nutrient status. The underlying cause is interpreted as a shift in hydrology to a 'post-dam' flow regime of reduced flood frequencies with more regular baseline flows which reduce the average flow velocity. In addition, Sokhunti shows a greater sensitivity to soil influx during flood events due to the nature of its 'background' of autochthonous biogenic sedimentation. The timing of the overall shift in sediment composition and the dates of the mineral inwash events are not well defined, but the potential for these wetlands as sensitive recorders of dam-induced changes in floodplain hydrology, especially those with a similar setting to Sokhunti pan, is clearly demonstrated. Copyright 2010 Elsevier Ltd. All

  17. Temporal changes in spatial patterns of submersed macrophytes in two impounded reaches of the Upper Mississippi River, USA, 1998-2009

    Science.gov (United States)

    De Jager, Nathan R.; Yin, Yao

    2011-01-01

    We examined temporal changes in spatial patterns of submersed aquatic macrophytes during a recent three-fold increase in macrophyte abundance and in response to the cumulative effects of management actions (island construction and water level management) and changes in regional environmental conditions (turbidity) in two navigation pools of the Upper Mississippi River, Pool 8 (managed) and Pool 13 (unmanaged). We used cross-correlograms to quantify changes in the degree and range of spatial correlation between submersed macrophytes and depth across the impounded portions of the two pools from 1998-2009. Along with increases in abundance, we observed gradual expansion of submersed macrophytes into deeper water in both pools. However, we detected no temporal change in spatial patterns in Pool 13, where the range of spatial correlation was ~ 1500-2500 m in length in the downriver direction and ~ 500-1000 m in length in the crossriver direction. We initially detected similar ranges of spatial correlation in Pool 8, but over time the range of correlation in the cross river direction increased from ~ 500 m in 1998 to ~ 2000 m by 2009. Thus, the expansion of submersed macrophytes into deeper water areas in Pool 8 appears to have occurred in the cross-river direction and led to increases in patch size and a more symmetrical patch configuration. Hence, very similar temporal changes in submersed macrophyte abundance corresponded with different diffusion dynamics and spatial patterns in the two pools. We hypothesize that management actions altered spatial patterns of depth, water flow and/or wind fetch and led to the differences in spatial patterns reported here.

  18. Sealing layer of fly ashes and sewage sludge and vegetation establishment in treatment of mine tailings impoundments; Flygaska och roetslam som taetskikt vid efterbehandling av sandmagasin med vegetationsetablering

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria; Neuschuetz, Clara [Stockholm Univ. (Sweden). Dept. of Botany; Isaksson, Karl-Erik [Boliden Mineral AB (Sweden)

    2006-02-15

    Each year the Swedish mining industry produces 25 Mtonnes of mine tailings that are disposed of in extensive natural impoundments. As this sand, containing more or less sulphide-rich minerals, is penetrated by oxygen and water, it starts weathering resulting in formation of acidic and metal-rich drainage water. To prevent oxygen penetration the mine tailings can be covered with a sealing layer covered with a protective cover that facilitates establishment of vegetation. The aim of this study has been to examine the function of fly ash and sewage sludge in sealing layers at impoundments of pyrite rich mine tailings, and the ability of different plant species, which are suitable for establishment in these areas, to penetrate the sealing layer with their roots and what impact they have on the drainage water. Experiments have been performed in field and greenhouse environment, with sealing layers consisting of fly ash and sewage sludge mixtures, covered with protective covers of sewage sludge or till. Plant establishment has been studied in a survey of naturally established plants at sewage sludge disposal sites close to mining areas, and by sowing and planting of selected plants, for instance fast growing grass species and fibre hemp at the test plots in field and in greenhouse experiments. Large scale application of ashes, sewage sludge and an ash/sludge mixture have been performed in field at three test plots with the size of 0.3-1 ha. Leakage of nutrients and metals from sealing layers has been studied in field and greenhouse tests. In addition, the ability of plant roots to penetrate sealing layers made of different ash/sludge mixtures have been examined in greenhouse experiments. This investigation is a cooperation between Stockholm University and Boliden Mineral AB, and the field experiments have been performed at the mine tailings impoundments at Gillervattnet, Boliden. Other collaborating participants are Skellefteaa Kraft and Munksund, who have produced the

  19. Selection of maintenance tasks

    Energy Technology Data Exchange (ETDEWEB)

    Dean, B; Rombos, P [Wardrop (W.L.) and Associates Ltd., Winnipeg, MB (Canada)

    1995-10-01

    Two methodologies for maintenance task selection, Reliability Centre Maintenance (RCM) and Degradation Mode Analysis (DMA), are compared with regard to application in the nuclear industry and potential for application at CANDU nuclear power plants. RCM is the favoured one of the two methodologies. It is more thorough than DMA, is well supported within the US nuclear industry, and - with experience in application - is gaining cost effectiveness. There is interest in the use of RCM in other nations, including France and Japan, and it is already being implemented at Bruce A NGS and Bruce B NGS in Canada. DMA lags behind RCM in development and currently there is little experience to support claims of major benefits at reduced cost. Significant advantages over RCM need to be demonstrated if DMA is to gain acceptance in the nuclear industry. (author). 41 refs., 7 tabs., 8 figs.

  20. Selection of maintenance tasks

    International Nuclear Information System (INIS)

    Dean, B.; Rombos, P.

    1995-10-01

    Two methodologies for maintenance task selection, Reliability Centre Maintenance (RCM) and Degradation Mode Analysis (DMA), are compared with regard to application in the nuclear industry and potential for application at CANDU nuclear power plants. RCM is the favoured one of the two methodologies. It is more thorough than DMA, is well supported within the US nuclear industry, and - with experience in application - is gaining cost effectiveness. There is interest in the use of RCM in other nations, including France and Japan, and it is already being implemented at Bruce A NGS and Bruce B NGS in Canada. DMA lags behind RCM in development and currently there is little experience to support claims of major benefits at reduced cost. Significant advantages over RCM need to be demonstrated if DMA is to gain acceptance in the nuclear industry. (author). 41 refs., 7 tabs., 8 figs

  1. Masticatory muscle activity during deliberately performed oral tasks

    International Nuclear Information System (INIS)

    Farella, M; Palla, S; Erni, S; Gallo, L M; Michelotti, A

    2008-01-01

    The aim of this study was to investigate masticatory muscle activity during deliberately performed functional and non-functional oral tasks. Electromyographic (EMG) surface activity was recorded unilaterally from the masseter, anterior temporalis and suprahyoid muscles in 11 subjects (5 men, 6 women; age = 34.6 ± 10.8 years), who were accurately instructed to perform 30 different oral tasks under computer guidance using task markers. Data were analyzed by descriptive statistics, repeated measurements analysis of variance (ANOVA) and hierarchical cluster analysis. The maximum EMG amplitude of the masseter and anterior temporalis muscles was more often found during hard chewing tasks than during maximum clenching tasks. The relative contribution of masseter and anterior temporalis changed across the tasks examined (F ≥ 5.2; p ≤ 0.001). The masseter muscle was significantly (p ≤ 0.05) more active than the anterior temporalis muscle during tasks involving incisal biting, jaw protrusion, laterotrusion and jaw cupping, the difference being statistically significant (p ≤ 0.05). The anterior temporalis muscle was significantly (p ≤ 0.01) more active than the masseter muscle during tasks performed in intercuspal position, during tooth grinding, and during hard chewing on the working side. Based upon the relative contribution of the masseter, anterior temporalis, and suprahyoid muscles, the investigated oral tasks could be grouped into six separate clusters. The findings provided further insight into muscle- and task-specific EMG patterns during functional and non-functional oral behaviors

  2. Functional Task Test: 1. Sensorimotor changes Associated with Postflight Alterations in Astronaut Functional Task Performance

    Science.gov (United States)

    Bloomberg, J. J.; Arzeno, N. H.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Platts, S. H.; Peters, B. T.; hide

    2011-01-01

    Space flight is known to cause alterations in multiple physiological systems including changes in sensorimotor, cardiovascular, and neuromuscular systems. These changes may affect a crewmember s ability to perform critical mission tasks immediately after landing on a planetary surface. The overall goal of this project is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. This presentation will focus on the sensorimotor contributions to postflight functional performance.

  3. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  4. Cognitive task load analysis : Allocating tasks and designing support

    NARCIS (Netherlands)

    Neerincx, M.A.

    2003-01-01

    We present a method for Cognitive Task Analysis that guides the early stages of software development, aiming at an optimal cognitive load for operators of process control systems. The method is based on a practical theory of cognitive task load and support. In addition to the classical measure

  5. Correlates of academic procrastination: discomfort, task aversiveness, and task capability.

    Science.gov (United States)

    Milgram, N; Marshevsky, S; Sadeh, C

    1995-03-01

    The relationships among five aspects of academic procrastination--behavioral delay, personal upset about the delay, task aversiveness, task capability, and the desire to reduce behavioral delay--were investigated in 10th-grade Israeli students (N = 195). Upset about delay was weakly related to delay itself, and--unlike delay--was strongly related to perceived capability to perform academic tasks and to the desire to change delaying behavior. Students delayed more on academic tasks labeled unpleasant than pleasant, were neutral in between, and were correspondingly more upset about the former than the latter. They more frequently acknowledged reasons for academic procrastination that were less threatening to their self-image (e.g., problems in time management) than reasons that were more threatening (e.g., lack of ability). Interest in reducing delay is related more to self-perceived ability to handle tasks than to time spent procrastinating or reasons given for procrastinating.

  6. Autonomous Inter-Task Transfer in Reinforcement Learning Domains

    Science.gov (United States)

    2008-08-01

    Mountain Car. However, because the source task uses a car with a motor more than twice as powerful as in the 3D task, the tran- sition function learned in...powerful car motor or changing the surface friction of the hill • s: changing the range of the state variables • si: changing where the car starts...Aamodt and Enric Plaza. Case-based reasoning: Foundational issues, methodological variations, and system approaches, 1994. Mazda Ahmadi, Matthew E

  7. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  8. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, van K.; Maanen, van P.P.

    2005-01-01

    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make

  9. Scheduling periodic tasks with slack

    NARCIS (Netherlands)

    Korst, J.H.M.; Aarts, E.H.L.; Lenstra, J.K.

    1997-01-01

    We consider the problem of nonpreemptively scheduling periodic tasks on a minimum number of identical processors, assuming that some slack is allowed in the time between successive executions of a periodic task. We prove that the problem is NP-hard in the strong sense. Necessary and sufficient

  10. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  11. Task-related modulation of visual neglect in cancellation tasks

    OpenAIRE

    Sarri, Margarita; Greenwood, Richard; Kalra, Lalit; Driver, Jon

    2008-01-01

    Unilateral neglect involves deficits of spatial exploration and awareness that do not always affect a fixed portion of extrapersonal space, but may vary with current stimulation and possibly with task demands. Here, we assessed any ‘top-down’, task-related influences on visual neglect, with novel experimental variants of the cancellation test. Many different versions of the cancellation test are used clinically, and can differ in the extent of neglect revealed, though the exact factors determ...

  12. Generic task problem descriptions: Category B, C, and D tasks

    International Nuclear Information System (INIS)

    1978-06-01

    This document contains information relating to Category B, C, and D generic technical activities. The specific information provided for each task includes the reactor type to which the generic issue applies, the NRC division with lead responsibility and a description of the problem to be addressed by the task. Also provided in this document is a listing of Category A generic technical activities and definitions of Priority Categories A, B, C, and D

  13. Performance Enhancements Under Dual-task Conditions

    Science.gov (United States)

    Kramer, A. F.; Wickens, C. D.; Donchin, E.

    1984-01-01

    Research on dual-task performance has been concerned with delineating the antecedent conditions which lead to dual-task decrements. Capacity models of attention, which propose that a hypothetical resource structure underlies performance, have been employed as predictive devices. These models predict that tasks which require different processing resources can be more successfully time shared than tasks which require common resources. The conditions under which such dual-task integrality can be fostered were assessed in a study in which three factors likely to influence the integrality between tasks were manipulated: inter-task redundancy, the physical proximity of tasks and the task relevant objects. Twelve subjects participated in three experimental sessions in which they performed both single and dual-tasks. The primary task was a pursuit step tracking task. The secondary tasks required the discrimination between different intensities or different spatial positions of a stimulus. The results are discussed in terms of a model of dual-task integrality.

  14. Quantum tasks in Minkowski space

    International Nuclear Information System (INIS)

    Kent, Adrian

    2012-01-01

    The fundamental properties of quantum information and its applications to computing and cryptography have been greatly illuminated by considering information-theoretic tasks that are provably possible or impossible within non-relativistic quantum mechanics. I describe here a general framework for defining tasks within (special) relativistic quantum theory and illustrate it with examples from relativistic quantum cryptography and relativistic distributed quantum computation. The framework gives a unified description of all tasks previously considered and also defines a large class of new questions about the properties of quantum information in relation to Minkowski causality. It offers a way of exploring interesting new fundamental tasks and applications, and also highlights the scope for a more systematic understanding of the fundamental information-theoretic properties of relativistic quantum theory. (paper)

  15. When Task Conflict Becomes Personal

    Science.gov (United States)

    Guenter, Hannes; van Emmerik, Hetty; Schreurs, Bert; Kuypers, Tom; van Iterson, Ad; Notelaers, Guy

    2016-01-01

    Although potentially beneficial, task conflict may threaten teams because it often leads to relationship conflict. Prior research has identified a set of interpersonal factors (e.g., team communication, team trust) that help attenuate this association. The purpose of this article is to provide an alternative perspective that focuses on the moderating role of performance-related factors (i.e., perceived team performance). Using social identity theory, we build a model that predicts how task conflict associates with growth in relationship conflict and how perceived team performance influences this association. We test a three-wave longitudinal model by means of random coefficient growth modeling, using data from 60 ongoing teams working in a health care organization. Results provide partial support for our hypotheses. Only when perceived team performance is low, do task conflicts relate with growth in relationship conflict. We conclude that perceived team performance seems to enable teams to uncouple task from relationship conflict. PMID:28190944

  16. Depletion of barium and radium-226 in Black Sea surface waters over the past thirty years

    International Nuclear Information System (INIS)

    Kenison Falkner, K.K.; Edmond, J.M.; O'Neill, D.J.; Todd, J.F.; Moore, W.S.

    1991-01-01

    The nearly landlocked waters of the Black Sea support a valuable fishery, but are also particularly vulnerable to anthropogenic disturbance. Here we use dissolved barium and radium-226 as tracers, to investigate the biogeochemical health of the sea. Both elements are brought to surface waters by vertical mixing of deeper, enriched waters, and by rivers; these inputs should ordinarily be balanced by outflow of surface waters at the Bosphorus, and by biologically mediated removal of 226 Ra-bearing barite. We show, however, that surface-water inventories have been substantially depleted over the past few decades: recent (1988-89) barium concentrations were 1.6 times lower than in 1958 and 1967. These observations suggest that steady-state cycling of these elements has been perturbed by increased primary productivity, presumably fuelled by nutrients from industry and agricultural runoff, and to a lesser extent by decreased fluvial sediment loads owing to extensive impoundment of rivers in the region. (author)

  17. Annual Progress report - General Task

    International Nuclear Information System (INIS)

    Wesnousky, S.G.

    1993-01-01

    This report provides a summary of progress for the project open-quotes Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).close quotes A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks

  18. Measuring Multi-tasking Ability

    Science.gov (United States)

    2003-07-01

    sociological factors pertaining to social structures and values. For example, telecommuting , job-sharing, and families’ attempts to decrease the amount...achievement strivings (actively working hard to achieve goals), and poly- chronicity ( the preference for working on more than one task at a time) with MT...Joslyn note (2000), this description of ADM makes it sound exceedingly easy. However, nothing could be farther from the truth . The task qualifies as an MT

  19. Graphical programming of telerobotic tasks

    International Nuclear Information System (INIS)

    Small, D.E.; McDonald, M.J.

    1997-01-01

    With a goal of producing faster, safer, and cheaper technologies for nuclear waste cleanup, Sandia is actively developing and extending intelligent systems technologies. Graphical Programming is a key technology for robotic waste cleanup that Sandia is developing for this goal. This paper describes Sancho, Sandia most advanced Graphical Programming supervisory software. Sancho, now operational on several robot systems, incorporates all of Sandia's recent advances in supervisory control. Sancho, developed to rapidly apply Graphical Programming on a diverse set of robot systems, uses a general set of tools to implement task and operational behavior. Sancho can be rapidly reconfigured for new tasks and operations without modifying the supervisory code. Other innovations include task-based interfaces, event-based sequencing, and sophisticated GUI design. These innovations have resulted in robot control programs and approaches that are easier and safer to use than teleoperation, off-line programming, or full automation

  20. Computer-Related Task Performance

    DEFF Research Database (Denmark)

    Longstreet, Phil; Xiao, Xiao; Sarker, Saonee

    2016-01-01

    The existing information system (IS) literature has acknowledged computer self-efficacy (CSE) as an important factor contributing to enhancements in computer-related task performance. However, the empirical results of CSE on performance have not always been consistent, and increasing an individual......'s CSE is often a cumbersome process. Thus, we introduce the theoretical concept of self-prophecy (SP) and examine how this social influence strategy can be used to improve computer-related task performance. Two experiments are conducted to examine the influence of SP on task performance. Results show...... that SP and CSE interact to influence performance. Implications are then discussed in terms of organizations’ ability to increase performance....

  1. Musical Tasks and Energetic Arousal.

    Science.gov (United States)

    Lim, Hayoung A; Watson, Angela L

    2018-03-08

    Music is widely recognized as a motivating stimulus. Investigators have examined the use of music to improve a variety of motivation-related outcomes; however, these studies have focused primarily on passive music listening rather than active participation in musical activities. To examine the influence of participation in musical tasks and unique participant characteristics on energetic arousal. We used a one-way Welch's ANOVA to examine the influence of musical participation (i.e., a non-musical control and four different musical task conditions) upon energetic arousal. In addition, ancillary analyses of participant characteristics including personality, age, gender, sleep, musical training, caffeine, nicotine, and alcohol revealed their possible influence upon pretest and posttest energetic arousal scores. Musical participation yielded a significant relationship with energetic arousal, F(4, 55.62) = 44.38, p = .000, estimated ω2 = 0.60. Games-Howell post hoc pairwise comparisons revealed statistically significant differences between five conditions. Descriptive statistics revealed expected differences between introverts' and extraverts' energetic arousal scores at the pretest, F(1, 115) = 6.80, p = .010, partial η2= .06; however, mean differences failed to reach significance at the posttest following musical task participation. No other measured participant characteristics yielded meaningful results. Passive tasks (i.e., listening to a story or song) were related to decreased energetic arousal, while active musical tasks (i.e., singing, rhythm tapping, and keyboard playing) were related to increased energetic arousal. Musical task participation appeared to have a differential effect for individuals with certain personality traits (i.e., extroverts and introverts).

  2. Underground coal mine subsidence impacts on surface water

    International Nuclear Information System (INIS)

    Stump, D.E. Jr.

    1992-01-01

    This paper reports that subsidence from underground coal mining alters surface water discharge and availability. The magnitude and areal extent of these impacts are dependent on many factors, including the amount of subsidence, topography, geology, climate, surface water - ground water interactions, and fractures in the overburden. There alterations may have positive and/or negative impacts. One of the most significant surface water impacts occurred in July 1957 near West Pittston, Pennsylvania. Subsidence in the Knox Mine under the Coxton Yards of the Lehigh Valley Railroad allowed part of the discharge in the Susquehanna River to flow into the mine and create a crater 200 feet in diameter and 300 feet deep. Fourteen railroad gondola cars fell into the hole which was eventually filled with rock, sand, and gravel. Other surface water impacts from subsidence may include the loss of water to the ground water system, the gaining of water from the ground water system, the creation of flooded subsidence troughs, the increasing of impoundment storage capacity, the relocation of water sources (springs), and the alteration of surface drainage patterns

  3. Job Management and Task Bundling

    Science.gov (United States)

    Berkowitz, Evan; Jansen, Gustav R.; McElvain, Kenneth; Walker-Loud, André

    2018-03-01

    High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users' current workflows or executables.

  4. Job Management and Task Bundling

    Directory of Open Access Journals (Sweden)

    Berkowitz Evan

    2018-01-01

    Full Text Available High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users’ current workflows or executables.

  5. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

    Nielsen, Jan; Jacobsen, Claus Haugaard; Mathiesen, Birgit Bork

    2012-01-01

    were confronted with complicated jobs, e.g., group, internal and interdisciplinary supervision, but were not prepared, i.e. trained, prior to these tasks. These findings imply that more training is needed for novice supervisors. Preferably, this training should be introduced before, or at least...... Questionnaire covering a wide range of items on professional development, experience, and practice. In this paper we focus on background data (experience, training and practice), specifically the tasks and training of the respondents as novice supervisors. The results show, that a majority of novice supervisors...

  6. 78 FR 63208 - UPDATE-Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-10-23

    ... of the Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and... Community Preventive Services Task Force (Task Force). The in-person Task Force meeting is being replaced by... CDC's ability to complete the necessary scientific and logistical support for the meeting. The Task...

  7. 78 FR 2996 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-01-15

    ... Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention... Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally.... The Task Force was convened in 1996 by the Department of Health and Human Services (HHS) to assess the...

  8. 77 FR 56845 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2012-09-14

    ... Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention... Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally.... The Task Force was convened in 1996 by the Department of Health and Human Services (HHS) to assess the...

  9. 78 FR 27969 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-05-13

    ... Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention... Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally.... The Task Force was convened in 1996 by the Department of Health and Human Services (HHS) to assess the...

  10. The Wikipedia Image Retrieval Task

    NARCIS (Netherlands)

    T. Tsikrika (Theodora); J. Kludas

    2010-01-01

    htmlabstractThe wikipedia image retrieval task at ImageCLEF provides a testbed for the system-oriented evaluation of visual information retrieval from a collection of Wikipedia images. The aim is to investigate the effectiveness of retrieval approaches that exploit textual and visual evidence in the

  11. A Population of Assessment Tasks

    Science.gov (United States)

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  12. NASA's Big Data Task Force

    Science.gov (United States)

    Holmes, C. P.; Kinter, J. L.; Beebe, R. F.; Feigelson, E.; Hurlburt, N. E.; Mentzel, C.; Smith, G.; Tino, C.; Walker, R. J.

    2017-12-01

    Two years ago NASA established the Ad Hoc Big Data Task Force (BDTF - https://science.nasa.gov/science-committee/subcommittees/big-data-task-force), an advisory working group with the NASA Advisory Council system. The scope of the Task Force included all NASA Big Data programs, projects, missions, and activities. The Task Force focused on such topics as exploring the existing and planned evolution of NASA's science data cyber-infrastructure that supports broad access to data repositories for NASA Science Mission Directorate missions; best practices within NASA, other Federal agencies, private industry and research institutions; and Federal initiatives related to big data and data access. The BDTF has completed its two-year term and produced several recommendations plus four white papers for NASA's Science Mission Directorate. This presentation will discuss the activities and results of the TF including summaries of key points from its focused study topics. The paper serves as an introduction to the papers following in this ESSI session.

  13. Who Multi-Tasks and Why? Multi-Tasking Ability, Perceived Multi-Tasking Ability, Impulsivity, and Sensation Seeking

    OpenAIRE

    Sanbonmatsu, David M.; Strayer, David L.; Medeiros-Ward, Nathan; Watson, Jason M.

    2013-01-01

    The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are ...

  14. Attentional Demands of Balance Under Dual Task Conditions in Young Adults

    Directory of Open Access Journals (Sweden)

    Monire Nobahar Ahari

    2012-10-01

    Full Text Available Objectives: The aim of this study was to identify the role of attentional process in postural control using choice reaction time task while changing the visual and proprioceptive cues under difficult balance task (standing on one-leg. Methods: This cross-sectional study was conducted by participating 20 young people (22.75±2.29. Each subject performed one-leg standing as balance task for each of the following 2 test conditions: free balance position (single task, and balancing while performing secondary cognitive task (choice reaction time task. Each test was carried out for each of the following 3 sensory conditions: on hard surface with open eyes, on hard surface with closed eyes and on foam surface with closed eyes. One way ANOVA was used for analysis. Results: Analyses of the task conditions didn’t show significant difference between single and dual task under two sensory conditions, in open and in closed eye on hard surface (P>0.05, but there was significant difference between single and dual tasks on soft foam with closed eyes [t(19=-2.391, P=0.027]. Discussion: Findings revealed that significant difference in balance performance of individuals under three different sensory conditions caused by reduction in base of support and this effect can be seen in dual task condition as well. Therefore it can be concluded that the nature of the primary task have the most influence on balance performance and this is not the effect of dual task condition.

  15. Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking.

    Science.gov (United States)

    Sanbonmatsu, David M; Strayer, David L; Medeiros-Ward, Nathan; Watson, Jason M

    2013-01-01

    The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants' perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation--high levels of impulsivity and sensation seeking--reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control--low scorers on the Operation Span task and persons high in impulsivity--tended to report higher levels of multi-tasking activity.

  16. Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking.

    Directory of Open Access Journals (Sweden)

    David M Sanbonmatsu

    Full Text Available The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants' perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation--high levels of impulsivity and sensation seeking--reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control--low scorers on the Operation Span task and persons high in impulsivity--tended to report higher levels of multi-tasking activity.

  17. Who Multi-Tasks and Why? Multi-Tasking Ability, Perceived Multi-Tasking Ability, Impulsivity, and Sensation Seeking

    Science.gov (United States)

    Sanbonmatsu, David M.; Strayer, David L.; Medeiros-Ward, Nathan; Watson, Jason M.

    2013-01-01

    The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants’ perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation – high levels of impulsivity and sensation seeking – reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control - low scorers on the Operation Span task and persons high in impulsivity - tended to report higher levels of multi-tasking activity. PMID:23372720

  18. Overview of NTCIR-12 Lifelog Task

    OpenAIRE

    Gurrin, Cathal; Joho, Hideo; Hopfgartner, Frank; Zhou, Liting; Albatal, Rami

    2016-01-01

    In this paper we review the NTCIR12-Lifelog pilot task,\\ud which ran at NTCIR-12. We outline the test collection employed,\\ud along with the tasks, the eight submissions and the\\ud findings from this pilot task. We finish by suggesting future\\ud plans for the task.

  19. Development of advanced MCR task analysis methods

    International Nuclear Information System (INIS)

    Na, J. C.; Park, J. H.; Lee, S. K.; Kim, J. K.; Kim, E. S.; Cho, S. B.; Kang, J. S.

    2008-07-01

    This report describes task analysis methodology for advanced HSI designs. Task analyses was performed by using procedure-based hierarchical task analysis and task decomposition methods. The results from the task analysis were recorded in a database. Using the TA results, we developed static prototype of advanced HSI and human factors engineering verification and validation methods for an evaluation of the prototype. In addition to the procedure-based task analysis methods, workload estimation based on the analysis of task performance time and analyses for the design of information structure and interaction structures will be necessary

  20. Survival Processing and the Stroop Task

    OpenAIRE

    Stephanie A. Kazanas; Kendra M. Van Valkenburg; Jeanette Altarriba

    2015-01-01

    This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an importa...

  1. Procedural Error and Task Interruption

    Science.gov (United States)

    2016-09-30

    interruption. A cognitive model we discuss below explains this effect in terms of increases in performance speed having the effect of compressing memory for...performance, and pilot data suggest that the task can distinguish between cognitive processes that are impaired by sleep deprivation and those that are...David Z. Hambrick Technical contact: Erik M. Altmann Michigan State University Department of Psychology 316 Physics Rd, Room 298A East Lansing

  2. Measurement of functional task difficulty during motor learning: What level of difficulty corresponds to the optimal challenge point?

    Science.gov (United States)

    Akizuki, Kazunori; Ohashi, Yukari

    2015-10-01

    The relationship between task difficulty and learning benefit was examined, as was the measurability of task difficulty. Participants were required to learn a postural control task on an unstable surface at one of four different task difficulty levels. Results from the retention test showed an inverted-U relationship between task difficulty during acquisition and motor learning. The second-highest level of task difficulty was the most effective for motor learning, while learning was delayed at the most and least difficult levels. Additionally, the results indicate that salivary α-amylase and the performance dimension of the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) are useful indices of task difficulty. Our findings suggested that instructors may be able to adjust task difficulty based on salivary α-amylase and the performance dimension of the NASA-TLX to enhance learning. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Kokkos' Task DAG Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Harold C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ibanez, Daniel Alejandro [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Task DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.

  4. Investigating Antecedents of Task Commitment and Task Attraction in Service Learning Team Projects

    Science.gov (United States)

    Schaffer, Bryan S.; Manegold, Jennifer G.

    2018-01-01

    The authors investigated the antecedents of team task cohesiveness in service learning classroom environments. Focusing on task commitment and task attraction as key dependent variables representing cohesiveness, and task interdependence as the primary independent variable, the authors position three important task action phase processes as…

  5. Investigating Perfect Timesharing: The Relationship between IM-Compatible Tasks and Dual-Task Performance

    Science.gov (United States)

    Halvorson, Kimberly M.; Ebner, Herschel; Hazeltine, Eliot

    2013-01-01

    Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two…

  6. 78 FR 59939 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-09-30

    ... Community Preventive Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention... September 17, 2013, announcing the next meeting of the Community Preventive Services Task Force (Task Force... the Task Force to consider the findings of systematic reviews and issue findings and recommendations...

  7. The effects of stimulus modality and task integrality: Predicting dual-task performance and workload from single-task levels

    Science.gov (United States)

    Hart, S. G.; Shively, R. J.; Vidulich, M. A.; Miller, R. C.

    1986-01-01

    The influence of stimulus modality and task difficulty on workload and performance was investigated. The goal was to quantify the cost (in terms of response time and experienced workload) incurred when essentially serial task components shared common elements (e.g., the response to one initiated the other) which could be accomplished in parallel. The experimental tasks were based on the Fittsberg paradigm; the solution to a SternBERG-type memory task determines which of two identical FITTS targets are acquired. Previous research suggested that such functionally integrated dual tasks are performed with substantially less workload and faster response times than would be predicted by suming single-task components when both are presented in the same stimulus modality (visual). The physical integration of task elements was varied (although their functional relationship remained the same) to determine whether dual-task facilitation would persist if task components were presented in different sensory modalities. Again, it was found that the cost of performing the two-stage task was considerably less than the sum of component single-task levels when both were presented visually. Less facilitation was found when task elements were presented in different sensory modalities. These results suggest the importance of distinguishing between concurrent tasks that complete for limited resources from those that beneficially share common resources when selecting the stimulus modalities for information displays.

  8. Upper Limb Muscle and Brain Activity in Light Assembly Task on Different Load Levels

    Science.gov (United States)

    Zadry, Hilma Raimona; Dawal, Siti Zawiah Md.; Taha, Zahari

    2010-10-01

    A study was conducted to investigate the effect of load on upper limb muscles and brain activities in light assembly task. The task was conducted at two levels of load (Low and high). Surface electromyography (EMG) was used to measure upper limb muscle activities of twenty subjects. Electroencephalography (EEG) was simultaneously recorded with EMG to record brain activities from Fz, Pz, O1 and O2 channels. The EMG Mean Power Frequency (MPF) of the right brachioradialis and the left upper trapezius activities were higher on the high-load task compared to low-load task. The EMG MPF values also decrease as time increases, that reflects muscle fatigue. Mean power of the EEG alpha bands for the Fz-Pz channels were found to be higher on the high-load task compared to low-load task, while for the O1-O2 channels, they were higher on the low-load task than on the high-load task. These results indicated that the load levels effect the upper limb muscle and brain activities. The high-load task will increase muscle activities on the right brachioradialis and the left upper tapezius muscles, and will increase the awareness and motivation of the subjects. Whilst the low-load task can generate drowsiness earlier. It signified that the longer the time and the more heavy of the task, the subjects will be more fatigue physically and mentally.

  9. Brain activations during bimodal dual tasks depend on the nature and combination of component tasks

    Directory of Open Access Journals (Sweden)

    Emma eSalo

    2015-02-01

    Full Text Available We used functional magnetic resonance imaging to investigate brain activations during nine different dual tasks in which the participants were required to simultaneously attend to concurrent streams of spoken syllables and written letters. They performed a phonological, spatial or simple (speaker-gender or font-shade discrimination task within each modality. We expected to find activations associated specifically with dual tasking especially in the frontal and parietal cortices. However, no brain areas showed systematic dual task enhancements common for all dual tasks. Further analysis revealed that dual tasks including component tasks that were according to Baddeley’s model modality atypical, that is, the auditory spatial task or the visual phonological task, were not associated with enhanced frontal activity. In contrast, for other dual tasks, activity specifically associated with dual tasking was found in the left or bilateral frontal cortices. Enhanced activation in parietal areas, however, appeared not to be specifically associated with dual tasking per se, but rather with intermodal attention switching. We also expected effects of dual tasking in left frontal supramodal phonological processing areas when both component tasks required phonological processing and in right parietal supramodal spatial processing areas when both tasks required spatial processing. However, no such effects were found during these dual tasks compared with their component tasks performed separately. Taken together, the current results indicate that activations during dual tasks depend in a complex manner on specific demands of component tasks.

  10. NATO SCEPC functions and tasks

    International Nuclear Information System (INIS)

    Somer, E.

    1998-01-01

    The main functions and tasks for Civil Emergency Planning Directorate of NATO are presented. As a support and complement of United Nations Europ-Atlantic Partnership Council established a regional arrangement - a Europ-Atlantic Disaster Response capability with Coordination Center at NATO headquarters. Responsibility for disaster response is with the stricken nation while Europ-Atlantic Partnership Council role is one of coordination rather than direction. Europ-Atlantic Disaster Response Coordination Center act as focal point for information sharing on disaster assistance request among Europ-Atlantic Partnership Council countries. NATO Civil Emergency Planning Directorate consists of representatives from Europ-Atlantic Partnership Council countries and United Nations liaison officer

  11. Task-based exposure assessment of nanoparticles in the workplace

    International Nuclear Information System (INIS)

    Ham, Seunghon; Yoon, Chungsik; Lee, Euiseung; Lee, Kiyoung; Park, Donguk; Chung, Eunkyo; Kim, Pilje; Lee, Byoungcheun

    2012-01-01

    Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

  12. Influence of time pressure in a simple response task, a choice-by-location task, and the Simon task

    NARCIS (Netherlands)

    van der Lubbe, Robert Henricus Johannes; Jaśkowski, Piotr; Wauschkuhn, Bernd; Verleger, Rolf

    2001-01-01

    Examined the influence of strategy for a simple response task, a choice-by-location task, and the Simon task by varying time pressure in 11 Ss (mean age 28 yrs). Besides reaction time (RT) and accuracy, we measured response force and derived two measures from the event-related EEG potential to form

  13. The BOLD Response during Stroop Task-Like Inhibition Paradigms: Effects of Task Difficulty and Task-Relevant Modality

    Science.gov (United States)

    Mitchell, Rachel L. C.

    2005-01-01

    Previous studies of the Stroop task propose two key mediators: the prefrontal and cingulate cortices but hints exist of functional specialization within these regions. This study aimed to examine the effect of task modality upon the prefrontal and cingulate response by examining the response to colour, number, and shape Stroop tasks whilst BOLD…

  14. A design space of visualization tasks.

    Science.gov (United States)

    Schulz, Hans-Jörg; Nocke, Thomas; Heitzler, Magnus; Schumann, Heidrun

    2013-12-01

    Knowledge about visualization tasks plays an important role in choosing or building suitable visual representations to pursue them. Yet, tasks are a multi-faceted concept and it is thus not surprising that the many existing task taxonomies and models all describe different aspects of tasks, depending on what these task descriptions aim to capture. This results in a clear need to bring these different aspects together under the common hood of a general design space of visualization tasks, which we propose in this paper. Our design space consists of five design dimensions that characterize the main aspects of tasks and that have so far been distributed across different task descriptions. We exemplify its concrete use by applying our design space in the domain of climate impact research. To this end, we propose interfaces to our design space for different user roles (developers, authors, and end users) that allow users of different levels of expertise to work with it.

  15. U.S. Preventive Services Task Force

    Science.gov (United States)

    ... USPSTF Our Members Conflict of Interest Disclosures Task Force Resources Our Partners Reports to Congress Contact Us ... effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and its processes more transparent, ...

  16. Pre-task music improves swimming performance.

    Science.gov (United States)

    Smirmaul, B P; Dos Santos, R V; Da Silva Neto, L V

    2015-12-01

    The purpose of this study was to investigate the effects of pre-task music on swimming performance and other psychological variables. A randomized counterbalanced within-subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200-m freestyle swimming time trials. Participants were exposed to either 5 minutes of self-selected music (pre-task music condition) or 5 minutes of silence (control condition) and, after 1 minute, performed the swimming task. Swimming time was significantly shorter (-1.44%) in the pre-task music condition. Listening to pre-task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigor, ratings of perceived exertion and affective valence were unaltered. It is concluded, for the first time, that pre-task music improves swimming performance.

  17. The IUGS/IAGC Task Group on Global Geochemical Baselines

    Science.gov (United States)

    Smith, David B.; Wang, Xueqiu; Reeder, Shaun; Demetriades, Alecos

    2012-01-01

    The Task Group on Global Geochemical Baselines, operating under the auspices of both the International Union of Geological Sciences (IUGS) and the International Association of Geochemistry (IAGC), has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth’s surface or near-surface environment. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified. In order to accomplish this long-term goal, the activities of the Task Group include: (1) developing partnerships with countries conducting broad-scale geochemical mapping studies; (2) providing consultation and training in the form of workshops and short courses; (3) organizing periodic international symposia to foster communication among the geochemical mapping community; (4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database; (5) acting as a repository for data collected by those projects meeting the criteria for standardization; (6) preparing complete metadata for the certified projects; and (7) preparing, ultimately, a global geochemical database. This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

  18. An overview of task order 10

    Energy Technology Data Exchange (ETDEWEB)

    Rousculp, Christopher L [Los Alamos National Laboratory

    2011-01-12

    Task Order 10 formalizes a collaboration in high explosive pulsed power (HEPP) experiments between LANL and VNIIEF. The focus is the VNIIEF disk explosive magnetic generator (DEMG) technology. The task order outlines a sequence of tasks and deliverables culminating in an experiment which takes place in the US utilizing US explosives and a Russian DEMG. This talk summarizes task order 10. It gives a brief history and present status in terms of the proposed high pressure EOS experiment (ALT-3).

  19. The Factor Structure of Some Piagetian Tasks

    Science.gov (United States)

    Lawson, Anton E.; Nordland, Floyd H.

    1976-01-01

    Investigated was the hypothesis that conservation tasks are unifactor by administering eight different conservation tasks to 96 seventh-grade science students and performing a principal component analysis on the data. Results indicated that conservation tasks may measure up to three different components of cognitive thought. (SL)

  20. Task Manager for the Motorola 6800

    International Nuclear Information System (INIS)

    Merillat, P.D.

    1979-05-01

    A nucleus of multi-tasking operating systems has been implemented on a Motorola 6800 microprocessor. This control structure, called a Task Manager, is appropriate for those real-time systems which are required to handle several different asynchronous events. The general concept of a Task Manager is described. A specific implementation for a Motorola 6800 microprocessor is given and its usage defined

  1. Teaching Task Sequencing via Verbal Mediation.

    Science.gov (United States)

    Rusch, Frank R.; And Others

    1987-01-01

    Verbal sequence training was used to teach a moderately mentally retarded woman to sequence job-related tasks. Learning to say the tasks in the proper sequence resulted in the employee performing her tasks in that sequence, and the employee was capable of mediating her own work behavior when scheduled changes occurred. (Author/JDD)

  2. What Makes a Mathematical Task Interesting?

    Science.gov (United States)

    Nyman, Rimma

    2016-01-01

    The study addresses the question of what makes a mathematical task interesting to the 9th year students. Semi-structured interviews were carried out with 15 students of purposive selection of the 9th year. The students were asked to recall a task they found interesting and engaging during the past three years. An analysis of the tasks was made…

  3. Surface and subsurface soils at the Pond B dam: July 1998

    International Nuclear Information System (INIS)

    Halverson, N.V.

    1999-01-01

    Pond B, 685-13G, is an inactive reactor cooling impoundment built in 1961 on the Savannah River Site (SRS). Between 1961 and 1964, Pond B received R-Reactor cooling water discharges that were contaminated with 137 Cs, 90 Sr and plutonium. Though the pond has not been used since 1964, radionuclides from the contaminated cooling water remain in the water and in the surface sediments of the pond. The current proposal to fix and repair the Pond B dam structure includes installing a new drain system and monitoring equipment. The dam will be reinforced with additional previous material on the downstream face of the dam. The objectives of this report are to describe the sampling methodology used during the July 1998 sampling event at the downstream face of the Pond B dam and in Pond B, present the results of the sampling event, and compare, where possible, these results to related risk-based standards

  4. Effects of Task Complexity, Task Conditions, and Task Difficulty on the Grammatical Accuracy of EFL Learners in Written Discourse

    Directory of Open Access Journals (Sweden)

    Saeideh Ahangari

    2012-11-01

    Full Text Available Different methods of language teaching have tried to help EFL learners to develop good language skills based on their various perspectives. Research findings have underscored the effect of using task types in promoting language skills in terms of accuracy in written discourse. Therefore, this study set out to investigate whether there is an evidence of correct use of simple past tense (Accuracy based on Task Complexity (Task type :Here-and now & There-and-then,Task Conditions (Gender: Male & Female, and Task Difficulty (Proficiency: Lower-intermediate & Intermediate. Sixty Iranian English learners in a language institute participated in the study and were assigned to four groups of lower-intermediate male, lower-intermediate female, intermediate male and intermediate female. Initial homogeneity of the groups was verified using two general proficiency tests; KET for lower-intermediate and PET for intermediate. All groups in here-and-now task type were asked to write a story using simple past based on a picture strip while for there-and-then task type the participants were supposed to write about their last birthday. The results from paired samples t-test, independent samples t-test and two-way ANOVA analysis of the written data revealed significant differences in performing task types, at different proficiency levels and interaction between them. The findings have significant pedagogical implications for EFL learners to understand the relationship among Task Complexity,Task Conditions, Task Difficulty and L2 written production leading to various degrees of Accuracy.

  5. Resolving task rule incongruence during task switching by competitor rule suppression.

    Science.gov (United States)

    Meiran, Nachshon; Hsieh, Shulan; Dimov, Eduard

    2010-07-01

    Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires fine-tuned inhibition that impairs task readiness only minimally. In an experiment involving 2 object classification tasks and 2 location classification tasks, the authors show that irrelevant task rules that generate response conflicts are inhibited. This competitor rule suppression (CRS) is seen in response slowing in subsequent trials, when the competing rules become relevant. CRS is shown to operate on specific rules without affecting similar rules. CRS and backward inhibition, which is another inhibitory phenomenon, produced additive effects on reaction time, suggesting their mutual independence. Implications for current formal theories of task switching as well as for conflict monitoring theories are discussed. (c) 2010 APA, all rights reserved

  6. Working Memory Training Improves Dual-Task Performance on Motor Tasks.

    Science.gov (United States)

    Kimura, Takehide; Kaneko, Fuminari; Nagahata, Keita; Shibata, Eriko; Aoki, Nobuhiro

    2017-01-01

    The authors investigated whether working memory training improves motor-motor dual-task performance consisted of upper and lower limb tasks. The upper limb task was a simple reaction task and the lower limb task was an isometric knee extension task. 45 participants (age = 21.8 ± 1.6 years) were classified into a working memory training group (WM-TRG), dual-task training group, or control group. The training duration was 2 weeks (15 min, 4 times/week). Our results indicated that working memory capacity increased significantly only in the WM-TRG. Dual-task performance improved in the WM-TRG and dual-task training group. Our study provides the novel insight that working memory training improves dual-task performance without specific training on the target motor task.

  7. Laser Cleaning of Contaminated Painted Surfaces. Semiannual report, November 1, 1996--March 31, 1997

    International Nuclear Information System (INIS)

    Grisanti, Ames A.; Jensen, Robert R.

    1997-01-01

    The objective of this project is to develop a software tool for use by personnel who must select a surface decontamination technique. The software will incorporate performance data for available surface decontamination techniques. The major activities in the project are broken down as follows: Task 1 - Complete decision tree development. Task 2 - Literature search for surface decontamination reports. Task 3 - Compilation of database from literature data. Task 4 - Sensitivity analysis and model design. Task 5 - Design of model data structures. Task 6 - PC software design and coding

  8. Minimal surfaces

    CERN Document Server

    Dierkes, Ulrich; Sauvigny, Friedrich; Jakob, Ruben; Kuster, Albrecht

    2010-01-01

    Minimal Surfaces is the first volume of a three volume treatise on minimal surfaces (Grundlehren Nr. 339-341). Each volume can be read and studied independently of the others. The central theme is boundary value problems for minimal surfaces. The treatise is a substantially revised and extended version of the monograph Minimal Surfaces I, II (Grundlehren Nr. 295 & 296). The first volume begins with an exposition of basic ideas of the theory of surfaces in three-dimensional Euclidean space, followed by an introduction of minimal surfaces as stationary points of area, or equivalently

  9. NCRP soil contamination task group

    International Nuclear Information System (INIS)

    Jacobs, D.G.

    1987-01-01

    The National Council of Radiation Protection and Measurements (NCRP) has recently established a Task Group on Soil Contamination to describe and evaluate the migration pathways and modes of radiation exposure that can potentially arise due to radioactive contamination of soil. The purpose of this paper is to describe the scientific principles for evaluation of soil contamination which can be used as a basis for derivation of soil contamination limits for specific situations. This paper describes scenarios that can lead to soil contamination, important characteristics of soil contamination, the subsequent migration pathways and exposure modes, and the application of principles in the report in deriving soil contamination limits. The migration pathways and exposure modes discussed in this paper include: direct radiation exposure; and exhalation of gases

  10. Rumble surfaces

    CSIR Research Space (South Africa)

    National Institute for Transport and Road

    1977-01-01

    Full Text Available Rumble surfaces are intermittent short lengths of coarse-textured road surfacings on which vehicle tyres produce a rumbling sound. used in conjunction with appropriate roadsigns and markings, they can reduce accidents on rural roads by alerting...

  11. Effective task communication : the role of task information and the interpersonal teacher-student relationship.

    NARCIS (Netherlands)

    Broekkamp, H.; Dijk, van E.; Brekelmans, J.M.G.; Mainhard, T.; Brok, den P.J.

    2009-01-01

    Students who perceive assigned academic tasks as more clear perform better on these tasks. Moreover, it has been shown that "task clarity" (as experienced by students) varies across teachers. Apparently, some teachers are more effective than other teachers in communicating tasks. There is, however,

  12. Is Performance in Task-Cuing Experiments Mediated by Task Set Selection or Associative Compound Retrieval?

    Science.gov (United States)

    Forrest, Charlotte L. D.; Monsell, Stephen; McLaren, Ian P. L.

    2014-01-01

    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed,…

  13. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    Science.gov (United States)

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  14. The Effect of a Workload-Preview on Task-Prioritization and Task-Performance

    Science.gov (United States)

    Minotra, Dev

    2012-01-01

    With increased volume and sophistication of cyber attacks in recent years, maintaining situation awareness and effective task-prioritization strategy is critical to the task of cybersecurity analysts. However, high levels of mental-workload associated with the task of cybersecurity analyst's limits their ability to prioritize tasks.…

  15. Surface thermodynamics

    International Nuclear Information System (INIS)

    Garcia-Moliner, F.

    1975-01-01

    Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions

  16. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  17. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects. PMID:25904890

  18. On the importance of Task 1 and error performance measures in PRP dual-task studies.

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  19. The Applicability of Rhythm-Motor Tasks to a New Dual Task Paradigm for Older Adults

    Directory of Open Access Journals (Sweden)

    Soo Ji Kim

    2017-12-01

    Full Text Available Given the interplay between cognitive and motor functions during walking, cognitive demands required during gait have been investigated with regard to dual task performance. Along with the needs to understand how the type of concurrent task while walking affects gait performance, there are calls for diversified dual tasks that can be applied to older adults with varying levels of cognitive decline. Therefore, this study aimed to examine how rhythm-motor tasks affect dual task performance and gait control, compared to a traditional cognitive-motor task. Also, it examined whether rhythm-motor tasks are correlated with traditional cognitive-motor task performance and cognitive measures. Eighteen older adults without cognitive impairment participated in this study. Each participant was instructed to walk at self-paced tempo without performing a concurrent task (single walking task and walk while separately performing two types of concurrent tasks: rhythm-motor and cognitive-motor tasks. Rhythm-motor tasks included instrument playing (WalkIP, matching to rhythmic cueing (WalkRC, and instrument playing while matching to rhythmic cueing (WalkIP+RC. The cognitive-motor task involved counting forward by 3s (WalkCount.f3. In each condition, dual task costs (DTC, a measure for how dual tasks affect gait parameters, were measured in terms of walking speed and stride length. The ratio of stride length to walking speed, a measure for dynamic control of gait, was also examined. The results of this study demonstrated that the task type was found to significantly influence these measures. Rhythm-motor tasks were found to interfere with gait parameters to a lesser extent than the cognitive-motor task (WalkCount.f3. In terms of ratio measures, stride length remained at a similar level, walking speed greatly decreased in the WalkCount.f3 condition. Significant correlations between dual task-related measures during rhythm-motor and cognitive-motor tasks support the

  20. The task complexity experiment 2003/2004

    International Nuclear Information System (INIS)

    Laumann, Karin; Braarud, Per Oeivind; Svengren, Haakan

    2005-08-01

    The purpose of this experiment was to explore how additional tasks added to base case scenarios affected the operators' performance of the main tasks. These additional tasks were in different scenario variants intended to cause high time pressure, high information load, and high masking. The experiment was run in Halden Man-Machine Laboratory's BWR simulator. Seven crews participated, each for one week. There were three operators in each crew. Five main types of scenarios and 20 scenario variants were run. The data from the experiment were analysed by completion time for important actions and by in-depth qualitative analyses of the crews' communications. The results showed that high time pressure decreased some of the crews' performance in the scenarios. When a crew had problems in solving a task for which the time pressure was high, they had even more problems in solving other important tasks. High information load did not affect the operators' performance much and in general the crews were very good at selecting the most important tasks in the scenarios. The scenarios that included both high time pressure and high information load resulted in more reduced performance for the crews compared to the scenarios that only included high time pressure. The total amount of tasks to do and information load to attend to seemed to affect the crews' performance. To solve the scenarios with high time pressure well, it was important to have good communication and good allocation of tasks within the crew. Furthermore, the results showed that scenarios with an added complex, masked task created problems for some crews when solving a relatively simple main task. Overall, the results confirmed that complicating, but secondary tasks, that are not normally taken into account when modelling the primary tasks in a PRA scenario can adversely affect the performance of the main tasks modelled in the PRA scenario. (Author)

  1. Task 7: ADPAC User's Manual

    Science.gov (United States)

    Hall, E. J.; Topp, D. A.; Delaney, R. A.

    1996-01-01

    The overall objective of this study was to develop a 3-D numerical analysis for compressor casing treatment flowfields. The current version of the computer code resulting from this study is referred to as ADPAC (Advanced Ducted Propfan Analysis Codes-Version 7). This report is intended to serve as a computer program user's manual for the ADPAC code developed under Tasks 6 and 7 of the NASA Contract. The ADPAC program is based on a flexible multiple- block grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. An iterative implicit algorithm is available for rapid time-dependent flow calculations, and an advanced two equation turbulence model is incorporated to predict complex turbulent flows. The consolidated code generated during this study is capable of executing in either a serial or parallel computing mode from a single source code. Numerous examples are given in the form of test cases to demonstrate the utility of this approach for predicting the aerodynamics of modem turbomachinery configurations.

  2. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach

    2015-04-01

    Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  3. Task-focused modeling in automated agriculture

    Science.gov (United States)

    Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack

    1993-01-01

    Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

  4. Unnecessary work tasks and mental health

    DEFF Research Database (Denmark)

    Madsen, Ida E H; Tripathi, Manisha; Borritz, Marianne

    2014-01-01

    OBJECTIVES: According to the "stress-as-offense-to-self" perspective, work tasks that are considered unnecessary or unreasonable - so-called "illegitimate work tasks" - are likely to elicit stress-reactions. Previous studies, mostly cross-sectional, have shown that illegitimate tasks are associated...... with increased self-reported stress, cortisol, and counterproductive work behavior. In this article, we examine the prospective association between unnecessary work tasks, one type of illegitimate work tasks, and mental health among Danish human service workers. Further, we explore whether this association...... is modified by sex, age, occupational position, and baseline mental health status. METHODS: The data were obtained from self-administered questionnaires from 1351 Danish human service workers in three waves of data-collection during 1999-2005. We measured unnecessary work tasks by a single item, and assessed...

  5. Overview of job and task analysis

    International Nuclear Information System (INIS)

    Gertman, D.I.

    1984-01-01

    During the past few years the nuclear industry has become concerned with predicting human performance in nuclear power plants. One of the best means available at the present time to make sure that training, procedures, job performance aids and plant hardware match the capabilities and limitations of personnel is by performing a detailed analysis of the tasks required in each job position. The approved method for this type of analysis is referred to as job or task analysis. Job analysis is a broader type of analysis and is usually thought of in terms of establishing overall performance objectives, and in establishing a basis for position descriptions. Task analysis focuses on the building blocks of task performance, task elements, and places them within the context of specific performance requirements including time to perform, feedback required, special tools used, and required systems knowledge. The use of task analysis in the nuclear industry has included training validation, preliminary risk screening, and procedures development

  6. PDES Logical Layer Initiation Task.

    Science.gov (United States)

    1986-04-28

    surface. We have heard such expressions as "topology sits on tcp of geometry." We choose to avoid subordinating one to the other by bringing them together...a mapping from Discipline model to Global model. 38 A~A g d ip . t ~ P A1 / /oaefZ - - 6jOM#AL Mat&mft9 We have attempted to group basqd on the...FIGURE PHASE 2: Conceptualization and Integration. In this phase conceptual entities and relationships are discovered. An integrated conceptual modelO

  7. Predictive performance models and multiple task performance

    Science.gov (United States)

    Wickens, Christopher D.; Larish, Inge; Contorer, Aaron

    1989-01-01

    Five models that predict how performance of multiple tasks will interact in complex task scenarios are discussed. The models are shown in terms of the assumptions they make about human operator divided attention. The different assumptions about attention are then empirically validated in a multitask helicopter flight simulation. It is concluded from this simulation that the most important assumption relates to the coding of demand level of different component tasks.

  8. A new semantic vigilance task: vigilance decrement, workload, and sensitivity to dual-task costs.

    Science.gov (United States)

    Epling, Samantha L; Russell, Paul N; Helton, William S

    2016-01-01

    Cognitive resource theory is a common explanation for both the performance decline in vigilance tasks, known as the vigilance decrement, and the limited ability to perform multiple tasks simultaneously. The limited supply of cognitive resources may be utilized faster than they are replenished resulting in a performance decrement, or may need to be allocated among multiple tasks with some performance cost. Researchers have proposed both domain-specific, for example spatial versus verbal processing resources, and domain general cognitive resources. One challenge in testing the domain specificity of cognitive resources in vigilance is the current lack of difficult semantic vigilance tasks which reliably produce a decrement. In the present research, we investigated whether the vigilance decrement was found in a new abbreviated semantic discrimination vigilance task, and whether there was a performance decrement in said vigilance task when paired with a word recall task, as opposed to performed individually. As hypothesized, a vigilance decrement in the semantic vigilance task was found in both the single-task and dual-task conditions, along with reduced vigilance performance in the dual-task condition and reduced word recall in the dual-task condition. This is consistent with cognitive resource theory. The abbreviated semantic vigilance task will be a useful tool for researchers interested in determining the specificity of cognitive resources utilized in vigilance tasks.

  9. Walking modality, but not task difficulty, influences the control of dual-task walking.

    Science.gov (United States)

    Wrightson, J G; Smeeton, N J

    2017-10-01

    During dual-task gait, changes in the stride-to-stride variability of stride time (STV) are suggested to represent the allocation of cognitive control to walking [1]. However, contrasting effects have been reported for overground and treadmill walking, which may be due to differences in the relative difficulty of the dual task. Here we compared the effect of overground and treadmill dual-task walking on STV in 18 healthy adults. Participants walked overground and on a treadmill for 120s during single-task (walking only) and dual-task (walking whilst performing serial subtractions in sevens) conditions. Dual-task effects on STV, cognitive task (serial subtraction) performance and perceived task difficulty were compared between walking modalities. STV was increased during overground dual-task walking, but was unchanged during treadmill dual-task walking. There were no differences in cognitive task performance or perceived task difficulty. These results show that gait is controlled differently during overground and treadmill dual-task walking. However, these differences are not solely due to differences in task difficulty, and may instead represent modality dependent control strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Task oriented evaluation system for maintenance robots

    International Nuclear Information System (INIS)

    Asame, Hajime; Endo, Isao; Kotosaka, Shin-ya; Takata, Shozo; Hiraoka, Hiroyuki; Kohda, Takehisa; Matsumoto, Akihiro; Yamagishi, Kiichiro.

    1994-01-01

    The adaptability evaluation of maintenance robots to autonomous plants has been discussed. In this paper, a new concept of autonomous plant with maintenance robots are introduced, and a framework of autonomous maintenance system is proposed. Then, task-oriented evaluation of robot arms is discussed for evaluating their adaptability to maintenance tasks, and a new criterion called operability is proposed for adaptability evaluation. The task-oriented evaluation system is implemented and applied to structural design of robot arms. Using genetic algorithm, an optimal structure adaptable to a pump disassembly task is obtained. (author)

  11. Task-oriented maximally entangled states

    International Nuclear Information System (INIS)

    Agrawal, Pankaj; Pradhan, B

    2010-01-01

    We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

  12. Beads task vs. box task: The specificity of the jumping to conclusions bias.

    Science.gov (United States)

    Balzan, Ryan P; Ephraums, Rachel; Delfabbro, Paul; Andreou, Christina

    2017-09-01

    Previous research involving the probabilistic reasoning 'beads task' has consistently demonstrated a jumping-to-conclusions (JTC) bias, where individuals with delusions make decisions based on limited evidence. However, recent studies have suggested that miscomprehension may be confounding the beads task. The current study aimed to test the conventional beads task against a conceptually simpler probabilistic reasoning "box task" METHODS: One hundred non-clinical participants completed both the beads task and the box task, and the Peters et al. Delusions Inventory (PDI) to assess for delusion-proneness. The number of 'draws to decision' was assessed for both tasks. Additionally, the total amount of on-screen evidence was manipulated for the box task, and two new box task measures were assessed (i.e., 'proportion of evidence requested' and 'deviation from optimal solution'). Despite being conceptually similar, the two tasks did not correlate, and participants requested significantly less information on the beads task relative to the box task. High-delusion-prone participants did not demonstrate hastier decisions on either task; in fact, for box task, this group was observed to be significantly more conservative than low-delusion-prone group. Neither task was incentivized; results need replication with a clinical sample. Participants, and particularly those identified as high-delusion-prone, displayed a more conservative style of responding on the novel box task, relative to the beads task. The two tasks, whilst conceptually similar, appear to be tapping different cognitive processes. The implications of these results are discussed in relation to the JTC bias and the theoretical mechanisms thought to underlie it. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

    Science.gov (United States)

    Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

    2013-09-01

    Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

  14. Drug and alcohol task force

    Energy Technology Data Exchange (ETDEWEB)

    Gordey, T [ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Sunstrum, M [Enform, Calgary, AB (Canada)

    2006-07-01

    Worker absenteeism due to substance abuse costs the Alberta economy approximately $720 million a year. It is estimated that 20 per cent of all drivers in fatal crashes were using alcohol, and the use of cannabis and cocaine in Alberta has more than doubled over the last 15 years. In addition, 1 in 10 Alberta workers have reported using alcohol while at work and 4 per cent have reported using alcohol 4 hours prior to coming to work during the previous 12 months. In an effort to ensure appropriate health and safety for workers in the Canadian petroleum industry, 6 trade associations in the sector have joined together as the Enform Alcohol and Drug Initiative and are now working to develop a common approach to drug and alcohol guidelines and workplace rules. The task group will determine if existing policies and guidelines are sufficient to ensure a safe workplace and will consider standardizing the testing, application and rehabilitation of workers with respect to the use of drugs and alcohol. In the past, disciplinary actions have often been reversed because employers have not been consistent or did not follow established alcohol and drug policies or test to specific standards. Various work rules for inappropriate alcohol and drug use were reviewed, as well as education and communication strategies regarding policy content. Standards for testing criteria were discussed, as well as issues concerning duty-to-accommodate circumstances. An excerpt of concentration standards was presented. It was concluded that a matrix for companies to assess and determine safety sensitive positions is needed. refs., tabs., figs.

  15. Drug and alcohol task force

    International Nuclear Information System (INIS)

    Gordey, T.; Sunstrum, M.

    2006-01-01

    Worker absenteeism due to substance abuse costs the Alberta economy approximately $720 million a year. It is estimated that 20 per cent of all drivers in fatal crashes were using alcohol, and the use of cannabis and cocaine in Alberta has more than doubled over the last 15 years. In addition, 1 in 10 Alberta workers have reported using alcohol while at work and 4 per cent have reported using alcohol 4 hours prior to coming to work during the previous 12 months. In an effort to ensure appropriate health and safety for workers in the Canadian petroleum industry, 6 trade associations in the sector have joined together as the Enform Alcohol and Drug Initiative and are now working to develop a common approach to drug and alcohol guidelines and workplace rules. The task group will determine if existing policies and guidelines are sufficient to ensure a safe workplace and will consider standardizing the testing, application and rehabilitation of workers with respect to the use of drugs and alcohol. In the past, disciplinary actions have often been reversed because employers have not been consistent or did not follow established alcohol and drug policies or test to specific standards. Various work rules for inappropriate alcohol and drug use were reviewed, as well as education and communication strategies regarding policy content. Standards for testing criteria were discussed, as well as issues concerning duty-to-accommodate circumstances. An excerpt of concentration standards was presented. It was concluded that a matrix for companies to assess and determine safety sensitive positions is needed. refs., tabs., figs

  16. TASK 2: QUENCH ZONE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  17. The IEA Large Coil Task

    International Nuclear Information System (INIS)

    Beard, D.S.; Klose, W.; Shimamoto, S.; Vecsey, G.

    1988-01-01

    A multinational program of cooperative research, development, demonstrations, and exchanges of information on superconducting magnets for fusion was initiated in 1977 under an IEA agreement. The first major step in the development of TF magnets was called the Large Coil Task. Participants in LCT were the U.S. DOE, EURATOM, JAERI, and the Departement Federal de l'Interieur of Switzerland. The goals of LCT were to obtain experimental data, to demonstrate reliable operation of large superconducting coils, and to prove design principles and fabrication techniques being considered for the toroidal magnets of thermonuclear reactors. These goals were to be accomplished through coordinated but largely independent design, development, and construction of six test coils, followed by collaborative testing in a compact toroidal test array at fields of 8 T and higher. Under the terms of the IEA Agreement, the United States built and operated the test facility at Oak Ridge and provided three test coils. The other participants provided one coil each. Information on design and manufacturing and all test data were shared by all. The LCT team of each participant included a government laboratory and industrial partners or contractors. The last coil was completed in 1985, and the test assembly was completed in October of that year. Over the next 23 months, the six-coil array was cooled down and extensive testing was performed. Results were gratifying, as tests achieved design-point performance and well beyond. (Each coil reached a peak field of 9 T.) Experiments elucidated coil behavior, delineated limits of operability, and demonstrated coil safety. (orig./KP)

  18. Self-Efficacy, Task Complexity and Task Performance: Exploring Interactions in Two Versions of Vocabulary Learning Tasks

    Science.gov (United States)

    Wu, Xiaoli; Lowyck, Joost; Sercu, Lies; Elen, Jan

    2012-01-01

    The present study aimed for better understanding of the interactions between task complexity and students' self-efficacy beliefs and students' use of learning strategies, and finally their interacting effects on task performance. This investigation was carried out in the context of Chinese students learning English as a foreign language in a…

  19. Different Neuroplasticity for Task Targets and Distractors

    Science.gov (United States)

    Spingath, Elsie Y.; Kang, Hyun Sug; Plummer, Thane; Blake, David T.

    2011-01-01

    Adult learning-induced sensory cortex plasticity results in enhanced action potential rates in neurons that have the most relevant information for the task, or those that respond strongly to one sensory stimulus but weakly to its comparison stimulus. Current theories suggest this plasticity is caused when target stimulus evoked activity is enhanced by reward signals from neuromodulatory nuclei. Prior work has found evidence suggestive of nonselective enhancement of neural responses, and suppression of responses to task distractors, but the differences in these effects between detection and discrimination have not been directly tested. Using cortical implants, we defined physiological responses in macaque somatosensory cortex during serial, matched, detection and discrimination tasks. Nonselective increases in neural responsiveness were observed during detection learning. Suppression of responses to task distractors was observed during discrimination learning, and this suppression was specific to cortical locations that sampled responses to the task distractor before learning. Changes in receptive field size were measured as the area of skin that had a significant response to a constant magnitude stimulus, and these areal changes paralleled changes in responsiveness. From before detection learning until after discrimination learning, the enduring changes were selective suppression of cortical locations responsive to task distractors, and nonselective enhancement of responsiveness at cortical locations selective for target and control skin sites. A comparison of observations in prior studies with the observed plasticity effects suggests that the non-selective response enhancement and selective suppression suffice to explain known plasticity phenomena in simple spatial tasks. This work suggests that differential responsiveness to task targets and distractors in primary sensory cortex for a simple spatial detection and discrimination task arise from nonselective

  20. Different neuroplasticity for task targets and distractors.

    Directory of Open Access Journals (Sweden)

    Elsie Y Spingath

    2011-01-01

    Full Text Available Adult learning-induced sensory cortex plasticity results in enhanced action potential rates in neurons that have the most relevant information for the task, or those that respond strongly to one sensory stimulus but weakly to its comparison stimulus. Current theories suggest this plasticity is caused when target stimulus evoked activity is enhanced by reward signals from neuromodulatory nuclei. Prior work has found evidence suggestive of nonselective enhancement of neural responses, and suppression of responses to task distractors, but the differences in these effects between detection and discrimination have not been directly tested. Using cortical implants, we defined physiological responses in macaque somatosensory cortex during serial, matched, detection and discrimination tasks. Nonselective increases in neural responsiveness were observed during detection learning. Suppression of responses to task distractors was observed during discrimination learning, and this suppression was specific to cortical locations that sampled responses to the task distractor before learning. Changes in receptive field size were measured as the area of skin that had a significant response to a constant magnitude stimulus, and these areal changes paralleled changes in responsiveness. From before detection learning until after discrimination learning, the enduring changes were selective suppression of cortical locations responsive to task distractors, and nonselective enhancement of responsiveness at cortical locations selective for target and control skin sites. A comparison of observations in prior studies with the observed plasticity effects suggests that the non-selective response enhancement and selective suppression suffice to explain known plasticity phenomena in simple spatial tasks. This work suggests that differential responsiveness to task targets and distractors in primary sensory cortex for a simple spatial detection and discrimination task arise from

  1. 48 CFR 1852.216-80 - Task ordering procedure.

    Science.gov (United States)

    2010-10-01

    ... individual task order, accounting and appropriation data. (e) The Contractor shall provide acknowledgement of... conflict between the requirements of the task order and the Contractor's approved task plan, the task order...

  2. Dynamics of the central bottleneck: dual-task and task uncertainty.

    Directory of Open Access Journals (Sweden)

    Mariano Sigman

    2006-07-01

    Full Text Available Why is the human brain fundamentally limited when attempting to execute two tasks at the same time or in close succession? Two classical paradigms, psychological refractory period (PRP and task switching, have independently approached this issue, making significant advances in our understanding of the architecture of cognition. Yet, there is an apparent contradiction between the conclusions derived from these two paradigms. The PRP paradigm, on the one hand, suggests that the simultaneous execution of two tasks is limited solely by a passive structural bottleneck in which the tasks are executed on a first-come, first-served basis. The task-switching paradigm, on the other hand, argues that switching back and forth between task configurations must be actively controlled by a central executive system (the system controlling voluntary, planned, and flexible action. Here we have explicitly designed an experiment mixing the essential ingredients of both paradigms: task uncertainty and task simultaneity. In addition to a central bottleneck, we obtain evidence for active processes of task setting (planning of the appropriate sequence of actions and task disengaging (suppression of the plan set for the first task in order to proceed with the next one. Our results clarify the chronometric relations between these central components of dual-task processing, and in particular whether they operate serially or in parallel. On this basis, we propose a hierarchical model of cognitive architecture that provides a synthesis of task-switching and PRP paradigms.

  3. Task-set inertia and memory-consolidation bottleneck in dual tasks.

    Science.gov (United States)

    Koch, Iring; Rumiati, Raffaella I

    2006-11-01

    Three dual-task experiments examined the influence of processing a briefly presented visual object for deferred verbal report on performance in an unrelated auditory-manual reaction time (RT) task. RT was increased at short stimulus-onset asynchronies (SOAs) relative to long SOAs, showing that memory consolidation processes can produce a functional processing bottleneck in dual-task performance. In addition, the experiments manipulated the spatial compatibility of the orientation of the visual object and the side of the speeded manual response. This cross-task compatibility produced relative RT benefits only when the instruction for the visual task emphasized overlap at the level of response codes across the task sets (Experiment 1). However, once the effective task set was in place, it continued to produce cross-task compatibility effects even in single-task situations ("ignore" trials in Experiment 2) and when instructions for the visual task did not explicitly require spatial coding of object orientation (Experiment 3). Taken together, the data suggest a considerable degree of task-set inertia in dual-task performance, which is also reinforced by finding costs of switching task sequences (e.g., AC --> BC vs. BC --> BC) in Experiment 3.

  4. Surface mining

    Science.gov (United States)

    Robert Leopold; Bruce Rowland; Reed Stalder

    1979-01-01

    The surface mining process consists of four phases: (1) exploration; (2) development; (3) production; and (4) reclamation. A variety of surface mining methods has been developed, including strip mining, auger, area strip, open pit, dredging, and hydraulic. Sound planning and design techniques are essential to implement alternatives to meet the myriad of laws,...

  5. Superhydrophobic surfaces

    Science.gov (United States)

    Wang, Evelyn N; McCarthy, Matthew; Enright, Ryan; Culver, James N; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-03-24

    Surfaces having a hierarchical structure--having features of both microscale and nanoscale dimensions--can exhibit superhydrophobic properties and advantageous condensation and heat transfer properties. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.

  6. Surface characterization

    Science.gov (United States)

    Mandla A. Tshabalala

    2005-01-01

    Surface properties of wood play an important role when wood is used or processed into different commodities such as siding, joinery, textiles, paper, sorption media or wood composites. Thus, for example, the quality and durability of a wood coating are determined by the surface properties of the wood and the coating. The same is true for wood composites, as the...

  7. Compliant Task Execution and Learning for Safe Mixed-Initiative Human-Robot Operations

    Science.gov (United States)

    Dong, Shuonan; Conrad, Patrick R.; Shah, Julie A.; Williams, Brian C.; Mittman, David S.; Ingham, Michel D.; Verma, Vandana

    2011-01-01

    We introduce a novel task execution capability that enhances the ability of in-situ crew members to function independently from Earth by enabling safe and efficient interaction with automated systems. This task execution capability provides the ability to (1) map goal-directed commands from humans into safe, compliant, automated actions, (2) quickly and safely respond to human commands and actions during task execution, and (3) specify complex motions through teaching by demonstration. Our results are applicable to future surface robotic systems, and we have demonstrated these capabilities on JPL's All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) robot.

  8. Challenging experiences: gender differences in task choice

    NARCIS (Netherlands)

    de Pater, I.E.; van Vianen, A.E.M.; Fischer, A.H.; van Ginkel, W.P.

    2009-01-01

    Purpose - The purpose of this paper is to examine: gender differences in the choice to perform challenging tasks, gender differences in the actual performance of challenging tasks, and the impact of challenging experiences on supervisors' evaluations of individuals' potential for career advancement.

  9. Using ADA Tasks to Simulate Operating Equipment

    Science.gov (United States)

    DeAcetis, Louis A.; Schmidt, Oron; Krishen, Kumar

    1990-01-01

    A method of simulating equipment using ADA tasks is discussed. Individual units of equipment are coded as concurrently running tasks that monitor and respond to input signals. This technique has been used in a simulation of the space-to-ground Communications and Tracking subsystem of Space Station Freedom.

  10. Task based synthesis of serial manipulators

    Directory of Open Access Journals (Sweden)

    Sarosh Patel

    2015-05-01

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

  11. Headteachers' managerial behaviour and teachers' task ...

    African Journals Online (AJOL)

    The result of the study revealed that head teachers' decision-making strategy and head teachers' leadership style have significant influence on teachers' task performance in the sampled schools. And that head teachers' communication skills significantly relates to teachers' task performance in the area. Based on this result, ...

  12. Antiphospholipid Syndrome Clinical Research Task Force Report

    NARCIS (Netherlands)

    Erkan, D.; Derksen, R.; Levy, R.; Machin, S.; Ortel, T.; Pierangeli, S.; Roubey, R.; Lockshin, M.

    The Antiphospholipid Syndrome (APS) Clinical Research Task Force (CRTF) was one of six Task Forces developed by the 13(th) International Congress on Antiphospholipid Antibodies (aPL) organization committee with the purpose of: a) evaluating the limitations of APS clinical research and developing

  13. Workplace for analysis of task performance

    NARCIS (Netherlands)

    Bos, J; Mulder, LJM; van Ouwerkerk, RJ; Maarse, FJ; Akkerman, AE; Brand, AN; Mulder, LJM

    2003-01-01

    In current research on mental workload and task performance a large gap exists between laboratory based studies and research projects in real life working practice. Tasks conducted within a laboratory environment often lack a strong resemblance with real life working situations. This paper presents

  14. Contextual control over task-set retrieval.

    Science.gov (United States)

    Crump, Matthew J C; Logan, Gordon D

    2010-11-01

    Contextual cues signaling task likelihood or the likelihood of task repetition are known to modulate the size of switch costs. We follow up on the finding by Leboe, Wong, Crump, and Stobbe (2008) that location cues predictive of the proportion of switch or repeat trials modulate switch costs. Their design employed one cue per task, whereas our experiment employed two cues per task, which allowed separate assessment of modulations to the cue-repetition benefit, a measure of lower level cue-encoding processes, and to the task-alternation cost, a measure of higher level processes representing task-set information. We demonstrate that location information predictive of switch proportion modulates performance at the level of task-set representations. Furthermore, we demonstrate that contextual control occurs even when subjects are unaware of the associations between context and switch likelihood. We discuss the notion that contextual information provides rapid, unconscious control over the extent to which prior task-set representations are retrieved in the service of guiding online performance.

  15. Second Workshop on Supporting Complex Search Tasks

    NARCIS (Netherlands)

    Belkin, Nicholas J.; Bogers, Toine; Kamps, Jaap; Kelly, Diane; Koolen, Marijn; Yilmaz, Emine

    2017-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is

  16. Programming task packages: Peach exchange format

    NARCIS (Netherlands)

    Verhoeff, T.

    2008-01-01

    Programming education and contests have introduced software to help evaluation by executing submitted taskwork. We present the notion of a task package as a unit for collecting, storing, archiving, and exchanging all information concerning a programming task. We also describe a specific format for

  17. Limitations in dual-task performance

    NARCIS (Netherlands)

    Pannebakker, Merel Mathilde

    2009-01-01

    In this thesis, the effect of information-processing overload on working-memory dependent information processing was examined using dual-task paradigms. The experiments described strengthen the importance of a functional explanation for dual-task limitations. First, it showed evidence for a unified

  18. IEA HIA Task 37 - Hydrogen Safety

    DEFF Research Database (Denmark)

    Markert, Frank

    The work plan and objectives of this task are designed to support the acceleration of safe implementation of hydrogen infrastructure through coordinated international collaborations and hydrogen safety knowledge dissemination.......The work plan and objectives of this task are designed to support the acceleration of safe implementation of hydrogen infrastructure through coordinated international collaborations and hydrogen safety knowledge dissemination....

  19. Pleasantness of Creative Tasks and Creative Performance

    Science.gov (United States)

    Zenasni, Franck; Lubart, Todd

    2011-01-01

    To examine the impact of emotion on creative potential, experimental studies have typically focused on the impact of induced or spontaneous mood states on creative performance. In this report the relationship between the perceived pleasantness of tasks (using divergent thinking and story writing tasks) and creative performance was examined.…

  20. Industrial Occupations. Education for Employment Task Lists.

    Science.gov (United States)

    Lake County Area Vocational Center, Grayslake, IL.

    The duties and tasks found in these task lists form the basis of instructional content for secondary, postsecondary, and adult occupational training programs for industrial occupations. The industrial occupations are divided into eight clusters. The clusters and occupations are: construction cluster (bricklayer, carpenter, building maintenance…

  1. Multi-task Vector Field Learning.

    Science.gov (United States)

    Lin, Binbin; Yang, Sen; Zhang, Chiyuan; Ye, Jieping; He, Xiaofei

    2012-01-01

    Multi-task learning (MTL) aims to improve generalization performance by learning multiple related tasks simultaneously and identifying the shared information among tasks. Most of existing MTL methods focus on learning linear models under the supervised setting. We propose a novel semi-supervised and nonlinear approach for MTL using vector fields. A vector field is a smooth mapping from the manifold to the tangent spaces which can be viewed as a directional derivative of functions on the manifold. We argue that vector fields provide a natural way to exploit the geometric structure of data as well as the shared differential structure of tasks, both of which are crucial for semi-supervised multi-task learning. In this paper, we develop multi-task vector field learning (MTVFL) which learns the predictor functions and the vector fields simultaneously. MTVFL has the following key properties. (1) The vector fields MTVFL learns are close to the gradient fields of the predictor functions. (2) Within each task, the vector field is required to be as parallel as possible which is expected to span a low dimensional subspace. (3) The vector fields from all tasks share a low dimensional subspace. We formalize our idea in a regularization framework and also provide a convex relaxation method to solve the original non-convex problem. The experimental results on synthetic and real data demonstrate the effectiveness of our proposed approach.

  2. Efficient task assignment in spatial crowdsourcing with worker and task privacy protection

    KAUST Repository

    Liu, An; Wang, Weiqi; Shang, Shuo; Li, Qing; Zhang, Xiangliang

    2017-01-01

    Spatial crowdsourcing (SC) outsources tasks to a set of workers who are required to physically move to specified locations and accomplish tasks. Recently, it is emerging as a promising tool for emergency management, as it enables efficient and cost

  3. Planning and task management in Parkinson's disease: differential emphasis in dual-task performance.

    Science.gov (United States)

    Bialystok, Ellen; Craik, Fergus I M; Stefurak, Taresa

    2008-03-01

    Seventeen patients diagnosed with Parkinson's disease completed a complex computer-based task that involved planning and management while also performing an attention-demanding secondary task. The tasks were performed concurrently, but it was necessary to switch from one to the other. Performance was compared to a group of healthy age-matched control participants and a group of young participants. Parkinson's patients performed better than the age-matched controls on almost all measures and as well as the young controls in many cases. However, the Parkinson's patients achieved this by paying relatively less attention to the secondary task and focusing attention more on the primary task. Thus, Parkinson's patients can apparently improve their performance on some aspects of a multidimensional task by simplifying task demands. This benefit may occur as a consequence of their inflexible exaggerated attention to some aspects of a complex task to the relative neglect of other aspects.

  4. Task complexity and task, goal, and reward interdependence in group performance management : A prescriptive model

    NARCIS (Netherlands)

    van Vijfeijken, H.; Kleingeld, A.; van Tuijl, H.; Algera, J.A.; Thierry, Hk.

    2002-01-01

    A prescriptive model on how to design effective combinations of goal setting and contingent rewards for group performance management is presented. The model incorporates the constructs task complexity, task interdependence, goal interdependence, and reward interdependence and specifies optimal fit

  5. Task complexity and task, goal, and reward interdependence in group performance : a prescriptive model

    NARCIS (Netherlands)

    Vijfeijken, van H.T.G.A.; Kleingeld, P.A.M.; Tuijl, van H.F.J.M.; Algera, J.A.; Thierry, H.

    2002-01-01

    A prescriptive model on how to design effective combinations of goal setting and contingent rewards for group performance management is presented. The model incorporates the constructs task complexity, task interdependence, goal interdependence, and reward interdependence and specifies optimal fit

  6. Robot Task Commander with Extensible Programming Environment

    Science.gov (United States)

    Hart, Stephen W (Inventor); Yamokoski, John D. (Inventor); Wightman, Brian J (Inventor); Dinh, Duy Paul (Inventor); Gooding, Dustin R (Inventor)

    2014-01-01

    A system for developing distributed robot application-level software includes a robot having an associated control module which controls motion of the robot in response to a commanded task, and a robot task commander (RTC) in networked communication with the control module over a network transport layer (NTL). The RTC includes a script engine(s) and a GUI, with a processor and a centralized library of library blocks constructed from an interpretive computer programming code and having input and output connections. The GUI provides access to a Visual Programming Language (VPL) environment and a text editor. In executing a method, the VPL is opened, a task for the robot is built from the code library blocks, and data is assigned to input and output connections identifying input and output data for each block. A task sequence(s) is sent to the control module(s) over the NTL to command execution of the task.

  7. PBF task and training requirements analysis

    International Nuclear Information System (INIS)

    Blackman, H.S.; Gertman, D.I.; Petersen, R.J.

    1983-05-01

    Task analyses were used to assist in identifying improvements needed in the training curriculum for selected positions at the Power Burst Facility (PBF). Four positions were examined: Experiment Power Reactor Operator, Experiment (EPRO-Ex); Experiment Power Reactor Operator, Plant (EPRO-P); Experiment Power Reactor Operator, Console (EPRO-Co), and Shift Supervisor (SS). A complete position task listing and core of tasks defined in terms of (a) level of difficulty to perform, (b) severity of consequence if performed improperly, and (c) associated error probability were identified by each position. The systems, academic, and administrative knowledge needed by job incumbents to perform each task was noted. Strategies for teaching the knowledge associated with these tasks are presented

  8. Task mapping for non-contiguous allocations.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew.; Feer, Stefan P.; Rhodes, Zachary D.

    2013-02-01

    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  9. Error Sonification of a Complex Motor Task

    Directory of Open Access Journals (Sweden)

    Riener Robert

    2011-12-01

    Full Text Available Visual information is mainly used to master complex motor tasks. Thus, additional information providing augmented feedback should be displayed in other modalities than vision, e.g. hearing. The present work evaluated the potential of error sonification to enhance learning of a rowing-type motor task. In contrast to a control group receiving self-controlled terminal feedback, the experimental group could not significantly reduce spatial errors. Thus, motor learning was not enhanced by error sonification, although during the training the participant could benefit from it. It seems that the motor task was too slow, resulting in immediate corrections of the movement rather than in an internal representation of the general characteristics of the motor task. Therefore, further studies should elaborate the impact of error sonification when general characteristics of the motor tasks are already known.

  10. Trait Mindfulness and Cognitive Task Performance

    Directory of Open Access Journals (Sweden)

    Emalee J. W. Quickel

    2014-11-01

    Full Text Available Mindfulness meditation (MM training has been shown to have positive effects on working memory and focused attention tasks. Clarifying the construct of mindfulness is important so that mindfulness can be studied effectively in individual differences and cognition research. The current study tested whether trait mindfulness alone explains any of the variability on task performance. Five commonly used mindfulness scales, as well as six standardized and experimental attention and working memory tasks were administered to 164 participants with no meditation experience. Confirmatory factor analysis found that the common variance denoted by measures of trait mindfulness is unrelated to the common variance among tasks requiring focused attention. These results indicate that mindfulness scales may not be capturing the attentional aspects of mindfulness. Individuals who score high on mindfulness scales do not perform better on focused attention tasks than those who score lower on mindfulness scales. These results have implications for defining and operationalizing mindfulness.

  11. Control and Interference in Task Switching--A Review

    Science.gov (United States)

    Kiesel, Andrea; Steinhauser, Marco; Wendt, Mike; Falkenstein, Michael; Jost, Kerstin; Philipp, Andrea M.; Koch, Iring

    2010-01-01

    The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching…

  12. Task difficulty, risk, effort and comfort in a simulated driving task--Implications for Risk Allostasis Theory.

    Science.gov (United States)

    Lewis-Evans, Ben; Rothengatter, Talib

    2009-09-01

    Risk Allostasis Theory states that drivers seek to maintain a feeling of risk within a preferred range [Fuller, R., 2008. What drives the driver? Surface tensions and hidden consensus. In: Keynote at the 4th International Conference on Traffic and Transport Psychology, Washington, DC, August 31-September 4, 2008]. Risk Allostasis Theory is the latest version of Task-Difficulty Homeostasis theory, and is in part based on the findings of experiments where participants were asked to rate the task difficulty, feeling of risk and chance of collision of scenes shown in digitally altered video clips [Fuller, R., McHugh, C., Pender, S., 2008b. Task difficulty and risk in the determination of driver behaviour. Revue européenne de psychologie appliqée 58, 13-21]. The focus of the current research was to expand upon the previous video based experiments using a driving simulator. This allowed participants to be in control of the vehicle rather than acting as passive observers, as well as providing additional speed cues. The results support previous findings that ratings of task difficulty and feeling of risk are related, and that they are also highly related to ratings of effort and moderately related to ratings of comfort and habit. However, the linearly increasing trend for task difficulty and feeling of risk described by the previous research was not observed: instead the findings of this experiment support a threshold effect where ratings of risk (feeling of and chance of loss of control/collision), difficulty, effort, and comfort go through a period of stability and only start to increase once a certain threshold has been crossed. It is within the period of stability where subjective experience of risk and difficulty is low, or absent, that drivers generally prefer to operate.

  13. Prospective memory in young and older adults: the effects of task importance and ongoing task load.

    Science.gov (United States)

    Smith, Rebekah E; Hunt, R Reed

    2014-01-01

    Remembering to perform an action in the future, called prospective memory, often shows age-related differences in favor of young adults when tested in the laboratory. Recently Smith, Horn, and Bayen (2012; Aging, Neuropsychology, and Cognition, 19, 495) embedded a PM task in an ongoing color-matching task and manipulated the difficulty of the ongoing task by varying the number of colors on each trial of the task. Smith et al. found that age-related differences in PM performance (lower PM performance for older adults relative to young adults) persisted even when older adults could perform the ongoing task as well or better than the young adults. The current study investigates a possible explanation for the pattern of results reported by Smith et al. by including a manipulation of task emphasis: for half of the participants the prospective memory task was emphasize, while for the other half the ongoing color-matching task was emphasized. Older adults performed a 4-color version of the ongoing color-matching task, while young adults completed either the 4-color or a more difficult 6-color version of the ongoing task. Older adults failed to perform as well as the young adults on the prospective memory task regardless of task emphasis, even when older adults were performing as well or better than the young adults on the ongoing color-matching task. The current results indicate that the lack of an effect of ongoing task load on prospective memory task performance is not due to a perception that one or the other task is more important than the other.

  14. Dividing attention between tasks : Testing whether explicit payoff functions elicit optimal dual-task performance

    NARCIS (Netherlands)

    Farmer, George D.; Janssen, C.P.|info:eu-repo/dai/nl/412781654; Nguyen, Anh T; Brumby, Duncan P.

    2018-01-01

    We test people's ability to optimize performance across two concurrent tasks. Participants performed a number entry task while controlling a randomly moving cursor with a joystick. Participants received explicit feedback on their performance on these tasks in the form of a single combined score.

  15. Selecting Learning Tasks: Effects of Adaptation and Shared Control on Learning Efficiency and Task Involvement

    Science.gov (United States)

    Corbalan, Gemma; Kester, Liesbeth; van Merrienboer, Jeroen J. G.

    2008-01-01

    Complex skill acquisition by performing authentic learning tasks is constrained by limited working memory capacity [Baddeley, A. D. (1992). Working memory. "Science, 255", 556-559]. To prevent cognitive overload, task difficulty and support of each newly selected learning task can be adapted to the learner's competence level and perceived task…

  16. The Effect of Focus on Form and Task Complexity on L2 Learners' Oral Task Performance

    Science.gov (United States)

    Salimi, Asghar

    2015-01-01

    Second Language learners' oral task performance has been one of interesting and research generating areas of investigations in the field of second language acquisition specially, task-based language teaching and learning. The main purpose of the present study is to investigate the effect of focus on form and task complexity on L2 learners' oral…

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

    Science.gov (United States)

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

    2012-01-01

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

  18. Task Repetition Effects on L1 Use in EFL Child Task-Based Interaction

    Science.gov (United States)

    Azkarai, Agurtzane; García Mayo, María del Pilar

    2017-01-01

    Research has shown that tasks provide second language (L2) learners with many opportunities to learn the L2. Task repetition has been claimed to benefit L2 learning since familiarity with procedure and/or content gives learners the chance to focus on more specific aspects of language. Most research on task repetition has focused on adult…

  19. Task 7c: Worm tank

    International Nuclear Information System (INIS)

    1999-01-01

    Worm tank has a unique shape. In the seismic design of a worm tank, it is desirable to clear the behavior of the worm tank under the seismic loading. We assumed that there are two phenomena in the seismic behavior of the worm tank same as the behavior of the cylindrical and rectangular tanks. One is a sloshing behavior of the water and another is the dynamic response of the worm tank. In this study, we investigate the dynamic characteristics of the worm tank during the strong earthquakes. We conducted the vibration tests to clarify the seismic behaviors of the worm tanks and obtained the valuable data to verify the analytical method. It was found that the natural frequency can be calculated using the eigenvalue formula of the cylindrical and rectangular tanks. Lower modes of the worm tank are identical with that of the rectangular tank. We can estimate the surface behavior and the impact mode using the data of the rectangular tank. (author)

  20. Developmental changes in using verbal self-cueing in task-switching situations: the impact of task practice and task-sequencing demands

    Science.gov (United States)

    Kray, Jutta; Gaspard, Hanna; Karbach, Julia; Blaye, Agnès

    2013-01-01

    In this study we examined whether developmental changes in using verbal self-cueing for task-goal maintenance are dependent on the amount of task practice and task-sequencing demands. To measure task-goal maintenance we applied a switching paradigm in which children either performed only task A or B in single-task blocks or switched between them on every second trial in mixed-task blocks. Task-goal maintenance was determined by comparing the performance between both blocks (mixing costs). The influence of verbal self-cueing was measured by instructing children to either name the next task aloud or not to verbalize during task preparation. Task-sequencing demands were varied between groups whereas one group received spatial task cues to support keeping track of the task sequence, while the other group did not. We also varied by the amount of prior practice in task switching while one group of participants practiced task switching first, before performing the task naming in addition, and the other group did it vice versa. Results of our study investigating younger (8–10 years) and older children (11–13 years) revealed no age differences in beneficial effects of verbal self-cueing. In line with previous findings, children showed reduced mixing costs under task-naming instructions and under conditions of low task-sequence demands (with the presence of spatial task cues). Our results also indicated that these benefits were only obtained for those groups of children that first received practice in task switching alone with no additional verbalization instruction. These findings suggest that internal task-cueing strategies can be efficiently used in children but only if they received prior practice in the underlying task so that demands on keeping and coordinating various instructions are reduced. Moreover, children benefitted from spatial task cues for better task-goal maintenance only if no verbal task-cueing strategy was introduced first. PMID:24381566

  1. Cooperative endocytosis of the endosomal SNARE protein syntaxin-8 and the potassium channel TASK-1

    Science.gov (United States)

    Renigunta, Vijay; Fischer, Thomas; Zuzarte, Marylou; Kling, Stefan; Zou, Xinle; Siebert, Kai; Limberg, Maren M.; Rinné, Susanne; Decher, Niels; Schlichthörl, Günter; Daut, Jürgen

    2014-01-01

    The endosomal SNARE protein syntaxin-8 interacts with the acid-sensitive potassium channel TASK-1. The functional relevance of this interaction was studied by heterologous expression of these proteins (and mutants thereof) in Xenopus oocytes and in mammalian cell lines. Coexpression of syntaxin-8 caused a fourfold reduction in TASK-1 current, a corresponding reduction in the expression of TASK-1 at the cell surface, and a marked increase in the rate of endocytosis of the channel. TASK-1 and syntaxin-8 colocalized in the early endosomal compartment, as indicated by the endosomal markers 2xFYVE and rab5. The stimulatory effect of the SNARE protein on the endocytosis of the channel was abolished when both an endocytosis signal in TASK-1 and an endocytosis signal in syntaxin-8 were mutated. A syntaxin-8 mutant that cannot assemble with other SNARE proteins had virtually the same effect as wild-type syntaxin-8. Total internal reflection fluorescence microscopy showed formation and endocytosis of vesicles containing fluorescence-tagged clathrin, TASK-1, and/or syntaxin-8. Our results suggest that the unassembled form of syntaxin-8 and the potassium channel TASK-1 are internalized via clathrin-mediated endocytosis in a cooperative manner. This implies that syntaxin-8 regulates the endocytosis of TASK-1. Our study supports the idea that endosomal SNARE proteins can have functions unrelated to membrane fusion. PMID:24743596

  2. Implicit and Explicit Knowledge Both Improve Dual Task Performance in a Continuous Pursuit Tracking Task.

    Science.gov (United States)

    Ewolds, Harald E; Bröker, Laura; de Oliveira, Rita F; Raab, Markus; Künzell, Stefan

    2017-01-01

    The goal of this study was to investigate the effect of predictability on dual-task performance in a continuous tracking task. Participants practiced either informed (explicit group) or uninformed (implicit group) about a repeated segment in the curves they had to track. In Experiment 1 participants practices the tracking task only, dual-task performance was assessed after by combining the tracking task with an auditory reaction time task. Results showed both groups learned equally well and tracking performance on a predictable segment in the dual-task condition was better than on random segments. However, reaction times did not benefit from a predictable tracking segment. To investigate the effect of learning under dual-task situation participants in Experiment 2 practiced the tracking task while simultaneously performing the auditory reaction time task. No learning of the repeated segment could be demonstrated for either group during the training blocks, in contrast to the test-block and retention test, where participants performed better on the repeated segment in both dual-task and single-task conditions. Only the explicit group improved from test-block to retention test. As in Experiment 1, reaction times while tracking a predictable segment were no better than reaction times while tracking a random segment. We concluded that predictability has a positive effect only on the predictable task itself possibly because of a task-shielding mechanism. For dual-task training there seems to be an initial negative effect of explicit instructions, possibly because of fatigue, but the advantage of explicit instructions was demonstrated in a retention test. This might be due to the explicit memory system informing or aiding the implicit memory system.

  3. Convex surfaces

    CERN Document Server

    Busemann, Herbert

    2008-01-01

    This exploration of convex surfaces focuses on extrinsic geometry and applications of the Brunn-Minkowski theory. It also examines intrinsic geometry and the realization of intrinsic metrics. 1958 edition.

  4. Surface boxplots

    KAUST Repository

    Genton, Marc G.

    2014-01-22

    In this paper, we introduce a surface boxplot as a tool for visualization and exploratory analysis of samples of images. First, we use the notion of volume depth to order the images viewed as surfaces. In particular, we define the median image. We use an exact and fast algorithm for the ranking of the images. This allows us to detect potential outlying images that often contain interesting features not present in most of the images. Second, we build a graphical tool to visualize the surface boxplot and its various characteristics. A graph and histogram of the volume depth values allow us to identify images of interest. The code is available in the supporting information of this paper. We apply our surface boxplot to a sample of brain images and to a sample of climate model outputs.

  5. Surface boxplots

    KAUST Repository

    Genton, Marc G.; Johnson, Christopher; Potter, Kristin; Stenchikov, Georgiy L.; Sun, Ying

    2014-01-01

    In this paper, we introduce a surface boxplot as a tool for visualization and exploratory analysis of samples of images. First, we use the notion of volume depth to order the images viewed as surfaces. In particular, we define the median image. We use an exact and fast algorithm for the ranking of the images. This allows us to detect potential outlying images that often contain interesting features not present in most of the images. Second, we build a graphical tool to visualize the surface boxplot and its various characteristics. A graph and histogram of the volume depth values allow us to identify images of interest. The code is available in the supporting information of this paper. We apply our surface boxplot to a sample of brain images and to a sample of climate model outputs.

  6. Surface channeling

    International Nuclear Information System (INIS)

    Sizmann, R.; Varelas, C.

    1976-01-01

    There is experimental evidence that swift light ions incident at small angles towards single crystalline surfaces can lose an appreciable fraction of their kinetic energy during reflection. It is shown that these projectiles penetrate into the bulk surface region of the crystal. They can travel as channeled particles along long paths through the solid (surface channeling). The angular distribution and the depth history of the re-emerged projectiles are investigated by computer simulations. A considerable fraction of the penetrating projectiles re-emerges from the crystal with constant transverse energy if the angle of incidence is smaller than the critical angle for axial channeling. Analytical formulae are derived based on a diffusion model for surface channeling. A comparison with experimental data exhibits the relevance of the analytical solutions. (Auth.)

  7. Survival Processing and the Stroop Task

    Directory of Open Access Journals (Sweden)

    Stephanie A. Kazanas

    2015-11-01

    Full Text Available This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an important evolutionary adaptation and not specific to humans as is the case with word recall. Our results indicate that survival processing, with its accompanying survival-relevance rating task, remains the best mnemonic strategy for word memory. However, our results also indicate that presenting the survival passage does not motivate better color-naming performance than color-naming alone. In addition, survival processing led to a larger amount of Stroop interference, though not significantly larger than the other conditions. Together, these findings suggest that considering one’s survival when performing memory and attention-based tasks does not enhance cognitive performance generally, although greater allocation of attentional resources to color-incongruent concrete objects could be considered adaptive. These findings support the notion that engaging in deeper processing via survival-relevance ratings may preserve these words across a variety of experimental manipulations.

  8. Computing Visible-Surface Representations,

    Science.gov (United States)

    1985-03-01

    Terzopoulos N00014-75-C-0643 9. PERFORMING ORGANIZATION NAME AMC ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK Artificial Inteligence Laboratory AREA A...Massachusetts Institute of lechnolog,. Support lbr the laboratory’s Artificial Intelligence research is provided in part by the Advanced Rtccarcl Proj...dynamically maintaining visible surface representations. Whether the intention is to model human vision or to design competent artificial vision systems

  9. Martian surface

    International Nuclear Information System (INIS)

    Carr, M.H.

    1987-01-01

    The surface of Mars is characterized on the basis of reformatted Viking remote-sensing data, summarizing results published during the period 1983-1986. Topics examined include impact craters, ridges and faults, volcanic studies (modeling of surface effects on volcanic activity, description and interpretation of volcanic features, and calculations on lava-ice interactions), the role of liquid water on Mars, evidence for abundant ground ice at high latitudes, water-cycle modeling, and the composition and dynamics of Martian dust

  10. Surface decontamination

    International Nuclear Information System (INIS)

    Silva, S. da; Teixeira, M.V.

    1986-06-01

    The general methods of surface decontamination used in laboratory and others nuclear installations areas, as well as the procedures for handling radioactive materials and surfaces of work are presented. Some methods for decontamination of body external parts are mentioned. The medical supervision and assistance are required for internal or external contamination involving or not lesion in persons. From this medical radiation protection decontamination procedures are determined. (M.C.K.) [pt

  11. Overview of the ID, EPI and REL tasks of BioNLP Shared Task 2011

    Directory of Open Access Journals (Sweden)

    Pyysalo Sampo

    2012-06-01

    Full Text Available Abstract We present the preparation, resources, results and analysis of three tasks of the BioNLP Shared Task 2011: the main tasks on Infectious Diseases (ID and Epigenetics and Post-translational Modifications (EPI, and the supporting task on Entity Relations (REL. The two main tasks represent extensions of the event extraction model introduced in the BioNLP Shared Task 2009 (ST'09 to two new areas of biomedical scientific literature, each motivated by the needs of specific biocuration tasks. The ID task concerns the molecular mechanisms of infection, virulence and resistance, focusing in particular on the functions of a class of signaling systems that are ubiquitous in bacteria. The EPI task is dedicated to the extraction of statements regarding chemical modifications of DNA and proteins, with particular emphasis on changes relating to the epigenetic control of gene expression. By contrast to these two application-oriented main tasks, the REL task seeks to support extraction in general by separating challenges relating to part-of relations into a subproblem that can be addressed by independent systems. Seven groups participated in each of the two main tasks and four groups in the supporting task. The participating systems indicated advances in the capability of event extraction methods and demonstrated generalization in many aspects: from abstracts to full texts, from previously considered subdomains to new ones, and from the ST'09 extraction targets to other entities and events. The highest performance achieved in the supporting task REL, 58% F-score, is broadly comparable with levels reported for other relation extraction tasks. For the ID task, the highest-performing system achieved 56% F-score, comparable to the state-of-the-art performance at the established ST'09 task. In the EPI task, the best result was 53% F-score for the full set of extraction targets and 69% F-score for a reduced set of core extraction targets, approaching a level

  12. A Reverse Stroop Task with Mouse Tracking

    Science.gov (United States)

    Yamamoto, Naohide; Incera, Sara; McLennan, Conor T.

    2016-01-01

    In a reverse Stroop task, observers respond to the meaning of a color word irrespective of the color in which the word is printed—for example, the word red may be printed in the congruent color (red), an incongruent color (e.g., blue), or a neutral color (e.g., white). Although reading of color words in this task is often thought to be neither facilitated by congruent print colors nor interfered with incongruent print colors, this interference has been detected by using a response method that does not give any bias in favor of processing of word meanings or processing of print colors. On the other hand, evidence for the presence of facilitation in this task has been scarce, even though this facilitation is theoretically possible. By modifying the task such that participants respond to a stimulus color word by pointing to a corresponding response word on a computer screen with a mouse, the present study investigated the possibility that not only interference but also facilitation would take place in a reverse Stroop task. Importantly, in this study, participants’ responses were dynamically tracked by recording the entire trajectories of the mouse. Arguably, this method provided richer information about participants’ performance than traditional measures such as reaction time and accuracy, allowing for more detailed (and thus potentially more sensitive) investigation of facilitation and interference in the reverse Stroop task. These trajectories showed that the mouse’s approach toward correct response words was significantly delayed by incongruent print colors but not affected by congruent print colors, demonstrating that only interference, not facilitation, was present in the current task. Implications of these findings are discussed within a theoretical framework in which the strength of association between a task and its response method plays a critical role in determining how word meanings and print colors interact in reverse Stroop tasks. PMID:27199881

  13. Surface phonons

    CERN Document Server

    Wette, Frederik

    1991-01-01

    In recent years substantial progress has been made in the detection of surface phonons owing to considerable improvements in inelastic rare gas scattering tech­ niques and electron energy loss spectroscopy. With these methods it has become possible to measure surface vibrations in a wide energy range for all wave vectors in the two-dimensional Brillouin zone and thus to deduce the complete surface phonon dispersion curves. Inelastic atomic beam scattering and electron energy loss spectroscopy have started to play a role in the study of surface phonons similar to the one played by inelastic neutron scattering in the investigation of bulk phonons in the last thirty years. Detailed comparison between experimen­ tal results and theoretical studies of inelastic surface scattering and of surface phonons has now become feasible. It is therefore possible to test and to improve the details of interaction models which have been worked out theoretically in the last few decades. At this point we felt that a concise, co...

  14. Convolutional neural networks and face recognition task

    Science.gov (United States)

    Sochenkova, A.; Sochenkov, I.; Makovetskii, A.; Vokhmintsev, A.; Melnikov, A.

    2017-09-01

    Computer vision tasks are remaining very important for the last couple of years. One of the most complicated problems in computer vision is face recognition that could be used in security systems to provide safety and to identify person among the others. There is a variety of different approaches to solve this task, but there is still no universal solution that would give adequate results in some cases. Current paper presents following approach. Firstly, we extract an area containing face, then we use Canny edge detector. On the next stage we use convolutional neural networks (CNN) to finally solve face recognition and person identification task.

  15. Task performance in astronomical adaptive optics

    Science.gov (United States)

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

    2006-06-01

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

  16. Analysis of Human Communication during Assembly Tasks.

    Science.gov (United States)

    1986-06-01

    AD-A7l 43 ANALYSIS OF HUMAN COMMUNICATION DURING ASSEMBLY TASKS in1(U) CRNEGIE-MELLO UNIY PITTSBURGH PA ROBOTICS INST UNCLSSIIEDK S BARBER ET AL...ao I Dur~~~~IngAbcbyTs; 7c .S:in i lSAo .0. Analysis of Human Communication During Assembly Tasks K. Suzanne Barber and Gerald J. Agin CMU-RI-TR-86-1...TYPE or REPORT & PE-Rioo CevCZaz Analysis of Human Communication During Assembly Inlterim Tasks I . PERFORMING 00RG. REPORT NUMBER 1. £UT~oOR~e) IL

  17. Computerized management of plant intervention tasks

    International Nuclear Information System (INIS)

    Remacle, J.; Quoidbach, G.

    1993-01-01

    The concept of 'computerized management' of plant intervention tasks was developed by TRACTEBEL in 1983 for the Belgian power plants of ELECTRABEL. The main objective of the 'Computerized Management of Plant Intervention Tasks' is to help the staff of a nuclear or a conventional power plant in planning, organizing, and carrying out any (preventive or corrective) maintenance task. It consists of a group of interconnected functional modules acting on a unique and homogeneous data base. A short description of 3 modules is given, i.e., the 'User' Module, the 'Equipment' Module and the 'Periodic Procedure' Module. (Z.S.)

  18. Final Report on ITER Task Agreement 81-08

    Energy Technology Data Exchange (ETDEWEB)

    Richard L. Moore

    2008-03-01

    As part of an ITER Implementing Task Agreement (ITA) between the ITER US Participant Team (PT) and the ITER International Team (IT), the INL Fusion Safety Program was tasked to provide the ITER IT with upgrades to the fusion version of the MELCOR 1.8.5 code including a beryllium dust oxidation model. The purpose of this model is to allow the ITER IT to investigate hydrogen production from beryllium dust layers on hot surfaces inside the ITER vacuum vessel (VV) during in-vessel loss-of-cooling accidents (LOCAs). Also included in the ITER ITA was a task to construct a RELAP5/ATHENA model of the ITER divertor cooling loop to model the draining of the loop during a large ex-vessel pipe break followed by an in-vessel divertor break and compare the results to a simular MELCOR model developed by the ITER IT. This report, which is the final report for this agreement, documents the completion of the work scope under this ITER TA, designated as TA 81-08.

  19. Unique sensor fusion system for coordinate-measuring machine tasks

    Science.gov (United States)

    Nashman, Marilyn; Yoshimi, Billibon; Hong, Tsai Hong; Rippey, William G.; Herman, Martin

    1997-09-01

    This paper describes a real-time hierarchical system that fuses data from vision and touch sensors to improve the performance of a coordinate measuring machine (CMM) used for dimensional inspection tasks. The system consists of sensory processing, world modeling, and task decomposition modules. It uses the strengths of each sensor -- the precision of the CMM scales and the analog touch probe and the global information provided by the low resolution camera -- to improve the speed and flexibility of the inspection task. In the experiment described, the vision module performs all computations in image coordinate space. The part's boundaries are extracted during an initialization process and then the probe's position is continuously updated as it scans and measures the part surface. The system fuses the estimated probe velocity and distance to the part boundary in image coordinates with the estimated velocity and probe position provided by the CMM controller. The fused information provides feedback to the monitor controller as it guides the touch probe to scan the part. We also discuss integrating information from the vision system and the probe to autonomously collect data for 2-D to 3-D calibration, and work to register computer aided design (CAD) models with images of parts in the workplace.

  20. Sex differences in task distribution and task exposures among Danish house painters:

    DEFF Research Database (Denmark)

    Heilskov-Hansen, Thomas; Svendsen, Susanne Wulff; Thomsen, Jane Frølund

    2014-01-01

    OBJECTIVES: Sex differences in occupational biomechanical exposures may be part of the explanation why musculoskeletal complaints and disorders tend to be more common among women than among men. We aimed to determine possible sex differences in task distribution and task-specific postures...... correction were used to evaluate sex differences. RESULTS: Statistically significant (psex 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...... 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...

  1. The task of control digital image compression

    OpenAIRE

    TASHMANOV E.B.; МАМАTOV М.S.

    2014-01-01

    In this paper we consider the relationship of control tasks and image compression losses. The main idea of this approach is to allocate structural lines simplified image and further compress the selected data

  2. Autonomous Task Primitives for Complex Manipulation Operations

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this research effort is to enable robots to autonomously perform the complex manipulation tasks that are necessary to maintain a spacecraft. Robots, like...

  3. Workshift and Antihistamine Effects on Task Performance

    National Research Council Canada - National Science Library

    Gilliland, Kirby

    1997-01-01

    Sixteen male subjects, well trained on a battery of cognitive performance assessment tasks, participated in a study to Investigate the effects on human operator performance of work shift (Day Shift vs. Mid shift...

  4. An ergonomic task analysis of spinal anaesthesia.

    LENUS (Irish Health Repository)

    Ajmal, Muhammad

    2009-12-01

    Ergonomics is the study of physical interaction between humans and their working environment. The objective of this study was to characterize the performance of spinal anaesthesia in an acute hospital setting, applying ergonomic task analysis.

  5. Developing communicative competence through thinking tasks

    DEFF Research Database (Denmark)

    Maslo, Elina

    Developing communicative competence through thinking tasks - Experimenting with Thinking Approach in Danish as Second Language ClassroomSession on Innovations in the classroom, a presentation. Abstract for the conference Creativity & Thinking Skills in Learning, teaching & Management. Riga 19......-20 September 2014 Elina Maslo, Aarhus University, Department of Education, elma@edu.au.dk Summary: The goal of this presentation is to present some of the experiences with thinking tasks in the Danish language classroom, conducted in the Nordplus Nordic Language Project “Problem solving tasks for learning...... of Danish as second and foreign language in transformative learning spaces”. Two teachers have developed and tried out some thinking tasks in their classrooms, with the aim to foster the development of students´ communicative competence. The learning processes from two classrooms will be analysed...

  6. Automatic intersection map generation task 10 report.

    Science.gov (United States)

    2016-02-29

    This report describes the work conducted in Task 10 of the V2I Safety Applications Development Project. The work was performed by the University of Michigan Transportation Research Institute (UMTRI) under contract to the Crash Avoidance Metrics Partn...

  7. The Multinational Logistics Joint Task Force (MLJTF)

    National Research Council Canada - National Science Library

    Higginbotham, Matthew T

    2007-01-01

    In this monograph, by analyzing the UN, NATO and the US Army's evolving Modular Logistics Doctrine, the author integrates the key areas from each doctrine into a multinational logistics joint task force (MLJTF) organization...

  8. Phonological similarity in working memory span tasks.

    Science.gov (United States)

    Chow, Michael; Macnamara, Brooke N; Conway, Andrew R A

    2016-08-01

    In a series of four experiments, we explored what conditions are sufficient to produce a phonological similarity facilitation effect in working memory span tasks. By using the same set of memoranda, but differing the secondary-task requirements across experiments, we showed that a phonological similarity facilitation effect is dependent upon the semantic relationship between the memoranda and the secondary-task stimuli, and is robust to changes in the representation, ordering, and pool size of the secondary-task stimuli. These findings are consistent with interference accounts of memory (Brown, Neath, & Chater, Psychological Review, 114, 539-576, 2007; Oberauer, Lewandowsky, Farrell, Jarrold, & Greaves, Psychonomic Bulletin & Review, 19, 779-819, 2012), whereby rhyming stimuli provide a form of categorical similarity that allows distractors to be excluded from retrieval at recall.

  9. A Task-driven Grammar Refactoring Algorithm

    Directory of Open Access Journals (Sweden)

    Ivan Halupka

    2012-01-01

    Full Text Available This paper presents our proposal and the implementation of an algorithm for automated refactoring of context-free grammars. Rather than operating under some domain-specific task, in our approach refactoring is perfomed on the basis of a refactoring task defined by its user. The algorithm and the corresponding refactoring system are called mARTINICA. mARTINICA is able to refactor grammars of arbitrary size and structural complexity. However, the computation time needed to perform a refactoring task with the desired outcome is highly dependent on the size of the grammar. Until now, we have successfully performed refactoring tasks on small and medium-size grammars of Pascal-like languages and parts of the Algol-60 programming language grammar. This paper also briefly introduces the reader to processes occurring in grammar refactoring, a method for describing desired properties that a refactored grammar should fulfill, and there is a discussion of the overall significance of grammar refactoring.

  10. Quantifying tasks and roles in insect societies

    African Journals Online (AJOL)

    1991-05-15

    May 15, 1991 ... ergonomic selection, and was associated with the evolution of increasing behavioural ... The sequence in which tasks are perfonned by workers, .... space, providing a pictorial representation of the association between the ...

  11. Surface migration in sorption processes

    International Nuclear Information System (INIS)

    Rasmuson, A.; Neretnieks, J.

    1983-03-01

    Diffusion rates of sorbing chemical species in granites and clays are in several experiments within the KBS study, higher than can be explained by pore diffusion only. One possible additional transport mechanism is transport of of sorbed molecules/ions along the intrapore surfaces. As a first step a literature investigation on on solid surfaces has been conducted. A lot of experimental evidence of the mobility of the sorbed molecules has been gathered through the years, particulary for metal surfaces and chemical engineering systems. For clays however, there are only a few articles, and for granites none. Two types of surface migration models have been proposed in the litterature: i) Surface flow as a result of a gradient in spreading pressure. ii) Surface diffusion as a result of a gradient in concentration. The surface flow model has only been applied to gaseous systems. However, it should be equally applicable to liquid systems. The models i) and ii) are conceptually very different. However, the resulting expressions for surface flux are complicated and it will not be an easy task to distinguish between them. There seem to be three ways of discriminating between the transport mechanisms: a) Temperature dependence. b) Concentration dependence. c) Order of magnitude. (Forf)

  12. SemEval-2016 task 10

    DEFF Research Database (Denmark)

    Schneider, Nathan; Hovy, Dirk; Johannsen, Anders Trærup

    2016-01-01

    This task combines the labeling of multiword expressions and supersenses (coarse-grained classes) in an explicit, yet broad-coverage paradigm for lexical semantics. Nine systems participated; the best scored 57.7% F1 in a multi-domain evaluation setting, indicating that the task remains largely...... unresolved. An error analysis reveals that a large number of instances in the data set are either hard cases, which no systems get right, or easy cases, which all systems correctly solve....

  13. Limitations in dual-task performance

    OpenAIRE

    Pannebakker, Merel Mathilde

    2009-01-01

    In this thesis, the effect of information-processing overload on working-memory dependent information processing was examined using dual-task paradigms. The experiments described strengthen the importance of a functional explanation for dual-task limitations. First, it showed evidence for a unified coding medium (as put forward in the theory of event coding; Hommel, Müsseler, Aschersleben, & Prinz, 2001) in which features, operations and responses are available and can influence each other. A...

  14. Objective threshold for distinguishing complicated tasks

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Kyun; Jung, Won Dea [KAERI, Daejeon (Korea, Republic of)

    2014-08-15

    Estimating the likelihood of human error in a reliable manner is really important for enhancing the safety of a large process control system such as Nuclear Power Plants (NPPs). In this regard, from the point of view of Probabilistic Safety Assessment (PSA), various kinds of Human Reliability Analysis (HRA) methods have been used for several decades in order to systematically evaluate the effect of human error on the safety of NPPs. However, one of the recurrence issues is to determine the level of an important Performance Shaping Factor (PSF) by using a clear and objective manner with respect to the context of a given task. Unfortunately, there is no such criterion for a certain PSF such as the complexity of a task. For this reason, in this study, an objective criterion that is helpful for identifying a complicated task is suggested based on the Task Complexity (TACOM) measure. To this end, subjective difficulty scores rated by high speed train drivers are collected. After that, subjective difficulty scores are compared with the associated TACOM scores being quantified based on tasks to be conducted by high speed train drivers. As a result, it is expected that high speed train drivers feel a significant difficulty when they are faced with tasks of which the TACOM scores are greater than 4.2. Since TACOM measure is a kind of general tool to quantify the complexity of tasks to be done by human operators, it is promising to conclude that this value can be regarded as a common threshold representing what a complicated task is.

  15. An Architecture for Robot Assemblt Task Planning

    DEFF Research Database (Denmark)

    Sun, Hongyan

    1999-01-01

    This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution.......This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution....

  16. Task-Specific Training and Job Design

    OpenAIRE

    Felipe Balmaceda

    2006-01-01

    This paper provides a simple theoretical framework based on a new type of human capital introduced by Gibbons and Waldman (2004), called task-specific training, to understand job design. Mainly, in the presence of task-specific training, promotions might result ex-post in the underutilization of human capital and thus firms at the time of designing jobs should attempt to diversify this risk.

  17. Default mode network connectivity during task execution.

    Science.gov (United States)

    Vatansever, D; Menon, D K; Manktelow, A E; Sahakian, B J; Stamatakis, E A

    2015-11-15

    Initially described as task-induced deactivations during goal-directed paradigms of high attentional load, the unresolved functionality of default mode regions has long been assumed to interfere with task performance. However, recent evidence suggests a potential default mode network involvement in fulfilling cognitive demands. We tested this hypothesis in a finger opposition paradigm with task and fixation periods which we compared with an independent resting state scan using functional magnetic resonance imaging and a comprehensive analysis pipeline including activation, functional connectivity, behavioural and graph theoretical assessments. The results indicate task specific changes in the default mode network topography. Behaviourally, we show that increased connectivity of the posterior cingulate cortex with the left superior frontal gyrus predicts faster reaction times. Moreover, interactive and dynamic reconfiguration of the default mode network regions' functional connections illustrates their involvement with the task at hand with higher-level global parallel processing power, yet preserved small-world architecture in comparison with rest. These findings demonstrate that the default mode network does not disengage during this paradigm, but instead may be involved in task relevant processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. An FMRI-compatible Symbol Search task.

    Science.gov (United States)

    Liebel, Spencer W; Clark, Uraina S; Xu, Xiaomeng; Riskin-Jones, Hannah H; Hawkshead, Brittany E; Schwarz, Nicolette F; Labbe, Donald; Jerskey, Beth A; Sweet, Lawrence H

    2015-03-01

    Our objective was to determine whether a Symbol Search paradigm developed for functional magnetic resonance imaging (FMRI) is a reliable and valid measure of cognitive processing speed (CPS) in healthy older adults. As all older adults are expected to experience cognitive declines due to aging, and CPS is one of the domains most affected by age, establishing a reliable and valid measure of CPS that can be administered inside an MR scanner may prove invaluable in future clinical and research settings. We evaluated the reliability and construct validity of a newly developed FMRI Symbol Search task by comparing participants' performance in and outside of the scanner and to the widely used and standardized Symbol Search subtest of the Wechsler Adult Intelligence Scale (WAIS). A brief battery of neuropsychological measures was also administered to assess the convergent and discriminant validity of the FMRI Symbol Search task. The FMRI Symbol Search task demonstrated high test-retest reliability when compared to performance on the same task administered out of the scanner (r=.791; pSymbol Search (r=.717; pSymbol Search task were also observed. The FMRI Symbol Search task is a reliable and valid measure of CPS in healthy older adults and exhibits expected sensitivity to the effects of age on CPS performance.

  19. Reverse control for humanoid robot task recognition.

    Science.gov (United States)

    Hak, Sovannara; Mansard, Nicolas; Stasse, Olivier; Laumond, Jean Paul

    2012-12-01

    Efficient methods to perform motion recognition have been developed using statistical tools. Those methods rely on primitive learning in a suitable space, for example, the latent space of the joint angle and/or adequate task spaces. Learned primitives are often sequential: A motion is segmented according to the time axis. When working with a humanoid robot, a motion can be decomposed into parallel subtasks. For example, in a waiter scenario, the robot has to keep some plates horizontal with one of its arms while placing a plate on the table with its free hand. Recognition can thus not be limited to one task per consecutive segment of time. The method presented in this paper takes advantage of the knowledge of what tasks the robot is able to do and how the motion is generated from this set of known controllers, to perform a reverse engineering of an observed motion. This analysis is intended to recognize parallel tasks that have been used to generate a motion. The method relies on the task-function formalism and the projection operation into the null space of a task to decouple the controllers. The approach is successfully applied on a real robot to disambiguate motion in different scenarios where two motions look similar but have different purposes.

  20. Real-time scheduling of software tasks

    International Nuclear Information System (INIS)

    Hoff, L.T.

    1995-01-01

    When designing real-time systems, it is often desirable to schedule execution of software tasks based on the occurrence of events. The events may be clock ticks, interrupts from a hardware device, or software signals from other software tasks. If the nature of the events, is well understood, this scheduling is normally a static part of the system design. If the nature of the events is not completely understood, or is expected to change over time, it may be necessary to provide a mechanism for adjusting the scheduling of the software tasks. RHIC front-end computers (FECs) provide such a mechanism. The goals in designing this mechanism were to be as independent as possible of the underlying operating system, to allow for future expansion of the mechanism to handle new types of events, and to allow easy configuration. Some considerations which steered the design were programming paradigm (object oriented vs. procedural), programming language, and whether events are merely interesting moments in time, or whether they intrinsically have data associated with them. The design also needed to address performance and robustness tradeoffs involving shared task contexts, task priorities, and use of interrupt service routine (ISR) contexts vs. task contexts. This paper will explore these considerations and tradeoffs

  1. Task-Driven Comparison of Topic Models.

    Science.gov (United States)

    Alexander, Eric; Gleicher, Michael

    2016-01-01

    Topic modeling, a method of statistically extracting thematic content from a large collection of texts, is used for a wide variety of tasks within text analysis. Though there are a growing number of tools and techniques for exploring single models, comparisons between models are generally reduced to a small set of numerical metrics. These metrics may or may not reflect a model's performance on the analyst's intended task, and can therefore be insufficient to diagnose what causes differences between models. In this paper, we explore task-centric topic model comparison, considering how we can both provide detail for a more nuanced understanding of differences and address the wealth of tasks for which topic models are used. We derive comparison tasks from single-model uses of topic models, which predominantly fall into the categories of understanding topics, understanding similarity, and understanding change. Finally, we provide several visualization techniques that facilitate these tasks, including buddy plots, which combine color and position encodings to allow analysts to readily view changes in document similarity.

  2. Mostly surfaces

    CERN Document Server

    Schwartz, Richard Evan

    2011-01-01

    This book presents a number of topics related to surfaces, such as Euclidean, spherical and hyperbolic geometry, the fundamental group, universal covering surfaces, Riemannian manifolds, the Gauss-Bonnet Theorem, and the Riemann mapping theorem. The main idea is to get to some interesting mathematics without too much formality. The book also includes some material only tangentially related to surfaces, such as the Cauchy Rigidity Theorem, the Dehn Dissection Theorem, and the Banach-Tarski Theorem. The goal of the book is to present a tapestry of ideas from various areas of mathematics in a clear and rigorous yet informal and friendly way. Prerequisites include undergraduate courses in real analysis and in linear algebra, and some knowledge of complex analysis.

  3. Surface rights

    Directory of Open Access Journals (Sweden)

    Regina Célia Corrêa Landim

    2009-06-01

    Full Text Available In many cities of Brazil, social inequality is illustrated by violence, poverty, and unemployment located next to luxurious residential towers and armored passenger cars. In the face of this situation, the National Movement of Urban Reform encouraged the inclusion of the social function of property in Brazil's new constitution of 1988. Surface rights represent an urbanistic instrument in the city statute that is best aligned to the constitutional principles and urban policies. The current article compares two laws that govern the principle of surface rights and provides a brief history of the evolution of the state based on illuminism and the consequent change in paradigm affecting individual rights, including property and civil rights, and their interpretation under the Constitution. The article concludes by suggesting the use of land surface rights in a joint operation, matching the ownership of the property with urban planning policies and social interest.

  4. When predictions take control: The effect of task predictions on task switching performance

    Directory of Open Access Journals (Sweden)

    Wout eDuthoo

    2012-08-01

    Full Text Available In this paper, we aimed to investigate the role of self-generated predictions in the flexible control of behaviour. Therefore, we ran a task switching experiment in which participants were asked to try to predict the upcoming task in three conditions varying in switch rate (30%, 50% and 70%. Irrespective of their predictions, the colour of the target indicated which task participants had to perform. In line with previous studies (Mayr, 2006; Monsell & Mizon, 2006, the switch cost was attenuated as the switch rate increased. Importantly, a clear task repetition bias was found in all conditions, yet the task repetition prediction rate dropped from 78% over 66% to 49% with increasing switch probability in the three conditions. Irrespective of condition, the switch cost was strongly reduced in expectation of a task alternation compared to the cost of an unexpected task alternation following repetition predictions. Hence, our data suggest that the reduction in the switch cost with increasing switch probability is caused by a diminished expectancy for the task to repeat. Taken together, this paper highlights the importance of predictions in the flexible control of behaviour, and suggests a crucial role for task repetition expectancy in the context-sensitive adjusting of task switching performance.

  5. Strategic Adaptation to Task Characteristics, Incentives, and Individual Differences in Dual-Tasking.

    Directory of Open Access Journals (Sweden)

    Christian P Janssen

    Full Text Available We investigate how good people are at multitasking by comparing behavior to a prediction of the optimal strategy for dividing attention between two concurrent tasks. In our experiment, 24 participants had to interleave entering digits on a keyboard with controlling a randomly moving cursor with a joystick. The difficulty of the tracking task was systematically varied as a within-subjects factor. Participants were also exposed to different explicit reward functions that varied the relative importance of the tracking task relative to the typing task (between-subjects. Results demonstrate that these changes in task characteristics and monetary incentives, together with individual differences in typing ability, influenced how participants choose to interleave tasks. This change in strategy then affected their performance on each task. A computational cognitive model was used to predict performance for a wide set of alternative strategies for how participants might have possibly interleaved tasks. This allowed for predictions of optimal performance to be derived, given the constraints placed on performance by the task and cognition. A comparison of human behavior with the predicted optimal strategy shows that participants behaved near optimally. Our findings have implications for the design and evaluation of technology for multitasking situations, as consideration should be given to the characteristics of the task, but also to how different users might use technology depending on their individual characteristics and their priorities.

  6. Increased cognitive control after task conflict? Investigating the N-3 effect in task switching.

    Science.gov (United States)

    Schuch, Stefanie; Grange, James A

    2018-05-25

    Task inhibition is considered to facilitate switching to a new task and is assumed to decay slowly over time. Hence, more persisting inhibition needs to be overcome when returning to a task after one intermediary trial (ABA task sequence) than when returning after two or more intermediary trials (CBA task sequence). Schuch and Grange (J Exp Psychol Learn Mem Cogn 41:760-767, 2015) put forward the hypothesis that there is higher task conflict in ABA than CBA sequences, leading to increased cognitive control in the subsequent trial. They provided evidence that performance is better in trials following ABA than following CBA task sequences. Here, this effect of the previous task sequence ("N-3 effect") is further investigated by varying the cue-stimulus interval (CSI), allowing for short (100 ms) or long (900 ms) preparation time for the upcoming task. If increased cognitive control after ABA involves a better preparation for the upcoming task, the N-3 effect should be larger with long than short CSI. The results clearly show that this is not the case. In Experiment 1, the N-3 effect was smaller with long than short CSI; in Experiment 2, the N-3 effect was not affected by CSI. Diffusion model analysis confirmed previous results in the literature (regarding the effect of CSI and of the ABA-CBA difference); however, the N-3 effect was not unequivocally associated with any of the diffusion model parameters. In exploratory analysis, we also tested the alternative hypothesis that the N-3 effect involves more effective task shielding, which would be reflected in reduced congruency effects in trials following ABA, relative to trials following CBA; congruency effects did not differ between these conditions. Taken together, we can rule out two potential explanations of the N-3 effect: Neither is this effect due to enhanced task preparation, nor to more effective task shielding.

  7. Space Archaeology: Attribute, Object, Task and Method

    Science.gov (United States)

    Wang, Xinyuan; Guo, Huadong; Luo, Lei; Liu, Chuansheng

    2017-04-01

    Archaeology takes the material remains of human activity as the research object, and uses those fragmentary remains to reconstruct the humanistic and natural environment in different historical periods. Space Archaeology is a new branch of the Archaeology. Its study object is the humanistic-natural complex including the remains of human activities and living environments on the earth surface. The research method, space information technologies applied to this complex, is an innovative process concerning archaeological information acquisition, interpretation and reconstruction, and to achieve the 3-D dynamic reconstruction of cultural heritages by constructing the digital cultural-heritage sphere. Space archaeology's attribute is highly interdisciplinary linking several areas of natural and social and humanities. Its task is to reveal the history, characteristics, and patterns of human activities in the past, as well as to understand the evolutionary processes guiding the relationship between human and their environment. This paper summarizes six important aspects of space archaeology and five crucial recommendations for the establishment and development of this new discipline. The six important aspects are: (1) technologies and methods for non-destructive detection of archaeological sites; (2) space technologies for the protection and monitoring of cultural heritages; (3) digital environmental reconstruction of archaeological sites; (4) spatial data storage and data mining of cultural heritages; (5) virtual archaeology, digital reproduction and public information and presentation system; and (6) the construction of scientific platform of digital cultural-heritage sphere. The five key recommendations for establishing the discipline of Space Archaeology are: (1) encouraging the full integration of the strengths of both archaeology and museology with space technology to promote the development of space technologies' application for cultural heritages; (2) a new

  8. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Directory of Open Access Journals (Sweden)

    Bettina eGathmann

    2015-02-01

    Full Text Available Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring - an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task. This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST and the newly developed Balanced Switching Task (BST, measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task.

  9. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Science.gov (United States)

    Gathmann, Bettina; Schiebener, Johannes; Wolf, Oliver T.; Brand, Matthias

    2015-01-01

    Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring—an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task). This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST) and the newly developed Balanced Switching Task (BST), measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task. PMID:25741308

  10. Task conflict in the Stroop task: When Stroop interference decreases as Stroop facilitation increases in a low task conflict context

    Directory of Open Access Journals (Sweden)

    Benjamin Andrew Parris

    2014-10-01

    Full Text Available In the present study participants completed two blocks of the Stroop task, one in which the Response-Stimulus Interval (RSI was 3500ms and one in which RSI was 200ms. It was expected that, in line with previous research, the shorter RSI would induce a low Task Conflict context by increasing focus on the colour identification goal in the Stroop task. Based on previous research showing the role of Task Conflict in the presence or absence Stroop facilitation, this was expected to lead to the novel finding of an increase in facilitation and simultaneous decrease in interference. Such a finding would be problematic for models of Stroop effects that predict these indices of performance should be affected in tandem. A crossover interaction is reported supporting these predictions. As predicted, the shorter RSI resulted in incongruent and congruent trial RTs decreasing relative to a static neutral baseline condition; hence interference decreased as facilitation increased. An explanatory model (expanding on the work of Goldfarb, Henik and colleagues is presented that: 1 Shows how under certain conditions the predictions from single mechanism models hold true (i.e. when Task conflict is held constant; 2 Shows how it is possible that interference can be affected by an experimental manipulation that leaves facilitation apparently untouched and; 3 Predicts that facilitation cannot be independently affected by an experimental manipulation.

  11. Search and Hyperlinking Task at MediaEval 2012

    NARCIS (Netherlands)

    Eskevich, Maria; Jones, Gareth J.F.; Chen, Shu; Aly, Robin; Ordelman, Roeland J.F.; Larson, Martha

    2012-01-01

    The Search and Hyperlinking Task was one of the Brave New Tasks at MediaEval 2012. The Task consisted of two sub- tasks which focused on search and linking in retrieval from a collection of semi-professional video content. These tasks followed up on research carried out within the MediaEval 2011

  12. Attack surfaces

    DEFF Research Database (Denmark)

    Gruschka, Nils; Jensen, Meiko

    2010-01-01

    The new paradigm of cloud computing poses severe security risks to its adopters. In order to cope with these risks, appropriate taxonomies and classification criteria for attacks on cloud computing are required. In this work-in-progress paper we present one such taxonomy based on the notion...... of attack surfaces of the cloud computing scenario participants....

  13. Heimdall System for MSSS Sensor Tasking

    Science.gov (United States)

    Herz, A.; Jones, B.; Herz, E.; George, D.; Axelrad, P.; Gehly, S.

    In Norse Mythology, Heimdall uses his foreknowledge and keen eyesight to keep watch for disaster from his home near the Rainbow Bridge. Orbit Logic and the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado (CU) have developed the Heimdall System to schedule observations of known and uncharacterized objects and search for new objects from the Maui Space Surveillance Site. Heimdall addresses the current need for automated and optimized SSA sensor tasking driven by factors associated with improved space object catalog maintenance. Orbit Logic and CU developed an initial baseline prototype SSA sensor tasking capability for select sensors at the Maui Space Surveillance Site (MSSS) using STK and STK Scheduler, and then added a new Track Prioritization Component for FiSST-inspired computations for predicted Information Gain and Probability of Detection, and a new SSA-specific Figure-of-Merit (FOM) for optimized SSA sensor tasking. While the baseline prototype addresses automation and some of the multi-sensor tasking optimization, the SSA-improved prototype addresses all of the key elements required for improved tasking leading to enhanced object catalog maintenance. The Heimdall proof-of-concept was demonstrated for MSSS SSA sensor tasking for a 24 hour period to attempt observations of all operational satellites in the unclassified NORAD catalog, observe a small set of high priority GEO targets every 30 minutes, make a sky survey of the GEO belt region accessible to MSSS sensors, and observe particular GEO regions that have a high probability of finding new objects with any excess sensor time. This Heimdall prototype software paves the way for further R&D that will integrate this technology into the MSSS systems for operational scheduling, improve the software's scalability, and further tune and enhance schedule optimization. The Heimdall software for SSA sensor tasking provides greatly improved performance over manual tasking, improved

  14. Mood states determine the degree of task shielding in dual-task performance.

    Science.gov (United States)

    Zwosta, Katharina; Hommel, Bernhard; Goschke, Thomas; Fischer, Rico

    2013-01-01

    Current models of multitasking assume that dual-task performance and the degree of multitasking are affected by cognitive control strategies. In particular, cognitive control is assumed to regulate the amount of shielding of the prioritised task from crosstalk from the secondary task. We investigated whether and how task shielding is influenced by mood states. Participants were exposed to two short film clips, one inducing high and one inducing low arousal, of either negative or positive content. Negative mood led to stronger shielding of the prioritised task (i.e., less crosstalk) than positive mood, irrespective of arousal. These findings support the assumption that emotional states determine the parameters of cognitive control and play an important role in regulating dual-task performance.

  15. Secondary task for full flight simulation incorporating tasks that commonly cause pilot error: Time estimation

    Science.gov (United States)

    Rosch, E.

    1975-01-01

    The task of time estimation, an activity occasionally performed by pilots during actual flight, was investigated with the objective of providing human factors investigators with an unobtrusive and minimally loading additional task that is sensitive to differences in flying conditions and flight instrumentation associated with the main task of piloting an aircraft simulator. Previous research indicated that the duration and consistency of time estimates is associated with the cognitive, perceptual, and motor loads imposed by concurrent simple tasks. The relationships between the length and variability of time estimates and concurrent task variables under a more complex situation involving simulated flight were clarified. The wrap-around effect with respect to baseline duration, a consequence of mode switching at intermediate levels of concurrent task distraction, should contribute substantially to estimate variability and have a complex effect on the shape of the resulting distribution of estimates.

  16. Estimating the operator's performance time of emergency procedural tasks based on a task complexity measure

    International Nuclear Information System (INIS)

    Jung, Won Dae; Park, Jink Yun

    2012-01-01

    It is important to understand the amount of time required to execute an emergency procedural task in a high-stress situation for managing human performance under emergencies in a nuclear power plant. However, the time to execute an emergency procedural task is highly dependent upon expert judgment due to the lack of actual data. This paper proposes an analytical method to estimate the operator's performance time (OPT) of a procedural task, which is based on a measure of the task complexity (TACOM). The proposed method for estimating an OPT is an equation that uses the TACOM as a variable, and the OPT of a procedural task can be calculated if its relevant TACOM score is available. The validity of the proposed equation is demonstrated by comparing the estimated OPTs with the observed OPTs for emergency procedural tasks in a steam generator tube rupture scenario.

  17. Allocating time to future tasks: the effect of task segmentation on planning fallacy bias.

    Science.gov (United States)

    Forsyth, Darryl K; Burt, Christopher D B

    2008-06-01

    The scheduling component of the time management process was used as a "paradigm" to investigate the allocation of time to future tasks. In three experiments, we compared task time allocation for a single task with the summed time allocations given for each subtask that made up the single task. In all three, we found that allocated time for a single task was significantly smaller than the summed time allocated to the individual subtasks. We refer to this as the segmentation effect. In Experiment 3, we asked participants to give estimates by placing a mark on a time line, and found that giving time allocations in the form of rounded close approximations probably does not account for the segmentation effect. We discuss the results in relation to the basic processes used to allocate time to future tasks and the means by which planning fallacy bias might be reduced.

  18. Heart Rate Response During Mission-Critical Tasks After Space Flight

    Science.gov (United States)

    Arzeno, Natalia M.; Lee, S. M. C.; Stenger, M. B.; Lawrence, E. L.; Platts, S. H.; Bloomberg, J. J.

    2010-01-01

    Adaptation to microgravity could impair crewmembers? ability to perform required tasks upon entry into a gravity environment, such as return to Earth, or during extraterrestrial exploration. Historically, data have been collected in a controlled testing environment, but it is unclear whether these physiologic measures result in changes in functional performance. NASA?s Functional Task Test (FTT) aims to investigate whether adaptation to microgravity increases physiologic stress and impairs performance during mission-critical tasks. PURPOSE: To determine whether the well-accepted postflight tachycardia observed during standard laboratory tests also would be observed during simulations of mission-critical tasks during and after recovery from short-duration spaceflight. METHODS: Five astronauts participated in the FTT 30 days before launch, on landing day, and 1, 6, and 30 days after landing. Mean heart rate (HR) was measured during 5 simulations of mission-critical tasks: rising from (1) a chair or (2) recumbent seated position followed by walking through an obstacle course (egress from a space vehicle), (3) translating graduated masses from one location to another (geological sample collection), (4) walking on a treadmill at 6.4 km/h (ambulation on planetary surface), and (5) climbing 40 steps on a passive treadmill ladder (ingress to lander). For tasks 1, 2, 3, and 5, astronauts were encouraged to complete the task as quickly as possible. Time to complete tasks and mean HR during each task were analyzed using repeated measures ANOVA and ANCOVA respectively, in which task duration was a covariate. RESULTS: Landing day HR was higher (P < 0.05) than preflight during the upright seat egress (7%+/-3), treadmill walk (13%+/-3) and ladder climb (10%+/-4), and HR remained elevated during the treadmill walk 1 day after landing. During tasks in which HR was not elevated on landing day, task duration was significantly greater on landing day (recumbent seat egress: 25

  19. Task representation in individual and joint settings

    Directory of Open Access Journals (Sweden)

    Wolfgang ePrinz

    2015-05-01

    Full Text Available This paper outlines a framework for task representation and discusses applications to interference tasks in individual and joint settings. The framework is derived from the Theory of Event Coding. This theory regards task sets as transient assemblies of event codes in which stimulus and response codes interact and shape each other in particular ways. On the one hand, stimulus and response codes compete with each other within their respective subsets (horizontal interactions. On the other hand, stimulus and response code cooperate with each other (vertical interactions. Code interactions instantiating competition and cooperation apply to two time scales: on-line performance (i.e., doing the task and off-line implementation (i.e., setting the task. Interference arises when stimulus and response codes overlap in features that are irrelevant for stimulus identification, but relevant for response selection. To resolve this dilemma, the feature profiles of event codes may become restructured in various ways. The framework is applied to three kinds of interference paradigms. Special emphasis is given to joint settings where tasks are shared between two participants. Major conclusions derived from these applications include: (1 Response competition is the chief driver of interference. Likewise, different modes of response competition give rise to different patterns of interference. (2 The type of features in which stimulus and response codes overlap is also a crucial factor. Different types of such features give likewise rise to different patterns of interference. (3 Task sets for joint settings conflate intraindividual conflicts between responses (what, with interindividual conflicts between responding agents (whom. Features of response codes may, therefore, not only address responses, but also responding agents (both physically and socially.

  20. Task representation in individual and joint settings

    Science.gov (United States)

    Prinz, Wolfgang

    2015-01-01

    This paper outlines a framework for task representation and discusses applications to interference tasks in individual and joint settings. The framework is derived from the Theory of Event Coding (TEC). This theory regards task sets as transient assemblies of event codes in which stimulus and response codes interact and shape each other in particular ways. On the one hand, stimulus and response codes compete with each other within their respective subsets (horizontal interactions). On the other hand, stimulus and response code cooperate with each other (vertical interactions). Code interactions instantiating competition and cooperation apply to two time scales: on-line performance (i.e., doing the task) and off-line implementation (i.e., setting the task). Interference arises when stimulus and response codes overlap in features that are irrelevant for stimulus identification, but relevant for response selection. To resolve this dilemma, the feature profiles of event codes may become restructured in various ways. The framework is applied to three kinds of interference paradigms. Special emphasis is given to joint settings where tasks are shared between two participants. Major conclusions derived from these applications include: (1) Response competition is the chief driver of interference. Likewise, different modes of response competition give rise to different patterns of interference; (2) The type of features in which stimulus and response codes overlap is also a crucial factor. Different types of such features give likewise rise to different patterns of interference; and (3) Task sets for joint settings conflate intraindividual conflicts between responses (what), with interindividual conflicts between responding agents (whom). Features of response codes may, therefore, not only address responses, but also responding agents (both physically and socially). PMID:26029085

  1. Task- and age-dependent effects of visual stimulus properties on children's explicit numerosity judgments.

    Science.gov (United States)

    Defever, Emmy; Reynvoet, Bert; Gebuis, Titia

    2013-10-01

    Researchers investigating numerosity processing manipulate the visual stimulus properties (e.g., surface). This is done to control for the confound between numerosity and its visual properties and should allow the examination of pure number processes. Nevertheless, several studies have shown that, despite different visual controls, visual cues remained to exert their influence on numerosity judgments. This study, therefore, investigated whether the impact of the visual stimulus manipulations on numerosity judgments is dependent on the task at hand (comparison task vs. same-different task) and whether this impact changes throughout development. In addition, we examined whether the influence of visual stimulus manipulations on numerosity judgments plays a role in the relation between performance on numerosity tasks and mathematics achievement. Our findings confirmed that the visual stimulus manipulations affect numerosity judgments; more important, we found that these influences changed with increasing age and differed between the comparison and the same-different tasks. Consequently, direct comparisons between numerosity studies using different tasks and age groups are difficult. No meaningful relationship between the performance on the comparison and same-different tasks and mathematics achievement was found in typically developing children, nor did we find consistent differences between children with and without mathematical learning disability (MLD). Copyright © 2013 Elsevier Inc. All rights reserved.

  2. The fate of task-irrelevant visual motion: perceptual load versus feature-based attention.

    Science.gov (United States)

    Taya, Shuichiro; Adams, Wendy J; Graf, Erich W; Lavie, Nilli

    2009-11-18

    We tested contrasting predictions derived from perceptual load theory and from recent feature-based selection accounts. Observers viewed moving, colored stimuli and performed low or high load tasks associated with one stimulus feature, either color or motion. The resultant motion aftereffect (MAE) was used to evaluate attentional allocation. We found that task-irrelevant visual features received less attention than co-localized task-relevant features of the same objects. Moreover, when color and motion features were co-localized yet perceived to belong to two distinct surfaces, feature-based selection was further increased at the expense of object-based co-selection. Load theory predicts that the MAE for task-irrelevant motion would be reduced with a higher load color task. However, this was not seen for co-localized features; perceptual load only modulated the MAE for task-irrelevant motion when this was spatially separated from the attended color location. Our results suggest that perceptual load effects are mediated by spatial selection and do not generalize to the feature domain. Feature-based selection operates to suppress processing of task-irrelevant, co-localized features, irrespective of perceptual load.

  3. Response to Vogelstein: How the 2012 AAP Task Force on circumcision went wrong.

    Science.gov (United States)

    Van Howe, Robert S

    2018-01-01

    Vogelstein cautions medical organizations against jumping into the fray of controversial issues, yet proffers the 2012 American Academy of Pediatrics' Task Force policy position on infant male circumcision as 'an appropriate use of position-statements.' Only a scratch below the surface of this policy statement uncovers the Task Force's failure to consider Vogelstein's many caveats. The Task Force supported the cultural practice by putting undeserved emphasis on questionable scientific data, while ignoring or underplaying the importance of valid contrary scientific data. Without any effort to quantitatively assess the risk/benefit balance, the Task Force concluded the benefits of circumcision outweighed the risks, while acknowledging that the incidence of risks was unknown. This Task Force differed from other Academy policy-forming panels by ignoring the Academy's standard quality measures and by not appointing members with extensive research experience, extensive publications, or recognized expertise directly related to this topic. Despite nearly 100 publications available at the time addressing the substantial ethical issues associated with infant male circumcision, the Task Force chose to ignore the ethical controversy. They merely stated, with minimal justification, the opinion of one of the Task Force members that the practice of infant male circumcision is morally permissible. The release of the report has fostered an explosion of academic discussion on the ethics of infant male circumcision with a number of national medical organizations now decrying the practice as a human rights violation. © 2017 John Wiley & Sons Ltd.

  4. Exploring the Cosmic Frontier, Task A - Direct Detection of Dark Matter, Task B - Experimental Particle Astrophysics

    International Nuclear Information System (INIS)

    Matthews, John A.J.; Gold, Michael S.

    2016-01-01

    This report summarizes the work of Task A and B for the period 2013-2016. For Task A the work is for direct detection of dark matter with the single-phase liquid argon experiment Mini-CLEAN. For Task B the work is for the search for new physics in the analysis of fluorescence events with the Auger experiment and for the search for the indirect detection of dark matter with the HAWC experiment.

  5. Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

    Directory of Open Access Journals (Sweden)

    Hideya Koshino

    Full Text Available BACKGROUND: The anterior prefrontal cortex (PFC exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN, which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. METHODOLOGY/PRINCIPAL FINDINGS: Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition or to ignore them (No face memory condition, then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. CONCLUSIONS/SIGNIFICANCE: The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

  6. Exploring the Cosmic Frontier, Task A - Direct Detection of Dark Matter, Task B - Experimental Particle Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, John A.J. [Univ. of New Mexico, Albuquerque, NM (United States); Gold, Michael S. [Univ. of New Mexico, Albuquerque, NM (United States)

    2016-08-11

    This report summarizes the work of Task A and B for the period 2013-2016. For Task A the work is for direct detection of dark matter with the single-phase liquid argon experiment Mini-CLEAN. For Task B the work is for the search for new physics in the analysis of fluorescence events with the Auger experiment and for the search for the indirect detection of dark matter with the HAWC experiment.

  7. Rules and more rules: the effects of multiple tasks, extensive training, and aging on task-switching performance.

    Science.gov (United States)

    Buchler, Norbou G; Hoyer, William J; Cerella, John

    2008-06-01

    Task-switching performance was assessed in young and older adults as a function of the number of task sets to be actively maintained in memory (varied from 1 to 4) over the course of extended training (5 days). Each of the four tasks required the execution of a simple computational algorithm, which was instantaneously cued by the color of the two-digit stimulus. Tasks were presented in pure (task set size 1) and mixed blocks (task set sizes 2, 3, 4), and the task sequence was unpredictable. By considering task switching beyond two tasks, we found evidence for a cognitive control system that is not overwhelmed by task set size load manipulations. Extended training eliminated age effects in task-switching performance, even when the participants had to manage the execution of up to four tasks. The results are discussed in terms of current theories of cognitive control, including task set inertia and production system postulates.

  8. Exploring relations between task conflict and informational conflict in the Stroop task.

    Science.gov (United States)

    Entel, Olga; Tzelgov, Joseph; Bereby-Meyer, Yoella; Shahar, Nitzan

    2015-11-01

    In this study, we tested the proposal that the Stroop task involves two conflicts--task conflict and informational conflict. Task conflict was defined as the latency difference between color words and non-letter neutrals, and manipulated by varying the proportion of color words versus non-letter neutrals. Informational conflict was defined as the latency difference between incongruent and congruent trials and manipulated by varying the congruent-to-incongruent trial ratio. We replicated previous findings showing that increasing the ratio of incongruent-to-congruent trials reduces the latency difference between the incongruent and congruent condition (i.e., informational conflict), as does increasing the proportion of color words (i.e., task conflict). A significant under-additive interaction between the two proportion manipulations (congruent vs. incongruent and color words vs. neutrals) indicated that the effects of task conflict and informational conflict were not additive. By assessing task conflict as the contrast between color words and neutrals, we found that task conflict existed in all of our experimental conditions. Under specific conditions, when task conflict dominated behavior by explaining most of the variability between congruency conditions, we also found negative facilitation, thus demonstrating that this effect is a special case of task conflict.

  9. The relation between task characteristics, BI quality and task compatibility: An explorative study

    DEFF Research Database (Denmark)

    Gaardboe, Rikke; Jonasen, Tanja Svarre; Nyvang, Tom

    2018-01-01

    The purpose of this article is to investigate the relationship between task characteristics, business intelligence (BI) quality, and task compatibility. It is essential to investigate this relationship, as BI often builds up data from the organization's existing information systems, and thus......, is a supplement. In addition, there is a gap within existing research about task characteristics and BI. We conducted a survey of three companies, where 104 BI end users answered the questionnaire. Our findings reveal that BI users who experience high information quality solve difficult tasks, have a specified...

  10. Performance of a visuomotor walking task in an augmented reality training setting

    NARCIS (Netherlands)

    Haarman, Juliet A.M.; Choi, Julia T.; Buurke, Jaap H.; Rietman, Johan S.; Reenalda, Jasper

    2017-01-01

    Visual cues can be used to train walking patterns. Here, we studied the performance and learning capacities of healthy subjects executing a high-precision visuomotor walking task, in an augmented reality training set-up. A beamer was used to project visual stepping targets on the walking surface of

  11. Automatic Retrieval of Newly Instructed Cue-Task Associations Seen in Task-Conflict Effects in the First Trial after Cue-Task Instructions.

    Science.gov (United States)

    Meiran, Nachshon; Pereg, Maayan

    2017-01-01

    Novel stimulus-response associations are retrieved automatically even without prior practice. Is this true for novel cue-task associations? The experiment involved miniblocks comprising three phases and task switching. In the INSTRUCTION phase, two new stimuli (or familiar cues) were arbitrarily assigned as cues for up-down/right-left tasks performed on placeholder locations. In the UNIVALENT phase, there was no task cue since placeholder's location afforded one task but the placeholders were the stimuli that we assigned as task cues for the following BIVALENT phase (involving target locations affording both tasks). Thus, participants held the novel cue-task associations in memory while executing the UNIVALENT phase. Results show poorer performance in the first univalent trial when the placeholder was associated with the opposite task (incompatible) than when it was compatible, an effect that was numerically larger with newly instructed cues than with familiar cues. These results indicate automatic retrieval of newly instructed cue-task associations.

  12. Are factors related to dual-task performance in people with Parkinson's disease dependent on the type of dual task?

    Science.gov (United States)

    Strouwen, Carolien; Molenaar, Esther A L M; Keus, Samyra H J; Münks, Liesbeth; Heremans, Elke; Vandenberghe, Wim; Bloem, Bastiaan R; Nieuwboer, Alice

    2016-02-01

    Impaired dual-task performance significantly impacts upon functional mobility in people with Parkinson's disease (PD). The aim of this study was to identify determinants of dual-task performance in people with PD in three different dual tasks to assess their possible task-dependency. We recruited 121 home-dwelling patients with PD (mean age 65.93 years; mean disease duration 8.67 years) whom we subjected to regular walking (control condition) and to three dual-task conditions: walking combined with a backwards Digit Span task, an auditory Stroop task and a Mobile Phone task. We measured dual-task gait velocity using the GAITRite mat and dual-task reaction times and errors on the concurrent tasks as outcomes. Motor, cognitive and descriptive variables which correlated to dual-task performance (p task gait velocity and executive function, tested by the alternating intake test, was significantly associated with gait velocity during the Digit Span (R(2) = 0.65; p task (R(2) = 0.62; p task. Age was a surplus determinant of gait velocity while using a mobile phone. Single-task gait velocity and executive function as measured by a verbal fluency switching task were independent determinants of dual-task gait performance in people with PD. In contrast to expectation, these factors were the same across different tasks, supporting the robustness of the findings. Future study needs to determine whether these factors predict dual-task abnormalities prospectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. The Effect of "Massed" Task Repetitions on Complexity, Accuracy and Fluency: Does It Transfer to a New Task?

    Science.gov (United States)

    Ahmadian, Mohammad Javad

    2011-01-01

    To date, research results suggest that task repetition positively affects oral task performance. However, researchers have not yet shown the extension of the benefits of repeating the same task to performance of a new task. This article first provides an overview of the currently available research findings on task repetition and then presents the…

  14. Task Demands in OSCEs Influence Learning Strategies.

    Science.gov (United States)

    Lafleur, Alexandre; Laflamme, Jonathan; Leppink, Jimmie; Côté, Luc

    2017-01-01

    Models on pre-assessment learning effects confirmed that task demands stand out among the factors assessors can modify in an assessment to influence learning. However, little is known about which tasks in objective structured clinical examinations (OSCEs) improve students' cognitive and metacognitive processes. Research is needed to support OSCE designs that benefit students' metacognitive strategies when they are studying, reinforcing a hypothesis-driven approach. With that intent, hypothesis-driven physical examination (HDPE) assessments ask students to elicit and interpret findings of the physical exam to reach a diagnosis ("Examine this patient with a painful shoulder to reach a diagnosis"). When studying for HDPE, students will dedicate more time to hypothesis-driven discussions and practice than when studying for a part-task OSCE ("Perform the shoulder exam"). It is expected that the whole-task nature of HDPE will lead to a hypothesis-oriented use of the learning resources, a frequent use of adjustment strategies, and persistence with learning. In a mixed-methods study, 40 medical students were randomly paired and filmed while studying together for two hypothetical OSCE stations. Each 25-min study period began with video cues asking to study for either a part-task OSCE or an HDPE. In a crossover design, sequences were randomized for OSCEs and contents (shoulder or spine). Time-on-task for discussions or practice were categorized as "hypothesis-driven" or "sequence of signs and maneuvers." Content analysis of focus group interviews summarized students' perception of learning resources, adjustment strategies, and persistence with learning. When studying for HDPE, students allocate significantly more time for hypothesis-driven discussions and practice. Students use resources contrasting diagnoses and report persistence with learning. When studying for part-task OSCEs, time-on-task is reversed, spent on rehearsing a sequence of signs and maneuvers. OSCEs with

  15. Computerized management of plant intervention tasks

    International Nuclear Information System (INIS)

    Quoidbach, G.

    2004-01-01

    The main objective of the 'Computerized Management of Plant Intervention Tasks' is to help the staff of a nuclear or a conventional power plant or of any other complex industrial facility (chemical industries, refineries, and so on) in planning, organizing, and carrying out any (preventive or corrective) maintenance task. This 'Computerized Management of Plant Intervention Tasks' is organized around a data base of all plant components in the facility that might be subjected to maintenance or tagout. It allows to manage, by means of intelligent and configurable 'mail service', the course of the intervention requests as well as various treatments of those requests, in a safe and efficient way, adapted to each particular organization. The concept of 'Computerized Management' of plant intervention tasks was developed by BELGATOM in 1983 for the Belgian nuclear power plants of ELECTRABEL. A first implementation of this concept was made at that time for the Doel NPP under the name POPIT (Programming Of Plant Intervention Tasks). In 1988, it was decided to proceed to a functional upgrade of the application, using advanced software and hardware techniques and products, and to realize a second implementation in the Tihange NPP under the name ACM (Application Consignation Maintenance). (author)

  16. Job and task analysis for technical staff

    International Nuclear Information System (INIS)

    Toline, B.C.

    1991-01-01

    In September of 1989 Cooper Nuclear Station began a project to upgrade the Technical Staff Training Program. This project's roots began by performing job and Task Analysis for Technical Staff. While the industry has long been committed to Job and Task Analysis to target performance based instruction for single job positions, this approach was unique in that it was not originally considered appropriate for a group as diverse as Tech Staff. Much to his satisfaction the Job and Task Analysis Project was much less complicated for Technical Staff than the author had imagined. The benefits of performing the Job and Task Analysis for Technical Staff have become increasingly obvious as he pursues lesson plan development and course revisions. The outline for this presentation will be as follows: philosophy adopted; preparation of the job survey document; performing the job analysis; performing task analysis for technical staff and associated pitfalls; clustering objectives for training and comparison to existing program; benefits now and in the future; final phase (comparison to INPO guides and meeting the needs of non-degreed engineering professionals); and conclusion. By focusing on performance based needs for engineers rather than traditional academics for training the author is confident the future Technical Staff Program will meet the challenges ahead and will exceed requirements for accreditation

  17. Task planning systems with natural language interface

    International Nuclear Information System (INIS)

    Kambayashi, Shaw; Uenaka, Junji

    1989-12-01

    In this report, a natural language analyzer and two different task planning systems are described. In 1988, we have introduced a Japanese language analyzer named CS-PARSER for the input interface of the task planning system in the Human Acts Simulation Program (HASP). For the purpose of a high speed analysis, we have modified a dictionary system of the CS-PARSER by using C language description. It is found that the new dictionary system is very useful for a high speed analysis and an efficient maintenance of the dictionary. For the study of the task planning problem, we have modified a story generating system named Micro TALE-SPIN to generate a story written in Japanese sentences. We have also constructed a planning system with natural language interface by using the CS-PARSER. Task planning processes and related knowledge bases of these systems are explained. A concept design for a new task planning system will be also discussed from evaluations of above mentioned systems. (author)

  18. Surface smoothness

    DEFF Research Database (Denmark)

    Tummala, Sudhakar; Dam, Erik B.

    2010-01-01

    accuracy, such novel markers must therefore be validated against clinically meaningful end-goals such as the ability to allow correct diagnosis. We present a method for automatic cartilage surface smoothness quantification in the knee joint. The quantification is based on a curvature flow method used....... We demonstrate that the fully automatic markers eliminate the time required for radiologist annotations, and in addition provide a diagnostic marker superior to the evaluated semi-manual markers....

  19. Task complexity, student perceptions of vocabulary learning in EFL, and task performance.

    Science.gov (United States)

    Wu, Xiaoli; Lowyck, Joost; Sercu, Lies; Elen, Jan

    2013-03-01

    The study deepened our understanding of how students' self-efficacy beliefs contribute to the context of teaching English as a foreign language in the framework of cognitive mediational paradigm at a fine-tuned task-specific level. The aim was to examine the relationship among task complexity, self-efficacy beliefs, domain-related prior knowledge, learning strategy use, and task performance as they were applied to English vocabulary learning from reading tasks. Participants were 120 second-year university students (mean age 21) from a Chinese university. This experiment had two conditions (simple/complex). A vocabulary level test was first conducted to measure participants' prior knowledge of English vocabulary. Participants were then randomly assigned to one of the learning tasks. Participants were administered task booklets together with the self-efficacy scales, measures of learning strategy use, and post-tests. Data obtained were submitted to multivariate analysis of variance (MANOVA) and path analysis. Results from the MANOVA model showed a significant effect of vocabulary level on self-efficacy beliefs, learning strategy use, and task performance. Task complexity showed no significant effect; however, an interaction effect between vocabulary level and task complexity emerged. Results from the path analysis showed self-efficacy beliefs had an indirect effect on performance. Our results highlighted the mediating role of self-efficacy beliefs and learning strategy use. Our findings indicate that students' prior knowledge plays a crucial role on both self-efficacy beliefs and task performance, and the predictive power of self-efficacy on task performance may lie in its association with learning strategy use. © 2011 The British Psychological Society.

  20. Distraction during learning with hypermedia: Difficult tasks help to keep task goals on track

    Directory of Open Access Journals (Sweden)

    Katharina eScheiter

    2014-03-01

    Full Text Available In educational hypermedia environments, students are often confronted with potential sources of distraction arising from additional information that, albeit interesting, is unrelated to their current task goal. The paper investigates the conditions under which distraction occurs and hampers performance. Based on theories of volitional action control it was hypothesized that interesting information, especially if related to a pending goal, would interfere with task performance only when working on easy, but not on difficult tasks. In Experiment 1, 66 students learned about probability theory using worked examples and solved corresponding test problems, whose task difficulty was manipulated. As a second factor, the presence of interesting information unrelated to the primary task was varied. Results showed that students solved more easy than difficult probability problems correctly. However, the presence of interesting, but task-irrelevant information did not interfere with performance. In Experiment 2, 68 students again engaged in example-based learning and problem solving in the presence of task-irrelevant information. Problem-solving difficulty was varied as a first factor. Additionally, the presence of a pending goal related to the task-irrelevant information was manipulated. As expected, problem-solving performance declined when a pending goal was present during working on easy problems, whereas no interference was observed for difficult problems. Moreover, the presence of a pending goal reduced the time on task-relevant information and increased the time on task-irrelevant information while working on easy tasks. However, as revealed by mediation analyses these changes in overt information processing behavior did not explain the decline in problem-solving performance. As an alternative explanation it is suggested that goal conflicts resulting from pending goals claim cognitive resources, which are then no longer available for learning and

  1. Frontal subregions mediating Elevator Counting task performance.

    Science.gov (United States)

    MacPherson, Sarah E; Turner, Martha S; Bozzali, Marco; Cipolotti, Lisa; Shallice, Tim

    2010-10-01

    Deficits in sustained attention may lead to action slips in everyday life as irrelevant action sequences are inappropriately triggered internally or by the environment. While deficits in sustained attention have been associated with damage to the frontal lobes of the brain, little is known about the role of the frontal lobes in the Elevator Counting subtest of the Test of Everyday Attention. In the current study, 55 frontal patients subdivided into medial, orbital and lateral subgroups, 18 patients with posterior lesions and 82 healthy controls performed the Elevator Counting task. The results revealed that patients with medial and left lateral prefrontal lesions were significantly impaired on the task compared to healthy controls. Research suggests that patients with medial lesions are susceptible to competition from task irrelevant schema; whereas the left lateral group in the current study may fail to keep track of the tones already presented. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Classroom Interactions in a Cooperative Translation Task

    Directory of Open Access Journals (Sweden)

    Hui chuan Wang

    2013-03-01

    Full Text Available For the past decade, translation learning has become one of the main foci for university language students in Taiwan. However, many studies have shown that translation teachers tend to adopt traditional teaching methods without considering class dynamics and student interactions. This paper therefore looks into the interactions in the researcher’s designed cooperative translation task, the Cooperative Translation Task, to see how these interactions helped or hindered students’ translation learning. A small class of 25 translation students and two translation teachers were participants. Videotaping and interviews were conducted in order to investigate the interaction modes and student participants’ perspectives toward each interaction mode. Six interaction modes were found in this task: within group, between group, translator group and comment-giver group, instructor and students, guest teacher and students, and instructor and guest teacher. Based on the results and participants’ responses, suggested teaching guidelines are provided.

  3. Pointing Device Performance in Steering Tasks.

    Science.gov (United States)

    Senanayake, Ransalu; Goonetilleke, Ravindra S

    2016-06-01

    Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants aged 20.1 ± 3.13 years. It was found that, depending on the difficulty of the task, the optimal settings differ for ballistic and visual control tasks. With a touch screen, resting the arm increased movement time for steering tasks. When both performance and comfort are considered, whether to use a mouse or a touch screen for person-computer interaction depends on the steering difficulty. Hence, a input device should be chosen based on the application, and should be optimized to match the graphical user interface. © The Author(s) 2016.

  4. Lessons Learned from Crowdsourcing Complex Engineering Tasks.

    Science.gov (United States)

    Staffelbach, Matthew; Sempolinski, Peter; Kijewski-Correa, Tracy; Thain, Douglas; Wei, Daniel; Kareem, Ahsan; Madey, Gregory

    2015-01-01

    Crowdsourcing is the practice of obtaining needed ideas, services, or content by requesting contributions from a large group of people. Amazon Mechanical Turk is a web marketplace for crowdsourcing microtasks, such as answering surveys and image tagging. We explored the limits of crowdsourcing by using Mechanical Turk for a more complicated task: analysis and creation of wind simulations. Our investigation examined the feasibility of using crowdsourcing for complex, highly technical tasks. This was done to determine if the benefits of crowdsourcing could be harnessed to accurately and effectively contribute to solving complex real world engineering problems. Of course, untrained crowds cannot be used as a mere substitute for trained expertise. Rather, we sought to understand how crowd workers can be used as a large pool of labor for a preliminary analysis of complex data. We compared the skill of the anonymous crowd workers from Amazon Mechanical Turk with that of civil engineering graduate students, making a first pass at analyzing wind simulation data. For the first phase, we posted analysis questions to Amazon crowd workers and to two groups of civil engineering graduate students. A second phase of our experiment instructed crowd workers and students to create simulations on our Virtual Wind Tunnel website to solve a more complex task. With a sufficiently comprehensive tutorial and compensation similar to typical crowd-sourcing wages, we were able to enlist crowd workers to effectively complete longer, more complex tasks with competence comparable to that of graduate students with more comprehensive, expert-level knowledge. Furthermore, more complex tasks require increased communication with the workers. As tasks become more complex, the employment relationship begins to become more akin to outsourcing than crowdsourcing. Through this investigation, we were able to stretch and explore the limits of crowdsourcing as a tool for solving complex problems.

  5. The approach to engineering tasks composition on knowledge portals

    Science.gov (United States)

    Novogrudska, Rina; Globa, Larysa; Schill, Alexsander; Romaniuk, Ryszard; Wójcik, Waldemar; Karnakova, Gaini; Kalizhanova, Aliya

    2017-08-01

    The paper presents an approach to engineering tasks composition on engineering knowledge portals. The specific features of engineering tasks are highlighted, their analysis makes the basis for partial engineering tasks integration. The formal algebraic system for engineering tasks composition is proposed, allowing to set the context-independent formal structures for engineering tasks elements' description. The method of engineering tasks composition is developed that allows to integrate partial calculation tasks into general calculation tasks on engineering portals, performed on user request demand. The real world scenario «Calculation of the strength for the power components of magnetic systems» is represented, approving the applicability and efficiency of proposed approach.

  6. Impact of task design on task performance and injury risk: case study of a simulated drilling task.

    Science.gov (United States)

    Alabdulkarim, Saad; Nussbaum, Maury A; Rashedi, Ehsan; Kim, Sunwook; Agnew, Michael; Gardner, Richard

    2017-06-01

    Existing evidence is limited regarding the influence of task design on performance and ergonomic risk, or the association between these two outcomes. In a controlled experiment, we constructed a mock fuselage to simulate a drilling task common in aircraft manufacturing, and examined the effect of three levels of workstation adjustability on performance as measured by productivity (e.g. fuselage completion time) and quality (e.g. fuselage defective holes), and ergonomic risk as quantified using two common methods (rapid upper limb assessment and the strain index). The primary finding was that both productivity and quality significantly improved with increased adjustability, yet this occurred only when that adjustability succeeded in reducing ergonomic risk. Supporting the inverse association between ergonomic risk and performance, the condition with highest adjustability created the lowest ergonomic risk and the best performance while there was not a substantial difference in ergonomic risk between the other two conditions, in which performance was also comparable. Practitioner Summary: Findings of this study supported a causal relationship between task design and both ergonomic risk and performance, and that ergonomic risk and performance are inversely associated. While future work is needed under more realistic conditions and a broader population, these results may be useful for task (re)design and to help cost-justify some ergonomic interventions.

  7. A Reverse Stroop Task with Mouse Tracking

    OpenAIRE

    Yamamoto, Naohide; Incera, Sara; McLennan, Conor T.

    2016-01-01

    In a reverse Stroop task, observers respond to the meaning of a color word irrespective of the color in which the word is printed—for example, the word red may be printed in the congruent color (red), an incongruent color (e.g., blue), or a neutral color (e.g., white). Although reading of color words in this task is often thought to be neither facilitated by congruent print colors nor interfered with incongruent print colors, this interference has been detected by using a response method that...

  8. REINA at CLEF 2007 Robust Task

    OpenAIRE

    Zazo Rodríguez, Ángel Francisco; Figuerola, Carlos G.; Alonso Berrocal, José Luis

    2007-01-01

    This paper describes our work at CLEF 2007 Robust Task. We have participated in the monolingual (English, French and Portuguese) and the bilingual (English to French) subtask. At CLEF 2006 our research group obtained very good results applying local query expansion using windows of terms in the robust task. This year we have used the same expansion technique, but taking into account some criteria of robustness: MAP, GMAP, MMR, GS@10, P@10, number of failed topics, number of topics bellow 0.1 ...

  9. Radiation protection technician job task analysis manual

    International Nuclear Information System (INIS)

    1990-03-01

    This manual was developed to assist all DOE contractors in the design and conduct of job task analysis (JTA) for the radiation protection technician. Experience throughout the nuclear industry and the DOE system has indicated that the quality and efficiency in conducting a JTA at most sites is greatly enhanced by using a generic task list for the position, and clearly written guidelines on the JTA process. This manual is designed to provide this information for personnel to use in developing and conducting site-specific JTAs. (VC)

  10. Intelligence is differentially related to neural effort in the task-positive and the task-negative brain network

    NARCIS (Netherlands)

    Basten, U.; Stelzel, C.; Fiebach, C.J.

    2013-01-01

    Previous studies on individual differences in intelligence and brain activation during cognitive processing focused on brain regions where activation increases with task demands (task-positive network, TPN). Our study additionally considers brain regions where activation decreases with task demands

  11. Effects of Task Performance and Task Complexity on the Validity of Computational Models of Attention

    NARCIS (Netherlands)

    Koning, L. de; Maanen, P.P. van; Dongen, K. van

    2008-01-01

    Computational models of attention can be used as a component of decision support systems. For accurate support, a computational model of attention has to be valid and robust. The effects of task performance and task complexity on the validity of three different computational models of attention were

  12. "Smart inhibition": electrophysiological evidence for the suppression of conflict-generating task rules during task switching.

    Science.gov (United States)

    Meiran, Nachshon; Hsieh, Shulan; Chang, Chi-Chih

    2011-09-01

    A major challenge for task switching is maintaining a balance between high task readiness and effectively ignoring irrelevant task rules. This calls for finely tuned inhibition that targets only the source of interference without adversely influencing other task-related representations. The authors show that irrelevant task rules generating response conflict are inhibited, causing their inefficient execution on the next trial (indicating the presence of competitor rule suppression[CRS];Meiran, Hsieh, & Dimov, Journal of Experimental Psychology: Learning, Memory and Cognition, 36, 992-1002, 2010). To determine whether CRS influences task rules, rather than target stimuli or responses, the authors focused on the processing of the task cue before the target stimulus was presented and before the response could be chosen. As was predicted, CRS was found in the event-related potentials in two time windows during task cue processing. It was also found in three time windows after target presentation. Source localization analyses suggest the involvement of the right dorsal prefrontal cortex in all five time windows.

  13. Appraisal, Coping, Task Performance, and Cardiovascular Responses during the Evaluated Speaking Task.

    Science.gov (United States)

    Baggett, H. Lane; And Others

    1996-01-01

    Appraisal, coping, task performance, and cardiovascular responses were examined among men high and low in speech anxiety who prepared and performed a speech under evaluative conditions. Speech-anxious men saw the task as more threatening. They were more stressed, anxious, distracted, and aware of their emotions, focused on the passage of time, and…

  14. Physical Education-in-CLIL tasks. Determining tasks characteristics through the analysis of the diaries

    Directory of Open Access Journals (Sweden)

    Josep Coral Mateu

    2013-07-01

    Full Text Available This article focuses on the characteristics of Physical Education-in-CLIL (PE-in-CLIL tasks. CLIL (Content and Language Integrated Learning is a teaching approach which uses foreign language as a tool to enhance the subject learning process. We connect PE-in-CLIL with key competences and we introduce the CLIL 4Cs framework. We establish the aims of the study, that is; to describe the features of tasks which are most suitable to PE-in-CLIL and identify integrated tasks which appeal most to learners. We use Action-Research and we collect data through diaries. The participants of the study were twenty-six learners of 5th grade of primary school. We described the strategies of rigour and quality applied and we analysed data using a qualitative data analysis software programme (NVivo. In the results, we identify both the tasks that appeal to students and the tasks that are developed successfully. In the conclusions, we provide teaching guidelines to plan successful PE-in-CLIL tasks that appeal to students. At this point, we emphasise tasks that combined both cooperative learning and oracy with motor activity and games. We also declare the necessity of incorporating scaffolding strategies in order to accommodate students’ linguistic needs and facilitate tasks development. Future CLIL research possibilities emerge in the Physical Education field of work.

  15. Respiratory sinus arrhythmia responses to cognitive tasks : effects of task factors and RSA indices

    NARCIS (Netherlands)

    Overbeek, T.; Boxtel, van Anton; Westerink, J.H.D.M.

    2014-01-01

    Many studies show that respiratory sinus arrhythmia (RSA) decreases while performing cognitive tasks. However, there is uncertainty about the role of contaminating factors such as physical activity and stress-inducing task variables. Different methods to quantify RSA may also contribute to variable

  16. Respiratory sinus arrhythmia responses to cognitive tasks: Effects of task factors and RSA indices

    NARCIS (Netherlands)

    Overbeek, T.J.M.; van Boxtel, A.; Westerink, J.H.D.M.

    2014-01-01

    Many studies show that respiratory sinus arrhythmia (RSA) decreases while performing cognitive tasks. However, there is uncertainty about the role of contaminating factors such as physical activity and stress-inducing task variables. Different methods to quantify RSA may also contribute to variable

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

    Science.gov (United States)

    Rubin, Joan

    2015-01-01

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

  18. A Nonword Repetition Task for Speakers with Misarticulations: The Syllable Repetition Task (SRT)

    Science.gov (United States)

    Shriberg, Lawrence D.; Lohmeier, Heather L.; Campbell, Thomas F.; Dollaghan, Christine A.; Green, Jordan R.; Moore, Christopher A.

    2009-01-01

    Purpose: Conceptual and methodological confounds occur when non(sense) word repetition tasks are administered to speakers who do not have the target speech sounds in their phonetic inventories or who habitually misarticulate targeted speech sounds. In this article, the authors (a) describe a nonword repetition task, the Syllable Repetition Task…

  19. The Effect of Writing Task and Task Conditions on Colombian EFL Learners' Language Use

    Science.gov (United States)

    McDonough, Kim; Fuentes, César García

    2015-01-01

    This classroom study examines whether English L2 writers' language use differs depending on the writing task (operationalized as paragraph type), and task conditions (operationalized as individual or collaborative writing). The texts written by English L2 university students in Colombia (N = 26) in response to problem/solution and cause/effect…

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

    Science.gov (United States)

    Judd, Terry

    2015-01-01

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

  1. Task Complexity, Student Perceptions of Vocabulary Learning in EFL, and Task Performance

    Science.gov (United States)

    Wu, Xiaoli; Lowyck, Joost; Sercu, Lies; Elen, Jan

    2013-01-01

    Background: The study deepened our understanding of how students' self-ef?cacy beliefs contribute to the context of teaching English as a foreign language in the framework of cognitive mediational paradigm at a ?ne-tuned task-speci?c level. Aim: The aim was to examine the relationship among task complexity, self-ef?cacy beliefs, domain-related…

  2. The Role of Task Complexity, Modality, and Aptitude in Narrative Task Performance

    Science.gov (United States)

    Kormos, Judit; Trebits, Anna

    2012-01-01

    The study reported in this paper investigated the relationship between components of aptitude and the fluency, lexical variety, syntactic complexity, and accuracy of performance in two types of written and spoken narrative tasks. We also addressed the question of how narrative performance varies in tasks of different cognitive complexity in the…

  3. Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Diagnostic Task Force Criteria Impact of New Task Force Criteria

    NARCIS (Netherlands)

    Cox, Moniek G. P. J.; van der Smagt, Jasper J.; Noorman, Maartje; Wiesfeld, Ans C.; Volders, Paul G. A.; van Langen, Irene M.; Atsma, Douwe E.; Dooijes, Dennis; Houweling, Arjan C.; Loh, Peter; Jordaens, Luc; Arens, Yvonne; Cramer, Maarten J.; Doevendans, Pieter A.; van Tintelen, Peter; Wilde, Arthur A. M.; Hauer, Richard N. W.

    Background-Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) Diagnostic Task Force Criteria (TFC) proposed in 1994 are highly specific but lack sensitivity. A new international task force modified criteria to improve diagnostic yield. A comparison of diagnosis by 1994 TFC versus

  4. Osmosis and Surface Area to Volume Ratio.

    Science.gov (United States)

    Barrett, D. R. B.

    1984-01-01

    Describes an experiment designed to help students understand the concepts of osmosis and surface area to volume ratio (SA:VOL). The task for students is to compare water uptake in different sizes of potato cubes and relate differences to their SA:VOL ratios. (JN)

  5. Respiratory sinus arrhythmia responses to cognitive tasks: effects of task factors and RSA indices.

    Science.gov (United States)

    Overbeek, Thérèse J M; van Boxtel, Anton; Westerink, Joyce H D M

    2014-05-01

    Many studies show that respiratory sinus arrhythmia (RSA) decreases while performing cognitive tasks. However, there is uncertainty about the role of contaminating factors such as physical activity and stress-inducing task variables. Different methods to quantify RSA may also contribute to variable results. In 83 healthy subjects, we studied RSA responses to a working memory task requiring varying levels of cognitive control and a perceptual attention task not requiring strong cognitive control. RSA responses were quantified in the time and frequency domain and were additionally corrected for differences in mean interbeat interval and respiration rate, resulting in eight different RSA indices. The two tasks were clearly differentiated by heart rate and facial EMG reference measures. Cognitive control induced inhibition of RSA whereas perceptual attention generally did not. However, the results show several differences between different RSA indices, emphasizing the importance of methodological variables. Age and sex did not influence the results. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Task conflict and proactive control: A computational theory of the Stroop task.

    Science.gov (United States)

    Kalanthroff, Eyal; Davelaar, Eddy J; Henik, Avishai; Goldfarb, Liat; Usher, Marius

    2018-01-01

    The Stroop task is a central experimental paradigm used to probe cognitive control by measuring the ability of participants to selectively attend to task-relevant information and inhibit automatic task-irrelevant responses. Research has revealed variability in both experimental manipulations and individual differences. Here, we focus on a particular source of Stroop variability, the reverse-facilitation (RF; faster responses to nonword neutral stimuli than to congruent stimuli), which has recently been suggested as a signature of task conflict. We first review the literature that shows RF variability in the Stroop task, both with regard to experimental manipulations and to individual differences. We suggest that task conflict variability can be understood as resulting from the degree of proactive control that subjects recruit in advance of the Stroop stimulus. When the proactive control is high, task conflict does not arise (or is resolved very quickly), resulting in regular Stroop facilitation. When proactive control is low, task conflict emerges, leading to a slow-down in congruent and incongruent (but not in neutral) trials and thus to Stroop RF. To support this suggestion, we present a computational model of the Stroop task, which includes the resolution of task conflict and its modulation by proactive control. Results show that our model (a) accounts for the variability in Stroop-RF reported in the experimental literature, and (b) solves a challenge to previous Stroop models-their ability to account for reaction time distributional properties. Finally, we discuss theoretical implications to Stroop measures and control deficits observed in some psychopathologies. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  7. 3D Printed Potential and Free Energy Surfaces for Teaching Fundamental Concepts in Physical Chemistry

    Science.gov (United States)

    Kaliakin, Danil S.; Zaari, Ryan R.; Varganov, Sergey A.

    2015-01-01

    Teaching fundamental physical chemistry concepts such as the potential energy surface, transition state, and reaction path is a challenging task. The traditionally used oversimplified 2D representation of potential and free energy surfaces makes this task even more difficult and often confuses students. We show how this 2D representation can be…

  8. Development of the Biology Card Sorting Task to Measure Conceptual Expertise in Biology

    Science.gov (United States)

    Smith, Julia I.; Combs, Elijah D.; Nagami, Paul H.; Alto, Valerie M.; Goh, Henry G.; Gourdet, Muryam A. A.; Hough, Christina M.; Nickell, Ashley E.; Peer, Adrian G.; Coley, John D.; Tanner, Kimberly D.

    2013-01-01

    There are widespread aspirations to focus undergraduate biology education on teaching students to think conceptually like biologists; however, there is a dearth of assessment tools designed to measure progress from novice to expert biological conceptual thinking. We present the development of a novel assessment tool, the Biology Card Sorting Task, designed to probe how individuals organize their conceptual knowledge of biology. While modeled on tasks from cognitive psychology, this task is unique in its design to test two hypothesized conceptual frameworks for the organization of biological knowledge: 1) a surface feature organization focused on organism type and 2) a deep feature organization focused on fundamental biological concepts. In this initial investigation of the Biology Card Sorting Task, each of six analytical measures showed statistically significant differences when used to compare the card sorting results of putative biological experts (biology faculty) and novices (non–biology major undergraduates). Consistently, biology faculty appeared to sort based on hypothesized deep features, while non–biology majors appeared to sort based on either surface features or nonhypothesized organizational frameworks. Results suggest that this novel task is robust in distinguishing populations of biology experts and biology novices and may be an adaptable tool for tracking emerging biology conceptual expertise. PMID:24297290

  9. Common Developmental Tasks in Forming Reconstituted Families.

    Science.gov (United States)

    Kleinman, Judith

    1979-01-01

    Developmental tasks common to the formation of a reconstituted family are described, particularly the continued mourning of the old family; the formation of a solid marital relationship despite the difficulties presented by past failures and the presence of children; and the formation of sibling alliances across family lines. (Author)

  10. A Cognitive Task Analysis for Dental Hygiene.

    Science.gov (United States)

    Cameron, Cheryl A.; Beemsterboer, Phyllis L.; Johnson, Lynn A.; Mislevy, Robert J.; Steinberg, Linda S.; Breyer, F. Jay

    2000-01-01

    As part of the development of a scoring algorithm for a simulation-based dental hygiene initial licensure examination, this effort conducted a task analysis of the dental hygiene domain. Broad classes of behaviors that distinguish along the dental hygiene expert-novice continuum were identified and applied to the design of nine paper-based cases…

  11. Efficient Workplan Management in Maintenance Tasks

    NARCIS (Netherlands)

    Wilson, M.; Roos, N.; Huisman, B.; Witteveen, C.

    2011-01-01

    NedTrain is a Dutch company tasked with performing the maintenance of the rolling stock of the national railway company, NS. NedTrain owns several workshops at different locations. The scheduling in one such workshop will be taken as point of departure for the discussion in this paper. After

  12. Pair Negotiation When Developing English Speaking Tasks

    Science.gov (United States)

    Bohórquez Suárez, Ingrid Liliana; Gómez Sará, Mary Mily; Medina Mosquera, Sindy Lorena

    2011-01-01

    This study analyzes what characterizes the negotiations of seventh graders at a public school in Bogotá when working in pairs to develop speaking tasks in EFL classes. The inquiry is a descriptive case study that follows the qualitative paradigm. As a result of analyzing the data, we obtained four consecutive steps that characterize students'…

  13. Department of Defense Recovering Warrior Task Force

    Science.gov (United States)

    2014-09-02

    accessible and available to the Veterans Benefits Administration ( VBA ) as soon as possible381; however, because military service records include health...programs are meeting expectations ........................................... 35 Facilitating Access to Health Care...Enduring RW Mission, Facilitating RW Recovery and Transition, and Facilitating Access to Health Care. SUMMARY 2  DoD Recovering Warrior Task Force

  14. Task Characteristics, Managerial Socialization, and Media Selection.

    Science.gov (United States)

    Donabedian, Bairj; McKinnon, Sharon M.; Bruns, William J., Jr.

    1998-01-01

    Questions why managers choose one communication medium in preference to another. Proposes a role for social factors in media selection. Finds, employing a large field-collected sample, strong support for Information Richness Theory, a rational-choice model connecting managers' media choice to task characteristics like variety and analyzability.…

  15. Division of household tasks and financial management

    NARCIS (Netherlands)

    Antonides, G.

    2011-01-01

    Both the standard economic model and bargaining theory make predictions about financial management and the division of household labor between household partners. Using a large Internet survey, we have tested several predictions about task divisions reported by Dutch household partners. The division

  16. VUJE tasks and activities during gradual upgrading

    International Nuclear Information System (INIS)

    Ferenc, M.

    2001-01-01

    The paper describes the organization and management of the Gradual Upgrading of the Bohunice V1 NPP and the principle tasks and scope of activities provided by VUJE Trnava, Inc. It also describes the system of supplies and the system of quality assurance both in the consortium and in subcontractors. (author)

  17. Conflict Management at School: An Unavoidable Task.

    Science.gov (United States)

    Bondesio, Mike J.

    Conflict management has become an integral part of a headmaster's tasks. Headmasters are not required to suppress or resolve conflict, but to manage it. Since 1976, conflict in black schools has increased, and headmasters have had to manage serious and dangerous situations. Unfortunately, there has been little research in conflict management in…

  18. Geometry task sheets : grades 3-5

    CERN Document Server

    Rosenberg, Mary

    2009-01-01

    For grades 3-5, our Common Core State Standards-based resource meets the geometry concepts addressed by the NCTM standards and encourages the students to learn and review the concepts in unique ways. Each task sheet is organized around a central problem taken from real-life experiences of the students.

  19. Algebra task sheets : grades pk-2

    CERN Document Server

    Reed, Nat

    2009-01-01

    For grades PK-2, our Common Core State Standards-based resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to learn and review the concepts in unique ways. Each task sheet is organized around a central problem taken from real-life experiences of the students.

  20. Geometry task sheets : grades pk-2

    CERN Document Server

    Rosenberg, Mary

    2009-01-01

    For grades PK-2, our Common Core State Standards-based resource meets the geometry concepts addressed by the NCTM standards and encourages the students to learn and review the concepts in unique ways. Each task sheet is organized around a central problem taken from real-life experiences of the students.