Fluid Physics and Macromolecular Crystal Growth in Microgravity

NASA Technical Reports Server (NTRS)

Pusey, M.; Snell, E.; Judge, R.; Chayen, N.; Boggon, T.; Helliwell, J.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The molecular structure of biological macromolecules is important in understanding how these molecules work and has direct application to rational drug design for new medicines and for the improvement and development of industrial enzymes. In order to obtain the molecular structure, large, well formed, single macromolecule crystals are required. The growth of macromolecule crystals is a difficult task and is often hampered on the ground by fluid flows that result from the interaction of gravity with the crystal growth process. One such effect is the bulk movement of the crystal through the fluid due to sedimentation. A second is buoyancy driven convection close to the crystal surface. On the ground the crystallization process itself induces both of these flows.

Online monitoring of Mezcal fermentation based on redox potential measurements.

PubMed

Escalante-Minakata, P; Ibarra-Junquera, V; Rosu, H C; De León-Rodríguez, A; González-García, R

2009-01-01

We describe an algorithm for the continuous monitoring of the biomass and ethanol concentrations as well as the growth rate in the Mezcal fermentation process. The algorithm performs its task having available only the online measurements of the redox potential. The procedure combines an artificial neural network (ANN) that relates the redox potential to the ethanol and biomass concentrations with a nonlinear observer-based algorithm that uses the ANN biomass estimations to infer the growth rate of this fermentation process. The results show that the redox potential is a valuable indicator of the metabolic activity of the microorganisms during Mezcal fermentation. In addition, the estimated growth rate can be considered as a direct evidence of the presence of mixed culture growth in the process. Usually, mixtures of microorganisms could be intuitively clear in this kind of processes; however, the total biomass data do not provide definite evidence by themselves. In this paper, the detailed design of the software sensor as well as its experimental application is presented at the laboratory level.

Chemical vapor deposition growth

NASA Technical Reports Server (NTRS)

Ruth, R. P.; Manasevit, H. M.; Campbell, A. G.; Johnson, R. E.; Kenty, J. L.; Moudy, L. A.; Shaw, G. L.; Simpson, W. I.; Yang, J. J.

1978-01-01

The objective was to investigate and develop chemical vapor deposition (CVD) techniques for the growth of large areas of Si sheet on inexpensive substrate materials, with resulting sheet properties suitable for fabricating solar cells that would meet the technical goals of the Low Cost Silicon Solar Array Project. The program involved six main technical tasks: (1) modification and test of an existing vertical-chamber CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using impurity diffusion and other standard and near-standard processing techniques supplemented late in the program by the in situ CVD growth of n(+)/p/p(+) sheet structures subsequently processed into experimental cells.

Laser-zone growth in a Ribbon-To-Ribbon (RTR) process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Gurtler, R. W.; Baghdadi, A.; Wise, J.; Ellis, R. J.

1977-01-01

The Ribbon-to-Ribbon (RTR) approach to silicon ribbon growth was investigated. An existing RTR apparatus, RTR#1, was upgraded to allow for 5 cm wide ribbon growth with a finite stroke length of at least 15 cm. A second RTR apparatus, RTR#2, was designed, built, and operated which utilizes continuous feed mechanisms and allows continuous growth of 7.5 cm wide ribbons. RTR#2 includes development and utilization of advanced beam scanning (or shaping), high power lasers, and thermal profile modification elements to attain maximum growth velocities (with a design goal of 18 cm/min). Materials studies, process development, and thermal analyses are also described. Residual stresses and dislocation densities were minimized through theoretical and experimental efforts towards optimization of thermal profiles. Growth runs were performed on RTR#2 and solar cells were fabricated which demonstrated efficiencies greater than 10%.

From photons to big-data applications: terminating terabits

PubMed Central

2016-01-01

Computer architectures have entered a watershed as the quantity of network data generated by user applications exceeds the data-processing capacity of any individual computer end-system. It will become impossible to scale existing computer systems while a gap grows between the quantity of networked data and the capacity for per system data processing. Despite this, the growth in demand in both task variety and task complexity continues unabated. Networked computer systems provide a fertile environment in which new applications develop. As networked computer systems become akin to infrastructure, any limitation upon the growth in capacity and capabilities becomes an important constraint of concern to all computer users. Considering a networked computer system capable of processing terabits per second, as a benchmark for scalability, we critique the state of the art in commodity computing, and propose a wholesale reconsideration in the design of computer architectures and their attendant ecosystem. Our proposal seeks to reduce costs, save power and increase performance in a multi-scale approach that has potential application from nanoscale to data-centre-scale computers. PMID:26809573

From photons to big-data applications: terminating terabits.

PubMed

Zilberman, Noa; Moore, Andrew W; Crowcroft, Jon A

2016-03-06

Computer architectures have entered a watershed as the quantity of network data generated by user applications exceeds the data-processing capacity of any individual computer end-system. It will become impossible to scale existing computer systems while a gap grows between the quantity of networked data and the capacity for per system data processing. Despite this, the growth in demand in both task variety and task complexity continues unabated. Networked computer systems provide a fertile environment in which new applications develop. As networked computer systems become akin to infrastructure, any limitation upon the growth in capacity and capabilities becomes an important constraint of concern to all computer users. Considering a networked computer system capable of processing terabits per second, as a benchmark for scalability, we critique the state of the art in commodity computing, and propose a wholesale reconsideration in the design of computer architectures and their attendant ecosystem. Our proposal seeks to reduce costs, save power and increase performance in a multi-scale approach that has potential application from nanoscale to data-centre-scale computers. © 2016 The Authors.

Task-Driven Dynamic Text Summarization

ERIC Educational Resources Information Center

Workman, Terri Elizabeth

2011-01-01

The objective of this work is to examine the efficacy of natural language processing (NLP) in summarizing bibliographic text for multiple purposes. Researchers have noted the accelerating growth of bibliographic databases. Information seekers using traditional information retrieval techniques when searching large bibliographic databases are often…

Fostering Cognitive Growth Through Writing.

ERIC Educational Resources Information Center

Sternglass, Marilyn S.

Recent research studies and texts in composition demonstrate the growing belief that students' difficulties with the writing tasks assigned to them are inextricably linked with their difficulties in handling complex cognitive processes. Through appropriate writing activities, students can be provided with practice in the intellectual functions…

Silicon materials task of the low cost solar array project. Phase 3: Effect of impurities and processing on silicon solar cells

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Davis, J. R.; Blais, P. D.; Rohatgi, A.; Campbell, R. B.; Rai-Choudhury, P.; Mollenkopf, H. C.; Mccormick, J. R.

1979-01-01

The 13th quarterly report of a study entitled an Investigation of the Effects of Impurities and Processing on Silicon Solar Cells is given. The objective of the program is to define the effects of impurities, various thermochemical processes and any impurity-process interactions on the performance of terrestrial silicon solar cells. The Phase 3 program effort falls in five areas: (1) cell processing studies; (2) completion of the data base and impurity-performance modeling for n-base cells; (3) extension of p-base studies to include contaminants likely to be introduced during silicon production, refining or crystal growth; (4) anisotropy effects; and (5) a preliminary study of the permanence of impurity effects in silicon solar cells. The quarterly activities for this report focus on tasks (1), (3) and (4).

Laser-zone growth in a Ribbon-To-Ribbon, RTR, process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Gurtler, R. W.; Baghdadi, A.

1977-01-01

A ribbon-to-ribbon process was used for routine growth of samples for analysis and fabrication into solar cells. One lot of solar cells was completely evaluated: ribbon solar cell efficiencies averaged 9.23% with a highest efficiency of 11.7%. Spherical reflectors have demonstrated significant improvements in laser silicon coupling efficiencies. Material analyses were performed including silicon photovoltage and open circuit photovoltage diffusion length measurements, crystal morphology studies, modulus of rupture measurements, and annealing/gettering studies. An initial economic analysis was performed indicating that ribbon-to-ribbon add-on costs of $.10/watt might be expected in the early 1980's.

Heat exchanger-ingot casting/slicing process, phase 1: Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Schmid, F.; Khattak, C. P.

1977-01-01

A controlled growth, heat-flow and cool-down process is described that yielded silicon with a high degree of single crystallinity. Even when the seed melted out, very large grains formed. Solar cell samples made from cast material yielded conversion efficiency of over 9%. Representative characterizations of grown silicon demonstrated a dislocation density of less than 100/sq cm and a minority carrier diffusion length of 31 micron. The source of silicon carbide in silicon ingots was identified to be from graphite retainers in contact with silica crucibles. Higher growth rates were achieved with the use of a graphite plug at the bottom of the silica crucible.

Family environment influences emotion recognition following paediatric traumatic brain injury.

PubMed

Schmidt, Adam T; Orsten, Kimberley D; Hanten, Gerri R; Li, Xiaoqi; Levin, Harvey S

2010-01-01

This study investigated the relationship between family functioning and performance on two tasks of emotion recognition (emotional prosody and face emotion recognition) and a cognitive control procedure (the Flanker task) following paediatric traumatic brain injury (TBI) or orthopaedic injury (OI). A total of 142 children (75 TBI, 67 OI) were assessed on three occasions: baseline, 3 months and 1 year post-injury on the two emotion recognition tasks and the Flanker task. Caregivers also completed the Life Stressors and Resources Scale (LISRES) on each occasion. Growth curve analysis was used to analyse the data. Results indicated that family functioning influenced performance on the emotional prosody and Flanker tasks but not on the face emotion recognition task. Findings on both the emotional prosody and Flanker tasks were generally similar across groups. However, financial resources emerged as significantly related to emotional prosody performance in the TBI group only (p = 0.0123). Findings suggest family functioning variables--especially financial resources--can influence performance on an emotional processing task following TBI in children.

Low cost solar array project. Task 1: Silicon material, gaseous melt replenishment system

NASA Technical Reports Server (NTRS)

Jewett, D. N.; Bates, H. E.; Hill, D. M.

1979-01-01

A system to combine silicon formation, by hydrogen reduction of trichlorosilane, with the capability to replenish a crystal growth system is described. A variety of process parameters to allow sizing and specification of gas handling system components was estimated.

Effect of solvents on the bulk growth of 4-aminobenzophenone single crystals: A potential material for blue and green lasers

NASA Astrophysics Data System (ADS)

Natarajan, V.; Usharani, S.; Arivanandhan, M.; Anandan, P.; Hayakawa, Y.

2015-06-01

Although 4-aminobenzophenone (4-ABP) is the best derivative of benzophenone with 260 times higher second harmonic generation (SHG) efficiency than potassium dihydrogen phosphate (KDP), growth of high quality bulk crystal still remains a difficult task. In the present work, the effect of solvents on solubility and growth aspects of 4-ABP was investigated to grow inclusion free 4-ABP crystals. The growth processes were discussed based on solute-solvent interaction in two different growth media of ethyl acetate and ethanol. The growth rate and thereby solvent inclusions are relatively higher in ethyl acetate grown crystal than the crystal grown from ethanol. The structural, thermal and optical properties of 4-ABP crystals were studied. The enthalpy of 4-ABP melting process was estimated from differential thermal analysis. The optical transmission study shows that 4-ABP crystals grown from ethanol has high transparency compared to ethyl acetate grown sample due to solvent inclusion in the later crystal.

Yield model development project implementation plan

NASA Technical Reports Server (NTRS)

Ambroziak, R. A.

1982-01-01

Tasks remaining to be completed are summarized for the following major project elements: (1) evaluation of crop yield models; (2) crop yield model research and development; (3) data acquisition processing, and storage; (4) related yield research: defining spectral and/or remote sensing data requirements; developing input for driving and testing crop growth/yield models; real time testing of wheat plant process models) and (5) project management and support.

Onboard experiment data support facility. Task 2 report: Definition of onboard processing requirements

NASA Technical Reports Server (NTRS)

1976-01-01

The onboard experiment data support facility (OEDSF) will provide data processing support to various experiment payloads on board the space shuttle. The OEDSF study will define the conceptual design and generate specifications for an OEDSF which will meet the following objectives: (1) provide a cost-effective approach to end-to-end processing requirements, (2) service multiple disciplines (3) satisfy user needs, (4) reduce the amount and improve the quality of data collected, stored and processed, and (5) embody growth capacity.

Low Angle Silicon Sheet Growth. Large Area Silicon Sheet Task Low Cost Solar Array Project

NASA Technical Reports Server (NTRS)

1982-01-01

The results of a program to demonstrate the feasibility of a low angle silicon ribbon growth process are described. Twenty-six experimental runs were performed. Ribbons were grown at pull rates from 5 to 68 cm/min. Ribbon lengths up to 74 cm were grown while widths varied from 5 to 25 mm. Thicknesses varied from 0.6 to 2.5 mm, with typical values of about 1 mm.

Image processing and recognition for biological images.

PubMed

Uchida, Seiichi

2013-05-01

This paper reviews image processing and pattern recognition techniques, which will be useful to analyze bioimages. Although this paper does not provide their technical details, it will be possible to grasp their main tasks and typical tools to handle the tasks. Image processing is a large research area to improve the visibility of an input image and acquire some valuable information from it. As the main tasks of image processing, this paper introduces gray-level transformation, binarization, image filtering, image segmentation, visual object tracking, optical flow and image registration. Image pattern recognition is the technique to classify an input image into one of the predefined classes and also has a large research area. This paper overviews its two main modules, that is, feature extraction module and classification module. Throughout the paper, it will be emphasized that bioimage is a very difficult target for even state-of-the-art image processing and pattern recognition techniques due to noises, deformations, etc. This paper is expected to be one tutorial guide to bridge biology and image processing researchers for their further collaboration to tackle such a difficult target. © 2013 The Author Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment.

PubMed

Liu, Qi; Cai, Weidong; Jin, Dandan; Shen, Jian; Fu, Zhangjie; Liu, Xiaodong; Linge, Nigel

2016-08-30

Distributed Computing has achieved tremendous development since cloud computing was proposed in 2006, and played a vital role promoting rapid growth of data collecting and analysis models, e.g., Internet of things, Cyber-Physical Systems, Big Data Analytics, etc. Hadoop has become a data convergence platform for sensor networks. As one of the core components, MapReduce facilitates allocating, processing and mining of collected large-scale data, where speculative execution strategies help solve straggler problems. However, there is still no efficient solution for accurate estimation on execution time of run-time tasks, which can affect task allocation and distribution in MapReduce. In this paper, task execution data have been collected and employed for the estimation. A two-phase regression (TPR) method is proposed to predict the finishing time of each task accurately. Detailed data of each task have drawn interests with detailed analysis report being made. According to the results, the prediction accuracy of concurrent tasks' execution time can be improved, in particular for some regular jobs.

Process modelling for materials preparation experiments

NASA Technical Reports Server (NTRS)

Rosenberger, Franz; Alexander, J. Iwan D.

1993-01-01

The main goals of the research under this grant consist of the development of mathematical tools and measurement of transport properties necessary for high fidelity modeling of crystal growth from the melt and solution, in particular, for the Bridgman-Stockbarger growth of mercury cadmium telluride (MCT) and the solution growth of triglycine sulphate (TGS). Of the tasks described in detail in the original proposal, two remain to be worked on: (1) development of a spectral code for moving boundary problems; and (2) diffusivity measurements on concentrated and supersaturated TGS solutions. Progress made during this seventh half-year period is reported.

Laser-zone growth in a Ribbon-To-Ribbon (RTR) process, silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Gurtler, R. W.; Baghdadi, A.

1976-01-01

The objective of this research is to fully investigate the Ribbon-To-Ribbon (R-T-R) approach to silicon ribbon growth. Initial work has concentrated on modification and characterization of an existing R-T-R apparatus. In addition, equipment for auxiliary heating of the melt is being evaluated and acquired. Modification of the remote viewing system and mechanical staging are nearly complete. Characterization of the laser and other components is in progress and several auxiliary heating techniques are being investigated.

Arizona Community Colleges: Report of the Task Force on Community College Enrollment Growth Planning.

ERIC Educational Resources Information Center

Arizona State Board of Directors for Community Colleges, Phoenix.

The Task Force on Enrollment Growth Planning (TFEGP), authorized in 1992 by the State Board of Directors for Community Colleges (SBDCC) of Arizona, includes representatives from each community college as well as staff from SBDCC office. The Task Force was created to prepare enrollment growth estimates for community colleges through the year 2010;…

The growth of materials processing in space - A history of government support for new technology

NASA Technical Reports Server (NTRS)

Mckannan, E. C.

1983-01-01

Development of a given technology for national defense and large systems developments when the task is too large or risky for entrepreneurs, yet is clearly in the best interest of the nation are discussed. Advanced research to identify areas of interest was completed. Examples of commercial opportunities are the McDonnell-Douglas Corporation purification process for pharmaceutical products and the Microgravity Research Associates process for growing gallium arsenide crystals in space.

Measuring Leaf Area in Soy Plants by HSI Color Model Filtering and Mathematical Morphology

NASA Astrophysics Data System (ADS)

Benalcázar, M.; Padín, J.; Brun, M.; Pastore, J.; Ballarin, V.; Peirone, L.; Pereyra, G.

2011-12-01

There has been lately a significant progress in automating tasks for the agricultural sector. One of the advances is the development of robots, based on computer vision, applied to care and management of soy crops. In this task, digital image processing plays an important role, but must solve some important problems, like the ones associated to the variations in lighting conditions during image acquisition. Such variations influence directly on the brightness level of the images to be processed. In this paper we propose an algorithm to segment and measure automatically the leaf area of soy plants. This information is used by the specialists to evaluate and compare the growth of different soy genotypes. This algorithm, based on color filtering using the HSI model, detects green objects from the image background. The segmentation of leaves (foliage) was made applying Mathematical Morphology. The foliage area was estimated counting the pixels that belong to the segmented leaves. From several experiments, consisting in applying the algorithm to measure the foliage of about fifty plants of various genotypes of soy, at different growth stages, we obtained successful results, despite the high brightness variations and shadows in the processed images.

Step-by-step growth of complex oxide microstructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datskos, Panos G.; Cullen, David A.; Sharma, Jaswinder K.

The synthesis of complex and hybrid oxide microstructures is of fundamental interest and practical applications. However, the design and synthesis of such structures is a challenging task. A solution-phase process to synthesize complex silica and silica-titania hybrid microstructures was developed by exploiting the emulsion-droplet-based step-by-step growth featuring shape control. Lastly, the strategy is robust and can be extended to the preparation of complex hybrid structures consisting of two or more materials, with each having its own shape.

Step-by-step growth of complex oxide microstructures

DOE PAGES

Datskos, Panos G.; Cullen, David A.; Sharma, Jaswinder K.

2015-06-10

The synthesis of complex and hybrid oxide microstructures is of fundamental interest and practical applications. However, the design and synthesis of such structures is a challenging task. A solution-phase process to synthesize complex silica and silica-titania hybrid microstructures was developed by exploiting the emulsion-droplet-based step-by-step growth featuring shape control. Lastly, the strategy is robust and can be extended to the preparation of complex hybrid structures consisting of two or more materials, with each having its own shape.

Family environment influences emotion recognition following paediatric traumatic brain injury

PubMed Central

SCHMIDT, ADAM T.; ORSTEN, KIMBERLEY D.; HANTEN, GERRI R.; LI, XIAOQI; LEVIN, HARVEY S.

2011-01-01

Objective This study investigated the relationship between family functioning and performance on two tasks of emotion recognition (emotional prosody and face emotion recognition) and a cognitive control procedure (the Flanker task) following paediatric traumatic brain injury (TBI) or orthopaedic injury (OI). Methods A total of 142 children (75 TBI, 67 OI) were assessed on three occasions: baseline, 3 months and 1 year post-injury on the two emotion recognition tasks and the Flanker task. Caregivers also completed the Life Stressors and Resources Scale (LISRES) on each occasion. Growth curve analysis was used to analyse the data. Results Results indicated that family functioning influenced performance on the emotional prosody and Flanker tasks but not on the face emotion recognition task. Findings on both the emotional prosody and Flanker tasks were generally similar across groups. However, financial resources emerged as significantly related to emotional prosody performance in the TBI group only (p = 0.0123). Conclusions Findings suggest family functioning variables—especially financial resources—can influence performance on an emotional processing task following TBI in children. PMID:21058900

Development of advanced Czochralski growth process to produce low cost 150 kg silicon ingots from a single crucible for technology readiness

NASA Technical Reports Server (NTRS)

1981-01-01

The process development continued, with a total of nine crystal growth runs. One of these was a 150 kg run of 5 crystals of approximately 30 kg each. Several machine and process problems were corrected and the 150 kg run was as successful as previous long runs on CG2000 RC's. The accelerated recharge and growth will be attempted when the development program resumes at full capacity in FY '82. The automation controls (Automatic Grower Light Computer System) were integrated to the seed dip temperature, shoulder, and diameter sensors on the CG2000 RC development grower. Test growths included four crystals, which were grown by the computer/sensor system from seed dip through tail off. This system will be integrated on the Mod CG2000 grower during the next quarter. The analytical task included the completion and preliminary testing of the gas chromatograph portion of the Furnace Atmosphere Analysis System. The system can detect CO concentrations and will be expanded to oxygen and water analysis in FY '82.

Floating substrate process: Large-area silicon sheet task low-cost solar array project

NASA Technical Reports Server (NTRS)

Garfinkel, M.; Hall, R. N.

1978-01-01

Supercooling of silicon-tin alloy melts was studied. Values as high as 78 C at 1100 C and 39 C at 1200 C were observed, corresponding to supersaturation parameter values 0.025 and 0.053 at 1050 C and 1150 C, respectively. The interaction of tin with silane gas streams was investigated over the temperature range 1000 to 1200 C. Single-pass conversion efficiencies exceeding 30% were obtained. The growth habit of spontaneously-nucleated surface growth was determined to be consistent with dendritic and web growth from singly-twinned triangular nucleii. Surface growth of interlocking silicon crystals, thin enough to follow the surface of the liquid and with growth velocity as high as 5 mm/min, was obtained. Large area single-crystal growth along the melt surface was not achieved. Small single-crystal surface growth was obtained which did not propagate beyond a few millimeters.

NeuroRhythmics: software for analyzing time-series measurements of saltatory movements in neuronal processes.

PubMed

Kerlin, Aaron M; Lindsley, Tara A

2008-08-15

Time-lapse imaging of living neurons both in vivo and in vitro has revealed that the growth of axons and dendrites is highly dynamic and characterized by alternating periods of extension and retraction. These growth dynamics are associated with important features of neuronal development and are differentially affected by experimental treatments, but the underlying cellular mechanisms are poorly understood. NeuroRhythmics was developed to semi-automate specific quantitative tasks involved in analysis of two-dimensional time-series images of processes that exhibit saltatory elongation. This software provides detailed information on periods of growth and nongrowth that it identifies by transitions in elongation (i.e. initiation time, average rate, duration) and information regarding the overall pattern of saltatory growth (i.e. time of pattern onset, frequency of transitions, relative time spent in a state of growth vs. nongrowth). Plots and numeric output are readily imported into other applications. The user has the option to specify criteria for identifying transitions in growth behavior, which extends the potential application of the software to neurons of different types or developmental stage and to other time-series phenomena that exhibit saltatory dynamics. NeuroRhythmics will facilitate mechanistic studies of periodic axonal and dendritic growth in neurons.

Direct integration of polycrystalline graphene into light emitting diodes by plasma-assisted metal-catalyst-free synthesis.

PubMed

Kim, Yong Seung; Joo, Kisu; Jerng, Sahng-Kyoon; Lee, Jae Hong; Moon, Daeyoung; Kim, Jonghak; Yoon, Euijoon; Chun, Seung-Hyun

2014-03-25

The integration of graphene into devices is a challenging task because the preparation of a graphene-based device usually includes graphene growth on a metal surface at elevated temperatures (∼1000 °C) and a complicated postgrowth transfer process of graphene from the metal catalyst. Here we report a direct integration approach for incorporating polycrystalline graphene into light emitting diodes (LEDs) at low temperature by plasma-assisted metal-catalyst-free synthesis. Thermal degradation of the active layer in LEDs is negligible at our growth temperature, and LEDs could be fabricated without a transfer process. Moreover, in situ ohmic contact formation is observed between DG and p-GaN resulting from carbon diffusion into the p-GaN surface during the growth process. As a result, the contact resistance is reduced and the electrical properties of directly integrated LEDs outperform those of LEDs with transferred graphene electrodes. This relatively simple method of graphene integration will be easily adoptable in the industrialization of graphene-based devices.

Criterion Referenced Assessment: Delineating Curricular Related Performance Skills Necessary for the Development of a Table of Test Specifications

ERIC Educational Resources Information Center

MacQuarrie, David; Applegate, Brooks; Lacefield, Warren

2008-01-01

This study focused on defining and delineating core skills and tasks needed for successful CTE student educational growth and success through a curriculum and assessment alignment process. The context for this project lies within Automotive Service Technology (AST), which must additionally meet the National Institute of Automotive Service…

Online Adaptation for Mobile Device Text Input Personalization

ERIC Educational Resources Information Center

Baldwin, Tyler

2012-01-01

As mobile devices have become more common, the need for efficient methods of mobile device text entry has grown. With this growth comes new challenges, as the constraints imposed by the size, processing power, and design of mobile devices impairs traditional text entry mechanisms in ways not seen in previous text entry tasks. To combat this,…

Real time quantitative imaging for semiconductor crystal growth, control and characterization

NASA Technical Reports Server (NTRS)

Wargo, Michael J.

1991-01-01

A quantitative real time image processing system has been developed which can be software-reconfigured for semiconductor processing and characterization tasks. In thermal imager mode, 2D temperature distributions of semiconductor melt surfaces (900-1600 C) can be obtained with temperature and spatial resolutions better than 0.5 C and 0.5 mm, respectively, as demonstrated by analysis of melt surface thermal distributions. Temporal and spatial image processing techniques and multitasking computational capabilities convert such thermal imaging into a multimode sensor for crystal growth control. A second configuration of the image processing engine in conjunction with bright and dark field transmission optics is used to nonintrusively determine the microdistribution of free charge carriers and submicron sized crystalline defects in semiconductors. The IR absorption characteristics of wafers are determined with 10-micron spatial resolution and, after calibration, are converted into charge carrier density.

Effects of daily noise on fetuses and cerebral hemisphere specialization in children

NASA Astrophysics Data System (ADS)

Ando, Y.

1988-12-01

This paper first provides an overview of work by the author and colleagues on effects of noise on fetuses demonstrating growth inhibition. As a second issue, the effects of daily noise on the mental abilities of children are discussed in relation to task specification of cerebral hemispheres. Two different types of mental tasks were given to a total of 1286 children (7-10 years old) who live in a noisy area around an international airport or in a neighbouring quiet area, under conditions of no sound, jet-plane noise stimulus and music stimulus. In the quiet neighborhood, results may support a model that noise and calculation tasks are separately processed in the right and left cerebral hemisphere, respectively. Music perception and calculation are considered to be processed one after the other in the left hemisphere. In the pattern search task used as the right hemispheric task, no significant differences appeared under either stimulus sound, with the exception of a slight interference observed in the noise group. In the noisy living area, however, effects of temporary sound on mental tasks appeared to be quite different from the first-mentioned results. These facts suggest that daily noise affects the development of cerebral specialization of growing children. As little is known about effects of noise on growing children, it is recommended that international cooperation be initiated to establish the need for and conditions of healthy sound environments.

Bridging the Gap: Individual Growth and Development Indicators--The Which One Doesn't Belong Task

ERIC Educational Resources Information Center

Rodriguez, Megan I.; Wackerle-Hollman, Alisha K.

2015-01-01

The Individual Growth and Development Indicator (IGDI): Which One Doesn't Belong (WODB) task is an early comprehension screening assessment designed for use in pre-Kindergarten multi-tiered systems of support. This article summarizes the purpose, procedures, and evidence base currently available in the literature to support the WODB task. Example…

Laser-zone Growth in a Ribbon-to-ribbon (RTR) Process Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Solar Array Project

NASA Technical Reports Server (NTRS)

Baghdadi, A.; Gurtler, R. W.; Legge, R.; Sopori, B.; Rice, M. J.; Ellis, R. J.

1979-01-01

A technique for growing limited-length ribbons continually was demonstrated. This Rigid Edge technique can be used to recrystallize about 95% of the polyribbon feedstock. A major advantage of this method is that only a single, constant length silicon ribbon is handled throughout the entire process sequence; this may be accomplished using cassettes similar to those presently in use for processing Czochralski waters. Thus a transition from Cz to ribbon technology can be smoothly affected. The maximum size being considered, 3 inches x 24 inches, is half a square foot, and will generate 6 watts for 12% efficiency at 1 sun. Silicon dioxide has been demonstrated as an effective, practical diffusion barrier for use during the polyribbon formation.

Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment

PubMed Central

Liu, Qi; Cai, Weidong; Jin, Dandan; Shen, Jian; Fu, Zhangjie; Liu, Xiaodong; Linge, Nigel

2016-01-01

Distributed Computing has achieved tremendous development since cloud computing was proposed in 2006, and played a vital role promoting rapid growth of data collecting and analysis models, e.g., Internet of things, Cyber-Physical Systems, Big Data Analytics, etc. Hadoop has become a data convergence platform for sensor networks. As one of the core components, MapReduce facilitates allocating, processing and mining of collected large-scale data, where speculative execution strategies help solve straggler problems. However, there is still no efficient solution for accurate estimation on execution time of run-time tasks, which can affect task allocation and distribution in MapReduce. In this paper, task execution data have been collected and employed for the estimation. A two-phase regression (TPR) method is proposed to predict the finishing time of each task accurately. Detailed data of each task have drawn interests with detailed analysis report being made. According to the results, the prediction accuracy of concurrent tasks’ execution time can be improved, in particular for some regular jobs. PMID:27589753

Analysing Students' Shared Activity while Modeling a Biological Process in a Computer-Supported Educational Environment

ERIC Educational Resources Information Center

Ergazaki, M.; Zogza, V.; Komis, V.

2007-01-01

This paper reports on a case study with three dyads of high school students (age 14 years) each collaborating on a plant growth modeling task in the computer-supported educational environment "ModelsCreator". Following a qualitative line of research, the present study aims at highlighting the ways in which the collaborating students as well as the…

Silicon on ceramic process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Zook, J. D.; Heaps, J. D.; Maciolek, R. B.; Koepke, B. G.; Butter, C. D.; Schuldt, S. B.

1977-01-01

The technical and economic feasibility of producing solar-cell-quality sheet silicon was investigated. The sheets were made by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress was made in all areas of the program.

When Task Conflict Becomes Personal: The Impact of Perceived Team Performance.

PubMed

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

2016-10-01

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.

When Task Conflict Becomes Personal

PubMed Central

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

Fundamental Concepts of Digital Image Processing

DOE R&D Accomplishments Database

Twogood, R. E.

1983-03-01

The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digital image processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

Crystal Growth and Other Materials Physical Researches in Space Environment

NASA Astrophysics Data System (ADS)

Pan, Mingxiang

Material science researches in space environment are based on reducing the effects of buoyancy driven transport, the effects of atomic oxygen, radiation, extremes of heat and cold and the ultrahigh vacuum, so as to unveil the underlying fundamental phenomena, lead maybe to new potential materials or new industrial processes and develop space techniques. Currently, research program on materials sciences in Chinese Manned Space Engineering (CMSE) is going on. More than ten projects related to crystal growth and materials processes are selected as candidates to be executed in Shenzhou spacecraft, Tiangong Space Laboratory and Chinese Space Station. In this talk, we will present some examples of the projects, which are being prepared and executed in the near future flight tasks. They are both basic and applied research, from discovery to technology.

Applying Task-Technology Fit Model to the Healthcare Sector: a Case Study of Hospitals' Computed Tomography Patient-Referral Mechanism.

PubMed

Chen, Ping-Shun; Yu, Chun-Jen; Chen, Gary Yu-Hsin

2015-08-01

With the growth in the number of elderly and people with chronic diseases, the number of hospital services will need to increase in the near future. With myriad of information technologies utilized daily and crucial information-sharing tasks performed at hospitals, understanding the relationship between task performance and information system has become a critical topic. This research explored the resource pooling of hospital management and considered a computed tomography (CT) patient-referral mechanism between two hospitals using the information system theory framework of Task-Technology Fit (TTF) model. The TTF model could be used to assess the 'match' between the task and technology characteristics. The patient-referral process involved an integrated information framework consisting of a hospital information system (HIS), radiology information system (RIS), and picture archiving and communication system (PACS). A formal interview was conducted with the director of the case image center on the applicable characteristics of TTF model. Next, the Icam DEFinition (IDEF0) method was utilized to depict the As-Is and To-Be models for CT patient-referral medical operational processes. Further, the study used the 'leagility' concept to remove non-value-added activities and increase the agility of hospitals. The results indicated that hospital information systems could support the CT patient-referral mechanism, increase hospital performance, reduce patient wait time, and enhance the quality of care for patients.

A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor.

PubMed

Shakhawath Hossain, Md; Bergstrom, D J; Chen, X B

2015-12-01

The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process. © 2015 Wiley Periodicals, Inc.

Longitudinal Growth Curves of Brain Function Underlying Inhibitory Control through Adolescence

PubMed Central

Foran, William; Velanova, Katerina; Luna, Beatriz

2013-01-01

Neuroimaging studies suggest that developmental improvements in inhibitory control are primarily supported by changes in prefrontal executive function. However, studies are contradictory with respect to how activation in prefrontal regions changes with age, and they have yet to analyze longitudinal data using growth curve modeling, which allows characterization of dynamic processes of developmental change, individual differences in growth trajectories, and variables that predict any interindividual variability in trajectories. In this study, we present growth curves modeled from longitudinal fMRI data collected over 302 visits (across ages 9 to 26 years) from 123 human participants. Brain regions within circuits known to support motor response control, executive control, and error processing (i.e., aspects of inhibitory control) were investigated. Findings revealed distinct developmental trajectories for regions within each circuit and indicated that a hierarchical pattern of maturation of brain activation supports the gradual emergence of adult-like inhibitory control. Mean growth curves of activation in motor response control regions revealed no changes with age, although interindividual variability decreased with development, indicating equifinality with maturity. Activation in certain executive control regions decreased with age until adolescence, and variability was stable across development. Error-processing activation in the dorsal anterior cingulate cortex showed continued increases into adulthood and no significant interindividual variability across development, and was uniquely associated with task performance. These findings provide evidence that continued maturation of error-processing abilities supports the protracted development of inhibitory control over adolescence, while motor response control regions provide early-maturing foundational capacities and suggest that some executive control regions may buttress immature networks as error processing continues to mature. PMID:24227721

OpenMS: a flexible open-source software platform for mass spectrometry data analysis.

PubMed

Röst, Hannes L; Sachsenberg, Timo; Aiche, Stephan; Bielow, Chris; Weisser, Hendrik; Aicheler, Fabian; Andreotti, Sandro; Ehrlich, Hans-Christian; Gutenbrunner, Petra; Kenar, Erhan; Liang, Xiao; Nahnsen, Sven; Nilse, Lars; Pfeuffer, Julianus; Rosenberger, George; Rurik, Marc; Schmitt, Uwe; Veit, Johannes; Walzer, Mathias; Wojnar, David; Wolski, Witold E; Schilling, Oliver; Choudhary, Jyoti S; Malmström, Lars; Aebersold, Ruedi; Reinert, Knut; Kohlbacher, Oliver

2016-08-30

High-resolution mass spectrometry (MS) has become an important tool in the life sciences, contributing to the diagnosis and understanding of human diseases, elucidating biomolecular structural information and characterizing cellular signaling networks. However, the rapid growth in the volume and complexity of MS data makes transparent, accurate and reproducible analysis difficult. We present OpenMS 2.0 (http://www.openms.de), a robust, open-source, cross-platform software specifically designed for the flexible and reproducible analysis of high-throughput MS data. The extensible OpenMS software implements common mass spectrometric data processing tasks through a well-defined application programming interface in C++ and Python and through standardized open data formats. OpenMS additionally provides a set of 185 tools and ready-made workflows for common mass spectrometric data processing tasks, which enable users to perform complex quantitative mass spectrometric analyses with ease.

The Role of Functional Amyloids in Multicellular Growth and Development of Gram-Positive Bacteria.

PubMed

Dragoš, Anna; Kovács, Ákos T; Claessen, Dennis

2017-08-07

Amyloid fibrils play pivotal roles in all domains of life. In bacteria, these fibrillar structures are often part of an extracellular matrix that surrounds the producing organism and thereby provides protection to harsh environmental conditions. Here, we discuss the role of amyloid fibrils in the two distant Gram-positive bacteria, Streptomyces coelicolor and Bacillus subtilis . We describe how amyloid fibrils contribute to a multitude of developmental processes in each of these systems, including multicellular growth and community development. Despite this variety of tasks, we know surprisingly little about how their assembly is organized to fulfill all these roles.

Silicon-on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

1979-01-01

The technical and economic feasibility of producing solar cell-quality silicon was investigated. This was done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress in the following areas was demonstrated: (1) fabricating a 10 sq cm cell having 9.9 percent conversion efficiency; (2) producing a 225 sq cm layer of sheet silicon; and (3) obtaining 100 microns thick coatings at pull speed of 0.15 cm/sec, although approximately 50 percent of the layer exhibited dendritic growth.

Silicon-on-ceramic process: Silicon sheet growth and device development for the large-area silicon sheet task of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Whitehead, A. B.; Zook, J. D.; Grung, B. L.; Heaps, J. D.; Schmit, F.; Schuldt, S. B.; Chapman, P. W.

1981-01-01

The technical feasibility of producing solar cell quality sheet silicon to meet the DOE 1986 cost goal of 70 cents/watt was investigated. The silicon on ceramic approach is to coat a low cost ceramic substrate with large grain polycrystalline silicon by unidirectional solidification of molten silicon. Results and accomplishments are summarized.

Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2012-01-01

Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

CVD-Enabled Graphene Manufacture and Technology

PubMed Central

2015-01-01

Integrated manufacturing is arguably the most challenging task in the development of technology based on graphene and other 2D materials, particularly with regard to the industrial demand for “electronic-grade” large-area films. In order to control the structure and properties of these materials at the monolayer level, their nucleation, growth and interfacing needs to be understood to a level of unprecedented detail compared to existing thin film or bulk materials. Chemical vapor deposition (CVD) has emerged as the most versatile and promising technique to develop graphene and 2D material films into industrial device materials and this Perspective outlines recent progress, trends, and emerging CVD processing pathways. A key focus is the emerging understanding of the underlying growth mechanisms, in particular on the role of the required catalytic growth substrate, which brings together the latest progress in the fields of heterogeneous catalysis and classic crystal/thin-film growth. PMID:26240694

Making space for the inner guide.

PubMed

Leijssen, Mia

2007-01-01

The therapeutic relationship is described as a curative factor in its own right as well as facilitative for other tasks. Experiential tasks that facilitate working on the intrapsychic, interpersonal, and existential domains are distinguished. Focusing is an intrapsychic task of paying attention to one's bodily felt experience. Clearing space helps clients finding a right distance for exploring their experience when they are too close or too distanced from their emotions. Interpersonal work takes the lead when maladaptive interactional patterns are hindering the relational life of the client. Metacommunicative feedback and interpersonal experiences in the therapeutic encounter act as an invitation to develop new ways of communicating. Existential processes are challenged when the client struggles with the givens of life. Finally, the "inner guide" found in accessing experiencing may involve an awareness of a transcendent dimension that leads one to spiritual growth. Vignettes from short term psychotherapy illustrate how this approach is established in practice.

Two homolog wheat Glycogen Synthase Kinase 3/SHAGGY--like kinases are involved in brassinosteroid signaling.

PubMed

Bittner, Thomas; Nadler, Sabine; Schulze, Eija; Fischer-Iglesias, Christiane

2015-10-13

Glycogen Synthase Kinase 3/SHAGGY-like kinases (GSKs) are multifunctional non-receptor ser/thr kinases. Plant GSKs are involved in hormonal signaling networks and are required for growth, development, light as well as stress responses. So far, most studies have been carried out on Arabidopsis or on other eudicotyledon GSKs. Here, we evaluated the role of TaSK1 and TaSK2, two homolog wheat (Triticum aestivum) GSKs, in brassinosteroid signaling. We explored in addition the physiological effects of brassinosteroids on wheat growth and development. A bin2-1 like gain-of-function mutation has been inserted respectively in one of the homoeologous gene copies of TaSK1 (TaSK1-A.2-1) and in one of the homoeologous gene copies of TaSK2 (TaSK2-A.2-1). Arabidopsis plants were transformed with these mutated gene copies. Severe dwarf phenotypes were obtained closely resembling those of Arabidopsis bin2-1 lines and Arabidopsis BR-deficient or BR-signaling mutants. Expression of BR downstream genes, SAUR-AC1, CPD and BAS1 was deregulated in TaSK1.2-1 and TaSK2.2-1 transgenic lines. Severe dwarf lines were partially rescued by Bikinin beforehand shown to inhibit TaSK kinase activity. This rescue was accompanied with changes in BR downstream gene expression levels. Wheat embryos and seedlings were treated with compounds interfering with BR signaling or modifying BR levels to gain insight into the role of brassinosteroids in wheat development. Embryonic axis and scutellum differentiation were impaired, and seedling growth responses were affected when embryos were treated with Epibrassinolides, Propiconazole, and Bikinin. In view of our findings, TaSKs are proposed to be involved in BR signaling and to be orthologous of Arabidopsis Clade II GSK3/SHAGGY-like kinases. Observed effects of Epibrassinolide, Propiconazole and Bikinin treatments on wheat embryos and seedlings indicate a role for BR signaling in embryonic patterning and seedling growth.

Predicting Growth in Word Level Reading Skills in Children With Developmental Dyslexia Using an Object Rhyming Functional Neuroimaging Task.

PubMed

Farris, Emily A; Ring, Jeremiah; Black, Jeffrey; Lyon, G Reid; Odegard, Timothy N

2016-04-01

An object rhyming task that does not require text reading and is suitable for younger children was used to predict gains in word level reading skills following an intensive 2-year reading intervention for children with developmental dyslexia. The task evoked activation in bilateral inferior frontal regions. Growth in untimed pseudoword reading was associated with increased pre-intervention activation of the left inferior frontal gyrus, and growth in timed word reading was associated with pre-intervention activation of the left and right inferior frontal gyri. These analyses help identify pre-intervention factors that facilitate reading skill improvements in children with developmental dyslexia.

Coming of age in an ant colony: cephalic muscle maturation accompanies behavioral development in Pheidole dentata

NASA Astrophysics Data System (ADS)

Muscedere, Mario L.; Traniello, James F. A.; Gronenberg, Wulfila

2011-09-01

Although several neurobiological and genetic correlates of aging and behavioral development have been identified in social insect workers, little is known about how other age-related physiological processes, such as muscle maturation, contribute to task performance. We examined post-eclosion growth of three major muscles of the head capsule in major and minor workers of the ant Pheidole dentata using workers of different ages with distinct task repertoires. Mandible closer muscle fibers, which provide bite force and are thus critical for the use of the mandibles for biting and load carrying, fill the posterio-lateral portions of the head capsule in mature, older workers of both subcastes. Mandible closer fibers of newly eclosed workers, in contrast, are significantly thinner in both subcastes and grow during at least the next 6 days in minor workers, suggesting this muscle has reduced functionality for a substantial period of adult life and thus constrains task performance capability. Fibers of the antennal muscles and the pharynx dilator, which control antennal movements and food intake, respectively, also increase significantly in thickness with age. However, these fibers are only slightly thinner in newly eclosed workers and attain their maximum thickness over a shorter time span in minors. The different growth rates of these functionally distinct muscles likely have consequences for how adult P. dentata workers, particularly minors, develop their full and diverse task repertoire as they age. Workers may be capable of feeding and interacting socially soon after eclosion, but require a longer period of development to effectively use their mandibles, which enable the efficient performance of tasks ranging from nursing to foraging and defense.

General mental ability and two types of adaptation to unforeseen change: applying discontinuous growth models to the task-change paradigm.

PubMed

Lang, Jonas W B; Bliese, Paul D

2009-03-01

The present research provides new insights into the relationship between general mental ability (GMA) and adaptive performance by applying a discontinuous growth modeling framework to a study of unforeseen change on a complex decision-making task. The proposed framework provides a way to distinguish 2 types of adaptation (transition adaptation and reacquisition adaptation) from 2 common performance components (skill acquisition and basal task performance). Transition adaptation refers to an immediate loss of performance following a change, whereas reacquisition adaptation refers to the ability to relearn a changed task over time. Analyses revealed that GMA was negatively related to transition adaptation and found no evidence for a relationship between GMA and reacquisition adaptation. The results are integrated within the context of adaptability research, and implications of using the described discontinuous growth modeling framework to study adaptability are discussed. (c) 2009 APA, all rights reserved.

Insulin growth factor-I promotes functional recovery after a focal lesion in the dentate gyrus.

PubMed

Liquitaya-Montiel, Adhemar; Aguilar-Arredondo, Andrea; Arias, Clorinda; Zepeda, Angélica

2012-11-01

The adult brain is plastic and able to reorganize structurally and functionally after damage. Growth factors are key molecules underlying the recovery process and among trophic molecules, Insulin-Like Growth Factor-I (IGF-I) is of particular interest given that it modulates neuronal and glial responses in the hippocampus including neurogenesis, which has been proposed as a mechanism of neurorepair. In this study we analyzed the effect of intracerebroventricular chronic infusion of IGF-I on functional recovery and morphological restoration after the induction of an excitotoxic lesion in the dentate gyrus (DG) of young-adult rats. Our results show that the lesion impairs contextual fear memory which is a DG dependent task, but not cued fear memory or performance in the open field motor task, which are independent of the DG integrity. Chronic administration of IGF-I, but not vehicle, promotes functional recovery to control levels in injured subjects. Analysis in NeuN immunoprocessed tissue revealed that the lesion volume was not different between groups and that the DG was not evidently restructured in the IGF-I treated group. Glial fibrillary acidic protein (GFAP) analysis revealed an increased astrocytic response in the injured region in both groups and Doublecortin (DCX) analysis showed a similar increase in number of newly born neurons in both groups. However, a remarkable increase in young neurons dendritic arborization was observed in the IGF-I treated group. These results provide evidence for IGF-I as a molecule mediating functional and cellular plasticity during a reorganization process after damage to a neurogenic niche.

Sustaining Optimal Motivation: A Longitudinal Analysis of Interventions to Broaden Participation of Underrepresented Students in STEM

PubMed Central

Hernandez, Paul R.; Schultz, P. Wesley; Estrada, Mica; Woodcock, Anna; Chance, Randie C.

2013-01-01

The underrepresentation of racial minorities and women in science, technology, engineering, and mathematics (STEM) disciplines is a national concern. Goal theory provides a useful framework from which to understand issues of underrepresentation. We followed a large sample of high-achieving African American and Latino undergraduates in STEM disciplines attending 38 institutions of higher education in the United States over 3 academic years. We report on the science-related environmental factors and person factors that influence the longitudinal regulation of goal orientations. Further, we examine how goal orientations in turn influence distal academic outcomes such as performance and persistence in STEM. Using SEM-based parallel process latent growth curve modeling, we found that (a) engagement in undergraduate research was the only factor that buffered underrepresented students against an increase in performance-avoidance goals over time; (b) growth in scientific self-identity exhibited a strong positive effect on growth in task and performance-approach goals over time; (c) only task goals positively influenced students' cumulative grade point average, over and above baseline grade point average; and (d) performance-avoidance goals predicted student attrition from the STEM pipeline. We discuss the implications of these findings for underrepresented students in STEM disciplines. PMID:24273342

Scientific Literacy in Seventh Grade Life Science: A Study of Instructional Process, Task Completion, Student Perceptions, and Learning Outcomes. Final Report of the Intermediate Life Science Study. Secondary Science and Mathematics Improvement Program.

ERIC Educational Resources Information Center

Mitman, Alexis L.; And Others

This 10-chapter report provides detailed information on a study which examined what combinations of teacher, student, and curricular variables were associated with more effective life science instruction at the intermediate level. The conception of effectiveness was guided by the normative framework of scientific literacy and by student growth on…

Kinase-Mediated Regulation of 40S Ribosome Assembly in Human Breast Cancer

DTIC Science & Technology

2017-02-01

Major Task 2 and Major Task 3 (i) CRISPR /cas9-deleted Ltv1-null TNBC clones that have been purified by Dr. Karbstein by growth in the presence of...cells using CRISPR /Cas9 technology proved difficult, as our hypothesis was correct, where Ltv1 is essential for proper growth of TNBC. In particular

Relation between CBM-R and CBM-mR Slopes: An Application of Latent Growth Modeling

ERIC Educational Resources Information Center

Yeo, Seungsoo; Fearrington, Jamie Y.; Christ, Theodore J.

2012-01-01

Oral reading tasks and Maze reading tasks are often used interchangeably to assess the level and rate of reading skill development. This study examined the concurrent validity of growth estimates derived from "Curriculum-Based Measurement of Oral Reading" (CBM-R) and "Maze Reading" (CBM-mR). Participants were 1,528 students…

Task Force II: Energy and Its Socioeconomic Impacts

ERIC Educational Resources Information Center

Appalachia, 1977

1977-01-01

Summarizing the Task Force Issues Paper presented at the Appalachian Conference on Balanced Growth and Economic Development (1977), this article presents selected comments by Task Force participants, and Task Force recommendations re: a national severence tax on extraction of nonrenewable energy resources; socioeconomic costs of nuclear energy; a…

Fluid Physics and Macromolecular Crystal Growth in Microgravity

NASA Technical Reports Server (NTRS)

Pusey, M.; Snell, E.; Judge, R.; Chayen, N.; Boggon, T.

2000-01-01

The molecular structure of biological macromolecules is important in understanding how these molecules work and has direct application to rational drug design for new medicines and for the improvement and development of industrial enzymes. In order to obtain the molecular structure, large, well formed, single macromolecule crystals are required. The growth of macromolecule crystals is a difficult task and is often hampered on the ground by fluid flows that result from the interaction of gravity with the crystal growth process. One such effect is the bulk movement of the crystal through the fluid due to sedimentation. A second is buoyancy driven convection close to the crystal surface. On the ground the crystallization process itself induces both of these flows. Buoyancy driven convection results from density differences between the bulk solution and fluid close to the crystal surface which has been depleted of macromolecules due to crystal growth. Schlieren photograph of a growing lysozyme crystal illustrating a 'growth plume' resulting from buoyancy driven convection. Both sedimentation and buoyancy driven convection have a negative effect on crystal growth and microgravity is seen as a way to both greatly reduce sedimentation and provide greater stability for 'depletion zones' around growing crystals. Some current crystal growth hardware however such as those based on a vapor diffusion techniques, may also be introducing unwanted Marangoni convection which becomes more pronounced in microgravity. Negative effects of g-jitter on crystal growth have also been observed. To study the magnitude of fluid flows around growing crystals we have attached a number of different fluorescent probes to lysozyme molecules. At low concentrations, less than 40% of the total protein, the probes do not appear to effect the crystal growth process. By using these probes we expect to determine not only the effect of induced flows due to crystal growth hardware design but also hope to optimize crystallization hardware so that destructive flows are minimized both on the ground and in microgravity.

Neutron Imaging Reveals Internal Plant Hydraulic Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, Jeffrey; Bilheux, Hassina Z; Kang, Misun

2013-01-01

Many terrestrial ecosystem processes are constrained by water availability and transport within the soil. Knowledge of plant water fluxes is thus critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolution of root structure and xylem water transport dynamics has been a particularly daunting task for the ecologist. Through neutron imaging, we demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings growing in a sandy medium. Root structure and growth were readily imaged by neutron radiography and neutron computed tomography. Seedlings were irrigated with watermore » or deuterium oxide and imaged through time as a growth lamp was cycled on to alter leaf demand for water. Sub-millimeter scale resolution reveals timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages, relationships not well characterized by other techniques.« less

Identification and control of a multizone crystal growth furnace

NASA Technical Reports Server (NTRS)

Batur, C.; Sharpless, R. B.; Duval, W. M. B.; Rosenthal, B. N.; Singh, N. B.

1992-01-01

This paper presents an intelligent adaptive control system for the control of a solid-liquid interface of a crystal while it is growing via directional solidification inside a multizone transparent furnace. The task of the process controller is to establish a user-specified axial temperature profile and to maintain a desirable interface shape. Both single-input-single-output and multi-input-multi-output adaptive pole placement algorithms have been used to control the temperature. Also described is an intelligent measurement system to assess the shape of the crystal while it is growing. A color video imaging system observes the crystal in real time and determines the position and the shape of the interface. This information is used to evaluate the crystal growth rate, and to analyze the effects of translational velocity and temperature profiles on the shape of the interface. Creation of this knowledge base is the first step to incorporate image processing into furnace control.

Analysis of defect structure in silicon. Silicon sheet growth development for the large area silicon sheet task of the Low-Cost Solar array Project

NASA Technical Reports Server (NTRS)

Natesh, R.; Mena, M.; Plichta, M.; Smith, J. M.; Sellani, M. A.

1982-01-01

One hundred ninety-three silicon sheet samples, approximately 880 square centimeters, were analyzed for twin boundary density, dislocation pit density, and grain boundary length. One hundred fifteen of these samples were manufactured by a heat exchanger method, thirty-eight by edge defined film fed growth, twenty-three by the silicon on ceramics process, and ten by the dendritic web process. Seven solar cells were also step-etched to determine the internal defect distribution on these samples. Procedures were developed or the quantitative characterization of structural defects such as dislocation pits, precipitates, twin & grain boundaries using a QTM 720 quantitative image analyzing system interfaced with a PDP 11/03 mini computer. Characterization of the grain boundary length per unit area for polycrystalline samples was done by using the intercept method on an Olympus HBM Microscope.

RoadPlex: A Mobile VGI Game to Collect and Validate Data for POIs

NASA Astrophysics Data System (ADS)

Kashian, A.; Rajabifard, A.; Richter, K. F.

2014-11-01

By increasing the popularity of smart phones equipped with GPS sensors, more volunteers are expected to join VGI (Volunteered Geographic Information) activities and therefore more positional data will be collected in shorter time. Current statistics from open databases such OpenStreetMap reveals that although there have been exponential growth in the number of contributed POIs (Points of Interest), the lack of detailed attribute information is immediately visible. The process of adding attribute information to VGI databases is usually considered as a boring task and it is believed that contributors do not experience a similar level of satisfaction when they add such detailed information compared to tasks like adding new roads or copying building boundaries from satellite imageries. In other crowdsourcing projects, different approaches are taken for engaging contributors in problem solving by embedding the tasks inside a game. In the literature, this concept is known as "gamification" or "games with purpose" which encapsulate the idea of entertaining contributors while they are completing a particular defined task. Same concept is used to design a mobile application called "RoadPlex" which aims to collect general or specific attribute information for POIs The increased number of contributions in the past few months confirms that the design characteristics and the methodology of the game are appealing to players. Such growth enables us to evaluate the quality of the generated data through mining the database of answered questions. This paper reflects the some contribution results and emphasises the importance of using gamification concept in the domain of VGI.

The Whorfian time warp: Representing duration through the language hourglass.

PubMed

Bylund, Emanuel; Athanasopoulos, Panos

2017-07-01

How do humans construct their mental representations of the passage of time? The universalist account claims that abstract concepts like time are universal across humans. In contrast, the linguistic relativity hypothesis holds that speakers of different languages represent duration differently. The precise impact of language on duration representation is, however, unknown. Here, we show that language can have a powerful role in transforming humans' psychophysical experience of time. Contrary to the universalist account, we found language-specific interference in a duration reproduction task, where stimulus duration conflicted with its physical growth. When reproducing duration, Swedish speakers were misled by stimulus length, and Spanish speakers were misled by stimulus size/quantity. These patterns conform to preferred expressions of duration magnitude in these languages (Swedish: long/short time; Spanish: much/small time). Critically, Spanish-Swedish bilinguals performing the task in both languages showed different interference depending on language context. Such shifting behavior within the same individual reveals hitherto undocumented levels of flexibility in time representation. Finally, contrary to the linguistic relativity hypothesis, language interference was confined to difficult discriminations (i.e., when stimuli varied only subtly in duration and growth), and was eliminated when linguistic cues were removed from the task. These results reveal the malleable nature of human time representation as part of a highly adaptive information processing system. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Transcriptional, translational, and physiological signatures of undernourished honey bees (Apis mellifera) suggest a role for hormonal factors in hypopharyngeal gland degradation.

PubMed

Corby-Harris, Vanessa; Meador, Charlotte A D; Snyder, Lucy A; Schwan, Melissa R; Maes, Patrick; Jones, Beryl M; Walton, Alexander; Anderson, Kirk E

2016-02-01

Honey bee colonies function as a superorganism, where facultatively sterile female workers perform various tasks that support the hive. Nurse workers undergo numerous anatomical and physiological changes in preparation for brood rearing, including the growth of hypopharyngeal glands (HGs). These glands produce the major protein fraction of a protein- and lipid-rich jelly used to sustain developing larvae. Pollen intake is positively correlated with HG growth, but growth in the first three days is similar regardless of diet, suggesting that initial growth is a pre-determined process while later HG development depends on nutrient availability during a critical window in early adulthood (>3 d). It is unclear whether the resultant size differences in nurse HG are simply due to growth arrest or active degradation of the tissue. To determine what processes cause such differences in HG size, we catalogued the differential expression of both gene transcripts and proteins in the HGs of 8 d old bees that were fed diets containing pollen or no pollen. 3438 genes and 367 proteins were differentially regulated due to nutrition. Of the genes and proteins differentially expressed, undernourished bees exhibited more gene and protein up-regulation compared to well-nourished bees, with the affected processes including salivary gland apoptosis, oogenesis, and hormone signaling. Protein secretion was virtually the only process up-regulated in well-nourished bees. Further assays demonstrated that inhibition of ultraspiracle, one component of the ecdysteroid receptor, in the fat body caused larger HGs. Undernourished bees also had higher acid phosphatase activity, a physiological marker of cell death, compared to well-nourished bees. These results support a connection between poor nutrition, hormonal signaling, and HG degradation. Published by Elsevier Ltd.

The interaction between specific and general information in category learning and representation: unitization and parallel interactive processing.

PubMed

Nahinsky, Irwin D; Harbison, J Isaiah

2011-01-01

We investigated the effects of specific stimulus information on the use of rule information in a category learning task in 2 experiments, one presented here and an intercategory transfer task reported in an earlier article. In the present experiment photograph--name combinations, called identifiers, were associated with 4 demographic attributes. The same attribute information was shown to all participants. However, for one group of participants, half of the identifiers were paired with attribute values repeated over presentation blocks. For the other group the identifier information was new for each presentation block. The first group performed less well than the second group on stimuli with nonrepeated identifiers, indicating a negative effect of specific stimulus information on processing rule information. Application of a network model to the 2 experiments, which provided for the growth of connections between attribute values in learning, indicated that repetition of identifiers produced a unitizing effect on stimuli. Results suggested that unitization produced interference through connections between irrelevant attribute values.

Development and Evaluation of Die Materials for Use in the Growth of Silicon Ribbons by the Inverted Ribbon Growth Process. Task 2: LSSA Project

NASA Technical Reports Server (NTRS)

Duffy, M. T.; Berkman, S.; Moss, H. I.; Cullen, G. W.

1978-01-01

Several ribbon growth experiments were performed from V-shaped dies coated with CVD Si3N4. The most significant result was the ability to perform five consecutive growth runs from the same die without mechanical degradation of the die through temperature cycling. The die was made from vitreous carbon coated with CVD Si3N4. Silicon oxynitride, Si2N2O, was examined with respect to thermal stability in contact with molten silicon. The results of X-ray analysis indicate that this material is converted to both alpha - and beta-Si3N4 in the presence of molten silicon. Experiments on the stability of CVD SiOxNy shoe that this material can be maintained in contact with molten silicon (sessile drop test) for greater than 30 h at 1450 C without total decompositon. These layers are converted mainly to beta-Si3N4.

High-Fidelity 3D-Nanoprinting via Focused Electron Beams: Growth Fundamentals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkler, Robert; Lewis, Brett B.; Fowlkes, Jason Davidson

While 3D-printing is currently experiencing significant growth and having a significant impact on science and technology, the expansion into the nanoworld is still a highly challenging task. Among the increasing number of approaches, focused electron-beam-induced deposition (FEBID) was recently demonstrated to be a viable candidate toward a generic direct-write fabrication technology with spatial nanometer accuracy for complex shaped 3D-nanoarchitectures. In this comprehensive study, we explore the parameter space for 3D-FEBID and investigate the implications of individual and interdependent parameters on freestanding nanosegments, which act as a fundamental building block for complex 3D-structures. In particular, the study provides new basic insightsmore » such as precursor transport limitations and angle dependent growth rates, both essential for high-fidelity fabrication. In conclusion, complemented by practical aspects, we provide both basic insights in 3D-growth dynamics and technical guidance for specific process adaption to enable predictable and reliable direct-write synthesis of freestanding 3D-nanoarchitectures.« less

High-Fidelity 3D-Nanoprinting via Focused Electron Beams: Growth Fundamentals

DOE PAGES

Winkler, Robert; Lewis, Brett B.; Fowlkes, Jason Davidson; ...

2018-02-14

While 3D-printing is currently experiencing significant growth and having a significant impact on science and technology, the expansion into the nanoworld is still a highly challenging task. Among the increasing number of approaches, focused electron-beam-induced deposition (FEBID) was recently demonstrated to be a viable candidate toward a generic direct-write fabrication technology with spatial nanometer accuracy for complex shaped 3D-nanoarchitectures. In this comprehensive study, we explore the parameter space for 3D-FEBID and investigate the implications of individual and interdependent parameters on freestanding nanosegments, which act as a fundamental building block for complex 3D-structures. In particular, the study provides new basic insightsmore » such as precursor transport limitations and angle dependent growth rates, both essential for high-fidelity fabrication. In conclusion, complemented by practical aspects, we provide both basic insights in 3D-growth dynamics and technical guidance for specific process adaption to enable predictable and reliable direct-write synthesis of freestanding 3D-nanoarchitectures.« less

Do Growth Mindsets in Math Benefit Females? Identifying Pathways between Gender, Mindset, and Motivation.

PubMed

Degol, Jessica L; Wang, Ming-Te; Zhang, Ya; Allerton, Julie

2018-05-01

Despite efforts to increase female representation in science, technology, engineering, and mathematics (STEM), females continue to be less motivated to pursue STEM careers than males. A short-term longitudinal study used a sample of 1449 high school students (grades 9-12; 49% females) to examine pathways from gender and mindset onto STEM outcomes via motivational beliefs (i.e., expectancy beliefs, task value, and cost). Mindset, motivational beliefs, and STEM career aspirations were assessed between the fall and winter months of the 2014-2015 school year and math grades were obtained at the conclusion of the same year. Student growth mindset beliefs predicted higher task values in math. Task values also mediated the pathway from a growth mindset to higher STEM career aspirations. Expectancy beliefs mediated the pathway between gender and math achievement. This mediated pathway was stronger for females than for males, such that females had higher math achievement than males when they endorsed a growth mindset. Findings suggest possible avenues for improving female's interest in STEM.

Mobil Solar Energy Corporation thin EFG octagons

NASA Astrophysics Data System (ADS)

Kalejs, J. P.

1994-06-01

Mobil Solar Energy Corporation manufactures photovoltaic modules based on its unique Edge-defined Film-fed Growth (EFG) process for producing octagon-shaped hollow polycrystalline silicon tubes. The octagons are cut by lasers into 100 mm x 100 mm wafers which are suitable for solar cell processing. This process avoids slicing, grinding and polishing operations which are wasteful of material and are typical of most other wafer production methods. EFG wafers are fabricated into solar cells and modules using processes that have been specially developed to allow scaling up to high throughput rates. The goals of the Photovoltaic Manufacturing Technology Initiative (PVMaT) program at Mobil Solar were to improve the EFG manufacturing line through technology advances that accelerate cost reduction in production and stimulate market growth for its product. The program was structured into three main tasks: to decrease silicon utilization by lowering wafer thickness from 400 to 200 (mu)m; to enhance laser cutting yields and throughput while improving the wafer strength; and to raise crystal growth productivity and yield. The technical problems faced and the advances made in the Mobil Solar PVMaT program are described. The author concludes with a presentation of the results of a detailed cost model for EFT module production. This model describes the accelerated reductions in manufacturing costs which are already in place and the future benefits anticipated to result from the technical achievements of the PVMaT program.

On the costs of parallel processing in dual-task performance: The case of lexical processing in word production.

PubMed

Paucke, Madlen; Oppermann, Frank; Koch, Iring; Jescheniak, Jörg D

2015-12-01

Previous dual-task picture-naming studies suggest that lexical processes require capacity-limited processes and prevent other tasks to be carried out in parallel. However, studies involving the processing of multiple pictures suggest that parallel lexical processing is possible. The present study investigated the specific costs that may arise when such parallel processing occurs. We used a novel dual-task paradigm by presenting 2 visual objects associated with different tasks and manipulating between-task similarity. With high similarity, a picture-naming task (T1) was combined with a phoneme-decision task (T2), so that lexical processes were shared across tasks. With low similarity, picture-naming was combined with a size-decision T2 (nonshared lexical processes). In Experiment 1, we found that a manipulation of lexical processes (lexical frequency of T1 object name) showed an additive propagation with low between-task similarity and an overadditive propagation with high between-task similarity. Experiment 2 replicated this differential forward propagation of the lexical effect and showed that it disappeared with longer stimulus onset asynchronies. Moreover, both experiments showed backward crosstalk, indexed as worse T1 performance with high between-task similarity compared with low similarity. Together, these findings suggest that conditions of high between-task similarity can lead to parallel lexical processing in both tasks, which, however, does not result in benefits but rather in extra performance costs. These costs can be attributed to crosstalk based on the dual-task binding problem arising from parallel processing. Hence, the present study reveals that capacity-limited lexical processing can run in parallel across dual tasks but only at the expense of extraordinary high costs. (c) 2015 APA, all rights reserved).

Low cost silicon solar array project large area silicon sheet task: Silicon web process development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Blais, P. D.; Davis, J. R., Jr.

1977-01-01

Growth configurations were developed which produced crystals having low residual stress levels. The properties of a 106 mm diameter round crucible were evaluated and it was found that this design had greatly enhanced temperature fluctuations arising from convection in the melt. Thermal modeling efforts were directed to developing finite element models of the 106 mm round crucible and an elongated susceptor/crucible configuration. Also, the thermal model for the heat loss modes from the dendritic web was examined for guidance in reducing the thermal stress in the web. An economic analysis was prepared to evaluate the silicon web process in relation to price goals.

High Quality, Low Cost Bulk Gallium Nitride Substrates Grown by the Electrochemical Solution Growth Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seacrist, Michael

The objective of this project was to develop the Electrochemical Solution Growth (ESG) method conceived / patented at Sandia National Laboratory into a commercially viable bulk gallium nitride (GaN) growth process that can be scaled to low cost, high quality, and large area GaN wafer substrate manufacturing. The goal was to advance the ESG growth technology by demonstrating rotating seed growth at the lab scale and then transitioning process to prototype commercial system, while validating the GaN material and electronic / optical device quality. The desired outcome of the project is a prototype commercial process for US-based manufacturing of highmore » quality, large area, and lower cost GaN substrates that can drive widespread deployment of energy efficient GaN-based power electronic and optical devices. In year 1 of the project (Sept 2012 – Dec 2013) the overall objective was to demonstrate crystalline GaN growth > 100um on a GaN seed crystal. The development plan included tasks to demonstrate and implement a method for purifying reagent grade salts, develop the reactor 1 process for rotating seed Electrochemical Solution Growth (ESG) of GaN, grow and characterize ESG GaN films, develop a fluid flow and reaction chemistry model for GaN film growth, and design / build an improved growth reactor capable of scaling to 50mm seed diameter. The first year’s project objectives were met in some task areas including salt purification, film characterization, modeling, and reactor 2 design / fabrication. However, the key project objective of the growth of a crystalline GaN film on the seed template was not achieved. Amorphous film growth on the order of a few tenths of a micron has been detected with a film composition including Ga and N, plus several other impurities originating from the process solution and hardware. The presence of these impurities, particularly the oxygen, has inhibited the demonstration of crystalline GaN film growth on the seed template. However, the presence of both Ga and N at the growth surface indicates that the reactor hardware physics is all functioning properly; achieving film growth is a matter of controlling the chemistry at the interface. The impurities originating from the hardware are expected to be straightforward to eliminate. Activities were defined for an extension of budget period 1 to eliminate the undesired impurities originating from the reactor hardware and interfering with crystalline GaN film growth. The budget period 1 extension was negotiated during the 1st half of 2014. The budget period 1 extension spanned approximately from August 2014 to August 2015. The project objective for this extension period was to demonstrate at least 0.5um crystalline GaN film on a GaN seed in the lab scale reactor. The focus of the budget 1 extension period from August 2014 to August 2015 was to eliminate oxygen contamination interference with GaN film growth. The team procured the highest purity lowest oxygen salt for testing. Low oxygen crucible materials such as silicon carbide were installed and evaluated in the laboratory reactor. Growth experiments were performed with high purity salt, high purity hardware, and optimized oxide removal from the seed surface. Experiments were characterized with methods including UV inspection, profilometry, x-ray diffraction (XRD) to determine crystalline structure, optical and scanning electron microscopy, photoluminescence, x-ray photon spectroscopy (XPS), transmission electron microscopy (TEM), and secondary ion mass spectroscopy (SIMS). Despite successfully integrating the low oxygen materials in the laboratory reactor, the goal of depositing 0.5um of crystalline GaN on the MOCVD GaN seed was not met. Very thin (ca. 10nm) cubic phase GaN deposition was observed on the hexagonal MOCVD GaN seeds. But there was a competing etching reaction which was also observed and thought to be related to the presence of metallic lithium, a byproduct of the LiCl-KCl salt used as the process medium. The etching reaction could potentially be addressed by alternate salts not containing lithium, but would necessitate starting all over on the reactor and process design. Further, controlling the reaction of Ga and N in the bulk salt to favor deposition on the seed has proved to be very difficult and unlikely to be solved within the scope of this project in a manner consistent with the original objective for wafer or crystal scale thickness for GaN deposition on a GaN seed. Upon completion of the budget 1 extension period in August 2015 the project partners and DOE agreed to stop work on the project.« less

Cloud Based Metalearning System for Predictive Modeling of Biomedical Data

PubMed Central

Vukićević, Milan

2014-01-01

Rapid growth and storage of biomedical data enabled many opportunities for predictive modeling and improvement of healthcare processes. On the other side analysis of such large amounts of data is a difficult and computationally intensive task for most existing data mining algorithms. This problem is addressed by proposing a cloud based system that integrates metalearning framework for ranking and selection of best predictive algorithms for data at hand and open source big data technologies for analysis of biomedical data. PMID:24892101

Microgravity sciences application visiting scientist program

NASA Technical Reports Server (NTRS)

Glicksman, Martin; Vanalstine, James

1995-01-01

Marshall Space Flight Center pursues scientific research in the area of low-gravity effects on materials and processes. To facilitate these Government performed research responsibilities, a number of supplementary research tasks were accomplished by a group of specialized visiting scientists. They participated in work on contemporary research problems with specific objectives related to current or future space flight experiments and defined and established independent programs of research which were based on scientific peer review and the relevance of the defined research to NASA microgravity for implementing a portion of the national program. The programs included research in the following areas: protein crystal growth, X-ray crystallography and computer analysis of protein crystal structure, optimization and analysis of protein crystal growth techniques, and design and testing of flight hardware.

The changing global context of public health.

PubMed

McMichael, A J; Beaglehole, R

2000-08-05

Future health prospects depend increasingly on globalisation processes and on the impact of global environmental change. Economic globalisation--entailng deregulated trade and investment--is a mixed blessing for health. Economic growth and the dissemination of technologies have widely enhanced life expectancy. However, aspects of globalisation are jeopardising health by eroding social and environmental conditions, exacerbating the rich-poor gap, and disseminating consumerism. Global environmental changes reflect the growth of populations and the intensity of economic activity. These changes include altered composition of the atmosphere, land degradation, depletion of terrestrial aquifers and ocean fisheries, and loss of biodiversity. This weakening of life-supporting systems poses health risks. Contemporary public health must therefore encompass the interrelated tasks of reducing social and health inequalities and achieving health-sustaining environments.

Personal growth initiative and identity formation in adolescence through young adulthood: mediating processes on the pathway to well-being.

PubMed

Luyckx, Koen; Robitschek, Christine

2014-10-01

Developing a personal identity is a challenging task throughout adolescence and the transition to adulthood. The present study sampling 551 14-35 year olds (54.1% female) examined personal growth initiative (PGI) as a potential predictor of core identity processes and explored whether identity functioned as a mediator on the pathway from PGI to self-esteem and depressive symptoms. Path analyses from a structural equation modeling approach indicated that all four components of PGI (i.e., planfulness, readiness for change, intentional behavior, and using resources) predicted different commitment and exploration processes, with planfulness being the most consistent predictor. Important age differences linking PGI-components to identity exploration were found. Finally, especially the degree to which individuals identified themselves with their identity commitments and the degree to which they relied on ruminative or maladaptive forms of identity exploration mediated pathways from PGI to self-esteem and depressive symptoms. Implications and suggestions for future research are discussed. Copyright © 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Advanced automation for in-space vehicle processing

NASA Technical Reports Server (NTRS)

Sklar, Michael; Wegerif, D.

1990-01-01

The primary objective of this 3-year planned study is to assure that the fully evolved Space Station Freedom (SSF) can support automated processing of exploratory mission vehicles. Current study assessments show that required extravehicular activity (EVA) and to some extent intravehicular activity (IVA) manpower requirements for required processing tasks far exceeds the available manpower. Furthermore, many processing tasks are either hazardous operations or they exceed EVA capability. Thus, automation is essential for SSF transportation node functionality. Here, advanced automation represents the replacement of human performed tasks beyond the planned baseline automated tasks. Both physical tasks such as manipulation, assembly and actuation, and cognitive tasks such as visual inspection, monitoring and diagnosis, and task planning are considered. During this first year of activity both the Phobos/Gateway Mars Expedition and Lunar Evolution missions proposed by the Office of Exploration have been evaluated. A methodology for choosing optimal tasks to be automated has been developed. Processing tasks for both missions have been ranked on the basis of automation potential. The underlying concept in evaluating and describing processing tasks has been the use of a common set of 'Primitive' task descriptions. Primitive or standard tasks have been developed both for manual or crew processing and automated machine processing.

A specific implicit sequence learning deficit as an underlying cause of dyslexia? Investigating the role of attention in implicit learning tasks.

PubMed

Staels, Eva; Van den Broeck, Wim

2017-05-01

Recently, a general implicit sequence learning deficit was proposed as an underlying cause of dyslexia. This new hypothesis was investigated in the present study by including a number of methodological improvements, for example, the inclusion of appropriate control conditions. The second goal of the study was to explore the role of attentional functioning in implicit and explicit learning tasks. In a 2 × 2 within-subjects design 4 tasks were administered in 30 dyslexic and 38 control children: an implicit and explicit serial reaction time (RT) task and an implicit and explicit contextual cueing task. Attentional functioning was also administered. The entire learning curves of all tasks were analyzed using latent growth curve modeling in order to compare performances between groups and to examine the role of attentional functioning on the learning curves. The amount of implicit learning was similar for both groups. However, the dyslexic group showed slower RTs throughout the entire task. This group difference reduced and became nonsignificant after controlling for attentional functioning. Both implicit learning tasks, but none of the explicit learning tasks, were significantly affected by attentional functioning. Dyslexic children do not suffer from a specific implicit sequence learning deficit. The slower RTs of the dyslexic children throughout the entire implicit sequence learning process are caused by their comorbid attention problems and overall slowness. A key finding of the present study is that, in contrast to what was assumed for a long time, implicit learning relies on attentional resources, perhaps even more than explicit learning does. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The source of dual-task limitations: Serial or parallel processing of multiple response selections?

PubMed Central

Marois, René

2014-01-01

Although it is generally recognized that the concurrent performance of two tasks incurs costs, the sources of these dual-task costs remain controversial. The serial bottleneck model suggests that serial postponement of task performance in dual-task conditions results from a central stage of response selection that can only process one task at a time. Cognitive-control models, by contrast, propose that multiple response selections can proceed in parallel, but that serial processing of task performance is predominantly adopted because its processing efficiency is higher than that of parallel processing. In the present study, we empirically tested this proposition by examining whether parallel processing would occur when it was more efficient and financially rewarded. The results indicated that even when parallel processing was more efficient and was incentivized by financial reward, participants still failed to process tasks in parallel. We conclude that central information processing is limited by a serial bottleneck. PMID:23864266

All varieties of encoding variability are not created equal: Separating variable processing from variable tasks

PubMed Central

Huff, Mark J.; Bodner, Glen E.

2014-01-01

Whether encoding variability facilitates memory is shown to depend on whether item-specific and relational processing are both performed across study blocks, and whether study items are weakly versus strongly related. Variable-processing groups studied a word list once using an item-specific task and once using a relational task. Variable-task groups’ two different study tasks recruited the same type of processing each block. Repeated-task groups performed the same study task each block. Recall and recognition were greatest in the variable-processing group, but only with weakly related lists. A variable-processing benefit was also found when task-based processing and list-type processing were complementary (e.g., item-specific processing of a related list) rather than redundant (e.g., relational processing of a related list). That performing both item-specific and relational processing across trials, or within a trial, yields encoding-variability benefits may help reconcile decades of contradictory findings in this area. PMID:25018583

Flexible and inflexible task sets: asymmetric interference when switching between emotional expression, sex, and age classification of perceived faces.

PubMed

Schuch, Stefanie; Werheid, Katja; Koch, Iring

2012-01-01

The present study investigated whether the processing characteristics of categorizing emotional facial expressions are different from those of categorizing facial age and sex information. Given that emotions change rapidly, it was hypothesized that processing facial expressions involves a more flexible task set that causes less between-task interference than the task sets involved in processing age or sex of a face. Participants switched between three tasks: categorizing a face as looking happy or angry (emotion task), young or old (age task), and male or female (sex task). Interference between tasks was measured by global interference and response interference. Both measures revealed patterns of asymmetric interference. Global between-task interference was reduced when a task was mixed with the emotion task. Response interference, as measured by congruency effects, was larger for the emotion task than for the nonemotional tasks. The results support the idea that processing emotional facial expression constitutes a more flexible task set that causes less interference (i.e., task-set "inertia") than processing the age or sex of a face.

When Challenging Art Gets Liked: Evidences for a Dual Preference Formation Process for Fluent and Non-Fluent Portraits

PubMed Central

Belke, Benno; Leder, Helmut; Carbon, Claus Christian

2015-01-01

Although fluency theory predominates psychological research on human aesthetics, its most severe limitation may be to explain why art that challenges or even violates easy processing can nevertheless be aesthetically rewarding. We discuss long-standing notions on art’s potential to offer mental growth opportunities and to tap into a basic epistemic predisposition that hint at a fluency counteracting aesthetic pleasure mechanism. Based on divergent strands of literature on empirical, evolutionary, and philosophical aesthetics, as well as research on disfluency, we presumed that challenging art requires deliberate reflexive processing at the level of “aboutness” in order to be experientially pleasing. Here, we probed such a cognitive mastering mechanism, achieved by iterative cycles of elaboration, as predicted by our model of aesthetic experiences. For the study, two kinds of portraits were applied, one associable to a high fluency and one to a high stimulation potential (according to results of an extensive rating study). In Experiment 1, we provided a repeated evaluation task, which revealed a distinctive preference effect for challenging portraits that was absent in the visual exposition conditions of a familiarity and a mere exposure task (Experiment 2). In a follow-up task (Experiment 3) this preference effect was observed with a novel and more encompassing pool of portraits, which corroborated its stability and robustness. In an explorative stimulus-transfer task (Experiment 4), we investigated the presumed underlying mechanism by testing whether the observed effect would generalize onto novel portraits of the same artist-specific styles. Results discounted an alternative interpretation of a perceptual adaptation effect and hinted at meaning-driven mental activity. Conjointly, findings for inexperienced viewers were indicative of an elaboration based mastering mechanism that selectively operated for mentally challenging portraits. Moreover, findings were in line with a dual-process view of human preference formation with art. Theoretical implications and boundary conditions are discussed. PMID:26309095

When Challenging Art Gets Liked: Evidences for a Dual Preference Formation Process for Fluent and Non-Fluent Portraits.

PubMed

Belke, Benno; Leder, Helmut; Carbon, Claus-Christian

2015-01-01

Although fluency theory predominates psychological research on human aesthetics, its most severe limitation may be to explain why art that challenges or even violates easy processing can nevertheless be aesthetically rewarding. We discuss long-standing notions on art's potential to offer mental growth opportunities and to tap into a basic epistemic predisposition that hint at a fluency counteracting aesthetic pleasure mechanism. Based on divergent strands of literature on empirical, evolutionary, and philosophical aesthetics, as well as research on disfluency, we presumed that challenging art requires deliberate reflexive processing at the level of "aboutness" in order to be experientially pleasing. Here, we probed such a cognitive mastering mechanism, achieved by iterative cycles of elaboration, as predicted by our model of aesthetic experiences. For the study, two kinds of portraits were applied, one associable to a high fluency and one to a high stimulation potential (according to results of an extensive rating study). In Experiment 1, we provided a repeated evaluation task, which revealed a distinctive preference effect for challenging portraits that was absent in the visual exposition conditions of a familiarity and a mere exposure task (Experiment 2). In a follow-up task (Experiment 3) this preference effect was observed with a novel and more encompassing pool of portraits, which corroborated its stability and robustness. In an explorative stimulus-transfer task (Experiment 4), we investigated the presumed underlying mechanism by testing whether the observed effect would generalize onto novel portraits of the same artist-specific styles. Results discounted an alternative interpretation of a perceptual adaptation effect and hinted at meaning-driven mental activity. Conjointly, findings for inexperienced viewers were indicative of an elaboration based mastering mechanism that selectively operated for mentally challenging portraits. Moreover, findings were in line with a dual-process view of human preference formation with art. Theoretical implications and boundary conditions are discussed.

Review of Canadian mobile satellite systems institutional arrangements policy

NASA Technical Reports Server (NTRS)

Gilvary, David

1990-01-01

Development of institutional arrangements policy for maritime, land, and aeronautical mobile satellite systems (MSS) is an integral part of the Canadian telecommunications policy process. An ongoing activity in that process is fitting of MSS institutional arrangements policy within the confines of the 1987 Canadian Telecom Policy Framework. Making sure the fit is correct is a major task at present because technology seems to be driving service demand at rapid growth rates, particularly in the case of land MSS. This growth is stimulating policy and regulatory development efforts to keep pace. In Canada, this is happening in four planned MSS applications areas: Canada-US transborder (immediate), aeronautical MSS (1990/94), Telesat Mobile Inc. EMDS via INMARSAT (1990), and MSAT (1993/94). The need for an up-to-date MSS policy in these areas is emphasized by related developments in the US and elsewhere. It arises because of the growing number of market initiatives proposing North American rather than Canada-only or US-only coverage, such as INMARSAT, Geostar, OmniTRACS, and Starlink.

A Longitudinal Study of Lexical Development in Children Learning Vietnamese and English

PubMed Central

Pham, Giang; Kohnert, Kathryn

2013-01-01

This longitudinal study modeled lexical development among children who spoke Vietnamese as a first language (L1) and English as a second language (L2). Participants (n=33, initial mean age of 7.3 years) completed a total of eight tasks (four in each language) that measured vocabulary knowledge and lexical processing at four yearly time points. Multivariate hierarchical linear modeling was used to calculate L1 and L2 trajectories within the same model for each task. Main findings included (a) positive growth in each language, (b) greater gains in English resulting in shifts toward L2 dominance, and (c) different patterns for receptive and expressive domains. Timing of shifts to L2 dominance underscored L1 skills that are resilient and vulnerable to increases in L2 proficiency. PMID:23869741

Bidirectional Relations between Phonological Awareness and Letter Knowledge in Preschool Revisited: A Growth Curve Analysis of the Relation between Two Code-Related Skills

PubMed Central

Lerner, Matthew D.; Lonigan, Christopher J.

2017-01-01

Despite the importance of phonological awareness for the development of reading in alphabetic languages, little attention has been paid to its developmental origins. In this study, dual-process, latent growth models were used to examine patterns of bidirectional relations between letter knowledge and phonological awareness during preschool. The sample comprised 358 children (mean age = 48.60 months, SD = 7.26). Growth models were used to quantify the unique longitudinal relations between the initial level of each skill and growth in the other skill during the preschool year, after controlling for initial level of the same skill, vocabulary, age, and growth in the code-related skill being used as a predictor. Letter-name knowledge and phonological awareness were bi-directionally related; the initial level of each uniquely predicted growth in the other. Initial letter-sound knowledge and phonological awareness growth were not uniquely related, and vocabulary was not related to growth in phonological awareness. These findings extend the evidence of the relation between letter knowledge and phonological awareness to supra-phonemic tasks, indicating that this bidirectional relation begins at an earlier point in the development of phonological awareness than previously reported. In addition, these findings help to rule out general growth in letter knowledge and phonological awareness as an alternative explanation for the bidirectional relation between these two code-related skills. PMID:26745710

Professional Development for Mathematics Teachers: Using Task Design and Analysis

ERIC Educational Resources Information Center

Lee, Hea-Jin; Özgün-Koca, S. Asli

2016-01-01

This study is based on a Task Design and Analysis activity from a year-long professional development program. The activity was designed to increase teacher growth in several areas, including knowledge of mathematics, understanding of students' cognitive activity, knowledge of good questions, and ability to develop and improve high quality tasks.…

The effects of bilingual growth on toddlers’ executive function

PubMed Central

Crivello, Cristina; Kuzyk, Olivia; Rodrigues, Monyka; Friend, Margaret; Zesiger, Pascal; Poulin-Dubois, Diane

2015-01-01

The mastery of two languages provides bilingual speakers with cognitive benefits over monolinguals, particularly on cognitive flexibility and selective attention. However, extant research is limited to comparisons between monolinguals and bilinguals at a single point in time. This study investigated whether growth in bilingual proficiency, as shown by an increased number of translation equivalents (TEs) over a 7-month period, improves executive function. We hypothesized that bilingual toddlers with a larger increase of TEs would have more practice in switching across lexical systems, boosting executive function abilities. Expressive vocabulary and TEs were assessed at 24 and 31 months of age. A battery of tasks, including conflict, delay, and working memory tasks, was administered at 31 months. As expected, we observed a task-specific advantage in inhibitory control in bilinguals. More important, within the bilingual group, larger increases in the number of TEs predicted better performance on conflict tasks but not on delay tasks. This unique longitudinal design confirms the relation between executive function and early bilingualism. PMID:26402219

Large-area sheet task advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.

1983-01-01

Modeling in the development of low stress configurations for wide web growth is presented. Parametric sensitivity to identify design features which can be used for dynamic trimming of the furnace element was studied. Temperature measurements of experimental growth behavior led to modification in the growth system to improve lateral temperature distributions.

Mobil Solar Energy Corporation thin EFG octagons. Final subcontract report, 1 April 1992--31 January 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalejs, J.P.

1994-06-01

Mobil Solar Energy Corporation manufactures photovoltaic modules based on its unique Edge-defined Film-fed Growth (EFG) process for producing octagon-shaped hollow polycrystalline silicon tubes. The octagons are cut by lasers into 100 mm x 100 mm wafers which are suitable for solar cell processing. This process avoids slicing, grinding and polishing operations which are wasteful of material and are typical of most other wafer production methods. EFG wafers are fabricated into solar cells and modules using processes that have been specially developed to allow scaling up to high throughput rates. The goals of the Photovoltaic Manufacturing Technology Initiative (PVMaT) program atmore » Mobil Solar were to improve the EFG manufacturing line through technology advances that accelerate cost reduction in production and stimulate market growth for its product. The program was structured into three main tasks: to decrease silicon utilization by lowering wafer thickness from 400 to 200 {mu}m; to enhance laser cutting yields and throughput while improving the wafer strength; and to raise crystal growth productivity and yield. The technical problems faced and the advances made in the Mobil Solar PVMaT program are described. The author concludes with a presentation of the results of a detailed cost model for EFT module production. This model describes the accelerated reductions in manufacturing costs which are already in place and the future benefits anticipated to result from the technical achievements of the PVMaT program.« less

A study of crystal growth by solution technique

NASA Technical Reports Server (NTRS)

Lal, R. B.

1981-01-01

The mechanism of crystal growth by solution technique was studied. A low temperature solution crystal growth setup was developed. Crystals of triglycine sulfate (TGS) were grown using this arrangement. Some additional tasks were performed toward fabrication of experiments for future space flight.

An Integrated Decision-Making Model for Categorizing Weather Products and Decision Aids

NASA Technical Reports Server (NTRS)

Elgin, Peter D.; Thomas, Rickey P.

2004-01-01

The National Airspace System s capacity will experience considerable growth in the next few decades. Weather adversely affects safe air travel. The FAA and NASA are working to develop new technologies that display weather information to support situation awareness and optimize pilot decision-making in avoiding hazardous weather. Understanding situation awareness and naturalistic decision-making is an important step in achieving this goal. Information representation and situation time stress greatly influence attentional resource allocation and working memory capacity, potentially obstructing accurate situation awareness assessments. Three naturalistic decision-making theories were integrated to provide an understanding of the levels of decision making incorporated in three operational situations and two conditions. The task characteristics associated with each phase of flight govern the level of situation awareness attained and the decision making processes utilized. Weather product s attributes and situation task characteristics combine to classify weather products according to the decision-making processes best supported. In addition, a graphical interface is described that affords intuitive selection of the appropriate weather product relative to the pilot s current flight situation.

Development and evaluation of die materials for use in the growth of silicon ribbons by the inverted ribbon growth process, task 2. LSSA project

NASA Technical Reports Server (NTRS)

Duffy, M. T.; Berkman, S.; Moss, H. S.; Cullen, G. W.

1978-01-01

The results of emission spectroscopic analysis indicate that molten silicon can remain in contact with hot-pressed Si3N4 (99.2 percent theoretical density) for prolonged periods without attaining the impurity content level of the nitride. Although MgO was used as binder, Mg was not found present in the silicon sessile drop in quantities much above the level initially present in the silicon source material. Preliminary experiments with EFG-type dies coated with CVD Si3N4 or CVD SiOxNy indicate that capillary rise does not occur readily in these dies. The same was found to be true of hot-pressed and reaction-sintered Si3N4 obtained commercially. However, when dies were formed by depositing CVD layers on shaped silicon slabs, a column of molten silicon was maintained in each CVD die while being heated in contact with a crucible of molten silicon. Preliminary wetting of dies appears necessary for EFG growth. Several ribbon growth experiments were performed from V-shaped dies.

Continuous Czochralski growth: Silicon sheet growth development of the large area silicon sheet task of the Low Cost Silicon Solar Array project

NASA Technical Reports Server (NTRS)

1978-01-01

The primary objective of this contract is to develop equipment and methods for the economic production of single crystal ingot material by the continuous Czochralski (CZ) process. Continuous CZ is defined for the purpose of this work as the growth of at least 100 kilograms of ingot from only one melt container. During the reporting period (October, 1977 - September, 1978), a modified grower was made fully functional and several recharge runs were performed. The largest run lasted 44 hours and over 42 kg of ingot was produced. Little, if any, degradation in efficiency was observed as a result of pulling multiple crystals from one crucible. Solar efficiencies observed were between 9.3 and 10.4% AMO (13.0 and 14.6% AMI) compared to 10.5% (14.7% AMI) for optimum CZ material control samples. Using the SAMICS/IPEG format, economic analysis of continuous CZ suggests that 1986 DoE cost goals can only be met by the growth of large diameter, large mass crystals.

Sodium Flux Growth of Bulk Gallium Nitride

NASA Astrophysics Data System (ADS)

Von Dollen, Paul Martin

This dissertation focused on development of a novel apparatus and techniques for crystal growth of bulk gallium nitride (GaN) using the sodium flux method. Though several methods exist to produce bulk GaN, none have been commercialized on an industrial scale. The sodium flux method offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. But the current equipment and methods for sodium flux growth of bulk GaN are generally not amenable to large-scale crystal growth or in situ investigation of growth processes, which has hampered progress. A key task was to prevent sodium loss or migration from the sodium-gallium growth melt while permitting N2 gas to access the growing crystal, which was accomplished by implementing a reflux condensing stem along with a reusable sealed capsule. The reflux condensing stem also enabled direct monitoring and control of the melt temperature, which has not been previously reported for the sodium flux method. Molybdenum-based materials were identified from a corrosion study as candidates for direct containment of the corrosive sodium-gallium melt. Successful introduction of these materials allowed implementation of a crucible-free containment system, which improved process control and can potentially reduce crystal impurity levels. Using the new growth system, the (0001) Ga face (+c plane) growth rate was >50 mum/hr, which is the highest bulk GaN growth rate reported for the sodium flux method. Omega X-ray rocking curve (?-XRC) measurements indicated the presence of multiple grains, though full width at half maximum (FWHM) values for individual peaks were <100 arcseconds. Oxygen impurity concentrations as measured by secondary ion mass spectroscopy (SIMS) were >1020 atoms/cm3, possibly due to reactor cleaning and handling procedures. This dissertation also introduced an in situ technique to correlate changes in N2 pressure with dissolution of nitrogen and precipitation of GaN from the sodium-gallium melt. Different stages of N2 pressure decay were identified and linked to distinct modes of GaN crystal growth. Based on this analysis, the highest growth rate may have up to 90 mum/hr, and did not appear to be mass-transport limited, in contrast to previous reports. Several refinements and improvements of the novel equipment and methods introduced were also explored, all of which have potential to further advance state of the art sodium flux growth of bulk GaN.

A comparison of transfer-appropriate processing and multi-process frameworks for prospective memory performance.

PubMed

McBride, Dawn M; Abney, Drew H

2012-01-01

We examined multi-process (MP) and transfer-appropriate processing descriptions of prospective memory (PM). Three conditions were compared that varied the overlap in processing type (perceptual/conceptual) between the ongoing and PM tasks such that two conditions involved a match of perceptual processing and one condition involved a mismatch in processing (conceptual ongoing task/perceptual PM task). One of the matched processing conditions also created a focal PM task, whereas the other two conditions were considered non-focal (Einstein & McDaniel, 2005). PM task accuracy and ongoing task completion speed in baseline and PM task conditions were measured. Accuracy results indicated a higher PM task completion rate for the focal condition than the non-focal conditions, a finding that is consistent with predictions made by the MP view. However, reaction time (RT) analyses indicated that PM task cost did not differ across conditions when practice effects are considered. Thus, the PM accuracy results are consistent with a MP description of PM, but RT results did not support the MP view predictions regarding PM cost.

Development of intelligent robots - Achievements and issues

NASA Astrophysics Data System (ADS)

Nitzan, D.

1985-03-01

A flexible, intelligent robot is regarded as a general purpose machine system that may include effectors, sensors, computers, and auxiliary equipment and, like a human, can perform a variety of tasks under unpredictable conditions. Development of intelligent robots is essential for increasing the growth rate of today's robot population in industry and elsewhere. Robotics research and development topics include manipulation, end effectors, mobility, sensing (noncontact and contact), adaptive control, robot programming languages, and manufacturing process planning. Past achievements and current issues related to each of these topics are described briefly.

Multimodality Tumor Delineation and Predictive Modelling via Fuzzy-Fusion Deformable Models and Biological Potential Functions

NASA Astrophysics Data System (ADS)

Wasserman, Richard Marc

The radiation therapy treatment planning (RTTP) process may be subdivided into three planning stages: gross tumor delineation, clinical target delineation, and modality dependent target definition. The research presented will focus on the first two planning tasks. A gross tumor target delineation methodology is proposed which focuses on the integration of MRI, CT, and PET imaging data towards the generation of a mathematically optimal tumor boundary. The solution to this problem is formulated within a framework integrating concepts from the fields of deformable modelling, region growing, fuzzy logic, and data fusion. The resulting fuzzy fusion algorithm can integrate both edge and region information from multiple medical modalities to delineate optimal regions of pathological tissue content. The subclinical boundaries of an infiltrating neoplasm cannot be determined explicitly via traditional imaging methods and are often defined to extend a fixed distance from the gross tumor boundary. In order to improve the clinical target definition process an estimation technique is proposed via which tumor growth may be modelled and subclinical growth predicted. An in vivo, macroscopic primary brain tumor growth model is presented, which may be fit to each patient undergoing treatment, allowing for the prediction of future growth and consequently the ability to estimate subclinical local invasion. Additionally, the patient specific in vivo tumor model will be of significant utility in multiple diagnostic clinical applications.

Efficient multitasking: parallel versus serial processing of multiple tasks

PubMed Central

Fischer, Rico; Plessow, Franziska

2015-01-01

In the context of performance optimizations in multitasking, a central debate has unfolded in multitasking research around whether cognitive processes related to different tasks proceed only sequentially (one at a time), or can operate in parallel (simultaneously). This review features a discussion of theoretical considerations and empirical evidence regarding parallel versus serial task processing in multitasking. In addition, we highlight how methodological differences and theoretical conceptions determine the extent to which parallel processing in multitasking can be detected, to guide their employment in future research. Parallel and serial processing of multiple tasks are not mutually exclusive. Therefore, questions focusing exclusively on either task-processing mode are too simplified. We review empirical evidence and demonstrate that shifting between more parallel and more serial task processing critically depends on the conditions under which multiple tasks are performed. We conclude that efficient multitasking is reflected by the ability of individuals to adjust multitasking performance to environmental demands by flexibly shifting between different processing strategies of multiple task-component scheduling. PMID:26441742

Efficient multitasking: parallel versus serial processing of multiple tasks.

PubMed

Fischer, Rico; Plessow, Franziska

2015-01-01

In the context of performance optimizations in multitasking, a central debate has unfolded in multitasking research around whether cognitive processes related to different tasks proceed only sequentially (one at a time), or can operate in parallel (simultaneously). This review features a discussion of theoretical considerations and empirical evidence regarding parallel versus serial task processing in multitasking. In addition, we highlight how methodological differences and theoretical conceptions determine the extent to which parallel processing in multitasking can be detected, to guide their employment in future research. Parallel and serial processing of multiple tasks are not mutually exclusive. Therefore, questions focusing exclusively on either task-processing mode are too simplified. We review empirical evidence and demonstrate that shifting between more parallel and more serial task processing critically depends on the conditions under which multiple tasks are performed. We conclude that efficient multitasking is reflected by the ability of individuals to adjust multitasking performance to environmental demands by flexibly shifting between different processing strategies of multiple task-component scheduling.

Measuring information processing in a client with extreme agitation following traumatic brain injury using the Perceive, Recall, Plan and Perform System of Task Analysis.

PubMed

Nott, Melissa T; Chapparo, Christine

2008-09-01

Agitation following traumatic brain injury is characterised by a heightened state of activity with disorganised information processing that interferes with learning and achieving functional goals. This study aimed to identify information processing problems during task performance of a severely agitated adult using the Perceive, Recall, Plan and Perform (PRPP) System of Task Analysis. Second, this study aimed to examine the sensitivity of the PRPP System to changes in task performance over a short period of rehabilitation, and third, to evaluate the guidance provided by the PRPP in directing intervention. A case study research design was employed. The PRPP System of Task Analysis was used to assess changes in task embedded information processing capacity during occupational therapy intervention with a severely agitated adult in a rehabilitation context. Performance is assessed on three selected tasks over a one-month period. Information processing difficulties during task performance can be clearly identified when observing a severely agitated adult following a traumatic brain injury. Processing skills involving attention, sensory processing and planning were most affected at this stage of rehabilitation. These processing difficulties are linked to established descriptions of agitated behaviour. Fluctuations in performance across three tasks of differing processing complexity were evident, leading to hypothesised relationships between task complexity, environment and novelty with information processing errors. Changes in specific information processing capacity over time were evident based on repeated measures using the PRPP System of Task Analysis. This lends preliminary support for its utility as an outcome measure, and raises hypotheses about the type of therapy required to enhance information processing in people with severe agitation. The PRPP System is sensitive to information processing changes in severely agitated adults when used to reassess performance over short intervals and can provide direct guidance to occupational therapy intervention to improve task embedded information processing by categorising errors under four stages of an information processing model: Perceive, Recall, Plan and Perform.

Development of hot and cool executive functions in middle childhood: Three-year growth curves of decision making and working memory updating.

PubMed

Lensing, Nele; Elsner, Birgit

2018-09-01

Although middle childhood is an important period for the development of hot and cool executive functions (EFs), longitudinal studies investigating trajectories of childhood EF development are still limited and little is known about predictors for individual developmental trajectories. The current study examined the development of two typical facets of cool and hot EFs over a 3-year period during middle childhood, comparing a younger cohort (6- and 7-year-olds at the first wave [T1]; n = 621) and an older cohort (8- and 9-year-olds at T1; n = 975) of children. "Cool" working memory updating (WM) was assessed using a backward digit span task, and "hot" decision making (DM) was assessed using a child variant of the Iowa Gambling Task. Linear latent growth curve analyses revealed evidence for developmental growth as well as interindividual variance in the initial level and rate of change in both EF facets. Initial level of WM was positively associated with age (both between and within cohorts), socioeconomic status, verbal ability, and processing speed, whereas initial levels of DM were, in addition to a (potentially age-related) cohort effect, exclusively predicted by gender, with boys outperforming girls. None of the variables predicted the rate of change, that is, the developmental trajectories. However, younger children, as compared with older children, had slightly steeper WM growth curves over time, hinting at a leveling off in the development of WM during middle childhood. In sum, these data add important evidence to the understanding of hot and cool EF development during middle childhood. Copyright © 2018 Elsevier Inc. All rights reserved.

Theoretical models for the regulation of DNA replication in fast-growing bacteria

NASA Astrophysics Data System (ADS)

Creutziger, Martin; Schmidt, Mischa; Lenz, Peter

2012-09-01

Growing in always changing environments, Escherichia coli cells are challenged by the task to coordinate growth and division. In particular, adaption of their growth program to the surrounding medium has to guarantee that the daughter cells obtain fully replicated chromosomes. Replication is therefore to be initiated at the right time, which is particularly challenging in media that support fast growth. Here, the mother cell initiates replication not only for the daughter but also for the granddaughter cells. This is possible only if replication occurs from several replication forks that all need to be correctly initiated. Despite considerable efforts during the last 40 years, regulation of this process is still unknown. Part of the difficulty arises from the fact that many details of the relevant molecular processes are not known. Here, we develop a novel theoretical strategy for dealing with this general problem: instead of analyzing a single model, we introduce a wide variety of 128 different models that make different assumptions about the unknown processes. By comparing the predictions of these models we are able to identify the key quantities that allow the experimental discrimination of the different models. Analysis of these quantities yields that out of the 128 models 94 are not consistent with available experimental data. From the remaining 34 models we are able to conclude that mass growth and DNA replication need either to be truly coupled, by coupling DNA replication initiation to the event of cell division, or to the amount of accumulated mass. Finally, we make suggestions for experiments to further reduce the number of possible regulation scenarios.

Empirical Support for 'Hastening-Through-Re-Automatization' by Contrasting Two Motor-Cognitive Dual Tasks.

PubMed

Langhanns, Christine; Müller, Hermann

2018-01-01

Motor-cognitive dual tasks have been intensely studied and it has been demonstrated that even well practiced movements like walking show signs of interference when performed concurrently with a challenging cognitive task. Typically walking speed is reduced, at least in elderly persons. In contrast to these findings, some authors report an increased movement frequency under dual-task conditions, which they call hastening . A tentative explanation has been proposed, assuming that the respective movements are governed by an automatic control regime. Though, under single-task conditions, these automatic processes are supervised by "higher-order" cognitive control processes. However, when a concurrent cognitive task binds all cognitive resources, the automatic process is freed from the detrimental effect of cognitive surveillance, allowing higher movement frequencies. Fast rhythmic movements (>1 Hz) should more likely be governed by such an automatic process than low frequency discrete repetitive movements. Fifteen subjects performed two repetitive movements under single and dual-task condition, that is, in combination with a mental calculation task. According to the expectations derived from the explanatory concept, we found an increased movement frequency under dual-task conditions only for the fast rhythmic movement (paddleball task) but not for the slower discrete repetitive task (pegboard task). fNIRS measurements of prefrontal cortical load confirmed the idea of an automatic processing in the paddleball task, whereas the pegboard task seems to be more controlled by processes interfering with the calculation related processing.

Empirical Support for ‘Hastening-Through-Re-Automatization’ by Contrasting Two Motor-Cognitive Dual Tasks

PubMed Central

Langhanns, Christine; Müller, Hermann

2018-01-01

Motor-cognitive dual tasks have been intensely studied and it has been demonstrated that even well practiced movements like walking show signs of interference when performed concurrently with a challenging cognitive task. Typically walking speed is reduced, at least in elderly persons. In contrast to these findings, some authors report an increased movement frequency under dual-task conditions, which they call hastening. A tentative explanation has been proposed, assuming that the respective movements are governed by an automatic control regime. Though, under single-task conditions, these automatic processes are supervised by “higher-order” cognitive control processes. However, when a concurrent cognitive task binds all cognitive resources, the automatic process is freed from the detrimental effect of cognitive surveillance, allowing higher movement frequencies. Fast rhythmic movements (>1 Hz) should more likely be governed by such an automatic process than low frequency discrete repetitive movements. Fifteen subjects performed two repetitive movements under single and dual-task condition, that is, in combination with a mental calculation task. According to the expectations derived from the explanatory concept, we found an increased movement frequency under dual-task conditions only for the fast rhythmic movement (paddleball task) but not for the slower discrete repetitive task (pegboard task). fNIRS measurements of prefrontal cortical load confirmed the idea of an automatic processing in the paddleball task, whereas the pegboard task seems to be more controlled by processes interfering with the calculation related processing. PMID:29887815

On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allendorf, Mark D.; Sopko, J.F.; Houf, William G.

2006-11-01

Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accuratemore » data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are reached concerning the factors affecting the growth rate in on-line APCVD reactors. In addition, a substantial body of data was generated that can be used to model many different industrial tin oxide coating processes. These data include the most extensive compilation of thermochemistry for gas-phase tin-containing species as well as kinetic expressions describing tin oxide growth rates over a wide range of temperatures, pressures, and reactant concentrations.« less

Electrophysiological evidence of automatic early semantic processing.

PubMed

Hinojosa, José A; Martín-Loeches, Manuel; Muñoz, Francisco; Casado, Pilar; Pozo, Miguel A

2004-01-01

This study investigates the automatic-controlled nature of early semantic processing by means of the Recognition Potential (RP), an event-related potential response that reflects lexical selection processes. For this purpose tasks differing in their processing requirements were used. Half of the participants performed a physical task involving a lower-upper case discrimination judgement (shallow processing requirements), whereas the other half carried out a semantic task, consisting in detecting animal names (deep processing requirements). Stimuli were identical in the two tasks. Reaction time measures revealed that the physical task was easier to perform than the semantic task. However, RP effects elicited by the physical and semantic tasks did not differ in either latency, amplitude, or topographic distribution. Thus, the results from the present study suggest that early semantic processing is automatically triggered whenever a linguistic stimulus enters the language processor.

The psychophysiology of parenting: Individual differences in autonomic reactivity to positive and negative mood inductions and observed parental affect during dyadic interactions with children.

PubMed

Connell, Arin M; Dawson, Glen C; Danzo, Sarah; McKillop, Hannah N

2017-02-01

Parenting is a complex activity driven, in part, by parental emotional and physiological responses. However, work examining the physiological underpinnings of parenting behavior is still in its infancy, and very few studies have examined such processes beyond early childhood. The current study examines associations between Autonomic Nervous System (ANS) indices of parents' physiological reactivity to positive and negative mood states and observed parental affect during a series of discussion tasks with their adolescent child. Respiratory Sinus Arrhythmia (RSA) was measured as an index of parasympathetic nervous system (PNS) activation while viewing film clips designed to induce neutral, sad, and amused mood states. Parental positive affect, anger, and distress were observed during a series of parent-child discussion tasks, which included an ambiguous discussion regarding adolescent growth, a conflict discussion, and a fun-activity planning discussion. Results supported the association between aspects of parental physiological reactivity and observed affect during dyadic interactions. Further, RSA interacted with maternal depression to predict observed positive affect, anger, and distress, although differences across tasks and specific emotions were found regarding the nature of the interaction effects. Overall, results suggest that such neurobiological processes may be particularly important predictors of parental behavior, particularly in at-risk populations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity.

PubMed

Künstler, E C S; Finke, K; Günther, A; Klingner, C; Witte, O; Bublak, P

2018-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the 'theory of visual attention' (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual short-term memory (VSTM) storage capacity. Moreover, goodness-of-fit values and bootstrapping estimates were derived to test whether the TVA-model is validly applicable also under dual task conditions, and whether the robustness of parameter estimates is comparable in single- and dual-task conditions. 24 subjects of middle to higher age performed a continuous tapping task, and a visual processing task (whole report of briefly presented letter arrays) under both single- and dual-task conditions. Results suggest a decline of both visual processing capacity and VSTM storage capacity under dual-task conditions, while the perceptual threshold remained unaffected by a concurrent motor task. In addition, goodness-of-fit values and bootstrapping estimates support the notion that participants processed the visual task in a qualitatively comparable, although quantitatively less efficient way under dual-task conditions. The results support a capacity sharing account of motor-cognitive dual tasking and suggest that even performing a relatively simple motor task relies on central attentional capacity that is necessary for efficient visual information uptake.

Predicting Future Reading Problems Based on Pre-reading Auditory Measures: A Longitudinal Study of Children with a Familial Risk of Dyslexia

PubMed Central

Law, Jeremy M.; Vandermosten, Maaike; Ghesquière, Pol; Wouters, Jan

2017-01-01

Purpose: This longitudinal study examines measures of temporal auditory processing in pre-reading children with a family risk of dyslexia. Specifically, it attempts to ascertain whether pre-reading auditory processing, speech perception, and phonological awareness (PA) reliably predict later literacy achievement. Additionally, this study retrospectively examines the presence of pre-reading auditory processing, speech perception, and PA impairments in children later found to be literacy impaired. Method: Forty-four pre-reading children with and without a family risk of dyslexia were assessed at three time points (kindergarten, first, and second grade). Auditory processing measures of rise time (RT) discrimination and frequency modulation (FM) along with speech perception, PA, and various literacy tasks were assessed. Results: Kindergarten RT uniquely contributed to growth in literacy in grades one and two, even after controlling for letter knowledge and PA. Highly significant concurrent and predictive correlations were observed with kindergarten RT significantly predicting first grade PA. Retrospective analysis demonstrated atypical performance in RT and PA at all three time points in children who later developed literacy impairments. Conclusions: Although significant, kindergarten auditory processing contributions to later literacy growth lack the power to be considered as a single-cause predictor; thus results support temporal processing deficits' contribution within a multiple deficit model of dyslexia. PMID:28223953

The influence of levels of processing on recall from working memory and delayed recall tasks.

PubMed

Loaiza, Vanessa M; McCabe, David P; Youngblood, Jessie L; Rose, Nathan S; Myerson, Joel

2011-09-01

Recent research in working memory has highlighted the similarities involved in retrieval from complex span tasks and episodic memory tasks, suggesting that these tasks are influenced by similar memory processes. In the present article, the authors manipulated the level of processing engaged when studying to-be-remembered words during a reading span task (Experiment 1) and an operation span task (Experiment 2) in order to assess the role of retrieval from secondary memory during complex span tasks. Immediate recall from both span tasks was greater for items studied under deep processing instructions compared with items studied under shallow processing instructions regardless of trial length. Recall was better for deep than for shallow levels of processing on delayed recall tests as well. These data are consistent with the primary-secondary memory framework, which suggests that to-be-remembered items are displaced from primary memory (i.e., the focus of attention) during the processing phases of complex span tasks and therefore must be retrieved from secondary memory. (c) 2011 APA, all rights reserved.

Social anhedonia associated with poor evaluative processing but not with poor cognitive control.

PubMed

Martin, Elizabeth A; Kerns, John G

2010-07-30

Emotion researchers have distinguished between automatic vs. controlled processing of evaluative information. There is suggestive evidence that social anhedonia might be associated with problems in controlled evaluative processing. The current study examined whether college students with elevated social anhedonia would exhibit an increased processing effect on tasks involving either evaluative processing or cognitive control. On an evaluative processing task, affective primes and targets could be either congruent or incongruent and participants judged the valence of targets. On a cognitive control task, participants completed the color-naming Stroop task. Compared to control participants (n=47), people with elevated social anhedonia (n=27) exhibited an increased evaluative processing effect as they were slower and made more errors for incongruent than for congruent trials on the evaluative processing task. In contrast, there were no group differences on the Stroop task or on a semantic priming task. Overall, these results suggest that people with elevated social anhedonia might have problems with some aspects of evaluative processing. Copyright 2009 Elsevier Ltd. All rights reserved.

Influence of using challenging tasks in biology classrooms on students' cognitive knowledge structure: an empirical video study

NASA Astrophysics Data System (ADS)

Nawani, Jigna; Rixius, Julia; Neuhaus, Birgit J.

2016-08-01

Empirical analysis of secondary biology classrooms revealed that, on average, 68% of teaching time in Germany revolved around processing tasks. Quality of instruction can thus be assessed by analyzing the quality of tasks used in classroom discourse. This quasi-experimental study analyzed how teachers used tasks in 38 videotaped biology lessons pertaining to the topic 'blood and circulatory system'. Two fundamental characteristics used to analyze tasks include: (1) required cognitive level of processing (e.g. low level information processing: repetiition, summary, define, classify and high level information processing: interpret-analyze data, formulate hypothesis, etc.) and (2) complexity of task content (e.g. if tasks require use of factual, linking or concept level content). Additionally, students' cognitive knowledge structure about the topic 'blood and circulatory system' was measured using student-drawn concept maps (N = 970 students). Finally, linear multilevel models were created with high-level cognitive processing tasks and higher content complexity tasks as class-level predictors and students' prior knowledge, students' interest in biology, and students' interest in biology activities as control covariates. Results showed a positive influence of high-level cognitive processing tasks (β = 0.07; p < .01) on students' cognitive knowledge structure. However, there was no observed effect of higher content complexity tasks on students' cognitive knowledge structure. Presented findings encourage the use of high-level cognitive processing tasks in biology instruction.

Verbal and nonverbal behavior of ability-grouped dyads

NASA Astrophysics Data System (ADS)

Jones, M. Gail; Carter, Glenda

In this study we describe the social interactions of ability-grouped dyads as they constructed knowledge of balance concepts to elucidate the relationship between interactions and conceptual growth. The verbal and nonverbal behaviors of 30 fifth-grade students were recorded as they completed three activities related to balance. These student interactions were examined within a framework of social cognition. For each dyad, characteristics of ability-grouped dyads were identified. Results revealed that high-achieving students effectively used prior experiences, maintained focus on the learning task, and were able to manipulate the equipment effectively to construct knowledge. Low-achieving students exhibited off-task behavior, lacked a metacognitive framework for organizing the learning tasks, centered on irrelevant features of the equipment, and were unable to use language effectively to mediate learning. Within low-high student dyads, high-achieving students typically modeled thinking processes and strategies for manipulating equipment. In addition, they focused the low-achieving students on the components of the tasks while verbally monitoring their progress, thus enabling low students to identify the critical features necessary for concept construction. These results highlighted the differences that students have in the use of language and tools. Low students' inefficient use of tools has implications for the ways science teachers structure lessons and group students for laboratory work.Received: 8 March 1993; Revised: 6 January 1994;

Parallel processing considerations for image recognition tasks

NASA Astrophysics Data System (ADS)

Simske, Steven J.

2011-01-01

Many image recognition tasks are well-suited to parallel processing. The most obvious example is that many imaging tasks require the analysis of multiple images. From this standpoint, then, parallel processing need be no more complicated than assigning individual images to individual processors. However, there are three less trivial categories of parallel processing that will be considered in this paper: parallel processing (1) by task; (2) by image region; and (3) by meta-algorithm. Parallel processing by task allows the assignment of multiple workflows-as diverse as optical character recognition [OCR], document classification and barcode reading-to parallel pipelines. This can substantially decrease time to completion for the document tasks. For this approach, each parallel pipeline is generally performing a different task. Parallel processing by image region allows a larger imaging task to be sub-divided into a set of parallel pipelines, each performing the same task but on a different data set. This type of image analysis is readily addressed by a map-reduce approach. Examples include document skew detection and multiple face detection and tracking. Finally, parallel processing by meta-algorithm allows different algorithms to be deployed on the same image simultaneously. This approach may result in improved accuracy.

A longitudinal study of lexical development in children learning Vietnamese and English.

PubMed

Pham, Giang; Kohnert, Kathryn

2014-01-01

This longitudinal study modeled lexical development among children who spoke Vietnamese as a first language (L1) and English as a second language (L2). Participants (n = 33, initial mean age of 7.3 years) completed a total of eight tasks (four in each language) that measured vocabulary knowledge and lexical processing at four yearly time points. Multivariate hierarchical linear modeling was used to calculate L1 and L2 trajectories within the same model for each task. Main findings included (a) positive growth in each language, (b) greater gains in English resulting in shifts toward L2 dominance, and (c) different patterns for receptive and expressive domains. Timing of shifts to L2 dominance underscored L1 skills that are resilient and vulnerable to increases in L2 proficiency. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

Race-specific perceptual discrimination improvement following short individuation training with faces

PubMed Central

McGugin, Rankin Williams; Tanaka, James W.; Lebrecht, Sophie; Tarr, Michael J.; Gauthier, Isabel

2010-01-01

This study explores the effect of individuation training on the acquisition of race-specific expertise. First, we investigated whether practice individuating other-race faces yields improvement in perceptual discrimination for novel faces of that race. Second, we asked whether there was similar improvement for novel faces of a different race for which participants received equal practice, but in an orthogonal task that did not require individuation. Caucasian participants were trained to individuate faces of one race (African American or Hispanic) and to make difficult eye luminance judgments on faces of the other race. By equating these tasks we are able to rule out raw experience, visual attention or performance/success-induced positivity as the critical factors that produce race-specific improvements. These results indicate that individuation practice is one mechanism through which cognitive, perceptual, and/or social processes promote growth of the own-race face recognition advantage. PMID:21429002

How Entrustment Is Informed by Holistic Judgments Across Time in a Family Medicine Residency Program: An Ethnographic Nonparticipant Observational Study.

PubMed

Sagasser, Margaretha H; Fluit, Cornelia R M G; van Weel, Chris; van der Vleuten, Cees P M; Kramer, Anneke W M

2017-06-01

Entrustment has mainly been conceptualized as delegating discrete professional tasks. Because residents provide most of their patient care independently, not all resident performance is visible to supervisors; the entrustment process involves more than granting discrete tasks. This study explored how supervisors made entrustment decisions based on residents' performance in a long-term family medicine training program. A qualitative nonparticipant observational study was conducted in 2014-2015 at competency-based family medicine residency programs in the Netherlands. Seven supervisor-resident pairs participated. During two days, one researcher observed first-year residents' patient encounters, debriefing sessions, and supervisor-resident educational meetings and interviewed them separately afterwards. Data were collected and analyzed using iterative, phenomenological inductive research methodology. The entrustment process developed over three phases. Supervisors based their initial entrustment on prior knowledge about the resident. In the ensuing two weeks, entrustment decisions regarding independent patient care were derived from residents' observed general competencies necessary for a range of health problems (clinical reasoning, decision making, relating to patients); medical knowledge and skills; and supervisors' intuition. Supervisors provided supervision during and after encounters. Once residents performed independently, supervisors kept reevaluating their decisions, informed by residents' overall growth in competencies rather than by adhering to a predefined set of tasks. Supervisors in family medicine residency training took a holistic approach to trust, based on general competencies, knowledge, skills, and intuition. Entrustment started before training and developed over time. Building trust is a mutual process between supervisor and resident, requiring a good working relationship.

The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference

PubMed Central

Gabriel, Florence C.; Szücs, Dénes

2014-01-01

Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference. PMID:25249995

The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference.

PubMed

Zhang, Li; Fang, Qiaochu; Gabriel, Florence C; Szücs, Dénes

2014-01-01

Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference.

Spatial information is processed even when it is task-irrelevant: implications for neuroimaging task design.

PubMed

Meegan, Daniel V; Honsberger, Michael J M

2005-05-01

Many neuroimaging studies have been designed to differentiate domain-specific processes in the brain. A common design constraint is to use identical stimuli for different domain-specific tasks. For example, an experiment investigating spatial versus identity processing would present compound spatial-identity stimuli in both spatial and identity tasks, and participants would be instructed to attend to, encode, maintain, or retrieve spatial information in the spatial task, and identity information in the identity task. An assumption in such studies is that spatial information will not be processed in the identity task, as it is irrelevant for that task. We report three experiments demonstrating violations of this assumption. Our results suggest that comparisons of spatial and identity tasks in existing neuroimaging studies have underestimated the amount of brain activation that is spatial-specific. For future neuroimaging studies, we recommend unique stimulus displays for each domain-specific task, and event-related measurement of post-stimulus processing.

Identification of Occupational Areas for Indiana's Future. Final Report of the Technology Forecasting Task Force.

ERIC Educational Resources Information Center

Indiana State Commission on Vocational and Technical Education, Indianapolis.

A task force representing the Indiana private sector was convened for two purposes: to (1) identify the impact of technology on required worker skills, the labor market, and the vocational education, training, and employment system; and (2) identify occupational areas that should be future growth areas for the state. Task force members reviewed…

Dual-Task Processing in Younger and Older Adults: Similarities and Differences Revealed by fMRI

ERIC Educational Resources Information Center

Hartley, Alan A.; Jonides, John; Sylvester, Ching-Yune C.

2011-01-01

fMRI was used to explore age differences in the neural substrate of dual-task processing. Brain activations when there was a 100 ms SOA between tasks, and task overlap was high, were contrasted with activations when there was a 1000 ms SOA, and first task processing was largely complete before the second task began. Younger adults (M = 21 yrs)…

Bridging Grafts and Transient Nerve Growth Factor Infusions Promote Long-Term Central Nervous System Neuronal Rescue and Partial Functional Recovery

NASA Astrophysics Data System (ADS)

Tuszynski, Mark H.; Gage, Fred H.

1995-05-01

Grafts of favorable axonal growth substrates were combined with transient nerve growth factor (NGF) infusions to promote morphological and functional recovery in the adult rat brain after lesions of the septohippocampal projection. Long-term septal cholinergic neuronal rescue and partial hippocampal reinnervation were achieved, resulting in partial functional recovery on a simple task assessing habituation but not on a more complex task assessing spatial reference memory. Control animals that received transient NGF infusions without axonal-growth-promoting grafts lacked behavioral recovery but also showed long-term septal neuronal rescue. These findings indicate that (i) partial recovery from central nervous system injury can be induced by both preventing host neuronal loss and promoting host axonal regrowth and (ii) long-term neuronal loss can be prevented with transient NGF infusions.

Distinct and Overlapping Brain Areas Engaged during Value-Based, Mathematical, and Emotional Decision Processing

PubMed Central

Hsu, Chun-Wei; Goh, Joshua O. S.

2016-01-01

When comparing between the values of different choices, human beings can rely on either more cognitive processes, such as using mathematical computation, or more affective processes, such as using emotion. However, the neural correlates of how these two types of processes operate during value-based decision-making remain unclear. In this study, we investigated the extent to which neural regions engaged during value-based decision-making overlap with those engaged during mathematical and emotional processing in a within-subject manner. In a functional magnetic resonance imaging experiment, participants viewed stimuli that always consisted of numbers and emotional faces that depicted two choices. Across tasks, participants decided between the two choices based on the expected value of the numbers, a mathematical result of the numbers, or the emotional face stimuli. We found that all three tasks commonly involved various cortical areas including frontal, parietal, motor, somatosensory, and visual regions. Critically, the mathematical task shared common areas with the value but not emotion task in bilateral striatum. Although the emotion task overlapped with the value task in parietal, motor, and sensory areas, the mathematical task also evoked responses in other areas within these same cortical structures. Minimal areas were uniquely engaged for the value task apart from the other two tasks. The emotion task elicited a more expansive area of neural activity whereas value and mathematical task responses were in more focal regions. Whole-brain spatial correlation analysis showed that valuative processing engaged functional brain responses more similarly to mathematical processing than emotional processing. While decisions on expected value entail both mathematical and emotional processing regions, mathematical processes have a more prominent contribution particularly in subcortical processes. PMID:27375466

Distinct and Overlapping Brain Areas Engaged during Value-Based, Mathematical, and Emotional Decision Processing.

PubMed

Hsu, Chun-Wei; Goh, Joshua O S

2016-01-01

When comparing between the values of different choices, human beings can rely on either more cognitive processes, such as using mathematical computation, or more affective processes, such as using emotion. However, the neural correlates of how these two types of processes operate during value-based decision-making remain unclear. In this study, we investigated the extent to which neural regions engaged during value-based decision-making overlap with those engaged during mathematical and emotional processing in a within-subject manner. In a functional magnetic resonance imaging experiment, participants viewed stimuli that always consisted of numbers and emotional faces that depicted two choices. Across tasks, participants decided between the two choices based on the expected value of the numbers, a mathematical result of the numbers, or the emotional face stimuli. We found that all three tasks commonly involved various cortical areas including frontal, parietal, motor, somatosensory, and visual regions. Critically, the mathematical task shared common areas with the value but not emotion task in bilateral striatum. Although the emotion task overlapped with the value task in parietal, motor, and sensory areas, the mathematical task also evoked responses in other areas within these same cortical structures. Minimal areas were uniquely engaged for the value task apart from the other two tasks. The emotion task elicited a more expansive area of neural activity whereas value and mathematical task responses were in more focal regions. Whole-brain spatial correlation analysis showed that valuative processing engaged functional brain responses more similarly to mathematical processing than emotional processing. While decisions on expected value entail both mathematical and emotional processing regions, mathematical processes have a more prominent contribution particularly in subcortical processes.

The impact of the stimulus features and task instructions on facial processing in social anxiety: an ERP investigation.

PubMed

Peschard, Virginie; Philippot, Pierre; Joassin, Frédéric; Rossignol, Mandy

2013-04-01

Social anxiety has been characterized by an attentional bias towards threatening faces. Electrophysiological studies have demonstrated modulations of cognitive processing from 100 ms after stimulus presentation. However, the impact of the stimulus features and task instructions on facial processing remains unclear. Event-related potentials were recorded while high and low socially anxious individuals performed an adapted Stroop paradigm that included a colour-naming task with non-emotional stimuli, an emotion-naming task (the explicit task) and a colour-naming task (the implicit task) on happy, angry and neutral faces. Whereas the impact of task factors was examined by contrasting an explicit and an implicit emotional task, the effects of perceptual changes on facial processing were explored by including upright and inverted faces. The findings showed an enhanced P1 in social anxiety during the three tasks, without a moderating effect of the type of task or stimulus. These results suggest a global modulation of attentional processing in performance situations. Copyright © 2013 Elsevier B.V. All rights reserved.

A dual-task investigation of automaticity in visual word processing

NASA Technical Reports Server (NTRS)

McCann, R. S.; Remington, R. W.; Van Selst, M.

2000-01-01

An analysis of activation models of visual word processing suggests that frequency-sensitive forms of lexical processing should proceed normally while unattended. This hypothesis was tested by having participants perform a speeded pitch discrimination task followed by lexical decisions or word naming. As the stimulus onset asynchrony between the tasks was reduced, lexical-decision and naming latencies increased dramatically. Word-frequency effects were additive with the increase, indicating that frequency-sensitive processing was subject to postponement while attention was devoted to the other task. Either (a) the same neural hardware shares responsibility for lexical processing and central stages of choice reaction time task processing and cannot perform both computations simultaneously, or (b) lexical processing is blocked in order to optimize performance on the pitch discrimination task. Either way, word processing is not as automatic as activation models suggest.

Integrated aerodynamic-structural design of a forward-swept transport wing

NASA Technical Reports Server (NTRS)

Haftka, Raphael T.; Grossman, Bernard; Kao, Pi-Jen; Polen, David M.; Sobieszczanski-Sobieski, Jaroslaw

1989-01-01

The introduction of composite materials is having a profound effect on aircraft design. Since these materials permit the designer to tailor material properties to improve structural, aerodynamic and acoustic performance, they require an integrated multidisciplinary design process. Futhermore, because of the complexity of the design process, numerical optimization methods are required. The utilization of integrated multidisciplinary design procedures for improving aircraft design is not currently feasible because of software coordination problems and the enormous computational burden. Even with the expected rapid growth of supercomputers and parallel architectures, these tasks will not be practical without the development of efficient methods for cross-disciplinary sensitivities and efficient optimization procedures. The present research is part of an on-going effort which is focused on the processes of simultaneous aerodynamic and structural wing design as a prototype for design integration. A sequence of integrated wing design procedures has been developed in order to investigate various aspects of the design process.

A comparison of conscious and automatic memory processes for picture and word stimuli: a process dissociation analysis.

PubMed

McBride, Dawn M; Anne Dosher, Barbara

2002-09-01

Four experiments were conducted to evaluate explanations of picture superiority effects previously found for several tasks. In a process dissociation procedure (Jacoby, 1991) with word stem completion, picture fragment completion, and category production tasks, conscious and automatic memory processes were compared for studied pictures and words with an independent retrieval model and a generate-source model. The predictions of a transfer appropriate processing account of picture superiority were tested and validated in "process pure" latent measures of conscious and unconscious, or automatic and source, memory processes. Results from both model fits verified that pictures had a conceptual (conscious/source) processing advantage over words for all tasks. The effects of perceptual (automatic/word generation) compatibility depended on task type, with pictorial tasks favoring pictures and linguistic tasks favoring words. Results show support for an explanation of the picture superiority effect that involves an interaction of encoding and retrieval processes.

Running Memory for Clinical Handoffs: A Look at Active and Passive Processing.

PubMed

Anderson-Montoya, Brittany L; Scerbo, Mark W; Ramirez, Dana E; Hubbard, Thomas W

2017-05-01

The goal of the present study was to examine the effects of domain-relevant expertise on running memory and the ability to process handoffs of information. In addition, the role of active or passive processing was examined. Currently, there is little research that addresses how individuals with different levels of expertise process information in running memory when the information is needed to perform a real-world task. Three groups of participants differing in their level of clinical expertise (novice, intermediate, and expert) performed an abstract running memory span task and two tasks resembling real-world activities, a clinical handoff task and an air traffic control (ATC) handoff task. For all tasks, list length and the amount of information to be recalled were manipulated. Regarding processing strategy, all participants used passive processing for the running memory span and ATC tasks. The novices also used passive processing for the clinical task. The experts, however, appeared to use more active processing, and the intermediates fell in between. Overall, the results indicated that individuals with clinical expertise and a developed mental model rely more on active processing of incoming information for the clinical task while individuals with little or no knowledge rely on passive processing. The results have implications about how training should be developed to aid less experienced personnel identify what information should be included in a handoff and what should not.

Advanced thermally stable jet fuels: Technical progress report, October 1994--December 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schobert, H.H.; Eser, S.; Song, C.

There are five tasks within this project on thermally stable coal-based jet fuels. Progress on each of the tasks is described. Task 1, Investigation of the quantitative degradation chemistry of fuels, has 5 subtasks which are described: Literature review on thermal stability of jet fuels; Pyrolytic and catalytic reactions of potential endothermic fuels: cis- and trans-decalin; Use of site specific {sup 13}C-labeling to examine the thermal stressing of 1-phenylhexane: A case study for the determination of reaction kinetics in complex fuel mixtures versus model compound studies; Estimation of critical temperatures of jet fuels; and Surface effects on deposit formation inmore » a flow reactor system. Under Task 2, Investigation of incipient deposition, the subtask reported is Uncertainty analysis on growth and deposition of particles during heating of coal-derived aviation gas turbine fuels; under Task 3, Characterization of solid gums, sediments, and carbonaceous deposits, is subtask, Studies of surface chemistry of PX-21 activated carbon during thermal degradation of jet A-1 fuel and n-dodecane; under Task 4, Coal-based fuel stabilization studies, is subtask, Exploratory screening and development potential of jet fuel thermal stabilizers over 400 C; and under Task 5, Exploratory studies on the direct conversion of coal to high quality jet fuels, are 4 subtasks: Novel approaches to low-severity coal liquefaction and coal/resid co-processing using water and dispersed catalysts; Shape-selective naphthalene hydrogenation for production of thermally stable jet fuels; Design of a batch mode and a continuous mode three-phase reactor system for the liquefaction of coal and upgrading of coal liquids; and Exploratory studies on coal liquids upgrading using mesopores molecular sieve catalysts. 136 refs., 69 figs., 24 tabs.« less

A new system for sodium flux growth of bulk GaN. Part I: System development

NASA Astrophysics Data System (ADS)

Von Dollen, Paul; Pimputkar, Siddha; Alreesh, Mohammed Abo; Albrithen, Hamad; Suihkonen, Sami; Nakamura, Shuji; Speck, James S.

2016-12-01

Though several methods exist to produce bulk crystals of gallium nitride (GaN), none have been commercialized on a large scale. The sodium flux method, which involves precipitation of GaN from a sodium-gallium melt supersaturated with nitrogen, offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. We successfully developed a novel apparatus for conducting crystal growth of bulk GaN using the sodium flux method which has advantages with respect to prior reports. A key task was to prevent sodium loss or migration from the growth environment while permitting N2 to access the growing crystal. We accomplished this by implementing a reflux condensing stem along with a reusable capsule containing a hermetic seal. The reflux condensing stem also enabled direct monitoring of the melt temperature, which has not been previously reported for the sodium flux method. Furthermore, we identified and utilized molybdenum and the molybdenum alloy TZM as a material capable of directly containing the corrosive sodium-gallium melt. This allowed implementation of a crucible-free system, which may improve process control and potentially lower crystal impurity levels. Nucleation and growth of parasitic GaN ("PolyGaN") on non-seed surfaces occurred in early designs. However, the addition of carbon in later designs suppressed PolyGaN formation and allowed growth of single crystal GaN. Growth rates for the (0001) Ga face (+c-plane) were up to 14 μm/h while X-ray omega rocking (ω-XRC) curve full width half-max values were 731″ for crystals grown using a later system design. Oxygen levels were high, >1019 atoms/cm3, possibly due to reactor cleaning and handling procedures.

Neural Correlates of Math Gains Vary Depending on Parental Socioeconomic Status (SES)

PubMed Central

Demir-Lira, Özlem Ece; Prado, Jérôme; Booth, James R.

2016-01-01

We used functional magnetic resonance imaging (fMRI) to examine the neural predictors of math development, and asked whether these predictors vary as a function of parental socioeconomic status (SES) in children ranging in age from 8 to 13 years. We independently localized brain regions subserving verbal versus spatial processing in order to characterize relations between activation in these regions during an arithmetic task and long-term change in math skill (up to 3 years). Neural predictors of math gains encompassed brain regions subserving both verbal and spatial processing, but the relation between relative reliance on these regions and math skill growth varied depending on parental SES. Activity in an area of the left inferior frontal gyrus (IFG) identified by the verbal localizer was related to greater growth in math skill at the higher end of the SES continuum, but lesser improvements at the lower end. Activity in an area of the right superior parietal cortex identified by the spatial localizer was related to greater growth in math skill at the lower end of the SES continuum, but lesser improvements at the higher end. Results highlight early neural mechanisms as possible neuromarkers of long-term arithmetic learning and suggest that neural predictors of math gains vary with parental SES. PMID:27378987

Large-area silicon sheet task

NASA Technical Reports Server (NTRS)

Morrison, A. D.

1982-01-01

A set of computer models was used to define a growth system configuration that was then built and used to grow web with lower thermally generated stress. Aspects of research in the edge-defined film-fed growth (EFG) method of making Si ribbon are reported. A technique was developed to determine base resistivity and carrier lifetime in semicrystalline wafers. Automated growth of 150 kg of 15 cm-dia ingot material per crucible is reviewed. Scanning transmisson electron microscopy (STEM) and microprobe investigations of processed EFG ribbon are reported. The chemical composition of the large precipitates was studied. The structural arrangement and the electrical activity of distentions or close to the central twin plane in processed material were studied. The electrical and structural properties of grain boundaries in silicon are discussed. Temperature-dependence measurements of zero-bias conductance, a photoconductivity technique, and deep-level transient spectroscopy (DLTS) were developed. A grooving and staining technique, secondary ion mass spectroscopy, and EBIC measurements in scanning electron microscopy were used to study enhanced diffusion of phosphorus at grain boundaries in polycrystaline silicon. The fundamental mechanisms of abrasion and wear and the deformation of Si by a diamond in various fluid environments are described. The efficiency of solar cells made from EFG ribbon and Semix Inc. material is reported.

Slicing of Silicon into Sheet Material. Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Solar Array Project

NASA Technical Reports Server (NTRS)

Fleming, J. R.; Holden, S. C.; Wolfson, R. G.

1979-01-01

The use of multiblade slurry sawing to produce silicon wafers from ingots was investigated. The commercially available state of the art process was improved by 20% in terms of area of silicon wafers produced from an ingot. The process was improved 34% on an experimental basis. Economic analyses presented show that further improvements are necessary to approach the desired wafer costs, mostly reduction in expendable materials costs. Tests which indicate that such reduction is possible are included, although demonstration of such reduction was not completed. A new, large capacity saw was designed and tested. Performance comparable with current equipment (in terms of number of wafers/cm) was demonstrated.

Beyond the initial 140 ms, lexical decision and reading aloud are different tasks: An ERP study with topographic analysis.

PubMed

Mahé, Gwendoline; Zesiger, Pascal; Laganaro, Marina

2015-11-15

Most of our knowledge on the time-course of the mechanisms involved in reading derived from electrophysiological studies is based on lexical decision tasks. By contrast, very few ERP studies investigated the processes involved in reading aloud. It has been suggested that the lexical decision task provides a good index of the processes occurring during reading aloud, with only late processing differences related to task response modalities. However, some behavioral studies reported different sensitivity to psycholinguistic factors between the two tasks, suggesting that print processing could differ at earlier processing stages. The aim of the present study was thus to carry out an ERP comparison between lexical decision and reading aloud in order to determine when print processing differs between these two tasks. Twenty native French speakers performed a lexical decision task and a reading aloud task with the same written stimuli. Results revealed different electrophysiological patterns on both waveform amplitudes and global topography between lexical decision and reading aloud from about 140 ms after stimulus presentation for both words and pseudowords, i.e., as early as the N170 component. These results suggest that only very early, low-level visual processes are common to the two tasks which differ in core processes. Taken together, our main finding questions the use of the lexical decision task as an appropriate paradigm to investigate reading processes and warns against generalizing its results to word reading. Copyright © 2015 Elsevier Inc. All rights reserved.

Serial or overlapping processing in multitasking as individual preference: Effects of stimulus preview on task switching and concurrent dual-task performance.

PubMed

Reissland, Jessika; Manzey, Dietrich

2016-07-01

Understanding the mechanisms and performance consequences of multitasking has long been in focus of scientific interest, but has been investigated by three research lines more or less isolated from each other. Studies in the fields of the psychological refractory period, task switching, and interruptions have scored with a high experimental control, but usually do not give participants many degrees of freedom to self-organize the processing of two concurrent tasks. Individual strategies as well as their impact on efficiency have mainly been neglected. Self-organized multitasking has been investigated in the field of human factors, but primarily with respect to overall performance without detailed investigation of how the tasks are processed. The current work attempts to link aspects of these research lines. All of them, explicitly or implicitly, provide hints about an individually preferred type of task organization, either more cautious trying to work strictly serially on only one task at a time or more daring with a focus on task interleaving and, if possible, also partially overlapping (parallel) processing. In two experiments we investigated different strategies of task organization and their impact on efficiency using a new measure of overall multitasking efficiency. Experiment 1 was based on a classical task switching paradigm with two classification tasks, but provided one group of participants with a stimulus preview of the task to switch to next, enabling at least partial overlapping processing. Indeed, this preview led to a reduction of switch costs and to an increase of dual-task efficiency, but only for a subgroup of participants. They obviously exploited the possibility of overlapping processing, while the others worked mainly serially. While task-sequence was externally guided in the first experiment, Experiment 2 extended the approach by giving the participants full freedom of task organization in concurrent performance of the same tasks. Fine-grained analyses of response scheduling again revealed individual differences regarding the preference for strictly serial processing vs. some sort of task interleaving and overlapping processing. However, neither group showed a striking benefit in dual-task efficiency, although the results show that the costs of multitasking can partly be compensated by overlapping processing. Copyright © 2016 Elsevier B.V. All rights reserved.

Temporal dynamics of interference in Simon and Eriksen tasks considered within the context of a dual-process model.

PubMed

Mansfield, Karen L; van der Molen, Maurits W; Falkenstein, Michael; van Boxtel, Geert J M

2013-08-01

Behavioral and brain potential measures were employed to compare interference in Eriksen and Simon tasks. Assuming a dual-process model of interference elicited in speeded response tasks, we hypothesized that only lateralized stimuli in the Simon task induce fast S-R priming via direct unconditional processes, while Eriksen interference effects are induced later via indirect conditional processes. Delays to responses for incongruent trials were indeed larger in the Eriksen than in the Simon task. Only lateralized stimuli in the Simon task elicited early S-R priming, maximal at parietal areas. Incongruent flankers in the Eriksen task elicited interference later, visible as a lateralized N2. Eriksen interference also elicited an additional component (N350), which accounted for the larger behavioral interference effects in the Eriksen task. The findings suggest that interference and its resolution involve different processes for Simon and Eriksen tasks. Copyright © 2013 Elsevier Inc. All rights reserved.

Silicon materials task of the low cost solar array project, phase 2

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Davis, J. R., Jr.; Blais, P. D.; Rohatgi, A.; Rai-Choudhury, P.; Hanes, M. H.; Mccormick, J. R.

1977-01-01

The object of phase 2 of this program is to investigate and define the effects of various processes, contaminants and process-contaminant interactions in the performance of terrestrial solar cells. The major effort this quarter was in the areas of crystal growth and thermal processing, comparison of impurity effects in low and high resistivity silicon, modeling the behavior of p-type ingots containing Mo, and C and, quantitative analysis of bulk lifetime and junction degradation effects in contaminated solar cells. The performance of solar cells fabricated on silicon web crystals grown from melts containing about 10 to the 18th power/cu cm of Cr, Mn, Fe, Ni, Ti, and V, respectively were measured. Deep level spectroscopy of metal-contaminated ingots was employed to determine the level and density of recombination centers due to Ti, V, Ni, and Cr.

Tackling creativity at its roots: Evidence for different patterns of EEG alpha activity related to convergent and divergent modes of task processing

PubMed Central

Jauk, Emanuel; Benedek, Mathias; Neubauer, Aljoscha C.

2012-01-01

The distinction between convergent and divergent cognitive processes given by Guilford (1956) had a strong influence on the empirical research on creative thinking. Neuroscientific studies typically find higher event-related synchronization in the EEG alpha rhythm for individuals engaged in creative ideation tasks compared to intelligence-related tasks. This study examined, whether these neurophysiological effects can also be found when both cognitive processing modes (convergent vs. divergent) are assessed by means of the same task employing a simple variation of instruction. A sample of 55 participants performed the alternate uses task as well as a more basic word association task while EEG was recorded. On a trial-by-trial basis, participants were either instructed to find a most common solution (convergent condition) or a most uncommon solution (divergent condition). The answers given in the divergent condition were in both tasks significantly more original than those in the convergent condition. Moreover, divergent processing was found to involve higher task-related EEG alpha power than convergent processing in both the alternate uses task and the word association task. EEG alpha synchronization can hence explicitly be associated with divergent cognitive processing rather than with general task characteristics of creative ideation tasks. Further results point to a differential involvement of frontal and parietal cortical areas by individuals of lower versus higher trait creativity. PMID:22390860

Pre-processing Tasks in Indonesian Twitter Messages

NASA Astrophysics Data System (ADS)

Hidayatullah, A. F.; Ma'arif, M. R.

2017-01-01

Twitter text messages are very noisy. Moreover, tweet data are unstructured and complicated enough. The focus of this work is to investigate pre-processing technique for Twitter messages in Bahasa Indonesia. The main goal of this experiment is to clean the tweet data for further analysis. Thus, the objectives of this pre-processing task is simply removing all meaningless character and left valuable words. In this research, we divide our proposed pre-processing experiments into two parts. The first part is common pre-processing task. The second part is a specific pre-processing task for tweet data. From the experimental result we can conclude that by employing a specific pre-processing task related to tweet data characteristic we obtained more valuable result. The result obtained is better in terms of less meaningful word occurrence which is not significant in number comparing to the result obtained by just running common pre-processing tasks.

A Verification Method of Inter-Task Cooperation in Embedded Real-time Systems and its Evaluation

NASA Astrophysics Data System (ADS)

Yoshida, Toshio

In software development process of embedded real-time systems, the design of the task cooperation process is very important. The cooperating process of such tasks is specified by task cooperation patterns. Adoption of unsuitable task cooperation patterns has fatal influence on system performance, quality, and extendibility. In order to prevent repetitive work caused by the shortage of task cooperation performance, it is necessary to verify task cooperation patterns in an early software development stage. However, it is very difficult to verify task cooperation patterns in an early software developing stage where task program codes are not completed yet. Therefore, we propose a verification method using task skeleton program codes and a real-time kernel that has a function of recording all events during software execution such as system calls issued by task program codes, external interrupts, and timer interrupt. In order to evaluate the proposed verification method, we applied it to the software development process of a mechatronics control system.

Microgravity Science and Applications Program tasks, 1986 revision

NASA Technical Reports Server (NTRS)

1987-01-01

The Microgravity Science and Applications (MSA) program is directed toward research in the science and technology of processing materials under conditions of low gravity to provide a detailed examination of the constraints imposed by gravitational forces on Earth. The program is expected to lead to the development of new materials and processes in commercial applications adding to this nation's technological base. The research studies emphasize the selected materials and processes that will best elucidate the limitations due to gravity and demonstrate the enhanced sensitivity of control of processes that may be provided by the weightless environment of space. Primary effort is devoted to a study of the specific areas of research which reveals potential value in the initial investigations of the previous decades. Examples of previous process research include crystal growth and directional solidification of metals; containerless processing of reactive materials; synthesis and separation of biological materials; etc. Additional efforts will be devoted to identifying the special requirements which drive the design of hardware to reduce risk in future developments.

Information Processing in Memory Tasks.

ERIC Educational Resources Information Center

Johnston, William A.

The intensity of information processing engendered in different phases of standard memory tasks was examined in six experiments. Processing intensity was conceptualized as system capacity consumed, and was measured via a divided-attention procedure in which subjects performed a memory task and a simple reaction-time (RT) task concurrently. The…

Application of a COTS Resource Optimization Framework to the SSN Sensor Tasking Domain - Part I: Problem Definition

NASA Astrophysics Data System (ADS)

Tran, T.

With the onset of the SmallSat era, the RSO catalog is expected to see continuing growth in the near future. This presents a significant challenge to the current sensor tasking of the SSN. The Air Force is in need of a sensor tasking system that is robust, efficient, scalable, and able to respond in real-time to interruptive events that can change the tracking requirements of the RSOs. Furthermore, the system must be capable of using processed data from heterogeneous sensors to improve tasking efficiency. The SSN sensor tasking can be regarded as an economic problem of supply and demand: the amount of tracking data needed by each RSO represents the demand side while the SSN sensor tasking represents the supply side. As the number of RSOs to be tracked grows, demand exceeds supply. The decision-maker is faced with the problem of how to allocate resources in the most efficient manner. Braxton recently developed a framework called Multi-Objective Resource Optimization using Genetic Algorithm (MOROUGA) as one of its modern COTS software products. This optimization framework took advantage of the maturing technology of evolutionary computation in the last 15 years. This framework was applied successfully to address the resource allocation of an AFSCN-like problem. In any resource allocation problem, there are five key elements: (1) the resource pool, (2) the tasks using the resources, (3) a set of constraints on the tasks and the resources, (4) the objective functions to be optimized, and (5) the demand levied on the resources. In this paper we explain in detail how the design features of this optimization framework are directly applicable to address the SSN sensor tasking domain. We also discuss our validation effort as well as present the result of the AFSCN resource allocation domain using a prototype based on this optimization framework.

Barriers to success: physical separation optimizes event-file retrieval in shared workspaces.

PubMed

Klempova, Bibiana; Liepelt, Roman

2017-07-08

Sharing tasks with other persons can simplify our work and life, but seeing and hearing other people's actions may also be very distracting. The joint Simon effect (JSE) is a standard measure of referential response coding when two persons share a Simon task. Sequential modulations of the joint Simon effect (smJSE) are interpreted as a measure of event-file processing containing stimulus information, response information and information about the just relevant control-state active in a given social situation. This study tested effects of physical (Experiment 1) and virtual (Experiment 2) separation of shared workspaces on referential coding and event-file processing using a joint Simon task. In Experiment 1, participants performed this task in individual (go-nogo), joint and standard Simon task conditions with and without a transparent curtain (physical separation) placed along the imagined vertical midline of the monitor. In Experiment 2, participants performed the same tasks with and without receiving background music (virtual separation). For response times, physical separation enhanced event-file retrieval indicated by an enlarged smJSE in the joint Simon task with curtain than without curtain (Experiment1), but did not change referential response coding. In line with this, we also found evidence for enhanced event-file processing through physical separation in the joint Simon task for error rates. Virtual separation did neither impact event-file processing, nor referential coding, but generally slowed down response times in the joint Simon task. For errors, virtual separation hampered event-file processing in the joint Simon task. For the cognitively more demanding standard two-choice Simon task, we found music to have a degrading effect on event-file retrieval for response times. Our findings suggest that adding a physical separation optimizes event-file processing in shared workspaces, while music seems to lead to a more relaxed task processing mode under shared task conditions. In addition, music had an interfering impact on joint error processing and more generally when dealing with a more complex task in isolation.

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

PubMed Central

Salo, Emma; Rinne, Teemu; Salonen, Oili; Alho, Kimmo

2015-01-01

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. PMID:25767443

Incorporating domain knowledge in chemical and biomedical named entity recognition with word representations.

PubMed

Munkhdalai, Tsendsuren; Li, Meijing; Batsuren, Khuyagbaatar; Park, Hyeon Ah; Choi, Nak Hyeon; Ryu, Keun Ho

2015-01-01

Chemical and biomedical Named Entity Recognition (NER) is an essential prerequisite task before effective text mining can begin for biochemical-text data. Exploiting unlabeled text data to leverage system performance has been an active and challenging research topic in text mining due to the recent growth in the amount of biomedical literature. We present a semi-supervised learning method that efficiently exploits unlabeled data in order to incorporate domain knowledge into a named entity recognition model and to leverage system performance. The proposed method includes Natural Language Processing (NLP) tasks for text preprocessing, learning word representation features from a large amount of text data for feature extraction, and conditional random fields for token classification. Other than the free text in the domain, the proposed method does not rely on any lexicon nor any dictionary in order to keep the system applicable to other NER tasks in bio-text data. We extended BANNER, a biomedical NER system, with the proposed method. This yields an integrated system that can be applied to chemical and drug NER or biomedical NER. We call our branch of the BANNER system BANNER-CHEMDNER, which is scalable over millions of documents, processing about 530 documents per minute, is configurable via XML, and can be plugged into other systems by using the BANNER Unstructured Information Management Architecture (UIMA) interface. BANNER-CHEMDNER achieved an 85.68% and an 86.47% F-measure on the testing sets of CHEMDNER Chemical Entity Mention (CEM) and Chemical Document Indexing (CDI) subtasks, respectively, and achieved an 87.04% F-measure on the official testing set of the BioCreative II gene mention task, showing remarkable performance in both chemical and biomedical NER. BANNER-CHEMDNER system is available at: https://bitbucket.org/tsendeemts/banner-chemdner.

Predicting Reading Growth with Event-Related Potentials: Thinking Differently about Indexing “Responsiveness”

PubMed Central

Lemons, Christopher J.; Key, Alexandra P.F.; Fuchs, Douglas; Yoder, Paul J.; Fuchs, Lynn S.; Compton, Donald L.; Williams, Susan M.; Bouton, Bobette

2009-01-01

The purpose of this study was to determine if event-related potential (ERP) data collected during three reading-related tasks (Letter Sound Matching, Nonword Rhyming, and Nonword Reading) could be used to predict short-term reading growth on a curriculum-based measure of word identification fluency over 19 weeks in a sample of 29 first-grade children. Results indicate that ERP responses to the Letter Sound Matching task were predictive of reading change and remained so after controlling for two previously validated behavioral predictors of reading, Rapid Letter Naming and Segmenting. ERP data for the other tasks were not correlated with reading change. The potential for cognitive neuroscience to enhance current methods of indexing responsiveness in a response-to-intervention (RTI) model is discussed. PMID:20514353

Child–Adult Differences in Using Dual-Task Paradigms to Measure Listening Effort

PubMed Central

Charles, Lauren M.; Ricketts, Todd A.

2017-01-01

Purpose The purpose of the project was to investigate the effects modifying the secondary task in a dual-task paradigm to measure objective listening effort. To be specific, the complexity and depth of processing were increased relative to a simple secondary task. Method Three dual-task paradigms were developed for school-age children. The primary task was word recognition. The secondary task was a physical response to a visual probe (simple task), a physical response to a complex probe (increased complexity), or word categorization (increased depth of processing). Sixteen adults (22–32 years, M = 25.4) and 22 children (9–17 years, M = 13.2) were tested using the 3 paradigms in quiet and noise. Results For both groups, manipulations of the secondary task did not affect word recognition performance. For adults, increasing depth of processing increased the calculated effect of noise; however, for children, results with the deep secondary task were the least stable. Conclusions Manipulations of the secondary task differentially affected adults and children. Consistent with previous findings, increased depth of processing enhanced paradigm sensitivity for adults. However, younger participants were more likely to demonstrate the expected effects of noise on listening effort using a secondary task that did not require deep processing. PMID:28346816

[Population changes and social welfare tasks].

PubMed

Lee, H K

1985-07-01

Efforts to control population growth made during the last 20 years are expected to maintain a stable population in the future. We cannot limit our concern to the control of population growth but must consider the social welfare task in the aspect of population stability. It is not because population changes set limits to artificial control, but because the order of population changes presents a desirable sign for low fertility. Another important concern is to pay attention to how to make human beings already born and those to be born in the future enjoy their quality of life. Socioeconomic stability requires economic stabilization to meet basic essential needs. Changes in population structure, along with the quantitative growth of population, make changes in patterns of social welfare demands. When the pyramid type of population structure becomes changed to the bell or pot type of population structure, changes in education and employment as well as changes in problems of the aged and medical demands must be made. On the other hand, population changes accompany value changes in the process of modernization of society. These multiple social changes bring about a value of individualism and a nuclear family norm, and an enlargement of women's social participation which, in turn, can cause family problems. At the same time, social deviations and failures may be increased in the industrial society, and, thus, welfare countermeasures have to be taken. In this respect, the base of social welfare for meeting basic demands must be formed not in the past, narrow sense but in the long range and multisided aspects.

Matematical modeling of galophytic plants productivity taking into account the temperature factor and soil salinity level

NASA Astrophysics Data System (ADS)

Natalia, Slyusar; Pisman, Tamara; Pechurkin, Nikolai S.

Among the most challenging tasks faced by contemporary ecology is modeling of biological production process in different plant communities. The difficulty of the task is determined by the complexity of the study material. Models showing the influence of climate and climate change on plant growth, which would also involve soil site parameters, could be of both practical and theoretical interest. In this work a mathematical model has been constructed to describe the growth dynamics of different plant communities of halophytic meadows as dependent upon the temperature factor and soil salinity level, which could be further used to predict yields of these plant communities. The study was performed on plants of halophytic meadows in the coastal area of Lake of the Republic of Khakasia in 2004 - 2006. Every plant community grew on the soil of a different level of salinity - the amount of the solid residue of the saline soil aqueous extract. The mathematical model was analyzed using field data of 2004 and 2006, the years of contrasting air temperatures. Results of model investigations show that there is a correlation between plant growth and the temperature of the air for plant communities growing on soils containing the lowest (0.1Thus, results of our study, in which we used a mathematical model describing the development of plant communities of halophytic meadows and field measurements, suggest that both climate conditions (temperature) and ecological factors of the plants' habitat (soil salinity level) should be taken into account when constructing models for predicting crop yields.

No psychological effect of color context in a low level vision task

PubMed Central

Pedley, Adam; Wade, Alex R

2013-01-01

Background: A remarkable series of recent papers have shown that colour can influence performance in cognitive tasks. In particular, they suggest that viewing a participant number printed in red ink or other red ancillary stimulus elements improves performance in tasks requiring local processing and impedes performance in tasks requiring global processing whilst the reverse is true for the colour blue. The tasks in these experiments require high level cognitive processing such as analogy solving or remote association tests and the chromatic effect on local vs. global processing is presumed to involve widespread activation of the autonomic nervous system. If this is the case, we might expect to see similar effects on all local vs. global task comparisons. To test this hypothesis, we asked whether chromatic cues also influence performance in tasks involving low level visual feature integration. Methods: Subjects performed either local (contrast detection) or global (form detection) tasks on achromatic dynamic Glass pattern stimuli. Coloured instructions, target frames and fixation points were used to attempt to bias performance to different task types. Based on previous literature, we hypothesised that red cues would improve performance in the (local) contrast detection task but would impede performance in the (global) form detection task.  Results: A two-way, repeated measures, analysis of covariance (2×2 ANCOVA) with gender as a covariate, revealed no influence of colour on either task, F(1,29) = 0.289, p = 0.595, partial η 2 = 0.002. Additional analysis revealed no significant differences in only the first attempts of the tasks or in the improvement in performance between trials. Discussion: We conclude that motivational processes elicited by colour perception do not influence neuronal signal processing in the early visual system, in stark contrast to their putative effects on processing in higher areas. PMID:25075280

No psychological effect of color context in a low level vision task.

PubMed

Pedley, Adam; Wade, Alex R

2013-01-01

A remarkable series of recent papers have shown that colour can influence performance in cognitive tasks. In particular, they suggest that viewing a participant number printed in red ink or other red ancillary stimulus elements improves performance in tasks requiring local processing and impedes performance in tasks requiring global processing whilst the reverse is true for the colour blue. The tasks in these experiments require high level cognitive processing such as analogy solving or remote association tests and the chromatic effect on local vs. global processing is presumed to involve widespread activation of the autonomic nervous system. If this is the case, we might expect to see similar effects on all local vs. global task comparisons. To test this hypothesis, we asked whether chromatic cues also influence performance in tasks involving low level visual feature integration. Subjects performed either local (contrast detection) or global (form detection) tasks on achromatic dynamic Glass pattern stimuli. Coloured instructions, target frames and fixation points were used to attempt to bias performance to different task types. Based on previous literature, we hypothesised that red cues would improve performance in the (local) contrast detection task but would impede performance in the (global) form detection task.  A two-way, repeated measures, analysis of covariance (2×2 ANCOVA) with gender as a covariate, revealed no influence of colour on either task, F(1,29) = 0.289, p = 0.595, partial η (2) = 0.002. Additional analysis revealed no significant differences in only the first attempts of the tasks or in the improvement in performance between trials. We conclude that motivational processes elicited by colour perception do not influence neuronal signal processing in the early visual system, in stark contrast to their putative effects on processing in higher areas.

Faculty development and organizational systems behavior.

PubMed

Henley, C E; Magelssen, D

1990-06-01

Faculty development is that process that fosters improvement in faculty members' skills in teaching and research and promotes their career advancement. This study investigated the association between organizational behavior in military medical centers and the faculty development of its medical corps officers assigned to teaching positions. Such organizational behaviors as defining tasks clearly and resolving conflicts satisfactorily correlated well with the faculty members' overall satisfaction and other parameters of good faculty development. The results suggest that a strong relationship exists between the organizational behavior of an institution and the sense of identity, productivity, and continued career growth of its individual faculty members.

Perceptual and conceptual information processing in schizophrenia and depression.

PubMed

Dreben, E K; Fryer, J H; McNair, D M

1995-04-01

Schizophrenic patients (n = 20), depressive patients (n = 20), and normal adults (n = 20) were compared on global vs local analyses of perceptual information using tachistoscopic tasks and on top-down vs bottom-up conceptual processing using card-sort tasks. The schizophrenic group performed more poorly on tasks requiring either global analyses (counting lines when distracting circles were present) or top-down conceptual processing (rule learning) than they did on tasks requiring local analyses (counting heterogeneous lines) or bottom-up processing (attribute identification). The schizophrenic group appeared not to use conceptually guided processing. Normal adults showed the reverse pattern. The depressive group performed similarly to the schizophrenic group on perceptual tasks but closer to the normal group on conceptual tasks, thereby appearing to be less dependent on a particular information-processing strategy. These deficits in organizational strategy may be related to the use of available processing resources as well as the allocation of attention.

When underadditivity of factor effects in the Psychological Refractory Period paradigm implies a bottleneck: evidence from psycholinguistics.

PubMed

Besner, Derek; Reynolds, Mike; O'Malley, Shannon

2009-11-01

The Psychological Refractory Period (PRP) paradigm is a dual-task procedure that can be used to examine the resource demands of specific cognitive processes. Inferences about the underlying processes are typically based on performance in the second of two speeded tasks. If the effect of a factor manipulated in Task 2 decreases as the stimulus onset asynchrony (SOA) between tasks decreases (underadditivity), the normative inference is that the effect of this factor occurs prior to a limited-capacity central processing mechanism. In contrast, if the effect of a factor is additive with SOA then the inference is that this indexes a process that either uses a limited-capacity central processing mechanism or occurs after some process that uses this mechanism. A heretofore unidentified exception to this logic arises when Task 2 involves two separate processes that operate in parallel, but compete. Interference with one process in Task 2 because of work on Task 1 will eliminate or reduce competition within Task 2 and is hence manifest as an underadditive interaction with decreasing SOA. This is illustrated here by reference to a PRP experiment in which the ubiquitous effect of spelling-to-sound regularity on reading aloud time is eliminated at a short SOA and by consideration of three converging lines of investigation in the PRP paradigm when Task 2 involves reading aloud.

The effect of processing code, response modality and task difficulty on dual task performance and subjective workload in a manual system

NASA Technical Reports Server (NTRS)

Liu, Yili; Wickens, Christopher D.

1987-01-01

This paper reports on the first experiment of a series studying the effect of task structure and difficulty demand on time-sharing performance and workload in both automated and corresponding manual systems. The experimental task involves manual control time-shared with spatial and verbal decisions tasks of two levels of difficulty and two modes of response (voice or manual). The results provide strong evidence that tasks and processes competing for common processing resources are time shared less effecively and have higher workload than tasks competing for separate resources. Subjective measures and the structure of multiple resources are used in conjunction to predict dual task performance. The evidence comes from both single-task and from dual-task performance.

Process Writing and Communicative-Task-Based Instruction: Many Common Features, but More Common Limitations?

ERIC Educational Resources Information Center

Bruton, Anthony

2005-01-01

Process writing and communicative-task-based instruction both assume productive tasks that prompt self-expression to motivate students and as the principal engine for developing L2 proficiency in the language classroom. Besides this, process writing and communicative-task-based instruction have much else in common, despite some obvious…

Neuroanatomical correlates of encoding in episodic memory: levels of processing effect.

PubMed Central

Kapur, S; Craik, F I; Tulving, E; Wilson, A A; Houle, S; Brown, G M

1994-01-01

Cognitive studies of memory processes demonstrate that memory for stimuli is a function of how they are encoded; stimuli processed semantically are better remembered than those processed in a perceptual or shallow fashion. This study investigates the neural correlates of this cognitive phenomenon. Twelve subjects performed two different cognitive tasks on a series of visually presented nouns. In one task, subjects detected the presence or absence of the letter a; in the other, subjects categorized each noun as living or nonliving. Positron emission tomography (PET) scans using 15O-labeled water were obtained during both tasks. Subjects showed substantially better recognition memory for nouns seen in the living/nonliving task, compared to nouns seen in the a-checking task. Comparison of the PET images between the two cognitive tasks revealed a significant activation in the left inferior prefrontal cortex (Brodmann's areas 45, 46, 47, and 10) in the semantic task as compared to the perceptual task. We propose that memory processes are subserved by a wide neurocognitive network and that encoding processes involve preferential activation of the structures in the left inferior prefrontal cortex. PMID:8134340

Neuroanatomical correlates of encoding in episodic memory: levels of processing effect.

PubMed

Kapur, S; Craik, F I; Tulving, E; Wilson, A A; Houle, S; Brown, G M

1994-03-15

Cognitive studies of memory processes demonstrate that memory for stimuli is a function of how they are encoded; stimuli processed semantically are better remembered than those processed in a perceptual or shallow fashion. This study investigates the neural correlates of this cognitive phenomenon. Twelve subjects performed two different cognitive tasks on a series of visually presented nouns. In one task, subjects detected the presence or absence of the letter a; in the other, subjects categorized each noun as living or nonliving. Positron emission tomography (PET) scans using 15O-labeled water were obtained during both tasks. Subjects showed substantially better recognition memory for nouns seen in the living/nonliving task, compared to nouns seen in the a-checking task. Comparison of the PET images between the two cognitive tasks revealed a significant activation in the left inferior prefrontal cortex (Brodmann's areas 45, 46, 47, and 10) in the semantic task as compared to the perceptual task. We propose that memory processes are subserved by a wide neurocognitive network and that encoding processes involve preferential activation of the structures in the left inferior prefrontal cortex.

Training, Retention, and Transfer of Data Entry Perceptual and Motoric Processes Over Long Retention Intervals

NASA Technical Reports Server (NTRS)

Kole, James A.; Schneider, Vivian I.; Healy, Alice F.; Barshi, Immanuel

2017-01-01

Subjects trained in a standard data entry task, which involved typing numbers (e.g., 5421) using their right hands. At test (6 months post-training), subjects completed the standard task, followed by a left-hand variant (typing with their left hands) that involved the same perceptual, but different motoric, processes as the standard task. At a second test (8 months post-training), subjects completed the standard task, followed by a code variant (translating letters into digits, then typing the digits with their right hands) that involved different perceptual, but the same motoric, processes as the standard task. For each of the three tasks, half the trials were trained numbers (old) and half were new. Repetition priming (faster response times to old than new numbers) was found for each task. Repetition priming for the standard task reflects retention of trained numbers; for the left-hand variant reflects transfer of perceptual processes; and for the code variant reflects transfer of motoric processes. There was thus evidence for both specificity and generalizability of training data entry perceptual and motoric processes over very long retention intervals.

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

PubMed

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.

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

PubMed Central

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

Global-local processing relates to spatial and verbal processing: implications for sex differences in cognition.

PubMed

Pletzer, Belinda; Scheuringer, Andrea; Scherndl, Thomas

2017-09-05

Sex differences have been reported for a variety of cognitive tasks and related to the use of different cognitive processing styles in men and women. It was recently argued that these processing styles share some characteristics across tasks, i.e. male approaches are oriented towards holistic stimulus aspects and female approaches are oriented towards stimulus details. In that respect, sex-dependent cognitive processing styles share similarities with attentional global-local processing. A direct relationship between cognitive processing and global-local processing has however not been previously established. In the present study, 49 men and 44 women completed a Navon paradigm and a Kimchi Palmer task as well as a navigation task and a verbal fluency task with the goal to relate the global advantage (GA) effect as a measure of global processing to holistic processing styles in both tasks. Indeed participants with larger GA effects displayed more holistic processing during spatial navigation and phonemic fluency. However, the relationship to cognitive processing styles was modulated by the specific condition of the Navon paradigm, as well as the sex of participants. Thus, different types of global-local processing play different roles for cognitive processing in men and women.

Relating Androgen Receptor Conformation to Function in Prostate Cancer Cells

DTIC Science & Technology

2005-01-01

line development , but have made progress towards resolving these issues and in development of alternate strategies. Task 1. Development of AR and...conformation. Task 2. Development of LNCaP Cells to Express Human AR mutants. We experienced unexpected difficulties in Task 2. We transfected the TET...Coactivators in AR Transactivation Summary Androgens drive sex differentiation, bone and muscle development , and promote growth of hormone dependent cancers

An investigation into semantic and phonological processing in individuals with Williams syndrome.

PubMed

Lee, Cheryl S; Binder, Katherine S

2014-02-01

The current study examined semantic and phonological processing in individuals with Williams syndrome (WS). Previous research in language processing in individuals with WS suggests a complex linguistic system characterized by "deviant" semantic organization and differential phonological processing. Two experiments explored these representations in individuals with WS. The first experiment analyzed the relative typicality and frequency of participants' responses to a semantic and phonological fluency task. The second experiment tapped into online language processing through a semantic priming task and an online sentence reading task measuring the effects of word frequency. Thirteen participants with WS were matched to a group of participants on reading grade level and a group of participants on chronological age. The results of the semantic fluency task, semantic priming task, and word frequency task suggest that semantic organization in individuals with WS appears commensurate with their reading level rather than deviant. The pattern of results suggests that individuals with WS do not appear to have deviant semantic organization, while confirming that online tasks that tap into these processes are a promising direction in investigations that include atypically developing populations. These findings for the phonological tasks warrant further research into phonological processing in individuals with WS.

An architecture for real-time vision processing

NASA Technical Reports Server (NTRS)

Chien, Chiun-Hong

1994-01-01

To study the feasibility of developing an architecture for real time vision processing, a task queue server and parallel algorithms for two vision operations were designed and implemented on an i860-based Mercury Computing System 860VS array processor. The proposed architecture treats each vision function as a task or set of tasks which may be recursively divided into subtasks and processed by multiple processors coordinated by a task queue server accessible by all processors. Each idle processor subsequently fetches a task and associated data from the task queue server for processing and posts the result to shared memory for later use. Load balancing can be carried out within the processing system without the requirement for a centralized controller. The author concludes that real time vision processing cannot be achieved without both sequential and parallel vision algorithms and a good parallel vision architecture.

Mobil Solar Energy Corporation thin EFG octagons. Semiannual subcontract report, 1 April 1992--30 September 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalejs, J.P.

1993-09-01

This report describes work carried out for the PVMaT program at Mobil Solar for the period covering April 1, 1992, to September 30, 1992. Mobil Solar is developing advanced technology for growing and cutting 200-{mu}m-thick edge-defined film-fed growth (EFG) octagon tubes that will reduce the manufacturing costs of 10-cm {times} 10-cm polycrystalline EFG silicon wafers. Mobil Solar has made progress in identifying factors that impact on thickness nonuniformity and means to reduce the deleterious impact of ambient-related effects that have caused reduction in crystal growth productivity and wafer yield. The current main obstacle to meeting material yield targets arises duemore » to the buckling produced by thermal stress. Studies of laser cutting of EFG silicon using ND:YAG and dye lasers are underway to develop reduced damage cutting methods. Mobil Solar has carried out design reviews for crystal growth and laser cutting equipment. A task has been initiated to evaluate new online sensors for crystal growth process control and to study implementation of advanced control concepts for productivity and yield improvements.« less

Branching out: origins of the sea urchin larval skeleton in development and evolution.

PubMed

McIntyre, Daniel C; Lyons, Deirdre C; Martik, Megan; McClay, David R

2014-03-01

It is a challenge to understand how the information encoded in DNA is used to build a three-dimensional structure. To explore how this works the assembly of a relatively simple skeleton has been examined at multiple control levels. The skeleton of the sea urchin embryo consists of a number of calcite rods produced by 64 skeletogenic cells. The ectoderm supplies spatial cues for patterning, essentially telling the skeletogenic cells where to position themselves and providing the factors for skeletal growth. Here, we describe the information known about how this works. First the ectoderm must be patterned so that the signaling cues are released from precise positions. The skeletogenic cells respond by initiating skeletogenesis immediately beneath two regions (one on the right and the other on the left side). Growth of the skeletal rods requires additional signaling from defined ectodermal locations, and the skeletogenic cells respond to produce a membrane-bound template in which the calcite crystal grows. Important in this process are three signals, fibroblast growth factor, vascular endothelial growth factor, and Wnt5. Each is necessary for explicit tasks in skeleton production. Copyright © 2014 Wiley Periodicals, Inc.

Selective impairment of masked priming in dual-task performance.

PubMed

Fischer, Rico; Kiesel, Andrea; Kunde, Wilfried; Schubert, Torsten

2011-03-01

This study investigated the impact of divided attention on masked priming. In a dual-task setting, two tasks had to be carried out in close temporal succession: a tone discrimination task and a masked priming task. The order of the tasks was varied between experiments, and attention was always allocated to the first task-that is, the first task was prioritized. The priming task was the second (nonprioritized) task in Experiment 1 and the first (prioritized) task in Experiment 2. In both experiments, "novel" prime stimuli associated with semantic processing were essentially ineffective. However, there was intact priming by another type of prime stimuli associated with response priming. Experiment 3 showed that all these prime stimuli can reveal significant priming effects during a task-switching paradigm in which both tasks were performed consecutively. We conclude that dual-task specific interference processes (e.g., the simultaneous coordination of multiple stimulus-response rules) selectively impair priming that is assumed to rely on semantic processing.

Dealing with prospective memory demands while performing an ongoing task: Shared processing, increased on-task focus, or both?

PubMed

Rummel, Jan; Smeekens, Bridget A; Kane, Michael J

2017-07-01

Prospective memory (PM) is the cognitive ability to remember to fulfill intended action plans at the appropriate future moment. Current theories assume that PM fulfillment draws on attentional processes. Accordingly, pending PM intentions interfere with other ongoing tasks to the extent to which both tasks rely on the same processes. How do people manage the competition between PM and ongoing-task demands? Based on research relating mind wandering and attentional control (Kane & McVay, 2012), we argue that people may not only change the way they process ongoing-task stimuli when given a PM intention, but they may also engage in less off-task thinking than they otherwise would. That is, people focus more strongly on the tasks at hand and dedicate considerable conscious thought to the PM goal. We tested this hypothesis by asking subjects to periodically report on their thoughts during prototypical PM (and control) tasks. Task-unrelated thought rates dropped when participants performed an ongoing task while holding a PM intention versus performing the ongoing task alone (Experiment 1), even when PM demands were minimized (Experiment 2) and more so when PM execution was especially rewarded (Experiment 3). Our findings suggest that PM demands not only elicit a cost to ongoing-task processing, but they also induce a stronger on-task focus and promote conscious thoughts about the PM intention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Processing of pitch and location in human auditory cortex during visual and auditory tasks.

PubMed

Häkkinen, Suvi; Ovaska, Noora; Rinne, Teemu

2015-01-01

The relationship between stimulus-dependent and task-dependent activations in human auditory cortex (AC) during pitch and location processing is not well understood. In the present functional magnetic resonance imaging study, we investigated the processing of task-irrelevant and task-relevant pitch and location during discrimination, n-back, and visual tasks. We tested three hypotheses: (1) According to prevailing auditory models, stimulus-dependent processing of pitch and location should be associated with enhanced activations in distinct areas of the anterior and posterior superior temporal gyrus (STG), respectively. (2) Based on our previous studies, task-dependent activation patterns during discrimination and n-back tasks should be similar when these tasks are performed on sounds varying in pitch or location. (3) Previous studies in humans and animals suggest that pitch and location tasks should enhance activations especially in those areas that also show activation enhancements associated with stimulus-dependent pitch and location processing, respectively. Consistent with our hypotheses, we found stimulus-dependent sensitivity to pitch and location in anterolateral STG and anterior planum temporale (PT), respectively, in line with the view that these features are processed in separate parallel pathways. Further, task-dependent activations during discrimination and n-back tasks were associated with enhanced activations in anterior/posterior STG and posterior STG/inferior parietal lobule (IPL) irrespective of stimulus features. However, direct comparisons between pitch and location tasks performed on identical sounds revealed no significant activation differences. These results suggest that activations during pitch and location tasks are not strongly affected by enhanced stimulus-dependent activations to pitch or location. We also found that activations in PT were strongly modulated by task requirements and that areas in the inferior parietal lobule (IPL) showed task-dependent activation modulations, but no systematic activations to pitch or location. Based on these results, we argue that activations during pitch and location tasks cannot be explained by enhanced stimulus-specific processing alone, but rather that activations in human AC depend in a complex manner on the requirements of the task at hand.

Processing of pitch and location in human auditory cortex during visual and auditory tasks

PubMed Central

Häkkinen, Suvi; Ovaska, Noora; Rinne, Teemu

2015-01-01

The relationship between stimulus-dependent and task-dependent activations in human auditory cortex (AC) during pitch and location processing is not well understood. In the present functional magnetic resonance imaging study, we investigated the processing of task-irrelevant and task-relevant pitch and location during discrimination, n-back, and visual tasks. We tested three hypotheses: (1) According to prevailing auditory models, stimulus-dependent processing of pitch and location should be associated with enhanced activations in distinct areas of the anterior and posterior superior temporal gyrus (STG), respectively. (2) Based on our previous studies, task-dependent activation patterns during discrimination and n-back tasks should be similar when these tasks are performed on sounds varying in pitch or location. (3) Previous studies in humans and animals suggest that pitch and location tasks should enhance activations especially in those areas that also show activation enhancements associated with stimulus-dependent pitch and location processing, respectively. Consistent with our hypotheses, we found stimulus-dependent sensitivity to pitch and location in anterolateral STG and anterior planum temporale (PT), respectively, in line with the view that these features are processed in separate parallel pathways. Further, task-dependent activations during discrimination and n-back tasks were associated with enhanced activations in anterior/posterior STG and posterior STG/inferior parietal lobule (IPL) irrespective of stimulus features. However, direct comparisons between pitch and location tasks performed on identical sounds revealed no significant activation differences. These results suggest that activations during pitch and location tasks are not strongly affected by enhanced stimulus-dependent activations to pitch or location. We also found that activations in PT were strongly modulated by task requirements and that areas in the inferior parietal lobule (IPL) showed task-dependent activation modulations, but no systematic activations to pitch or location. Based on these results, we argue that activations during pitch and location tasks cannot be explained by enhanced stimulus-specific processing alone, but rather that activations in human AC depend in a complex manner on the requirements of the task at hand. PMID:26594185

Processing Demands Impact 3-Year-Olds' Performance in a Spontaneous-Response Task: New Evidence for the Processing-Load Account of Early False-Belief Understanding.

PubMed

Scott, Rose M; Roby, Erin

2015-01-01

Prior to age four, children succeed in non-elicited-response false-belief tasks but fail elicited-response false-belief tasks. To explain this discrepancy, the processing-load account argues that the capacity to represent beliefs emerges in infancy, as indicated by early success on non-elicited-response tasks, but that children's ability to demonstrate this capacity depends on the processing demands of the task and children's processing skills. When processing demands exceed young children's processing abilities, such as in standard elicited-response tasks, children fail despite their capacity to represent beliefs. Support for this account comes from recent evidence that reducing processing demands improves young children's performance: when demands are sufficiently reduced, 2.5-year-olds succeed in elicited-response tasks. Here we sought complementary evidence for the processing-load account by examining whether increasing processing demands impeded children's performance in a non-elicited-response task. 3-year-olds were tested in a preferential-looking task in which they heard a change-of-location false-belief story accompanied by a picture book; across children, we manipulated the amount of linguistic ambiguity in the story. The final page of the book showed two images: one that was consistent with the main character's false belief and one that was consistent with reality. When the story was relatively unambiguous, children looked reliably longer at the false-belief-consistent image, successfully demonstrating their false-belief understanding. When the story was ambiguous, however, this undermined children's performance: looking times to the belief-consistent image were correlated with verbal ability, and only children with verbal skills in the upper quartile of the sample demonstrated a significant preference for the belief-consistent image. These results support the processing-load account by demonstrating that regardless of whether a task involves an elicited response, children's performance depends on the processing demands of the task and their processing skills. These findings also have implications for alternative, deflationary accounts of early false-belief understanding.

Processing Demands Impact 3-Year-Olds’ Performance in a Spontaneous-Response Task: New Evidence for the Processing-Load Account of Early False-Belief Understanding

PubMed Central

Scott, Rose M.; Roby, Erin

2015-01-01

Prior to age four, children succeed in non-elicited-response false-belief tasks but fail elicited-response false-belief tasks. To explain this discrepancy, the processing-load account argues that the capacity to represent beliefs emerges in infancy, as indicated by early success on non-elicited-response tasks, but that children’s ability to demonstrate this capacity depends on the processing demands of the task and children’s processing skills. When processing demands exceed young children’s processing abilities, such as in standard elicited-response tasks, children fail despite their capacity to represent beliefs. Support for this account comes from recent evidence that reducing processing demands improves young children’s performance: when demands are sufficiently reduced, 2.5-year-olds succeed in elicited-response tasks. Here we sought complementary evidence for the processing-load account by examining whether increasing processing demands impeded children’s performance in a non-elicited-response task. 3-year-olds were tested in a preferential-looking task in which they heard a change-of-location false-belief story accompanied by a picture book; across children, we manipulated the amount of linguistic ambiguity in the story. The final page of the book showed two images: one that was consistent with the main character’s false belief and one that was consistent with reality. When the story was relatively unambiguous, children looked reliably longer at the false-belief-consistent image, successfully demonstrating their false-belief understanding. When the story was ambiguous, however, this undermined children’s performance: looking times to the belief-consistent image were correlated with verbal ability, and only children with verbal skills in the upper quartile of the sample demonstrated a significant preference for the belief-consistent image. These results support the processing-load account by demonstrating that regardless of whether a task involves an elicited response, children’s performance depends on the processing demands of the task and their processing skills. These findings also have implications for alternative, deflationary accounts of early false-belief understanding. PMID:26562840

Two-and-a-half-year-olds succeed at a traditional false-belief task with reduced processing demands.

PubMed

Setoh, Peipei; Scott, Rose M; Baillargeon, Renée

2016-11-22

When tested with traditional false-belief tasks, which require answering a standard question about the likely behavior of an agent with a false belief, children perform below chance until age 4 y or later. When tested without such questions, however, children give evidence of false-belief understanding much earlier. Are traditional tasks difficult because they tap a more advanced form of false-belief understanding (fundamental-change view) or because they impose greater processing demands (processing-demands view)? Evidence that young children succeed at traditional false-belief tasks when processing demands are reduced would support the latter view. In prior research, reductions in inhibitory-control demands led to improvements in young children's performance, but often only to chance (instead of below-chance) levels. Here we examined whether further reductions in processing demands might lead to success. We speculated that: (i) young children could respond randomly in a traditional low-inhibition task because their limited information-processing resources are overwhelmed by the total concurrent processing demands in the task; and (ii) these demands include those from the response-generation process activated by the standard question. This analysis suggested that 2.5-y-old toddlers might succeed at a traditional low-inhibition task if response-generation demands were also reduced via practice trials. As predicted, toddlers performed above chance following two response-generation practice trials; toddlers failed when these trials either were rendered less effective or were used in a high-inhibition task. These results support the processing-demands view: Even toddlers succeed at a traditional false-belief task when overall processing demands are reduced.

Dual-Task Interference When A Response is Not Required

NASA Technical Reports Server (NTRS)

VanSelst, Mark; Johnston, James C.; Shafto, Michael (Technical Monitor)

2002-01-01

When subjects are required to respond to two stimuli presented in rapid succession, responses to the second stimulus are delayed. Such dual-task interference has been attributed to a fundamental processing bottleneck preventing simultaneous processing on both tasks. Two experiments show dual-task interference even when the first task does not require a response. The observed interference is caused by a bottleneck in central cognitive processing, rather than in response initiation or execution.

Out with the Old and in with the New—Is Backward Inhibition a Domain-Specific Process?

PubMed Central

Menghini, Deny; Vicari, Stefano; Petrosini, Laura; Ferlazzo, Fabio

2015-01-01

Effective task switching is supported by the inhibition of the just executed task, so that potential interference from previously executed tasks is adaptively counteracted. This inhibitory mechanism, named Backward Inhibition (BI), has been inferred from the finding that switching back to a recently executed task (A-B-A task sequence) is harder than switching back to a less recently executed task (C-B-A task sequence). Despite the fact that BI effects do impact performance on everyday life activities, up to now it is still not clear whether the BI represents an amodal and material-independent process or whether it interacts with the task material. To address this issue, a group of individuals with Williams syndrome (WS) characterized by specific difficulties in maintaining and processing visuo-spatial, but not verbal, information, and a mental age- and gender-matched group of typically developing (TD) children were subjected to three task-switching experiments requiring verbal or visuo-spatial material to be processed. Results showed that individuals with WS exhibited a normal BI effect during verbal task-switching, but a clear deficit during visuo-spatial task-switching. Overall, our findings demonstrating that the BI is a material-specific process have important implications for theoretical models of cognitive control and its architecture. PMID:26565628

A Technical Survey on Optimization of Processing Geo Distributed Data

NASA Astrophysics Data System (ADS)

Naga Malleswari, T. Y. J.; Ushasukhanya, S.; Nithyakalyani, A.; Girija, S.

2018-04-01

With growing cloud services and technology, there is growth in some geographically distributed data centers to store large amounts of data. Analysis of geo-distributed data is required in various services for data processing, storage of essential information, etc., processing this geo-distributed data and performing analytics on this data is a challenging task. The distributed data processing is accompanied by issues in storage, computation and communication. The key issues to be dealt with are time efficiency, cost minimization, utility maximization. This paper describes various optimization methods like end-to-end multiphase, G-MR, etc., using the techniques like Map-Reduce, CDS (Community Detection based Scheduling), ROUT, Workload-Aware Scheduling, SAGE, AMP (Ant Colony Optimization) to handle these issues. In this paper various optimization methods and techniques used are analyzed. It has been observed that end-to end multiphase achieves time efficiency; Cost minimization concentrates to achieve Quality of Service, Computation and reduction of Communication cost. SAGE achieves performance improvisation in processing geo-distributed data sets.

High-School Students' Reasoning while Constructing Plant Growth Models in a Computer-Supported Educational Environment. Research Report

ERIC Educational Resources Information Center

Ergazaki, Marida; Komis, Vassilis; Zogza, Vassiliki

2005-01-01

This paper highlights specific aspects of high-school students' reasoning while coping with a modeling task of plant growth in a computer-supported educational environment. It is particularly concerned with the modeling levels ('macro-phenomenological' and 'micro-conceptual' level) activated by peers while exploring plant growth and with their…

Modeling individual tree growth by fusing diameter tape and increment core data

Treesearch

Erin M. Schliep; Tracy Qi Dong; Alan E. Gelfand; Fan. Li

2014-01-01

Tree growth estimation is a challenging task as difficulties associated with data collection and inference often result in inaccurate estimates. Two main methods for tree growth estimation are diameter tape measurements and increment cores. The former involves repeatedly measuring tree diameters with a cloth or metal tape whose scale has been adjusted to give diameter...

Dual-task interference effects on cross-modal numerical order and sound intensity judgments: the more the louder?

PubMed

Alards-Tomalin, Doug; Walker, Alexander C; Nepon, Hillary; Leboe-McGowan, Launa C

2017-09-01

In the current study, cross-task interactions between number order and sound intensity judgments were assessed using a dual-task paradigm. Participants first categorized numerical sequences composed of Arabic digits as either ordered (ascending, descending) or non-ordered. Following each number sequence, participants then had to judge the intensity level of a target sound. Experiment 1 emphasized processing the two tasks independently (serial processing), while Experiments 2 and 3 emphasized processing the two tasks simultaneously (parallel processing). Cross-task interference occurred only when the task required parallel processing and was specific to ascending numerical sequences, which led to a higher proportion of louder sound intensity judgments. In Experiment 4 we examined whether this unidirectional interaction was the result of participants misattributing enhanced processing fluency experienced on ascending sequences as indicating a louder target sound. The unidirectional finding could not be entirely attributed to misattributed processing fluency, and may also be connected to experientially derived conceptual associations between ascending number sequences and greater magnitude, consistent with conceptual mapping theory.

Context-Sensitive Adjustment of Cognitive Control in Dual-Task Performance

ERIC Educational Resources Information Center

Fischer, Rico; Gottschalk, Caroline; Dreisbach, Gesine

2014-01-01

Performing 2 highly similar tasks at the same time requires an adaptive regulation of cognitive control to shield prioritized primary task processing from between-task (cross-talk) interference caused by secondary task processing. In the present study, the authors investigated how implicitly and explicitly delivered information promotes the…

The Influence of Levels of Processing on Recall from Working Memory and Delayed Recall Tasks

ERIC Educational Resources Information Center

Loaiza, Vanessa M.; McCabe, David P.; Youngblood, Jessie L.; Rose, Nathan S.; Myerson, Joel

2011-01-01

Recent research in working memory has highlighted the similarities involved in retrieval from complex span tasks and episodic memory tasks, suggesting that these tasks are influenced by similar memory processes. In the present article, the authors manipulated the level of processing engaged when studying to-be-remembered words during a reading…

Dual-task performance with ideomotor-compatible tasks: is the central processing bottleneck intact, bypassed, or shifted in locus?

NASA Technical Reports Server (NTRS)

Lien, Mei-Ching; McCann, Robert S.; Ruthruff, Eric; Proctor, Robert W.

2005-01-01

The present study examined whether the central bottleneck, assumed to be primarily responsible for the psychological refractory period (PRP) effect, is intact, bypassed, or shifted in locus with ideomotor (IM)-compatible tasks. In 4 experiments, factorial combinations of IM- and non-IM-compatible tasks were used for Task 1 and Task 2. All experiments showed substantial PRP effects, with a strong dependency between Task 1 and Task 2 response times. These findings, along with model-based simulations, indicate that the processing bottleneck was not bypassed, even with two IM-compatible tasks. Nevertheless, systematic changes in the PRP and correspondence effects across experiments suggest that IM compatibility shifted the locus of the bottleneck. The findings favor an engage-bottleneck-later hypothesis, whereby parallelism between tasks occurs deeper into the processing stream for IM- than for non-IM-compatible tasks, without the bottleneck being actually eliminated.

Acute physical exercise affected processing efficiency in an auditory attention task more than processing effectiveness.

PubMed

Dutke, Stephan; Jaitner, Thomas; Berse, Timo; Barenberg, Jonathan

2014-02-01

Research on effects of acute physical exercise on performance in a concurrent cognitive task has generated equivocal evidence. Processing efficiency theory predicts that concurrent physical exercise can increase resource requirements for sustaining cognitive performance even when the level of performance is unaffected. This hypothesis was tested in a dual-task experiment. Sixty young adults worked on a primary auditory attention task and a secondary interval production task while cycling on a bicycle ergometer. Physical load (cycling) and cognitive load of the primary task were manipulated. Neither physical nor cognitive load affected primary task performance, but both factors interacted on secondary task performance. Sustaining primary task performance under increased physical and/or cognitive load increased resource consumption as indicated by decreased secondary task performance. Results demonstrated that physical exercise effects on cognition might be underestimated when only single task performance is the focus.

Cue response dissociates inhibitory processes: task identity information is related to backward inhibition but not to competitor rule suppression.

PubMed

Regev, Shirley; Meiran, Nachshon

2017-01-01

In task switching, a conflict between competing task-sets is resolved by inhibiting the interfering task-set. Recent models have proposed a framework of the task-set as composed of two hierarchical components: abstract task identity (e.g., respond to quantity) and more concrete task rules (e.g., category-response rules mapping the categories "one" and "three" to the left and right keys, respectively). The present study explored whether task-set inhibition is the outcome of a general control process or whether it reflects multiple inhibitory processes, each targeting a different component of the competing task-set. To this end, two effects of task-set inhibition were examined: backward inhibition (BI), reflecting the suppression of a just-performed task-set that is no longer relevant; and, competitor rule suppression (CRS), reflecting the suppression of an irrelevant task-set that generates a response conflict. In two task switching experiments, each involving three tasks, we asked participants to make two responses: a cue response, indicating the identity of the relevant task (e.g., "Color"), and a target response requiring the implementation of the task rule (e.g., "Red"). The results demonstrate that BI, but not CRS, appears in cue responses, and thus, suggests that BI reflects inhibition that influences representations related to abstract task identity, rather than (just) competing responses or response rules. These results support a dissociation between inhibitory processes in task switching. The current findings also provide further evidence for a multi-component conceptualization of task-set and task-set inhibition.

Dip-coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Zook, J. D.; Heaps, J. D.; Maciolek, R. B.; Koepke, B. G.; Gutter, C. D.; Schuldt, S. B.

1977-01-01

The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. The past quarter demonstrated significant progress in several areas. Seeded growth of silicon-on-ceramic (SOC) with an EFG ribbon seed was demonstrated. Different types of mullite were successfully coated with silicon. A new method of deriving minority carrier diffusion length, L sub n from spectral response measurements was evaluated. ECOMOD cost projections were found to be in good agreement with the interim SAMIS method proposed by JPL. On the less positive side, there was a decrease in cell performance which we believe to be due to an unidentified source of impurities.

Stages of functional processing and the bihemispheric recognition of Japanese Kana script.

PubMed

Yoshizaki, K

2000-04-01

Two experiments were carried out in order to examine the effects of functional steps on the benefits of interhemispheric integration. The purpose of Experiment 1 was to investigate the validity of the Banich (1995a) model, where the benefits of interhemispheric processing increase as the task involves more functional steps. The 16 right-handed subjects were given two types of Hiragana-Katakana script matching tasks. One was the Name Identity (NI) task, and the other was the vowel matching (VM) task, which involved more functional steps compared to the NI task. The VM task required subjects to make a decision whether or not a pair of Katakana-Hiragana scripts had a common vowel. In both tasks, a pair of Kana scripts (Katakana-Hiragana scripts) was tachistoscopically presented in the unilateral visual fields or the bilateral visual fields, where each letter was presented in each visual field. A bilateral visual fields advantage (BFA) was found in both tasks, and the size of this did not differ between the tasks, suggesting that these findings did not support the Banich model. The purpose of Experiment 2 was to examine the effects of imbalanced processing load between the hemispheres on the benefits of interhemispheric integration. In order to manipulate the balance of processing load across the hemispheres, the revised vowel matching (r-VM) task was developed by amending the VM task. The r-VM task was the same as the VM task in Experiment 1, except that a script that has only vowel sound was presented as a counterpart of a pair of Kana scripts. The 24 right-handed subjects were given the r-VM and NI tasks. The results showed that although a BFA showed up in the NI task, it did not in the r-VM task. These results suggested that the balance of processing load between hemispheres would have an influence on the bilateral hemispheric processing.

Adult age differences in the storage of information in working memory.

PubMed

Foos, P W; Wright, L

1992-01-01

The performance of 97 young and 91 old persons were compared to determine if a deficiency in working memory resources for processing, storage, or allocation could be detected. Persons simultaneously performed a storage and one of two processing tasks while instructed to allocate resources to processing, storage, or both tasks. The storage task involved remembering the names of one, three, or five persons. Processing tasks involved solving addition problems presented on flashcards or answering common knowledge questions. Results showed increased age differences on the storage task as demands for resources increased but no differences on processing tasks. Individuals seemed unable to allocate resources as instructed. A comparison of young-old and old-old groups showed the same results as those obtained comparing young and old groups and support the hypothesis of a deficiency of storage, but not processing, resources in working memory for old, especially old-old, adults.

Conflict-specific effects of accessory stimuli on cognitive control in the Stroop task and the Simon task.

PubMed

Soutschek, Alexander; Müller, Hermann J; Schubert, Torsten

2013-01-01

Both the Stroop and the Simon paradigms are often used in research on cognitive control, however, there is evidence that dissociable control processes are involved in these tasks: While conflicts in the Stroop task may be resolved mainly by enhanced task-relevant stimulus processing, conflicts in the Simon task may be resolved rather by suppressing the influence of task-irrelevant information on response selection. In the present study, we show that these control mechanisms interact in different ways with the presentation of accessory stimuli. Accessory stimuli do not affect cognitive control in the Simon task, but they impair the efficiency of cross-trial control processes in the Stroop task. Our findings underline the importance of differentiating between different types of conflicts and mechanisms of cognitive control.

Correlates of individual, and age-related, differences in short-term learning.

PubMed

Zhang, Zhiyong; Davis, Hasker P; Salthouse, Timothy A; Tucker-Drob, Elliot M

2007-07-01

Latent growth models were applied to data on multitrial verbal and spatial learning tasks from two independent studies. Although significant individual differences in both initial level of performance and subsequent learning were found in both tasks, age differences were found only in mean initial level, and not in mean learning. In neither task was fluid or crystallized intelligence associated with learning. Although there were moderate correlations among the level parameters across the verbal and spatial tasks, the learning parameters were not significantly correlated with one another across task modalities. These results are inconsistent with the existence of a general (e.g., material-independent) learning ability.

R&M (Reliability and Maintainability) Program Cost Drivers.

DTIC Science & Technology

1987-05-01

Specific data points used to develop the models (i.e., labor hours mid associated systems and task application characteristics) were obtained from three...study data base used to generate the CER’s em be expanded by adding project data points to the input data given in Appendix 13, adjusting the CER...FRACAS, worst-case/ thermal analyses, stress screening and R-growth. However, the studies did not assign benefits to specific task areas. c. Task

Evaluation of DCS III Transmission Alternatives, Phase II, Task 1.

DTIC Science & Technology

1981-08-31

Agency Defense Communications Engineering Center Reston, Virginia 22090 Contract No. DCA 100-79-C--0044 ,D ii 2 01982 ONG SPACI IAE K ROONOO IIACH...Transmission Media Alternatives Task 2. Development of Evolving DCS Transmission System Al ternatives Task 3. Identification of Technology and Regulatory...For existing tree growth, add 15 m. For smaller vegetation, add 3 m. 11. Determine the antenna tower heights to insure line-of-sight clearance above the

Development of L2 Interactional Resources for Online Collaborative Task Accomplishment

ERIC Educational Resources Information Center

Balaman, Ufuk; Sert, Olcay

2017-01-01

Technology-mediated task environments have long been considered integral parts of L2 learning and teaching processes. However, the interactional resources that the learners deploy to complete tasks in these environments have remained largely unexplored due to an overall focus on task design and outcomes rather than task engagement processes. With…

Dealing with Prospective Memory Demands While Performing an Ongoing Task: Shared Processing, Increased On-Task Focus, or Both?

ERIC Educational Resources Information Center

Rummel, Jan; Smeekens, Bridget A.; Kane, Michael J.

2017-01-01

Prospective memory (PM) is the cognitive ability to remember to fulfill intended action plans at the appropriate future moment. Current theories assume that PM fulfillment draws on attentional processes. Accordingly, pending PM intentions interfere with other ongoing tasks to the extent to which both tasks rely on the same processes. How do people…

Staying Mindful in Action: The Challenge of "Double Awareness" on Task and Process in an Action Lab

ERIC Educational Resources Information Center

Svalgaard, Lotte

2016-01-01

Action Learning is a well-proven method to integrate "task" and "process", as learning about team and self (process) takes place while delivering on a task or business challenge of real importance (task). An Action Lab® is an intensive Action Learning programme lasting for 5 days, which aims at balancing and integrating…

The Validity of Functional Near-Infrared Spectroscopy Recordings of Visuospatial Working Memory Processes in Humans.

PubMed

Witmer, Joëlle S; Aeschlimann, Eva A; Metz, Andreas J; Troche, Stefan J; Rammsayer, Thomas H

2018-04-05

Functional near infrared spectroscopy (fNIRS) is increasingly used for investigating cognitive processes. To provide converging evidence for the validity of fNIRS recordings in cognitive neuroscience, we investigated functional activation in the frontal cortex in 43 participants during the processing of a visuospatial working memory (WM) task and a sensory duration discrimination (DD) task functionally unrelated to WM. To distinguish WM-related processes from a general effect of increased task demand, we applied an adaptive approach, which ensured that subjective task demand was virtually identical for all individuals and across both tasks. Our specified region of interest covered Brodmann Area 8 of the left hemisphere, known for its important role in the execution of WM processes. Functional activation, as indicated by an increase of oxygenated and a decrease of deoxygenated hemoglobin, was shown for the WM task, but not in the DD task. The overall pattern of results indicated that hemodynamic responses recorded by fNIRS are sensitive to specific visuospatial WM capacity-related processes and do not reflect a general effect of increased task demand. In addition, the finding that no such functional activation could be shown for participants with far above-average mental ability suggested different cognitive processes adopted by this latter group.

The Validity of Functional Near-Infrared Spectroscopy Recordings of Visuospatial Working Memory Processes in Humans

PubMed Central

Witmer, Joëlle S.; Aeschlimann, Eva A.; Metz, Andreas J.; Rammsayer, Thomas H.

2018-01-01

Functional near infrared spectroscopy (fNIRS) is increasingly used for investigating cognitive processes. To provide converging evidence for the validity of fNIRS recordings in cognitive neuroscience, we investigated functional activation in the frontal cortex in 43 participants during the processing of a visuospatial working memory (WM) task and a sensory duration discrimination (DD) task functionally unrelated to WM. To distinguish WM-related processes from a general effect of increased task demand, we applied an adaptive approach, which ensured that subjective task demand was virtually identical for all individuals and across both tasks. Our specified region of interest covered Brodmann Area 8 of the left hemisphere, known for its important role in the execution of WM processes. Functional activation, as indicated by an increase of oxygenated and a decrease of deoxygenated hemoglobin, was shown for the WM task, but not in the DD task. The overall pattern of results indicated that hemodynamic responses recorded by fNIRS are sensitive to specific visuospatial WM capacity-related processes and do not reflect a general effect of increased task demand. In addition, the finding that no such functional activation could be shown for participants with far above-average mental ability suggested different cognitive processes adopted by this latter group. PMID:29621179

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

ERIC Educational Resources Information Center

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

2014-01-01

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

Lexical processing while deciding what task to perform: reading aloud in the context of the task set paradigm.

PubMed

O'Malley, Shannon; Besner, Derek

2011-12-01

The results of two experiments provide the first direct demonstration that subjects can process a word lexically despite concurrently being engaged in decoding a task cue telling them which of two tasks to perform. These results, taken together with others, point to qualitative differences between the mind's ability to engage in lexical versus sublexical processing during the time they are engaged with other tasks. The emerging picture is one in which some form of resource(s) plays little role during lexical processing whereas the need for some form of resource(s) during sublexical processing serves to bottleneck performance. Copyright © 2011 Elsevier Inc. All rights reserved.

Two-and-a-half-year-olds succeed at a traditional false-belief task with reduced processing demands

PubMed Central

Scott, Rose M.; Baillargeon, Renée

2016-01-01

When tested with traditional false-belief tasks, which require answering a standard question about the likely behavior of an agent with a false belief, children perform below chance until age 4 y or later. When tested without such questions, however, children give evidence of false-belief understanding much earlier. Are traditional tasks difficult because they tap a more advanced form of false-belief understanding (fundamental-change view) or because they impose greater processing demands (processing-demands view)? Evidence that young children succeed at traditional false-belief tasks when processing demands are reduced would support the latter view. In prior research, reductions in inhibitory-control demands led to improvements in young children’s performance, but often only to chance (instead of below-chance) levels. Here we examined whether further reductions in processing demands might lead to success. We speculated that: (i) young children could respond randomly in a traditional low-inhibition task because their limited information-processing resources are overwhelmed by the total concurrent processing demands in the task; and (ii) these demands include those from the response-generation process activated by the standard question. This analysis suggested that 2.5-y-old toddlers might succeed at a traditional low-inhibition task if response-generation demands were also reduced via practice trials. As predicted, toddlers performed above chance following two response-generation practice trials; toddlers failed when these trials either were rendered less effective or were used in a high-inhibition task. These results support the processing-demands view: Even toddlers succeed at a traditional false-belief task when overall processing demands are reduced. PMID:27821728

Checkpointing for a hybrid computing node

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cher, Chen-Yong

2016-03-08

According to an aspect, a method for checkpointing in a hybrid computing node includes executing a task in a processing accelerator of the hybrid computing node. A checkpoint is created in a local memory of the processing accelerator. The checkpoint includes state data to restart execution of the task in the processing accelerator upon a restart operation. Execution of the task is resumed in the processing accelerator after creating the checkpoint. The state data of the checkpoint are transferred from the processing accelerator to a main processor of the hybrid computing node while the processing accelerator is executing the task.

Cognitive abilities required in time judgment depending on the temporal tasks used: A comparison of children and adults.

PubMed

Droit-Volet, S; Wearden, J H; Zélanti, P S

2015-01-01

The aim of this study was to examine age-related differences in time judgments during childhood as a function of the temporal task used. Children aged 5 and 8 years, as well as adults, were submitted to 3 temporal tasks (bisection, generalization and reproduction) with short (0.4/0.8 s) and long durations (8/16 s). Furthermore, their cognitive capacities in terms of working memory, attentional control, and processing speed were assessed by a wide battery of neuropsychological tests. The results showed that the age-related differences in time judgment were greater in the reproduction task than in the temporal discrimination tasks. This task was indeed more demanding in terms of working memory and information processing speed. In addition, the bisection task appeared to be easier for children than the generalization task, whereas these 2 tasks were similar for the adults, although the generalization task required more attention to be paid to the processing of durations. Our study thus demonstrates that it is important to understand the different cognitive processes involved in time judgment as a function of the temporal tasks used before venturing to draw conclusions about the development of time perception capabilities.

Reward contingencies and the recalibration of task monitoring and reward systems: a high-density electrical mapping study.

PubMed

Morie, K P; De Sanctis, P; Foxe, J J

2014-07-25

Task execution almost always occurs in the context of reward-seeking or punishment-avoiding behavior. As such, ongoing task-monitoring systems are influenced by reward anticipation systems. In turn, when a task has been executed either successfully or unsuccessfully, future iterations of that task will be re-titrated on the basis of the task outcome. Here, we examined the neural underpinnings of the task-monitoring and reward-evaluation systems to better understand how they govern reward-seeking behavior. Twenty-three healthy adult participants performed a task where they accrued points that equated to real world value (gift cards) by responding as rapidly as possible within an allotted timeframe, while success rate was titrated online by changing the duration of the timeframe dependent on participant performance. Informative cues initiated each trial, indicating the probability of potential reward or loss (four levels from very low to very high). We manipulated feedback by first informing participants of task success/failure, after which a second feedback signal indicated actual magnitude of reward/loss. High-density electroencephalography (EEG) recordings allowed for examination of event-related potentials (ERPs) to the informative cues and in turn, to both feedback signals. Distinct ERP components associated with reward cues, task-preparatory and task-monitoring processes, and reward feedback processes were identified. Unsurprisingly, participants displayed increased ERP amplitudes associated with task-preparatory processes following cues that predicted higher chances of reward. They also rapidly updated reward and loss prediction information dependent on task performance after the first feedback signal. Finally, upon reward receipt, initial reward probability was no longer taken into account. Rather, ERP measures suggested that only the magnitude of actual reward or loss was now processed. Reward and task-monitoring processes are clearly dissociable, but interact across very fast timescales to update reward predictions as information about task success or failure is accrued. Careful delineation of these processes will be useful in future investigations in clinical groups where such processes are suspected of having gone awry. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Reward Contingencies and the Recalibration of Task Monitoring and Reward Systems: A high-density electrical mapping study

PubMed Central

Morie, Kristen P.; De Sanctis, Pierfilippo; Foxe, John J.

2014-01-01

Task execution almost always occurs in the context of reward-seeking or punishment-avoiding behavior. As such, ongoing task monitoring systems are influenced by reward anticipation systems. In turn, when a task has been executed either successfully or unsuccessfully, future iterations of that task will be re-titrated on the basis of the task outcome. Here, we examined the neural underpinnings of the task-monitoring and reward-evaluation systems to better understand how they govern reward seeking behavior. Twenty-three healthy adult participants performed a task where they accrued points that equated to real world value (gift cards) by responding as rapidly as possible within an allotted timeframe, while success rate was titrated online by changing the duration of the timeframe dependent on participant performance. Informative cues initiated each trial, indicating the probability of potential reward or loss (four levels from very low to very high). We manipulated feedback by first informing participants of task success/failure, after which a second feedback signal indicated actual magnitude of reward/loss. High-density EEG recordings allowed for examination of event-related potentials (ERPs) to the informative cues and in turn, to both feedback signals. Distinct ERP components associated with reward cues, task preparatory and task monitoring processes, and reward feedback processes were identified. Unsurprisingly, participants displayed increased ERP amplitudes associated with task preparatory processes following cues that predicted higher chances of reward. They also rapidly updated reward and loss prediction information dependent on task performance after the first feedback signal. Finally, upon reward receipt, initial reward probability was no longer taken into account. Rather, ERP measures suggested that only the magnitude of actual reward or loss was now processed. Reward and task monitoring processes are clearly dissociable, but interact across very fast timescales to update reward predictions as information about task success or failure is accrued. Careful delineation of these processes will be useful in future investigations in clinical groups where such processes are suspected of having gone awry. PMID:24836852

Self-reflection modulates the outcome evaluation process: Evidence from an ERP study.

PubMed

Zhu, Xiangru; Gu, Ruolei; Wu, Haiyan; Luo, Yuejia

2015-12-01

Recent research demonstrated structural overlap between reward and self processing, but the functional relationship that explains how self processing influences reward processing remains unclear. The present study used an experimentally constrained reflection task to investigate whether individuals' outcome evaluations in a gambling task are modulated by task-unrelated self- and other-reflection processes. The self- and other-reflection task contained descriptions of the self or others, and brain event-related potentials (ERPs) were recorded while 16 normal adults performed a gambling task. The ERP analysis focused on the feedback-related negativity (FRN) component. We found that the difference wave of FRN increased in the self-reflection condition compared with the other-reflection condition. The present findings provide direct evidence that self processing can influence reward processing. Copyright © 2015 Elsevier B.V. All rights reserved.

Process Versus Task in Social Planning

ERIC Educational Resources Information Center

Gilbert, Neil; Specht, Harry

1977-01-01

For several decades, the relative importance of process as opposed to task has been an issue in the literature. This study of the Model Cities program examines the relationship between program outcomes and the process and task orientations of program planners. (Author)

Thermal-mechanical fatigue behavior of nickel-base superalloys

NASA Technical Reports Server (NTRS)

Pelloux, R. M.; Marchand, N.

1986-01-01

The main achievements of a 36-month research program are presented. The main objective was to gain more insight into the problem of crack growth under thermal mechanical fatigue (TMF) conditions. This program was conducted at M.I.T. for the period of September 1982 to September 1985. The program was arranged into five technical tasks. Under Task I, the literature of TMF data was reviewed. The goal was to identify the crack propagation conditions in aircraft engines (hot section) and to assess the validity of conventional fracture mechanics parameters to address TMF crack growth. The second task defined the test facilities, test specimen and the testing conditions needed to establish the effectiveness of data correlation parameters identified in Task I. Three materials (Inconel X-750, Hastelloy-X, and B-1900) were chosen for the program. Task II was accomplished in collaboration with Pratt & Whitney Aircraft engineers. Under Task III, a computerized testing system to measure the TMF behavior (LCF and CG behaviors) of various alloys systems was built. The software used to run isothermal and TMF tests was also developed. Built around a conventional servohydraulic machine, the system is capable of push-pull tests under stress or strain and temperature controlled conditions in the temperature range of 25C to 1050C. A crack propagation test program was defined and conducted under Task IV. The test variables included strain range, strain rate (frequency) and temperature. Task V correlated and generalized the Task IV data for isothermal and variable temperature conditions so that several crack propagation parameters could be compared and evaluated. The structural damage (mode of cracking and dislocation substructure) under TMF cycling was identified and contrasted with the isothermal damage to achieve a sound fundamental mechanistic understanding of TMF.

Processing deficits in monitoring analog and digital displays: Implications for attentional theory and mental-state estimation research

NASA Technical Reports Server (NTRS)

Payne, David G.; Gunther, Virginia A. L.

1988-01-01

Subjects performed short term memory tasks, involving both spatial and verbal components, and a visual monitoring task involving either analog or digital display formats. These two tasks (memory vs. monitoring) were performed both singly and in conjunction. Contrary to expectations derived from multiple resource theories of attentional processes, there was no evidence that when the two tasks involved the same cognitive codes (i.e., either both spatial or both verbal/linguistics) there was more of a dual task performance decrement than when the two tasks employed different cognitive codes/processes. These results are discussed in terms of their implications for theories of attentional processes and also for research in mental state estimation.

Discussion of the Special Issue on Growth Models for Longitudinal Data in Educational Research

ERIC Educational Resources Information Center

Molenaar, Peter C. M.; Campbell, Cynthia G.

2008-01-01

In his introduction to this special issue, Roger Millsap has given an excellent summary of its contents. This eases our task considerably. In what follows, we first present some general observations about growth curve modeling of longitudinal data. Among other things, we will address the criticism that the popular latent growth curve model may…

Alpha power increases in right parietal cortex reflects focused internal attention

PubMed Central

Benedek, Mathias; Schickel, Rainer J.; Jauk, Emanuel; Fink, Andreas; Neubauer, Aljoscha C.

2014-01-01

This study investigated the functional significance of EEG alpha power increases, a finding that is consistently observed in various memory tasks and specifically during divergent thinking. It was previously shown that alpha power is increased when tasks are performed in mind—e.g., when bottom-up processing is prevented. This study aimed to examine the effect of task-immanent differences in bottom-up processing demands by comparing two divergent thinking tasks, one intrinsically relying on bottom-up processing (sensory-intake task) and one that is not (sensory-independence task). In both tasks, stimuli were masked in half of the trials to establish conditions of higher and lower internal processing demands. In line with the hypotheses, internal processing affected performance and led to increases in alpha power only in the sensory-intake task, whereas the sensory-independence task showed high levels of task-related alpha power in both conditions. Interestingly, conditions involving focused internal attention showed a clear lateralization with higher alpha power in parietal regions of the right hemisphere. Considering evidence from fMRI studies, right-parietal alpha power increases may correspond to a deactivation of the right temporoparietal junction, reflecting an inhibition of the ventral attention network. Inhibition of this region is thought to prevent reorienting to irrelevant stimulation during goal-driven, top-down behavior, which may serve the executive function of task shielding during demanding cognitive tasks such as idea generation and mental imagery. PMID:24561034

Processing of task-irrelevant emotional faces impacted by implicit sequence learning.

PubMed

Peng, Ming; Cai, Mengfei; Zhou, Renlai

2015-12-02

Attentional load may be increased by task-relevant attention, such as difficulty of task, or task-irrelevant attention, such as an unexpected light-spot in the screen. Several studies have focused on the influence of task-relevant attentional load on task-irrelevant emotion processing. In this study, we used event-related potentials to examine the impact of task-irrelevant attentional load on task-irrelevant expression processing. Eighteen participants identified the color of a word (i.e. the color Stroop task) while a picture of a fearful or a neutral face was shown in the background. The task-irrelevant attentional load was increased by regularly presented congruence trials (congruence between the color and the meaning of the word) in the regular condition because implicit sequence learning was induced. We compared the task-irrelevant expression processing between the regular condition and the random condition (the congruence and incongruence trials were presented randomly). Behaviorally, reaction times for the fearful face condition were faster than the neutral faces condition in the random condition, whereas no significant difference was found in the regular condition. The event-related potential results indicated enhanced positive amplitudes in P2, N2, and P3 components relative to neutral faces in the random condition. In comparison, only P2 differed significantly for the two types of expressions in the regular condition. The study showed that attentional load increased by implicit sequence learning influenced the late processing of task-irrelevant expression.

Information-Processing and Perceptions of Control: How Attribution Style Affects Task-Relevant Processing

ERIC Educational Resources Information Center

Yeigh, Tony

2007-01-01

This study investigated the effects of perceived controllability on information processing within Weiner's (1985, 1986) attributional model of learning. Attributional style was used to identify trait patterns of controllability for 37 university students. Task-relevant feedback on an information-processing task was then manipulated to test for…

The levels of perceptual processing and the neural correlates of increasing subjective visibility.

PubMed

Binder, Marek; Gociewicz, Krzysztof; Windey, Bert; Koculak, Marcin; Finc, Karolina; Nikadon, Jan; Derda, Monika; Cleeremans, Axel

2017-10-01

According to the levels-of-processing hypothesis, transitions from unconscious to conscious perception may depend on stimulus processing level, with more gradual changes for low-level stimuli and more dichotomous changes for high-level stimuli. In an event-related fMRI study we explored this hypothesis using a visual backward masking procedure. Task requirements manipulated level of processing. Participants reported the magnitude of the target digit in the high-level task, its color in the low-level task, and rated subjective visibility of stimuli using the Perceptual Awareness Scale. Intermediate stimulus visibility was reported more frequently in the low-level task, confirming prior behavioral results. Visible targets recruited insulo-fronto-parietal regions in both tasks. Task effects were observed in visual areas, with higher activity in the low-level task across all visibility levels. Thus, the influence of level of processing on conscious perception may be mediated by attentional modulation of activity in regions representing features of consciously experienced stimuli. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of semantic context on prospective memory performance.

PubMed

Thomas, Brandon J; McBride, Dawn M

2016-01-01

The current study provides evidence for spontaneous processing in prospective memory (PM) or memory for intentions. Discrepancy-plus-search is the spontaneous processing of PM cues via disruptions in processing fluency of ongoing task items. We tested whether this mechanism can be demonstrated in an ongoing rating task with a dominant semantic context. Ongoing task items were manipulated such that the PM cues were members of a semantic category (i.e., Body Parts) that was congruent or discrepant with the dominant semantic category in the ongoing task. Results showed that participants correctly responded to more PM cues when there was a category discrepancy between the PM cues and ongoing task items. Moreover, participants' identification of PM cues was accompanied by faster ongoing task reaction times when PM cues were discrepant with ongoing task items than when they were congruent. These results suggest that a discrepancy-plus-search process supports PM retrieval in certain contexts, and that some discrepancy-plus-search mechanisms may result from the violation of processing expectations within a semantic context.

Nucleation and crystal growth behavior of nepheline in simulated high-level waste glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K.; Amoroso, J.; Mcclane, D.

The Savannah River National Laboratory (SRNL) has been tasked with supporting glass formulation development and process control strategies in key technical areas, relevant to the Department of Energy’s Office of River Protection (DOE-ORP) and related to high-level waste (HLW) vitrification at the Waste Treatment and Immobilization Plant (WTP). Of specific interest is the development of predictive models for crystallization of nepheline (NaAlSiO4) in HLW glasses formulated at high alumina concentrations. This report summarizes recent progress by researchers at SRNL towards developing a predicative tool for quantifying nepheline crystallization in HLW glass canisters using laboratory experiments. In this work, differential scanningmore » calorimetry (DSC) was used to obtain the temperature regions over which nucleation and growth of nepheline occur in three simulated HLW glasses - two glasses representative of WTP projections and one glass representative of the Defense Waste Processing Facility (DWPF) product. The DWPF glass, which has been studied previously, was chosen as a reference composition and for comparison purposes. Complementary quantitative X-ray diffraction (XRD) and optical microscopy confirmed the validity of the methodology to determine nucleation and growth behavior as a function of temperature. The nepheline crystallization growth region was determined to generally extend from ~ 500 to >850 °C, with the maximum growth rates occurring between 600 and 700 °C. For select WTP glass compositions (high Al2O3 and B2O3), the nucleation range extended from ~ 450 to 600 °C, with the maximum nucleation rates occurring at ~ 530 °C. For the DWPF glass composition, the nucleation range extended from ~ 450 to 750 °C with the maximum nucleation rate occurring at ~ 640 °C. The nepheline growth at the peak temperature, as determined by XRD, was between 35 - 75 wt.% /hour. A maximum nepheline growth rate of ~ 0.1 mm/hour at 700 °C was measured for the DWPF composition using optical microscopy. This research establishes a viable alternative to more traditional techniques for evaluating nepheline crystallization in large numbers of glasses, which are prohibitively time consuming or otherwise impractical. The ultimate objective is to combine the nucleation and growth information obtained from DSC, like that presented in this report, with computer simulations of glass cooling within the canister to accurately predict nepheline crystallization in HLW during processing through WTP.« less

The relation between Assessment for Learning and elementary students' cognitive and metacognitive strategy use.

PubMed

Baas, Diana; Castelijns, Jos; Vermeulen, Marjan; Martens, Rob; Segers, Mien

2015-03-01

Assessment for Learning (AfL) is believed to create a rich learning environment in which students develop their cognitive and metacognitive strategies. Monitoring student growth and providing scaffolds that shed light on the next step in the learning process are hypothesized to be essential elements of AfL that enhance cognitive and metacognitive strategies. However, empirical evidence for the relation between AfL and students' strategy use is scarce. This study investigates the relation between AfL and elementary school students' use of cognitive and metacognitive strategies. The sample comprised 528 grade four to six students (9- to 12-year-olds) from seven Dutch elementary schools. Students' perceptions of AfL and their cognitive and metacognitive strategy use were measured by means of questionnaires. Structural equation modelling was used to investigate the relations among the variables. The results reveal that monitoring activities that provide students an understanding of where they are in their learning process predict Students' task orientation and planning. Scaffolding activities that support students in taking the next step in their learning are positively related to the use of both surface and deep-level learning strategies and the extent to which they evaluate their learning process after performing tasks. The results underline the importance of assessment practices in ceding responsibility to students in taking control of their own learning. © 2014 The British Psychological Society.

Encoding processes during retrieval tasks.

PubMed

Buckner, R L; Wheeler, M E; Sheridan, M A

2001-04-01

Episodic memory encoding is pervasive across many kinds of task and often arises as a secondary processing effect in tasks that do not require intentional memorization. To illustrate the pervasive nature of information processing that leads to episodic encoding, a form of incidental encoding was explored based on the "Testing" phenomenon: The incidental-encoding task was an episodic memory retrieval task. Behavioral data showed that performing a memory retrieval task was as effective as intentional instructions at promoting episodic encoding. During fMRI imaging, subjects viewed old and new words and indicated whether they remembered them. Relevant to encoding, the fate of the new words was examined using a second, surprise test of recognition after the imaging session. fMRI analysis of those new words that were later remembered revealed greater activity in left frontal regions than those that were later forgotten - the same pattern of results as previously observed for traditional incidental and intentional episodic encoding tasks. This finding may offer a partial explanation for why repeated testing improves memory performance. Furthermore, the observation of correlates of episodic memory encoding during retrieval tasks challenges some interpretations that arise from direct comparisons between "encoding tasks" and "retrieval tasks" in imaging data. Encoding processes and their neural correlates may arise in many tasks, even those nominally labeled as retrieval tasks by the experimenter.

Self-regulated learning processes of medical students during an academic learning task.

PubMed

Gandomkar, Roghayeh; Mirzazadeh, Azim; Jalili, Mohammad; Yazdani, Kamran; Fata, Ladan; Sandars, John

2016-10-01

This study was designed to identify the self-regulated learning (SRL) processes of medical students during a biomedical science learning task and to examine the associations of the SRL processes with previous performance in biomedical science examinations and subsequent performance on a learning task. A sample of 76 Year 1 medical students were recruited based on their performance in biomedical science examinations and stratified into previous high and low performers. Participants were asked to complete a biomedical science learning task. Participants' SRL processes were assessed before (self-efficacy, goal setting and strategic planning), during (metacognitive monitoring) and after (causal attributions and adaptive inferences) their completion of the task using an SRL microanalytic interview. Descriptive statistics were used to analyse the means and frequencies of SRL processes. Univariate and multiple logistic regression analyses were conducted to examine the associations of SRL processes with previous examination performance and the learning task performance. Most participants (from 88.2% to 43.4%) reported task-specific processes for SRL measures. Students who exhibited higher self-efficacy (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.09-1.90) and reported task-specific processes for metacognitive monitoring (OR 6.61, 95% CI 1.68-25.93) and causal attributions (OR 6.75, 95% CI 2.05-22.25) measures were more likely to be high previous performers. Multiple analysis revealed that similar SRL measures were associated with previous performance. The use of task-specific processes for causal attributions (OR 23.00, 95% CI 4.57-115.76) and adaptive inferences (OR 27.00, 95% CI 3.39-214.95) measures were associated with being a high learning task performer. In multiple analysis, only the causal attributions measure was associated with high learning task performance. Self-efficacy, metacognitive monitoring and causal attributions measures were associated positively with previous performance. Causal attributions and adaptive inferences measures were associated positively with learning task performance. These findings may inform remediation interventions in the early years of medical school training. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

The right look for the job: decoding cognitive processes involved in the task from spatial eye-movement patterns.

PubMed

Król, Magdalena Ewa; Król, Michał

2018-02-20

The aim of the study was not only to demonstrate whether eye-movement-based task decoding was possible but also to investigate whether eye-movement patterns can be used to identify cognitive processes behind the tasks. We compared eye-movement patterns elicited under different task conditions, with tasks differing systematically with regard to the types of cognitive processes involved in solving them. We used four tasks, differing along two dimensions: spatial (global vs. local) processing (Navon, Cognit Psychol, 9(3):353-383 1977) and semantic (deep vs. shallow) processing (Craik and Lockhart, J Verbal Learn Verbal Behav, 11(6):671-684 1972). We used eye-movement patterns obtained from two time periods: fixation cross preceding the target stimulus and the target stimulus. We found significant effects of both spatial and semantic processing, but in case of the latter, the effect might be an artefact of insufficient task control. We found above chance task classification accuracy for both time periods: 51.4% for the period of stimulus presentation and 34.8% for the period of fixation cross presentation. Therefore, we show that task can be to some extent decoded from the preparatory eye-movements before the stimulus is displayed. This suggests that anticipatory eye-movements reflect the visual scanning strategy employed for the task at hand. Finally, this study also demonstrates that decoding is possible even from very scant eye-movement data similar to Coco and Keller, J Vis 14(3):11-11 (2014). This means that task decoding is not limited to tasks that naturally take longer to perform and yield multi-second eye-movement recordings.

Mechanisms of Practice-Related Reductions of Dual-Task Interference with Simple Tasks: Data and Theory

PubMed Central

Strobach, Tilo; Torsten, Schubert

2017-01-01

In dual-task situations, interference between two simultaneous tasks impairs performance. With practice, however, this impairment can be reduced. To identify mechanisms leading to a practice-related improvement in sensorimotor dual tasks, the present review applied the following general hypothesis: Sources that impair dual-task performance at the beginning of practice are associated with mechanisms for the reduction of dual-task impairment at the end of practice. The following types of processes provide sources for the occurrence of this impairment: (a) capacity-limited processes within the component tasks, such as response-selection or motor response stages, and (b) cognitive control processes independent of these tasks and thus operating outside of component-task performance. Dual-task practice studies show that, under very specific conditions, capacity-limited processes within the component tasks are automatized with practice, reducing the interference between two simultaneous tasks. Further, there is evidence that response-selection stages are shortened with practice. Thus, capacity limitations at these stages are sources for dual-task costs at the beginning of practice and are overcome with practice. However, there is no evidence demonstrating the existence of practice-related mechanisms associated with capacity-limited motor-response stages. Further, during practice, there is an acquisition of executive control skills for an improved allocation of limited attention resources to two tasks as well as some evidence supporting the assumption of improved task coordination. These latter mechanisms are associated with sources of dual-task interference operating outside of component task performance at the beginning of practice and also contribute to the reduction of dual-task interference at its end. PMID:28439319

Motor demands impact speed of information processing in Autism Spectrum Disorders

PubMed Central

Kenworthy, Lauren; Yerys, Benjamin E.; Weinblatt, Rachel; Abrams, Danielle N.; Wallace, Gregory L.

2015-01-01

Objective The apparent contradiction between preserved or even enhanced perceptual processing speed on inspection time tasks in autism spectrum disorders (ASD) and impaired performance on complex processing speed tasks that require motor output (e.g. Wechsler Processing Speed Index) has not yet been systematically investigated. This study investigates whether adding motor output demands to an inspection time task impairs ASD performance compared to that of typically developing control (TDC) children. Method The performance of children with ASD (n=28; mean FSIQ=115) and TDC (n=25; mean FSIQ=122) children was compared on processing speed tasks with increasing motor demand. Correlations were run between ASD task performance and Autism Diagnostic Observation Schedule (ADOS) Communication scores. Results Performance by the ASD and TDC groups on a simple perceptual processing speed task with minimal motor demand was equivalent, though it diverged (ASD worse than TDC) on two tasks with the same stimuli, but increased motor output demands. ASD performance on the moderate but not the high speeded motor output demand task was negatively correlated with ADOS communication symptoms. Conclusions These data address the apparent contradiction between preserved inspection time in the context of slowed “processing speed” in ASD. They show that processing speed is preserved when motor demands are minimized, but that increased motor output demands interfere with the ability to act on perceptual processing of simple stimuli. Reducing motor demands (e.g. through the use of computers) may increase the capacity of people with ASD to demonstrate good perceptual processing in a variety of educational, vocational and social settings. PMID:23937483

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

PubMed

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.

Identifying Learning Patterns of Children at Risk for Specific Reading Disability

PubMed Central

Barbot, Baptiste; Krivulskaya, Suzanna; Hein, Sascha; Reich, Jodi; Thuma, Philip E.; Grigorenko, Elena L.

2016-01-01

Differences in learning patterns of vocabulary acquisition in children at risk (+SRD) and not at risk (SRD) for Specific Reading Disability (SRD) were examined using a microdevelopmental paradigm applied to the multi-trial Foreign Language Learning Task (FLLT; Baddeley et al., 1995). The FLLT was administered to 905 children from rural Chitonga-speaking Zambia. A multi-group Latent Growth Curve Model (LGCM) was implemented to study interindividual differences in intraindividual change across trials. Results showed that the +SRD group recalled fewer words correctly in the first trial, learned at a slower rate during the subsequent trials, and demonstrated a more linear learning pattern compared to the SRD group. This study illustrates the promise of LGCM applied to multi-trial learning tasks, by isolating three components of the learning process (initial recall, rate of learning, and functional pattern of learning). Implications of this microdevelopmental approach to SRD research in low-to-middle income countries are discussed. PMID:26037654

Thermosolutal convection and macrosegregation in dendritic alloys

NASA Technical Reports Server (NTRS)

Poirier, David R.; Heinrich, J. C.

1993-01-01

A mathematical model of solidification, that simulates the formation of channel segregates or freckles, is presented. The model simulates the entire solidification process, starting with the initial melt to the solidified cast, and the resulting segregation is predicted. Emphasis is given to the initial transient, when the dendritic zone begins to develop and the conditions for the possible nucleation of channels are established. The mechanisms that lead to the creation and eventual growth or termination of channels are explained in detail and illustrated by several numerical examples. A finite element model is used for the simulations. It uses a single system of equations to deal with the all-liquid region, the dendritic region, and the all-solid region. The dendritic region is treated as an anisotropic porous medium. The algorithm uses the bilinear isoparametric element, with a penalty function approximation and a Petrov-Galerkin formulation. The major task was to develop the solidification model. In addition, other tasks that were performed in conjunction with the modeling of dendritic solidification are briefly described.

Identifying learning patterns of children at risk for Specific Reading Disability.

PubMed

Barbot, Baptiste; Krivulskaya, Suzanna; Hein, Sascha; Reich, Jodi; Thuma, Philip E; Grigorenko, Elena L

2016-05-01

Differences in learning patterns of vocabulary acquisition in children at risk (+SRD) and not at risk (-SRD) for Specific Reading Disability (SRD) were examined using a microdevelopmental paradigm applied to the multi-trial Foreign Language Learning Task (FLLT; Baddeley et al., 1995). The FLLT was administered to 905 children from rural Chitonga-speaking Zambia. A multi-group Latent Growth Curve Model (LGCM) was implemented to study interindividual differences in intraindividual change across trials. Results showed that the +SRD group recalled fewer words correctly in the first trial, learned at a slower rate during the subsequent trials, and demonstrated a more linear learning pattern compared to the -SRD group. This study illustrates the promise of LGCM applied to multi-trial learning tasks, by isolating three components of the learning process (initial recall, rate of learning, and functional pattern of learning). Implications of this microdevelopmental approach to SRD research in low-to-middle income countries are discussed. © 2015 John Wiley & Sons Ltd.

Explicit attention interferes with selective emotion processing in human extrastriate cortex.

PubMed

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-02-22

Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (approximately 150-300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon.

Explicit attention interferes with selective emotion processing in human extrastriate cortex

PubMed Central

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-01-01

Background Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (~150–300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Results Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. Conclusion The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon. PMID:17316444

Goal neglect, fluid intelligence and processing speed: Manipulating instruction load and inter-stimulus interval.

PubMed

Iveson, Matthew H; Della Sala, Sergio; Anderson, Mike; MacPherson, Sarah E

2017-05-01

Goal maintenance is the process where task rules and instructions are kept active to exert their control on behavior. When this process fails, an individual may ignore a rule while performing the task, despite being able to describe it after task completion. Previous research has suggested that the goal maintenance system is limited by the number of concurrent rules which can be maintained during a task, and that this limit is dependent on an individual's level of fluid intelligence. However, the speed at which an individual can process information may also limit their ability to use task rules when the task demands them. In the present study, four experiments manipulated the number of instructions to be maintained by younger and older adults and examined whether performance on a rapid letter-monitoring task was predicted by individual differences in fluid intelligence or processing speed. Fluid intelligence played little role in determining how frequently rules were ignored during the task, regardless of the number of rules to be maintained. In contrast, processing speed predicted the rate of goal neglect in older adults, where increasing the presentation rate of the letter-monitoring task increased goal neglect. These findings suggest that goal maintenance may be limited by the speed at which it can operate. Copyright © 2017. Published by Elsevier B.V.

Embodied simulation as part of affective evaluation processes: task dependence of valence concordant EMG activity.

PubMed

Weinreich, André; Funcke, Jakob Maria

2014-01-01

Drawing on recent findings, this study examines whether valence concordant electromyography (EMG) responses can be explained as an unconditional effect of mere stimulus processing or as somatosensory simulation driven by task-dependent processing strategies. While facial EMG over the Corrugator supercilii and the Zygomaticus major was measured, each participant performed two tasks with pictures of album covers. One task was an affective evaluation task and the other was to attribute the album covers to one of five decades. The Embodied Emotion Account predicts that valence concordant EMG is more likely to occur if the task necessitates a somatosensory simulation of the evaluative meaning of stimuli. Results support this prediction with regard to Corrugator supercilii in that valence concordant EMG activity was only present in the affective evaluation task but not in the non-evaluative task. Results for the Zygomaticus major were ambiguous. Our findings are in line with the view that EMG activity is an embodied part of the evaluation process and not a mere physical outcome.

Effects of Divided Attention at Retrieval on Conceptual Implicit Memory

PubMed Central

Prull, Matthew W.; Lawless, Courtney; Marshall, Helen M.; Sherman, Annabella T. K.

2016-01-01

This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes. PMID:26834678

Effects of Divided Attention at Retrieval on Conceptual Implicit Memory.

PubMed

Prull, Matthew W; Lawless, Courtney; Marshall, Helen M; Sherman, Annabella T K

2016-01-01

This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes.

Dynamics of Cooperation in a Task Completion Social Dilemma

PubMed Central

Passino, Kevin M.

2017-01-01

We study the situation where the members of a community have the choice to participate in the completion of a common task. The process of completing the task involves only costs and no benefits to the individuals that participate in this process. However, completing the task results in changes that significantly benefit the community and that exceed the participation efforts. A task completion social dilemma arises when the short-term participation costs dissipate any interest in the community members to contribute to the task completion process and therefore to obtain the benefits that result from completing the task. In this work, we model the task completion problem using a dynamical system that characterizes the participation dynamics in the community and the task completion process. We show how this model naturally allows for the incorporation of several mechanisms that facilitate the emergence of cooperation and that have been studied in previous research on social dilemmas, including communication across a network, and indirect reciprocity through relative reputation. We provide mathematical analyses and computer simulations to study the qualitative properties of the participation dynamics in the community for different scenarios. PMID:28125721

Tree demography dominates long-term growth trends inferred from tree rings.

PubMed

Brienen, Roel J W; Gloor, Manuel; Ziv, Guy

2017-02-01

Understanding responses of forests to increasing CO 2 and temperature is an important challenge, but no easy task. Tree rings are increasingly used to study such responses. In a recent study, van der Sleen et al. (2014) Nature Geoscience, 8, 4 used tree rings from 12 tropical tree species and find that despite increases in intrinsic water use efficiency, no growth stimulation is observed. This challenges the idea that increasing CO 2 would stimulate growth. Unfortunately, tree ring analysis can be plagued by biases, resulting in spurious growth trends. While their study evaluated several biases, it does not account for all. In particular, one bias may have seriously affected their results. Several of the species have recruitment patterns, which are not uniform, but clustered around one specific year. This results in spurious negative growth trends if growth rates are calculated in fixed size classes, as 'fast-growing' trees reach the sampling diameter earlier compared to slow growers and thus fast growth rates tend to have earlier calendar dates. We assessed the effect of this 'nonuniform age bias' on observed growth trends and find that van der Sleen's conclusions of a lack of growth stimulation do not hold. Growth trends are - at least partially - driven by underlying recruitment or age distributions. Species with more clustered age distributions show more negative growth trends, and simulations to estimate the effect of species' age distributions show growth trends close to those observed. Re-evaluation of the growth data and correction for the bias result in significant positive growth trends of 1-2% per decade for the full period, and 3-7% since 1950. These observations, however, should be taken cautiously as multiple biases affect these trend estimates. In all, our results highlight that tree ring studies of long-term growth trends can be strongly influenced by biases if demographic processes are not carefully accounted for. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

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

ERIC Educational Resources Information Center

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

2009-01-01

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

Growth Trajectories of Task Value and Self-Efficacy across an Academic Semester

ERIC Educational Resources Information Center

Johnson, Marcus Lee; Edwards, Ordene V.; Dai, Ting

2014-01-01

Many scholars have argued that motivation is dynamic and malleable across time and contexts. In this article, we investigated changes in undergraduates' task value and self-efficacy across an academic semester. Sixty three undergraduate students completed the Motivated Strategies for Learning Questionnaire across five time points in their…

Lexical Development in Mandarin-English Bilingual Children

ERIC Educational Resources Information Center

Sheng, Li; Lu, Ying; Kan, Pui Fong

2011-01-01

Two groups of Mandarin-English bilingual children (3-5-year-olds, 6-8-year-olds) participated in a picture identification task and a picture naming task in both languages. Results revealed age-related growth in English, but not Mandarin vocabulary. Composite vocabulary was larger than either single-language vocabulary in the younger children but…

Social Justice and Proportional Reasoning

ERIC Educational Resources Information Center

Simic-Muller, Ksenija

2015-01-01

Ratio and proportional reasoning tasks abound that have connections to real-world situations. Examples in this article demonstrate how textbook tasks can easily be transformed into authentic real-world problems that shed light on issues of equity and fairness, such as population growth and crime rates. A few ideas are presented on how teachers can…

Preferential processing of task-irrelevant beloved-related information and task performance: Two event-related potential studies.

PubMed

Langeslag, Sandra J E; van Strien, Jan W

2017-09-18

People who are in love have better attention for beloved-related information, but report having trouble focusing on other tasks, such as (home)work. So, romantic love can both improve and hurt cognition. Emotional information is preferentially processed, which improves task performance when the information is task-relevant, but hurts task performance when it is task-irrelevant. Because beloved-related information is highly emotional, the effects of romantic love on cognition may resemble these effects of emotion on cognition. We examined whether beloved-related information is preferentially processed even when it is task-irrelevant and whether this hurts task performance. In two event-related potential studies, participants who had recently fallen in love performed a visuospatial short-term memory task. Task-irrelevant beloved, friend, and stranger faces were presented during maintenance (Study 1), or encoding (Study 2). The Early Posterior Negativity (EPN) reflecting early automatic attentional capturing and the Late Positive Potential (LPP) reflecting sustained motivated attention were largest for beloved pictures. Thus, beloved pictures are preferentially processed even when they are task-irrelevant. Task performance and reaction times did not differ between beloved, friend, and stranger conditions. Nevertheless, self-reported obsessive thinking about the beloved tended to correlate negatively with task performance, and positively with reaction times, across conditions. So, although task-irrelevant beloved-related information does not impact task performance, more obsessive thinking about the beloved might relate to poorer and slower overall task performance. More research is needed to clarify why people experience trouble focusing on beloved-unrelated tasks and how this negative effect of love on cognition could be reduced. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of cue-task association and location on switch cost and alternating-switch cost.

PubMed

Arbuthnott, Katherine D; Woodward, Todd S

2002-03-01

Task-switching performance is strongly influenced by whether the imperative stimulus uniquely specifies which task to perform: Switch cost is substantial with bivalent stimuli but is greatly reduced with univalent stimuli, suggesting that available contextual information influences processing in task-switching situations. The present study examined whether task-relevant information provided by task cues influences the magnitude of switch cost in a parallel manner. Cues presented 500 ms prior to a trivalent stimulus indicated which of three tasks to perform. These cues either had a preexisting association with the to-be-performed task (verbal cues), or a recently learned association with the task (spatial and shape cues). The results paralleled the effects of stimulus bivalence: substantial switch cost with recently learned cue-task associations and greatly reduced switch cost with preexisting cue-task associations. This suggests that both stimulus-based and cue-based information can activate the relevant task set, possibly providing external support to endogenous control processes. Alternating-switch cost, a greater cost for switching back to a recently abandoned task, was also observed with both preexisting and recently learned cue-task associations, but only when all tasks were presented in a consistent spatial location. When spatial location was used to cue the to-be-performed tasks, no alternating-switch cost was observed, suggesting that different processes may be involved when tasks are uniquely located in space. Specification of the nature of these processes may prove to be complex, as post-hoc inspection of the data suggested that for the spatial cue condition, the alternating-switch cost may oscillate between cost and benefit, depending on the relevant task.

Erroneous knowledge of results affects decision and memory processes on timing tasks.

PubMed

Ryan, Lawrence J; Fritz, Matthew S

2007-12-01

On mental timing tasks, erroneous knowledge of results (KR) leads to incorrect performance accompanied by the subjective judgment of accurate performance. Using the start-stop technique (an analogue of the peak interval procedure) with both reproduction and production timing tasks, the authors analyze what processes erroneous KR alters. KR provides guidance (performance error information) that lowers decision thresholds. Erroneous KR also provides targeting information that alters response durations proportionately to the magnitude of the feedback error. On the production task, this shift results from changes in the reference memory, whereas on the reproduction task this shift results from changes in the decision threshold for responding. The idea that erroneous KR can alter different cognitive processes on related tasks is supported by the authors' demonstration that the learned strategies can transfer from the reproduction task to the production task but not visa versa. Thus effects of KR are both task and context dependent.

Dual-Task Processing When Task 1 Is Hard and Task 2 Is Easy: Reversed Central Processing Order?

ERIC Educational Resources Information Center

Leonhard, Tanja; Fernandez, Susana Ruiz; Ulrich, Rolf; Miller, Jeff

2011-01-01

Five psychological refractory period (PRP) experiments were conducted with an especially time-consuming first task (Experiments 1, 3, and 5: mental rotation; Experiments 2 and 4: memory scanning) and with equal emphasis on the first task and on the second (left-right tone judgment). The standard design with varying stimulus onset asynchronies…

Context transfer in reinforcement learning using action-value functions.

PubMed

Mousavi, Amin; Nadjar Araabi, Babak; Nili Ahmadabadi, Majid

2014-01-01

This paper discusses the notion of context transfer in reinforcement learning tasks. Context transfer, as defined in this paper, implies knowledge transfer between source and target tasks that share the same environment dynamics and reward function but have different states or action spaces. In other words, the agents learn the same task while using different sensors and actuators. This requires the existence of an underlying common Markov decision process (MDP) to which all the agents' MDPs can be mapped. This is formulated in terms of the notion of MDP homomorphism. The learning framework is Q-learning. To transfer the knowledge between these tasks, the feature space is used as a translator and is expressed as a partial mapping between the state-action spaces of different tasks. The Q-values learned during the learning process of the source tasks are mapped to the sets of Q-values for the target task. These transferred Q-values are merged together and used to initialize the learning process of the target task. An interval-based approach is used to represent and merge the knowledge of the source tasks. Empirical results show that the transferred initialization can be beneficial to the learning process of the target task.

Context Transfer in Reinforcement Learning Using Action-Value Functions

PubMed Central

Mousavi, Amin; Nadjar Araabi, Babak; Nili Ahmadabadi, Majid

2014-01-01

This paper discusses the notion of context transfer in reinforcement learning tasks. Context transfer, as defined in this paper, implies knowledge transfer between source and target tasks that share the same environment dynamics and reward function but have different states or action spaces. In other words, the agents learn the same task while using different sensors and actuators. This requires the existence of an underlying common Markov decision process (MDP) to which all the agents' MDPs can be mapped. This is formulated in terms of the notion of MDP homomorphism. The learning framework is Q-learning. To transfer the knowledge between these tasks, the feature space is used as a translator and is expressed as a partial mapping between the state-action spaces of different tasks. The Q-values learned during the learning process of the source tasks are mapped to the sets of Q-values for the target task. These transferred Q-values are merged together and used to initialize the learning process of the target task. An interval-based approach is used to represent and merge the knowledge of the source tasks. Empirical results show that the transferred initialization can be beneficial to the learning process of the target task. PMID:25610457

Is Semantic Processing During Sentence Reading Autonomous or Controlled? Evidence from the N400 Component in a Dual Task Paradigm

PubMed Central

Hohlfeld, Annette; Martín-Loeches, Manuel; Sommer, Werner

2015-01-01

The present study contributes to the discussion on the automaticity of semantic processing. Whereas most previous research investigated semantic processing at word level, the present study addressed semantic processing during sentence reading. A dual task paradigm was combined with the recording of event-related brain potentials. Previous research at word level processing reported different patterns of interference with the N400 by additional tasks: attenuation of amplitude or delay of latency. In the present study, we presented Spanish sentences that were semantically correct or contained a semantic violation in a critical word. At different intervals preceding the critical word a tone was presented that required a high-priority choice response. At short intervals/high temporal overlap between the tasks mean amplitude of the N400 was reduced relative to long intervals/low temporal overlap, but there were no shifts of peak latency. We propose that processing at sentence level exerts a protective effect against the additional task. This is in accord with the attentional sensitization model (Kiefer & Martens, 2010), which suggests that semantic processing is an automatic process that can be enhanced by the currently activated task set. The present experimental sentences also induced a P600, which is taken as an index of integrative processing. Additional task effects are comparable to those in the N400 time window and are briefly discussed. PMID:26203312

Professional or administrative value patterns? Clinical pathways in medical problem-solving processes.

PubMed

Holmberg, Leif

2007-11-01

A health-care organization simultaneously belongs to two different institutional value patterns: a professional and an administrative value pattern. At the administrative level, medical problem-solving processes are generally perceived as the efficient application of familiar chains of activities to well-defined problems; and a low task uncertainty is therefore assumed at the work-floor level. This assumption is further reinforced through clinical pathways and other administrative guidelines. However, studies have shown that in clinical practice such administrative guidelines are often considered inadequate and difficult to implement mainly because physicians generally perceive task uncertainty to be high and that the guidelines do not cover the scope of encountered deviations. The current administrative level guidelines impose uniform structural features that meet the requirement for low task uncertainty. Within these structural constraints, physicians must organize medical problem-solving processes to meet any task uncertainty that may be encountered. Medical problem-solving processes with low task uncertainty need to be organized independently of processes with high task uncertainty. Each process must be evaluated according to different performance standards and needs to have autonomous administrative guideline models. Although clinical pathways seem appropriate when there is low task uncertainty, other kinds of guidelines are required when the task uncertainty is high.

Final Report: Vapor Transport Deposition for Thin Film III-V Photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boettcher, Shannon; Greenaway, Ann; Boucher, Jason

2016-02-10

Silicon, the dominant photovoltaic (PV) technology, is reaching its fundamental performance limits as a single absorber/junction technology. Higher efficiency devices are needed to reduce cost further because the balance of systems account for about two-thirds of the overall cost of the solar electricity. III-V semiconductors such as GaAs are used to make the highest-efficiency photovoltaic devices, but the costs of manufacture are much too high for non-concentrated terrestrial applications. The cost of III-V’s is driven by two factors: (1) metal-organic chemical vapor deposition (MOCVD), the dominant growth technology, employs expensive, toxic and pyrophoric gas-phase precursors, and (2) the growth substratesmore » conventionally required for high-performance devices are monocrystalline III-V wafers. The primary goal of this project was to show that close-spaced vapor transport (CSVT), using water vapor as a transport agent, is a scalable deposition technology for growing low-cost epitaxial III-V photovoltaic devices. The secondary goal was to integrate those devices on Si substrates for high-efficiency tandem applications using interface nanopatterning to address the lattice mismatch. In the first task, we developed a CSVT process that used only safe solid-source powder precursors to grow epitaxial GaAs with controlled n and p doping and mobilities/lifetimes similar to that obtainable via MOCVD. Using photoelectrochemical characterization, we showed that the best material had near unity internal quantum efficiency for carrier collection and minority carrier diffusions lengths in of ~ 8 μm, suitable for PV devices with >25% efficiency. In the second task we developed the first pn junction photovoltaics using CSVT and showed unpassivated structures with open circuit photovoltages > 915 mV and internal quantum efficiencies >0.9. We also characterized morphological and electrical defects and identified routes to reduce those defects. In task three we grew epitaxial ternary GaAsxP 1-x and In 0.5Ga 0.5P alloys, with composition set by the ratio of GaAs/GaP or InP/GaP mixed as the source powder. GaAs 0.3P 0.7 has the appropriate bandgap to serve as a top cell on Si and In 0.5Ga 0.5P is near the composition used as a surface passivation layer on GaAs pn junction photovoltaics. In the final task we demonstrated III-V selective area epitaxy using CSVT as a first step toward the growth of III-V micro- or nanostructures for an integrated tandem solar cell on Si. We also found that direct epitaxial growth on Si appears to be impossible in the current H 2O-CSVT reactor design, likely due to the formation of SiO x. This work sets the stage for targeted development of an improved CSVT process and for the scale up of the proof-of-concept work from a research to manufacturing-relevant platform. Replacing H 2O as a transport agent with HCl would provide the ability to deposit directly on Si by avoiding oxide formation and to allow for the deposition of Al-containing alloys that would otherwise oxidize. Improved engineering design and implementation of an in-line multi-station CSVT would allow for direct deposition of device structures in a single system.« less

Predicting dual-task performance with the Multiple Resources Questionnaire (MRQ).

PubMed

Boles, David B; Bursk, Jonathan H; Phillips, Jeffrey B; Perdelwitz, Jason R

2007-02-01

The objective was to assess the validity of the Multiple Resources Questionnaire (MRQ) in predicting dual-task interference. Subjective workload measures such as the Subjective Workload Assessment Technique (SWAT) and NASA Task Load Index are sensitive to single-task parameters and dual-task loads but have not attempted to measure workload in particular mental processes. An alternative is the MRQ. In Experiment 1, participants completed simple laboratory tasks and the MRQ after each. Interference between tasks was then correlated to three different task similarity metrics: profile similarity, based on r(2) between ratings; overlap similarity, based on summed minima; and overall demand, based on summed ratings. Experiment 2 used similar methods but more complex computer-based games. In Experiment 1 the MRQ moderately predicted interference (r = +.37), with no significant difference between metrics. In Experiment 2 the metric effect was significant, with overlap similarity excelling in predicting interference (r = +.83). Mean ratings showed high diagnosticity in identifying specific mental processing bottlenecks. The MRQ shows considerable promise as a cognitive-process-sensitive workload measure. Potential applications of the MRQ include the identification of dual-processing bottlenecks as well as process overloads in single tasks, preparatory to redesign in areas such as air traffic management, advanced flight displays, and medical imaging.

Auditory working memory load impairs visual ventral stream processing: toward a unified model of attentional load.

PubMed

Klemen, Jane; Büchel, Christian; Bühler, Mira; Menz, Mareike M; Rose, Michael

2010-03-01

Attentional interference between tasks performed in parallel is known to have strong and often undesired effects. As yet, however, the mechanisms by which interference operates remain elusive. A better knowledge of these processes may facilitate our understanding of the effects of attention on human performance and the debilitating consequences that disruptions to attention can have. According to the load theory of cognitive control, processing of task-irrelevant stimuli is increased by attending in parallel to a relevant task with high cognitive demands. This is due to the relevant task engaging cognitive control resources that are, hence, unavailable to inhibit the processing of task-irrelevant stimuli. However, it has also been demonstrated that a variety of types of load (perceptual and emotional) can result in a reduction of the processing of task-irrelevant stimuli, suggesting a uniform effect of increased load irrespective of the type of load. In the present study, we concurrently presented a relevant auditory matching task [n-back working memory (WM)] of low or high cognitive load (1-back or 2-back WM) and task-irrelevant images at one of three object visibility levels (0%, 50%, or 100%). fMRI activation during the processing of the task-irrelevant visual stimuli was measured in the lateral occipital cortex and found to be reduced under high, compared to low, WM load. In combination with previous findings, this result is suggestive of a more generalized load theory, whereby cognitive load, as well as other types of load (e.g., perceptual), can result in a reduction of the processing of task-irrelevant stimuli, in line with a uniform effect of increased load irrespective of the type of load.

Holistic processing, contact, and the other-race effect in face recognition.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-12-01

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Maternal Expansions of Child Language Relate to Growth in Children's Vocabulary

ERIC Educational Resources Information Center

Taumoepeau, Mele

2016-01-01

Using multi-level growth modeling, we examined the effect of several measures of maternal input on growth in children's word types from 15-54 months. Mothers and children engaged in a picture description task (N = 77) at 15, 24, 33, and 54 months; the frequency of children's observed word types at each wave was coded and additional independent…

Objects and events as determinants of parallel processing in dual tasks: evidence from the backward compatibility effect.

PubMed

Ellenbogen, Ravid; Meiran, Nachshon

2011-02-01

The backward-compatibility effect (BCE) is a major index of parallel processing in dual tasks and is related to the dependency of Task 1 performance on Task 2 response codes (Hommel, 1998). The results of four dual-task experiments showed that a BCE occurs when the stimuli of both tasks are included in the same visual object (Experiments 1 and 2) or belong to the same perceptual event (Experiments 3 and 4). Thus, the BCE may be modulated by factors that influence whether both task stimuli are included in the same perceptual event (objects, as studied in cognitive experiments, being special cases of events). As with objects, drawing attention to a (selected) event results in the processing of its irrelevant features and may interfere with task execution. (c) 2010 APA, all rights reserved.

Is Adaptation to Task Complexity Really Beneficial for Performance?

ERIC Educational Resources Information Center

Pieschl, Stephanie; Stahl, Elmar; Murray, Tom; Bromme, Rainer

2012-01-01

Theories of self-regulated learning assume that learners flexibly adapt their learning process to external task demands and that this is positively related to performance. In this study, university students (n = 119) solved three tasks that greatly differed in complexity. Their learning processes were captured in detail by task-specific…

Education for Economic Growth: A Critical Investment.

ERIC Educational Resources Information Center

Hunt, James B., Jr.

1984-01-01

Declaring that a "national emergency" exists in American education, the author outlines "Action for Excellence" recommendations developed by the Task Force on Education for Economic Growth, of which he was chairman, and discusses accomplishments in educational reform in the state of North Carolina, where he is governor. (JBM)

Movement Interferes with Visuospatial Working Memory during the Encoding: An ERP Study

PubMed Central

Gunduz Can, Rumeysa; Schack, Thomas; Koester, Dirk

2017-01-01

The present study focuses on the functional interactions of cognition and manual action control. Particularly, we investigated the neurophysiological correlates of the dual-task costs of a manual-motor task (requiring grasping an object, holding it, and subsequently placing it on a target) for working memory (WM) domains (verbal and visuospatial) and processes (encoding and retrieval). Thirty participants were tested in a cognitive-motor dual-task paradigm, in which a single block (a verbal or visuospatial WM task) was compared with a dual block (concurrent performance of a WM task and a motor task). Event-related potentials (ERPs) were analyzed separately for the encoding and retrieval processes of verbal and visuospatial WM domains both in single and dual blocks. The behavioral analyses show that the motor task interfered with WM and decreased the memory performance. The performance decrease was larger for the visuospatial task compared with the verbal task, i.e., domain-specific memory costs were obtained. The ERP analyses show the domain-specific interference also at the neurophysiological level, which is further process-specific to encoding. That is, comparing the patterns of WM-related ERPs in the single block and dual block, we showed that visuospatial ERPs changed only for the encoding process when a motor task was performed at the same time. Generally, the present study provides evidence for domain- and process-specific interactions of a prepared manual-motor movement with WM (visuospatial domain during the encoding process). This study, therefore, provides an initial neurophysiological characterization of functional interactions of WM and manual actions in a cognitive-motor dual-task setting, and contributes to a better understanding of the neuro-cognitive mechanisms of motor action control. PMID:28611714

Cognitive processes in children's reading and attention: the role of working memory, divided attention, and response inhibition.

PubMed

Savage, Robert; Cornish, Kim; Manly, Tom; Hollis, Chris

2006-08-01

Children experiencing attention difficulties have documented cognitive deficits in working memory (WM), response inhibition and dual tasks. Recent evidence suggests however that these same cognitive processes are also closely associated with reading acquisition. This paper therefore explores whether these variables predicted attention difficulties or reading among 123 children with and without significant attention problems sampled from the school population. Children were screened using current WM and attention task measures. Three factors explained variance in WM and attention tasks. Response inhibition tasks loaded mainly with central executive measures, but a dual processing task loaded with the visual-spatial WM measures. Phonological loop measures loaded independently of attention measures. After controls for age, IQ and attention-group membership, phonological loop and 'central processing' measures both predicted reading ability. A 'visual memory/dual-task' factor predicted attention group membership after controls for age, IQ and reading ability. Results thus suggest that some of the processes previously assumed to be predictive of attention problems may reflect processes involved in reading acquisition. Visual memory and dual-task functioning are, however, purer indices of cognitive difficulty in children experiencing attention problems.

Performance monitoring and response conflict resolution associated with choice stepping reaction tasks.

PubMed

Watanabe, Tatsunori; Tsutou, Kotaro; Saito, Kotaro; Ishida, Kazuto; Tanabe, Shigeo; Nojima, Ippei

2016-11-01

Choice reaction requires response conflict resolution, and the resolution processes that occur during a choice stepping reaction task undertaken in a standing position, which requires maintenance of balance, may be different to those processes occurring during a choice reaction task performed in a seated position. The study purpose was to investigate the resolution processes during a choice stepping reaction task at the cortical level using electroencephalography and compare the results with a control task involving ankle dorsiflexion responses. Twelve young adults either stepped forward or dorsiflexed the ankle in response to a visual imperative stimulus presented on a computer screen. We used the Simon task and examined the error-related negativity (ERN) that follows an incorrect response and the correct-response negativity (CRN) that follows a correct response. Error was defined as an incorrect initial weight transfer for the stepping task and as an incorrect initial tibialis anterior activation for the control task. Results revealed that ERN and CRN amplitudes were similar in size for the stepping task, whereas the amplitude of ERN was larger than that of CRN for the control task. The ERN amplitude was also larger in the stepping task than the control task. These observations suggest that a choice stepping reaction task involves a strategy emphasizing post-response conflict and general performance monitoring of actual and required responses and also requires greater cognitive load than a choice dorsiflexion reaction. The response conflict resolution processes appear to be different for stepping tasks and reaction tasks performed in a seated position.

Task-Set Reconfiguration and Perceptual Processing: Behavioral and Electrophysiological Evidence

ERIC Educational Resources Information Center

Mackenzie, Ian G.; Leuthold, Hartmut

2011-01-01

Oriet and Jolicoeur (2003) proposed that an endogenous task-set reconfiguration process acts as a hard bottleneck during which even early perceptual processing is impossible. We examined this assumption using a psychophysiological approach. Participants were required to switch between magnitude and parity judgment tasks within a predictable task…

Automatic-heuristic and executive-analytic processing during reasoning: Chronometric and dual-task considerations.

PubMed

De Neys, Wim

2006-06-01

Human reasoning has been shown to overly rely on intuitive, heuristic processing instead of a more demanding analytic inference process. Four experiments tested the central claim of current dual-process theories that analytic operations involve time-consuming executive processing whereas the heuristic system would operate automatically. Participants solved conjunction fallacy problems and indicative and deontic selection tasks. Experiment 1 established that making correct analytic inferences demanded more processing time than did making heuristic inferences. Experiment 2 showed that burdening the executive resources with an attention-demanding secondary task decreased correct, analytic responding and boosted the rate of conjunction fallacies and indicative matching card selections. Results were replicated in Experiments 3 and 4 with a different secondary-task procedure. Involvement of executive resources for the deontic selection task was less clear. Findings validate basic processing assumptions of the dual-process framework and complete the correlational research programme of K. E. Stanovich and R. F. West (2000).

Word Frequency Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger W.; McCann, Robert S.; VanSelst, Mark; Shafto, Michael G. (Technical Monitor)

1997-01-01

Word frequency effects in dual-task lexical decision are variously reported to be additive or underadditive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again, we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

Word Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger; McCann, Robert S.; VanSelst, Mark; Shafto, Michael (Technical Monitor)

1997-01-01

Word frequency effects in dual-task, lexical decision are variously reported to be additive or under-additive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

Recruiting Conventional Tree Architecture Models into State-of-the-Art LiDAR Mapping for Investigating Tree Growth Habits in Structure.

PubMed

Lin, Yi; Jiang, Miao; Pellikka, Petri; Heiskanen, Janne

2018-01-01

Mensuration of tree growth habits is of considerable importance for understanding forest ecosystem processes and forest biophysical responses to climate changes. However, the complexity of tree crown morphology that is typically formed after many years of growth tends to render it a non-trivial task, even for the state-of-the-art 3D forest mapping technology-light detection and ranging (LiDAR). Fortunately, botanists have deduced the large structural diversity of tree forms into only a limited number of tree architecture models, which can present a-priori knowledge about tree structure, growth, and other attributes for different species. This study attempted to recruit Hallé architecture models (HAMs) into LiDAR mapping to investigate tree growth habits in structure. First, following the HAM-characterized tree structure organization rules, we run the kernel procedure of tree species classification based on the LiDAR-collected point clouds using a support vector machine classifier in the leave-one-out-for-cross-validation mode. Then, the HAM corresponding to each of the classified tree species was identified based on expert knowledge, assisted by the comparison of the LiDAR-derived feature parameters. Next, the tree growth habits in structure for each of the tree species were derived from the determined HAM. In the case of four tree species growing in the boreal environment, the tests indicated that the classification accuracy reached 85.0%, and their growth habits could be derived by qualitative and quantitative means. Overall, the strategy of recruiting conventional HAMs into LiDAR mapping for investigating tree growth habits in structure was validated, thereby paving a new way for efficiently reflecting tree growth habits and projecting forest structure dynamics.

Recruiting Conventional Tree Architecture Models into State-of-the-Art LiDAR Mapping for Investigating Tree Growth Habits in Structure

PubMed Central

Lin, Yi; Jiang, Miao; Pellikka, Petri; Heiskanen, Janne

2018-01-01

Mensuration of tree growth habits is of considerable importance for understanding forest ecosystem processes and forest biophysical responses to climate changes. However, the complexity of tree crown morphology that is typically formed after many years of growth tends to render it a non-trivial task, even for the state-of-the-art 3D forest mapping technology—light detection and ranging (LiDAR). Fortunately, botanists have deduced the large structural diversity of tree forms into only a limited number of tree architecture models, which can present a-priori knowledge about tree structure, growth, and other attributes for different species. This study attempted to recruit Hallé architecture models (HAMs) into LiDAR mapping to investigate tree growth habits in structure. First, following the HAM-characterized tree structure organization rules, we run the kernel procedure of tree species classification based on the LiDAR-collected point clouds using a support vector machine classifier in the leave-one-out-for-cross-validation mode. Then, the HAM corresponding to each of the classified tree species was identified based on expert knowledge, assisted by the comparison of the LiDAR-derived feature parameters. Next, the tree growth habits in structure for each of the tree species were derived from the determined HAM. In the case of four tree species growing in the boreal environment, the tests indicated that the classification accuracy reached 85.0%, and their growth habits could be derived by qualitative and quantitative means. Overall, the strategy of recruiting conventional HAMs into LiDAR mapping for investigating tree growth habits in structure was validated, thereby paving a new way for efficiently reflecting tree growth habits and projecting forest structure dynamics. PMID:29515616

Ecological factors influencing growth of the endangered Hawaiian fern Marsilea villosa (Marsileaceae) and implications for conservation management.

PubMed

Chau, Marian M; Reyes, Whitney R; Ranker, Tom A

2013-08-01

Conserving endangered plants is a complex task, and practitioners must often use a "triage" approach, addressing only immediate needs. Ecologists can improve this process by conducting sound science upon which to base management. Marsilea villosa is an endangered, endemic Hawaiian fern with seven remaining populations in ephemerally flooding drylands. Among its uncommon traits are long-lived sporocarps, requiring flood and drought to complete its sexual life cycle, and extensive vegetative growth. We conducted a 3-yr ecological field study, measuring percent cover of M. villosa and associated species, flooding depth, and canopy cover, to identify ecological factors with the greatest impact on M. villosa growth. Maximum flooding depth and canopy cover had strong positive relationships with M. villosa growth, and all plots with >50% threshold of either variable reached 100% cover of M. villosa by the end of the study. Interaction effects explained nuances of these relationships, including synergy between the two variables. Percent cover of nonnative functional groups (graminoids and nongraminoids) each had negative relationships with M. villosa growth, but interactions showed that nongraminoid cover was driven by particular species, and that time since flooding had greater influence on M. villosa growth than graminoid cover. We recommend planting reintroduced populations in flood-prone areas with moderate shade, experimental outplanting of native plants with M. villosa, and management of graminoids as a functional group, while nongraminoid management should be species-specific. These practices will promote self-sustaining populations and reduce the need for labor-intensive management.

Photoreceptor Mediated Plant Growth Responses: Implications for Photoreceptor Engineering toward Improved Performance in Crops

PubMed Central

Mawphlang, Ophilia I. L.; Kharshiing, Eros V.

2017-01-01

Rising temperatures during growing seasons coupled with altered precipitation rates presents a challenging task of improving crop productivity for overcoming such altered weather patterns and cater to a growing population. Light is a critical environmental factor that exerts a powerful influence on plant growth and development ranging from seed germination to flowering and fruiting. Higher plants utilize a suite of complex photoreceptor proteins to perceive surrounding red/far-red (phytochromes), blue/UV-A (cryptochromes, phototropins, ZTL/FKF1/LKP2), and UV-B light (UVR8). While genomic studies have also shown that light induces extensive reprogramming of gene expression patterns in plants, molecular genetic studies have shown that manipulation of one or more photoreceptors can result in modification of agronomically beneficial traits. Such information can assist researchers to engineer photoreceptors via genome editing technologies to alter expression or even sensitivity thresholds of native photoreceptors for targeting aspects of plant growth that can confer superior agronomic value to the engineered crops. Here we summarize the agronomically important plant growth processes influenced by photoreceptors in crop species, alongwith the functional interactions between different photoreceptors and phytohormones in regulating these responses. We also discuss the potential utility of synthetic biology approaches in photobiology for improving agronomically beneficial traits of crop plants by engineering designer photoreceptors. PMID:28744290

A Big Data Analysis Approach for Rail Failure Risk Assessment.

PubMed

Jamshidi, Ali; Faghih-Roohi, Shahrzad; Hajizadeh, Siamak; Núñez, Alfredo; Babuska, Robert; Dollevoet, Rolf; Li, Zili; De Schutter, Bart

2017-08-01

Railway infrastructure monitoring is a vital task to ensure rail transportation safety. A rail failure could result in not only a considerable impact on train delays and maintenance costs, but also on safety of passengers. In this article, the aim is to assess the risk of a rail failure by analyzing a type of rail surface defect called squats that are detected automatically among the huge number of records from video cameras. We propose an image processing approach for automatic detection of squats, especially severe types that are prone to rail breaks. We measure the visual length of the squats and use them to model the failure risk. For the assessment of the rail failure risk, we estimate the probability of rail failure based on the growth of squats. Moreover, we perform severity and crack growth analyses to consider the impact of rail traffic loads on defects in three different growth scenarios. The failure risk estimations are provided for several samples of squats with different crack growth lengths on a busy rail track of the Dutch railway network. The results illustrate the practicality and efficiency of the proposed approach. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

Large-area sheet task advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.

1983-01-01

The thermal stress models were used to test the effect of melt level on stress generation and growth velocity. The results indicate that melt level has only small effects on stresses but significant effects on growth velocity. These results are consistent with experimental growth from measured melt levels. A new low-stress design concept is being evaluated with the models. A width-limiting version of the low-stress J460 configuration was tested experimentally with results consistent with the design goals.

Task allocation in a distributed computing system

NASA Technical Reports Server (NTRS)

Seward, Walter D.

1987-01-01

A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

Revisiting Training and Verification Process Implementation for Risk Reduction on New Missions at NASA Jet Propulsion Laboratory

NASA Technical Reports Server (NTRS)

Bryant, Larry W.; Fragoso, Ruth S.

2007-01-01

In 2003 we proposed an effort to develop a core program of standardized training and verification practices and standards against which the implementation of these practices could be measured. The purpose was to provide another means of risk reduction for deep space missions to preclude the likelihood of a repeat of the tragedies of the 1998 Mars missions. We identified six areas where the application of standards and standardization would benefit the overall readiness process for flight projects at JPL. These are Individual Training, Team Training, Interface and Procedure Development, Personnel Certification, Interface and procedure Verification, and Operations Readiness Testing. In this paper we will discuss the progress that has been made in the tasks of developing the proposed infrastructure in each of these areas. Specifically we will address the Position Training and Certification Standards that are now available for each operational position found on our Flight Operations Teams (FOT). We will also discuss the MGSS Baseline Flight Operations Team Training Plan which can be tailored for each new flight project at JPL. As these tasks have been progressing, the climate and emphasis for Training and for V and V at JPL has changed, and we have learned about the expansion, growth, and limitations in the roles of traditional positions at JPL such as the Project's Training Engineer, V and V Engineer, and Operations Engineer. The need to keep a tight rein on budgets has led to a merging and/or reduction in these positions which pose challenges to individual capacities and capabilities. We examine the evolution of these processes and the roles involved while taking a look at the impact or potential impact of our proposed training related infrastructure tasks. As we conclude our examination of the changes taking place for new flight projects, we see that the importance of proceeding with our proposed tasks and adapting them to the changing climate remains an important element in reducing the risk in the challenging business of space exploration.

Response Style Differences in the Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Derefinko, Karen J.; Adams, Zachary W.; Milich, Richard; Fillmore, Mark T.; Lorch, Elizabeth P.; Lynam, Donald R.

2008-01-01

This study examined potential differences between the inattentive and combined ADHD subtypes using laboratory tasks assessing behavioral inhibitory processes. Seventy-five children completed two tasks of behavioral inhibition believed to isolate different processes: the cued reaction time task (CRT), a basic inhibition task, and the go/no-go task…

The Influence of Reward Associations on Conflict Processing in the Stroop Task

ERIC Educational Resources Information Center

Krebs, Ruth M.; Boehler, Carsten N.; Woldorff, Marty G.

2010-01-01

Performance in a behavioral task can be facilitated by associating stimulus properties with reward. In contrast, conflicting information is known to impede task performance. Here we investigated how reward associations influence the within-trial processing of conflicting information using a color-naming Stroop task in which a subset of ink colors…

Dilution: A Theoretical Burden or Just Load? A Reply to Tsal and Benoni (2010)

ERIC Educational Resources Information Center

Lavie, Nilli; Torralbo, Ana

2010-01-01

Load theory of attention proposes that distractor processing is reduced in tasks with high perceptual load that exhaust attentional capacity within task-relevant processing. In contrast, tasks of low perceptual load leave spare capacity that spills over, resulting in the perception of task-irrelevant, potentially distracting stimuli. Tsal and…

Vocabulary Growth in Armenian-English Bilingual Kindergarteners

ERIC Educational Resources Information Center

Hovsepian, Alice

2018-01-01

Four-year-old (n = 20) and five-year-old (n = 22) bilingual children were tested twice in six months on Armenian (minority language) and English (majority language) picture identification and picture naming tasks to examine receptive and expressive vocabulary growth in both languages. Parental education, Armenian/English language exposure, and…

Domain-Specific and Unspecific Reaction Times in Experienced Team Handball Goalkeepers and Novices

PubMed Central

Helm, Fabian; Reiser, Mathias; Munzert, Jörn

2016-01-01

In our everyday environments, we are constantly having to adapt our behavior to changing conditions. Hence, processing information is a fundamental cognitive activity, especially the linking together of perceptual and action processes. In this context, expertise research in the sport domain has concentrated on arguing that superior processing performance is driven by an advantage to be found in anticipatory processes (see Williams et al., 2011, for a review). This has resulted in less attention being paid to the benefits coming from basic internal perceptual-motor processing. In general, research on reaction time (RT) indicates that practicing a RT task leads to an increase in processing speed (Mowbray and Rhoades, 1959; Rabbitt and Banerji, 1989). Against this background, the present study examined whether the speed of internal processing is dependent on or independent from domain-specific motor expertise in unpredictable stimulus–response tasks and in a double stimulus–response paradigm. Thirty male participants (15 team handball goalkeepers and 15 novices) performed domain-unspecific simple or choice stimulus–response (CSR) tasks as well as CSR tasks that were domain-specific only for goalkeepers. As expected, results showed significantly faster RTs for goalkeepers on domain-specific tasks, whereas novices’ RTs were more frequently excessively long. However, differences between groups in the double stimulus-response paradigm were not significant. It is concluded that the reported expertise advantage might be due to recalling stored perceptual-motor representations for the domain-specific tasks, implying that experience with (practice of) a motor task explicitly enhances the internal processing of other related domain-specific tasks. PMID:27445879

Domain-Specific and Unspecific Reaction Times in Experienced Team Handball Goalkeepers and Novices.

PubMed

Helm, Fabian; Reiser, Mathias; Munzert, Jörn

2016-01-01

In our everyday environments, we are constantly having to adapt our behavior to changing conditions. Hence, processing information is a fundamental cognitive activity, especially the linking together of perceptual and action processes. In this context, expertise research in the sport domain has concentrated on arguing that superior processing performance is driven by an advantage to be found in anticipatory processes (see Williams et al., 2011, for a review). This has resulted in less attention being paid to the benefits coming from basic internal perceptual-motor processing. In general, research on reaction time (RT) indicates that practicing a RT task leads to an increase in processing speed (Mowbray and Rhoades, 1959; Rabbitt and Banerji, 1989). Against this background, the present study examined whether the speed of internal processing is dependent on or independent from domain-specific motor expertise in unpredictable stimulus-response tasks and in a double stimulus-response paradigm. Thirty male participants (15 team handball goalkeepers and 15 novices) performed domain-unspecific simple or choice stimulus-response (CSR) tasks as well as CSR tasks that were domain-specific only for goalkeepers. As expected, results showed significantly faster RTs for goalkeepers on domain-specific tasks, whereas novices' RTs were more frequently excessively long. However, differences between groups in the double stimulus-response paradigm were not significant. It is concluded that the reported expertise advantage might be due to recalling stored perceptual-motor representations for the domain-specific tasks, implying that experience with (practice of) a motor task explicitly enhances the internal processing of other related domain-specific tasks.

Visual scanning with or without spatial uncertainty and time-sharing performance

NASA Technical Reports Server (NTRS)

Liu, Yili; Wickens, Christopher D.

1989-01-01

An experiment is reported that examines the pattern of task interference between visual scanning as a sequential and selective attention process and other concurrent spatial or verbal processing tasks. A distinction is proposed between visual scanning with or without spatial uncertainty regarding the possible differential effects of these two types of scanning on interference with other concurrent processes. The experiment required the subject to perform a simulated primary tracking task, which was time-shared with a secondary spatial or verbal decision task. The relevant information that was needed to perform the decision tasks were displayed with or without spatial uncertainty. The experiment employed a 2 x 2 x 2 design with types of scanning (with or without spatial uncertainty), expected scanning distance (low/high), and codes of concurrent processing (spatial/verbal) as the three experimental factors. The results provide strong evidence that visual scanning as a spatial exploratory activity produces greater task interference with concurrent spatial tasks than with concurrent verbal tasks. Furthermore, spatial uncertainty in visual scanning is identified to be the crucial factor in producing this differential effect.

Neurofunctional Differences Associated with Arithmetic Processing in Turner Syndrome

PubMed Central

Kesler, Shelli R.; Menon, Vinod; Reiss, Allan L.

2011-01-01

Turner syndrome (TS) is a neurogenetic disorder characterized by the absence of one X chromosome in a phenotypic female. Individuals with TS are at risk for impairments in mathematics. We investigated the neural mechanisms underlying arithmetic processing in TS. Fifteen subjects with TS and 15 age-matched typically developing controls were scanned using functional MRI while they performed easy (two-operand) and difficult (three-operand) versions of an arithmetic processing task. Both groups activated fronto-parietal regions involved in arithmetic processing during the math tasks. Compared with controls, the TS group recruited additional neural resources in frontal and parietal regions during the easier, two-operand math task. During the more difficult three-operand task, individuals with TS demonstrated significantly less activation in frontal, parietal and subcortical regions than controls. However, the TS group’s performance on both math tasks was comparable to controls. Individuals with TS demonstrate activation differences in fronto-parietal areas during arithmetic tasks compared with controls. They must recruit additional brain regions during a relatively easy task and demonstrate a potentially inefficient response to increased task difficulty compared with controls. PMID:16135780

Effects of task demands on the early neural processing of fearful and happy facial expressions

PubMed Central

Itier, Roxane J.; Neath-Tavares, Karly N.

2017-01-01

Task demands shape how we process environmental stimuli but their impact on the early neural processing of facial expressions remains unclear. In a within-subject design, ERPs were recorded to the same fearful, happy and neutral facial expressions presented during a gender discrimination, an explicit emotion discrimination and an oddball detection tasks, the most studied tasks in the field. Using an eye tracker, fixation on the face nose was enforced using a gaze-contingent presentation. Task demands modulated amplitudes from 200–350ms at occipito-temporal sites spanning the EPN component. Amplitudes were more negative for fearful than neutral expressions starting on N170 from 150–350ms, with a temporo-occipital distribution, whereas no clear effect of happy expressions was seen. Task and emotion effects never interacted in any time window or for the ERP components analyzed (P1, N170, EPN). Thus, whether emotion is explicitly discriminated or irrelevant for the task at hand, neural correlates of fearful and happy facial expressions seem immune to these task demands during the first 350ms of visual processing. PMID:28315309

The Effect of Occupational Growth on Labor Force Task Characteristics.

ERIC Educational Resources Information Center

Szafran, Robert F.

1996-01-01

Examination of changes in 495 occupations from 1950-1990 shows an increased likelihood of tasks with high levels of complexity and social interaction, decreased likelihood of fine or gross motor skills or harsh climatic conditions. There is evidence that jobs have become polarized on the need for fine motor skills and level of social interaction.…

Correlates of Individual, and Age-Related, Differences in Short-Term Learning

ERIC Educational Resources Information Center

Zhang, Zhiyong; Davis, Hasker P.; Salthouse, Timothy A.; Tucker-Drob, Elliot M.

2007-01-01

Latent growth models were applied to data on multitrial verbal and spatial learning tasks from two independent studies. Although significant individual differences in both initial level of performance and subsequent learning were found in both tasks, age differences were found only in mean initial level, and not in mean learning. In neither task…

Encoding and choice in the task span paradigm.

PubMed

Reiman, Kaitlin M; Weaver, Starla M; Arrington, Catherine M

2015-03-01

Cognitive control during sequences of planned behaviors requires both plan-level processes such as generating, maintaining, and monitoring the plan, as well as task-level processes such as selecting, establishing and implementing specific task sets. The task span paradigm (Logan in J Exp Psychol Gen 133:218-236, 2004) combines two common cognitive control paradigms, task switching and working memory span, to investigate the integration of plan-level and task-level processes during control of sequential behavior. The current study expands past task span research to include measures of encoding processes and choice behavior with volitional sequence generation, using the standard task span as well as a novel voluntary task span paradigm. In two experiments, we consider how sequence complexity, defined separately for plan-level and task-level complexity, influences sequence encoding (Experiment 1), sequence choice (Experiment 2), sequence memory, and task performance of planned sequences of action. Results indicate that participants were sensitive to sequence complexity, but that different aspects of behavior are most strongly influenced by different types of complexity. Hierarchical complexity at the plan level best predicts voluntary sequence generation and memory; while switch frequency at the task level best predicts encoding of externally defined sequences and task performance. Furthermore, performance RTs were similar for externally and internally defined plans, whereas memory was improved for internally defined sequences. Finally, participants demonstrated a significant sequence choice bias in the voluntary task span. Consistent with past research on choice behavior, volitional selection of plans was markedly influenced by both the ease of memory and performance.

Feedstock powder processing research needs for additive manufacturing development

DOE PAGES

Anderson, Iver E.; White, Emma M. H.; Dehoff, Ryan

2018-02-01

Additive manufacturing (AM) promises to redesign traditional manufacturing by enabling the ultimate in agility for rapid component design changes in commercial products and for fabricating complex integrated parts. Here, by significantly increasing quality and yield of metallic alloy powders, the pace for design, development, and deployment of the most promising AM approaches can be greatly accelerated, resulting in rapid commercialization of these advanced manufacturing methods. By successful completion of a critical suite of processing research tasks that are intended to greatly enhance gas atomized powder quality and the precision and efficiency of powder production, researchers can help promote continued rapidmore » growth of AM. Finally, other powder-based or spray-based advanced manufacturing methods could also benefit from these research outcomes, promoting the next wave of sustainable manufacturing technologies for conventional and advanced materials.« less

Micro-balance sensor integrated with atomic layer deposition chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinson, Alex B. F.; Libera, Joseph A.; Elam, Jeffrey W.

The invention is directed to QCM measurements in monitoring ALD processes. Previously, significant barriers remain in the ALD processes and accurate execution. To turn this exclusively dedicated in situ technique into a routine characterization method, an integral QCM fixture was developed. This new design is easily implemented on a variety of ALD tools, allows rapid sample exchange, prevents backside deposition, and minimizes both the footprint and flow disturbance. Unlike previous QCM designs, the fast thermal equilibration enables tasks such as temperature-dependent studies and ex situ sample exchange, further highlighting the feasibility of this QCM design for day-to-day use. Finally, themore » in situ mapping of thin film growth rates across the ALD reactor was demonstrated in a popular commercial tool operating in both continuous and quasi-static ALD modes.« less

Cancer Cell Biology: A Student-Centered Instructional Module Exploring the Use of Multimedia to Enrich Interactive, Constructivist Learning of Science

PubMed Central

Bockholt, Susanne M.; West, J. Paige; Bollenbacher, Walter E.

2003-01-01

Multimedia has the potential of providing bioscience education novel learning environments and pedagogy applications to foster student interest, involve students in the research process, advance critical thinking/problem-solving skills, and develop conceptual understanding of biological topics. Cancer Cell Biology, an interactive, multimedia, problem-based module, focuses on how mutations in protooncogenes and tumor suppressor genes can lead to uncontrolled cell proliferation by engaging students as research scientists/physicians with the task of diagnosing the molecular basis of tumor growth for a group of patients. The process of constructing the module, which was guided by scientist and student feedback/responses, is described. The completed module and insights gained from its development are presented as a potential “multimedia pedagogy” for the development of other multimedia science learning environments. PMID:12822037

Feedstock powder processing research needs for additive manufacturing development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Iver E.; White, Emma M. H.; Dehoff, Ryan

Additive manufacturing (AM) promises to redesign traditional manufacturing by enabling the ultimate in agility for rapid component design changes in commercial products and for fabricating complex integrated parts. Here, by significantly increasing quality and yield of metallic alloy powders, the pace for design, development, and deployment of the most promising AM approaches can be greatly accelerated, resulting in rapid commercialization of these advanced manufacturing methods. By successful completion of a critical suite of processing research tasks that are intended to greatly enhance gas atomized powder quality and the precision and efficiency of powder production, researchers can help promote continued rapidmore » growth of AM. Finally, other powder-based or spray-based advanced manufacturing methods could also benefit from these research outcomes, promoting the next wave of sustainable manufacturing technologies for conventional and advanced materials.« less

Information and processes underlying semantic and episodic memory across tasks, items, and individuals.

PubMed

Cox, Gregory E; Hemmer, Pernille; Aue, William R; Criss, Amy H

2018-04-01

The development of memory theory has been constrained by a focus on isolated tasks rather than the processes and information that are common to situations in which memory is engaged. We present results from a study in which 453 participants took part in five different memory tasks: single-item recognition, associative recognition, cued recall, free recall, and lexical decision. Using hierarchical Bayesian techniques, we jointly analyzed the correlations between tasks within individuals-reflecting the degree to which tasks rely on shared cognitive processes-and within items-reflecting the degree to which tasks rely on the same information conveyed by the item. Among other things, we find that (a) the processes involved in lexical access and episodic memory are largely separate and rely on different kinds of information, (b) access to lexical memory is driven primarily by perceptual aspects of a word, (c) all episodic memory tasks rely to an extent on a set of shared processes which make use of semantic features to encode both single words and associations between words, and (d) recall involves additional processes likely related to contextual cuing and response production. These results provide a large-scale picture of memory across different tasks which can serve to drive the development of comprehensive theories of memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Selective attention to task-irrelevant emotional distractors is unaffected by the perceptual load associated with a foreground task.

PubMed

Hindi Attar, Catherine; Müller, Matthias M

2012-01-01

A number of studies have shown that emotionally arousing stimuli are preferentially processed in the human brain. Whether or not this preference persists under increased perceptual load associated with a task at hand remains an open question. Here we manipulated two possible determinants of the attentional selection process, perceptual load associated with a foreground task and the emotional valence of concurrently presented task-irrelevant distractors. As a direct measure of sustained attentional resource allocation in early visual cortex we used steady-state visual evoked potentials (SSVEPs) elicited by distinct flicker frequencies of task and distractor stimuli. Subjects either performed a detection (low load) or discrimination (high load) task at a centrally presented symbol stream that flickered at 8.6 Hz while task-irrelevant neutral or unpleasant pictures from the International Affective Picture System (IAPS) flickered at a frequency of 12 Hz in the background of the stream. As reflected in target detection rates and SSVEP amplitudes to both task and distractor stimuli, unpleasant relative to neutral background pictures more strongly withdrew processing resources from the foreground task. Importantly, this finding was unaffected by the factor 'load' which turned out to be a weak modulator of attentional processing in human visual cortex.

Does compliance to patient safety tasks improve and sustain when radiotherapy treatment processes are standardized?

PubMed

Simons, Pascale A M; Houben, Ruud; Benders, Jos; Pijls-Johannesma, Madelon; Vandijck, Dominique; Marneffe, Wim; Backes, Huub; Groothuis, Siebren

2014-10-01

To realize safe radiotherapy treatment, processes must be stabilized. Standard operating procedures (SOP's) were expected to stabilize the treatment process and perceived task importance would increase sustainability in compliance. This paper presents the effects on compliance to safety related tasks of a process redesign based on lean principles. Compliance to patient safety tasks was measured by video recording of actual radiation treatment, before (T0), directly after (T1) and 1.5 years after (T2) a process redesign. Additionally, technologists were surveyed on perceived task importance and reported incidents were collected for three half-year periods between 2007 and 2009. Compliance to four out of eleven tasks increased at T1, of which improvements on three sustained (T2). Perceived importance of tasks strongly correlated (0.82) to compliance rates at T2. The two tasks, perceived as least important, presented low base-line compliance, improved (T1), but relapsed at T2. The reported near misses (patient-level not reached) on accelerators increased (P < 0.001) from 144 (2007) to 535 (2009), while the reported misses (patient-level reached) remained constant. Compliance to specific tasks increased after introducing SOP's and improvements sustained after 1.5 years, indicating increased stability. Perceived importance of tasks correlated positively to compliance and sustainability. Raising the perception of task importance is thus crucial to increase compliance. The redesign resulted in increased willingness to report incidents, creating opportunities for patient safety improvement in radiotherapy treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults - A Pilot Study.

PubMed

Heinzel, Stephan; Rimpel, Jérôme; Stelzel, Christine; Rapp, Michael A

2017-01-01

Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60-72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality ( p < 0.05) and the auditory modality ( p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination.

Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults – A Pilot Study

PubMed Central

Heinzel, Stephan; Rimpel, Jérôme; Stelzel, Christine; Rapp, Michael A.

2017-01-01

Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination. PMID:28286477

RACE/A: an architectural account of the interactions between learning, task control, and retrieval dynamics.

PubMed

van Maanen, Leendert; van Rijn, Hedderik; Taatgen, Niels

2012-01-01

This article discusses how sequential sampling models can be integrated in a cognitive architecture. The new theory Retrieval by Accumulating Evidence in an Architecture (RACE/A) combines the level of detail typically provided by sequential sampling models with the level of task complexity typically provided by cognitive architectures. We will use RACE/A to model data from two variants of a picture-word interference task in a psychological refractory period design. These models will demonstrate how RACE/A enables interactions between sequential sampling and long-term declarative learning, and between sequential sampling and task control. In a traditional sequential sampling model, the onset of the process within the task is unclear, as is the number of sampling processes. RACE/A provides a theoretical basis for estimating the onset of sequential sampling processes during task execution and allows for easy modeling of multiple sequential sampling processes within a task. Copyright © 2011 Cognitive Science Society, Inc.

A task-dependent causal role for low-level visual processes in spoken word comprehension.

PubMed

Ostarek, Markus; Huettig, Falk

2017-08-01

It is well established that the comprehension of spoken words referring to object concepts relies on high-level visual areas in the ventral stream that build increasingly abstract representations. It is much less clear whether basic low-level visual representations are also involved. Here we asked in what task situations low-level visual representations contribute functionally to concrete word comprehension using an interference paradigm. We interfered with basic visual processing while participants performed a concreteness task (Experiment 1), a lexical-decision task (Experiment 2), and a word class judgment task (Experiment 3). We found that visual noise interfered more with concrete versus abstract word processing, but only when the task required visual information to be accessed. This suggests that basic visual processes can be causally involved in language comprehension, but that their recruitment is not automatic and rather depends on the type of information that is required in a given task situation. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

No Evidence for Temporal Decay in Working Memory

ERIC Educational Resources Information Center

Lewandowsky, Stephan; Oberauer, Klaus

2009-01-01

What drives forgetting in working memory? Recent evidence suggests that in a complex-span task in which an irrelevant processing task alternates with presentation of the memoranda, recall declines when the time taken to complete the processing task is extended while holding the time for rehearsal in between processing steps constant (Portrat,…

Memory Indexing: A Novel Method for Tracing Memory Processes in Complex Cognitive Tasks

ERIC Educational Resources Information Center

Renkewitz, Frank; Jahn, Georg

2012-01-01

We validate an eye-tracking method applicable for studying memory processes in complex cognitive tasks. The method is tested with a task on probabilistic inferences from memory. It provides valuable data on the time course of processing, thus clarifying previous results on heuristic probabilistic inference. Participants learned cue values of…

Flexible establishment of functional brain networks supports attentional modulation of unconscious cognition.

PubMed

Ulrich, Martin; Adams, Sarah C; Kiefer, Markus

2014-11-01

In classical theories of attention, unconscious automatic processes are thought to be independent of higher-level attentional influences. Here, we propose that unconscious processing depends on attentional enhancement of task-congruent processing pathways implemented by a dynamic modulation of the functional communication between brain regions. Using functional magnetic resonance imaging, we tested our model with a subliminally primed lexical decision task preceded by an induction task preparing either a semantic or a perceptual task set. Subliminal semantic priming was significantly greater after semantic compared to perceptual induction in ventral occipito-temporal (vOT) and inferior frontal cortex, brain areas known to be involved in semantic processing. The functional connectivity pattern of vOT varied depending on the induction task and successfully predicted the magnitude of behavioral and neural priming. Together, these findings support the proposal that dynamic establishment of functional networks by task sets is an important mechanism in the attentional control of unconscious processing. © 2014 Wiley Periodicals, Inc.

Closed head injury and perceptual processing in dual-task situations.

PubMed

Hein, G; Schubert, T; von Cramon, D Y

2005-01-01

Using a classical psychological refractory period (PRP) paradigm we investigated whether increased interference between dual-task input processes is one possible source of dual-task deficits in patients with closed-head injury (CHI). Patients and age-matched controls were asked to give speeded motor reactions to an auditory and a visual stimulus. The perceptual difficulty of the visual stimulus was manipulated by varying its intensity. The results of Experiment 1 showed that CHI patients suffer from increased interference between dual-task input processes, which is related to the salience of the visual stimulus. A second experiment indicated that this input interference may be specific to brain damage following CHI. It is not evident in other groups of neurological patients like Parkinson's disease patients. We conclude that the non-interfering processing of input stages in dual-tasks requires cognitive control. A decline in the control of input processes should be considered as one source of dual-task deficits in CHI patients.

Predictors of Processing-Based Task Performance in Bilingual and Monolingual Children

PubMed Central

Buac, Milijana; Gross, Megan; Kaushanskaya, Margarita

2016-01-01

In the present study we examined performance of bilingual Spanish-English-speaking and monolingual English-speaking school-age children on a range of processing-based measures within the framework of Baddeley’s working memory model. The processing-based measures included measures of short-term memory, measures of working memory, and a novel word-learning task. Results revealed that monolinguals outperformed bilinguals on the short-term memory tasks but not the working memory and novel word-learning tasks. Further, children’s vocabulary skills and socioeconomic status (SES) were more predictive of processing-based task performance in the bilingual group than the monolingual group. Together, these findings indicate that processing-based tasks that engage verbal working memory rather than short-term memory may be better-suited for diagnostic purposes with bilingual children. However, even verbal working memory measures are sensitive to bilingual children’s language-specific knowledge and demographic characteristics, and therefore may have limited clinical utility. PMID:27179914

It's about time: revisiting temporal processing deficits in dyslexia.

PubMed

Casini, Laurence; Pech-Georgel, Catherine; Ziegler, Johannes C

2018-03-01

Temporal processing in French children with dyslexia was evaluated in three tasks: a word identification task requiring implicit temporal processing, and two explicit temporal bisection tasks, one in the auditory and one in the visual modality. Normally developing children matched on chronological age and reading level served as a control group. Children with dyslexia exhibited robust deficits in temporal tasks whether they were explicit or implicit and whether they involved the auditory or the visual modality. First, they presented larger perceptual variability when performing temporal tasks, whereas they showed no such difficulties when performing the same task on a non-temporal dimension (intensity). This dissociation suggests that their difficulties were specific to temporal processing and could not be attributed to lapses of attention, reduced alertness, faulty anchoring, or overall noisy processing. In the framework of cognitive models of time perception, these data point to a dysfunction of the 'internal clock' of dyslexic children. These results are broadly compatible with the recent temporal sampling theory of dyslexia. © 2017 John Wiley & Sons Ltd.

Cognitive consequences of clumsy automation on high workload, high consequence human performance

NASA Technical Reports Server (NTRS)

Cook, Richard I.; Woods, David D.; Mccolligan, Elizabeth; Howie, Michael B.

1991-01-01

The growth of computational power has fueled attempts to automate more of the human role in complex problem solving domains, especially those where system faults have high consequences and where periods of high workload may saturate the performance capacity of human operators. Examples of these domains include flightdecks, space stations, air traffic control, nuclear power operation, ground satellite control rooms, and surgical operating rooms. Automation efforts may have unanticipated effects on human performance, particularly if they increase the workload at peak workload times or change the practitioners' strategies for coping with workload. Smooth and effective changes in automation requires detailed understanding of the congnitive tasks confronting the user: it has been called user centered automation. The introduction of a new computerized technology in a group of hospital operating rooms used for heart surgery was observed. The study revealed how automation, especially 'clumsy automation', effects practitioner work patterns and suggest that clumsy automation constrains users in specific and significant ways. Users tailor both the new system and their tasks in order to accommodate the needs of process and production. The study of this tailoring may prove a powerful tool for exposing previously hidden patterns of user data processing, integration, and decision making which may, in turn, be useful in the design of more effective human-machine systems.

Central ghrelin increases anxiety in the Open Field test and impairs retention memory in a passive avoidance task in neonatal chicks.

PubMed

Carvajal, Pedro; Carlini, Valeria P; Schiöth, Helgi B; de Barioglio, Susana R; Salvatierra, Nancy A

2009-05-01

Ghrelin (Grh) is an endogenous ligand for the growth hormone secretagogue receptor. Although Ghr stimulates feeding in rats, it inhibits feeding in neonatal chicks. However, little is known about other central behavioral effects of Ghr. Therefore, we investigated the Ghr effects, injected intracerebroventricularly, on anxiety and memory retention of neonatal chicks in an Open Field test and in a one-trial passive avoidance task, respectively. In the Open Field test, the administration of Ghr in a dose-dependent manner increased the latency to ambulate but decreased ambulation activity, indicating an anxiogenic effect. Furthermore, chicks trained on a passive avoidance task and injected with a dose of 30pmol of Ghr immediately after training showed an impairment of memory retention. However, there were no significant effects on the number of pecks during the pretraining, training, retention and discrimination. In addition, different doses of Ghr produced an inhibition in food intake at different times after injection. Our results indicate that Ghr induces anxiogenesis in chicks. Moreover, we have shown for the first time that Ghr can decrease memory retention in a non-mammalian species, suggesting that Ghr may play an important role in the processes of memory retention in birds.

Initiating an ergonomic analysis. A process for jobs with highly variable tasks.

PubMed

Conrad, K M; Lavender, S A; Reichelt, P A; Meyer, F T

2000-09-01

Occupational health nurses play a vital role in addressing ergonomic problems in the workplace. Describing and documenting exposure to ergonomic risk factors is a relatively straightforward process in jobs in which the work is repetitive. In other types of work, the analysis becomes much more challenging because tasks may be repeated infrequently, or at irregular time intervals, or under different environmental and temporal conditions, thereby making it difficult to observe a "representative" sample of the work performed. This article describes a process used to identify highly variable job tasks for ergonomic analyses. The identification of tasks for ergonomic analysis was a two step process involving interviews and a survey of firefighters and paramedics from a consortium of 14 suburban fire departments. The interviews were used to generate a list of frequently performed, physically strenuous job tasks and to capture clear descriptions of those tasks and associated roles. The goals of the survey were to confirm the interview findings across the entire target population and to quantify the frequency and degree of strenuousness of each task. In turn, the quantitative results from the survey were used to prioritize job tasks for simulation. Although this process was used to study firefighters and paramedics, the approach is likely to be suitable for many other types of occupations in which the tasks are highly variable in content and irregular in frequency.

Curriculum-Based Measurement of Oral Reading: An Evaluation of Growth Rates and Seasonal Effects among Students Served in General and Special Education

ERIC Educational Resources Information Center

Christ, Theodore J.; Silberglitt, Benjamin; Yeo, Seungsoo; Cormier, Damien

2010-01-01

Curriculum-based measurement of oral reading (CBM-R) is often used to benchmark growth in the fall, winter, and spring. CBM-R is also used to set goals and monitor student progress between benchmarking occasions. The results of previous research establish an expectation that weekly growth on CBM-R tasks is consistently linear throughout the…

Task-Dependent Masked Priming Effects in Visual Word Recognition

PubMed Central

Kinoshita, Sachiko; Norris, Dennis

2012-01-01

A method used widely to study the first 250 ms of visual word recognition is masked priming: These studies have yielded a rich set of data concerning the processes involved in recognizing letters and words. In these studies, there is an implicit assumption that the early processes in word recognition tapped by masked priming are automatic, and masked priming effects should therefore be invariant across tasks. Contrary to this assumption, masked priming effects are modulated by the task goal: For example, only word targets show priming in the lexical decision task, but both words and non-words do in the same-different task; semantic priming effects are generally weak in the lexical decision task but are robust in the semantic categorization task. We explain how such task dependence arises within the Bayesian Reader account of masked priming (Norris and Kinoshita, 2008), and how the task dissociations can be used to understand the early processes in lexical access. PMID:22675316

Testing the distinctiveness of visual imagery and motor imagery in a reach paradigm.

PubMed

Gabbard, Carl; Ammar, Diala; Cordova, Alberto

2009-01-01

We examined the distinctiveness of motor imagery (MI) and visual imagery (VI) in the context of perceived reachability. The aim was to explore the notion that the two visual modes have distinctive processing properties tied to the two-visual-system hypothesis. The experiment included an interference tactic whereby participants completed two tasks at the same time: a visual or motor-interference task combined with a MI or VI-reaching task. We expected increased error would occur when the imaged task and the interference task were matched (e.g., MI with the motor task), suggesting an association based on the assumption that the two tasks were in competition for space on the same processing pathway. Alternatively, if there were no differences, dissociation could be inferred. Significant increases in the number of errors were found when the modalities for the imaged (both MI and VI) task and the interference task were matched. Therefore, it appears that MI and VI in the context of perceived reachability recruit different processing mechanisms.

Individual variation in hemispheric asymmetry: multitask study of effects related to handedness and sex.

PubMed

Hellige, J B; Bloch, M I; Cowin, E L; Eng, T L; Eviatar, Z; Sergent, V

1994-09-01

Functional hemispheric asymmetries were examined for right- or left-handed men and women. Tasks involved (a) auditory processing of verbal material, (b) processing of emotions shown on faces, (c) processing of visual categorical and coordinate spatial relations, and (d) visual processing of verbal material. Similar performance asymmetries were found for the right-handed and left-handed groups, but the average asymmetries tended to be smaller for the left-handed group. For the most part, measures of performance asymmetry obtained from the different tasks did not correlate with each other, suggesting that individual subjects cannot be simply characterized as strongly or weakly lateralized. However, ear differences obtained in Task 1 did correlate significantly with certain visual field differences obtained in Task 4, suggesting that both tasks are sensitive to hemispheric asymmetry in similar phonetic or language-related processes.

A visual processing advantage for young-adolescent deaf observers: Evidence from face and object matching tasks

PubMed Central

Megreya, Ahmed M.; Bindemann, Markus

2017-01-01

It is unresolved whether the permanent auditory deprivation that deaf people experience leads to the enhanced visual processing of faces. The current study explored this question with a matching task in which observers searched for a target face among a concurrent lineup of ten faces. This was compared with a control task in which the same stimuli were presented upside down, to disrupt typical face processing, and an object matching task. A sample of young-adolescent deaf observers performed with higher accuracy than hearing controls across all of these tasks. These results clarify previous findings and provide evidence for a general visual processing advantage in deaf observers rather than a face-specific effect. PMID:28117407

The speed of information processing of 9- to 13-year-old intellectually gifted children.

PubMed

Duan, Xiaoju; Dan, Zhou; Shi, Jiannong

2013-02-01

In general, intellectually gifted children perform better than non-gifted children across many domains. The present validation study investigated the speed with which intellectually gifted children process information. 184 children, ages 9 to 13 years old (91 gifted, M age = 10.9 yr., SD = 1.8; 93 non-gifted children, M age = 11.0 yr., SD = 1.7) were tested individually on three information processing tasks: an inspection time task, a choice reaction time task, an abstract matching task. Intellectually gifted children outperformed their non-gifted peers on all three tasks obtaining shorter reaction time and doing so with greater accuracy. The findings supported the validity of the information processing speed in identifying intellectually gifted children.

Neural substrates of cognitive switching and inhibition in a face processing task.

PubMed

Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin; Cojan, Yann; Bertschy, Gilles; Vuilleumier, Patrik

2013-11-15

We frequently need to change our current occupation, an operation requiring additional effortful cognitive demands. Switching from one task to another may involve two distinct processes: inhibition of the previously relevant task-set, and initiation of a new one. Here we tested whether these two processes are underpinned by separate neural substrates, and whether they differ depending on the nature of the task and the emotional content of stimuli. We used functional magnetic resonance imaging in healthy human volunteers who categorize emotional faces according to three different judgment rules (color, gender, or emotional expression). Our paradigm allowed us to separate neural activity associated with inhibition and switching based on the sequence of the tasks required on successive trials. We found that the bilateral medial superior parietal lobule and left intraparietal sulcus showed consistent activation during switching regardless of the task. On the other hand, no common region was activated (or suppressed) as a consequence of inhibition across all tasks. Rather, task-specific effects were observed in brain regions that were more activated when switching to a particular task but less activated after inhibition of the same task. In addition, compared to other conditions, the emotional task elicited a similar switching cost but lower inhibition cost, accompanied by selective decrease in the anterior cingulate cortex when returning to this task shortly after inhibiting it. These results demonstrate that switching relies on domain-general processes mediated by postero-medial parietal areas, engaged across all tasks, but also provide novel evidence that task inhibition produces domain-specific decreases as a function of particular task demands, with only the latter inhibition component being modulated by emotional information. Copyright © 2013 Elsevier Inc. All rights reserved.

A multi-site cognitive task analysis for biomedical query mediation.

PubMed

Hruby, Gregory W; Rasmussen, Luke V; Hanauer, David; Patel, Vimla L; Cimino, James J; Weng, Chunhua

2016-09-01

To apply cognitive task analyses of the Biomedical query mediation (BQM) processes for EHR data retrieval at multiple sites towards the development of a generic BQM process model. We conducted semi-structured interviews with eleven data analysts from five academic institutions and one government agency, and performed cognitive task analyses on their BQM processes. A coding schema was developed through iterative refinement and used to annotate the interview transcripts. The annotated dataset was used to reconstruct and verify each BQM process and to develop a harmonized BQM process model. A survey was conducted to evaluate the face and content validity of this harmonized model. The harmonized process model is hierarchical, encompassing tasks, activities, and steps. The face validity evaluation concluded the model to be representative of the BQM process. In the content validity evaluation, out of the 27 tasks for BQM, 19 meet the threshold for semi-valid, including 3 fully valid: "Identify potential index phenotype," "If needed, request EHR database access rights," and "Perform query and present output to medical researcher", and 8 are invalid. We aligned the goals of the tasks within the BQM model with the five components of the reference interview. The similarity between the process of BQM and the reference interview is promising and suggests the BQM tasks are powerful for eliciting implicit information needs. We contribute a BQM process model based on a multi-site study. This model promises to inform the standardization of the BQM process towards improved communication efficiency and accuracy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A Multi-Site Cognitive Task Analysis for Biomedical Query Mediation

PubMed Central

Hruby, Gregory W.; Rasmussen, Luke V.; Hanauer, David; Patel, Vimla; Cimino, James J.; Weng, Chunhua

2016-01-01

Objective To apply cognitive task analyses of the Biomedical query mediation (BQM) processes for EHR data retrieval at multiple sites towards the development of a generic BQM process model. Materials and Methods We conducted semi-structured interviews with eleven data analysts from five academic institutions and one government agency, and performed cognitive task analyses on their BQM processes. A coding schema was developed through iterative refinement and used to annotate the interview transcripts. The annotated dataset was used to reconstruct and verify each BQM process and to develop a harmonized BQM process model. A survey was conducted to evaluate the face and content validity of this harmonized model. Results The harmonized process model is hierarchical, encompassing tasks, activities, and steps. The face validity evaluation concluded the model to be representative of the BQM process. In the content validity evaluation, out of the 27 tasks for BQM, 19 meet the threshold for semi-valid, including 3 fully valid: “Identify potential index phenotype,” “If needed, request EHR database access rights,” and “Perform query and present output to medical researcher”, and 8 are invalid. Discussion We aligned the goals of the tasks within the BQM model with the five components of the reference interview. The similarity between the process of BQM and the reference interview is promising and suggests the BQM tasks are powerful for eliciting implicit information needs. Conclusions We contribute a BQM process model based on a multi-site study. This model promises to inform the standardization of the BQM process towards improved communication efficiency and accuracy. PMID:27435950

Impaired holistic processing in congenital prosopagnosia

PubMed Central

Avidan, Galia; Tanzer, Michal; Behrmann, Marlene

2011-01-01

It has long been argued that face processing requires disproportionate reliance on holistic or configural processing, relative to that required for non-face object recognition, and that a disruption of such holistic processing may be causally implicated in prosopagnosia. Previously, we demonstrated that individuals with congenital prosopagnosia (CP) did not show the normal face inversion effect (better performance for upright compared to inverted faces) and evinced a local (rather than the normal global) bias in a compound letter global/local (GL) task, supporting the claim of disrupted holistic processing in prosopagnosia. Here, we investigate further the nature of holistic processing impairments in CP, first by confirming, in a large sample of CP individuals, the absence of the normal face inversion effect and the presence of the local bias on the GL task, and, second, by employing the composite face paradigm, often regarded as the gold standard for measuring holistic face processing. In this last task, we show that, in contrast with normal individuals, the CP group perform equivalently with aligned and misaligned faces and was impervious to (the normal) interference from the task-irrelevant bottom part of faces. Interestingly, the extent of the local bias evident in the composite task is correlated with the abnormality of performance on diagnostic face processing tasks. Furthermore, there is a significant correlation between the magnitude of the local bias in the GL and performance on the composite task. These results provide further evidence for impaired holistic processing in CP and, moreover, corroborate the critical role of this type of processing for intact face recognition. PMID:21601583

Study of Turbofan Engines Designed for Low Enery Consumption

NASA Technical Reports Server (NTRS)

Neitzel, R. E.; Hirschkron, R.; Johnston, R. P.

1976-01-01

Subsonic transport turbofan engine design and technology features which have promise of improving aircraft energy consumption are described. Task I addressed the selection and evaluation of features for the CF6 family of engines in current aircraft, and growth models of these aircraft. Task II involved cycle studies and the evaluation of technology features for advanced technology turbofans, consistent with initial service in 1985. Task III pursued the refined analysis of a specific design of an advanced technology turbofan engine selected as the result of Task II studies. In all of the above, the impact upon aircraft economics, as well as energy consumption, was evaluated. Task IV summarized recommendations for technology developments which would be necessary to achieve the improvements in energy consumption identified.

Tracing children's vocabulary development from preschool through the school-age years: An 8-year longitudinal study

PubMed Central

Kang, Cuiping; Liu, Hongyun; Zhang, Yuping; McBride-Chang, Catherine; Tardif, Twila; Li, Hong; Liang, Weilan; Zhang, Zhixiang; Shu, Hua

2014-01-01

In this 8-year longitudinal study, we traced the vocabulary growth of Chinese children, explored potential precursors of vocabulary knowledge, and investigated how vocabulary growth predicted future reading skills. Two hundred sixty-four (264) native Chinese children from Beijing were measured on a variety of reading and language tasks over 8 years. Between the ages of 4 to 10 years, they were administered tasks of vocabulary and related cognitive skills. At age 11, comprehensive reading skills, including character recognition, reading fluency, and reading comprehension were examined. Individual differences in vocabulary developmental profiles were estimated using the intercept-slope cluster method. Vocabulary development was then examined in relation to later reading outcomes. Three subgroups of lexical growth were classified, namely high-high (with a large initial vocabulary size and a fast growth rate), low-high (with a small initial vocabulary size and a fast growth rate) and low-low (with a small initial vocabulary size and a slow growth rate) groups. Low-high and low-low groups were distinguishable mostly through phonological skills, morphological skills and other reading-related cognitive skills. Childhood vocabulary development (using intercept and slope) explained subsequent reading skills. Findings suggest that language-related and reading-related cognitive skills differ among groups with different developmental trajectories of vocabulary, and the initial size and growth rate of vocabulary may be two predictors for later reading development. PMID:24962559

Tasking and sharing sensing assets using controlled natural language

NASA Astrophysics Data System (ADS)

Preece, Alun; Pizzocaro, Diego; Braines, David; Mott, David

2012-06-01

We introduce an approach to representing intelligence, surveillance, and reconnaissance (ISR) tasks at a relatively high level in controlled natural language. We demonstrate that this facilitates both human interpretation and machine processing of tasks. More specically, it allows the automatic assignment of sensing assets to tasks, and the informed sharing of tasks between collaborating users in a coalition environment. To enable automatic matching of sensor types to tasks, we created a machine-processable knowledge representation based on the Military Missions and Means Framework (MMF), and implemented a semantic reasoner to match task types to sensor types. We combined this mechanism with a sensor-task assignment procedure based on a well-known distributed protocol for resource allocation. In this paper, we re-formulate the MMF ontology in Controlled English (CE), a type of controlled natural language designed to be readable by a native English speaker whilst representing information in a structured, unambiguous form to facilitate machine processing. We show how CE can be used to describe both ISR tasks (for example, detection, localization, or identication of particular kinds of object) and sensing assets (for example, acoustic, visual, or seismic sensors, mounted on motes or unmanned vehicles). We show how these representations enable an automatic sensor-task assignment process. Where a group of users are cooperating in a coalition, we show how CE task summaries give users in the eld a high-level picture of ISR coverage of an area of interest. This allows them to make ecient use of sensing resources by sharing tasks.

The Correlation among Neural Dynamic Processing of Conflict Control, Testosterone and Cortisol Levels in 10-Year-Old Children.

PubMed

Shangguan, Fangfang; Liu, Tongran; Liu, Xiuying; Shi, Jiannong

2017-01-01

Cognitive control is related to goal-directed self-regulation abilities, which is fundamental for human development. Conflict control includes the neural processes of conflict monitoring and conflict resolution. Testosterone and cortisol are essential hormones for the development of cognitive functions. However, there are no studies that have investigated the correlation of these two hormones with conflict control in preadolescents. In this study, we aimed to explore whether testosterone, cortisol, and testosterone/cortisol ratio worked differently for preadolescent's conflict control processes in varied conflict control tasks. Thirty-two 10-year-old children (16 boys and 16 girls) were enrolled. They were instructed to accomplish three conflict control tasks with different conflict dimensions, including the Flanker, Simon, and Stroop tasks, and electrophysiological signals were recorded. Salivary samples were collected from each child. The testosterone and cortisol levels were determined by enzyme-linked immunosorbent assay. The electrophysiological results showed that the incongruent trials induced greater N2/N450 and P3/SP responses than the congruent trials during neural processes of conflict monitoring and conflict resolution in the Flanker and Stroop tasks. The hormonal findings showed that (1) the testosterone/cortisol ratio was correlated with conflict control accuracy and conflict resolution in the Flanker task; (2) the testosterone level was associated with conflict control performance and neural processing of conflict resolution in the Stroop task; (3) the cortisol level was correlated with conflict control performance and neural processing of conflict monitoring in the Simon task. In conclusion, in 10-year-old children, the fewer processes a task needs, the more likely there is an association between the T/C ratios and the behavioral and brain response, and the dual-hormone effects on conflict resolution may be testosterone-driven in the Stroop and Flanker tasks.

Examining a supramodal network for conflict processing: a systematic review and novel functional magnetic resonance imaging data for related visual and auditory stroop tasks.

PubMed

Roberts, Katherine L; Hall, Deborah A

2008-06-01

Cognitive control over conflicting information has been studied extensively using tasks such as the color-word Stroop, flanker, and spatial conflict task. Neuroimaging studies typically identify a fronto-parietal network engaged in conflict processing, but numerous additional regions are also reported. Ascribing putative functional roles to these regions is problematic because some may have less to do with conflict processing per se, but could be engaged in specific processes related to the chosen stimulus modality, stimulus feature, or type of conflict task. In addition, some studies contrast activation on incongruent and congruent trials, even though a neutral baseline is needed to separate the effect of inhibition from that of facilitation. In the first part of this article, we report a systematic review of 34 neuroimaging publications, which reveals that conflict-related activity is reliably reported in the anterior cingulate cortex and bilaterally in the lateral prefrontal cortex, the anterior insula, and the parietal lobe. In the second part, we further explore these candidate "conflict" regions through a novel functional magnetic resonance imaging experiment, in which the same group of subjects perform related visual and auditory Stroop tasks. By carefully controlling for the same task (Stroop), the same to-be-ignored stimulus dimension (word meaning), and by separating out inhibitory processes from those of facilitation, we attempt to minimize the potential differences between the two tasks. The results provide converging evidence that the regions identified by the systematic review are reliably engaged in conflict processing. Despite carefully matching the Stroop tasks, some regions of differential activity remained, particularly in the parietal cortex. We discuss some of the task-specific processes which might account for this finding.

Framework for Integrating Science Data Processing Algorithms Into Process Control Systems

NASA Technical Reports Server (NTRS)

Mattmann, Chris A.; Crichton, Daniel J.; Chang, Albert Y.; Foster, Brian M.; Freeborn, Dana J.; Woollard, David M.; Ramirez, Paul M.

2011-01-01

A software framework called PCS Task Wrapper is responsible for standardizing the setup, process initiation, execution, and file management tasks surrounding the execution of science data algorithms, which are referred to by NASA as Product Generation Executives (PGEs). PGEs codify a scientific algorithm, some step in the overall scientific process involved in a mission science workflow. The PCS Task Wrapper provides a stable operating environment to the underlying PGE during its execution lifecycle. If the PGE requires a file, or metadata regarding the file, the PCS Task Wrapper is responsible for delivering that information to the PGE in a manner that meets its requirements. If the PGE requires knowledge of upstream or downstream PGEs in a sequence of executions, that information is also made available. Finally, if information regarding disk space, or node information such as CPU availability, etc., is required, the PCS Task Wrapper provides this information to the underlying PGE. After this information is collected, the PGE is executed, and its output Product file and Metadata generation is managed via the PCS Task Wrapper framework. The innovation is responsible for marshalling output Products and Metadata back to a PCS File Management component for use in downstream data processing and pedigree. In support of this, the PCS Task Wrapper leverages the PCS Crawler Framework to ingest (during pipeline processing) the output Product files and Metadata produced by the PGE. The architectural components of the PCS Task Wrapper framework include PGE Task Instance, PGE Config File Builder, Config File Property Adder, Science PGE Config File Writer, and PCS Met file Writer. This innovative framework is really the unifying bridge between the execution of a step in the overall processing pipeline, and the available PCS component services as well as the information that they collectively manage.

Non-Interfering Effects of Active Post-Encoding Tasks on Episodic Memory Consolidation in Humans

PubMed Central

Varma, Samarth; Takashima, Atsuko; Krewinkel, Sander; van Kooten, Maaike; Fu, Lily; Medendorp, W. Pieter; Kessels, Roy P. C.; Daselaar, Sander M.

2017-01-01

So far, studies that investigated interference effects of post-learning processes on episodic memory consolidation in humans have used tasks involving only complex and meaningful information. Such tasks require reallocation of general or encoding-specific resources away from consolidation-relevant activities. The possibility that interference can be elicited using a task that heavily taxes our limited brain resources, but has low semantic and hippocampal related long-term memory processing demands, has never been tested. We address this question by investigating whether consolidation could persist in parallel with an active, encoding-irrelevant, minimally semantic task, regardless of its high resource demands for cognitive processing. We distinguish the impact of such a task on consolidation based on whether it engages resources that are: (1) general/executive, or (2) specific/overlapping with the encoding modality. Our experiments compared subsequent memory performance across two post-encoding consolidation periods: quiet wakeful rest and a cognitively demanding n-Back task. Across six different experiments (total N = 176), we carefully manipulated the design of the n-Back task to target general or specific resources engaged in the ongoing consolidation process. In contrast to previous studies that employed interference tasks involving conceptual stimuli and complex processing demands, we did not find any differences between n-Back and rest conditions on memory performance at delayed test, using both recall and recognition tests. Our results indicate that: (1) quiet, wakeful rest is not a necessary prerequisite for episodic memory consolidation; and (2) post-encoding cognitive engagement does not interfere with memory consolidation when task-performance has minimal semantic and hippocampally-based episodic memory processing demands. We discuss our findings with reference to resource and reactivation-led interference theories. PMID:28424596

Non-Interfering Effects of Active Post-Encoding Tasks on Episodic Memory Consolidation in Humans.

PubMed

Varma, Samarth; Takashima, Atsuko; Krewinkel, Sander; van Kooten, Maaike; Fu, Lily; Medendorp, W Pieter; Kessels, Roy P C; Daselaar, Sander M

2017-01-01

So far, studies that investigated interference effects of post-learning processes on episodic memory consolidation in humans have used tasks involving only complex and meaningful information. Such tasks require reallocation of general or encoding-specific resources away from consolidation-relevant activities. The possibility that interference can be elicited using a task that heavily taxes our limited brain resources, but has low semantic and hippocampal related long-term memory processing demands, has never been tested. We address this question by investigating whether consolidation could persist in parallel with an active, encoding-irrelevant, minimally semantic task, regardless of its high resource demands for cognitive processing. We distinguish the impact of such a task on consolidation based on whether it engages resources that are: (1) general/executive, or (2) specific/overlapping with the encoding modality. Our experiments compared subsequent memory performance across two post-encoding consolidation periods: quiet wakeful rest and a cognitively demanding n-Back task. Across six different experiments (total N = 176), we carefully manipulated the design of the n-Back task to target general or specific resources engaged in the ongoing consolidation process. In contrast to previous studies that employed interference tasks involving conceptual stimuli and complex processing demands, we did not find any differences between n-Back and rest conditions on memory performance at delayed test, using both recall and recognition tests. Our results indicate that: (1) quiet, wakeful rest is not a necessary prerequisite for episodic memory consolidation; and (2) post-encoding cognitive engagement does not interfere with memory consolidation when task-performance has minimal semantic and hippocampally-based episodic memory processing demands. We discuss our findings with reference to resource and reactivation-led interference theories.

To speak or not to speak - A multiple resource perspective

NASA Technical Reports Server (NTRS)

Tsang, P. S.; Hartzell, E. J.; Rothschild, R. A.

1985-01-01

The desirability of employing speech response in a dynamic dual task situation was discussed from a multiple resource perspective. A secondary task technique was employed to examine the time-sharing performance of five dual tasks with various degrees of resource overlap according to the structure-specific resource model of Wickens (1980). The primary task was a visual/manual tracking task which required spatial processing. The secondary task was either another tracking task or a spatial transformation task with one of four input (visual or auditory) and output (manual or speech) configurations. The results show that the dual task performance was best when the primary tracking task was paired with the visual/speech transformation task. This finding was explained by an interaction of the stimulus-central processing-response compatibility of the transformation task and the degree of resource competition between the time-shared tasks. Implications on the utility of speech response were discussed.

[Self-judgment of personality traits and cognitive dimensions of the self].

PubMed

Horiuchi, T

1996-12-01

When people make a judgment as to whether a trait describes themselves or not, cognitive structure about the self must play an important role. Cognitive dimensions are a characteristic of such cognitive structure. The present study examined whether a self-referent information processing was mediated by cognitive dimensions of the self. For the purpose, Klein, Loftus, and Burton's task facilitation paradigm (1989) was adapted, which consisted of performing in succession two tasks, initial and target, for each trait adjective used. Experiment 1, which examined the evaluative dimension, showed that an evaluative processing in the target task was facilitated when the initial task was self-referent. Experiment 2, which examined six dimensions, showed that processing of the relevant dimension in the target task was facilitated when the initial task was self-referent. These results suggest that a self-referent information processing is mediated by cognitive dimensions of the self.

Toward a Cognitive Task Analysis for Biomedical Query Mediation

PubMed Central

Hruby, Gregory W.; Cimino, James J.; Patel, Vimla; Weng, Chunhua

2014-01-01

In many institutions, data analysts use a Biomedical Query Mediation (BQM) process to facilitate data access for medical researchers. However, understanding of the BQM process is limited in the literature. To bridge this gap, we performed the initial steps of a cognitive task analysis using 31 BQM instances conducted between one analyst and 22 researchers in one academic department. We identified five top-level tasks, i.e., clarify research statement, explain clinical process, identify related data elements, locate EHR data element, and end BQM with either a database query or unmet, infeasible information needs, and 10 sub-tasks. We evaluated the BQM task model with seven data analysts from different clinical research institutions. Evaluators found all the tasks completely or semi-valid. This study contributes initial knowledge towards the development of a generalizable cognitive task representation for BQM. PMID:25954589

Toward a cognitive task analysis for biomedical query mediation.

PubMed

Hruby, Gregory W; Cimino, James J; Patel, Vimla; Weng, Chunhua

2014-01-01

In many institutions, data analysts use a Biomedical Query Mediation (BQM) process to facilitate data access for medical researchers. However, understanding of the BQM process is limited in the literature. To bridge this gap, we performed the initial steps of a cognitive task analysis using 31 BQM instances conducted between one analyst and 22 researchers in one academic department. We identified five top-level tasks, i.e., clarify research statement, explain clinical process, identify related data elements, locate EHR data element, and end BQM with either a database query or unmet, infeasible information needs, and 10 sub-tasks. We evaluated the BQM task model with seven data analysts from different clinical research institutions. Evaluators found all the tasks completely or semi-valid. This study contributes initial knowledge towards the development of a generalizable cognitive task representation for BQM.

Discerning measures of conscious brain processes associated with superior early motor performance: Capacity, coactivation, and character.

PubMed

van Duijn, Tina; Buszard, Tim; Hoskens, Merel C J; Masters, Rich S W

2017-01-01

This study explored the relationship between working memory (WM) capacity, corticocortical communication (EEG coherence), and propensity for conscious control of movement during the performance of a complex far-aiming task. We were specifically interested in the role of these variables in predicting motor performance by novices. Forty-eight participants completed (a) an assessment of WM capacity (an adapted Rotation Span task), (b) a questionnaire that assessed the propensity to consciously control movement (the Movement Specific Reinvestment Scale), and (c) a hockey push-pass task. The hockey push-pass task was performed in a single task (movement only) condition and a combined task (movement plus decision) condition. Electroencephalography (EEG) was used to examine brain activity during the single task. WM capacity best predicted single task performance. WM capacity in combination with T8-Fz coherence (between the visuospatial and motor regions of the brain) best predicted combined task performance. We discuss the implied roles of visuospatial information processing capacity, neural coactivation, and propensity for conscious processing during performance of complex motor tasks. © 2017 Elsevier B.V. All rights reserved.

Aging and the Vulnerability of Speech to Dual Task Demands

PubMed Central

Kemper, Susan; Schmalzried, RaLynn; Hoffman, Lesa; Herman, Ruth

2010-01-01

Tracking a digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. Tracking performance by both groups was affected by dual task demands: time on target declined and tracking error increased as dual task demands increased from the baseline condition to a moderately demanding dual task condition to a more demanding dual task condition. When dual task demands were moderate, older adults’ speech rate declined but their fluency, grammatical complexity, and content were unaffected. When the dual task was more demanding, older adults’ speech, like young adults’ speech, became highly fragmented, ungrammatical, and incoherent. Vocabulary, working memory, processing speed, and inhibition affected vulnerability to dual task costs: vocabulary provided some protection for sentence length and grammaticality, working memory conferred some protection for grammatical complexity, and processing speed provided some protection for speech rate, propositional density, coherence, and lexical diversity. Further, vocabulary and working memory capacity provided more protection for older adults than for young adults although the protective effect of processing speed was somewhat reduced for older adults as compared to the young adults. PMID:21186917

Rethinking the connection between working memory and language impairment.

PubMed

Archibald, Lisa M D; Harder Griebeling, Katherine

2016-05-01

Working memory deficits have been found for children with specific language impairment (SLI) on tasks imposing increasing short-term memory load with or without additional, consistent (and simple) processing load. To examine the processing function of working memory in children with low language (LL) by employing tasks imposing increasing processing loads with constant storage demands individually adjusted based on each participant's short-term memory capacity. School-age groups with LL (n = 17) and typical language with either average (n = 28) or above-average nonverbal intelligence (n = 15) completed complex working memory-span tasks varying processing load while keeping storage demands constant, varying storage demands while keeping processing load constant, simple storage-span tasks, and measures of language and nonverbal intelligence. Teachers completed questionnaires about cognition and learning. Significantly lower scores were found for the LL than either matched group on storage-based tasks, but no group differences were found on the tasks varying processing load. Teachers' ratings of oral expression and mathematics abilities discriminated those who did or did not complete the most challenging cognitive tasks. The results implicate a deficit in the phonological storage but not in the central executive component of working memory for children with LL. Teacher ratings may reveal personality traits related to perseverance of effort in cognitive research. © 2015 Royal College of Speech and Language Therapists.

The system neurophysiological basis of backward inhibition.

PubMed

Zhang, Rui; Stock, Ann-Kathrin; Fischer, Rico; Beste, Christian

2016-12-01

Task switching is regularly required in our everyday life. To succeed in switching, it is important to inhibit the most recently performed task and instead activate the currently relevant task. The process that inhibits a recently performed task when a new task is to be performed is referred to as 'backward inhibition' (BI). While the BI effect has been subject to intense research in cognitive psychology, little is known about the neuronal mechanisms that are related to the BI effect and those that relate to differences in the magnitude of the BI effect. In the current study, we examined the system neurophysiological basis of BI processes using event-related potentials (ERPs) and sLORETA by also taking inter-individual differences in the magnitude of the BI into account. The results suggest that BI processes and inter-individual differences in them strongly depend upon attentional selection mechanisms (reflected by N1-ERP modulations in the current task/trial) mediated via networks consisting of extrastriate occipital areas, the temporo-parietal junction and the inferior frontal gyrus. Other processes and mechanisms related to conflict monitoring, response selection, or the updating, organization and implementation of a new task-set (i.e. N2 and P3 processes) were not shown to be modulated by BI processes and differences in their magnitude, as evoked with a common BI paradigm.

Impulsive-Reflective Attitude, Behavioural Inhibition and Motor Skills: Are They Linked?

ERIC Educational Resources Information Center

Rosey, Florence; Keller, Jean; Golomer, Eveline

2010-01-01

The present study aims to examine whether the inhibitory processes and impulsive-cognitive style can influence the emergence of coordination level among 61 children aged 3 to 5 years. Luria's tapping tasks, Day-Night tasks, Hand-Candle tasks, Go-NoGo tasks and the Trail Making Tests of Reitan, all involving inhibitory processes, were conducted.…

Approximate Number Sense, Symbolic Number Processing, or Number-Space Mappings: What Underlies Mathematics Achievement?

ERIC Educational Resources Information Center

Sasanguie, Delphine; Gobel, Silke M.; Moll, Kristina; Smets, Karolien; Reynvoet, Bert

2013-01-01

In this study, the performance of typically developing 6- to 8-year-old children on an approximate number discrimination task, a symbolic comparison task, and a symbolic and nonsymbolic number line estimation task was examined. For the first time, children's performances on these basic cognitive number processing tasks were explicitly contrasted…

The Question Shapes the Answer: The Neural Correlates of Task Differences Reveal Dynamic Semantic Processing

ERIC Educational Resources Information Center

Hargreaves, Ian S.; White, Michelle; Pexman, Penny M.; Pittman, Dan; Goodyear, Brad G.

2012-01-01

Task effects in semantic processing were investigated by contrasting the neural activation associated with two semantic categorization tasks (SCT) using event-related fMRI. The two SCTs involved different decision categories: "is it an animal?" vs. "is it a concrete thing?" Participants completed both tasks and, across participants, the same core…

The role of the amygdala and the basal ganglia in visual processing of central vs. peripheral emotional content.

PubMed

Almeida, Inês; van Asselen, Marieke; Castelo-Branco, Miguel

2013-09-01

In human cognition, most relevant stimuli, such as faces, are processed in central vision. However, it is widely believed that recognition of relevant stimuli (e.g. threatening animal faces) at peripheral locations is also important due to their survival value. Moreover, task instructions have been shown to modulate brain regions involved in threat recognition (e.g. the amygdala). In this respect it is also controversial whether tasks requiring explicit focus on stimulus threat content vs. implicit processing differently engage primitive subcortical structures involved in emotional appraisal. Here we have addressed the role of central vs. peripheral processing in the human amygdala using animal threatening vs. non-threatening face stimuli. First, a simple animal face recognition task with threatening and non-threatening animal faces, as well as non-face control stimuli, was employed in naïve subjects (implicit task). A subsequent task was then performed with the same stimulus categories (but different stimuli) in which subjects were told to explicitly detect threat signals. We found lateralized amygdala responses both to the spatial location of stimuli and to the threatening content of faces depending on the task performed: the right amygdala showed increased responses to central compared to left presented stimuli specifically during the threat detection task, while the left amygdala was better prone to discriminate threatening faces from non-facial displays during the animal face recognition task. Additionally, the right amygdala responded to faces during the threat detection task but only when centrally presented. Moreover, we have found no evidence for superior responses of the amygdala to peripheral stimuli. Importantly, we have found that striatal regions activate differentially depending on peripheral vs. central processing of threatening faces. Accordingly, peripheral processing of these stimuli activated more strongly the putaminal region, while central processing engaged mainly the caudate nucleus. We conclude that the human amygdala has a central bias for face stimuli, and that visual processing recruits different striatal regions, putaminal or caudate based, depending on the task and on whether peripheral or central visual processing is involved. © 2013 Elsevier Ltd. All rights reserved.

Individual differences in emotion processing: how similar are diffusion model parameters across tasks?

PubMed

Mueller, Christina J; White, Corey N; Kuchinke, Lars

2017-11-27

The goal of this study was to replicate findings of diffusion model parameters capturing emotion effects in a lexical decision task and investigating whether these findings extend to other tasks of implicit emotion processing. Additionally, we were interested in the stability of diffusion model parameters across emotional stimuli and tasks for individual subjects. Responses to words in a lexical decision task were compared with responses to faces in a gender categorization task for stimuli of the emotion categories: happy, neutral and fear. Main effects of emotion as well as stability of emerging response style patterns as evident in diffusion model parameters across these tasks were analyzed. Based on earlier findings, drift rates were assumed to be more similar in response to stimuli of the same emotion category compared to stimuli of a different emotion category. Results showed that emotion effects of the tasks differed with a processing advantage for happy followed by neutral and fear-related words in the lexical decision task and a processing advantage for neutral followed by happy and fearful faces in the gender categorization task. Both emotion effects were captured in estimated drift rate parameters-and in case of the lexical decision task also in the non-decision time parameters. A principal component analysis showed that contrary to our hypothesis drift rates were more similar within a specific task context than within a specific emotion category. Individual response patterns of subjects across tasks were evident in significant correlations regarding diffusion model parameters including response styles, non-decision times and information accumulation.

Interfering with memory for faces: The cost of doing two things at once.

PubMed

Wammes, Jeffrey D; Fernandes, Myra A

2016-01-01

We inferred the processes critical for episodic retrieval of faces by measuring susceptibility to memory interference from different distracting tasks. Experiment 1 examined recognition of studied faces under full attention (FA) or each of two divided attention (DA) conditions requiring concurrent decisions to auditorily presented letters. Memory was disrupted in both DA relative to FA conditions, a result contrary to a material-specific account of interference effects. Experiment 2 investigated whether the magnitude of interference depended on competition between concurrent tasks for common processing resources. Studied faces were presented either upright (configurally processed) or inverted (featurally processed). Recognition was completed under FA, or DA with one of two face-based distracting tasks requiring either featural or configural processing. We found an interaction: memory for upright faces was lower under DA when the distracting task required configural than featural processing, while the reverse was true for memory of inverted faces. Across experiments, the magnitude of memory interference was similar (a 19% or 20% decline from FA) regardless of whether the materials in the distracting task overlapped with the to-be-remembered information. Importantly, interference was significantly larger (42%) when the processing demands of the distracting and target retrieval task overlapped, suggesting a processing-specific account of memory interference.

Growth outcome: nutritionist perspective.

PubMed

Agostoni, Carlo; Fattore, Giovanni

2013-01-01

Increasing evidence points to a fundamental role of early nutrition on rates of growth and development, and later health. We may identify three major fields of scientific interest and clinical application. (1) In developing countries poor growth is associated with greater risk of morbidity and mortality from infectious diseases, mainly lower respiratory infections and diarrhea. In these settings, failure to promote compensatory growth may have negative short-term consequences, and the nutritionist's task is the primary prevention of nutrient deficiencies to promote the full expression of the individual genetic potential, while allowing for recovery of early secondary functional deficiencies. (2) A second challenge for nutritionists is represented by the approach to growth impairments in rare disorders, ranging from congenital disorders to chronic infections. Most disorders are favorably influenced by improved nutritional status and better growth, and patients may satisfactorily reach adolescence, pubertal and reproductive age, up to ageing. Even for the less positive conditions, an improvement in the quality of life for families is in any case a rewarding aim. (3) A third challenge is represented by the definition of the role of nutrition on growth in physiological conditions for all individuals. Concern has been raised about the potential adverse long-term consequences of accelerated child growth rates, possibly resulting in a predisposition to develop non-communicable chronic diseases in the adult age. Accordingly, this hypothesis might explain the benefits of breastfeeding in terms of slower early growth, and the fetal origins hypothesis in terms of adverse postnatal catch-up growth in infants born small. Therefore, growth as viewed by a pediatric nutritionist perspective is a complex matter, ranging from the early stages of intrauterine development up to adult ages and ageing processes. Cost/benefit analyses of interventions on growth such as cost per DALYs (disability-adjusted life years) or QALYs (quality-adjusted life years) should be expanded on population basis and extended also to congenital and invalidating disorders to identify the most effective and economic sustainable strategies of action. Copyright © 2013 S. Karger AG, Basel.

Numerosity processing is context driven even in the subitizing range: An fMRI study

PubMed Central

Leibovich, Tali; Henik, Avishai; Salti, Moti

2015-01-01

Numerical judgments are involved in almost every aspect of our daily life. They are carried out so efficiently that they are often considered to be automatic and innate. However, numerosity of non-symbolic stimuli is highly correlated with its continuous properties (e.g., density, area), and so it is hard to determine whether numerosity and continuous properties rely on the same mechanism. Here we examined the behavioral and neuronal mechanisms underlying such judgments. We scanned subjects' hemodynamic responses to a numerosity comparison task and to a surface area comparison task. In these tasks, numerical and continuous magnitudes could be either congruent or incongruent. Behaviorally, an interaction between the order of the tasks and the relevant dimension modulated the congruency effects. Continuous magnitudes always interfered with numerosity comparison. Numerosity, on the other hand, interfered with the surface area comparison only when participants began with the numerosity task. Hemodynamic activity showed that context (induced by task order) determined the neuronal pathways in which the dimensions were processed. Starting with the numerosity task led to enhanced activity in the right hemisphere, while starting with the continuous task led to enhanced left hemisphere activity. Continuous magnitudes processing relied on activation of the frontal eye field and the post-central gyrus. Processing of numerosities, on the other hand, relied on deactivation of these areas, suggesting active suppression of the continuous dimension. Accordingly, we suggest that numerosities, even in the subitizing range, are not always processed automatically; their processing depends on context and task demands. PMID:26297625

Using Dual-Task Methodology to Dissociate Automatic from Nonautomatic Processes Involved in Artificial Grammar Learning

ERIC Educational Resources Information Center

Hendricks, Michelle A.; Conway, Christopher M.; Kellogg, Ronald T.

2013-01-01

Previous studies have suggested that both automatic and intentional processes contribute to the learning of grammar and fragment knowledge in artificial grammar learning (AGL) tasks. To explore the relative contribution of automatic and intentional processes to knowledge gained in AGL, we utilized dual-task methodology to dissociate automatic and…

Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

PubMed Central

McClelland, Megan M.; Cameron, Claire E.; Duncan, Robert; Bowles, Ryan P.; Acock, Alan C.; Miao, Alicia; Pratt, Megan E.

2014-01-01

Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics. PMID:25071619

DEVELOPMENT OF AN IMPROVED SIMULATOR FOR CHEMICAL AND MICROBIAL IOR METHODS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary A. Pope; Kamy Sepehrnoori; Mojdeh Delshad

2001-10-01

This is the final report of a three-year research project on further development of a chemical and microbial improved oil recovery reservoir simulator. The objective of this research was to extend the capability of an existing simulator (UTCHEM) to improved oil recovery methods which use surfactants, polymers, gels, alkaline chemicals, microorganisms and foam as well as various combinations of these in both conventional and naturally fractured oil reservoirs. The first task was the addition of a dual-porosity model for chemical IOR in naturally fractured oil reservoirs. They formulated and implemented a multiphase, multicomponent dual porosity model for enhanced oil recoverymore » from naturally fractured reservoirs. The multiphase dual porosity model was tested against analytical solutions, coreflood data, and commercial simulators. The second task was the addition of a foam model. They implemented a semi-empirical surfactant/foam model in UTCHEM and validated the foam model by comparison with published laboratory data. The third task addressed several numerical and coding enhancements that will greatly improve its versatility and performance. Major enhancements were made in UTCHEM output files and memory management. A graphical user interface to set up the simulation input and to process the output data on a Windows PC was developed. New solvers for solving the pressure equation and geochemical system of equations were implemented and tested. A corner point grid geometry option for gridding complex reservoirs was implemented and tested. Enhancements of physical property models for both chemical and microbial IOR simulations were included in the final task of this proposal. Additional options for calculating the physical properties such as relative permeability and capillary pressure were added. A microbiological population model was developed and incorporated into UTCHEM. They have applied the model to microbial enhanced oil recovery (MEOR) processes by including the capability of permeability reduction due to biomass growth and retention. The formations of bio-products such as surfactant and polymer surfactant have also been incorporated.« less

Improved Cognition While Cycling in Parkinson’s Disease Patients and Healthy Adults

PubMed Central

Hazamy, Audrey A.; Altmann, Lori J. P.; Stegemöller, Elizabeth; Bowers, Dawn; Lee, Hyo Keun; Wilson, Jonathan; Okun, Michael S.; Hass, Chris J.

2017-01-01

Persons with Parkinson’s disease (PD) are typically more susceptible than healthy adults to impaired performance when two tasks (dual task interference) are performed simultaneously. This limitation has by many experts been attributed to limitations in cognitive resources. Nearly all studies of dual task performance in PD employ walking or balance-based motor tasks, which are commonly impaired in PD. These tasks can be performed using a combination of one or two executive function tasks. The current study examined whether persons with PD would demonstrate greater dual task effects on cognition compared to healthy older adults (HOAs) during a concurrent cycling task. Participants with and without PD completed a battery of 12 cognitive tasks assessing visual and verbal processing in the following cognitive domains: speed of processing, controlled processing, working memory and executive function. Persons with PD exhibited impairments compared to healthy participants in select tasks (i.e., 0-Back, 2-Back and operation span). Further, both groups unexpectedly exhibited dual task facilitation of response times in visual tasks across cognitive domains, and improved verbal recall during an executive function task. Only one measure, 2-back, showed a speed-accuracy trade-off in the dual task. These results demonstrate that, when paired with a motor task in which they are not impaired, people with PD exhibit similar dual task effects on cognitive tasks as HOAs, even when these dual task effects are facilitative. More generally, these findings demonstrate that pairing cognitive tasks with cycling may actually improve cognitive performance which may have therapeutic relevance to cognitive decline associated with aging and PD pathology. PMID:28088064

Relative association of processing speed, short-term memory and sustained attention with task on gait speed: a study of community-dwelling people 50 years and older.

PubMed

Killane, Isabelle; Donoghue, Orna A; Savva, George M; Cronin, Hilary; Kenny, Rose Anne; Reilly, Richard B

2014-11-01

For single gait tasks, associations have been reported between gait speed and cognitive domains. However, few studies have evaluated if this association is altered in dual gait tasks given gait speed changes with complexity and nature of task. We evaluated relative contributions of specific elements of cognitive function (including sustained attention and processing speed) to dual task gait speed in a nationally representative population of community-dwelling adults over 50 years. Gait speed was obtained using the GaitRite walkway during three gait tasks: single, cognitive (alternate letters), and motor (carrying a filled glass). Linear regression models, adjusted for covariates, were constructed to predict the relative contributions of seven neuropsychological tests to gait speed differences and to investigate gait task effects. The mean age and gait speed of the population (n = 4,431, 55% women) was 62.4 years (SD = 8.2) and 135.85 cm/s (SD = 20.20, single task), respectively. Poorer processing speed, short-term memory, and sustained attention were major cognitive contributors to slower gait speed for all gait tasks. Both dual gait tasks were robust to covariate adjustment and had a significant additional executive function element not found for the single gait task. For community-dwelling older adults processing speed, short-term memory and sustained attention were independently associated with gait speed for all gait tasks. Dual gait tasks were found to highlight specific executive function elements. This result forms a baseline value for dual task gait speed. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Face puzzle—two new video-based tasks for measuring explicit and implicit aspects of facial emotion recognition

PubMed Central

Kliemann, Dorit; Rosenblau, Gabriela; Bölte, Sven; Heekeren, Hauke R.; Dziobek, Isabel

2013-01-01

Recognizing others' emotional states is crucial for effective social interaction. While most facial emotion recognition tasks use explicit prompts that trigger consciously controlled processing, emotional faces are almost exclusively processed implicitly in real life. Recent attempts in social cognition suggest a dual process perspective, whereby explicit and implicit processes largely operate independently. However, due to differences in methodology the direct comparison of implicit and explicit social cognition has remained a challenge. Here, we introduce a new tool to comparably measure implicit and explicit processing aspects comprising basic and complex emotions in facial expressions. We developed two video-based tasks with similar answer formats to assess performance in respective facial emotion recognition processes: Face Puzzle, implicit and explicit. To assess the tasks' sensitivity to atypical social cognition and to infer interrelationship patterns between explicit and implicit processes in typical and atypical development, we included healthy adults (NT, n = 24) and adults with autism spectrum disorder (ASD, n = 24). Item analyses yielded good reliability of the new tasks. Group-specific results indicated sensitivity to subtle social impairments in high-functioning ASD. Correlation analyses with established implicit and explicit socio-cognitive measures were further in favor of the tasks' external validity. Between group comparisons provide first hints of differential relations between implicit and explicit aspects of facial emotion recognition processes in healthy compared to ASD participants. In addition, an increased magnitude of between group differences in the implicit task was found for a speed-accuracy composite measure. The new Face Puzzle tool thus provides two new tasks to separately assess explicit and implicit social functioning, for instance, to measure subtle impairments as well as potential improvements due to social cognitive interventions. PMID:23805122

The puzzle of processing speed, memory, and executive function impairments in schizophrenia: fitting the pieces together.

PubMed

Knowles, Emma E M; Weiser, Mark; David, Anthony S; Glahn, David C; Davidson, Michael; Reichenberg, Abraham

2015-12-01

Substantial impairment in performance on the digit-symbol substitution task in patients with schizophrenia is well established, which has been widely interpreted as denoting a specific impairment in processing speed. However, other higher order cognitive functions might be more critical to performance on this task. To date, this idea has not been rigorously investigated in patients with schizophrenia. Neuropsychological measures of processing speed, memory, and executive functioning were completed by 125 patients with schizophrenia and 272 control subjects. We implemented a series of confirmatory factor and structural regression modeling to build an integrated model of processing speed, memory, and executive function with which to deconstruct the digit-symbol substitution task and characterize discrepancies between patients with schizophrenia and control subjects. The overall structure of the processing speed, memory, and executive function model was the same across groups (χ(2) = 208.86, p > .05), but the contribution of the specific cognitive domains to coding task performance differed significantly. When completing the task, control subjects relied on executive function and, indirectly, on working memory ability, whereas patients with schizophrenia used an alternative set of cognitive operations whereby they relied on the same processes required to complete verbal fluency tasks. Successful coding task performance relies predominantly on executive function, rather than processing speed or memory. Patients with schizophrenia perform poorly on this task because of an apparent lack of appropriate executive function input; they rely instead on an alternative cognitive pathway. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Distinct Effects of Trial-Driven and Task Set-Related Control in Primary Visual Cortex

PubMed Central

Vaden, Ryan J.; Visscher, Kristina M.

2015-01-01

Task sets are task-specific configurations of cognitive processes that facilitate task-appropriate reactions to stimuli. While it is established that the trial-by-trial deployment of visual attention to expected stimuli influences neural responses in primary visual cortex (V1) in a retinotopically specific manner, it is not clear whether the mechanisms that help maintain a task set over many trials also operate with similar retinotopic specificity. Here, we address this question by using BOLD fMRI to characterize how portions of V1 that are specialized for different eccentricities respond during distinct components of an attention-demanding discrimination task: cue-driven preparation for a trial, trial-driven processing, task-initiation at the beginning of a block of trials, and task-maintenance throughout a block of trials. Tasks required either unimodal attention to an auditory or a visual stimulus or selective intermodal attention to the visual or auditory component of simultaneously presented visual and auditory stimuli. We found that while the retinotopic patterns of trial-driven and cue-driven activity depended on the attended stimulus, the retinotopic patterns of task-initiation and task-maintenance activity did not. Further, only the retinotopic patterns of trial-driven activity were found to depend on the presence of intermodal distraction. Participants who performed well on the intermodal selective attention tasks showed strong task-specific modulations of both trial-driven and task-maintenance activity. Importantly, task-related modulations of trial-driven and task-maintenance activity were in opposite directions. Together, these results confirm that there are (at least) two different processes for top-down control of V1: One, working trial-by-trial, differently modulates activity across different eccentricity sectors—portions of V1 corresponding to different visual eccentricities. The second process works across longer epochs of task performance, and does not differ among eccentricity sectors. These results are discussed in the context of previous literature examining top-down control of visual cortical areas. PMID:26163806

Transfer after Dual n-Back Training Depends on Striatal Activation Change.

PubMed

Salminen, Tiina; Kühn, Simone; Frensch, Peter A; Schubert, Torsten

2016-09-28

The dual n-back working memory (WM) training paradigm (comprising auditory and visual stimuli) has gained much attention since studies have shown widespread transfer effects. By including a multimodal dual-task component, the task is demanding to the human cognitive system. We investigated whether dual n-back training improves general cognitive resources or a task-specific WM updating process in participants. We expected: (1) widespread transfer effects and the recruitment of a common neuronal network by the training and the transfer tasks and (2) narrower transfer results and that a common activation network alone would not produce transfer, but instead an activation focus on the striatum, which is associated with WM updating processes. The training group showed transfer to an untrained dual-modality WM updating task, but not to single-task versions of the training or the transfer task. They also showed diminished neuronal overlap between the training and the transfer task from pretest to posttest and an increase in striatal activation in both tasks. Furthermore, we found an association between the striatal activation increase and behavioral improvement. The control groups showed no transfer and no change in the amount of activation overlap or in striatal activation from pretest to posttest. We conclude that, instead of improving general cognitive resources (which would have required a transfer effect to all transfer tasks and that a frontal activation overlap between the tasks produced transfer), dual n-back training improved a task-specific process: WM updating of stimuli from two modalities. The current study allows for a better understanding of the cognitive and neural effects of working memory (WM) training and transfer. It shows that dual n-back training mainly improves specific processes of WM updating, and this improvement leads to narrow transfer effects to tasks involving the same processes. On a neuronal level this is accompanied by increased neural activation in the striatum that is related to WM updating. The current findings challenge the view that dual n-back training provokes a general boosting of the WM system and of its neural underpinnings located in frontoparietal brain regions. Instead, the findings imply the relevance of task-specific brain regions which are involved in important cognitive processes during training and transfer tasks. Copyright © 2016 the authors 0270-6474/16/3610198-16$15.00/0.

Perceptual learning: toward a comprehensive theory.

PubMed

Watanabe, Takeo; Sasaki, Yuka

2015-01-03

Visual perceptual learning (VPL) is long-term performance increase resulting from visual perceptual experience. Task-relevant VPL of a feature results from training of a task on the feature relevant to the task. Task-irrelevant VPL arises as a result of exposure to the feature irrelevant to the trained task. At least two serious problems exist. First, there is the controversy over which stage of information processing is changed in association with task-relevant VPL. Second, no model has ever explained both task-relevant and task-irrelevant VPL. Here we propose a dual plasticity model in which feature-based plasticity is a change in a representation of the learned feature, and task-based plasticity is a change in processing of the trained task. Although the two types of plasticity underlie task-relevant VPL, only feature-based plasticity underlies task-irrelevant VPL. This model provides a new comprehensive framework in which apparently contradictory results could be explained.

Sleep deprivation influences some but not all processes of supervisory attention

NASA Technical Reports Server (NTRS)

Jennings, J. R.; Monk, T. H.; van der Molen, M. W.

2003-01-01

Does one night of sleep deprivation alter processes of supervisory attention in general or only a specific subset of such processes? Twenty college-aged volunteers, half female, performed a choice reaction time task. A cue indicated that compatible (e.g., right button, right-pointing arrow) or incompatible (e.g., left button, right-pointing arrow) responses were to be given to a stimulus that followed 50 or 500 ms later. The paradigm assessed response inhibition, task-shifting skill, and task strategy-processes inherent in supervisory attention. Performance, along with heart rate, was assessed for 12 hr following normal sleep or a night of complete sleep deprivation. Sleep deprivation altered neither preparation for task shifting nor response inhibition. The ability to use preparatory bias to speed performance did decrease with sleep deprivation. Sleep deprivation appears to selectively affect this supervisory attention process, which is perceived as an active effort to cope with a challenging task.

Sleep deprivation influences some but not all processes of supervisory attention.

PubMed

Jennings, J R; Monk, T H; van der Molen, M W

2003-09-01

Does one night of sleep deprivation alter processes of supervisory attention in general or only a specific subset of such processes? Twenty college-aged volunteers, half female, performed a choice reaction time task. A cue indicated that compatible (e.g., right button, right-pointing arrow) or incompatible (e.g., left button, right-pointing arrow) responses were to be given to a stimulus that followed 50 or 500 ms later. The paradigm assessed response inhibition, task-shifting skill, and task strategy-processes inherent in supervisory attention. Performance, along with heart rate, was assessed for 12 hr following normal sleep or a night of complete sleep deprivation. Sleep deprivation altered neither preparation for task shifting nor response inhibition. The ability to use preparatory bias to speed performance did decrease with sleep deprivation. Sleep deprivation appears to selectively affect this supervisory attention process, which is perceived as an active effort to cope with a challenging task.

Increasing Working Memory Load Reduces Processing of Cross-Modal Task-Irrelevant Stimuli Even after Controlling for Task Difficulty and Executive Capacity

PubMed Central

Simon, Sharon S.; Tusch, Erich S.; Holcomb, Phillip J.; Daffner, Kirk R.

2016-01-01

The classic account of the load theory (LT) of attention suggests that increasing cognitive load leads to greater processing of task-irrelevant stimuli due to competition for limited executive resource that reduces the ability to actively maintain current processing priorities. Studies testing this hypothesis have yielded widely divergent outcomes. The inconsistent results may, in part, be related to variability in executive capacity (EC) and task difficulty across subjects in different studies. Here, we used a cross-modal paradigm to investigate whether augmented working memory (WM) load leads to increased early distracter processing, and controlled for the potential confounders of EC and task difficulty. Twenty-three young subjects were engaged in a primary visual WM task, under high and low load conditions, while instructed to ignore irrelevant auditory stimuli. Demands of the high load condition were individually titrated to make task difficulty comparable across subjects with differing EC. Event-related potentials (ERPs) were used to measure neural activity in response to stimuli presented in both the task relevant modality (visual) and task-irrelevant modality (auditory). Behavioral results indicate that the load manipulation and titration procedure of the primary visual task were successful. ERPs demonstrated that in response to visual target stimuli, there was a load-related increase in the posterior slow wave, an index of sustained attention and effort. Importantly, under high load, there was a decrease of the auditory N1 in response to distracters, a marker of early auditory processing. These results suggest that increased WM load is associated with enhanced attentional engagement and protection from distraction in a cross-modal setting, even after controlling for task difficulty and EC. Our findings challenge the classic LT and offer support for alternative models. PMID:27536226

Increasing Working Memory Load Reduces Processing of Cross-Modal Task-Irrelevant Stimuli Even after Controlling for Task Difficulty and Executive Capacity.

PubMed

Simon, Sharon S; Tusch, Erich S; Holcomb, Phillip J; Daffner, Kirk R

2016-01-01

The classic account of the load theory (LT) of attention suggests that increasing cognitive load leads to greater processing of task-irrelevant stimuli due to competition for limited executive resource that reduces the ability to actively maintain current processing priorities. Studies testing this hypothesis have yielded widely divergent outcomes. The inconsistent results may, in part, be related to variability in executive capacity (EC) and task difficulty across subjects in different studies. Here, we used a cross-modal paradigm to investigate whether augmented working memory (WM) load leads to increased early distracter processing, and controlled for the potential confounders of EC and task difficulty. Twenty-three young subjects were engaged in a primary visual WM task, under high and low load conditions, while instructed to ignore irrelevant auditory stimuli. Demands of the high load condition were individually titrated to make task difficulty comparable across subjects with differing EC. Event-related potentials (ERPs) were used to measure neural activity in response to stimuli presented in both the task relevant modality (visual) and task-irrelevant modality (auditory). Behavioral results indicate that the load manipulation and titration procedure of the primary visual task were successful. ERPs demonstrated that in response to visual target stimuli, there was a load-related increase in the posterior slow wave, an index of sustained attention and effort. Importantly, under high load, there was a decrease of the auditory N1 in response to distracters, a marker of early auditory processing. These results suggest that increased WM load is associated with enhanced attentional engagement and protection from distraction in a cross-modal setting, even after controlling for task difficulty and EC. Our findings challenge the classic LT and offer support for alternative models.

After-shift Musculoskeletal Disorder Symptoms in Female Workers and Work-related Factors: A Cross-sectional Study in a Seafood Processing Factory in Vietnam.

PubMed

Tran, Thuy Thi Thu; Phan, Chinh Thi Thuy; Pham, Tuan Cong; Nguyen, Quynh Thuy

2016-01-01

The seafood processing industry has been developing and providing marked contribution to Vietnam's economic growth in recent years. However, information on working conditions and their impacts to workers' health in this sector, focusing on musculoskeletal problems in female workers, has been poorly documented. This paper examines the prevalence of after-shift musculoskeletal disorder symptoms (A-MSDS) and work-related factors in female workers in a seafood processing factory in Vietnam. As part of a comprehensive study, a cross-sectional survey was implemented in one seafood processing factory in the center of Vietnam in 2014. A self-administered questionnaire was completed by 394 female workers to collect information about their A-MSDS state, demographic characteristics, health status and work conditions. Descriptive analysis and logistic regression were applied to describe and analyse the results. Nearly four-fifths of female workers experienced MSDs in at least one body part (77.7%) and 20.1% of them had MSDs in all investigated regions. The prevalence of A-MSDS in different body parts markedly varied, with the proportion of pain in the hips and lower extremities being as high as 53.3%, followed by pain in the shoulders and upper extremities (42.6%) and the neck (41.1%). A humid working environment, exposure to vibration and chemicals as well as taxing task demands and work organizations were found to significantly contribute to the increased risk of after-shift musculoskeletal disorders in female workers. Approximately 80% of female workers in the seafood processing factory experienced musculoskeletal pains after work, especially in the hips, extremities, neck and shoulders which were contributed by work conditions and task demands.

After-shift Musculoskeletal Disorder Symptoms in Female Workers and Work-related Factors: A Cross-sectional Study in a Seafood Processing Factory in Vietnam

PubMed Central

Tran, Thuy Thi Thu; Phan, Chinh Thi Thuy; Pham, Tuan Cong; Nguyen, Quynh Thuy

2016-01-01

Background The seafood processing industry has been developing and providing marked contribution to Vietnam's economic growth in recent years. However, information on working conditions and their impacts to workers' health in this sector, focusing on musculoskeletal problems in female workers, has been poorly documented. Objectives This paper examines the prevalence of after-shift musculoskeletal disorder symptoms (A-MSDS) and work-related factors in female workers in a seafood processing factory in Vietnam. Materials and Methods As part of a comprehensive study, a cross-sectional survey was implemented in one seafood processing factory in the center of Vietnam in 2014. A self-administered questionnaire was completed by 394 female workers to collect information about their A-MSDS state, demographic characteristics, health status and work conditions. Descriptive analysis and logistic regression were applied to describe and analyse the results. Results Nearly four-fifths of female workers experienced MSDs in at least one body part (77.7%) and 20.1% of them had MSDs in all investigated regions. The prevalence of A-MSDS in different body parts markedly varied, with the proportion of pain in the hips and lower extremities being as high as 53.3%, followed by pain in the shoulders and upper extremities (42.6%) and the neck (41.1%). A humid working environment, exposure to vibration and chemicals as well as taxing task demands and work organizations were found to significantly contribute to the increased risk of after-shift musculoskeletal disorders in female workers. Conclusion Approximately 80% of female workers in the seafood processing factory experienced musculoskeletal pains after work, especially in the hips, extremities, neck and shoulders which were contributed by work conditions and task demands. PMID:29546192

Internet Usage, User Satisfaction, Task-Technology Fit, and Performance Impact among Public Sector Employees in Yemen

ERIC Educational Resources Information Center

Isaac, Osama; Abdullah, Zaini; Ramayah, T.; Mutahar, Ahmed M.

2017-01-01

Purpose: The internet technology becomes an essential tool for individuals, organizations, and nations for growth and prosperity. The purpose of this paper is to integrate the DeLone and McLean IS success model with task-technology fit (TTF) to explain the performance impact of Yemeni Government employees. Design/methodology/approach:…

Partners in Economic Growth: High Technology Industry and Postsecondary Education. The Report of the Task Force on High Technology.

ERIC Educational Resources Information Center

Saskatchewan Dept. of Advanced Education and Manpower, Saskatoon.

An analysis is presented of the adequacy of Saskatchewan's technical institutes to satisfy the skilled labor needs of the emergent high technology industry. After section 1 summarizes the recommendations of the Task Force appointed to study the issue, section 2 offers a definition of "high technology" industries, looks at the effects of…

Do Errors on Classroom Reading Tasks Slow Growth in Reading? Technical Report No. 404.

ERIC Educational Resources Information Center

Anderson, Richard C.; And Others

A pervasive finding from research on teaching and classroom learning is that a low rate of error on classroom tasks is associated with large year to year gains in achievement, particularly for reading in the primary grades. The finding of a negative relationship between error rate, especially rate of oral reading errors, and gains in reading…

Midwives Performance in Early Detection of Growth and Development Irregularities of Children Based on Task Commitment

ERIC Educational Resources Information Center

Utami, Sri; Nursalam; Hargono, Rachmat; Susilaningrum, Rekawati

2016-01-01

The purpose of this study was to analyze the performance of midwives based on the task commitment. This was an observational analytic with cross sectional approach. Multistage random sampling was used to determine the public health center, proportional random sampling to selected participants. The samples were 222 midwives in the public health…

Memory systems, processes, and tasks: taxonomic clarification via factor analysis.

PubMed

Bruss, Peter J; Mitchell, David B

2009-01-01

The nature of various memory systems was examined using factor analysis. We reanalyzed data from 11 memory tasks previously reported in Mitchell and Bruss (2003). Four well-defined factors emerged, closely resembling episodic and semantic memory and conceptual and perceptual implicit memory, in line with both memory systems and transfer-appropriate processing accounts. To explore taxonomic issues, we ran separate analyses on the implicit tasks. Using a cross-format manipulation (pictures vs. words), we identified 3 prototypical tasks. Word fragment completion and picture fragment identification tasks were "factor pure," tapping perceptual processes uniquely. Category exemplar generation revealed its conceptual nature, yielding both cross-format priming and a picture superiority effect. In contrast, word stem completion and picture naming were more complex, revealing attributes of both processes.

Maximizing Total QoS-Provisioning of Image Streams with Limited Energy Budget

NASA Astrophysics Data System (ADS)

Lee, Wan Yeon; Kim, Kyong Hoon; Ko, Young Woong

To fully utilize the limited battery energy of mobile electronic devices, we propose an adaptive adjustment method of processing quality for multiple image stream tasks running with widely varying execution times. This adjustment method completes the worst-case executions of the tasks with a given budget of energy, and maximizes the total reward value of processing quality obtained during their executions by exploiting the probability distribution of task execution times. The proposed method derives the maximum reward value for the tasks being executable with arbitrary processing quality, and near maximum value for the tasks being executable with a finite number of processing qualities. Our evaluation on a prototype system shows that the proposed method achieves larger reward values, by up to 57%, than the previous method.

Task modulated brain connectivity of the amygdala: a meta-analysis of psychophysiological interactions.

PubMed

Di, Xin; Huang, Jia; Biswal, Bharat B

2017-01-01

Understanding functional connectivity of the amygdala with other brain regions, especially task modulated connectivity, is a critical step toward understanding the role of the amygdala in emotional processes and the interactions between emotion and cognition. The present study performed coordinate-based meta-analysis on studies of task modulated connectivity of the amygdala which used psychophysiological interaction (PPI) analysis. We first analyzed 49 PPI studies on different types of tasks using activation likelihood estimation (ALE) meta-analysis. Widespread cortical and subcortical regions showed consistent task modulated connectivity with the amygdala, including the medial frontal cortex, bilateral insula, anterior cingulate, fusiform gyrus, parahippocampal gyrus, thalamus, and basal ganglia. These regions were in general overlapped with those showed coactivations with the amygdala, suggesting that these regions and amygdala are not only activated together, but also show different levels of interactions during tasks. Further analyses with subsets of PPI studies revealed task specific functional connectivities with the amygdala that were modulated by fear processing, face processing, and emotion regulation. These results suggest a dynamic modulation of connectivity upon task demands, and provide new insights on the functions of the amygdala in different affective and cognitive processes. The meta-analytic approach on PPI studies may offer a framework toward systematical examinations of task modulated connectivity.

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence.

PubMed

Reimer, Christina B; Strobach, Tilo; Schubert, Torsten

2017-12-01

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.

Effects of Age, Task Performance, and Structural Brain Development on Face Processing

PubMed Central

Cohen Kadosh, Kathrin; Johnson, Mark H; Dick, Frederic; Cohen Kadosh, Roi; Blakemore, Sarah-Jayne

2013-01-01

In this combined structural and functional MRI developmental study, we tested 48 participants aged 7–37 years on 3 simple face-processing tasks (identity, expression, and gaze task), which were designed to yield very similar performance levels across the entire age range. The same participants then carried out 3 more difficult out-of-scanner tasks, which provided in-depth measures of changes in performance. For our analysis we adopted a novel, systematic approach that allowed us to differentiate age- from performance-related changes in the BOLD response in the 3 tasks, and compared these effects to concomitant changes in brain structure. The processing of all face aspects activated the core face-network across the age range, as well as additional and partially separable regions. Small task-specific activations in posterior regions were found to increase with age and were distinct from more widespread activations that varied as a function of individual task performance (but not of age). Our results demonstrate that activity during face-processing changes with age, and these effects are still observed when controlling for changes associated with differences in task performance. Moreover, we found that changes in white and gray matter volume were associated with changes in activation with age and performance in the out-of-scanner tasks. PMID:22661406

New Technology Industries. Skills Task Force Research Paper 10.

ERIC Educational Resources Information Center

Hendry, Chris

This paper provides an overview of the growth of new technology industries in Great Britain and the skills needed for these industries. The industries are advanced materials, biotechnology, and opto-electronics. The report profiles the current status, expected growth, and skills needed for each of these industry sectors. It also points out the…

The Implications of Psychosocial Theory for Personal Growth in the Family.

ERIC Educational Resources Information Center

Newman, Philip R.; Newman, Barbara M.

Psychosocial theory, based on the ideas of Erik Erikson and Robert Havighurst, is proposed as a useful framework for conceptualizing the potential for growth within the family. Erikson's (1950) eight stage theory of psychosocial development and Havighurst's (1959) concept of developmental tasks are used to take account of the stages of development…

Knowledge Growth and Maintenance across the Lifespan: The Role of Print Exposure.

ERIC Educational Resources Information Center

Stanowich, Keith E.; And Others

1995-01-01

Examined the effects of print exposure on growth of declarative knowledge and vocabulary in 133 college students and 49 elderly adults. Compared groups on two general knowledge tasks, vocabulary, working memory, syllogistic reasoning, and print exposure. Found that exposure to print was a significant predictor of declarative and vocabulary…

Contextual and perceptual brain processes underlying moral cognition: a quantitative meta-analysis of moral reasoning and moral emotions.

PubMed

Sevinc, Gunes; Spreng, R Nathan

2014-01-01

Human morality has been investigated using a variety of tasks ranging from judgments of hypothetical dilemmas to viewing morally salient stimuli. These experiments have provided insight into neural correlates of moral judgments and emotions, yet these approaches reveal important differences in moral cognition. Moral reasoning tasks require active deliberation while moral emotion tasks involve the perception of stimuli with moral implications. We examined convergent and divergent brain activity associated with these experimental paradigms taking a quantitative meta-analytic approach. A systematic search of the literature yielded 40 studies. Studies involving explicit decisions in a moral situation were categorized as active (n = 22); studies evoking moral emotions were categorized as passive (n = 18). We conducted a coordinate-based meta-analysis using the Activation Likelihood Estimation to determine reliable patterns of brain activity. Results revealed a convergent pattern of reliable brain activity for both task categories in regions of the default network, consistent with the social and contextual information processes supported by this brain network. Active tasks revealed more reliable activity in the temporoparietal junction, angular gyrus and temporal pole. Active tasks demand deliberative reasoning and may disproportionately involve the retrieval of social knowledge from memory, mental state attribution, and construction of the context through associative processes. In contrast, passive tasks reliably engaged regions associated with visual and emotional information processing, including lingual gyrus and the amygdala. A laterality effect was observed in dorsomedial prefrontal cortex, with active tasks engaging the left, and passive tasks engaging the right. While overlapping activity patterns suggest a shared neural network for both tasks, differential activity suggests that processing of moral input is affected by task demands. The results provide novel insight into distinct features of moral cognition, including the generation of moral context through associative processes and the perceptual detection of moral salience.

Contextual and Perceptual Brain Processes Underlying Moral Cognition: A Quantitative Meta-Analysis of Moral Reasoning and Moral Emotions

PubMed Central

Sevinc, Gunes; Spreng, R. Nathan

2014-01-01

Background and Objectives Human morality has been investigated using a variety of tasks ranging from judgments of hypothetical dilemmas to viewing morally salient stimuli. These experiments have provided insight into neural correlates of moral judgments and emotions, yet these approaches reveal important differences in moral cognition. Moral reasoning tasks require active deliberation while moral emotion tasks involve the perception of stimuli with moral implications. We examined convergent and divergent brain activity associated with these experimental paradigms taking a quantitative meta-analytic approach. Data Source A systematic search of the literature yielded 40 studies. Studies involving explicit decisions in a moral situation were categorized as active (n = 22); studies evoking moral emotions were categorized as passive (n = 18). We conducted a coordinate-based meta-analysis using the Activation Likelihood Estimation to determine reliable patterns of brain activity. Results & Conclusions Results revealed a convergent pattern of reliable brain activity for both task categories in regions of the default network, consistent with the social and contextual information processes supported by this brain network. Active tasks revealed more reliable activity in the temporoparietal junction, angular gyrus and temporal pole. Active tasks demand deliberative reasoning and may disproportionately involve the retrieval of social knowledge from memory, mental state attribution, and construction of the context through associative processes. In contrast, passive tasks reliably engaged regions associated with visual and emotional information processing, including lingual gyrus and the amygdala. A laterality effect was observed in dorsomedial prefrontal cortex, with active tasks engaging the left, and passive tasks engaging the right. While overlapping activity patterns suggest a shared neural network for both tasks, differential activity suggests that processing of moral input is affected by task demands. The results provide novel insight into distinct features of moral cognition, including the generation of moral context through associative processes and the perceptual detection of moral salience. PMID:24503959

Model curriculum outline for Alternatively Fueled Vehicle (AFV) automotive technician training in light and medium duty CNG and LPG

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This model curriculum outline was developed using a turbo-DACUM (Developing a Curriculum) process which utilizes practicing experts to undertake a comprehensive job and task analysis. The job and task analysis serves to establish current baseline data accurately and to improve both the process and the product of the job through constant and continuous improvement of training. The DACUM process is based on the following assumptions: (1) Expert workers are the best source for task analysis. (2) Any occupation can be described effectively in terms of tasks. (3) All tasks imply knowledge, skills, and attitudes/values. A DACUM panel, comprised of sixmore » experienced and knowledgeable technicians who are presently working in the field, was given an orientation to the DACUM process. The panel then identified, verified, and sequenced all the necessary job duty areas and tasks. The broad duty categories were rated according to relative importance and assigned percentage ratings in priority order. The panel then rated every task for each of the duties on a scale of 1 to 3. A rating of 3 indicates an {open_quotes}essential{close_quotes} task, a rating of 2 indicates an {open_quotes}important{close_quotes} task, and a rating of 1 indicates a {open_quotes}desirable{close_quotes} task.« less

The Use of Digital Technology in Finding Multiple Paths to Solve and Extend an Equilateral Triangle Task

ERIC Educational Resources Information Center

Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

2016-01-01

Mathematical tasks are crucial elements for teachers to orient, foster and assess students' processes to comprehend and develop mathematical knowledge. During the process of working and solving a task, searching for or discussing multiple solution paths becomes a powerful strategy for students to engage in mathematical thinking. A simple task that…

Effects of task demands on the early neural processing of fearful and happy facial expressions.

PubMed

Itier, Roxane J; Neath-Tavares, Karly N

2017-05-15

Task demands shape how we process environmental stimuli but their impact on the early neural processing of facial expressions remains unclear. In a within-subject design, ERPs were recorded to the same fearful, happy and neutral facial expressions presented during a gender discrimination, an explicit emotion discrimination and an oddball detection tasks, the most studied tasks in the field. Using an eye tracker, fixation on the face nose was enforced using a gaze-contingent presentation. Task demands modulated amplitudes from 200 to 350ms at occipito-temporal sites spanning the EPN component. Amplitudes were more negative for fearful than neutral expressions starting on N170 from 150 to 350ms, with a temporo-occipital distribution, whereas no clear effect of happy expressions was seen. Task and emotion effects never interacted in any time window or for the ERP components analyzed (P1, N170, EPN). Thus, whether emotion is explicitly discriminated or irrelevant for the task at hand, neural correlates of fearful and happy facial expressions seem immune to these task demands during the first 350ms of visual processing. Copyright © 2017 Elsevier B.V. All rights reserved.

CDK5-A Novel Role in Prostate Cancer Immunotherapy

DTIC Science & Technology

2017-10-01

of the involvement of a T cell antitumor response in impaired growth of prostate cancer in immunocompetent murine models of prostate cancer, and...of immune system activation by Cdk5 deletion in prostate cancer. We will confirm the involvement of a T cell antitumor response in impaired growth of...project? Major Task 1: Involvement of T cell anticancer immune response in impaired growth of TRAMP Cdk5-/- model. Months 1-10. Completed, month 10

Semantic Neighborhood Effects for Abstract versus Concrete Words

PubMed Central

Danguecan, Ashley N.; Buchanan, Lori

2016-01-01

Studies show that semantic effects may be task-specific, and thus, that semantic representations are flexible and dynamic. Such findings are critical to the development of a comprehensive theory of semantic processing in visual word recognition, which should arguably account for how semantic effects may vary by task. It has been suggested that semantic effects are more directly examined using tasks that explicitly require meaning processing relative to those for which meaning processing is not necessary (e.g., lexical decision task). The purpose of the present study was to chart the processing of concrete versus abstract words in the context of a global co-occurrence variable, semantic neighborhood density (SND), by comparing word recognition response times (RTs) across four tasks varying in explicit semantic demands: standard lexical decision task (with non-pronounceable non-words), go/no-go lexical decision task (with pronounceable non-words), progressive demasking task, and sentence relatedness task. The same experimental stimulus set was used across experiments and consisted of 44 concrete and 44 abstract words, with half of these being low SND, and half being high SND. In this way, concreteness and SND were manipulated in a factorial design using a number of visual word recognition tasks. A consistent RT pattern emerged across tasks, in which SND effects were found for abstract (but not necessarily concrete) words. Ultimately, these findings highlight the importance of studying interactive effects in word recognition, and suggest that linguistic associative information is particularly important for abstract words. PMID:27458422

Semantic Neighborhood Effects for Abstract versus Concrete Words.

PubMed

Danguecan, Ashley N; Buchanan, Lori

2016-01-01

Studies show that semantic effects may be task-specific, and thus, that semantic representations are flexible and dynamic. Such findings are critical to the development of a comprehensive theory of semantic processing in visual word recognition, which should arguably account for how semantic effects may vary by task. It has been suggested that semantic effects are more directly examined using tasks that explicitly require meaning processing relative to those for which meaning processing is not necessary (e.g., lexical decision task). The purpose of the present study was to chart the processing of concrete versus abstract words in the context of a global co-occurrence variable, semantic neighborhood density (SND), by comparing word recognition response times (RTs) across four tasks varying in explicit semantic demands: standard lexical decision task (with non-pronounceable non-words), go/no-go lexical decision task (with pronounceable non-words), progressive demasking task, and sentence relatedness task. The same experimental stimulus set was used across experiments and consisted of 44 concrete and 44 abstract words, with half of these being low SND, and half being high SND. In this way, concreteness and SND were manipulated in a factorial design using a number of visual word recognition tasks. A consistent RT pattern emerged across tasks, in which SND effects were found for abstract (but not necessarily concrete) words. Ultimately, these findings highlight the importance of studying interactive effects in word recognition, and suggest that linguistic associative information is particularly important for abstract words.

Language mapping with verbs and sentences in awake surgery: a review.

PubMed

Rofes, Adrià; Miceli, Gabriele

2014-06-01

Intraoperative language mapping in awake surgery is typically conducted by asking the patient to produce automatic speech and to name objects. These tasks might not map language with sufficient accuracy, as some linguistic processes can only be triggered by tasks that use verbs and sentences. Verb and sentence processing tasks are currently used during surgery, albeit sparsely. Medline, PubMed, and Web of Science records were searched to retrieve studies focused on language mapping with verbs/sentences in awake surgery. We review the tasks reported in the published literature, spell out the language processes assessed by each task, list the cortical and subcortical regions whose stimulation inhibited language processing, and consider the types of errors elicited by stimulation in each region. We argue that using verb tasks allows a more thorough evaluation of language functions. We also argue that verb tasks are preferable to object naming tasks in the case of frontal lesions, as lesion and neuroimaging data demonstrate that these regions play a critical role in verb and sentence processing. We discuss the clinical value of these tasks and the current limitations of the procedure, and provide some guidelines for their development. Future research should aim toward a differentiated approach to language mapping - one that includes the administration of standardized and customizable tests and the use of longitudinal neurocognitive follow-up studies. Further work will allow researchers and clinicians to understand brain and language correlates and to improve the current surgical practice.

Memory functions of children born with asymmetric intrauterine growth restriction.

PubMed

Geva, Ronny; Eshel, Rina; Leitner, Yael; Fattal-Valevski, Aviva; Harel, Shaul

2006-10-30

Learning difficulties are frequently diagnosed in children born with intrauterine growth restriction (IUGR). Models of various animal species with IUGR were studied and demonstrated specific susceptibility and alterations of the hippocampal formation and its related neural structures. The main purpose was to study memory functions of children born with asymmetric IUGR in a large-scale cohort using a long-term prospective paradigm. One hundred and ten infants diagnosed with IUGR were followed-up from birth to 9 years of age. Their performance was compared with a group of 63 children with comparable gestational age and multiple socioeconomic factors. Memory functions (short-term, super- and long-term spans) for different stimuli types (verbal and visual) were evaluated using Visual Auditory Digit Span tasks (VADS), Rey Auditory Verbal Learning Test (Rey-AVLT), and Rey Osterrieth Complex Figure Test (ROCF). Children with IUGR had short-term memory difficulties that hindered both serial verbal processing system and simultaneous processing of high-load visuo-spatial stimuli. The difficulties were not related to prematurity, neonatal complications or growth catch-up, but were augmented by lower maternal education. Recognition skills and benefits from reiteration, typically affected by hippocampal dysfunction, were preserved in both groups. Memory profile of children born with IUGR is characterized primarily by a short-term memory deficit that does not necessarily comply with a typical hippocampal deficit, but rather may reflect an executive short-term memory deficit characteristic of anterior hippocampal-prefrontal network. Implications for cognitive intervention are discussed.

The dynamic relationship between plant architecture and competition

PubMed Central

Ford, E. David

2014-01-01

In this review, structural and functional changes are described in single-species, even-aged, stands undergoing competition for light. Theories of the competition process as interactions between whole plants have been advanced but have not been successful in explaining these changes and how they vary between species or growing conditions. This task now falls to researchers in plant architecture. Research in plant architecture has defined three important functions of individual plants that determine the process of canopy development and competition: (i) resource acquisition plasticity; (ii) morphogenetic plasticity; (iii) architectural variation in efficiency of interception and utilization of light. In this review, this research is synthesized into a theory for competition based on five groups of postulates about the functioning of plants in stands. Group 1: competition for light takes place at the level of component foliage and branches. Group 2: the outcome of competition is determined by the dynamic interaction between processes that exert dominance and processes that react to suppression. Group 3: species differences may affect both exertion of dominance and reaction to suppression. Group 4: individual plants may simultaneously exhibit, in different component parts, resource acquisition and morphogenetic plasticity. Group 5: mortality is a time-delayed response to suppression. Development of architectural models when combined with field investigations is identifying research needed to develop a theory of architectural influences on the competition process. These include analyses of the integration of foliage and branch components into whole-plant growth and precise definitions of environmental control of morphogenetic plasticity and its interaction with acquisition of carbon for plant growth. PMID:24987396

The dynamic relationship between plant architecture and competition.

PubMed

Ford, E David

2014-01-01

In this review, structural and functional changes are described in single-species, even-aged, stands undergoing competition for light. Theories of the competition process as interactions between whole plants have been advanced but have not been successful in explaining these changes and how they vary between species or growing conditions. This task now falls to researchers in plant architecture. Research in plant architecture has defined three important functions of individual plants that determine the process of canopy development and competition: (i) resource acquisition plasticity; (ii) morphogenetic plasticity; (iii) architectural variation in efficiency of interception and utilization of light. In this review, this research is synthesized into a theory for competition based on five groups of postulates about the functioning of plants in stands. Group 1: competition for light takes place at the level of component foliage and branches. Group 2: the outcome of competition is determined by the dynamic interaction between processes that exert dominance and processes that react to suppression. Group 3: species differences may affect both exertion of dominance and reaction to suppression. Group 4: individual plants may simultaneously exhibit, in different component parts, resource acquisition and morphogenetic plasticity. Group 5: mortality is a time-delayed response to suppression. Development of architectural models when combined with field investigations is identifying research needed to develop a theory of architectural influences on the competition process. These include analyses of the integration of foliage and branch components into whole-plant growth and precise definitions of environmental control of morphogenetic plasticity and its interaction with acquisition of carbon for plant growth.

Learning to multitask: effects of video game practice on electrophysiological indices of attention and resource allocation.

PubMed

Maclin, Edward L; Mathewson, Kyle E; Low, Kathy A; Boot, Walter R; Kramer, Arthur F; Fabiani, Monica; Gratton, Gabriele

2011-09-01

Changes in attention allocation with complex task learning reflect processing automatization and more efficient control. We studied these changes using ERP and EEG spectral analyses in subjects playing Space Fortress, a complex video game comprising standard cognitive task components. We hypothesized that training would free up attentional resources for a secondary auditory oddball task. Both P3 and delta EEG showed a processing trade-off between game and oddball tasks, but only some game events showed reduced attention requirements with practice. Training magnified a transient increase in alpha power following both primary and secondary task events. This contrasted with alpha suppression observed when the oddball task was performed alone, suggesting that alpha may be related to attention switching. Hence, P3 and EEG spectral data are differentially sensitive to changes in attentional processing occurring with complex task training. Copyright © 2011 Society for Psychophysiological Research.

MOCVD process technology for affordable, high-yield, high-performance MESFET structures. Phase 3: MIMIC

NASA Astrophysics Data System (ADS)

1993-01-01

Under the MIMIC Program, Spire has pursued improvements in the manufacturing of low cost, high quality gallium arsenide MOCVD wafers for advanced MIMIC FET applications. As a demonstration of such improvements, Spire was tasked to supply MOCVD wafers for comparison to MBE wafers in the fabrication of millimeter and microwave integrated circuits. In this, the final technical report for Spire's two-year MIMIC contract, we report the results of our work. The main objectives of Spire's MIMIC Phase 3 Program, as outlined in the Statement of Work, were as follows: Optimize the MOCVD growth conditions for the best possible electrical and morphological gallium arsenide. Optimization should include substrate and source qualification as well as determination of the optimum reactor growth conditions; Perform all work on 75 millimeter diameter wafers, using a reactor capable of at least three wafers per run; and Evaluate epitaxial layers using electrical, optical, and morphological tests to obtain thickness, carrier concentration, and mobility data across wafers.

Cerebellum and Integration of Neural Networks in Dual-Task Processing

PubMed Central

Wu, Tao; Liu, Jun; Hallett, Mark; Zheng, Zheng; Chan, Piu

2014-01-01

Performing two tasks simultaneously (dual-task) is common in human daily life. The neural correlates of dual-task processing remain unclear. In the current study, we used a dual motor and counting task with functional MRI (fMRI) to determine whether there are any areas additionally activated for dual-task performance. Moreover, we investigated the functional connectivity of these added activated areas, as well as the training effect on brain activity and connectivity. We found that the right cerebellar vermis, left lobule V of the cerebellar anterior lobe and precuneus are additionally activated for this type of dual-tasking. These cerebellar regions had functional connectivity with extensive motor- and cognitive-related regions. Dual-task training induced less activation in several areas, but increased the functional connectivity between these cerebellar regions and numbers of motor- and cognitive-related areas. Our findings demonstrate that some regions within the cerebellum can be additionally activated with dual-task performance. Their role in dual motor and cognitive task processes is likely to integrate motor and cognitive networks, and may be involved in adjusting these networks to be more efficient in order to perform dual-tasking properly. The connectivity of the precuneus differs from the cerebellar regions. A possible role of the precuneus in dual-task may be monitoring the operation of active brain networks. PMID:23063842

Brain activation and deactivation during location and color working memory tasks in 11-13-year-old children.

PubMed

Vuontela, Virve; Steenari, Maija-Riikka; Aronen, Eeva T; Korvenoja, Antti; Aronen, Hannu J; Carlson, Synnöve

2009-02-01

Using functional magnetic resonance imaging (fMRI) and n-back tasks we investigated whether, in 11-13-year-old children, spatial (location) and nonspatial (color) information is differentially processed during visual attention (0-back) and working memory (WM) (2-back) tasks and whether such cognitive task performance, compared to a resting state, results in regional deactivation. The location 0-back task, compared to the color 0-back task, activated segregated areas in the frontal, parietal and occipital cortices whereas no differentially activated voxels were obtained when location and color 2-back tasks were directly contrasted. Several midline cortical areas were less active during 0- and 2-back task performance than resting state. The task-induced deactivation increased with task difficulty as demonstrated by larger deactivation during 2-back than 0-back tasks. The results suggest that, in 11-13-year-old children, the visual attentional network is differently recruited by spatial and nonspatial information processing, but the functional organization of cortical activation in WM in this age group is not based on the type of information processed. Furthermore, 11-13-year-old children exhibited a similar pattern of cortical deactivation that has been reported in adults during cognitive task performance compared to a resting state.

How Semantic Categorization Influences Inhibitory Processing in Middle-Childhood: An Event Related Potentials study

ERIC Educational Resources Information Center

Maguire, Mandy J.; White, Joshua; Brier, Matthew R.

2011-01-01

Throughout middle-childhood, inhibitory processes, which underlie many higher order cognitive tasks, are developing. Little is known about how inhibitory processes change as a task becomes conceptually more difficult during these important years. In adults, as Go/NoGo tasks become more difficult there is a systematic decrease in the P3 NoGo…

A Processing Approach to the Working Memory/Long-Term Memory Distinction: Evidence from the Levels-of-Processing Span Task

ERIC Educational Resources Information Center

Rose, Nathan S.; Craik, Fergus I. M.

2012-01-01

Recent theories suggest that performance on working memory (WM) tasks involves retrieval from long-term memory (LTM). To examine whether WM and LTM tests have common principles, Craik and Tulving's (1975) levels-of-processing paradigm, which is known to affect LTM, was administered as a WM task: Participants made uppercase, rhyme, or…

Brain activity during auditory and visual phonological, spatial and simple discrimination tasks.

PubMed

Salo, Emma; Rinne, Teemu; Salonen, Oili; Alho, Kimmo

2013-02-16

We used functional magnetic resonance imaging to measure human brain activity during tasks demanding selective attention to auditory or visual stimuli delivered in concurrent streams. Auditory stimuli were syllables spoken by different voices and occurring in central or peripheral space. Visual stimuli were centrally or more peripherally presented letters in darker or lighter fonts. The participants performed a phonological, spatial or "simple" (speaker-gender or font-shade) discrimination task in either modality. Within each modality, we expected a clear distinction between brain activations related to nonspatial and spatial processing, as reported in previous studies. However, within each modality, different tasks activated largely overlapping areas in modality-specific (auditory and visual) cortices, as well as in the parietal and frontal brain regions. These overlaps may be due to effects of attention common for all three tasks within each modality or interaction of processing task-relevant features and varying task-irrelevant features in the attended-modality stimuli. Nevertheless, brain activations caused by auditory and visual phonological tasks overlapped in the left mid-lateral prefrontal cortex, while those caused by the auditory and visual spatial tasks overlapped in the inferior parietal cortex. These overlapping activations reveal areas of multimodal phonological and spatial processing. There was also some evidence for intermodal attention-related interaction. Most importantly, activity in the superior temporal sulcus elicited by unattended speech sounds was attenuated during the visual phonological task in comparison with the other visual tasks. This effect might be related to suppression of processing irrelevant speech presumably distracting the phonological task involving the letters. Copyright © 2012 Elsevier B.V. All rights reserved.

Toward a process-level view of distributed healthcare tasks: Medication management as a case study.

PubMed

Werner, Nicole E; Malkana, Seema; Gurses, Ayse P; Leff, Bruce; Arbaje, Alicia I

2017-11-01

We aim to highlight the importance of using a process-level view in analyzing distributed healthcare tasks through a case study analysis of medication management (MM). MM during older adults' hospital-to-skilled-home-healthcare (SHHC) transitions is a healthcare process with tasks distributed across people, organizations, and time. MM has typically been studied at the task level, but a process-level is needed to fully understand and improve MM during transitions. A process-level view allows for a broader investigation of how tasks are distributed throughout the work system through an investigation of interactions and the resultant emergent properties. We studied MM during older adults' hospital-to-SHHC transitions through interviews and observations with 60 older adults, their 33 caregivers, and 79 SHHC providers at 5 sites associated with 3 SHHC agencies. Study findings identified key cross-system characteristics not observable at the task-level: (1) identification of emergent properties (e.g., role ambiguity, loosely-coupled teams performing MM) and associated barriers; and (2) examination of barrier propagation across system boundaries. Findings highlight the importance of a process-level view of healthcare delivery occurring across system boundaries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reconstructing the regulatory circuit of cell fate determination in yeast mating response.

PubMed

Shao, Bin; Yuan, Haiyu; Zhang, Rongfei; Wang, Xuan; Zhang, Shuwen; Ouyang, Qi; Hao, Nan; Luo, Chunxiong

2017-07-01

Massive technological advances enabled high-throughput measurements of proteomic changes in biological processes. However, retrieving biological insights from large-scale protein dynamics data remains a challenging task. Here we used the mating differentiation in yeast Saccharomyces cerevisiae as a model and developed integrated experimental and computational approaches to analyze the proteomic dynamics during the process of cell fate determination. When exposed to a high dose of mating pheromone, the yeast cell undergoes growth arrest and forms a shmoo-like morphology; however, at intermediate doses, chemotropic elongated growth is initialized. To understand the gene regulatory networks that control this differentiation switch, we employed a high-throughput microfluidic imaging system that allows real-time and simultaneous measurements of cell growth and protein expression. Using kinetic modeling of protein dynamics, we classified the stimulus-dependent changes in protein abundance into two sources: global changes due to physiological alterations and gene-specific changes. A quantitative framework was proposed to decouple gene-specific regulatory modes from the growth-dependent global modulation of protein abundance. Based on the temporal patterns of gene-specific regulation, we established the network architectures underlying distinct cell fates using a reverse engineering method and uncovered the dose-dependent rewiring of gene regulatory network during mating differentiation. Furthermore, our results suggested a potential crosstalk between the pheromone response pathway and the target of rapamycin (TOR)-regulated ribosomal biogenesis pathway, which might underlie a cell differentiation switch in yeast mating response. In summary, our modeling approach addresses the distinct impacts of the global and gene-specific regulation on the control of protein dynamics and provides new insights into the mechanisms of cell fate determination. We anticipate that our integrated experimental and modeling strategies could be widely applicable to other biological systems.

Reading Rate, Readability, and Variations in Task-Induced Processing

ERIC Educational Resources Information Center

Coke, Esther U.

1976-01-01

This study explored the hypothesis that task variables account for previous findings that reading rate is unaffected by readability. The findings suggest that when appropriate reading tasks are chosen, reading rate can be used to infer underlying processes in reading. (Author/DEP)

Dyslexic Participants Show Intact Spontaneous Categorization Processes

ERIC Educational Resources Information Center

Nikolopoulos, Dimitris S.; Pothos, Emmanuel M.

2009-01-01

We examine the performance of dyslexic participants on an unsupervised categorization task against that of matched non-dyslexic control participants. Unsupervised categorization is a cognitive process critical for conceptual development. Existing research in dyslexia has emphasized perceptual tasks and supervised categorization tasks (for which…

Prior cognitive activity implicitly modulates subsequent emotional responses to subliminally presented emotional stimuli.

PubMed

Iida, Saea; Nakao, Takashi; Ohira, Hideki

2012-06-01

It has been reported that engagement in several kinds of cognitive activity can successfully inhibit unpleasant emotions. In this study, we tried to replicate the previous finding that cognitive activity can modulate subsequent psychological and physiological emotional processes and to investigate whether prior cognitive activity can attenuate implicit emotional processes triggered by subliminal emotional stimuli. Sixty students were randomly divided into three groups (cognitive task group, noncognitive task group, control group). The cognitive task group was asked to engage in an n-back task, while the control group was asked to stay calm. The noncognitive task group was asked to do a handgrip-squeezing task. All participants then engaged in a version of a subliminal affective priming task where they were unconsciously exposed to affectively negative pictures. The cognitive task group showed lower negative experiences after the subliminal affective priming task and a substantial reduction in their heart rate responses, as compared with the other groups. These results provide evidence that engagement in cognitive activity can attenuate emotional processes in an automatic and unconscious manner.

Age-related emotional bias in processing two emotionally valenced tasks.

PubMed

Allen, Philip A; Lien, Mei-Ching; Jardin, Elliott

2017-01-01

Previous studies suggest that older adults process positive emotions more efficiently than negative emotions, whereas younger adults show the reverse effect. We examined whether this age-related difference in emotional bias still occurs when attention is engaged in two emotional tasks. We used a psychological refractory period paradigm and varied the emotional valence of Task 1 and Task 2. In both experiments, Task 1 was emotional face discrimination (happy vs. angry faces) and Task 2 was sound discrimination (laugh, punch, vs. cork pop in Experiment 1 and laugh vs. scream in Experiment 2). The backward emotional correspondence effect for positively and negatively valenced Task 2 on Task 1 was measured. In both experiments, younger adults showed a backward correspondence effect from a negatively valenced Task 2, suggesting parallel processing of negatively valenced stimuli. Older adults showed similar negativity bias in Experiment 2 with a more salient negative sound ("scream" relative to "punch"). These results are consistent with an arousal-bias competition model [Mather and Sutherland (Perspectives in Psychological Sciences 6:114-133, 2011)], suggesting that emotional arousal modulates top-down attentional control settings (emotional regulation) with age.

Chang'E-3 data pre-processing system based on scientific workflow

NASA Astrophysics Data System (ADS)

tan, xu; liu, jianjun; wang, yuanyuan; yan, wei; zhang, xiaoxia; li, chunlai

2016-04-01

The Chang'E-3(CE3) mission have obtained a huge amount of lunar scientific data. Data pre-processing is an important segment of CE3 ground research and application system. With a dramatic increase in the demand of data research and application, Chang'E-3 data pre-processing system(CEDPS) based on scientific workflow is proposed for the purpose of making scientists more flexible and productive by automating data-driven. The system should allow the planning, conduct and control of the data processing procedure with the following possibilities: • describe a data processing task, include:1)define input data/output data, 2)define the data relationship, 3)define the sequence of tasks,4)define the communication between tasks,5)define mathematical formula, 6)define the relationship between task and data. • automatic processing of tasks. Accordingly, Describing a task is the key point whether the system is flexible. We design a workflow designer which is a visual environment for capturing processes as workflows, the three-level model for the workflow designer is discussed:1) The data relationship is established through product tree.2)The process model is constructed based on directed acyclic graph(DAG). Especially, a set of process workflow constructs, including Sequence, Loop, Merge, Fork are compositional one with another.3)To reduce the modeling complexity of the mathematical formulas using DAG, semantic modeling based on MathML is approached. On top of that, we will present how processed the CE3 data with CEDPS.

Construction of mammographic examination process ontology using bottom-up hierarchical task analysis.

PubMed

Yagahara, Ayako; Yokooka, Yuki; Jiang, Guoqian; Tsuji, Shintarou; Fukuda, Akihisa; Nishimoto, Naoki; Kurowarabi, Kunio; Ogasawara, Katsuhiko

2018-03-01

Describing complex mammography examination processes is important for improving the quality of mammograms. It is often difficult for experienced radiologic technologists to explain the process because their techniques depend on their experience and intuition. In our previous study, we analyzed the process using a new bottom-up hierarchical task analysis and identified key components of the process. Leveraging the results of the previous study, the purpose of this study was to construct a mammographic examination process ontology to formally describe the relationships between the process and image evaluation criteria to improve the quality of mammograms. First, we identified and created root classes: task, plan, and clinical image evaluation (CIE). Second, we described an "is-a" relation referring to the result of the previous study and the structure of the CIE. Third, the procedural steps in the ontology were described using the new properties: "isPerformedBefore," "isPerformedAfter," and "isPerformedAfterIfNecessary." Finally, the relationships between tasks and CIEs were described using the "isAffectedBy" property to represent the influence of the process on image quality. In total, there were 219 classes in the ontology. By introducing new properties related to the process flow, a sophisticated mammography examination process could be visualized. In relationships between tasks and CIEs, it became clear that the tasks affecting the evaluation criteria related to positioning were greater in number than those for image quality. We developed a mammographic examination process ontology that makes knowledge explicit for a comprehensive mammography process. Our research will support education and help promote knowledge sharing about mammography examination expertise.

Vietnamese children and language-based processing tasks.

PubMed

Hwa-Froelich, Deborah A; Matsuo, Hisako

2005-07-01

Vietnamese children's performance on language-based processing tasks of fast-mapping (FM) word-learning and dynamic assessment (DA) word- and rule-learning tasks were investigated. Twenty-one first- and second-generation Vietnamese preschool children participated in this study. All children were enrolled in 2 Head Start programs in a large city in the Midwest. All children had passed a developmental assessment and routine speech, language, and hearing screenings. All participants were taught 4 invented monosyllabic words in an FM word task, an invented monosyllabic suffix rule (-po) meaning "a part of" in a DA rule task, and 4 invented bisyllabic words in a DA word task. Potential relationships among task performances were investigated. Receptive task performances, expressive task performances, and task totals were added to create receptive total, expressive total, and accumulated performance total (APT) scores. Relationships among receptive total, expressive total, and APT scores were also investigated. Significant correlations were found between FM word, DA rule, and the receptive total. The expressive total correlated with all task total scores, APT, age, and modifiability scores. Modifiability scores correlated with the two DA tasks, expressive total, and the APT. Findings indicate that FM word and the expressive total were positively correlated with most of the other tasks, composite totals, and age. Performance on language-based processing tasks may provide valuable information for separating typically developing Vietnamese preschool children from their peers with language disorders. Practitioners should consider linguistic characteristics of target stimuli. Comparisons should include task, receptive, expressive, and APT.

Development of advanced methods for continuous Czochralski growth. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Wolfson, R. G.; Sibley, C. B.

1978-01-01

The three components required to modify the furnace for batch and continuous recharging with granular silicon were designed. The feasibility of extended growth cycles up to 40 hours long was demonstrated by a recharge simulation experiment; a 6 inch diameter crystal was pulled from a 20 kg charge, remelted, and pulled again for a total of four growth cycles, 59-1/8 inch of body length, and approximately 65 kg of calculated mass.

Large-area sheet task advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Schruben, J.

1982-01-01

The computer code for calculating web temperature distribution was expanded to provide a graphics output in addition to numerical and punch card output. The new code was used to examine various modifications of the J419 configuration and, on the basis of the results, a new growth geometry was designed. Additionally, several mathematically defined temperature profiles were evaluated for the effects of the free boundary (growth front) on the thermal stress generation. Experimental growth runs were made with modified J419 configurations to complement the modeling work. A modified J435 configuration was evaluated.

IBS simulation with different RF configurations in RHIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Fedotov, A.; Minty, M.

It is a crucial task to understand the beam emittance growth during RHIC cycle and the underlying causes. One would benefit not just for the current operation of RHIC, also for the design of eRHIC. This report focuses on the Intra-Beam Scattering (IBS) contribution to the emittance growth of the proton beam with two different configurations of RF system. The answers to these questions will be given in the end of the report; can IBS explain the emittance growth all alone? What’s the difference of IBS growth rates for different RF configurations?

Materials processing in space program tasks

NASA Technical Reports Server (NTRS)

Mckannan, E. C. (Editor)

1978-01-01

A list of active research tasks as of the end of 1978 of the Materials Processing in Space Program of the Office of Space and Terrestrial Applications, involving several NASA Centers and other organizations is reported. An overview of the program scope for managers and scientists in industry, university and government communities is provided. The program, its history, strategy and overall goal; the organizational structures and people involved; and each research task are described. Tasks are categorized by ground based research according to four process areas. Cross references to the performing organizations and principal investigators are provided.

Task and spatial frequency modulations of object processing: an EEG study.

PubMed

Craddock, Matt; Martinovic, Jasna; Müller, Matthias M

2013-01-01

Visual object processing may follow a coarse-to-fine sequence imposed by fast processing of low spatial frequencies (LSF) and slow processing of high spatial frequencies (HSF). Objects can be categorized at varying levels of specificity: the superordinate (e.g. animal), the basic (e.g. dog), or the subordinate (e.g. Border Collie). We tested whether superordinate and more specific categorization depend on different spatial frequency ranges, and whether any such dependencies might be revealed by or influence signals recorded using EEG. We used event-related potentials (ERPs) and time-frequency (TF) analysis to examine the time course of object processing while participants performed either a grammatical gender-classification task (which generally forces basic-level categorization) or a living/non-living judgement (superordinate categorization) on everyday, real-life objects. Objects were filtered to contain only HSF or LSF. We found a greater positivity and greater negativity for HSF than for LSF pictures in the P1 and N1 respectively, but no effects of task on either component. A later, fronto-central negativity (N350) was more negative in the gender-classification task than the superordinate categorization task, which may indicate that this component relates to semantic or syntactic processing. We found no significant effects of task or spatial frequency on evoked or total gamma band responses. Our results demonstrate early differences in processing of HSF and LSF content that were not modulated by categorization task, with later responses reflecting such higher-level cognitive factors.

Implicit and Explicit Attention to Pictures and Words: An fMRI-Study of Concurrent Emotional Stimulus Processing.

PubMed

Flaisch, Tobias; Imhof, Martin; Schmälzle, Ralf; Wentz, Klaus-Ulrich; Ibach, Bernd; Schupp, Harald T

2015-01-01

The present study utilized functional magnetic resonance imaging (fMRI) to examine the neural processing of concurrently presented emotional stimuli under varying explicit and implicit attention demands. Specifically, in separate trials, participants indicated the category of either pictures or words. The words were placed over the center of the pictures and the picture-word compound-stimuli were presented for 1500 ms in a rapid event-related design. The results reveal pronounced main effects of task and emotion: the picture categorization task prompted strong activations in visual, parietal, temporal, frontal, and subcortical regions; the word categorization task evoked increased activation only in left extrastriate cortex. Furthermore, beyond replicating key findings regarding emotional picture and word processing, the results point to a dissociation of semantic-affective and sensory-perceptual processes for words: while emotional words engaged semantic-affective networks of the left hemisphere regardless of task, the increased activity in left extrastriate cortex associated with explicitly attending to words was diminished when the word was overlaid over an erotic image. Finally, we observed a significant interaction between Picture Category and Task within dorsal visual-associative regions, inferior parietal, and dorsolateral, and medial prefrontal cortices: during the word categorization task, activation was increased in these regions when the words were overlaid over erotic as compared to romantic pictures. During the picture categorization task, activity in these areas was relatively decreased when categorizing erotic as compared to romantic pictures. Thus, the emotional intensity of the pictures strongly affected brain regions devoted to the control of task-related word or picture processing. These findings are discussed with respect to the interplay of obligatory stimulus processing with task-related attentional control mechanisms.

Functional Activation during the Rapid Visual Information Processing Task in a Middle Aged Cohort: An fMRI Study.

PubMed

Neale, Chris; Johnston, Patrick; Hughes, Matthew; Scholey, Andrew

2015-01-01

The Rapid Visual Information Processing (RVIP) task, a serial discrimination task where task performance believed to reflect sustained attention capabilities, is widely used in behavioural research and increasingly in neuroimaging studies. To date, functional neuroimaging research into the RVIP has been undertaken using block analyses, reflecting the sustained processing involved in the task, but not necessarily the transient processes associated with individual trial performance. Furthermore, this research has been limited to young cohorts. This study assessed the behavioural and functional magnetic resonance imaging (fMRI) outcomes of the RVIP task using both block and event-related analyses in a healthy middle aged cohort (mean age = 53.56 years, n = 16). The results show that the version of the RVIP used here is sensitive to changes in attentional demand processes with participants achieving a 43% accuracy hit rate in the experimental task compared with 96% accuracy in the control task. As shown by previous research, the block analysis revealed an increase in activation in a network of frontal, parietal, occipital and cerebellar regions. The event related analysis showed a similar network of activation, seemingly omitting regions involved in the processing of the task (as shown in the block analysis), such as occipital areas and the thalamus, providing an indication of a network of regions involved in correct trial performance. Frontal (superior and inferior frontal gryi), parietal (precuenus, inferior parietal lobe) and cerebellar regions were shown to be active in both the block and event-related analyses, suggesting their importance in sustained attention/vigilance. These networks and the differences between them are discussed in detail, as well as implications for future research in middle aged cohorts.

Implicit and Explicit Attention to Pictures and Words: An fMRI-Study of Concurrent Emotional Stimulus Processing

PubMed Central

Flaisch, Tobias; Imhof, Martin; Schmälzle, Ralf; Wentz, Klaus-Ulrich; Ibach, Bernd; Schupp, Harald T.

2015-01-01

The present study utilized functional magnetic resonance imaging (fMRI) to examine the neural processing of concurrently presented emotional stimuli under varying explicit and implicit attention demands. Specifically, in separate trials, participants indicated the category of either pictures or words. The words were placed over the center of the pictures and the picture-word compound-stimuli were presented for 1500 ms in a rapid event-related design. The results reveal pronounced main effects of task and emotion: the picture categorization task prompted strong activations in visual, parietal, temporal, frontal, and subcortical regions; the word categorization task evoked increased activation only in left extrastriate cortex. Furthermore, beyond replicating key findings regarding emotional picture and word processing, the results point to a dissociation of semantic-affective and sensory-perceptual processes for words: while emotional words engaged semantic-affective networks of the left hemisphere regardless of task, the increased activity in left extrastriate cortex associated with explicitly attending to words was diminished when the word was overlaid over an erotic image. Finally, we observed a significant interaction between Picture Category and Task within dorsal visual-associative regions, inferior parietal, and dorsolateral, and medial prefrontal cortices: during the word categorization task, activation was increased in these regions when the words were overlaid over erotic as compared to romantic pictures. During the picture categorization task, activity in these areas was relatively decreased when categorizing erotic as compared to romantic pictures. Thus, the emotional intensity of the pictures strongly affected brain regions devoted to the control of task-related word or picture processing. These findings are discussed with respect to the interplay of obligatory stimulus processing with task-related attentional control mechanisms. PMID:26733895

Benefits of interhemispheric integration on the Japanese Kana script-matching tasks.

PubMed

Yoshizaki, K; Tsuji, Y

2000-02-01

We tested Banich's hypothesis that the benefits of bihemispheric processing were enhanced as task complexity increased, when some procedural shortcomings in the previous studies were overcome by using Japanese Kana script-matching tasks. In Exp. 1, the 20 right-handed subjects were given the Physical-Identity task (Katakana-Katakana scripts matching) and the Name-Identity task (Katakana-Hiragana scripts matching). On both tasks, a pair of Kana scripts was tachistoscopically presented in the left, right, and bilateral visual fields. Distractor stimuli were also presented with target Kana scripts on both tasks to equate the processing load between the hemispheres. Analysis showed that, while a bilateral visual-field advantage was found on the name-identity task, a unilateral visual-field advantage was found on the physical-identity task, suggesting that, as the computational complexity of the encoding stage was enhanced, the benefits of bilateral hemispheric processing increased. In Exp. 2, the 16 right-handed subjects were given the same physical-identity task as in Exp. 1, except Hiragana scripts were used as distractors instead of digits to enhance task difficulty. Analysis showed no differences in performance between the unilateral and bilateral visual fields. Taking into account these results of physical-identity tasks for both Exps. 1 and 2, enhancing task demand in the stage of ignoring distractors made the unilateral visual-field advantage obtained in Exp. 1 disappear in Exp. 2. These results supported Banich's hypothesis.

A human brain atlas derived via n-cut parcellation of resting-state and task-based fMRI data

PubMed Central

James, G. Andrew; Hazaroglu, Onder; Bush, Keith A.

2015-01-01

The growth of functional MRI has led to development of human brain atlases derived by parcellating resting-state connectivity patterns into functionally independent regions of interest (ROIs). All functional atlases to date have been derived from resting-state fMRI data. But given that functional connectivity between regions varies with task, we hypothesized that an atlas incorporating both resting-state and task-based fMRI data would produce an atlas with finer characterization of task-relevant regions than an atlas derived from resting-state alone. To test this hypothesis, we derived parcellation atlases from twenty-nine healthy adult participants enrolled in the Cognitive Connectome project, an initiative to improve functional MRI’s translation into clinical decision-making by mapping normative variance in brain-behavior relationships. Participants underwent resting-state and task-based fMRI spanning nine cognitive domains: motor, visuospatial, attention, language, memory, affective processing, decision-making, working memory, and executive function. Spatially constrained n-cut parcellation derived brain atlases using (1) all participants’ functional data (Task) or (2) a single resting-state scan (Rest). An atlas was also derived from random parcellation for comparison purposes (Random). Two methods were compared: (1) a parcellation applied to the group’s mean edge weights (mean), and (2) a two-stage approach with parcellation of individual edge weights followed by parcellation of mean binarized edges (two-stage). The resulting Task and Rest atlases had significantly greater similarity with each other (mean Jaccard indices JI= 0.72–0.85) than with the Random atlases (JI=0.59–0.63; all p<0.001 after Bonferroni correction). Task and Rest atlas similarity was greatest for the two-stage method (JI=0.85), which has been shown as more robust than the mean method; these atlases also better reproduced voxelwise seed maps of the left dorsolateral prefrontal cortex during rest and performing the n-back working memory task (r=0.75–0.80) than the Random atlases (r=0.64–0.72), further validating their utility. We expected regions governing higher-order cognition (such as frontal and anterior temporal lobes) to show greatest difference between Task and Rest atlases; contrary to expectations, these areas had greatest similarity between atlases. Our findings indicate that atlases derived from parcellation of task-based and resting-state fMRI data are highly comparable, and existing resting-state atlases are suitable for task-based analyses. We introduce an anatomically labeled fMRI-derived whole-brain human atlas for future Cognitive Connectome analyses. PMID:26523655

A human brain atlas derived via n-cut parcellation of resting-state and task-based fMRI data.

PubMed

James, George Andrew; Hazaroglu, Onder; Bush, Keith A

2016-02-01

The growth of functional MRI has led to development of human brain atlases derived by parcellating resting-state connectivity patterns into functionally independent regions of interest (ROIs). All functional atlases to date have been derived from resting-state fMRI data. But given that functional connectivity between regions varies with task, we hypothesized that an atlas incorporating both resting-state and task-based fMRI data would produce an atlas with finer characterization of task-relevant regions than an atlas derived from resting-state alone. To test this hypothesis, we derived parcellation atlases from twenty-nine healthy adult participants enrolled in the Cognitive Connectome project, an initiative to improve functional MRI's translation into clinical decision-making by mapping normative variance in brain-behavior relationships. Participants underwent resting-state and task-based fMRI spanning nine cognitive domains: motor, visuospatial, attention, language, memory, affective processing, decision-making, working memory, and executive function. Spatially constrained n-cut parcellation derived brain atlases using (1) all participants' functional data (Task) or (2) a single resting-state scan (Rest). An atlas was also derived from random parcellation for comparison purposes (Random). Two methods were compared: (1) a parcellation applied to the group's mean edge weights (mean), and (2) a two-stage approach with parcellation of individual edge weights followed by parcellation of mean binarized edges (two-stage). The resulting Task and Rest atlases had significantly greater similarity with each other (mean Jaccard indices JI=0.72-0.85) than with the Random atlases (JI=0.59-0.63; all p<0.001 after Bonferroni correction). Task and Rest atlas similarity was greatest for the two-stage method (JI=0.85), which has been shown as more robust than the mean method; these atlases also better reproduced voxelwise seed maps of the left dorsolateral prefrontal cortex during rest and performing the n-back working memory task (r=0.75-0.80) than the Random atlases (r=0.64-0.72), further validating their utility. We expected regions governing higher-order cognition (such as frontal and anterior temporal lobes) to show greatest difference between Task and Rest atlases; contrary to expectations, these areas had greatest similarity between atlases. Our findings indicate that atlases derived from parcellation of task-based and resting-state fMRI data are highly comparable, and existing resting-state atlases are suitable for task-based analyses. We introduce an anatomically labeled fMRI-derived whole-brain human atlas for future Cognitive Connectome analyses. Copyright © 2015 Elsevier Inc. All rights reserved.

Phone Conversation while Processing Information: Chronometric Analysis of Load Effects in Everyday-media Multitasking

PubMed Central

Steinborn, Michael B.; Huestegge, Lynn

2017-01-01

This is a pilot study that examined the effect of cell-phone conversation on cognition using a continuous multitasking paradigm. Current theorizing argues that phone conversation affects behavior (e.g., driving) by interfering at a level of cognitive processes (not peripheral activity) and by implying an attentional-failure account. Within the framework of an intermittent spare–utilized capacity threading model, we examined the effect of aspects of (secondary-task) phone conversation on (primary-task) continuous arithmetic performance, asking whether phone use makes components of automatic and controlled information-processing (i.e., easy vs. hard mental arithmetic) run more slowly, or alternatively, makes processing run less reliably albeit with the same processing speed. The results can be summarized as follows: While neither expecting a text message nor expecting an impending phone call had any detrimental effects on performance, active phone conversation was clearly detrimental to primary-task performance. Crucially, the decrement imposed by secondary-task (conversation) was not due to a constant slowdown but is better be characterized by an occasional breakdown of information processing, which differentially affected automatic and controlled components of primary-task processing. In conclusion, these findings support the notion that phone conversation makes individuals not constantly slower but more vulnerable to commit attention failure, and in this way, hampers stability of (primary-task) information processing. PMID:28634458

Phone Conversation while Processing Information: Chronometric Analysis of Load Effects in Everyday-media Multitasking.

PubMed

Steinborn, Michael B; Huestegge, Lynn

2017-01-01

This is a pilot study that examined the effect of cell-phone conversation on cognition using a continuous multitasking paradigm. Current theorizing argues that phone conversation affects behavior (e.g., driving) by interfering at a level of cognitive processes (not peripheral activity) and by implying an attentional-failure account. Within the framework of an intermittent spare-utilized capacity threading model, we examined the effect of aspects of (secondary-task) phone conversation on (primary-task) continuous arithmetic performance, asking whether phone use makes components of automatic and controlled information-processing (i.e., easy vs. hard mental arithmetic) run more slowly, or alternatively, makes processing run less reliably albeit with the same processing speed. The results can be summarized as follows: While neither expecting a text message nor expecting an impending phone call had any detrimental effects on performance, active phone conversation was clearly detrimental to primary-task performance. Crucially, the decrement imposed by secondary-task (conversation) was not due to a constant slowdown but is better be characterized by an occasional breakdown of information processing, which differentially affected automatic and controlled components of primary-task processing. In conclusion, these findings support the notion that phone conversation makes individuals not constantly slower but more vulnerable to commit attention failure, and in this way, hampers stability of (primary-task) information processing.

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

ERIC Educational Resources Information Center

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

2008-01-01

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

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

ERIC Educational Resources Information Center

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…

Micromanagement--a costly management style.

PubMed

Collins, Sandra K; Collins, Kevin S

2002-01-01

Micromanagement can be advantageous in certain short-term situations, such as while training new employees, increasing productivity of underperforming employees, controlling high-risk issues, and when there can be no question of who is in charge. However, the costs associated with long-term micromanagement can be exorbitant. Symptoms such as low employee morale, high staff turnover, reduction of productivity and patient dissatisfaction can be associated with micromanagement. The negative impacts are so intense that it is labeled among the top three reasons employees resign. Ultimately, micromanagement leads to decreased growth potential in a department. Managers who put too much emphasis on daily operational details can miss the broader picture and fail to plan for departmental expansion. Eventually, many micromanagers find themselves at considerable risk of burnout. Changing behavior associated with micromanagement can be a lengthy and difficult process. As with most problems, the first step is to realize that there is behavior that needs to be changed and to understand how it negatively impacts the department. Conducting a self-assessment of one's leadership style can be advantageous in this process. The true task is to find a balance between effectively performing daily obligations and strategically planning for the future. This task typically involves proper delegation of duties, and that in itself is a difficult challenge. Proper delegation of tasks may be the primary key to combating micromanaging behavior, however, some other suggestions include: 1. Develop a vision of what the department will look like in the future. 2. Hire people with the right skills for the job. 3. Develop a policy and procedures manual. 4. Develop solid lines of communication between managers and subordinates. 5. Expect some employee errors. Mistakes are an important process in the learning experience and should be viewed as a training expense. Employees who are allowed to be self-directed will be motivated to be more productive. Staffing issues such as low morale and high turnover will decrease; patient satisfaction will increase simultaneously.

Hot and Cool Executive Functions in Adolescence: Development and Contributions to Important Developmental Outcomes.

PubMed

Poon, Kean

2017-01-01

Despite significant theoretical advancement in the area of child neuropsychology, limited attention has been paid to the developmental features of adolescence. The present study intends to address this issue in relation to executive function (EF). EF refers to the psychological processes that underlie goal-directed behavior; recent studies separate cool EF (psychological process involves pure logic and critical analysis) and hot EF (psychological process driven by emotion). Although neurological findings suggest that adolescence is a sensitive period for EF development, data on comparing the developmental progression in hot or cool EFs is highly missing. Moreover, while evidence has confirmed the relationships between EF and day-to-day functioning, whether and how hot and cool EFs contribute to core developmental outcomes in adolescence is still remained unknown. The current study aims to enhance our understanding of the development and impacts of hot and cool EFs in adolescence. A total of 136 typically developing adolescents from age 12 to 17 completed four cool EF tasks including Backward digit span, Contingency naming test, Stockings of Cambridge, and Stroop Color and Word test, and one hot task on Cambridge gambling task. Data on academic performance and psychological adjustment was also collected. Results showed that cool and hot EF exhibited different patterns of age-related growth in adolescence. Specifically, cool EF ascended with age while hot EF showed a bell-shaped development. Moreover, there were correlations among cool EF measures but no association between cool and hot EFs. Further, cool EF was a better predictor of academic performance, while hot EF uniquely related to emotional problems. The results provide evidence for the association among cool EF tests and the differentiation of hot and cool EFs. The bell-shaped development of hot EF might suggest a period of heightened risk-taking propensity in middle adolescence. Given the plastic nature of EF, especially over adolescence, the current findings may have practical implications for future EF identification and training.

Hot and Cool Executive Functions in Adolescence: Development and Contributions to Important Developmental Outcomes

PubMed Central

Poon, Kean

2018-01-01

Despite significant theoretical advancement in the area of child neuropsychology, limited attention has been paid to the developmental features of adolescence. The present study intends to address this issue in relation to executive function (EF). EF refers to the psychological processes that underlie goal-directed behavior; recent studies separate cool EF (psychological process involves pure logic and critical analysis) and hot EF (psychological process driven by emotion). Although neurological findings suggest that adolescence is a sensitive period for EF development, data on comparing the developmental progression in hot or cool EFs is highly missing. Moreover, while evidence has confirmed the relationships between EF and day-to-day functioning, whether and how hot and cool EFs contribute to core developmental outcomes in adolescence is still remained unknown. The current study aims to enhance our understanding of the development and impacts of hot and cool EFs in adolescence. A total of 136 typically developing adolescents from age 12 to 17 completed four cool EF tasks including Backward digit span, Contingency naming test, Stockings of Cambridge, and Stroop Color and Word test, and one hot task on Cambridge gambling task. Data on academic performance and psychological adjustment was also collected. Results showed that cool and hot EF exhibited different patterns of age-related growth in adolescence. Specifically, cool EF ascended with age while hot EF showed a bell-shaped development. Moreover, there were correlations among cool EF measures but no association between cool and hot EFs. Further, cool EF was a better predictor of academic performance, while hot EF uniquely related to emotional problems. The results provide evidence for the association among cool EF tests and the differentiation of hot and cool EFs. The bell-shaped development of hot EF might suggest a period of heightened risk-taking propensity in middle adolescence. Given the plastic nature of EF, especially over adolescence, the current findings may have practical implications for future EF identification and training. PMID:29367850

Delegation--A Fundamental Management Process.

ERIC Educational Resources Information Center

Rees, Ruth

Administrators may employ delegation to perform work effectively, increase their own effectiveness, and advance the development of subordinates through job enrichment. The steps in the delegation process include task identification, assessment of skills necessary to execute the task, selection of the subordinate for the task, communication of the…

Levels of Information Processing in a Fitts law task (LIPFitts)

NASA Technical Reports Server (NTRS)

Mosier, K. L.; Hart, S. G.

1986-01-01

State-of-the-art flight technology has restructured the task of human operators, decreasing the need for physical and sensory resources, and increasing the quantity of cognitive effort required, changing it qualitatively. Recent technological advances have the most potential for impacting a pilot in two areas: performance and mental workload. In an environment in which timing is critical, additional cognitive processing can cause performance decrements, and increase a pilot's perception of the mental workload involved. The effects of stimulus processing demands on motor response performance and subjective mental workload are examined, using different combinations of response selection and target acquisition tasks. The information processing demands of the response selection were varied (e.g., Sternberg memory set tasks, math equations, pattern matching), as was the difficulty of the response execution. Response latency as well as subjective workload ratings varied in accordance with the cognitive complexity of the task. Movement times varied according to the difficulty of the response execution task. Implications in terms of real-world flight situations are discussed.

Flexible Visual Processing in Young Adults with Autism: The Effects of Implicit Learning on a Global-Local Task

ERIC Educational Resources Information Center

Hayward, Dana A.; Shore, David I.; Ristic, Jelena; Kovshoff, Hanna; Iarocci, Grace; Mottron, Laurent; Burack, Jacob A.

2012-01-01

We utilized a hierarchical figures task to determine the default level of perceptual processing and the flexibility of visual processing in a group of high-functioning young adults with autism (n = 12) and a typically developing young adults, matched by chronological age and IQ (n = 12). In one task, participants attended to one level of the…

Differential recruitment of theory of mind brain network across three tasks: An independent component analysis.

PubMed

Thye, Melissa D; Ammons, Carla J; Murdaugh, Donna L; Kana, Rajesh K

2018-07-16

Social neuroscience research has focused on an identified network of brain regions primarily associated with processing Theory of Mind (ToM). However, ToM is a broad cognitive process, which encompasses several sub-processes, such as mental state detection and intentional attribution, and the connectivity of brain regions underlying the broader ToM network in response to paradigms assessing these sub-processes requires further characterization. Standard fMRI analyses which focus only on brain activity cannot capture information about ToM processing at a network level. An alternative method, independent component analysis (ICA), is a data-driven technique used to isolate intrinsic connectivity networks, and this approach provides insight into network-level regional recruitment. In this fMRI study, three complementary, but distinct ToM tasks assessing mental state detection (e.g. RMIE: Reading the Mind in the Eyes; RMIV: Reading the Mind in the Voice) and intentional attribution (Causality task) were each analyzed using ICA in order to separately characterize the recruitment and functional connectivity of core nodes in the ToM network in response to the sub-processes of ToM. Based on visual comparison of the derived networks for each task, the spatiotemporal network patterns were similar between the RMIE and RMIV tasks, which elicited mentalizing about the mental states of others, and these networks differed from the network derived for the Causality task, which elicited mentalizing about goal-directed actions. The medial prefrontal cortex, precuneus, and right inferior frontal gyrus were seen in the components with the highest correlation with the task condition for each of the tasks highlighting the role of these regions in general ToM processing. Using a data-driven approach, the current study captured the differences in task-related brain response to ToM in three distinct ToM paradigms. The findings of this study further elucidate the neural mechanisms associated with mental state detection and causal attribution, which represent possible sub-processes of the complex construct of ToM processing. Published by Elsevier B.V.

Age-related differences in reaction time task performance in young children.

PubMed

Kiselev, Sergey; Espy, Kimberly Andrews; Sheffield, Tiffany

2009-02-01

Performance of reaction time (RT) tasks was investigated in young children and adults to test the hypothesis that age-related differences in processing speed supersede a "global" mechanism and are a function of specific differences in task demands and processing requirements. The sample consisted of 54 4-year-olds, 53 5-year-olds, 59 6-year-olds, and 35 adults from Russia. Using the regression approach pioneered by Brinley and the transformation method proposed by Madden and colleagues and Ridderinkhoff and van der Molen, age-related differences in processing speed differed among RT tasks with varying demands. In particular, RTs differed between children and adults on tasks that required response suppression, discrimination of color or spatial orientation, reversal of contingencies of previously learned stimulus-response rules, and greater stimulus-response complexity. Relative costs of these RT task differences were larger than predicted by the global difference hypothesis except for response suppression. Among young children, age-related differences larger than predicted by the global difference hypothesis were evident when tasks required color or spatial orientation discrimination and stimulus-response rule complexity, but not for response suppression or reversal of stimulus-response contingencies. Process-specific, age-related differences in processing speed that support heterochronicity of brain development during childhood were revealed.

The tendency of unconscious thought toward global processing style.

PubMed

Li, Jiansheng; Wang, Fan; Shen, Mowei; Fan, Gang

2017-08-01

This study explored whether unconscious thought has a tendency to process information globally. In three experiments, a Navon task was used to activate global or local processing styles. Findings showed that in the unconscious-thought groups, those performing the local Navon task presented a poorer decision-making performance when compared to those performing the global Navon task (Experiment 1); participants reported that their judgments were made based on partial attributes (Experiment 2), and evaluated a target individual mainly based on information consistent with stereotypes (Experiment 3). These results showed that when presented with distracter tasks, conscious thought activates local processing, which impairs its ability to process information globally. However, this impairment would not happen if global processing were activated instead. This study provides support to the idea that unconscious thought has a tendency to process information globally. Copyright © 2017 Elsevier Inc. All rights reserved.

Differential age-related decline in conflict-driven task-set shielding from emotional versus non-emotional distracters.

PubMed

Monti, Jim M; Weintraub, Sandra; Egner, Tobias

2010-05-01

While normal aging is associated with a marked decline in cognitive abilities, such as memory and executive functions, recent evidence suggests that control processes involved in regulating responses to emotional stimuli may remain well-preserved in the elderly. However, neither the precise nature of these preserved control processes, nor their domain-specificity with respect to comparable non-emotional control processes, are currently well-established. Here, we tested the hypothesis of domain-specific preservation of emotional control in the elderly by employing two closely matched behavioral tasks that assessed the ability to shield the processing of task-relevant stimulus information from competition by task-irrelevant distracter stimuli that could be either non-emotional or emotional in nature. The efficacy of non-emotional versus emotional task-set shielding, gauged via the 'conflict adaptation effect', was compared between cohorts of healthy young adults, healthy elderly adults, and individuals diagnosed with probable Alzheimer's disease (PRAD), age-matched to the elderly subjects. It was found that, compared to the young adult cohort, the healthy elderly displayed deficits in task-set shielding in the non-emotional but not in the emotional task, whereas PRAD subjects displayed impaired performance in both tasks. These results provide new evidence that healthy aging is associated with a domain-specific preservation of emotional control functions, specifically, the shielding of a current task-set from interference by emotional distracter stimuli. This selective preservation of function supports the notion of partly dissociable affective control mechanisms, and may either reflect different time-courses of degeneration in the neuroanatomical circuits mediating task-set maintenance in the face of non-emotional versus emotional distracters, or a motivational shift towards affective processing in the elderly. 2010 Elsevier Ltd. All rights reserved.

Electrophysiological correlates of preparation and implementation for different types of task shifts.

PubMed

Hsieh, Shulan; Wu, Mengyao

2011-11-14

The ability to flexibly shift between tasks is central to cognitive control, but whether the same brain mechanisms mediate shifting across different tasks is unknown. In this study, we investigated whether variations in stimulus-dimensions or response-mapping might influence task switching in terms of its preparatory processes, as reflected in cue-locked event-related potentials (ERPs), and its implementation processes, as reflected in stimulus-locked ERPs. Participants judged pairs of digits as same or different in one of two conditions. In one condition, the task-relevant stimulus-dimension was either repeated or switched across trials while the response-mapping rule was kept constant. In the other condition, the task-relevant stimulus-dimension was kept constant while the response-mapping rule was repeated or switched across trials. The length of the preparatory interval was manipulated. Data revealed switch-related preparatory ERP components (including N2 and a late slow positivity) that were associated with both types of task shifting and an N400-like negativity that distinguished between the two types. Several switch-related implementation ERP components associated with both types of task shifting were found at posterior sites. Distinct frontal modulations of the N1, P2, and N2 were found to associate with the implementation of the response-mapping shift, whereas a slow positivity was associated with the implementation of the stimulus-dimension shift. Therefore, this study demonstrates that there are shared and distinct processes across different types of task shifting. Finally, because the same transition-cue was used for different task shifts, the distinct processes cannot be explained simply by differences in cue processing. Copyright © 2011 Elsevier B.V. All rights reserved.

Effort in Multitasking: Local and Global Assessment of Effort.

PubMed

Kiesel, Andrea; Dignath, David

2017-01-01

When performing multiple tasks in succession, self-organization of task order might be superior compared to external-controlled task schedules, because self-organization allows optimizing processing modes and thus reduces switch costs, and it increases commitment to task goals. However, self-organization is an additional executive control process that is not required if task order is externally specified and as such it is considered as time-consuming and effortful. To compare self-organized and externally controlled task scheduling, we suggest assessing global subjective and objectives measures of effort in addition to local performance measures. In our new experimental approach, we combined characteristics of dual tasking settings and task switching settings and compared local and global measures of effort in a condition with free choice of task sequence and a condition with cued task sequence. In a multi-tasking environment, participants chose the task order while the task requirement of the not-yet-performed task remained the same. This task preview allowed participants to work on the previously non-chosen items in parallel and resulted in faster responses and fewer errors in task switch trials than in task repetition trials. The free-choice group profited more from this task preview than the cued group when considering local performance measures. Nevertheless, the free-choice group invested more effort than the cued group when considering global measures. Thus, self-organization in task scheduling seems to be effortful even in conditions in which it is beneficiary for task processing. In a second experiment, we reduced the possibility of task preview for the not-yet-performed tasks in order to hinder efficient self-organization. Here neither local nor global measures revealed substantial differences between the free-choice and a cued task sequence condition. Based on the results of both experiments, we suggest that global assessment of effort in addition to local performance measures might be a useful tool for multitasking research.

Intentional and automatic numerical processing as predictors of mathematical abilities in primary school children

PubMed Central

Pina, Violeta; Castillo, Alejandro; Cohen Kadosh, Roi; Fuentes, Luis J.

2015-01-01

Previous studies have suggested that numerical processing relates to mathematical performance, but it seems that such relationship is more evident for intentional than for automatic numerical processing. In the present study we assessed the relationship between the two types of numerical processing and specific mathematical abilities in a sample of 109 children in grades 1–6. Participants were tested in an ample range of mathematical tests and also performed both a numerical and a size comparison task. The results showed that numerical processing related to mathematical performance only when inhibitory control was involved in the comparison tasks. Concretely, we found that intentional numerical processing, as indexed by the numerical distance effect in the numerical comparison task, was related to mathematical reasoning skills only when the task-irrelevant dimension (the physical size) was incongruent; whereas automatic numerical processing, indexed by the congruency effect in the size comparison task, was related to mathematical calculation skills only when digits were separated by small distance. The observed double dissociation highlights the relevance of both intentional and automatic numerical processing in mathematical skills, but when inhibitory control is also involved. PMID:25873909

LSSA large area silicon sheet task continuous Czochralski process development

NASA Technical Reports Server (NTRS)

Rea, S. N.

1978-01-01

A Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a premelter to provide molten silicon flow into the primary crucible. The basic furnace is operational and several trial crystals were grown in the batch mode. Numerous premelter configurations were tested both in laboratory-scale equipment as well as in the actual furnace. The best arrangement tested to date is a vertical, cylindrical graphite heater containing small fused silicon test tube liner in which the incoming silicon is melted and flows into the primary crucible. Economic modeling of the continuous Czochralski process indicates that for 10 cm diameter crystal, 100 kg furnace runs of four or five crystals each are near-optimal. Costs tend to asymptote at the 100 kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $20/sq m exclusive of polysilicon and slicing was obtained.

Silicon on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Pickering, C.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

1979-01-01

The technical and economic feasibility of producing solar cell quality sheet silicon was investigated. It was hoped this could be done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Work was directed towards the solution of unique cell processing/design problems encountered with the silicon-ceramic (SOC) material due to its intimate contact with the ceramic substrate. Significant progress was demonstrated in the following areas; (1) the continuous coater succeeded in producing small-area coatings exhibiting unidirectional solidification and substatial grain size; (2) dip coater succeeded in producing thick (more than 500 micron) dendritic layers at coating speeds of 0.2-0.3 cm/sec; and (3) a standard for producing total area SOC solar cells using slotted ceramic substrates was developed.

Applications of artificial neural networks (ANNs) in food science.

PubMed

Huang, Yiqun; Kangas, Lars J; Rasco, Barbara A

2007-01-01

Artificial neural networks (ANNs) have been applied in almost every aspect of food science over the past two decades, although most applications are in the development stage. ANNs are useful tools for food safety and quality analyses, which include modeling of microbial growth and from this predicting food safety, interpreting spectroscopic data, and predicting physical, chemical, functional and sensory properties of various food products during processing and distribution. ANNs hold a great deal of promise for modeling complex tasks in process control and simulation and in applications of machine perception including machine vision and electronic nose for food safety and quality control. This review discusses the basic theory of the ANN technology and its applications in food science, providing food scientists and the research community an overview of the current research and future trend of the applications of ANN technology in the field.

Evaluation of Alternative Splicing Regulators As Targets For Selective Therapy of Triple Negative (Basal) Breast Carcinoma

DTIC Science & Technology

2016-10-01

KHDRBS3 and SRSF12 on tumor progression and metastasis (Task1). We analyzed the effect of KHDRBS3 depletion on the growth and migration properties of the...tumor growth during the second year of this project. Continued analysis of the splicing factor expression in primary tumor samples further supports...depletion on tumor initiation, growth and metastasis. Keywords Pre-mRNA splicing, breast cancer, KHDRBS3, SRPK1, SRSF12, metastasis

Regulation of the Mevalonate Pathway for the Prevention of Breast Cancer

DTIC Science & Technology

2002-08-01

eicosapentaenoic acid (EPA) on growth of MCF-7 cells. In Task 4 (new), we determined that mevalonate promotes the growth of mammary tumors in nude mice, and...serum medium (2% fetal bovine serum) was used to support MCF-7 growth during test treatments. The effects of the n-3 PUFAs eicosapentaenoic acid (EPA...mammary carcinogenesis by n-3 polyunsaturated fatty acids (PUFAs) can be accounted for by their inhibitory effect on the cholesterol biosynthesis

Intact and impaired conceptual memory processes in amnesia.

PubMed

Keane, M M; Gabrieli, J D; Monti, L A; Fleischman, D A; Cantor, J M; Noland, J S

1997-01-01

To examine the status of conceptual memory processes in amnesia, a conceptual memory task with implicit or explicit task instructions was given to amnesic and control groups. After studying a list of category exemplars, participants saw category labels and were asked to generate as many exemplars as possible (an implicit memory task) or to generate exemplars that had been in the prior study list (an explicit memory task). After incidental deep or shallow encoding of exemplars, amnesic patients showed normal implicit memory performance (priming), a normal levels-of-processing effect on priming, and impaired explicit memory performance. After intentional encoding of exemplars, amnesic patients showed impaired implicit and explicit memory performance. Results suggest that although amnesic patients can show impairments on implicit and explicit conceptual memory tasks, their deficit does not generalize to all conceptual memory tasks.

The Correlation among Neural Dynamic Processing of Conflict Control, Testosterone and Cortisol Levels in 10-Year-Old Children

PubMed Central

Shangguan, Fangfang; Liu, Tongran; Liu, Xiuying; Shi, Jiannong

2017-01-01

Cognitive control is related to goal-directed self-regulation abilities, which is fundamental for human development. Conflict control includes the neural processes of conflict monitoring and conflict resolution. Testosterone and cortisol are essential hormones for the development of cognitive functions. However, there are no studies that have investigated the correlation of these two hormones with conflict control in preadolescents. In this study, we aimed to explore whether testosterone, cortisol, and testosterone/cortisol ratio worked differently for preadolescent’s conflict control processes in varied conflict control tasks. Thirty-two 10-year-old children (16 boys and 16 girls) were enrolled. They were instructed to accomplish three conflict control tasks with different conflict dimensions, including the Flanker, Simon, and Stroop tasks, and electrophysiological signals were recorded. Salivary samples were collected from each child. The testosterone and cortisol levels were determined by enzyme-linked immunosorbent assay. The electrophysiological results showed that the incongruent trials induced greater N2/N450 and P3/SP responses than the congruent trials during neural processes of conflict monitoring and conflict resolution in the Flanker and Stroop tasks. The hormonal findings showed that (1) the testosterone/cortisol ratio was correlated with conflict control accuracy and conflict resolution in the Flanker task; (2) the testosterone level was associated with conflict control performance and neural processing of conflict resolution in the Stroop task; (3) the cortisol level was correlated with conflict control performance and neural processing of conflict monitoring in the Simon task. In conclusion, in 10-year-old children, the fewer processes a task needs, the more likely there is an association between the T/C ratios and the behavioral and brain response, and the dual-hormone effects on conflict resolution may be testosterone-driven in the Stroop and Flanker tasks. PMID:28690571

Combining Temporal and Spectral Information with Spatial Mapping to Identify Differences between Phonological and Semantic Networks: A Magnetoencephalographic Approach.

PubMed

McNab, Fiona; Hillebrand, Arjan; Swithenby, Stephen J; Rippon, Gina

2012-01-01

Early, lesion-based models of language processing suggested that semantic and phonological processes are associated with distinct temporal and parietal regions respectively, with frontal areas more indirectly involved. Contemporary spatial brain mapping techniques have not supported such clear-cut segregation, with strong evidence of activation in left temporal areas by both processes and disputed evidence of involvement of frontal areas in both processes. We suggest that combining spatial information with temporal and spectral data may allow a closer scrutiny of the differential involvement of closely overlapping cortical areas in language processing. Using beamforming techniques to analyze magnetoencephalography data, we localized the neuronal substrates underlying primed responses to nouns requiring either phonological or semantic processing, and examined the associated measures of time and frequency in those areas where activation was common to both tasks. Power changes in the beta (14-30 Hz) and gamma (30-50 Hz) frequency bands were analyzed in pre-selected time windows of 350-550 and 500-700 ms In left temporal regions, both tasks elicited power changes in the same time window (350-550 ms), but with different spectral characteristics, low beta (14-20 Hz) for the phonological task and high beta (20-30 Hz) for the semantic task. In frontal areas (BA10), both tasks elicited power changes in the gamma band (30-50 Hz), but in different time windows, 500-700 ms for the phonological task and 350-550 ms for the semantic task. In the left inferior parietal area (BA40), both tasks elicited changes in the 20-30 Hz beta frequency band but in different time windows, 350-550 ms for the phonological task and 500-700 ms for the semantic task. Our findings suggest that, where spatial measures may indicate overlapping areas of involvement, additional beamforming techniques can demonstrate differential activation in time and frequency domains.

The Inner Processes Underlying Vocational Development.

ERIC Educational Resources Information Center

Bujold, Charles E.; And Others

Educational and occupational choices may be considered, from a developmental point of view, as long-term problems whose solutions imply a number of tasks. These tasks sequentially might be called exploration, crystallization, specification, and implementation. What are the processes involved in these tasks? What are the abilities which make…

Supportive behaviors in adolescent romantic relationships moderate adrenocortical attunement.

PubMed

Ha, Thao; Yeung, Ellen Wanheung; Rogers, Adam A; Poulsen, Franklin O; Kornienko, Olga; Granger, Douglas A

2016-12-01

This study investigated dyadic adrenocortical attunement within adolescent romantic relationships. An ethnically diverse sample (42% Latino) of adolescent heterosexual dating couples (N=91 dyads, Mage=16.5 years, SD=0.99) donated eight saliva samples (later assayed for cortisol) over the course of a 3-h laboratory session. Supportive behaviors were coded during a conflict and jealousy interaction task from video recordings, and participants completed pre-and-post task questionnaires. Parallel process latent growth models revealed a strong positive association between the couples' cortisol intercept, indicating that couples show attunement in initial levels of cortisol. Further, observed supportive behavior moderated the strength of the association between dyadic cortisol slopes. The results imply that low levels of supportive behavior predicted stronger adrenocortical attunement in the change in cortisol levels over time between adolescent romantic partners. These findings indicate that even early romantic relationships exhibit coordination of physiological activity. Findings raise the possibility that adrenocortical attunement may be a dyadic pathway through which the proximal social context of early romantic relationships is translated into risk or resilience in health and behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Model-based Framework for Risk Assessment in Human-Computer Controlled Systems

NASA Technical Reports Server (NTRS)

Hatanaka, Iwao

2000-01-01

The rapid growth of computer technology and innovation has played a significant role in the rise of computer automation of human tasks in modem production systems across all industries. Although the rationale for automation has been to eliminate "human error" or to relieve humans from manual repetitive tasks, various computer-related hazards and accidents have emerged as a direct result of increased system complexity attributed to computer automation. The risk assessment techniques utilized for electromechanical systems are not suitable for today's software-intensive systems or complex human-computer controlled systems. This thesis will propose a new systemic model-based framework for analyzing risk in safety-critical systems where both computers and humans are controlling safety-critical functions. A new systems accident model will be developed based upon modem systems theory and human cognitive processes to better characterize system accidents, the role of human operators, and the influence of software in its direct control of significant system functions. Better risk assessments will then be achievable through the application of this new framework to complex human-computer controlled systems.

Safety Metrics for Human-Computer Controlled Systems

NASA Technical Reports Server (NTRS)

Leveson, Nancy G; Hatanaka, Iwao

2000-01-01

The rapid growth of computer technology and innovation has played a significant role in the rise of computer automation of human tasks in modem production systems across all industries. Although the rationale for automation has been to eliminate "human error" or to relieve humans from manual repetitive tasks, various computer-related hazards and accidents have emerged as a direct result of increased system complexity attributed to computer automation. The risk assessment techniques utilized for electromechanical systems are not suitable for today's software-intensive systems or complex human-computer controlled systems.This thesis will propose a new systemic model-based framework for analyzing risk in safety-critical systems where both computers and humans are controlling safety-critical functions. A new systems accident model will be developed based upon modem systems theory and human cognitive processes to better characterize system accidents, the role of human operators, and the influence of software in its direct control of significant system functions Better risk assessments will then be achievable through the application of this new framework to complex human-computer controlled systems.

How Will America Grow? A Citizen Guide to Land-Use Planning.

ERIC Educational Resources Information Center

Citizens Advisory Committee on Environmental Quality.

Citizens are encouraged to learn about and become involved in land use and growth issues in their communities. Intended as a follow-up of an earlier report by the Committee's Task Force on Land Use and Urban Growth which outlined philosophical, legal, and policy aspects of land-use planning, the document suggests planning guidelines for citizen…

Engineering development of selective agglomeration: Task 5, Bench- scale process testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-09-01

Under the overall objectives of DOE Contract ``Engineering Development of Selective Agglomeration,`` there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

Engineering development of selective agglomeration: Task 5, Bench- scale process testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-09-01

Under the overall objectives of DOE Contract Engineering Development of Selective Agglomeration,'' there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

Stimulus-response compatibility and psychological refractory period effects: implications for response selection

NASA Technical Reports Server (NTRS)

Lien, Mei-Ching; Proctor, Robert W.

2002-01-01

The purpose of this paper was to provide insight into the nature of response selection by reviewing the literature on stimulus-response compatibility (SRC) effects and the psychological refractory period (PRP) effect individually and jointly. The empirical findings and theoretical explanations of SRC effects that have been studied within a single-task context suggest that there are two response-selection routes-automatic activation and intentional translation. In contrast, all major PRP models reviewed in this paper have treated response selection as a single processing stage. In particular, the response-selection bottleneck (RSB) model assumes that the processing of Task 1 and Task 2 comprises two separate streams and that the PRP effect is due to a bottleneck located at response selection. Yet, considerable evidence from studies of SRC in the PRP paradigm shows that the processing of the two tasks is more interactive than is suggested by the RSB model and by most other models of the PRP effect. The major implication drawn from the studies of SRC effects in the PRP context is that response activation is a distinct process from final response selection. Response activation is based on both long-term and short-term task-defined S-R associations and occurs automatically and in parallel for the two tasks. The final response selection is an intentional act required even for highly compatible and practiced tasks and is restricted to processing one task at a time. Investigations of SRC effects and response-selection variables in dual-task contexts should be conducted more systematically because they provide significant insight into the nature of response-selection mechanisms.

Dyslexic Children Show Atypical Cerebellar Activation and Cerebro-Cerebellar Functional Connectivity in Orthographic and Phonological Processing.

PubMed

Feng, Xiaoxia; Li, Le; Zhang, Manli; Yang, Xiujie; Tian, Mengyu; Xie, Weiyi; Lu, Yao; Liu, Li; Bélanger, Nathalie N; Meng, Xiangzhi; Ding, Guosheng

2017-04-01

Previous neuroimaging studies have found atypical cerebellar activation in individuals with dyslexia in either motor-related tasks or language tasks. However, studies investigating atypical cerebellar activation in individuals with dyslexia have mostly used tasks tapping phonological processing. A question that is yet unanswered is whether the cerebellum in individuals with dyslexia functions properly during orthographic processing of words, as growing evidence shows that the cerebellum is also involved in visual and spatial processing. Here, we investigated cerebellar activation and cerebro-cerebellar functional connectivity during word processing in dyslexic readers and typically developing readers using tasks that tap orthographic and phonological codes. In children with dyslexia, we observed an abnormally higher engagement of the bilateral cerebellum for the orthographic task, which was negatively correlated with literacy measures. The greater the reading impairment was for young dyslexic readers, the stronger the cerebellar activation was. This suggests a compensatory role of the cerebellum in reading for children with dyslexia. In addition, a tendency for higher cerebellar activation in dyslexic readers was found in the phonological task. Moreover, the functional connectivity was stronger for dyslexic readers relative to typically developing readers between the lobule VI of the right cerebellum and the left fusiform gyrus during the orthographic task and between the lobule VI of the left cerebellum and the left supramarginal gyrus during the phonological task. This pattern of results suggests that the cerebellum compensates for reading impairment through the connections with specific brain regions responsible for the ongoing reading task. These findings enhance our understanding of the cerebellum's involvement in reading and reading impairment.

Exploring the repetition bias in voluntary task switching.

PubMed

Mittelstädt, Victor; Dignath, David; Schmidt-Ott, Magdalena; Kiesel, Andrea

2018-01-01

In the voluntary task-switching paradigm, participants are required to randomly select tasks. We reasoned that the consistent finding of a repetition bias (i.e., participants repeat tasks more often than expected by chance) reflects reasonable adaptive task selection behavior to balance the goal of random task selection with the goals to minimize the time and effort for task performance. We conducted two experiments in which participants were provided with variable amount of preview for the non-chosen task stimuli (i.e., potential switch stimuli). We assumed that switch stimuli would initiate some pre-processing resulting in improved performance in switch trials. Results showed that reduced switch costs due to extra-preview in advance of each trial were accompanied by more task switches. This finding is in line with the characteristics of rational adaptive behavior. However, participants were not biased to switch tasks more often than chance despite large switch benefits. We suggest that participants might avoid effortful additional control processes that modulate the effects of preview on task performance and task choice.

Estimating the executive demands of a one-back choice reaction time task by means of the selective interference paradigm.

PubMed

Szmalec, Arnaud; Vandierendonck, André

2007-08-01

The present study proposes a new executive task, the one-back choice reaction time (RT) task, and implements the selective interference paradigm to estimate the executive demands of the processing components involved in this task. Based on the similarities between a one-back choice RT task and the n-back updating task, it was hypothesized that one-back delaying of a choice reaction involves executive control. In three experiments, framed within Baddeley's (1986) working-memory model, a one-back choice RT task, a choice RT task, articulatory suppression, and matrix tapping were performed concurrently with primary tasks involving verbal, visuospatial, and executive processing. The results demonstrate that one-back delaying of a choice reaction interferes with tasks requiring executive control, while the potential interference at the level of the verbal or visuospatial working memory slave systems remains minimal.

Large-area sheet task advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D. L.; Schruben, J.

1982-01-01

Thermal models were developed that accurately predict the thermally generated stresses in the web crystal which, if too high, cause the crystal to degenerate. The application of the modeling results to the design of low-stress experimental growth configurations will allow the growth of wider web crystals at higher growth velocities. A new experimental web growth machine was constructed. This facility includes all the features necessary for carrying out growth experiments under steady thermal conditions. Programmed growth initiation was developed to give reproducible crystal starts. Width control permits the growth of long ribbons at constant width. Melt level is controlled to 0.1 mm or better. Thus, the capability exists to grow long web crystals of constant width and thickness with little operator intervention, and web growth experiments can now be performed with growth variables controlled to a degree not previously possible.

Stress studies in EFG

NASA Technical Reports Server (NTRS)

1982-01-01

A program to study stress generation mechanisms in silicon sheet growth was started. The purpose of the research is to define post-growth temperature profiles for the sheet that can minimize its stress during growth at high speeds, e.g., greater than 3 cm/min. The initial tasks described concern work in progress toward the development of computing capabilities to (1) model stress-temperature relationships in steady-state ribbon growth, and (2) provide a means to calculate realistic temperature fields in ribbon, given growth system component temperatures as boundary conditions. If it is determined that low stress configurations can be achieved, the modeling is to be tested experimentally by constructing low-stress growth systems for EFG silicon ribbon.

Attention effects on the processing of task-relevant and task-irrelevant speech sounds and letters

PubMed Central

Mittag, Maria; Inauri, Karina; Huovilainen, Tatu; Leminen, Miika; Salo, Emma; Rinne, Teemu; Kujala, Teija; Alho, Kimmo

2013-01-01

We used event-related brain potentials (ERPs) to study effects of selective attention on the processing of attended and unattended spoken syllables and letters. Participants were presented with syllables randomly occurring in the left or right ear and spoken by different voices and with a concurrent foveal stream of consonant letters written in darker or lighter fonts. During auditory phonological (AP) and non-phonological tasks, they responded to syllables in a designated ear starting with a vowel and spoken by female voices, respectively. These syllables occurred infrequently among standard syllables starting with a consonant and spoken by male voices. During visual phonological and non-phonological tasks, they responded to consonant letters with names starting with a vowel and to letters written in dark fonts, respectively. These letters occurred infrequently among standard letters with names starting with a consonant and written in light fonts. To examine genuine effects of attention and task on ERPs not overlapped by ERPs associated with target processing or deviance detection, these effects were studied only in ERPs to auditory and visual standards. During selective listening to syllables in a designated ear, ERPs to the attended syllables were negatively displaced during both phonological and non-phonological auditory tasks. Selective attention to letters elicited an early negative displacement and a subsequent positive displacement (Pd) of ERPs to attended letters being larger during the visual phonological than non-phonological task suggesting a higher demand for attention during the visual phonological task. Active suppression of unattended speech during the AP and non-phonological tasks and during the visual phonological tasks was suggested by a rejection positivity (RP) to unattended syllables. We also found evidence for suppression of the processing of task-irrelevant visual stimuli in visual ERPs during auditory tasks involving left-ear syllables. PMID:24348324

Using task analysis to improve the requirements elicitation in health information system.

PubMed

Teixeira, Leonor; Ferreira, Carlos; Santos, Beatriz Sousa

2007-01-01

This paper describes the application of task analysis within the design process of a Web-based information system for managing clinical information in hemophilia care, in order to improve the requirements elicitation and, consequently, to validate the domain model obtained in a previous phase of the design process (system analysis). The use of task analysis in this case proved to be a practical and efficient way to improve the requirements engineering process by involving users in the design process.

Elevated temperature crack growth

NASA Technical Reports Server (NTRS)

Kim, K. S.; Vanstone, R. H.

1992-01-01

The purpose of this program was to extend the work performed in the base program (CR 182247) into the regime of time-dependent crack growth under isothermal and thermal mechanical fatigue (TMF) loading, where creep deformation also influences the crack growth behavior. The investigation was performed in a two-year, six-task, combined experimental and analytical program. The path-independent integrals for application to time-dependent crack growth were critically reviewed. The crack growth was simulated using a finite element method. The path-independent integrals were computed from the results of finite-element analyses. The ability of these integrals to correlate experimental crack growth data were evaluated under various loading and temperature conditions. The results indicate that some of these integrals are viable parameters for crack growth prediction at elevated temperatures.

Human transinformation rates during one-to-four axis tracking with a concurrent audio task

NASA Technical Reports Server (NTRS)

Baty, D. L.

1972-01-01

The information processing rates of six subjects performing one-, two-, three-, and four-axis compensatory tracking tasks, with and without a concurrent four-choice auditory task were determined. The purpose was to obtain further evidence concerning the nature of an hypothesized ceiling on human transinformation rates. Interference was found among tasks, but the evidence concerning a ceiling on information processing rates was inconclusive.

What Comes First? How Selective Attentional Processes Regulate the Activation of a Motor Routine in a Manual Search Task

ERIC Educational Resources Information Center

Riviere, James; Falaise, Aurelie

2011-01-01

An intriguing error has been observed in toddlers presented with a 3-location search task involving invisible displacements of an object, namely, the C-not-B task. In 3 experiments, the authors investigated the dynamics of the attentional focus process that is suspected to be involved in this task. In Experiment 1, 2.5-year-old children were…

Recognition and reading aloud of kana and kanji word: an fMRI study.

PubMed

Ino, Tadashi; Nakai, Ryusuke; Azuma, Takashi; Kimura, Toru; Fukuyama, Hidenao

2009-03-16

It has been proposed that different brain regions are recruited for processing two Japanese writing systems, namely, kanji (morphograms) and kana (syllabograms). However, this difference may depend upon what type of word was used and also on what type of task was performed. Using fMRI, we investigated brain activation for processing kanji and kana words with similar high familiarity in two tasks: word recognition and reading aloud. During both tasks, words and non-words were presented side by side, and the subjects were required to press a button corresponding to the real word in the word recognition task and were required to read aloud the real word in the reading aloud task. Brain activations were similar between kanji and kana during reading aloud task, whereas during word recognition task in which accurate identification and selection were required, kanji relative to kana activated regions of bilateral frontal, parietal and occipitotemporal cortices, all of which were related mainly to visual word-form analysis and visuospatial attention. Concerning the difference of brain activity between two tasks, differential activation was found only in the regions associated with task-specific sensorimotor processing for kana, whereas visuospatial attention network also showed greater activation during word recognition task than during reading aloud task for kanji. We conclude that the differences in brain activation between kanji and kana depend on the interaction between the script characteristics and the task demands.

Training attentional control in older adults

PubMed Central

MacKay-Brandt, Anna

2013-01-01

Recent research has demonstrated benefits for older adults from training attentional control using a variable priority strategy, but the construct validity of the training task and the degree to which benefits of training transfer to other contexts are unclear. The goal of this study was to characterize baseline performance on the training task in a sample of 105 healthy older adults and to test for transfer of training in a subset (n = 21). Training gains after 5 days and extent of transfer was compared to another subset (n = 20) that served as a control group. Baseline performance on the training task was characterized by a two-factor model of working memory and processing speed. Processing speed correlated with the training task. Training gains in speed and accuracy were reliable and robust (ps <.001, η2 = .57 to .90). Transfer to an analogous task was observed (ps <.05, η2 = .10 to .17). The beneficial effect of training did not translate to improved performance on related measures of processing speed. This study highlights the robust effect of training and transfer to a similar context using a variable priority training task. Although processing speed is an important aspect of the training task, training benefit is either related to an untested aspect of the training task or transfer of training is limited to the training context. PMID:21728889

Effects of cue focality on the neural mechanisms of prospective memory: A meta-analysis of neuroimaging studies.

PubMed

Cona, Giorgia; Bisiacchi, Patrizia Silvia; Sartori, Giuseppe; Scarpazza, Cristina

2016-05-17

Remembering to execute pre-defined intentions at the appropriate time in the future is typically referred to as Prospective Memory (PM). Studies of PM showed that distinct cognitive processes underlie the execution of delayed intentions depending on whether the cue associated with such intentions is focal to ongoing activity processing or not (i.e., cue focality). The present activation likelihood estimation (ALE) meta-analysis revealed several differences in brain activity as a function of focality of the PM cue. The retrieval of intention is supported mainly by left anterior prefrontal cortex (Brodmann Area, BA 10) in nonfocal tasks, and by cerebellum and ventral parietal regions in focal tasks. Furthermore, the precuneus showed increased activation during the maintenance phase of intentions compared to the retrieval phase in nonfocal tasks, whereas the inferior parietal lobule showed increased activation during the retrieval of intention compared to maintenance phase in the focal tasks. Finally, the retrieval of intention relies more on the activity in anterior cingulate cortex for nonfocal tasks, and on posterior cingulate cortex for focal tasks. Such focality-related pattern of activations suggests that prospective remembering is mediated mainly by top-down and stimulus-independent processes in nonfocal tasks, whereas by more automatic, bottom-up, processes in focal tasks.

Effects of cue focality on the neural mechanisms of prospective memory: A meta-analysis of neuroimaging studies

PubMed Central

Cona, Giorgia; Bisiacchi, Patrizia Silvia; Sartori, Giuseppe; Scarpazza, Cristina

2016-01-01

Remembering to execute pre-defined intentions at the appropriate time in the future is typically referred to as Prospective Memory (PM). Studies of PM showed that distinct cognitive processes underlie the execution of delayed intentions depending on whether the cue associated with such intentions is focal to ongoing activity processing or not (i.e., cue focality). The present activation likelihood estimation (ALE) meta-analysis revealed several differences in brain activity as a function of focality of the PM cue. The retrieval of intention is supported mainly by left anterior prefrontal cortex (Brodmann Area, BA 10) in nonfocal tasks, and by cerebellum and ventral parietal regions in focal tasks. Furthermore, the precuneus showed increased activation during the maintenance phase of intentions compared to the retrieval phase in nonfocal tasks, whereas the inferior parietal lobule showed increased activation during the retrieval of intention compared to maintenance phase in the focal tasks. Finally, the retrieval of intention relies more on the activity in anterior cingulate cortex for nonfocal tasks, and on posterior cingulate cortex for focal tasks. Such focality-related pattern of activations suggests that prospective remembering is mediated mainly by top-down and stimulus-independent processes in nonfocal tasks, whereas by more automatic, bottom-up, processes in focal tasks. PMID:27185531

Reward sensitivity modulates brain activity in the prefrontal cortex, ACC and striatum during task switching.

PubMed

Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

2015-01-01

Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies.

Reward Sensitivity Modulates Brain Activity in the Prefrontal Cortex, ACC and Striatum during Task Switching

PubMed Central

Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C.; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

2015-01-01

Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies. PMID:25875640

Executive functioning and processing speed in age-related differences in memory: contribution of a coding task.

PubMed

Baudouin, Alexia; Clarys, David; Vanneste, Sandrine; Isingrini, Michel

2009-12-01

The aim of the present study was to examine executive dysfunctioning and decreased processing speed as potential mediators of age-related differences in episodic memory. We compared the performances of young and elderly adults in a free-recall task. Participants were also given tests to measure executive functions and perceptual processing speed and a coding task (the Digit Symbol Substitution Test, DSST). More precisely, we tested the hypothesis that executive functions would mediate the age-related differences observed in the free-recall task better than perceptual speed. We also tested the assumption that a coding task, assumed to involve both executive processes and perceptual speed, would be the best mediator of age-related differences in memory. Findings first confirmed that the DSST combines executive processes and perceptual speed. Secondly, they showed that executive functions are a significant mediator of age-related differences in memory, and that DSST performance is the best predictor.

A resource for assessing information processing in the developing brain using EEG and eye tracking

PubMed Central

Langer, Nicolas; Ho, Erica J.; Alexander, Lindsay M.; Xu, Helen Y.; Jozanovic, Renee K.; Henin, Simon; Petroni, Agustin; Cohen, Samantha; Marcelle, Enitan T.; Parra, Lucas C.; Milham, Michael P.; Kelly, Simon P.

2017-01-01

We present a dataset combining electrophysiology and eye tracking intended as a resource for the investigation of information processing in the developing brain. The dataset includes high-density task-based and task-free EEG, eye tracking, and cognitive and behavioral data collected from 126 individuals (ages: 6–44). The task battery spans both the simple/complex and passive/active dimensions to cover a range of approaches prevalent in modern cognitive neuroscience. The active task paradigms facilitate principled deconstruction of core components of task performance in the developing brain, whereas the passive paradigms permit the examination of intrinsic functional network activity during varying amounts of external stimulation. Alongside these neurophysiological data, we include an abbreviated cognitive test battery and questionnaire-based measures of psychiatric functioning. We hope that this dataset will lead to the development of novel assays of neural processes fundamental to information processing, which can be used to index healthy brain development as well as detect pathologic processes. PMID:28398357

A resource for assessing information processing in the developing brain using EEG and eye tracking.

PubMed

Langer, Nicolas; Ho, Erica J; Alexander, Lindsay M; Xu, Helen Y; Jozanovic, Renee K; Henin, Simon; Petroni, Agustin; Cohen, Samantha; Marcelle, Enitan T; Parra, Lucas C; Milham, Michael P; Kelly, Simon P

2017-04-11

We present a dataset combining electrophysiology and eye tracking intended as a resource for the investigation of information processing in the developing brain. The dataset includes high-density task-based and task-free EEG, eye tracking, and cognitive and behavioral data collected from 126 individuals (ages: 6-44). The task battery spans both the simple/complex and passive/active dimensions to cover a range of approaches prevalent in modern cognitive neuroscience. The active task paradigms facilitate principled deconstruction of core components of task performance in the developing brain, whereas the passive paradigms permit the examination of intrinsic functional network activity during varying amounts of external stimulation. Alongside these neurophysiological data, we include an abbreviated cognitive test battery and questionnaire-based measures of psychiatric functioning. We hope that this dataset will lead to the development of novel assays of neural processes fundamental to information processing, which can be used to index healthy brain development as well as detect pathologic processes.

Interference among the Processing of Facial Emotion, Face Race, and Face Gender.

PubMed

Li, Yongna; Tse, Chi-Shing

2016-01-01

People can process multiple dimensions of facial properties simultaneously. Facial processing models are based on the processing of facial properties. The current study examined the processing of facial emotion, face race, and face gender using categorization tasks. The same set of Chinese, White and Black faces, each posing a neutral, happy or angry expression, was used in three experiments. Facial emotion interacted with face race in all the tasks. The interaction of face race and face gender was found in the race and gender categorization tasks, whereas the interaction of facial emotion and face gender was significant in the emotion and gender categorization tasks. These results provided evidence for a symmetric interaction between variant facial properties (emotion) and invariant facial properties (race and gender).

Interference among the Processing of Facial Emotion, Face Race, and Face Gender

PubMed Central

Li, Yongna; Tse, Chi-Shing

2016-01-01

People can process multiple dimensions of facial properties simultaneously. Facial processing models are based on the processing of facial properties. The current study examined the processing of facial emotion, face race, and face gender using categorization tasks. The same set of Chinese, White and Black faces, each posing a neutral, happy or angry expression, was used in three experiments. Facial emotion interacted with face race in all the tasks. The interaction of face race and face gender was found in the race and gender categorization tasks, whereas the interaction of facial emotion and face gender was significant in the emotion and gender categorization tasks. These results provided evidence for a symmetric interaction between variant facial properties (emotion) and invariant facial properties (race and gender). PMID:27840621

Research on growth factors in periodontology.

PubMed

Smith, Patricio C; Martínez, Constanza; Cáceres, Mónica; Martínez, Jorge

2015-02-01

Growth factors play critical roles in periodontal repair through the regulation of cell behavior. Many of the cell responses regulated by these proteins include cell adhesion, migration, proliferation and differentiation. Periodontal regeneration involves an organized response of different cells, tissues and growth factors implicated in the coordination of these events. However, periodontal tissue reconstruction is an extremely difficult task. Multiple studies have been performed to understand the specific role of growth factors in periodontal wound healing. In the present review we analyze the evidence that supports the roles of growth factors in periodontal wound healing and regeneration. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Large area sheet task. Advanced dendritic web growth development. [silicon films

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Frantti, E.; Schruben, J.

1981-01-01

The development of a silicon dendritic web growth machine is discussed. Several refinements to the sensing and control equipment for melt replenishment during web growth are described and several areas for cost reduction in the components of the prototype automated web growth furnace are identified. A circuit designed to eliminate the sensitivity of the detector signal to the intensity of the reflected laser beam used to measure melt level is also described. A variable speed motor for the silicon feeder is discussed which allows pellet feeding to be accomplished at a rate programmed to match exactly the silicon removed by web growth.

Methods for Conducting Cognitive Task Analysis for a Decision Making Task.

DTIC Science & Technology

1996-01-01

Cognitive task analysis (CTA) improves traditional task analysis procedures by analyzing the thought processes of performers while they complete a...for using these methods to conduct a CTA for domains which involve critical decision making tasks in naturalistic settings. The cognitive task analysis methods

Modeling Cognitive Strategies during Complex Task Performing Process

ERIC Educational Resources Information Center

Mazman, Sacide Guzin; Altun, Arif

2012-01-01

The purpose of this study is to examine individuals' computer based complex task performing processes and strategies in order to determine the reasons of failure by cognitive task analysis method and cued retrospective think aloud with eye movement data. Study group was five senior students from Computer Education and Instructional Technologies…

Methodology in the assessment of complex performance : the effects of signal rate on monitoring a static process.

DOT National Transportation Integrated Search

1969-08-01

This study concerned the rate of presentation of stimuli on a task involving the monitoring of a static process of the kind represented by aircraft warning light indicators. The task was performed concurrently with various combinations of tasks requi...

An Integrated Process Model of Stereotype Threat Effects on Performance

PubMed Central

Johns, Michael; Forbes, Chad

2008-01-01

Research showing that activation of negative stereotypes can impair the performance of stigmatized individuals on a wide variety of tasks has proliferated. However, a complete understanding of the processes underlying these stereotype threat effects on behavior is still lacking. The authors examine stereotype threat in the context of research on stress arousal, vigilance, working memory, and self-regulation to develop a process model of how negative stereotypes impair performance on cognitive and social tasks that require controlled processing, as well as sensorimotor tasks that require automatic processing. The authors argue that stereotype threat disrupts performance via 3 distinct, yet interrelated, mechanisms: (a) a physiological stress response that directly impairs prefrontal processing, (b) a tendency to actively monitor performance, and (c) efforts to suppress negative thoughts and emotions in the service of self-regulation. These mechanisms combine to consume executive resources needed to perform well on cognitive and social tasks. The active monitoring mechanism disrupts performance on sensorimotor tasks directly. Empirical evidence for these assertions is reviewed, and implications for interventions designed to alleviate stereotype threat are discussed. PMID:18426293

Energy Supply- Production of Fuel from Agricultural and Animal Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabriel Miller

2009-03-25

The Society for Energy and Environmental Research (SEER) was funded in March 2004 by the Department of Energy, under grant DE-FG-36-04GO14268, to produce a study, and oversee construction and implementation, for the thermo-chemical production of fuel from agricultural and animal waste. The grant focuses on the Changing World Technologies (CWT) of West Hempstead, NY, thermal conversion process (TCP), which converts animal residues and industrial food processing biproducts into fuels, and as an additional product, fertilizers. A commercial plant was designed and built by CWT, partially using grant funds, in Carthage, Missouri, to process animal residues from a nearby turkey processingmore » plant. The DOE sponsored program consisted of four tasks. These were: Task 1 Optimization of the CWT Plant in Carthage - This task focused on advancing and optimizing the process plant operated by CWT that converts organic waste to fuel and energy. Task 2 Characterize and Validate Fuels Produced by CWT - This task focused on testing of bio-derived hydrocarbon fuels from the Carthage plant in power generating equipment to determine the regulatory compliance of emissions and overall performance of the fuel. Task 3 Characterize Mixed Waste Streams - This task focused on studies performed at Princeton University to better characterize mixed waste incoming streams from animal and vegetable residues. Task 4 Fundamental Research in Waste Processing Technologies - This task focused on studies performed at the Massachusetts Institute of Technology (MIT) on the chemical reformation reaction of agricultural biomass compounds in a hydrothermal medium. Many of the challenges to optimize, improve and perfect the technology, equipment and processes in order to provide an economically viable means of creating sustainable energy were identified in the DOE Stage Gate Review, whose summary report was issued on July 30, 2004. This summary report appears herein as Appendix 1, and the findings of the report formed the basis for much of the subsequent work under the grant. An explanation of the process is presented as well as the completed work on the four tasks.« less

Multitasking: Effects of processing multiple auditory feature patterns

PubMed Central

Miller, Tova; Chen, Sufen; Lee, Wei Wei; Sussman, Elyse S.

2016-01-01

ERPs and behavioral responses were measured to assess how task-irrelevant sounds interact with task processing demands and affect the ability to monitor and track multiple sound events. Participants listened to four-tone sequential frequency patterns, and responded to frequency pattern deviants (reversals of the pattern). Irrelevant tone feature patterns (duration and intensity) and respective pattern deviants were presented together with frequency patterns and frequency pattern deviants in separate conditions. Responses to task-relevant and task-irrelevant feature pattern deviants were used to test processing demands for irrelevant sound input. Behavioral performance was significantly better when there were no distracting feature patterns. Errors primarily occurred in response to the to-be-ignored feature pattern deviants. Task-irrelevant elicitation of ERP components was consistent with the error analysis, indicating a level of processing for the irrelevant features. Task-relevant elicitation of ERP components was consistent with behavioral performance, demonstrating a “cost” of performance when there were two feature patterns presented simultaneously. These results provide evidence that the brain tracked the irrelevant duration and intensity feature patterns, affecting behavioral performance. Overall, our results demonstrate that irrelevant informational streams are processed at a cost, which may be considered a type of multitasking that is an ongoing, automatic processing of taskirrelevant sensory events. PMID:25939456

Task preparation processes related to reward prediction precede those related to task-difficulty expectation

PubMed Central

Schevernels, Hanne; Krebs, Ruth M.; Santens, Patrick; Woldorff, Marty G.; Boehler, C. Nico

2013-01-01

Recently, attempts have been made to disentangle the neural underpinnings of preparatory processes related to reward and attention. Functional magnetic resonance imaging (fMRI) research showed that neural activity related to the anticipation of reward and to attentional demands invokes neural activity patterns featuring large-scale overlap, along with some differences and interactions. Due to the limited temporal resolution of fMRI, however, the temporal dynamics of these processes remain unclear. Here, we report an event-related potentials (ERP) study in which cued attentional demands and reward prospect were combined in a factorial design. Results showed that reward prediction dominated early cue processing, as well as the early and later parts of the contingent negative variation (CNV) slow-wave ERP component that has been associated with task-preparation processes. Moreover these reward-related electrophysiological effects correlated across participants with response-time speeding on reward-prospect trials. In contrast, cued attentional demands affected only the later part of the CNV, with the highest amplitudes following cues predicting high-difficulty potential-reward targets, thus suggesting maximal task preparation when the task requires it and entails reward prospect. Consequently, we suggest that task-preparation processes triggered by reward can arise earlier, and potentially more directly, than strategic top-down aspects of preparation based on attentional demands. PMID:24064071

Accurate expectancies diminish perceptual distraction during visual search

PubMed Central

Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

2014-01-01

The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

Selective processing of threatening information: effects of attachment representation and anxiety disorder on attention and memory.

PubMed

Zeijlmans van Emmichoven, Ingeborg A; van IJzendoorn, Marinus H; de Ruiter, Corine; Brosschot, Jos F

2003-01-01

To investigate the effect of the mental representation of attachment on information processing, 28 anxiety disorder outpatients, as diagnosed by the Anxiety Disorders Interview Schedule-Revised, were administered the Adult Attachment Interview and the State-Trait Anxiety Inventory. They also completed an emotional Stroop task with subliminal and supraliminal exposure conditions, a free recall memory task, and a recognition test. All tasks contained threatening, neutral, and positively valenced stimuli. A nonclinical comparison group of 56 participants completed the same measures. Results on the Stroop task showed color-naming interference for threatening words in the supraliminal condition only. Nonclinical participants with insecure attachment representations showed a global response inhibition to the Stroop task. Clinical participants with secure attachment representations showed the largest Stroop interference of the threatening words compared to the other groups. Results on the free recall task showed superior recall of all types of stimuli by participants with secure attachment representations. In the outpatient group, participants with secure attachment representations showed superior recall of threatening words on the free recall task, compared to insecure participants. Results on the recognition task showed no differences between attachment groups. We conclude that secure attachment representations are characterized by open communication about and processing of threatening information, leading to less defensive exclusion of negative material during the attentional stage of information processing and to better recall of threatening information in a later stage. Attachment insecurity, but not the type of insecurity, seems a decisive factor in attention and memory processes.

Electrophysiologically dissociating episodic preretrieval processing.

PubMed

Bridger, Emma K; Mecklinger, Axel

2012-06-01

Contrasts between ERPs elicited by new items from tests with distinct episodic retrieval requirements index preretrieval processing. Preretrieval operations are thought to facilitate the recovery of task-relevant information because they have been shown to correlate with response accuracy in tasks in which prioritizing the retrieval of this information could be a useful strategy. This claim was tested here by contrasting new item ERPs from two retrieval tasks, each designed to explicitly require the recovery of a different kind of mnemonic information. New item ERPs differed from 400 msec poststimulus, but the distribution of these effects varied markedly, depending upon participants' response accuracy: A protracted posteriorly located effect was present for higher performing participants, whereas an anteriorly distributed effect occurred for lower performing participants. The magnitude of the posterior effect from 400 to 800 msec correlated with response accuracy, supporting the claim that preretrieval processes facilitate the recovery of task-relevant information. Additional contrasts between ERPs from these tasks and an old/new recognition task operating as a relative baseline revealed task-specific effects with nonoverlapping scalp topographies, in line with the assumption that these new item ERP effects reflect qualitatively distinct retrieval operations. Similarities in these effects were also used to reason about preretrieval processes related to the general requirement to recover contextual details. These insights, alongside the distinct pattern of effects for the two accuracy groups, reveal the multifarious nature of preretrieval processing while indicating that only some of these classes of operation are systematically related to response accuracy in recognition memory tasks.

A comparison of visuomotor cue integration strategies for object placement and prehension.

PubMed

Greenwald, Hal S; Knill, David C

2009-01-01

Visual cue integration strategies are known to depend on cue reliability and how rapidly the visual system processes incoming information. We investigated whether these strategies also depend on differences in the information demands for different natural tasks. Using two common goal-oriented tasks, prehension and object placement, we determined whether monocular and binocular information influence estimates of three-dimensional (3D) orientation differently depending on task demands. Both tasks rely on accurate 3D orientation estimates, but 3D position is potentially more important for grasping. Subjects placed an object on or picked up a disc in a virtual environment. On some trials, the monocular cues (aspect ratio and texture compression) and binocular cues (e.g., binocular disparity) suggested slightly different 3D orientations for the disc; these conflicts either were present upon initial stimulus presentation or were introduced after movement initiation, which allowed us to quantify how information from the cues accumulated over time. We analyzed the time-varying orientations of subjects' fingers in the grasping task and those of the object in the object placement task to quantify how different visual cues influenced motor control. In the first experiment, different subjects performed each task, and those performing the grasping task relied on binocular information more when orienting their hands than those performing the object placement task. When subjects in the second experiment performed both tasks in interleaved sessions, binocular cues were still more influential during grasping than object placement, and the different cue integration strategies observed for each task in isolation were maintained. In both experiments, the temporal analyses showed that subjects processed binocular information faster than monocular information, but task demands did not affect the time course of cue processing. How one uses visual cues for motor control depends on the task being performed, although how quickly the information is processed appears to be task invariant.