Sample records for performance previous work

  1. Alternative performance measures for evaluating congestion.

    DOT National Transportation Integrated Search

    2004-04-01

    This report summarizes the results of the work performed under the project Alternative Performance Measures for Evaluating : Congestion. The study first outlines existing approaches to looking at congestion. It then builds on the previous work in the...

  2. Impact of Previous Pharmacy Work Experience on Pharmacy School Academic Performance

    PubMed Central

    Mar, Ellena; T-L Tang, Terrill; Sasaki-Hill, Debra; Kuperberg, James R.; Knapp, Katherine

    2010-01-01

    Objectives To determine whether students' previous pharmacy-related work experience was associated with their pharmacy school performance (academic and clinical). Methods The following measures of student academic performance were examined: pharmacy grade point average (GPA), scores on cumulative high-stakes examinations, and advanced pharmacy practice experience (APPE) grades. The quantity and type of pharmacy-related work experience each student performed prior to matriculation was solicited through a student survey instrument. Survey responses were correlated with academic measures, and demographic-based stratified analyses were conducted. Results No significant difference in academic or clinical performance between those students with prior pharmacy experience and those without was identified. Subanalyses by work setting, position type, and substantial pharmacy work experience did not reveal any association with student performance. A relationship was found, however, between age and work experience, ie, older students tended to have more work experience than younger students. Conclusions Prior pharmacy work experience did not affect students' overall academic or clinical performance in pharmacy school. The lack of significant findings may have been due to the inherent practice limitations of nonpharmacist positions, changes in pharmacy education, and the limitations of survey responses. PMID:20498735

  3. Gender Differences and Styles in the Use of Digital Games

    ERIC Educational Resources Information Center

    Bonanno, Philip; Kommers, P. A. M.

    2005-01-01

    This paper reports work in progress investigating gender differences and styles in the use of digital games amongst advanced level biology students. It is an elaboration on previous work exploring the relationship between cognitive style and academic performance in Maltese students taking biology at advanced level. In this previous work the…

  4. 48 CFR 514.270-7 - Guidelines for using the price list method.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... work anticipated to be performed during normal working hours. (3) List the unit prices for work to be performed during both normal working hours and outside of normal working hours. (4) Define “normal” in terms of hours and days of the week. (5) Advise bidders of the previous year's total expenditures or...

  5. Impact of mental disorders on work performance in a community sample of workers in Japan: the World Mental Health Japan Survey 2002-2005.

    PubMed

    Tsuchiya, Masao; Kawakami, Norito; Ono, Yutaka; Nakane, Yoshibumi; Nakamura, Yosikazu; Fukao, Akira; Tachimori, Hisateru; Iwata, Noboru; Uda, Hidenori; Nakane, Hideyuki; Watanabe, Makoto; Oorui, Masashi; Naganuma, Yoichi; Furukawa, Toshiaki A; Kobayashi, Masayo; Ahiko, Tadayuki; Takeshima, Tadashi; Kikkawa, Takehiko

    2012-06-30

    Most studies that investigate the impact of mental disorders on work performance have been conducted in Western countries, but this study examines the impact of common mental disorders on sick leave and on-the-job work performance in a community sample of Japanese workers. Data from the World Mental Health Japan survey were analyzed. A subsample of 530 workers aged 20-60years were interviewed using the WHO Composite International Diagnostic Interview 3.0. The WHO Health and Work Performance Questionnaire, was used to assess sick days and on-the-job work performance for the previous 30days. Linear regression was used to estimate the impact of mental disorders on these indicators of work performance over 12months. Mood disorders, including major depressive disorder, and alcohol abuse/dependence were significantly associated with decreased on-the-job performance. There were no significant associations between mental disorders and sick/absent days. Consistent with previous studies, major depression has a great impact on on-the-job work performance in Japan. The lost productivity was estimated at approximately 28-30 lost days per year. A similar decrease in on-the-job work performance was found for alcohol abuse/dependence, which is stronger than that in other countries, probably attributable to greater tolerance of problematic drinking at Japanese worksites. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.; Grady, Jean (Technical Monitor)

    2005-01-01

    This Final Report summarizes work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-368. The Agreement is entitled "Constellation X-ray Mission Study and Support." The report covers the full duration of the Agreement which ran from October 1,1998 to October 14,2004. Included in the report is a description of previously unreported work that was performed between October 2003 and the end of the Agreement. For convenience, the previously unreported work is covered first in Section 2.0. Then, an overall summary of all work performed under the Agreement is presented in Section 3. Section 4.0 contains a list of all formal reports that SAO has submitted to GSFC along with publications and presentations at various conferences.

  7. Do Work Placements Improve Final Year Academic Performance or Do High-Calibre Students Choose to Do Work Placements?

    ERIC Educational Resources Information Center

    Jones, C. M.; Green, J. P.; Higson, H. E.

    2017-01-01

    This study investigates whether the completion of an optional sandwich work placement enhances student performance in final year examinations. Using Propensity Score Matching, our analysis departs from the literature by controlling for self-selection. Previous studies may have overestimated the impact of sandwich work placements on performance…

  8. Both a Nicotinic Single Nucleotide Polymorphism (SNP) and a Noradrenergic SNP Modulate Working Memory Performance when Attention Is Manipulated

    ERIC Educational Resources Information Center

    Greenwood, Pamela M.; Sundararajan, Ramya; Lin, Ming-Kuan; Kumar, Reshma; Fryxell, Karl J.; Parasuraman, Raja

    2009-01-01

    We investigated the relation between the two systems of visuospatial attention and working memory by examining the effect of normal variation in cholinergic and noradrenergic genes on working memory performance under attentional manipulation. We previously reported that working memory for location was impaired following large location precues,…

  9. Receiving treatment, labor force activity, and work performance among people with psychiatric disorders: results from a population survey.

    PubMed

    Waghorn, Geoffrey; Chant, David

    2011-12-01

    Standard treatments for psychiatric disorders such as schizophrenia, depression and anxiety disorders are generally expected to benefit individuals, employers, and the wider community through improvements in work-functioning and productivity. We repeated a previous secondary investigation of receiving treatment, labor force activity and self-reported work performance among people with ICD-10 psychiatric disorders, in comparison to people with other types of health conditions. Data were collected by the Australian Bureau of Statistics in 2003 repeating a survey administered in 1998 using representative multistage sampling strategies. The 2003 household probability sample consisted of 36,241 working age individuals. Consistent with the previous secondary investigation based on the 1998 survey administration, receiving treatment was consistently associated with non-participation in the labor force, and was negatively associated with work performance. At a population level, receiving treatment was negatively associated with labor force activity and work performance. The stability of these results in two independent surveys highlights the need to investigate the longitudinal relationships between evidence-based treatments for psychiatric conditions as applied in real-world settings, and labor force participation and work performance outcomes.

  10. The Impact of Automation Reliability and Operator Fatigue on Performance and Reliance

    DTIC Science & Technology

    2016-09-23

    Matthews1 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER H0HJ (53290813) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8... performance . Reliability Reliability of automation is a key factor in an operator’s reliance on automation. Previous work has shown that... Performance in a complex multiple-task environment during a laboratory-based simulation of occasional night work . Human Factors: The Journal of the

  11. Working Memory and Literacy as Predictors of Performance on Algebraic Word Problems

    ERIC Educational Resources Information Center

    Lee, Kerry; Ng, Swee-Fong; Ng, Ee-Lynn; Lim, Zee-Ying

    2004-01-01

    Previous studies on individual differences in mathematical abilities have shown that working memory contributes to early arithmetic performance. In this study, we extended the investigation to algebraic word problem solving. A total of 151 10-year-olds were administered algebraic word problems and measures of working memory, intelligence quotient…

  12. REPEATED INHALATION OF TOLUENE BY RATS PERFORMING A SIGNAL DETECTION TASK LEADS TO BEHVIORAL TOLERANCE ON SOME PERFORMANCE MEASURES.

    EPA Science Inventory

    Previous work showed that trichloroethylene (TCE) impairs sustained attention as evidenced by a reduction in accuracy and elevation of response latencies in rats trained to perform a visual signal detection task (SDT). This work also showed that these effects abate during repeat...

  13. Neuropsychological sequelae of work-stress-related exhaustion.

    PubMed

    Österberg, Kai; Skogsliden, Sofia; Karlson, Björn

    2014-01-01

    The aim was to assess long-term cognitive performance after substantial recovery from work-stress-related exhaustion, in relation to subjective cognitive complaints and return to active work. In total, 54 patients previously diagnosed with work-stress-related exhaustion participated in a neuropsychological examination ∼2 years after initial sick leave. Most participants were substantially recovered at follow-up, with only 13% still meeting the criteria for exhaustion disorder suggested by the Swedish National Board of Health and Welfare. When participants' scores on 14 neuropsychological tests were compared to a matched group of 50 controls, the former patient group showed lower performance mainly on attention tests of the reaction time type, but also slightly lower scores on visuo-spatial constructional ability. However, the former patient group performed better than controls on two memory tests and, in part, on a test of simultaneous capacity. Self-ratings of everyday cognitive problems remained significantly higher in the former patient group than among controls, but the extent of self-rated cognitive problems was generally unrelated to performance on the neuropsychological tests. No relationship between performance on these tests and the extent of work resumption was observed. In summary, persons with previous work-stress-related exhaustion showed persistent signs of a minor attention deficit, despite considerable general recovery and return to work.

  14. The Effect of Job Resources on Work Engagement: A Study on Academicians in Turkey

    ERIC Educational Resources Information Center

    Altunel, Mustafa C.; Kocak, Omer Erdem; Cankir, Bilal

    2015-01-01

    Conducting research and publishing these research papers in academic journals is an accepted norm in the academic world. Previous studies prove that work engagement is a significant predictor of performance. Herein, the relationship between work engagement, which is assumed as a substitute for performance, and job resources is examined. At least…

  15. Prefrontal Hemodynamics of Physical Activity and Environmental Complexity During Cognitive Work.

    PubMed

    McKendrick, Ryan; Mehta, Ranjana; Ayaz, Hasan; Scheldrup, Melissa; Parasuraman, Raja

    2017-02-01

    The aim of this study was to assess performance and cognitive states during cognitive work in the presence of physical work and in natural settings. Authors of previous studies have examined the interaction between cognitive and physical work, finding performance decrements in working memory. Neuroimaging has revealed increases and decreases in prefrontal oxygenated hemoglobin during the interaction of cognitive and physical work. The effect of environment on cognitive-physical dual tasking has not been previously considered. Thirteen participants were monitored with wireless functional near-infrared spectroscopy (fNIRS) as they performed an auditory 1-back task while sitting, walking indoors, and walking outdoors. Relative to sitting and walking indoors, auditory working memory performance declined when participants were walking outdoors. Sitting during the auditory 1-back task increased oxygenated hemoglobin and decreased deoxygenated hemoglobin in bilateral prefrontal cortex. Walking reduced the total hemoglobin available to bilateral prefrontal cortex. An increase in environmental complexity reduced oxygenated hemoglobin and increased deoxygenated hemoglobin in bilateral prefrontal cortex. Wireless fNIRS is capable of monitoring cognitive states in naturalistic environments. Selective attention and physical work compete with executive processing. During executive processing loading of selective attention and physical work results in deactivation of bilateral prefrontal cortex and degraded working memory performance, indicating that physical work and concomitant selective attention may supersede executive processing in the distribution of mental resources. This research informs decision-making procedures in work where working memory, physical activity, and attention interact. Where working memory is paramount, precautions should be taken to eliminate competition from physical work and selective attention.

  16. Do perceived high performance work systems influence the relationship between emotional labour, burnout and intention to leave? A study of Australian nurses.

    PubMed

    Bartram, Timothy; Casimir, Gian; Djurkovic, Nick; Leggat, Sandra G; Stanton, Pauline

    2012-07-01

    The purpose of this article was to explore the relationships between perceived high performance work systems, emotional labour, burnout and intention to leave among nurses in Australia. Previous studies show that emotional labour and burnout are associated with an increase in intention to leave of nurses. There is evidence that high performance work systems are in association with a decrease in turnover. There are no previous studies that examine the relationship between high performance work systems and emotional labour. A cross-sectional, correlational survey. The study was conducted in Australia in 2008 with 183 nurses. Three hypotheses were tested with validated measures of emotional labour, burnout, intention to leave, and perceived high performance work systems. Principal component analysis was used to examine the structure of the measures. The mediation hypothesis was tested using Baron and Kenny's procedure and the moderation hypothesis was tested using hierarchical regression and the product-term. Emotional labour is positively associated with both burnout and intention to leave. Burnout mediates the relationship between emotional labour and intention to leave. Perceived high performance work systems negatively moderates the relationship between emotional labour and burnout. Perceived high performance work systems not only reduces the strength of the negative effect of emotional labour on burnout but also has a unique negative effect on intention to leave. Ensuring effective human resource management practice through the implementation of high performance work systems may reduce the burnout associated with emotional labour. This may assist healthcare organizations to reduce nurse turnover. © 2012 Blackwell Publishing Ltd.

  17. Code Modernization of VPIC

    NASA Astrophysics Data System (ADS)

    Bird, Robert; Nystrom, David; Albright, Brian

    2017-10-01

    The ability of scientific simulations to effectively deliver performant computation is increasingly being challenged by successive generations of high-performance computing architectures. Code development to support efficient computation on these modern architectures is both expensive, and highly complex; if it is approached without due care, it may also not be directly transferable between subsequent hardware generations. Previous works have discussed techniques to support the process of adapting a legacy code for modern hardware generations, but despite the breakthroughs in the areas of mini-app development, portable-performance, and cache oblivious algorithms the problem still remains largely unsolved. In this work we demonstrate how a focus on platform agnostic modern code-development can be applied to Particle-in-Cell (PIC) simulations to facilitate effective scientific delivery. This work builds directly on our previous work optimizing VPIC, in which we replaced intrinsic based vectorisation with compile generated auto-vectorization to improve the performance and portability of VPIC. In this work we present the use of a specialized SIMD queue for processing some particle operations, and also preview a GPU capable OpenMP variant of VPIC. Finally we include a lessons learnt. Work performed under the auspices of the U.S. Dept. of Energy by the Los Alamos National Security, LLC Los Alamos National Laboratory under contract DE-AC52-06NA25396 and supported by the LANL LDRD program.

  18. Transformer Incipient Fault Prediction Using Combined Artificial Neural Network and Various Particle Swarm Optimisation Techniques.

    PubMed

    Illias, Hazlee Azil; Chai, Xin Rui; Abu Bakar, Ab Halim; Mokhlis, Hazlie

    2015-01-01

    It is important to predict the incipient fault in transformer oil accurately so that the maintenance of transformer oil can be performed correctly, reducing the cost of maintenance and minimise the error. Dissolved gas analysis (DGA) has been widely used to predict the incipient fault in power transformers. However, sometimes the existing DGA methods yield inaccurate prediction of the incipient fault in transformer oil because each method is only suitable for certain conditions. Many previous works have reported on the use of intelligence methods to predict the transformer faults. However, it is believed that the accuracy of the previously proposed methods can still be improved. Since artificial neural network (ANN) and particle swarm optimisation (PSO) techniques have never been used in the previously reported work, this work proposes a combination of ANN and various PSO techniques to predict the transformer incipient fault. The advantages of PSO are simplicity and easy implementation. The effectiveness of various PSO techniques in combination with ANN is validated by comparison with the results from the actual fault diagnosis, an existing diagnosis method and ANN alone. Comparison of the results from the proposed methods with the previously reported work was also performed to show the improvement of the proposed methods. It was found that the proposed ANN-Evolutionary PSO method yields the highest percentage of correct identification for transformer fault type than the existing diagnosis method and previously reported works.

  19. Transformer Incipient Fault Prediction Using Combined Artificial Neural Network and Various Particle Swarm Optimisation Techniques

    PubMed Central

    2015-01-01

    It is important to predict the incipient fault in transformer oil accurately so that the maintenance of transformer oil can be performed correctly, reducing the cost of maintenance and minimise the error. Dissolved gas analysis (DGA) has been widely used to predict the incipient fault in power transformers. However, sometimes the existing DGA methods yield inaccurate prediction of the incipient fault in transformer oil because each method is only suitable for certain conditions. Many previous works have reported on the use of intelligence methods to predict the transformer faults. However, it is believed that the accuracy of the previously proposed methods can still be improved. Since artificial neural network (ANN) and particle swarm optimisation (PSO) techniques have never been used in the previously reported work, this work proposes a combination of ANN and various PSO techniques to predict the transformer incipient fault. The advantages of PSO are simplicity and easy implementation. The effectiveness of various PSO techniques in combination with ANN is validated by comparison with the results from the actual fault diagnosis, an existing diagnosis method and ANN alone. Comparison of the results from the proposed methods with the previously reported work was also performed to show the improvement of the proposed methods. It was found that the proposed ANN-Evolutionary PSO method yields the highest percentage of correct identification for transformer fault type than the existing diagnosis method and previously reported works. PMID:26103634

  20. Overworked? An Observation of the Relationship between Student Employment and Academic Performance

    ERIC Educational Resources Information Center

    Logan, Jennifer; Hughes, Traci; Logan, Brian

    2016-01-01

    Current observations from the National Center for Education Statistics demonstrate the dramatic increase in college student employment over the past few decades. Not only are more students employed than in previous decades, students are working more hours. This could lead to declines in academic performance as hours worked increase, resulting in…

  1. Balancing the costs of mobility investments in work zones : phase 1 final report.

    DOT National Transportation Integrated Search

    2015-06-01

    Work zone safety and mobility continue to be critical transportation concerns in Michigan and elsewhere. : Previous research has led to the development of a variety of tools, performance measures and decision-making frameworks to analyze work zone sa...

  2. PCM-SABRE: a platform for benchmarking and comparing outcome prediction methods in precision cancer medicine.

    PubMed

    Eyal-Altman, Noah; Last, Mark; Rubin, Eitan

    2017-01-17

    Numerous publications attempt to predict cancer survival outcome from gene expression data using machine-learning methods. A direct comparison of these works is challenging for the following reasons: (1) inconsistent measures used to evaluate the performance of different models, and (2) incomplete specification of critical stages in the process of knowledge discovery. There is a need for a platform that would allow researchers to replicate previous works and to test the impact of changes in the knowledge discovery process on the accuracy of the induced models. We developed the PCM-SABRE platform, which supports the entire knowledge discovery process for cancer outcome analysis. PCM-SABRE was developed using KNIME. By using PCM-SABRE to reproduce the results of previously published works on breast cancer survival, we define a baseline for evaluating future attempts to predict cancer outcome with machine learning. We used PCM-SABRE to replicate previous work that describe predictive models of breast cancer recurrence, and tested the performance of all possible combinations of feature selection methods and data mining algorithms that was used in either of the works. We reconstructed the work of Chou et al. observing similar trends - superior performance of Probabilistic Neural Network (PNN) and logistic regression (LR) algorithms and inconclusive impact of feature pre-selection with the decision tree algorithm on subsequent analysis. PCM-SABRE is a software tool that provides an intuitive environment for rapid development of predictive models in cancer precision medicine.

  3. Crafting in context: Exploring when job crafting is dysfunctional for performance effectiveness.

    PubMed

    Dierdorff, Erich C; Jensen, Jaclyn M

    2018-05-01

    Job crafting theory purports that the consequences of revising one's work role can be simultaneously beneficial and detrimental. Previous research, however, has almost exclusively emphasized the beneficial outcomes of job crafting. In the current study, we proposed dysfunctional consequences of crafting for performance-related outcomes in the form of a U-shaped relationship between job crafting and performance effectiveness (managerial ratings of job proficiency and peer ratings of citizenship behavior). We further predicted that elements of the task context (autonomy and ambiguity) and the social context (interdependence and social support) moderate these curvilinear relationships. Consistent with previous research, job crafting displayed positive and linear effects on work-related attitudes (job satisfaction and affective commitment). Consistent with our predictions, moderate levels of crafting were associated with dysfunctional performance-related outcomes and features of work context either exacerbated or dissipated these dysfunctional consequences of job crafting for individuals. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  4. High energy PIXE: A tool to characterize multi-layer thick samples

    NASA Astrophysics Data System (ADS)

    Subercaze, A.; Koumeir, C.; Métivier, V.; Servagent, N.; Guertin, A.; Haddad, F.

    2018-02-01

    High energy PIXE is a useful and non-destructive tool to characterize multi-layer thick samples such as cultural heritage objects. In a previous work, we demonstrated the possibility to perform quantitative analysis of simple multi-layer samples using high energy PIXE, without any assumption on their composition. In this work an in-depth study of the parameters involved in the method previously published is proposed. Its extension to more complex samples with a repeated layer is also presented. Experiments have been performed at the ARRONAX cyclotron using 68 MeV protons. The thicknesses and sequences of a multi-layer sample including two different layers of the same element have been determined. Performances and limits of this method are presented and discussed.

  5. Persistent Neuronal Firing in Primary Somatosensory Cortex in the Absence of Working Memory of Trial-Specific Features of the Sample Stimuli in a Haptic Working Memory Task

    ERIC Educational Resources Information Center

    Wang, Liping; Li, Xianchun; Hsiao, Steven S.; Bodner, Mark; Lenz, Fred; Zhou, Yong-Di

    2012-01-01

    Previous studies suggested that primary somatosensory (SI) neurons in well-trained monkeys participated in the haptic-haptic unimodal delayed matching-to-sample (DMS) task. In this study, 585 SI neurons were recorded in monkeys performing a task that was identical to that in the previous studies but without requiring discrimination and active…

  6. The Relationship between Work-Life Conflict/Work-Life Balance and Operational Effectiveness in the Canadian Forces

    DTIC Science & Technology

    2006-12-01

    life conflict/ work - life balance and performance has primarily used non-military populations . Accordingly, the findings that are discussed in this... using CF personnel but also more generally to the research on work - life conflict/ work - life balance . As discussed previously, most of the recent research...conflict/ work - life balance and operational effectiveness in CF members. Work -family conflict,

  7. Suppressing Irrelevant Information from Working Memory: Evidence for Domain-Specific Deficits in Poor Comprehenders

    ERIC Educational Resources Information Center

    Pimperton, Hannah; Nation, Kate

    2010-01-01

    Previous research has suggested that children with specific reading comprehension deficits (poor comprehenders) show an impaired ability to suppress irrelevant information from working memory, with this deficit detrimentally impacting on their working memory ability, and consequently limiting their reading comprehension performance. However, the…

  8. Improving Children's Working Memory and Classroom Performance

    ERIC Educational Resources Information Center

    St Clair-Thompson, Helen; Stevens, Ruth; Hunt, Alexandra; Bolder, Emma

    2010-01-01

    Previous research has demonstrated close relationships between working memory and children's scholastic attainment. The aim of the present study was to explore a method of improving working memory, using memory strategy training. Two hundred and fifty-four children aged five to eight years were tested on measures of the phonological loop,…

  9. The Influence of Pre-stimulus EEG Activity on Reaction Time During a Verbal Sternberg Task is Related to Musical Expertise.

    PubMed

    Klein, Carina; Diaz Hernandez, Laura; Koenig, Thomas; Kottlow, Mara; Elmer, Stefan; Jäncke, Lutz

    2016-01-01

    Previous work highlighted the possibility that musical training has an influence on cognitive functioning. The suggested reason for this influence is the strong recruitment of attention, planning, and working memory functions during playing a musical instrument. The purpose of the present work was twofold, namely to evaluate the general relationship between pre-stimulus electrophysiological activity and cognition, and more specifically the influence of musical expertise on working memory functions. With this purpose in mind, we used covariance mapping analyses to evaluate whether pre-stimulus electroencephalographic activity is predictive for reaction time during a visual working memory task (Sternberg paradigm) in musicians and non-musicians. In line with our hypothesis, we replicated previous findings pointing to a general predictive value of pre-stimulus activity for working memory performance. Most importantly, we also provide first evidence for an influence of musical expertise on working memory performance that could distinctively be predicted by pre-stimulus spectral power. Our results open novel perspectives for better comprehending the vast influences of musical expertise on cognition.

  10. Work assignments, delegation of tasks and job satisfaction among Danish dental hygienists.

    PubMed

    Hach, M; Aaberg, K B; Lempert, S M; Danielsen, B

    2017-08-01

    Recent legislation in Denmark has made it possible for dentists to delegate their tasks to dental hygienists. Previous studies have shown that Danish dental hygienists primarily were performing assignments within their own work field. These assignments include prophylaxis or instructing patients in oral health care. However, studies have also shown that Danish dental hygienists performed dental nurse assignments such as chair-side assistance, unit cleaning and disinfection of instruments. The objectives of this study were to investigate (i) the range of work assignments performed by Danish dental hygienists, (ii) the types of dentist tasks performed by Danish dental hygienists and (iii) job satisfaction among Danish dental hygienists. Dental hygienists graduating in 2004-2007 were invited to participate in this study. Participants answered an email-distributed questionnaire. The questionnaire consisted of questions regarding job satisfaction, assignments performed, postgraduate course attendance, receiving assistance from a dental nurse and which work assignments Danish dental hygienists wish to perform in the future. The results of this study showed that 90% of Danish dental hygienists were satisfied with their job and 52% were performing dentists' tasks. Among dentists' tasks performed by Danish dental hygienists, invasive caries therapy was the most frequently performed task. The type of assignments performed by Danish dental hygienists today appears to be changing compared to previous studies. From initially performing prophylaxis and chair-side assistance for the dentist, Danish dental hygienists today are performing a wider range of tasks which includes dentists' tasks. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Grizzly Staus Report

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

    Spencer, Benjamin; Zhang, Yongfeng; Chakraborty, Pritam

    2014-09-01

    This report summarizes work during FY 2014 to develop capabilities to predict embrittlement of reactor pressure vessel steel, and to assess the response of embrittled reactor pressure vessels to postulated accident conditions. This work has been conducted a three length scales. At the engineering scale, 3D fracture mechanics capabilities have been developed to calculate stress intensities and fracture toughnesses, to perform a deterministic assessment of whether a crack would propagate at the location of an existing flaw. This capability has been demonstrated on several types of flaws in a generic reactor pressure vessel model. Models have been developed at themore » scale of fracture specimens to develop a capability to determine how irradiation affects the fracture toughness of material. Verification work has been performed on a previously-developed model to determine the sensitivity of the model to specimen geometry and size effects. The effects of irradiation on the parameters of this model has been investigated. At lower length scales, work has continued in an ongoing to understand how irradiation and thermal aging affect the microstructure and mechanical properties of reactor pressure vessel steel. Previously-developed atomistic kinetic monte carlo models have been further developed and benchmarked against experimental data. Initial work has been performed to develop models of nucleation in a phase field model. Additional modeling work has also been performed to improve the fundamental understanding of the formation mechanisms and stability of matrix defects caused.« less

  12. LTPP : 2002 year in review

    DOT National Transportation Integrated Search

    2003-04-01

    In 2002, as in previous years, the Long Term Pavement Performance (LTPP) program continued working to provide a better understanding of the "hows" and "whys" of pavement performance. This report outlines LTPP's 2002 program area accomplishments and p...

  13. Shock-Bubble Heating of the Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Friedman, Samuel H.; Heinz, S.; Churazov, E.

    2011-01-01

    Active galactic nuclei (AGN) Feedback via extragalactic jets requires a thermalization of the energy injected into the intracluster medium (ICM) in order for energy feedback to occur. Heinz and Churazov (2005) proposed a method using shock waves and previously inflated bubbles in the ICM to extract energy from the shock waves and turn the energy into rotational kinetic energy. This energy would decay and allow heating to occur elsewhere throughout the galaxy cluster. In this paper, we extend to three dimensions (3D) the previous work using hydrodynamic simulations. We also compare our results to previous related work done performed experimentally.

  14. Who wants to work with older people? Swedish student nurses' willingness to work in elderly care--a questionnaire study.

    PubMed

    Carlson, Elisabeth; Idvall, Ewa

    2015-07-01

    The aging population is a globally recognized challenge for the health care service. The growing number of older people will probably lead to increased demands for nurses working in elderly care. Clinical practice has been shown to have an impact on how student nurses perceive a particular field of nursing. To compare perceptions of the clinical learning environment in nursing homes among students considering a career in aged care or not, and to examine the difference in age, gender and previous working experience as health care assistants in elderly care between the two groups. This was a cross-sectional study using the Swedish version of the Clinical Learning Environment and Nurse Teacher evaluation scale. Consecutive sampling was performed over three semesters from September 2011 to December 2012. The survey was conducted with 183 student nurses. Mann-Whitney U-test was used to examine differences in relation to two groups namely student nurses who did or did not consider to work in elderly care. A chi-square test of independence was performed to examine the difference in age, gender and previous working experience between the two groups. The analysis leaned towards an overall positive evaluation of the clinical learning environment with more positive values for students considering a career. There were no significant differences between younger students (18-23) and older students (24-50) regarding willingness to work in elderly care or not. Neither was any significant difference displayed between students, based on gender nor for previous work experience. Age, gender and previous work experiences as health care assistants did not impact on students' willingness to work in elderly care. Future studies need to acknowledge the complexity of why student nurses choose a particular pathway in nursing by longitudinal studies following cohorts of students during the course of the nursing programme. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Verbal Working Memory Performance Correlates with Regional White Matter Structures in the Frontoparietal Regions

    ERIC Educational Resources Information Center

    Takeuchi, Hikaru; Taki, Yasuyuki; Sassa, Yuko; Hashizume, Hiroshi; Sekiguchi, Atsushi; Fukushima, Ai; Kawashima, Ryuta

    2011-01-01

    Working memory is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. Previous imaging studies have suggested that the frontoparietal regions are activated during working memory tasks; a putative association between the structure of the frontoparietal regions and working…

  16. Criteria of Police Officer Performance.

    ERIC Educational Resources Information Center

    Baehr, Melany E.

    The indifferent success in achieving the goal of reliable and valid police officer work performance measures has been attributed to the complexity of the job. This study explored reasons for unsatisfactory police performance evaluation, reviewing and integrating previous studies and new recently collected but not yet published data. Performance…

  17. Evaluating Faculty Work: Expectations and Standards of Faculty Performance in Research Universities

    ERIC Educational Resources Information Center

    Hardre, Patricia; Cox, Michelle

    2009-01-01

    Expectations and the way they are communicated can influence employees' motivation and performance. Previous research has demonstrated individual effects of workplace climate and individual differences on faculty productivity. The present study focused on the characteristics of institutional performance standards, evaluation processes and…

  18. Conscientiousness, openness to experience and extraversion as predictors of nursing work performance: a facet-level analysis.

    PubMed

    Ellershaw, Julia; Fullarton, Christie; Rodwell, John; Mcwilliams, John

    2016-03-01

    This study examined the relationships between the personality traits of conscientiousness, openness and extraversion at trait and facet-levels and three indicators of work role performance; proficiency, 'adaptivity' and proactivity measured at individual, team and organisational levels. This is one of the first studies to explore the relationship between personality, measured at trait and facet-level and performance using a comprehensive range of performance indicators. An online survey of 393 nurses from health-care organisations across Australia was conducted to test hypothesised relationships. Path analyses revealed numerous relationships between personality, measured at both trait and facet-levels, and work role performance. Conscientiousness was highlighted as the strongest driver of work role performance across all the indicators, with extraversion also strongly associated with work role performance. Openness to experience, previously considered a week predictor of performance, was, when examined at the facet-level, related to all of the work role performance indicators. Results suggests a bandwidth effect, where the personality traits drive global performance while the facets drive specific performance. Better understanding of the relationship between personality and work role performance will help nurse managers to foster the fit between individual and organisation, improving job satisfaction, engagement, retention and performance in role. © 2015 John Wiley & Sons Ltd.

  19. Gradient retention prediction of acid-base analytes in reversed phase liquid chromatography: a simplified approach for acetonitrile-water mobile phases.

    PubMed

    Andrés, Axel; Rosés, Martí; Bosch, Elisabeth

    2014-11-28

    In previous work, a two-parameter model to predict chromatographic retention of ionizable analytes in gradient mode was proposed. However, the procedure required some previous experimental work to get a suitable description of the pKa change with the mobile phase composition. In the present study this previous experimental work has been simplified. The analyte pKa values have been calculated through equations whose coefficients vary depending on their functional group. Forced by this new approach, other simplifications regarding the retention of the totally neutral and totally ionized species also had to be performed. After the simplifications were applied, new prediction values were obtained and compared with the previously acquired experimental data. The simplified model gave pretty good predictions while saving a significant amount of time and resources. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Carla J. Miller

    This report provides a summary of the literature review that was performed and based on previous work performed at the Idaho National Laboratory studying the Three Mile Island 2 (TMI-2) nuclear reactor accident, specifically the melted fuel debris. The purpose of the literature review was to document prior published work that supports the feasibility of the analytical techniques that were developed to provide quantitative results of the make-up of the fuel and reactor component debris located inside and outside the containment. The quantitative analysis provides a technique to perform nuclear fuel accountancy measurements

  1. Measuring Student Performance in General Organic Chemistry

    ERIC Educational Resources Information Center

    Austin, Ara C.; Ben-Daat, Hagit; Zhu, Mary; Atkinson, Robert; Barrows, Nathan; Gould, Ian R.

    2015-01-01

    Student performance in general organic chemistry courses is determined by a wide range of factors including cognitive ability, motivation and cultural capital. Previous work on cognitive factors has tended to focus on specific areas rather than exploring performance across all problem types and cognitive skills. In this study, we have categorized…

  2. Model-Based IN SITU Parameter Estimation of Ultrasonic Guided Waves in AN Isotropic Plate

    NASA Astrophysics Data System (ADS)

    Hall, James S.; Michaels, Jennifer E.

    2010-02-01

    Most ultrasonic systems employing guided waves for flaw detection require information such as dispersion curves, transducer locations, and expected propagation loss. Degraded system performance may result if assumed parameter values do not accurately reflect the actual environment. By characterizing the propagating environment in situ at the time of test, potentially erroneous a priori estimates are avoided and performance of ultrasonic guided wave systems can be improved. A four-part model-based algorithm is described in the context of previous work that estimates model parameters whereby an assumed propagation model is used to describe the received signals. This approach builds upon previous work by demonstrating the ability to estimate parameters for the case of single mode propagation. Performance is demonstrated on signals obtained from theoretical dispersion curves, finite element modeling, and experimental data.

  3. Personal vulnerability and work-home interaction: the effect of job performance-based self-esteem on work/home conflict and facilitation.

    PubMed

    Innstrand, Siw Tone; Langballe, Ellen Melbye; Espnes, Geir Arild; Aasland, Olaf Gjerløw; Falkum, Erik

    2010-12-01

    The aim of the present study was to examine the longitudinal relationship between job performance-based self-esteem (JPB-SE) and work-home interaction (WHI) in terms of the direction of the interaction (work-to-home vs. home-to-work) and the effect (conflict vs. facilitation). A sample of 3,475 respondents from eight different occupational groups (lawyers, physicians, nurses, teachers, church ministers, bus drivers, and people working in advertising and information technology) supplied data at two points of time with a two-year time interval. The two-wave, cross-lagged structural equations modeling (SEM) analysis demonstrated reciprocal relationships between these variables, i.e., job performance-based self-esteem may act as a precursor as well as an outcome of work-home interaction. The strongest association was between job performance-based self-esteem and work-to-home conflict. Previous research on work-home interaction has mainly focused on situational factors. This longitudinal study expands the work-home literature by demonstrating how individual vulnerability (job performance-based self-esteem) contributes to the explanation of work-home interactions. © 2010 The Authors. Scandinavian Journal of Psychology © 2010 The Scandinavian Psychological Associations.

  4. Seven-Year-Olds Allocate Attention Like Adults Unless Working Memory Is Overloaded

    ERIC Educational Resources Information Center

    Cowan, Nelson; Morey, Candice C.; AuBuchon, Angela M.; Zwilling, Christopher E.; Gilchrist, Amanda L.

    2010-01-01

    Previous studies have indicated that visual working memory performance increases with age in childhood, but it is not clear why. One main hypothesis has been that younger children are less efficient in their attention; specifically, they are less able to exclude irrelevant items from working memory to make room for relevant items. We examined this…

  5. Memory functions in chronic pain: examining contributions of attention and age to test performance.

    PubMed

    Oosterman, Joukje M; Derksen, Laura C; van Wijck, Albert J M; Veldhuijzen, Dieuwke S; Kessels, Roy P C

    2011-01-01

    Previous studies have revealed that memory performance is diminished in chronic pain patients. Few studies, however, have assessed multiple components of memory in a single sample. It is currently also unknown whether attentional problems, which are commonly observed in chronic pain, mediate the decline in memory. Finally, previous studies have focused on middle-aged adults, and a possible detrimental effect of aging on memory performance in chronic pain patients has been commonly disregarded. This study, therefore, aimed at describing the pattern of semantic, working, and visual and verbal episodic memory performance in participants with chronic pain, while testing for possible contributions of attention and age to task performance. Thirty-four participants with chronic pain and 32 pain-free participants completed tests of episodic, semantic, and working memory to assess memory performance and a test of attention. Participants with chronic pain performed worse on tests of working memory and verbal episodic memory. A decline in attention explained some, but not all, group differences in memory performance. Finally, no additional effect of age on the diminished task performance in participants with chronic pain was observed. Taken together, the results indicate that chronic pain significantly affects memory performance. Part of this effect may be caused by underlying attentional dysfunction, although this could not fully explain the observed memory decline. An increase in age in combination with the presence of chronic pain did not additionally affect memory performance.

  6. Confident failures: Lapses of working memory reveal a metacognitive blind spot.

    PubMed

    Adam, Kirsten C S; Vogel, Edward K

    2017-07-01

    Working memory performance fluctuates dramatically from trial to trial. On many trials, performance is no better than chance. Here, we assessed participants' awareness of working memory failures. We used a whole-report visual working memory task to quantify both trial-by-trial performance and trial-by-trial subjective ratings of inattention to the task. In Experiment 1 (N = 41), participants were probed for task-unrelated thoughts immediately following 20% of trials. In Experiment 2 (N = 30), participants gave a rating of their attentional state following 25% of trials. Finally, in Experiments 3a (N = 44) and 3b (N = 34), participants reported confidence of every response using a simple mouse-click judgment. Attention-state ratings and off-task thoughts predicted the number of items correctly identified on each trial, replicating previous findings that subjective measures of attention state predict working memory performance. However, participants correctly identified failures on only around 28% of failure trials. Across experiments, participants' metacognitive judgments reliably predicted variation in working memory performance but consistently and severely underestimated the extent of failures. Further, individual differences in metacognitive accuracy correlated with overall working memory performance, suggesting that metacognitive monitoring may be key to working memory success.

  7. 46 CFR 11.807 - Experience requirements for registry.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... assistant. Successful completion of an accredited course of instruction for a physician's assistant or nurse... to work in the purser's office. (3) Senior assistant purser. Six months of service aboard vessels performing duties relating to work in purser's office. (4) Junior assistant purser. Previous experience not...

  8. 46 CFR 11.807 - Experience requirements for registry.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... assistant. Successful completion of an accredited course of instruction for a physician's assistant or nurse... to work in the purser's office. (3) Senior assistant purser. Six months of service aboard vessels performing duties relating to work in purser's office. (4) Junior assistant purser. Previous experience not...

  9. 46 CFR 11.807 - Experience requirements for registry.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... assistant. Successful completion of an accredited course of instruction for a physician's assistant or nurse... to work in the purser's office. (3) Senior assistant purser. Six months of service aboard vessels performing duties relating to work in purser's office. (4) Junior assistant purser. Previous experience not...

  10. 46 CFR 11.807 - Experience requirements for registry.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... assistant. Successful completion of an accredited course of instruction for a physician's assistant or nurse... to work in the purser's office. (3) Senior assistant purser. Six months of service aboard vessels performing duties relating to work in purser's office. (4) Junior assistant purser. Previous experience not...

  11. Mental health emergencies.

    PubMed

    Skinner, Anita

    I gained experience of psychiatric assessment in previous roles when working in a secure psychiatric ward and within the prison service. Although I have often performed mental state assessments and assessments of suicidal intent as part of my work, I read the CPD article to refresh my knowledge in this area.

  12. Some Prerequisites in Learning to Solve Figural Analogy Problems.

    ERIC Educational Resources Information Center

    Wagner, James

    A series of three experiments was conducted for the purposes of (1) clarifying problems of previous research on the relationship between working memory capacity and performance on figural analogy tasks, and (2) exploring developmental issues concerning executive strategies, working memory capacity, and perceptual processing. Directly manipulating…

  13. How Need for Cognition Affects the Formation of Performance Expectancies at School

    ERIC Educational Resources Information Center

    Dickhauser, Oliver; Reinhard, Marc-Andre

    2009-01-01

    Individuals with low Need for Cognition (NFC) have been found to process information using a peripheral route compared to individuals higher in NFC. These differences affect the formation of performance expectancies. Based on previous work demonstrating that the formation of performance expectancies can be understood as an information processing…

  14. 77 FR 4654 - Senior Community Service Employment Program; Final Rule, Additional Indicator on Volunteer Work

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-31

    ... rule amends our regulations regarding Performance Accountability for title V of the Older Americans Act... on September 1, 2010. 75 FR 53786. Previously, an interim final rule (IFR) on performance measures... performance through regulation. OAA Sec. 513(b)(3). As established in the SCSEP Final Rule published September...

  15. Visionary Leadership

    DTIC Science & Technology

    1993-06-04

    SHARED PURPOSE + EMPOWERED PEOPLE + APPROPRIATE ORGANIZATIONAL CHANGES + STRATEGIC THINKING a SUCCESSFUL VISIONARY LEADERSHIP34 Nanus stated that the...energized and motivated people , acknowledged work well done, counseled and developed subordinates, always set the example, and listened to the soldiers...been given their positions of responsibility based on their previous succeses and their potential for future performance. Of course, previous successes

  16. Verbal working memory performance correlates with regional white matter structures in the frontoparietal regions.

    PubMed

    Takeuchi, Hikaru; Taki, Yasuyuki; Sassa, Yuko; Hashizume, Hiroshi; Sekiguchi, Atsushi; Fukushima, Ai; Kawashima, Ryuta

    2011-10-01

    Working memory is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. Previous imaging studies have suggested that the frontoparietal regions are activated during working memory tasks; a putative association between the structure of the frontoparietal regions and working memory performance has been suggested based on the analysis of individuals with varying pathologies. This study aimed to identify correlations between white matter and individual differences in verbal working memory performance in normal young subjects. We performed voxel-based morphometry (VBM) analyses using T1-weighted structural images as well as voxel-based analyses of fractional anisotropy (FA) using diffusion tensor imaging. Using the letter span task, we measured verbal working memory performance in normal young adult men and women (mean age, 21.7 years, SD=1.44; 42 men and 13 women). We observed positive correlations between working memory performance and regional white matter volume (rWMV) in the frontoparietal regions. In addition, FA was found to be positively correlated with verbal working memory performance in a white matter region adjacent to the right precuneus. These regions are consistently recruited by working memory. Our findings suggest that, among normal young subjects, verbal working memory performance is associated with various regions that are recruited during working memory tasks, and this association is not limited to specific parts of the working memory network. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. CYCLOPS-3 System Research.

    ERIC Educational Resources Information Center

    Marill, Thomas; And Others

    The aim of the CYCLOPS Project research is the development of techniques for allowing computers to perform visual scene analysis, pre-processing of visual imagery, and perceptual learning. Work on scene analysis and learning has previously been described. The present report deals with research on pre-processing and with further work on scene…

  18. Performance analysis of the toroidal field ITER production conductors

    NASA Astrophysics Data System (ADS)

    Breschi, M.; Macioce, D.; Devred, A.

    2017-05-01

    The production of the superconducting cables for the toroidal field (TF) magnets of the ITER machine has recently been completed at the manufacturing companies selected during the previous qualification phase. The quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers include performance tests of several conductor samples from selected unit lengths. The short full-size samples (4 m long) were subjected to DC and AC tests in the SULTAN facility at CRPP in Villigen, Switzerland. In a previous work the results of the tests of the conductor performance qualification samples were reported. This work reports the analyses of the results of the tests of the production conductor samples. The results reported here concern the values of current sharing temperature, critical current, effective strain and n-value from the DC tests and the energy dissipated per cycle from the AC loss tests. A detailed comparison is also presented between the performance of the conductors and that of their constituting strands.

  19. Disruptions of working memory and inhibition mediate the association between exposure to institutionalization and symptoms of attention deficit hyperactivity disorder.

    PubMed

    Tibu, F; Sheridan, M A; McLaughlin, K A; Nelson, C A; Fox, N A; Zeanah, C H

    2016-02-01

    Young children raised in institutions are exposed to extreme psychosocial deprivation that is associated with elevated risk for psychopathology and other adverse developmental outcomes. The prevalence of attention deficit hyperactivity disorder (ADHD) is particularly high in previously institutionalized children, yet the mechanisms underlying this association are poorly understood. We investigated whether deficits in executive functioning (EF) explain the link between institutionalization and ADHD. A sample of 136 children (aged 6-30 months) was recruited from institutions in Bucharest, Romania, and 72 never institutionalized community children matched for age and gender were recruited through general practitioners' offices. At 8 years of age, children's performance on a number of EF components (working memory, response inhibition and planning) was evaluated. Teachers completed the Health and Behavior Questionnaire, which assesses two core features of ADHD, inattention and impulsivity. Children with history of institutionalization had higher inattention and impulsivity than community controls, and exhibited worse performance on working memory, response inhibition and planning tasks. Lower performances on working memory and response inhibition, but not planning, partially mediated the association between early institutionalization and inattention and impulsivity symptom scales at age 8 years. Institutionalization was associated with decreased EF performance and increased ADHD symptoms. Deficits in working memory and response inhibition were specific mechanisms leading to ADHD in previously institutionalized children. These findings suggest that interventions that foster the development of EF might reduce risk for psychiatric problems in children exposed to early deprivation.

  20. Do workaholism and work engagement predict employee well-being and performance in opposite directions?

    PubMed

    Shimazu, Akihito; Schaufeli, Wilmar B; Kubota, Kazumi; Kawakami, Norito

    2012-01-01

    This study investigated the distinctiveness between workaholism and work engagement by examining their longitudinal relationships (measurement interval=7 months) with well-being and performance in a sample of 1,967 Japanese employees from various occupations. Based on a previous cross-sectional study (Shimazu & Schaufeli, 2009), we expected that workaholism predicts future unwell-being (i.e., high ill-health and low life satisfaction) and poor job performance, whereas work engagement predicts future well-being (i.e., low ill-health and high life satisfaction) and superior job performance. T1-T2 changes in ill-health, life satisfaction and job performance were measured as residual scores that were then included in the structural equation model. Results showed that workaholism and work engagement were weakly and positively related to each other. In addition, workaholism was related to an increase in ill-health and to a decrease in life satisfaction. In contrast, work engagement was related to a decrease in ill-health and to increases in both life satisfaction and job performance. These findings suggest that workaholism and work engagement are two different kinds of concepts that are oppositely related to well-being and performance.

  1. What works best for whom? An exploratory, subgroup analysis in a randomized, controlled trial on the effectiveness of a workplace intervention in low back pain patients on return to work.

    PubMed

    Steenstra, Ivan A; Knol, Dirk L; Bongers, Paulien M; Anema, Johannes R; van Mechelen, Willem; de Vet, Henrica C W

    2009-05-20

    Exploratory subgroup analysis in a randomized controlled trial (RCT). To detect possible moderators in the effectiveness of a workplace intervention in a population of workers with sick leave due to sub acute nonspecific low back pain. In a recently published RCT, a workplace intervention was effective on return to work, compared to usual care. Examining the heterogeneity of effect sizes within the population in this RCT (n = 196) can lead to information on the effectiveness of the intervention in subgroups of patients. A subgroup analysis was performed by adding interaction terms to the statistical model. Before analysis the following possible moderators for treatment were identified: age, gender, pain, functional status, heavy work, and sick leave in the previous 12 months. Cox regression analyses were performed and survival curves were plotted. The interaction (P = 0.02) between age (dichotomized at the median value) and the workplace intervention indicates a modifying effect. The workplace intervention is more effective for workers > or =44 years (HR, 95% CI = 2.5, [1.6, 4.1] vs. 1.2 [0.8, 1.8] for workers <44 years old). The interaction between sick leave in the previous 12 months and the workplace intervention is significant (P = 0.02). The intervention is more effective for workers with previous sick leave (HR, 95% CI = 2.8 [1.7, 4.9] vs. 1.3 [0.8, 2.0]). A modifying effect of gender, heavy work, and pain score and functional status on the effectiveness of this intervention was not found. The findings from these exploratory analyses should be tested in future RCTs. This workplace intervention seems very suitable for return to work of older workers and workers with previous sick leave. Gender, perceived heavy work, and baseline scores in pain and functional status should not be a basis for assignment to this intervention.

  2. THE RELATIONSHIP OF REACTIVE INHIBITION AND SCHOOL ACHIEVEMENT--THEORY, RESEARCH, AND IMPLICATIONS.

    ERIC Educational Resources Information Center

    OTTO, WAYNE

    THE RELATIONSHIP OF REACTIVE INHIBITION TO TEST PERFORMANCE AND TO ACHIEVEMENT IN READING, SPELLING, AND HANDWRITING WAS STUDIED. IN THIS STUDY, AS IN PREVIOUS WORK DONE BY HALL (1943), REACTIVE INHIBITION IS DEFINED AS THE ACCUMULATION OF A GRADUAL DECREASE IN THE LEVEL OF PERFORMANCE THAT RESULTS FROM THE PERFORMANCE ITSELF. WHEN GIVEN A LOW…

  3. Is functional integration of resting state brain networks an unspecific biomarker for working memory performance?

    PubMed

    Alavash, Mohsen; Doebler, Philipp; Holling, Heinz; Thiel, Christiane M; Gießing, Carsten

    2015-03-01

    Is there one optimal topology of functional brain networks at rest from which our cognitive performance would profit? Previous studies suggest that functional integration of resting state brain networks is an important biomarker for cognitive performance. However, it is still unknown whether higher network integration is an unspecific predictor for good cognitive performance or, alternatively, whether specific network organization during rest predicts only specific cognitive abilities. Here, we investigated the relationship between network integration at rest and cognitive performance using two tasks that measured different aspects of working memory; one task assessed visual-spatial and the other numerical working memory. Network clustering, modularity and efficiency were computed to capture network integration on different levels of network organization, and to statistically compare their correlations with the performance in each working memory test. The results revealed that each working memory aspect profits from a different resting state topology, and the tests showed significantly different correlations with each of the measures of network integration. While higher global network integration and modularity predicted significantly better performance in visual-spatial working memory, both measures showed no significant correlation with numerical working memory performance. In contrast, numerical working memory was superior in subjects with highly clustered brain networks, predominantly in the intraparietal sulcus, a core brain region of the working memory network. Our findings suggest that a specific balance between local and global functional integration of resting state brain networks facilitates special aspects of cognitive performance. In the context of working memory, while visual-spatial performance is facilitated by globally integrated functional resting state brain networks, numerical working memory profits from increased capacities for local processing, especially in brain regions involved in working memory performance. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Effect of air velocity on laying hen performance and egg quality

    USDA-ARS?s Scientific Manuscript database

    Increasing convective cooling can improve performance and thermal comfort of commercial poultry when weather or system design limit cooling through other means such as evaporative cooling. Previous work in young hens showed increased egg production rate as feed intake is maintained under heat stres...

  5. A mixed-methods study of interprofessional learning of resuscitation skills.

    PubMed

    Bradley, Paul; Cooper, Simon; Duncan, Fiona

    2009-09-01

    This study aimed to identify the effects of interprofessional resuscitation skills teaching on medical and nursing students' attitudes, leadership, team-working and performance skills. Year 2 medical and nursing students learned resuscitation skills in uniprofessional or interprofessional settings, prior to undergoing observational ratings of video-recorded leadership, teamwork and skills performance and subsequent focus group interviews. The Readiness for Interprofessional Learning Scale (RIPLS) was administered pre- and post-intervention and again 3-4 months later. There was no significant difference between interprofessional and uniprofessional teams for leadership, team dynamics or resuscitation tasks performance. Gender, previous interprofessional learning experience, professional background and previous leadership experience had no significant effect. Interview analysis showed broad support for interprofessional education (IPE) matched to clinical reality with perceived benefits for teamwork, communication and improved understanding of roles and perspectives. Concerns included inappropriate role adoption, hierarchy issues, professional identity and the timing of IPE episodes. The RIPLS subscales for professional identity and team-working increased significantly post-intervention for interprofessional groups but returned to pre-test levels by 3-4 months. However, interviews showed interprofessional groups retained a 'residual positivity' towards IPE, more so than uniprofessional groups. An intervention based on common, relevant, shared learning outcomes set in a realistic educational context can work with students who have differing levels of previous IPE and skills training experience. Qualitatively, positive attitudes outlast quantitative changes measured using the RIPLS. Further quantitative and qualitative work is required to examine other domains of learning, the timing of interventions and impact on attitudes towards IPE.

  6. Studies on Vapor Adsorption Systems

    NASA Technical Reports Server (NTRS)

    Shamsundar, N.; Ramotowski, M.

    1998-01-01

    The project consisted of performing experiments on single and dual bed vapor adsorption systems, thermodynamic cycle optimization, and thermal modeling. The work was described in a technical paper that appeared in conference proceedings and a Master's thesis, which were previously submitted to NASA. The present report describes some additional thermal modeling work done subsequently, and includes listings of computer codes developed during the project. Recommendations for future work are provided.

  7. Tax Professional Internships and Subsequent Professional Performance

    ERIC Educational Resources Information Center

    Siegel, Philip H.; Blackwood, B. J.; Landy, Sharon D.

    2010-01-01

    How do internships influence the socialization and performance of accounting students employed in the tax department of a CPA firm? Previous research on accounting internships primarily focuses on auditing personnel. There is evidence in the literature that indicates audit and tax professionals have different work cultures. This paper examines the…

  8. Dynamic Cognitive Tracing: Towards Unified Discovery of Student and Cognitive Models

    ERIC Educational Resources Information Center

    Gonzalez-Brenes, Jose P.; Mostow, Jack

    2012-01-01

    This work describes a unified approach to two problems previously addressed separately in Intelligent Tutoring Systems: (i) Cognitive Modeling, which factorizes problem solving steps into the latent set of skills required to perform them; and (ii) Student Modeling, which infers students' learning by observing student performance. The practical…

  9. Spatial Working Memory Performance and fMRI Activation Interactions in Abstinent Adolescent Marijuana Users

    PubMed Central

    Padula, Claudia B.; Schweinsburg, Alecia D.; Tapert, Susan F.

    2008-01-01

    Previous studies have suggested neural disruption and reorganization in adult marijuana users. However, it remains unclear whether these effects persist in adolescents after 28 days of abstinence and, if they do, what Performance × Brain Response interactions occur. Adolescent marijuana users (n = 17) and controls (n = 17) aged 16–18 years were recruited from local schools. Functional magnetic resonance imaging data were collected after 28 days’ monitored abstinence as participants performed a spatial working memory task. Marijuana users show Performance × Brain Response interactions in the bilateral temporal lobes, left anterior cingulate, left parahippocampal gyrus, and right thalamus (clusters ≥ 1358 μl; p <.05), although groups do not differ on behavioral measures of task performance. Marijuana users show differences in brain response to a spatial working memory task despite adequate performance, suggesting a different approach to the task via altered neural pathways. PMID:18072830

  10. Rotor-Bearing Dynamics Technology Design Guide. Part 8. A computerized Data Retrieval System for Fluid Film Bearings

    DTIC Science & Technology

    1980-10-01

    AFAPL-TR-78-6 ’: Part Vill (U ROTOR -BEARING DYNAMICS - TECHNOLOGY DESIGN GUIDE ¢ Part Vil A Comput eri eval Syteftor Fluid Film Bearings SHAKER...Protection," Task 304806, "Aerospace Lubrication," Work Unit 30480685, " Rotor -Bearing Dynamics Design." The work reported herein was performed during the...the previous issue of the Rotor -Bearing Dynamics Technology Design Guide, - one volume dealt with the calculation of performance parameters and pertur

  11. Central executive involvement in children's spatial memory.

    PubMed

    Ang, Su Yin; Lee, Kerry

    2008-11-01

    Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.

  12. Articulatory rehearsal in verbal working memory: a possible neurocognitive endophenotype that differentiates between schizophrenia and schizoaffective disorder.

    PubMed

    Gruber, Oliver; Gruber, Eva; Falkai, Peter

    2006-09-11

    Recent fMRI studies have identified brain systems underlying different components of working memory in healthy individuals. The aim of this study was to compare the functional integrity of these neural networks in terms of behavioural performance in patients with schizophrenia, schizoaffective disorder and healthy controls. In order to detect specific working memory deficits based on dysfunctions of underlying brain circuits we used the same verbal and visuospatial Sternberg item-recognition tasks as in previous neuroimaging studies. Clinical and performance data from matched groups consisting of 14 subjects each were statistically analyzed. Schizophrenic patients exhibited pronounced impairments of both verbal and visuospatial working memory, whereas verbal working memory performance was preserved in schizoaffective patients. The findings provide first evidence that dysfunction of a brain system subserving articulatory rehearsal could represent a biological marker which differentiates between schizophrenia and schizoaffective disorder.

  13. 48 CFR 1419.705-3 - Preparing the solicitation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... known to offer significant subcontracting opportunities for small, small disadvantaged, and women-owned businesses or which include work previously performed by a small business. When used, this factor must be...

  14. 48 CFR 1419.705-3 - Preparing the solicitation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... known to offer significant subcontracting opportunities for small, small disadvantaged, and women-owned businesses or which include work previously performed by a small business. When used, this factor must be...

  15. Fiber-Optic Sensing for In-Space Inspection

    NASA Technical Reports Server (NTRS)

    Pena, Francisco; Richards, W. Lance; Piazza, Anthony; Parker, Allen R.; Hudson, Larry D.

    2014-01-01

    This presentation provides examples of fiber optic sensing technology development activities performed at NASA Armstrong. Examples of current and previous work that support in-space inspection techniques and methodologies are highlighted.

  16. Shock compression response of cold-rolled Ni/Al multilayer composites

    DOE PAGES

    Specht, Paul E.; Weihs, Timothy P.; Thadhani, Naresh N.

    2017-01-06

    Uniaxial strain, plate-on-plate impact experiments were performed on cold-rolled Ni/Al multilayer composites and the resulting Hugoniot was determined through time-resolved measurements combined with impedance matching. The experimental Hugoniot agreed with that previously predicted by two dimensional (2D) meso-scale calculations. Additional 2D meso-scale simulations were performed using the same computational method as the prior study to reproduce the experimentally measured free surface velocities and stress profiles. Finally, these simulations accurately replicated the experimental profiles, providing additional validation for the previous computational work.

  17. Lowered performance in working memory and attentional sub-processes are most prominent in multi-domain amnestic mild cognitive impairment subtypes.

    PubMed

    Klekociuk, Shannon Z; Summers, Mathew J

    2014-03-01

    Research suggests that working memory and attention deficits may be present in mild cognitive impairment (MCI). However, the functional status of these domains within revised MCI subtypes remains unclear, particularly because previous studies have examined these cognitive domains with the same tests that were used to classify MCI subtypes. The aim of this study was to examine working memory and attention function in MCI subtypes on a battery of neuropsychological tests that were distinct from those used to classify MCI subtypes A total of 122 adults aged 60-90 years were classified at baseline as amnestic MCI, non-amnestic MCI, and multi-domain amnestic (a-MCI+). The attentional and working memory capacity of participants was examined using a battery of tests distinct from those used to classify MCI at screening. The a-MCI+ group demonstrated the poorest performance on all working memory tasks and specific sub-processes of attention. The non-amnestic MCI group had lowered performance on visual span and complex sustained attention only. There was no evidence of either attentional or working memory impairment in the amnestic MCI participants. When MCI cohorts are assessed on measures distinct from those used at classification, a-MCI+ subjects had the most compromised working memory and attention function. These results support previous findings that suggest a-MCI+ more closely resembles early stage Alzheimer's disease and those with a-MCI+ may be at increased rate of future cognitive decline compared to those with other MCI subtypes. © 2014 The Authors. Psychogeriatrics © 2014 Japanese Psychogeriatric Society.

  18. Implementing Molecular Dynamics on Hybrid High Performance Computers - Particle-Particle Particle-Mesh

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

    Brown, W Michael; Kohlmeyer, Axel; Plimpton, Steven J

    The use of accelerators such as graphics processing units (GPUs) has become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high-performance computers, machines with nodes containing more than one type of floating-point processor (e.g. CPU and GPU), are now becoming more prevalent due to these advantages. In this paper, we present a continuation of previous work implementing algorithms for using accelerators into the LAMMPS molecular dynamics software for distributed memory parallel hybrid machines. In our previous work, we focused on acceleration for short-range models with anmore » approach intended to harness the processing power of both the accelerator and (multi-core) CPUs. To augment the existing implementations, we present an efficient implementation of long-range electrostatic force calculation for molecular dynamics. Specifically, we present an implementation of the particle-particle particle-mesh method based on the work by Harvey and De Fabritiis. We present benchmark results on the Keeneland InfiniBand GPU cluster. We provide a performance comparison of the same kernels compiled with both CUDA and OpenCL. We discuss limitations to parallel efficiency and future directions for improving performance on hybrid or heterogeneous computers.« less

  19. Ego Depletion Does Not Interfere With Working Memory Performance.

    PubMed

    Singh, Ranjit K; Göritz, Anja S

    2018-01-01

    Ego depletion happens if exerting self-control reduces a person's capacity to subsequently control themselves. Previous research has suggested that ego depletion not only interferes with subsequent self-control but also with working memory. However, recent meta-analytical evidence casts doubt onto this. The present study tackles the question if ego depletion does interfere with working memory performance. We induced ego depletion in two ways: using an e-crossing task and using a Stroop task. We then measured working memory performance using the letter-number sequencing task. There was no evidence of ego depletion interfering with working memory performance. Several aspects of our study render this null finding highly robust. We had a large and heterogeneous sample of N = 1,385, which provided sufficient power. We deployed established depletion tasks from two task families (e-crossing task and Stroop), thus making it less likely that the null finding is due to a specific depletion paradigm. We derived several performance scores from the working memory task and ran different analyses to maximize the chances of finding an effect. Lastly, we controlled for two potential moderators, the implicit theories about willpower and dispositional self-control capacity, to ensure that a possible effect on working memory is not obscured by an interaction effect. In sum, this experiment strengthens the position that ego depletion works but does not affect working memory performance.

  20. Ego Depletion Does Not Interfere With Working Memory Performance

    PubMed Central

    Singh, Ranjit K.; Göritz, Anja S.

    2018-01-01

    Ego depletion happens if exerting self-control reduces a person’s capacity to subsequently control themselves. Previous research has suggested that ego depletion not only interferes with subsequent self-control but also with working memory. However, recent meta-analytical evidence casts doubt onto this. The present study tackles the question if ego depletion does interfere with working memory performance. We induced ego depletion in two ways: using an e-crossing task and using a Stroop task. We then measured working memory performance using the letter-number sequencing task. There was no evidence of ego depletion interfering with working memory performance. Several aspects of our study render this null finding highly robust. We had a large and heterogeneous sample of N = 1,385, which provided sufficient power. We deployed established depletion tasks from two task families (e-crossing task and Stroop), thus making it less likely that the null finding is due to a specific depletion paradigm. We derived several performance scores from the working memory task and ran different analyses to maximize the chances of finding an effect. Lastly, we controlled for two potential moderators, the implicit theories about willpower and dispositional self-control capacity, to ensure that a possible effect on working memory is not obscured by an interaction effect. In sum, this experiment strengthens the position that ego depletion works but does not affect working memory performance. PMID:29706923

  1. Do Women Profit from the Fact That They Perform the Same Sort of Work as Men?

    ERIC Educational Resources Information Center

    Kauppinen-Toropainen, Kaisa

    The Finnish labor market is sharply segregated by sex. Previous research has shown the work of women to be inferior to that of men in that the work of women is less autonomous, allows less freedom for self-regulation and self-determination, is more restricted in space and time, and is more monotonous. This study sought to determine whether the…

  2. Why Is Working Memory Performance Unstable? A Review of 21 Factors

    PubMed Central

    Blasiman, Rachael N.; Was, Christopher A.

    2018-01-01

    In this paper, we systematically reviewed twenty-one factors that have been shown to either vary with or influence performance on working memory (WM) tasks. Specifically, we review previous work on the influence of intelligence, gender, age, personality, mental illnesses/medical conditions, dieting, craving, stress/anxiety, emotion/motivation, stereotype threat, temperature, mindfulness training, practice, bilingualism, musical training, altitude/hypoxia, sleep, exercise, diet, psychoactive substances, and brain stimulation on WM performance. In addition to a review of the literature, we suggest several frameworks for classifying these factors, identify shared mechanisms between several variables, and suggest areas requiring further investigation. This review critically examines the breadth of research investigating WM while synthesizing the results across related subfields in psychology. PMID:29899806

  3. Setting visual pre-placement testing in a technology manufacturing environment.

    PubMed

    Gowan, Nancy J

    2014-01-01

    Every day we use our eyes to perform activities of daily living and work. Aging changes as well as health conditions can impact an individual's visual function, making it more difficult to accurately perform work activities. Occupational therapists work closely with optometrists and employers to develop ways to accommodate for these changes so that the employee can continue to perform the work tasks. This manuscript outlines a case study of systematically developing visual demands analyses and pre-placement vision screening assessment protocols for individuals completing quality inspection positions. When the vision screening was completed, it was discovered that over 20% of the employees had visual deficits that were correctable. This screening process yielded improved quality results but also identification of previously undetected visual deficits. Further development of vision screening in the workplace is supported.

  4. Informal Peer-Assisted Learning Groups Did Not Lead to Better Performance of Saudi Dental Students.

    PubMed

    AbdelSalam, Maha; El Tantawi, Maha; Al-Ansari, Asim; AlAgl, Adel; Al-Harbi, Fahad

    2017-01-01

    To describe peer-assisted learning (PAL) groups formed by dental undergraduate students in a biomedical course and to investigate the association of individual and group characteristics with academic performance. In 2015, 92 fourth-year students (43 males and 49 females) in the College of Dentistry, University of Dammam, Saudi Arabia, were invited to form PAL groups to study a unit of a biomedical course. An examination was used to assess their knowledge after 2 weeks. In addition, a questionnaire and social network analysis were used to investigate (1) individual student attributes: gender, role, subject matter knowledge, grade in previous year, teaming with friends, previous communication with teammates, and content discussion, and (2) group attributes: group teacher's previous grade, number of colleagues with whom a student connected, teaming with friends, similarity of teammates' previous grades, and teacher having higher previous grades than other teammates. Regression analysis was used to assess the association of examination scores with individual and group attributes. The response rate was 80.4% (74 students: 36 males and 38 females). Students who previously scored grades A and B had higher examination scores than students with grades C/less (regression coefficient = 18.50 and 13.39) within the groups. Higher scores were not associated with working in groups including friends only (regression coefficient = 1.17) or when all students had similar previous grades (regression coefficient = 0.85). Students with previous high grades benefited to a greater extent from working in PAL groups. Similarity of teammates in PAL groups was not associated with better scores. © 2017 S. Karger AG, Basel.

  5. The Problem of Simplification: Think-Tanks, Recipes, Equity and "Turning around Low-Performing Schools"

    ERIC Educational Resources Information Center

    Loughland, Tony; Thompson, Greg

    2016-01-01

    Non-government actors such as think-tanks are playing an important role in Australian policy work. As governments increasingly outsource policy work previously done by education departments and academics to these new policy actors, more think-tanks have emerged that represent a wide range of political views and ideological positions. This paper…

  6. Semiannual status report

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The work performed in the previous six months can be divided into three main cases: (1) transmission of images over local area networks (LAN's); (2) coding of color mapped (pseudo-color) images; and (3) low rate video coding. A brief overview of the work done in the first two areas is presented. The third item is reported in somewhat more detail.

  7. Comparison of the Nature of Work Performed: Southern Land-Grant University Colleges of Agriculture Alumni.

    ERIC Educational Resources Information Center

    Zekeri, Andrew A.

    American agriculture is seriously threatened by growing shortages of highly qualified scientists, managers, and technical professionals. This paper examines the work outcomes of agricultural college alumni who were previously surveyed as students in 1977. Questionnaires were completed by 1,917 graduates in agricultural majors at 1862 and 1890…

  8. Third Grade Students' Performance on Calculator and Calculator-Related Tasks. Technical Report No. 498.

    ERIC Educational Resources Information Center

    Weaver, J. Fred

    Refinements of work with calculator algorithms previously conducted by the author are reported. Work with "chaining" and the doing/undoing property in addition and subtraction was tested with 24 third-grade students. Results indicated the need for further instruction with both ideas. Students were able to manipulate the calculator keyboard, but…

  9. Dimension scaling effects on the yield sensitivity of HEMT digital circuits

    NASA Technical Reports Server (NTRS)

    Sarker, Jogendra C.; Purviance, John E.

    1992-01-01

    In our previous works, using a graphical tool, yield factor histograms, we studied the yield sensitivity of High Electron Mobility Transistors (HEMT) and HEMT circuit performance with the variation of process parameters. This work studies the scaling effects of process parameters on yield sensitivity of HEMT digital circuits. The results from two HEMT circuits are presented.

  10. Work Participation and Academic Performance: A Test of Alternative Propositions

    ERIC Educational Resources Information Center

    Bradley, Graham

    2006-01-01

    Increasing numbers of full-time university students mix their studies with paid employment. The current research examined the nature, extent and correlates of paid work amongst a sample of 246 university students. Approximately 85% of the sample reported having a paid job during semester, a figure that exceeds that found in previous studies. Five…

  11. Responses to Different Types of Inquiry Prompts: College Students' Discourse, Performance, and Perceptions of Group Work in an Engineering Class

    ERIC Educational Resources Information Center

    Balgopal, Meena M.; Casper, Anne Marie A.; Atadero, Rebecca A.; Rambo-Hernandez, Karen E.

    2017-01-01

    Working in small groups to solve problems is an instructional strategy that allows university students in science, technology, engineering, and mathematics disciplines the opportunity to practice interpersonal and professional skills while gaining and applying discipline-specific content knowledge. Previous research indicates that not all group…

  12. Math anxiety differentially affects WAIS-IV arithmetic performance in undergraduates.

    PubMed

    Buelow, Melissa T; Frakey, Laura L

    2013-06-01

    Previous research has shown that math anxiety can influence the math performance level; however, to date, it is unknown whether math anxiety influences performance on working memory tasks during neuropsychological evaluation. In the present study, 172 undergraduate students completed measures of math achievement (the Math Computation subtest from the Wide Range Achievement Test-IV), math anxiety (the Math Anxiety Rating Scale-Revised), general test anxiety (from the Adult Manifest Anxiety Scale-College version), and the three Working Memory Index tasks from the Wechsler Adult Intelligence Scale-IV Edition (WAIS-IV; Digit Span [DS], Arithmetic, Letter-Number Sequencing [LNS]). Results indicated that math anxiety predicted performance on Arithmetic, but not DS or LNS, above and beyond the effects of gender, general test anxiety, and math performance level. Our findings suggest that math anxiety can negatively influence WAIS-IV working memory subtest scores. Implications for clinical practice include the utilization of LNS in individuals expressing high math anxiety.

  13. Exploring the Relationship Between Working Memory, Compressor Speed, and Background Noise Characteristics.

    PubMed

    Ohlenforst, Barbara; Souza, Pamela E; MacDonald, Ewen N

    2016-01-01

    Previous work has shown that individuals with lower working memory demonstrate reduced intelligibility for speech processed with fast-acting compression amplification. This relationship has been noted in fluctuating noise, but the extent of noise modulation that must be present to elicit such an effect is unknown. This study expanded on previous study by exploring the effect of background noise modulations in relation to compression speed and working memory ability, using a range of signal to noise ratios. Twenty-six older participants between ages 61 and 90 years were grouped by high or low working memory according to their performance on a reading span test. Speech intelligibility was measured for low-context sentences presented in background noise, where the noise varied in the extent of amplitude modulation. Simulated fast- or slow-acting compression amplification combined with individual frequency-gain shaping was applied to compensate for the individual's hearing loss. Better speech intelligibility scores were observed for participants with high working memory when fast compression was applied than when slow compression was applied. The low working memory group behaved in the opposite way and performed better under slow compression compared with fast compression. There was also a significant effect of the extent of amplitude modulation in the background noise, such that the magnitude of the score difference (fast versus slow compression) depended on the number of talkers in the background noise. The presented signal to noise ratios were not a significant factor on the measured intelligibility performance. In agreement with earlier research, high working memory allowed better speech intelligibility when fast compression was applied in modulated background noise. In the present experiment, that effect was present regardless of the extent of background noise modulation.

  14. Performance Evaluation of a Firm Real-Time DataBase System

    DTIC Science & Technology

    1995-01-01

    after its deadline has passed. StarBase differs from previous real-time database work in that a) it relies on a real - time operating system which...StarBase, running on a real - time operating system kernel, RT-Mach. We discuss how performance was evaluated in StarBase using the StarBase workload

  15. Molecular Mechanisms Underlying Individual Differences in Response to Stress in a Previously Validated Animal Model of PTSD

    DTIC Science & Technology

    2012-04-01

    CONTRACTING ORGANIZATION: Bronx Veterans Medical Research Foundation, Inc... Bronx , NY 10468-3904 REPORT DATE: April 2012 TYPE OF REPORT: Final PREPARED FOR: U.S. Army...WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Bronx Veterans Medical Research

  16. Cognitive Reflection and the Diligent Worker: An Experimental Study of Millennials

    PubMed Central

    Corgnet, Brice; Hernán Gonzalez, Roberto; Mateo, Ricardo

    2015-01-01

    Recent studies have shown that despite crucially needing the creative talent of millennials (people born after 1980) organizations have been reluctant to hire young workers because of their supposed lack of diligence. We propose to help resolve this dilemma by studying the determinants of task performance and shirking behaviors of millennials in a laboratory work environment. We find that cognitive ability is a good predictor of task performance in line with previous literature. In contrast with previous research, personality traits do not consistently predict either task performance or shirking behaviors. Shirking behaviors, as measured by the time participants spent browsing the internet for non-work purposes (Cyberloafing), were only explained by the performance on the Cognitive Reflection Test (CRT). This finding echoes recent research in cognitive psychology according to which conventional measures of cognitive ability only assess a narrow concept of rational thinking (the algorithmic mind) that fails to capture individuals’ capacity to reflect and control their impulses. Our findings suggest that hiring diligent millennials relies on the use of novel cognitive measures such as CRT in lieu of standard personality and intelligence tests. PMID:26545244

  17. Cognitive Reflection and the Diligent Worker: An Experimental Study of Millennials.

    PubMed

    Corgnet, Brice; Hernán Gonzalez, Roberto; Mateo, Ricardo

    2015-01-01

    Recent studies have shown that despite crucially needing the creative talent of millennials (people born after 1980) organizations have been reluctant to hire young workers because of their supposed lack of diligence. We propose to help resolve this dilemma by studying the determinants of task performance and shirking behaviors of millennials in a laboratory work environment. We find that cognitive ability is a good predictor of task performance in line with previous literature. In contrast with previous research, personality traits do not consistently predict either task performance or shirking behaviors. Shirking behaviors, as measured by the time participants spent browsing the internet for non-work purposes (Cyberloafing), were only explained by the performance on the Cognitive Reflection Test (CRT). This finding echoes recent research in cognitive psychology according to which conventional measures of cognitive ability only assess a narrow concept of rational thinking (the algorithmic mind) that fails to capture individuals' capacity to reflect and control their impulses. Our findings suggest that hiring diligent millennials relies on the use of novel cognitive measures such as CRT in lieu of standard personality and intelligence tests.

  18. Spatial-Sequential Working Memory in Younger and Older Adults: Age Predicts Backward Recall Performance within Both Age Groups

    PubMed Central

    Brown, Louise A.

    2016-01-01

    Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18–40 years) and older (64–85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale – Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts backward spatial span performance across the adult lifespan, within both younger and older adulthood. PMID:27757096

  19. Spatial-Sequential Working Memory in Younger and Older Adults: Age Predicts Backward Recall Performance within Both Age Groups.

    PubMed

    Brown, Louise A

    2016-01-01

    Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18-40 years) and older (64-85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale - Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts backward spatial span performance across the adult lifespan, within both younger and older adulthood.

  20. Why Study Time Does Not Predict Grade Point Average across College Students: Implications of Deliberate Practice for Academic Performance

    ERIC Educational Resources Information Center

    Plant, E. Ashby; Ericsson, K. Anders; Hill, Len; Asberg, Kia

    2005-01-01

    The current work draws upon the theoretical framework of deliberate practice in order to clarify why the amount of study by college students is a poor predictor of academic performance. A model was proposed where performance in college, both cumulatively and for a current semester, was jointly determined by previous knowledge and skills as well as…

  1. Analysis of Network Clustering Algorithms and Cluster Quality Metrics at Scale

    PubMed Central

    Kobourov, Stephen; Gallant, Mike; Börner, Katy

    2016-01-01

    Overview Notions of community quality underlie the clustering of networks. While studies surrounding network clustering are increasingly common, a precise understanding of the realtionship between different cluster quality metrics is unknown. In this paper, we examine the relationship between stand-alone cluster quality metrics and information recovery metrics through a rigorous analysis of four widely-used network clustering algorithms—Louvain, Infomap, label propagation, and smart local moving. We consider the stand-alone quality metrics of modularity, conductance, and coverage, and we consider the information recovery metrics of adjusted Rand score, normalized mutual information, and a variant of normalized mutual information used in previous work. Our study includes both synthetic graphs and empirical data sets of sizes varying from 1,000 to 1,000,000 nodes. Cluster Quality Metrics We find significant differences among the results of the different cluster quality metrics. For example, clustering algorithms can return a value of 0.4 out of 1 on modularity but score 0 out of 1 on information recovery. We find conductance, though imperfect, to be the stand-alone quality metric that best indicates performance on the information recovery metrics. Additionally, our study shows that the variant of normalized mutual information used in previous work cannot be assumed to differ only slightly from traditional normalized mutual information. Network Clustering Algorithms Smart local moving is the overall best performing algorithm in our study, but discrepancies between cluster evaluation metrics prevent us from declaring it an absolutely superior algorithm. Interestingly, Louvain performed better than Infomap in nearly all the tests in our study, contradicting the results of previous work in which Infomap was superior to Louvain. We find that although label propagation performs poorly when clusters are less clearly defined, it scales efficiently and accurately to large graphs with well-defined clusters. PMID:27391786

  2. Analysis of Network Clustering Algorithms and Cluster Quality Metrics at Scale.

    PubMed

    Emmons, Scott; Kobourov, Stephen; Gallant, Mike; Börner, Katy

    2016-01-01

    Notions of community quality underlie the clustering of networks. While studies surrounding network clustering are increasingly common, a precise understanding of the realtionship between different cluster quality metrics is unknown. In this paper, we examine the relationship between stand-alone cluster quality metrics and information recovery metrics through a rigorous analysis of four widely-used network clustering algorithms-Louvain, Infomap, label propagation, and smart local moving. We consider the stand-alone quality metrics of modularity, conductance, and coverage, and we consider the information recovery metrics of adjusted Rand score, normalized mutual information, and a variant of normalized mutual information used in previous work. Our study includes both synthetic graphs and empirical data sets of sizes varying from 1,000 to 1,000,000 nodes. We find significant differences among the results of the different cluster quality metrics. For example, clustering algorithms can return a value of 0.4 out of 1 on modularity but score 0 out of 1 on information recovery. We find conductance, though imperfect, to be the stand-alone quality metric that best indicates performance on the information recovery metrics. Additionally, our study shows that the variant of normalized mutual information used in previous work cannot be assumed to differ only slightly from traditional normalized mutual information. Smart local moving is the overall best performing algorithm in our study, but discrepancies between cluster evaluation metrics prevent us from declaring it an absolutely superior algorithm. Interestingly, Louvain performed better than Infomap in nearly all the tests in our study, contradicting the results of previous work in which Infomap was superior to Louvain. We find that although label propagation performs poorly when clusters are less clearly defined, it scales efficiently and accurately to large graphs with well-defined clusters.

  3. What works with worked examples: Extending self-explanation and analogical comparison to synthesis problems

    NASA Astrophysics Data System (ADS)

    Badeau, Ryan; White, Daniel R.; Ibrahim, Bashirah; Ding, Lin; Heckler, Andrew F.

    2017-12-01

    The ability to solve physics problems that require multiple concepts from across the physics curriculum—"synthesis" problems—is often a goal of physics instruction. Three experiments were designed to evaluate the effectiveness of two instructional methods employing worked examples on student performance with synthesis problems; these instructional techniques, analogical comparison and self-explanation, have previously been studied primarily in the context of single-concept problems. Across three experiments with students from introductory calculus-based physics courses, both self-explanation and certain kinds of analogical comparison of worked examples significantly improved student performance on a target synthesis problem, with distinct improvements in recognition of the relevant concepts. More specifically, analogical comparison significantly improved student performance when the comparisons were invoked between worked synthesis examples. In contrast, similar comparisons between corresponding pairs of worked single-concept examples did not significantly improve performance. On a more complicated synthesis problem, self-explanation was significantly more effective than analogical comparison, potentially due to differences in how successfully students encoded the full structure of the worked examples. Finally, we find that the two techniques can be combined for additional benefit, with the trade-off of slightly more time on task.

  4. Caffeine Increases Anaerobic Work and Restores Cycling Performance following a Protocol Designed to Lower Endogenous Carbohydrate Availability

    PubMed Central

    Silva-Cavalcante, Marcos David; Correia-Oliveira, Carlos Rafaell; Santos, Ralmony Alcantara; Lopes-Silva, João Paulo; Lima, Hessel Marani; Bertuzzi, Romulo; Duarte, Marcos; Bishop, David John; Lima-Silva, Adriano Eduardo

    2013-01-01

    The purpose this study was to examine the effects of caffeine ingestion on performance and energy expenditure (anaerobic and aerobic contribution) during a 4-km cycling time trial (TT) performed after a carbohydrate (CHO) availability-lowering exercise protocol. After preliminary and familiarization trials, seven amateur cyclists performed three 4-km cycling TT in a double-blind, randomized and crossover design. The trials were performed either after no previous exercise (CON), or after a CHO availability-lowering exercise protocol (DEP) performed in the previous evening, followed by either placebo (DEP-PLA) or 5 mg.kg−1 of caffeine intake (DEP-CAF) 1 hour before the trial. Performance was reduced (−2.1%) in DEP-PLA vs CON (421.0±12.3 vs 412.4±9.7 s). However, performance was restored in DEP-CAF (404.6±17.1 s) compared with DEP-PLA, while no differences were found between DEP-CAF and CON. The anaerobic contribution was increased in DEP-CAF compared with both DEP-PLA and CON (67.4±14.91, 47. 3±14.6 and 55.3±14.0 W, respectively), and this was more pronounced in the first 3 km of the trial. Similarly, total anaerobic work was higher in DEP-CAF than in the other conditions. The integrated electromyographic activity, plasma lactate concentration, oxygen uptake, aerobic contribution and total aerobic work were not different between the conditions. The reduction in performance associated with low CHO availability is reversed with caffeine ingestion due to a higher anaerobic contribution, suggesting that caffeine could access an anaerobic “reserve” that is not used under normal conditions. PMID:23977198

  5. Examining the Gender Gap in Introductory Physics

    NASA Astrophysics Data System (ADS)

    Kost, Lauren; Pollock, Steven; Finkelstein, Noah

    2009-05-01

    Our previous research[1] showed that despite the use of interactive engagement techniques in the introductory physics course, the gap in performance between males and females on a mechanics conceptual learning survey persisted from pre- to post-test, at our institution. Such findings were counter to previously published work[2]. Follow-up studies[3] identified correlations between student performance on the conceptual learning survey and students' prior physics and math knowledge and their incoming attitudes and beliefs about physics and learning physics. The results indicate that the gender gap at our institution is predominantly associated with differences in males' and females' previous physics and math knowledge, and attitudes and beliefs. Our current work extends these results in two ways: 1) we look at the gender gap in the second semester of the introductory sequence and find results similar to those in the first semester course and 2) we identify ways in which males and females differentially experience several aspects of the introductory course. [1] Pollock, et al, Phys Rev: ST: PER 3, 010107. [2] Lorenzo, et al, Am J Phys 74, 118. [3] Kost, et al, PERC Proceedings 2008.

  6. Media multitasking and implicit learning.

    PubMed

    Edwards, Kathleen S; Shin, Myoungju

    2017-07-01

    Media multitasking refers to the simultaneous use of different forms of media. Previous research comparing heavy media multitaskers and light media multitaskers suggests that heavy media multitaskers have a broader scope of attention. The present study explored whether these differences in attentional scope would lead to a greater degree of implicit learning for heavy media multitaskers. The study also examined whether media multitasking behaviour is associated with differences in visual working memory, and whether visual working memory differentially affects the ability to process contextual information. In addition to comparing extreme groups (heavy and light media multitaskers) the study included analysis of people who media multitask in moderation (intermediate media multitaskers). Ninety-four participants were divided into groups based on responses to the media use questionnaire, and completed the contextual cueing and n-back tasks. Results indicated that the speed at which implicit learning occurred was slower in heavy media multitaskers relative to both light and intermediate media multitaskers. There was no relationship between working memory performance and media multitasking group, and no relationship between working memory and implicit learning. There was also no evidence for superior performance of intermediate media multitaskers. A deficit in implicit learning observed in heavy media multitaskers is consistent with previous literature, which suggests that heavy media multitaskers perform more poorly than light media multitaskers in attentional tasks due to their wider attentional scope.

  7. Functional capacity evaluation of work performance among individuals with pelvic injuries following motor vehicle accidents.

    PubMed

    Ratzon, Navah Z; Ari Shevil, Eynat Ben; Froom, Paul; Friedman, Sharon; Amit, Yehuda

    2013-01-01

    Pelvic injuries following motor vehicle accidents (MVA) cause disability and affect work capabilities. This study evaluated functional, self-report, and medical-based factors that could predict work capacity as was reflected in a functional capacity evaluation (FCE) among persons who sustained a pelvic injury. It was hypothesized that self-reported functional status and bio-demographic variables would predict work capacity. Sixty-one community-dwelling adults previously hospitalized following a MVA induced pelvic injury. FCE for work performance was conducted using the Physical Work Performance Evaluation (PWPE). Additional data was collected through a demographics questionnaire and the Functional Status Questionnaire. All participants underwent an orthopedic medical examination of the hip and lower extremities. Most participants self-reported that their work capacity post-injury were lower than their job required. PWPE scores indicated below-range functional performance. Regression models predicted 23% to 51% of PWPE subtests. Participants' self-report of functioning (instrumental activities of daily living and work) and bio-demographic variables (gender and age) were better predictors of PWPE scores than factors originating from the medical examination. Results support the inclusion of FCE, in addition to self-report of functioning and medical examination, to evaluate work capacity among individuals' post-pelvic injury and interventions and discharge planning.

  8. Spontaneous Speech Events in Two Speech Databases of Human-Computer and Human-Human Dialogs in Spanish

    ERIC Educational Resources Information Center

    Rodriguez, Luis J.; Torres, M. Ines

    2006-01-01

    Previous works in English have revealed that disfluencies follow regular patterns and that incorporating them into the language model of a speech recognizer leads to lower perplexities and sometimes to a better performance. Although work on disfluency modeling has been applied outside the English community (e.g., in Japanese), as far as we know…

  9. 30 CFR 48.27 - Training of miners assigned to a task in which they have had no previous experience; minimum...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... RETRAINING OF MINERS Training and Retraining of Miners Working at Surface Mines and Surface Areas of... shall not be required for miners who have been trained and who have demonstrated safe operating... required for miners who have performed the new work tasks and who have demonstrated safe operating...

  10. Determination of Global Stability of the Slosh Motion in a Spacecraft via Num Erical Experiment

    NASA Astrophysics Data System (ADS)

    Kang, Ja-Young

    2003-12-01

    The global stability of the attitude motion of a spin-stabilized space vehicle is investigated by performing numerical experiment. In the previous study, a stationary solution and a particular resonant condition for a given model were found by using analytical method but failed to represent the system stability over parameter values near and off the stationary points. Accordingly, as an extension of the previous work, this study performs numerical experiment to investigate the stability of the system across the parameter space and determines stable and unstable regions of the design parameters of the system.

  11. Shock compression response of cold-rolled Ni/Al multilayer composites

    NASA Astrophysics Data System (ADS)

    Specht, Paul E.; Weihs, Timothy P.; Thadhani, Naresh N.

    2017-01-01

    Uniaxial strain, plate-on-plate impact experiments were performed on cold-rolled Ni/Al multilayer composites and the resulting Hugoniot was determined through time-resolved measurements combined with impedance matching. The experimental Hugoniot agreed with that previously predicted by two dimensional (2D) meso-scale calculations [Specht et al., J. Appl. Phys. 111, 073527 (2012)]. Additional 2D meso-scale simulations were performed using the same computational method as the prior study to reproduce the experimentally measured free surface velocities and stress profiles. These simulations accurately replicated the experimental profiles, providing additional validation for the previous computational work.

  12. Methodological considerations for documenting the energy demand of dance activity: a review

    PubMed Central

    Beck, Sarah; Redding, Emma; Wyon, Matthew A.

    2015-01-01

    Previous research has explored the intensity of dance class, rehearsal, and performance and attempted to document the body's physiological adaptation to these activities. Dance activity is frequently described as: complex, diverse, non-steady state, intermittent, of moderate to high intensity, and with notable differences between training and performance intensities and durations. Many limitations are noted in the methodologies of previous studies creating barriers to consensual conclusion. The present study therefore aims to examine the previous body of literature and in doing so, seeks to highlight important methodological considerations for future research in this area to strengthen our knowledge base. Four recommendations are made for future research. Firstly, research should continue to be dance genre specific, with detailed accounts of technical and stylistic elements of the movement vocabulary examined given wherever possible. Secondly, a greater breadth of performance repertoire, within and between genres, needs to be closely examined. Thirdly, a greater focus on threshold measurements is recommended due to the documented complex interplay between aerobic and anaerobic energy systems. Lastly, it is important for research to begin to combine temporal data relating to work and rest periods with real-time measurement of metabolic data in work and rest, in order to be able to quantify demand more accurately. PMID:25999885

  13. Gait performance is not influenced by working memory when walking at a self-selected pace.

    PubMed

    Grubaugh, Jordan; Rhea, Christopher K

    2014-02-01

    Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

  14. Laboratory and field based evaluation of chromatography related performance of the Monitor for Aerosols and Gases in Ambient Air (MARGA)

    EPA Science Inventory

    The Monitor for AeRosols and GAses in ambient air (MARGA) is an on-line ion-chromatography-based instrument designed for speciation of the inorganic gas and aerosol ammonium-nitrate-sulfate system. Previous work to characterize the performance of the MARGA has been primarily base...

  15. Changing Stereotypes, Changing Grades: A Longitudinal Study of Stereotyping during a College Math Course

    ERIC Educational Resources Information Center

    Ramsey, Laura R.; Sekaquaptewa, Denise

    2011-01-01

    Previous research has illuminated an important connection between stereotypes and the performance of those targeted by a stereotype. This body of work suggests that even implicit (i.e., nonconscious and unintended) math-gender stereotyping is related to poor math performance among women. Our longitudinal study sought to measure students'…

  16. The More, the Better? The Impact of Instructional Time on Student Performance

    ERIC Educational Resources Information Center

    Cattaneo, Maria A.; Oggenfuss, Chantal; Wolter, Stefan C.

    2017-01-01

    Building on earlier work that explored within-student variation in hours of instruction across school subjects, we investigate the impact of instruction time on student test scores in Switzerland, as measured by the PISA 2009 test. Our results confirm the results of previous studies of a positive effect of instruction time on student performance.…

  17. ACUTE AND REPEATED INHALATION OF TOLUENE BY RATS PERFORMING A SIGNAL DETECTION TASK LEADS TO BEHAVIORAL TOLERANCE ON SOME PERFORMANCE MEASURES.

    EPA Science Inventory

    Previous work showed that trichloroethylene (TCE) impairs accuracy and latency in a signal detection task (SDT) in rats, and that these effects abate during repeated exposures if rats inhale TCE during SDT testing. The present experiment compared the effects of acute and repeated...

  18. Shared processing in multiple object tracking and visual working memory in the absence of response order and task order confounds

    PubMed Central

    Howe, Piers D. L.

    2017-01-01

    To understand how the visual system represents multiple moving objects and how those representations contribute to tracking, it is essential that we understand how the processes of attention and working memory interact. In the work described here we present an investigation of that interaction via a series of tracking and working memory dual-task experiments. Previously, it has been argued that tracking is resistant to disruption by a concurrent working memory task and that any apparent disruption is in fact due to observers making a response to the working memory task, rather than due to competition for shared resources. Contrary to this, in our experiments we find that when task order and response order confounds are avoided, all participants show a similar decrease in both tracking and working memory performance. However, if task and response order confounds are not adequately controlled for we find substantial individual differences, which could explain the previous conflicting reports on this topic. Our results provide clear evidence that tracking and working memory tasks share processing resources. PMID:28410383

  19. Shared processing in multiple object tracking and visual working memory in the absence of response order and task order confounds.

    PubMed

    Lapierre, Mark D; Cropper, Simon J; Howe, Piers D L

    2017-01-01

    To understand how the visual system represents multiple moving objects and how those representations contribute to tracking, it is essential that we understand how the processes of attention and working memory interact. In the work described here we present an investigation of that interaction via a series of tracking and working memory dual-task experiments. Previously, it has been argued that tracking is resistant to disruption by a concurrent working memory task and that any apparent disruption is in fact due to observers making a response to the working memory task, rather than due to competition for shared resources. Contrary to this, in our experiments we find that when task order and response order confounds are avoided, all participants show a similar decrease in both tracking and working memory performance. However, if task and response order confounds are not adequately controlled for we find substantial individual differences, which could explain the previous conflicting reports on this topic. Our results provide clear evidence that tracking and working memory tasks share processing resources.

  20. Measuring the performance of transit relative to livability.

    DOT National Transportation Integrated Search

    2013-03-01

    This project sought to understand the relationship between urban form, transit service characteristics, and ridership measured at the stop level. Most previous work in this area has looked at these issues separately, by either linking system performa...

  1. Numerical comparison of grid pattern diffraction effects through measurement and modeling with OptiScan software

    NASA Astrophysics Data System (ADS)

    Murray, Ian B.; Densmore, Victor; Bora, Vaibhav; Pieratt, Matthew W.; Hibbard, Douglas L.; Milster, Tom D.

    2011-06-01

    Coatings of various metalized patterns are used for heating and electromagnetic interference (EMI) shielding applications. Previous work has focused on macro differences between different types of grids, and has shown good correlation between measurements and analyses of grid diffraction. To advance this work, we have utilized the University of Arizona's OptiScan software, which has been optimized for this application by using the Babinet Principle. When operating on an appropriate computer system, this algorithm produces results hundreds of times faster than standard Fourier-based methods, and allows realistic cases to be modeled for the first time. By using previously published derivations by Exotic Electro-Optics, we compare diffraction performance of repeating and randomized grid patterns with equivalent sheet resistance using numerical performance metrics. Grid patterns of each type are printed on optical substrates and measured energy is compared against modeled energy.

  2. SASS Applied to Optimum Work Roll Profile Selection in the Hot Rolling of Wide Steel

    NASA Astrophysics Data System (ADS)

    Nolle, Lars

    The quality of steel strip produced in a wide strip rolling mill depends heavily on the careful selection of initial ground work roll profiles for each of the mill stands in the finishing train. In the past, these profiles were determined by human experts, based on their knowledge and experience. In previous work, the profiles were successfully optimised using a self-organising migration algorithm (SOMA). In this research, SASS, a novel heuristic optimisation algorithm that has only one control parameter, has been used to find the optimum profiles for a simulated rolling mill. The resulting strip quality produced using the profiles found by SASS is compared with results from previous work and the quality produced using the original profile specifications. The best set of profiles found by SASS clearly outperformed the original set and performed equally well as SOMA without the need of finding a suitable set of control parameters.

  3. Do work technique and musculoskeletal symptoms differ between men and women performing the same type of work tasks?

    PubMed

    Dahlberg, Raymond; Karlqvist, Lena; Bildt, Carina; Nykvist, Karin

    2004-11-01

    Musculoskeletal disorders are more common among women than among men. When comparing the difference between men and women in the prevalence of musculoskeletal disorders, methodological problems arise as men and women seldom perform the same type of activities, neither at work nor at home. The main objective of this cross-sectional case study was to compare work technique and self-reported musculoskeletal symptoms between men and women performing the same type of work tasks within a metal industry. Other factors, such as leisure activities, were also taken into consideration. Three data collection methods were used; questionnaire, interviews and systematic observations. The results from the observations revealed that women worked more frequently and during longer times with their hands above shoulder height than men. Working with hands above shoulder height is considered a risk factor for neck and shoulder disorders according to previous studies. Workplace design factors were probably a reason for differences in working technique between men and women. A higher proportion of women than men reported shoulder symptoms. Women spent more time on household activities than men, which indicates a higher total workload in paid and unpaid work.

  4. Long working hours and sickness absence-a fixed effects design.

    PubMed

    Bernstrøm, Vilde Hoff

    2018-05-02

    While long working hours seem to lead to impaired health, several studies have also shown that long working hours are related to lower levels of sickness absence. Previous studies on the relationship between long working hours and sickness absence have compared those who work long hours to those who do not, looking only at between-individual correlations. Those results might therefore reflect relatively stable differences between employees who typically work long hours and employees who typically do not. The aim of the present study is to examine within-individual correlations between long working hours and sickness absence. Records from the Human Resources department in a large Norwegian hospital from 2012 to 2015 provided objective data on both working hours and sickness absence. Two analyses were performed: a prospective cohort analysis to replicate the results from previous between-individual analyses and a second analysis of within-individual correlations using a fixed effect design. In line with existing research, both between-individual and within-individual analyses showed a negative relationship between long working hours (> 48 h/week) and short-term sickness absence (1-8 days) and no significant difference in incidence of long-term sickness absence (> 8 days). The results indicate that the negative relationship between long working hours and sickness absence is not due only to relatively stable individual differences between those who typically work long hours and those who do not. The results from both analyses therefore still contrast with previous research showing a negative relationship between long working hours and other health indicators.

  5. Up-conversion of MMW radiation to visual band using glow discharge detector and silicon detector

    NASA Astrophysics Data System (ADS)

    Aharon Akram, Avihai; Rozban, Daniel; Abramovich, Amir; Yitzhaky, Yitzhak; Kopeika, Natan S.

    2016-10-01

    In this work we describe and demonstrate a method for up-conversion of millimeter wave (MMW) radiation to the visual band using a very inexpensive miniature Glow Discharge Detector (GDD), and a silicon detector (photodetector). Here we present 100 GHz up-conversion images based on measuring the visual light emitting from the GDD rather than its electrical current. The results showed better response time of 480 ns and better sensitivity compared to the electronic detection that was performed in our previous work. In this work we performed MMW imaging based on this method using a GDD lamp, and a photodetector to measure GDD light emission.

  6. A prediction model for early death in non-small cell lung cancer patients following curative-intent chemoradiotherapy.

    PubMed

    Jochems, Arthur; El-Naqa, Issam; Kessler, Marc; Mayo, Charles S; Jolly, Shruti; Matuszak, Martha; Faivre-Finn, Corinne; Price, Gareth; Holloway, Lois; Vinod, Shalini; Field, Matthew; Barakat, Mohamed Samir; Thwaites, David; de Ruysscher, Dirk; Dekker, Andre; Lambin, Philippe

    2018-02-01

    Early death after a treatment can be seen as a therapeutic failure. Accurate prediction of patients at risk for early mortality is crucial to avoid unnecessary harm and reducing costs. The goal of our work is two-fold: first, to evaluate the performance of a previously published model for early death in our cohorts. Second, to develop a prognostic model for early death prediction following radiotherapy. Patients with NSCLC treated with chemoradiotherapy or radiotherapy alone were included in this study. Four different cohorts from different countries were available for this work (N = 1540). The previous model used age, gender, performance status, tumor stage, income deprivation, no previous treatment given (yes/no) and body mass index to make predictions. A random forest model was developed by learning on the Maastro cohort (N = 698). The new model used performance status, age, gender, T and N stage, total tumor volume (cc), total tumor dose (Gy) and chemotherapy timing (none, sequential, concurrent) to make predictions. Death within 4 months of receiving the first radiotherapy fraction was used as the outcome. Early death rates ranged from 6 to 11% within the four cohorts. The previous model performed with AUC values ranging from 0.54 to 0.64 on the validation cohorts. Our newly developed model had improved AUC values ranging from 0.62 to 0.71 on the validation cohorts. Using advanced machine learning methods and informative variables, prognostic models for early mortality can be developed. Development of accurate prognostic tools for early mortality is important to inform patients about treatment options and optimize care.

  7. Creep of salt from the ERDA-9 borehole and the WIPP (Waste Isolation Pilot Plant) workings

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

    Senseny, P.E.

    1990-01-01

    Six triaxial compression creep tests were performed to measure the creep deformation of salt from the ERDA-9 borehole and salt from the underground workings at the Waste Isolation Pilot Plant (WIPP). Even though the test matrix is quite limited, important results were obtained that added to existing data from previous test matrices. The WIPP salt was annealed to reduce the hardening that occurred as the openings deformed after mining. Five tests were performed at a temperature of 25{degree}C, a confining pressure of 15 MPa, and stress differences of either 10.0 or 15.0 MPa. The sixth test was performed at amore » temperature of 22{degree}C, a confining pressure of 20.7 MPa, and a stress difference of 11.7 MPa. Test duration ranged from approximately 160 to 335 days. Deformation of these six specimens is compared with that obtained previously under identical test conditions for specimens from other horizons of the ERDA-9 borehole and from unannealed specimens from the WIPP workings. Results suggest that the magnitude of the transient deformation depends on the horizon from which the specimen was taken and whether or not the specimen hardened in situ as the mined openings deformed. 9 refs., 7 figs., 3 tabs.« less

  8. System-theoretic Interpretation of the Mode Sensing Hypothesis

    DTIC Science & Technology

    2014-08-01

    estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the...6. AUTHOR(S) Prof. Rafal Zbikowski Prof. Graham Taylor 5d. PROJECT NUMBER 5d. TASK NUMBER 5e. WORK UNIT NUMBER 7. PERFORMING...insect flight control has more recently been modelled. The approach that we adopt here differs from previous, related work in several fundamental

  9. Continued Development of Expert System Tools for NPSS Engine Diagnostics

    NASA Technical Reports Server (NTRS)

    Lewandowski, Henry

    1996-01-01

    The objectives of this grant were to work with previously developed NPSS (Numerical Propulsion System Simulation) tools and enhance their functionality; explore similar AI systems; and work with the High Performance Computing Communication (HPCC) K-12 program. Activities for this reporting period are briefly summarized and a paper addressing the implementation, monitoring and zooming in a distributed jet engine simulation is included as an attachment.

  10. Comparison of the efficiency of rat papillary muscles during afterloaded isotonic contractions and contractions with sinusoidal length changes.

    PubMed

    Mellors, L J; Gibbs, C L; Barclay, C J

    2001-05-01

    The results of previous studies suggest that the maximum mechanical efficiency of rat papillary muscles is lower during a contraction protocol involving sinusoidal length changes than during one involving afterloaded isotonic contractions. The aim of this study was to compare directly the efficiency of isolated rat papillary muscle preparations in isotonic and sinusoidal contraction protocols. Experiments were performed in vitro (27 degrees C) using left ventricular papillary muscles from adult rats. Each preparation performed three contraction protocols: (i) low-frequency afterloaded isotonic contractions (10 twitches at 0.2 Hz), (ii) sinusoidal length change contractions with phasic stimulation (40 twitches at 2 Hz) and (iii) high-frequency afterloaded isotonic contractions (40 twitches at 2 Hz). The first two protocols resembled those used in previous studies and the third combined the characteristics of the first two. The parameters for each protocol were adjusted to those that gave maximum efficiency. For the afterloaded isotonic protocols, the afterload was set to 0.3 of the maximum developed force. The sinusoidal length change protocol incorporated a cycle amplitude of +/-5% resting length and a stimulus phase of -10 degrees. Measurements of force output, muscle length change and muscle temperature change were used to calculate the work and heat produced during and after each protocol. Net mechanical efficiency was defined as the proportion of the energy (enthalpy) liberated by the muscle that appeared as work. The efficiency in the low-frequency, isotonic contraction protocol was 21.1+/-1.4% (mean +/- s.e.m., N=6) and that in the sinusoidal protocol was 13.2+/-0.7%, consistent with previous results. This difference was not due to the higher frequency or greater number of twitches because efficiency in the high-frequency, isotonic protocol was 21.5+/-1.0%. Although these results apparently confirm that efficiency is protocol-dependent, additional experiments designed to measure work output unambiguously indicated that the method used to calculate work output in isotonic contractions overestimated actual work output. When net work output, which excludes work done by parallel elastic elements, rather than total work output was used to determine efficiency in afterloaded isotonic contractions, efficiency was similar to that for sinusoidal contractions. The maximum net mechanical efficiency of rat papillary muscles performing afterloaded isotonic or sinusoidal length change contractions was between 10 and 15%.

  11. Working parameters affecting earth-air heat exchanger (EAHE) system performance for passive cooling: A review

    NASA Astrophysics Data System (ADS)

    Darius, D.; Misaran, M. S.; Rahman, Md. M.; Ismail, M. A.; Amaludin, A.

    2017-07-01

    The study on the effect of the working parameters such as pipe material, pipe length, pipe diameter, depth of burial of the pipe, air flow rate and different types of soils on the thermal performance of earth-air heat exchanger (EAHE) systems is very crucial to ensure that thermal comfort can be achieved. In the past decade, researchers have performed studies to develop numerical models for analysis of EAHE systems. Until recently, two-dimensional models replaced the numerical models in the 1990s and in recent times, more advanced analysis using three-dimensional models, specifically the Computational Fluid Dynamics (CFD) simulation in the analysis of EAHE system. This paper reviews previous models used to analyse the EAHE system and working parameters that affects the earth-air heat exchanger (EAHE) thermal performance as of February 2017. Recent findings on the parameters affecting EAHE performance are also presented and discussed. As a conclusion, with the advent of CFD methods, investigational work have geared up to modelling and simulation work as it saves time and cost. Comprehension of the EAHE working parameters and its effect on system performance is largely established. However, the study on type of soil and its characteristics on the performance of EAHEs systems are surprisingly barren. Therefore, future studies should focus on the effect of soil characteristics such as moisture content, density of soil, and type of soil on the thermal performance of EAHEs system.

  12. Does Extrinsic Goal Framing Enhance Extrinsic Goal-Oriented Individuals' Learning and Performance? An Experimental Test of the Match Perspective versus Self-Determination Theory

    ERIC Educational Resources Information Center

    Vansteenkiste, Maarten; Timmermans, Tinneke; Lens, Willy; Soenens, Bart; Van den Broeck, Anja

    2008-01-01

    Previous work within self-determination theory has shown that experimentally framing a learning activity in terms of extrinsic rather than intrinsic goals results in poorer conceptual learning and performance, presumably because extrinsic goal framing detracts attention from the learning activity and is less directly satisfying of basic…

  13. Using Words Instead of Jumbled Characters as Stimuli in Keyboard Training Facilitates Fluent Performance

    ERIC Educational Resources Information Center

    DeFulio, Anthony; Crone-Todd, Darlene E.; Long, Lauren V.; Nuzzo, Paul A.; Silverman, Kenneth

    2011-01-01

    Keyboarding skill is an important target for adult education programs due to the ubiquity of computers in modern work environments. A previous study showed that novice typists learned key locations quickly but that fluency took a relatively long time to develop. In the present study, novice typists achieved fluent performance in nearly half the…

  14. Massive Memory Revisited: Limitations on Storage Capacity for Object Details in Visual Long-Term Memory

    ERIC Educational Resources Information Center

    Cunningham, Corbin A.; Yassa, Michael A.; Egeth, Howard E.

    2015-01-01

    Previous work suggests that visual long-term memory (VLTM) is highly detailed and has a massive capacity. However, memory performance is subject to the effects of the type of testing procedure used. The current study examines detail memory performance by probing the same memories within the same subjects, but using divergent probing methods. The…

  15. Reducing dietary protein in pond production of hybrid striped bass (Morone chrysops x M. saxatilis): Effects on fish performance and water quality dynamics

    USDA-ARS?s Scientific Manuscript database

    In previous work, we demonstrated that diets containing 40% digestible protein (DP) (45% crude protein) and 18 %lipid supplemented with Met and Lys resulted in superior performance and nutrient retentions in hybrid striped bass compared to less energy-dense diets when rearing hybrid striped bass at ...

  16. Selective updating of working memory content modulates meso-cortico-striatal activity.

    PubMed

    Murty, Vishnu P; Sambataro, Fabio; Radulescu, Eugenia; Altamura, Mario; Iudicello, Jennifer; Zoltick, Bradley; Weinberger, Daniel R; Goldberg, Terry E; Mattay, Venkata S

    2011-08-01

    Accumulating evidence from non-human primates and computational modeling suggests that dopaminergic signals arising from the midbrain (substantia nigra/ventral tegmental area) mediate striatal gating of the prefrontal cortex during the selective updating of working memory. Using event-related functional magnetic resonance imaging, we explored the neural mechanisms underlying the selective updating of information stored in working memory. Participants were scanned during a novel working memory task that parses the neurophysiology underlying working memory maintenance, overwriting, and selective updating. Analyses revealed a functionally coupled network consisting of a midbrain region encompassing the substantia nigra/ventral tegmental area, caudate, and dorsolateral prefrontal cortex that was selectively engaged during working memory updating compared to the overwriting and maintenance of working memory content. Further analysis revealed differential midbrain-dorsolateral prefrontal interactions during selective updating between low-performing and high-performing individuals. These findings highlight the role of this meso-cortico-striatal circuitry during the selective updating of working memory in humans, which complements previous research in behavioral neuroscience and computational modeling. Published by Elsevier Inc.

  17. A Rigid Mid-Lift-to-Drag Ratio Approach to Human Mars Entry, Descent, and Landing

    NASA Technical Reports Server (NTRS)

    Cerimele, Christopher J.; Robertson, Edward A.; Sostaric, Ronald R.; Campbell, Charles H.; Robinson, Phil; Matz, Daniel A.; Johnson, Breanna J.; Stachowiak, Susan J.; Garcia, Joseph A.; Bowles, Jeffrey V.; hide

    2017-01-01

    Current NASA Human Mars architectures require delivery of approximately 20 metric tons of cargo to the surface in a single landing. A proposed vehicle type for performing the entry, descent, and landing at Mars associated with this architecture is a rigid, enclosed, elongated lifting body shape that provides a higher lift-to-drag ratio (L/D) than a typical entry capsule, but lower than a typical winged entry vehicle (such as the Space Shuttle Orbiter). A rigid Mid-L/D shape has advantages for large mass Mars EDL, including loads management, range capability during entry, and human spaceflight heritage. Previous large mass Mars studies have focused more on symmetric and/or circular cross-section Mid-L/D shapes such as the ellipsled. More recent work has shown performance advantages for non-circular cross section shapes. This paper will describe efforts to design a rigid Mid-L/D entry vehicle for Mars which shows mass and performance improvements over previous Mid-L/D studies. The proposed concept, work to date and evolution, forward path, and suggested future strategy are described.

  18. Node Immunization with Time-Sensitive Restrictions.

    PubMed

    Cui, Wen; Gong, Xiaoqing; Liu, Chen; Xu, Dan; Chen, Xiaojiang; Fang, Dingyi; Tang, Shaojie; Wu, Fan; Chen, Guihai

    2016-12-15

    When we encounter a malicious rumor or an infectious disease outbreak, immunizing k nodes of the relevant network with limited resources is always treated as an extremely effective method. The key challenge is how we can insulate limited nodes to minimize the propagation of those contagious things. In previous works, the best k immunised nodes are selected by learning the initial status of nodes and their strategies even if there is no feedback in the propagation process, which eventually leads to ineffective performance of their solutions. In this paper, we design a novel vaccines placement strategy for protecting much more healthy nodes from being infected by infectious nodes. The main idea of our solution is that we are not only utilizing the status of changing nodes as auxiliary knowledge to adjust our scheme, but also comparing the performance of vaccines in various transmission slots. Thus, our solution has a better chance to get more benefit from these limited vaccines. Extensive experiments have been conducted on several real-world data sets and the results have shown that our algorithm has a better performance than previous works.

  19. Node Immunization with Time-Sensitive Restrictions

    PubMed Central

    Cui, Wen; Gong, Xiaoqing; Liu, Chen; Xu, Dan; Chen, Xiaojiang; Fang, Dingyi; Tang, Shaojie; Wu, Fan; Chen, Guihai

    2016-01-01

    When we encounter a malicious rumor or an infectious disease outbreak, immunizing k nodes of the relevant network with limited resources is always treated as an extremely effective method. The key challenge is how we can insulate limited nodes to minimize the propagation of those contagious things. In previous works, the best k immunised nodes are selected by learning the initial status of nodes and their strategies even if there is no feedback in the propagation process, which eventually leads to ineffective performance of their solutions. In this paper, we design a novel vaccines placement strategy for protecting much more healthy nodes from being infected by infectious nodes. The main idea of our solution is that we are not only utilizing the status of changing nodes as auxiliary knowledge to adjust our scheme, but also comparing the performance of vaccines in various transmission slots. Thus, our solution has a better chance to get more benefit from these limited vaccines. Extensive experiments have been conducted on several real-world data sets and the results have shown that our algorithm has a better performance than previous works. PMID:27983680

  20. Beta-hydroxy-beta-methylbutyrate (HMB) ameliorates age-related deficits in water maze performance, especially in male rats.

    PubMed

    Kougias, Daniel G; Hankosky, Emily R; Gulley, Joshua M; Juraska, Janice M

    2017-03-01

    Beta-hydroxy-beta-methylbutyrate (HMB) is commonly supplemented to maintain muscle in elderly and clinical populations and has potential as a nootropic. Previously, we have shown that in both male and female rats, long-term HMB supplementation prevents age-related dendritic shrinkage within the medial prefrontal cortex (mPFC) and improves cognitive flexibility and working memory performance that are both age- and sex-specific. In this study, we further explore the cognitive effects by assessing visuospatial learning and memory with the Morris water maze. Female rats were ovariectomized at 11months of age to model human menopause. At 12months of age, male and female rats received relatively short- or long-term (1- or 7-month) dietary HMB (450mg/kg/dose) supplementation twice a day prior to testing. Spatial reference learning and memory was assessed across four days in the water maze with four trials daily and a probe trial on the last day. Consistent with previous work, there were age-related deficits in water maze performance in both sexes. However, these deficits were ameliorated in HMB-treated males during training and in both sexes during probe trial performance. Thus, HMB supplementation prevented the age-related decrement in water maze performance, especially in male rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Maintaining the Fighting Force: Cohesion and Support Systems

    DTIC Science & Technology

    1985-10-01

    underrepresented numbers (Kanter, 1977), external pressure to include a previously excluded group, and marginality resulting from minimal adaptation by the...Lots of individual performances yet some teamwork items - all working toward the final result. NEGATIVE Rugby Scrum - Massive confusion. Soccer

  2. Performance Efficiency of a Crash Energy Management System

    DOT National Transportation Integrated Search

    2007-03-13

    Previous work has led to the development of a crash energy : management (CEM) system designed to distribute crush : throughout unoccupied areas of a passenger train in a collision : event. This CEM system is comprised of crush zones at the : front an...

  3. Workaholism vs. work engagement: the two different predictors of future well-being and performance.

    PubMed

    Shimazu, Akihito; Schaufeli, Wilmar B; Kamiyama, Kimika; Kawakami, Norito

    2015-02-01

    This study investigated the distinctiveness of two types of heavy work investment (i.e., workaholism and work engagement) by examining their 2-year longitudinal relationships with employee well-being and job performance. Based on a previous cross-sectional study by Shimazu and Schaufeli (Ind Health 47:495-502, 2009) and a shorter term longitudinal study by Shimazu et al. (Ind Health 50:316-21, 2012; measurement interval = 7 months), we predicted that workaholism predicts long-term future unwell-being (i.e., high ill-health and low life satisfaction) and poor job performance, whereas work engagement predicts future well-being (i.e., low ill-health and high life satisfaction) and superior job performance. A two-wave survey was conducted among employees from one Japanese company, and valid data from 1,196 employees was analyzed using structural equation modeling. T1-T2 changes in ill-health, life satisfaction, and job performance were measured as residual scores, which were included in the structural equation model. Workaholism and work engagement were weakly and positively related to each other. In addition, and as expected, workaholism was related to an increase in ill-health and to a decrease in life satisfaction. In contrast, and also as expected, work engagement was related to increases in both life satisfaction and job performance and to a decrease in ill-health. Although workaholism and work engagement are weakly positively related, they constitute two different concepts. More specifically, workaholism has negative consequences across an extended period of 2 years, whereas work engagement has positive consequences in terms of well-being and performance. Hence, workaholism should be prevented and work engagement should be stimulated.

  4. Effects of major depression on moment-in-time work performance.

    PubMed

    Wang, Philip S; Beck, Arne L; Berglund, Pat; McKenas, David K; Pronk, Nicolaas P; Simon, Gregory E; Kessler, Ronald C

    2004-10-01

    Although major depression is thought to have substantial negative effects on work performance, the possibility of recall bias limits self-report studies of these effects. The authors used the experience sampling method to address this problem by collecting comparative data on moment-in-time work performance among service workers who were depressed and those who were not depressed. The group studied included 105 airline reservation agents and 181 telephone customer service representatives selected from a larger baseline sample; depressed workers were deliberately oversampled. Respondents were given pagers and experience sampling method diaries for each day of the study. A computerized autodialer paged respondents at random time points. When paged, respondents reported on their work performance in the diary. Moment-in-time work performance was assessed at five random times each day over a 7-day data collection period (35 data points for each respondent). Seven conditions (allergies, arthritis, back pain, headaches, high blood pressure, asthma, and major depression) occurred often enough in this group of respondents to be studied. Major depression was the only condition significantly related to decrements in both of the dimensions of work performance assessed in the diaries: task focus and productivity. These effects were equivalent to approximately 2.3 days absent because of sickness per depressed worker per month of being depressed. Previous studies based on days missed from work significantly underestimate the adverse economic effects associated with depression. Productivity losses related to depression appear to exceed the costs of effective treatment.

  5. Separation control with fluidic oscillators in water

    NASA Astrophysics Data System (ADS)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2017-08-01

    The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

  6. Longitudinal attentional engagement rescues mice from age-related cognitive declines and cognitive inflexibility

    PubMed Central

    Matzel, Louis D.; Light, Kenneth R.; Wass, Christopher; Colas-Zelin, Danielle; Denman-Brice, Alexander; Waddel, Adam C.; Kolata, Stefan

    2011-01-01

    Learning, attentional, and perseverative deficits are characteristic of cognitive aging. In this study, genetically diverse CD-1 mice underwent longitudinal training in a task asserted to tax working memory capacity and its dependence on selective attention. Beginning at 3 mo of age, animals were trained for 12 d to perform in a dual radial-arm maze task that required the mice to remember and operate on two sets of overlapping guidance (spatial) cues. As previously reported, this training resulted in an immediate (at 4 mo of age) improvement in the animals' aggregate performance across a battery of five learning tasks. Subsequently, these animals received an additional 3 d of working memory training at 3-wk intervals for 15 mo (totaling 66 training sessions), and at 18 mo of age were assessed on a selective attention task, a second set of learning tasks, and variations of those tasks that required the animals to modify the previously learned response. Both attentional and learning abilities (on passive avoidance, active avoidance, and reinforced alternation tasks) were impaired in aged animals that had not received working memory training. Likewise, these aged animals exhibited consistent deficits when required to modify a previously instantiated learned response (in reinforced alternation, active avoidance, and spatial water maze). In contrast, these attentional, learning, and perseverative deficits were attenuated in aged animals that had undergone lifelong working memory exercise. These results suggest that general impairments of learning, attention, and cognitive flexibility may be mitigated by a cognitive exercise regimen that requires chronic attentional engagement. PMID:21521768

  7. Longitudinal attentional engagement rescues mice from age-related cognitive declines and cognitive inflexibility.

    PubMed

    Matzel, Louis D; Light, Kenneth R; Wass, Christopher; Colas-Zelin, Danielle; Denman-Brice, Alexander; Waddel, Adam C; Kolata, Stefan

    2011-01-01

    Learning, attentional, and perseverative deficits are characteristic of cognitive aging. In this study, genetically diverse CD-1 mice underwent longitudinal training in a task asserted to tax working memory capacity and its dependence on selective attention. Beginning at 3 mo of age, animals were trained for 12 d to perform in a dual radial-arm maze task that required the mice to remember and operate on two sets of overlapping guidance (spatial) cues. As previously reported, this training resulted in an immediate (at 4 mo of age) improvement in the animals' aggregate performance across a battery of five learning tasks. Subsequently, these animals received an additional 3 d of working memory training at 3-wk intervals for 15 mo (totaling 66 training sessions), and at 18 mo of age were assessed on a selective attention task, a second set of learning tasks, and variations of those tasks that required the animals to modify the previously learned response. Both attentional and learning abilities (on passive avoidance, active avoidance, and reinforced alternation tasks) were impaired in aged animals that had not received working memory training. Likewise, these aged animals exhibited consistent deficits when required to modify a previously instantiated learned response (in reinforced alternation, active avoidance, and spatial water maze). In contrast, these attentional, learning, and perseverative deficits were attenuated in aged animals that had undergone lifelong working memory exercise. These results suggest that general impairments of learning, attention, and cognitive flexibility may be mitigated by a cognitive exercise regimen that requires chronic attentional engagement.

  8. The Persistence of the Gender Gap in Introductory Physics

    NASA Astrophysics Data System (ADS)

    Kost, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

    2008-10-01

    We previously showed[l] that despite teaching with interactive engagement techniques, the gap in performance between males and females on conceptual learning surveys persisted from pre- to posttest, at our institution. Such findings were counter to previously published work[2]. Our current work analyzes factors that may influence the observed gender gap in our courses. Posttest conceptual assessment data are modeled using both multiple regression and logistic regression analyses to estimate the gender gap in posttest scores after controlling for background factors that vary by gender. We find that at our institution the gender gap persists in interactive physics classes, but is largely due to differences in physics and math preparation and incoming attitudes and beliefs.

  9. Symptoms of musculoskeletal disorders among ammunition factory workers in Turkey.

    PubMed

    Pinar, Tevfik; Cakmak, Z Aytul; Saygun, Meral; Akdur, Recep; Ulu, Nuriye; Keles, Isik; Saylam, Hamdi Saim

    2013-01-01

    The aim of this study was to assess the prevalence of symptoms of work-related musculoskeletal disorders (MSDs) and to determine the risk factors among ammunition factory workers in Turkey. This cross-sectional study was performed on 955 ammunition factory workers. Potential risk factors were investigated with a questionnaire and multivariate logistic regression analysis was performed. During the previous year, 39.3% of ammunition workers experienced symptoms of work-related MSDs. Logistic regression analysis showed smoking (odds ratio [OR] = 1.372), chronic diseases (OR = 1.795), body mass index (BMI; overweight) (OR = 1.631), working year (OR = 1.509), cold temperature (OR = 1.838), and work load (OR = 2.210) were significant independent risk factors for the development of symptoms of MSDs. It was found that both work-related conditions and personal and environmental factors are important for the development of occupational MSDs.

  10. Working Memory and Cognitive Flexibility Mediates Visuoconstructional Abilities in Older Adults with Heterogeneous Cognitive Ability.

    PubMed

    Ávila, Rafaela T; de Paula, Jonas J; Bicalho, Maria A; Moraes, Edgar N; Nicolato, Rodrigo; Malloy-Diniz, Leandro F; Diniz, Breno S

    2015-05-01

    Previous studies suggest that executive functions influence the performance on visuoconstructional tasks. This study aims to investigate whether the relationship between planning ability and the copy of complex figures is mediated by distinct components of executive functions (i.e., working memory, inhibitory control and cognitive flexibility). We included a 129 older adults with Alzheimer's disease (n=36, AD), mild cognitive impairment (MCI, n=67), and with no evidence of cognitive impairment (controls, n=26). We evaluated the mediation effect of planning abilities, working memory, cognitive flexibility and inhibitory control on visuoconstructional tasks using a multiple mediation models. We found a significant direct effect of planning on visuoconstructional abilities and a partial mediation effect of working memory and cognitive flexibility on visuoconstructional abilities. The present results indicate that the performance on visuoconstructional task is mediated by multiple interrelated executive functions components, in particular working memory and cognitive flexibility.

  11. A facilitative effect of negative affective valence on working memory.

    PubMed

    Gotoh, Fumiko; Kikuchi, Tadashi; Olofsson, Ulrich

    2010-06-01

    Previous studies have shown that negatively valenced information impaired working memory performance due to an attention-capturing effect. The present study examined whether negative valence could also facilitate working memory. Affective words (negative, neutral, positive) were used as retro-cues in a working memory task that required participants to remember colors at different spatial locations on a computer screen. Following the cue, a target detection task was used to either shift attention to a different location or keep attention at the same location as the retro-cue. Finally, participants were required to discriminate the cued color from a set of distractors. It was found that negative cues yielded shorter response times (RTs) in the attention-shift condition and longer RTs in the attention-stay condition, compared with neutral and positive cues. The results suggest that negative affective valence may enhance working memory performance (RTs), provided that attention can be disengaged.

  12. Contribution of auditory working memory to speech understanding in mandarin-speaking cochlear implant users.

    PubMed

    Tao, Duoduo; Deng, Rui; Jiang, Ye; Galvin, John J; Fu, Qian-Jie; Chen, Bing

    2014-01-01

    To investigate how auditory working memory relates to speech perception performance by Mandarin-speaking cochlear implant (CI) users. Auditory working memory and speech perception was measured in Mandarin-speaking CI and normal-hearing (NH) participants. Working memory capacity was measured using forward digit span and backward digit span; working memory efficiency was measured using articulation rate. Speech perception was assessed with: (a) word-in-sentence recognition in quiet, (b) word-in-sentence recognition in speech-shaped steady noise at +5 dB signal-to-noise ratio, (c) Chinese disyllable recognition in quiet, (d) Chinese lexical tone recognition in quiet. Self-reported school rank was also collected regarding performance in schoolwork. There was large inter-subject variability in auditory working memory and speech performance for CI participants. Working memory and speech performance were significantly poorer for CI than for NH participants. All three working memory measures were strongly correlated with each other for both CI and NH participants. Partial correlation analyses were performed on the CI data while controlling for demographic variables. Working memory efficiency was significantly correlated only with sentence recognition in quiet when working memory capacity was partialled out. Working memory capacity was correlated with disyllable recognition and school rank when efficiency was partialled out. There was no correlation between working memory and lexical tone recognition in the present CI participants. Mandarin-speaking CI users experience significant deficits in auditory working memory and speech performance compared with NH listeners. The present data suggest that auditory working memory may contribute to CI users' difficulties in speech understanding. The present pattern of results with Mandarin-speaking CI users is consistent with previous auditory working memory studies with English-speaking CI users, suggesting that the lexical importance of voice pitch cues (albeit poorly coded by the CI) did not influence the relationship between working memory and speech perception.

  13. Uplink transmit beamforming design for SINR maximization with full multiuser channel state information

    NASA Astrophysics Data System (ADS)

    Xi, Songnan; Zoltowski, Michael D.

    2008-04-01

    Multiuser multiple-input multiple-output (MIMO) systems are considered in this paper. We continue our research on uplink transmit beamforming design for multiple users under the assumption that the full multiuser channel state information, which is the collection of the channel state information between each of the users and the base station, is known not only to the receiver but also to all the transmitters. We propose an algorithm for designing optimal beamforming weights in terms of maximizing the signal-to-interference-plus-noise ratio (SINR). Through statistical modeling, we decouple the original mathematically intractable optimization problem and achieved a closed-form solution. As in our previous work, the minimum mean-squared error (MMSE) receiver with successive interference cancellation (SIC) is adopted for multiuser detection. The proposed scheme is compared with an existing jointly optimized transceiver design, referred to as the joint transceiver in this paper, and our previously proposed eigen-beamforming algorithm. Simulation results demonstrate that our algorithm, with much less computational burden, accomplishes almost the same performance as the joint transceiver for spatially independent MIMO channel and even better performance for spatially correlated MIMO channels. And it always works better than our previously proposed eigen beamforming algorithm.

  14. Models of performance of evolutionary program induction algorithms based on indicators of problem difficulty.

    PubMed

    Graff, Mario; Poli, Riccardo; Flores, Juan J

    2013-01-01

    Modeling the behavior of algorithms is the realm of evolutionary algorithm theory. From a practitioner's point of view, theory must provide some guidelines regarding which algorithm/parameters to use in order to solve a particular problem. Unfortunately, most theoretical models of evolutionary algorithms are difficult to apply to realistic situations. However, in recent work (Graff and Poli, 2008, 2010), where we developed a method to practically estimate the performance of evolutionary program-induction algorithms (EPAs), we started addressing this issue. The method was quite general; however, it suffered from some limitations: it required the identification of a set of reference problems, it required hand picking a distance measure in each particular domain, and the resulting models were opaque, typically being linear combinations of 100 features or more. In this paper, we propose a significant improvement of this technique that overcomes the three limitations of our previous method. We achieve this through the use of a novel set of features for assessing problem difficulty for EPAs which are very general, essentially based on the notion of finite difference. To show the capabilities or our technique and to compare it with our previous performance models, we create models for the same two important classes of problems-symbolic regression on rational functions and Boolean function induction-used in our previous work. We model a variety of EPAs. The comparison showed that for the majority of the algorithms and problem classes, the new method produced much simpler and more accurate models than before. To further illustrate the practicality of the technique and its generality (beyond EPAs), we have also used it to predict the performance of both autoregressive models and EPAs on the problem of wind speed forecasting, obtaining simpler and more accurate models that outperform in all cases our previous performance models.

  15. Visualization of N-body Simulations in Virtual Worlds

    NASA Astrophysics Data System (ADS)

    Knop, Robert A.; Ames, J.; Djorgovski, G.; Farr, W.; Hut, P.; Johnson, A.; McMillan, S.; Nakasone, A.; Vesperini, E.

    2010-01-01

    We report on work to use virtual worlds for visualizing the results of N-body calculations, on three levels. First, we have written a demonstration 3-body solver entirely in the scripting language of the popularly used virtual world Second Life. Second, we have written a physics module for the open source virtual world OpenSim that performs N-body calculations as the physics engine for the server, allowing natural 3-d visualization of the solution as the solution is being performed. Finally, we give an initial report on the potential use of virtual worlds to visualize calculations which have previously been performed, or which are being performed in other processes and reported to the virtual world server. This work has been performed as part of the Meta-Institute of Computational Astrophysics (MICA). http://www.mica-vw.org

  16. Gaming is related to enhanced working memory performance and task-related cortical activity.

    PubMed

    Moisala, M; Salmela, V; Hietajärvi, L; Carlson, S; Vuontela, V; Lonka, K; Hakkarainen, K; Salmela-Aro, K; Alho, K

    2017-01-15

    Gaming experience has been suggested to lead to performance enhancements in a wide variety of working memory tasks. Previous studies have, however, mostly focused on adult expert gamers and have not included measurements of both behavioral performance and brain activity. In the current study, 167 adolescents and young adults (aged 13-24 years) with different amounts of gaming experience performed an n-back working memory task with vowels, with the sensory modality of the vowel stream switching between audition and vision at random intervals. We studied the relationship between self-reported daily gaming activity, working memory (n-back) task performance and related brain activity measured using functional magnetic resonance imaging (fMRI). The results revealed that the extent of daily gaming activity was related to enhancements in both performance accuracy and speed during the most demanding (2-back) level of the working memory task. This improved working memory performance was accompanied by enhanced recruitment of a fronto-parietal cortical network, especially the dorsolateral prefrontal cortex. In contrast, during the less demanding (1-back) level of the task, gaming was associated with decreased activity in the same cortical regions. Our results suggest that a greater degree of daily gaming experience is associated with better working memory functioning and task difficulty-dependent modulation in fronto-parietal brain activity already in adolescence and even when non-expert gamers are studied. The direction of causality within this association cannot be inferred with certainty due to the correlational nature of the current study. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Eating Together at the Firehouse: How Workplace Commensality Relates to the Performance of Firefighters

    PubMed Central

    Kniffin, Kevin M.; Wansink, Brian; Devine, Carol M.; Sobal, Jeffery

    2015-01-01

    Cooperative activities among coworkers can provide valuable group-level benefits; however, previous research has often focused on artificial activities that require extraordinary efforts away from the worksite. We investigate organizational benefits that firms might obtain through various supports for coworkers to engage in commensality (i.e., eating together). We conducted field research within firehouses in a large city to explore the role that interacting over food might have for work-group performance. Using a mix of qualitative and quantitative methods, our field research shows a significant positive association between commensality and work-group performance. Our findings establish a basis for research and practice that focuses on ways that firms can enhance team performance by leveraging the mundane and powerful activity of eating. PMID:27226698

  18. Creativity and working memory capacity in sports: working memory capacity is not a limiting factor in creative decision making amongst skilled performers.

    PubMed

    Furley, Philip; Memmert, Daniel

    2015-01-01

    The goal of the study was to investigate the relationship between domain-general working memory capacity and domain-specific creativity amongst experienced soccer players. We administered the automated operation span task in combination with a domain-specific soccer creativity task to a group of 61 experienced soccer players to address the question whether an athlete's domain-specific creativity is restricted by their domain-general cognitive abilities (i.e., working memory capacity). Given that previous studies have either found a positive correlation, a negative correlation, or no correlation between working memory capacity and creativity, we analyzed the data in an exploratory manner by following recent recommendations to report effect-size estimations and their precision in form of 95% confidence intervals. The pattern of results provided evidence that domain-general working memory capacity is not associated with creativity in a soccer-specific creativity task. This pattern of results suggests that future research and theorizing on the role of working memory in everyday creative performance needs to distinguish between different types of creative performance while also taking the role of domain-specific experience into account.

  19. Creativity and working memory capacity in sports: working memory capacity is not a limiting factor in creative decision making amongst skilled performers

    PubMed Central

    Furley, Philip; Memmert, Daniel

    2015-01-01

    The goal of the study was to investigate the relationship between domain-general working memory capacity and domain-specific creativity amongst experienced soccer players. We administered the automated operation span task in combination with a domain-specific soccer creativity task to a group of 61 experienced soccer players to address the question whether an athlete’s domain-specific creativity is restricted by their domain-general cognitive abilities (i.e., working memory capacity). Given that previous studies have either found a positive correlation, a negative correlation, or no correlation between working memory capacity and creativity, we analyzed the data in an exploratory manner by following recent recommendations to report effect-size estimations and their precision in form of 95% confidence intervals. The pattern of results provided evidence that domain-general working memory capacity is not associated with creativity in a soccer-specific creativity task. This pattern of results suggests that future research and theorizing on the role of working memory in everyday creative performance needs to distinguish between different types of creative performance while also taking the role of domain-specific experience into account. PMID:25713552

  20. Altered Error-Related Activity in Patients with Schizophrenia

    ERIC Educational Resources Information Center

    Koch, Kathrin; Wagner, Gerd; Schultz, Christoph; Schachtzabel, Claudia; Nenadic, Igor; Axer, Martina; Reichenbach, Jurgen R.; Sauer, Heinrich; Schlosser, Ralf G. M.

    2009-01-01

    Deficits in working memory (WM) and executive cognitive control are core features of schizophrenia. However, findings regarding functional activation strengths are heterogeneous, partly due to differences in task demands and behavioral performance. Previous investigators proposed integrating these heterogeneous findings into a comprehensive model…

  1. A New Method of Administering the Grooved Pegboard Test: Performance as a Function of Handedness and Sex

    ERIC Educational Resources Information Center

    Bryden, P.J.; Roy, E.A.

    2005-01-01

    The purpose of the present study was twofold: first to examine the influences of sex and handedness on manual performance on the Grooved Pegboard Test; and secondly to provide normative data for two versions (Place and Remove tasks) of the Grooved Pegboard Test, as previous work (Bryden & Roy, 1999) had suggested that the Remove task of the…

  2. The Influence of Relationship Networks on Academic Performance in Higher Education: A Comparative Study between Students of a Creative and a Non-Creative Discipline

    ERIC Educational Resources Information Center

    Tomás-Miquel, José-Vicente; Expósito-Langa, Manuel; Nicolau-Juliá, Débora

    2016-01-01

    In recent years, the literature has highlighted the importance of relational aspects on student attainment in higher education. Much of this previous work agrees with the idea that students' connectedness has beneficial effects on their performance. However, this literature has generally overlooked the influence that the discipline of study may…

  3. Expanded Awareness of Student Performance: A Case Study in Applied Ethnographic Monitoring in a Bilingual Classroom. Sociolinguistic Working Paper Number 60.

    ERIC Educational Resources Information Center

    Carrasco, Robert L.

    The case study of the use of a classroom observation technique to evaluate the abilities and performance of a bilingual kindergarten student previously assessed as a low achiever is described. There are three objectives: to show the validity of the ethnographic monitoring technique, to show the value of teachers as collaborating researchers, and…

  4. Reaction time, inhibition, working memory and ‘delay aversion’ performance: genetic influences and their interpretation

    PubMed Central

    KUNTSI, JONNA; ROGERS, HANNAH; SWINARD, GREER; BÖRGER, NORBERT; van der MEERE, JAAP; RIJSDIJK, FRUHLING; ASHERSON, PHILIP

    2013-01-01

    Background For candidate endophenotypes to be useful for psychiatric genetic research, they first of all need to show significant genetic influences. To address the relative lack of previous data, we set to investigate the extent of genetic and environmental influences on performance in a set of theoretically driven cognitive-experimental tasks in a large twin sample. We further aimed to illustrate how test–retest reliability of the measures affects the estimates. Method Four-hundred 7- to 9-year-old twin pairs were assessed individually on tasks measuring reaction time, inhibition, working memory and ‘delay aversion’ performance. Test–retest reliability data on some of the key measures were available from a previous study. Results Several key measures of reaction time, inhibition and working-memory performance indicated a moderate degree of genetic influence. Combining data across theoretically related tasks increased the heritability estimates, as illustrated by the heritability estimates of 60% for mean reaction time and 50% for reaction-time variability. Psychometric properties (reliability or ceiling effects) had a substantial influence on the estimates for some measures. Conclusions The data support the usefulness of several of the variables for endophenotype studies that aim to link genes to cognitive and motivational processes. Importantly, the data also illustrate specific conditions under which the true extent of genetic influences may be underestimated and hence the usefulness for genetic mapping studies compromised, and suggest ways to address this. PMID:16882357

  5. Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment.

    PubMed

    Guild, Emma B; Vasquez, Brandon P; Maione, Andrea M; Mah, Linda; Ween, Jon; Anderson, Nicole D

    2014-01-01

    Previous studies have observed poorer working memory performance in individuals with amnestic mild cognitive impairment than in healthy older adults. It is unclear, however, whether these difficulties are true only of the multiple-domain clinical subtype in whom poorer executive functioning is common. The current study examined working memory, as measured by the self-ordered pointing task (SOPT) and an n-back task, in healthy older adults and adults with single-domain amnestic mild cognitive impairment (aMCI). Individuals with single-domain aMCI committed more errors and required longer to develop an organizational strategy on the SOPT. The single-domain aMCI group did not differ from healthy older adults on the 1-back or 2-back, but had poorer discrimination on the 3-back task. This is, to our knowledge, the first characterization of dynamic working memory performance in a single-domain aMCI group. These results lend support for the idea that clinical amnestic MCI subtypes may reflect different stages on a continuum of progression to dementia and question whether standardized measures of working memory (span tasks) are sensitive enough to capture subtle changes in performance.

  6. Recruitment of intuitive versus analytic thinking strategies affects the role of working memory in a gambling task.

    PubMed

    Gozzi, Marta; Cherubini, Paolo; Papagno, Costanza; Bricolo, Emanuela

    2011-05-01

    Previous studies found mixed results concerning the role of working memory (WM) in the gambling task (GT). Here, we aimed at reconciling inconsistencies by showing that the standard version of the task can be solved using intuitive strategies operating automatically, while more complex versions require analytic strategies drawing on executive functions. In Study 1, where good performance on the GT could be achieved using intuitive strategies, participants performed well both with and without a concurrent WM load. In Study 2, where analytical strategies were required to solve a more complex version of the GT, participants without WM load performed well, while participants with WM load performed poorly. In Study 3, where the complexity of the GT was further increased, participants in both conditions performed poorly. In addition to the standard performance measure, we used participants' subjective expected utility, showing that it differs from the standard measure in some important aspects.

  7. Adaptive Working Memory Training Reduces the Negative Impact of Anxiety on Competitive Motor Performance.

    PubMed

    Ducrocq, Emmanuel; Wilson, Mark; Smith, Tim J; Derakshan, Nazanin

    2017-12-01

    Optimum levels of attentional control are essential to prevent athletes from experiencing performance breakdowns under pressure. The current study explored whether training attentional control using the adaptive dual n-back paradigm, designed to directly target processing efficiency of the main executive functions of working memory (WM), would result in transferrable effects on sports performance outcomes. A total of 30 tennis players were allocated to an adaptive WM training or active control group and underwent 10 days of training. Measures of WM capacity as well as performance and objective gaze indices of attentional control in a tennis volley task were assessed in low- and high-pressure posttraining conditions. Results revealed significant benefits of training on WM capacity, quiet eye offset, and tennis performance in the high-pressure condition. Our results confirm and extend previous findings supporting the transfer of cognitive training benefits to objective measures of sports performance under pressure.

  8. Real-time fMRI training-induced changes in regional connectivity mediating verbal working memory behavioral performance.

    PubMed

    Shen, J; Zhang, G; Yao, L; Zhao, X

    2015-03-19

    Working memory refers to the ability to temporarily store and manipulate information that is necessary for complex cognition activities. Previous studies have demonstrated that working memory capacity can be improved by behavioral training, and brain activities in the frontal and parietal cortices and the connections between these regions are also altered by training. Our recent neurofeedback training has proven that the regulation of the left dorsal lateral prefrontal cortex (DLPFC) activity using real-time functional magnetic resonance imaging (rtfMRI) can improve working memory performance. However, how working memory training promotes interaction between brain regions and whether this promotion correlates with performance improvement remain unclear. In this study, we employed structural equation modeling (SEM) to calculate the interactions between the regions within the working memory network during neurofeedback training. The results revealed that the direct effect of the frontoparietal connection in the left hemisphere was enhanced by the rtfMRI training. Specifically, the increase in the path from the left DLPFC to the left inferior parietal lobule (IPL) was positively correlated with improved performance in verbal working memory. These findings demonstrate the important role of the frontoparietal connection in working memory training and suggest that increases in frontoparietal connectivity might be a key factor associated with behavioral improvement. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Feature Selection for Chemical Sensor Arrays Using Mutual Information

    PubMed Central

    Wang, X. Rosalind; Lizier, Joseph T.; Nowotny, Thomas; Berna, Amalia Z.; Prokopenko, Mikhail; Trowell, Stephen C.

    2014-01-01

    We address the problem of feature selection for classifying a diverse set of chemicals using an array of metal oxide sensors. Our aim is to evaluate a filter approach to feature selection with reference to previous work, which used a wrapper approach on the same data set, and established best features and upper bounds on classification performance. We selected feature sets that exhibit the maximal mutual information with the identity of the chemicals. The selected features closely match those found to perform well in the previous study using a wrapper approach to conduct an exhaustive search of all permitted feature combinations. By comparing the classification performance of support vector machines (using features selected by mutual information) with the performance observed in the previous study, we found that while our approach does not always give the maximum possible classification performance, it always selects features that achieve classification performance approaching the optimum obtained by exhaustive search. We performed further classification using the selected feature set with some common classifiers and found that, for the selected features, Bayesian Networks gave the best performance. Finally, we compared the observed classification performances with the performance of classifiers using randomly selected features. We found that the selected features consistently outperformed randomly selected features for all tested classifiers. The mutual information filter approach is therefore a computationally efficient method for selecting near optimal features for chemical sensor arrays. PMID:24595058

  10. The Association between Meditation Practice and Job Performance: A Cross-Sectional Study.

    PubMed

    Shiba, Koichiro; Nishimoto, Masahiro; Sugimoto, Minami; Ishikawa, Yoshiki

    2015-01-01

    Many previous studies have shown that meditation practice has a positive impact on cognitive and non-cognitive functioning, which are related to job performance. Thus, the aims of this study were to (1) estimate the prevalence of meditation practice, (2) identify the characteristics of individuals who practice meditation, and (3) examine the association between meditation practice and job performance. Two population-based, cross-sectional surveys were conducted. In study 1, we examined the prevalence of meditation practice and the characteristics of the persons practicing meditation; in Study 2, we examined the association between meditation practice and job performance. The outcome variables included work engagement, subjective job performance, and job satisfaction. The Utrecht Work Engagement Scale was used to assess work engagement, the World Health Organization Health and Work Performance Questionnaire (HPQ) was used to measure subjective job performance, and a scale developed by the Japanese government was used to assess job satisfaction. Hierarchical multiple regression analyses were used in Study 2. Demographic characteristics and behavioral risk factors were included as covariates in the analyses. The results of Study 1 indicated that 3.9% of persons surveyed (n = 30,665) practiced meditation; these individuals were younger and had a higher education, higher household income, higher stress level, and lower body mass index than those who did not practice meditation. The results of Study 2 (n = 1,470) indicated that meditation practice was significantly predictive of work engagement (β = 0.112, p < .001), subjective job performance (β = 0.116, p < .001), and job satisfaction (β = 0.079, p = .002), even after adjusting for covariates (β = 0.083, p < .001; β = 0.104, p < .001; β = 0.060, p = .015, respectively). The results indicate that meditation practice may positively influence job performance, including job satisfaction, subjective job performance, and work engagement.

  11. Responses to different types of inquiry prompts: college students' discourse, performance, and perceptions of group work in an engineering class

    NASA Astrophysics Data System (ADS)

    Balgopal, Meena M.; Casper, Anne Marie A.; Atadero, Rebecca A.; Rambo-Hernandez, Karen E.

    2017-08-01

    Working in small groups to solve problems is an instructional strategy that allows university students in science, technology, engineering, and mathematics disciplines the opportunity to practice interpersonal and professional skills while gaining and applying discipline-specific content knowledge. Previous research indicates that not all group work prompts result in the same experiences for students. In this study we posed two types of prompts (guided and open) to undergraduate engineering students in a statics course as they participated in group work projects. We measured student discourse, student performance, and perceptions of group work. We found that guided prompts were associated with higher-level discourse and higher performance (project scores) than open prompts. Students engaged in guided prompts were more likely to discuss distribution of labour and design/calculation details of their projects than when students responded to open prompts. We posit that guided prompts, which more clearly articulate expectations of students, help students determine how to divide tasks amongst themselves and, subsequently, jump to higher levels of discourse.

  12. Design of mathematical models assessment of working achievements based on spencer competency in PT. Z

    NASA Astrophysics Data System (ADS)

    Siregar, K.; Siregar, S. F.

    2018-02-01

    This research is design employee performance assessment by considering work result of employee based on competency. Relevant competencies are identified according to Spencer’s competence of employees that subsequently processed by Analytical Hierarchy Process (AHP) method. The results of weighting AHP indicate the highest priority order of criteria, there are; concern of customer satisfaction (0.1325), group work (0.1324) and technical expertise (0.0826). The weight of the criteria is used to design the Work Performance Value (WPV) to be used as the basis for calculating the incentive index. The higher incentive index of an employee, the greater amount of incentives was earned. The calculation of incentives is made to four employees of chopsticks production. From employee incentives A, B, C and D, employee D has the highest incentive index and increment of IDR 2,700,675 compared to previous incentive system. The incentive division system based on the Work Performance Values (WPV) of this proposal reflects a real incentive so that the incapacity of incentive can be reduced.

  13. The stability of working memory: do previous tasks influence complex span?

    PubMed

    Healey, M Karl; Hasher, Lynn; Danilova, Elena

    2011-11-01

    Schmeichel (2007) reported that performing an initial task before completing a working memory span task can lower span scores and suggested that the effect was due to depleted cognitive resources. We showed that the detrimental effect of prior tasks depends on a match between the stimuli used in the span task and the preceding task. A task requiring participants to ignore words reduced performance on a subsequent word-based verbal span task but not on an arrow-based spatial span task. Ignoring arrows had the opposite pattern of effects: reducing performance on the spatial span task but not on the word-based span task. Finally, we showed that antisaccade, a nonverbal task that taxes domain-general processes implicated in working memory, did not influence subsequent performance of either a verbal or a spatial span task. Together these results suggest that while span is sensitive to prior tasks, that sensitivity does not stem from depleted resources. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

  14. Tart cherries improve working memory in aged rats

    USDA-ARS?s Scientific Manuscript database

    Aged rats show impaired performance on cognitive tasks that require the use of spatial learning and memory. In previous studies, we have shown the beneficial effects of various dark-colored berry fruits (blueberries, strawberries, and blackberries) in reversing age-related deficits in behavioral and...

  15. Does Technology Acceptance Affect E-Learning in a Non-Technology-Intensive Course?

    ERIC Educational Resources Information Center

    Buche, Mari W.; Davis, Larry R.; Vician, Chelley

    2012-01-01

    Prior research suggests that individuals' technology acceptance levels may affect their work and learning performance outcomes when activities are conducted through information technology usage. Most previous research investigating the relationship between individual attitudes towards technology and learning has been conducted in…

  16. Role of U(VI) Adsorption in U(VI) Reduction by Geobacter Species.

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

    None, None

    2009-03-09

    Previous work had suggested that Acholeplasma palmae has a higher capacity for uranium sorption than other bacteria studied. Sorption studies were performed with cells in suspension in various solutions containing uranium and results were used to generate uranium-biosorption isotherms.

  17. Contextualizing Attitudes toward Pronunciation: Foreign Language Learners in the United States

    ERIC Educational Resources Information Center

    Huensch, Amanda; Thompson, Amy S.

    2017-01-01

    While previous work has shown a relationship between pronunciation attitudes and pronunciation performance, the connection between language learning motivation and pronunciation attitudes has been underexplored. This study investigated the relationship between 195 foreign language learners' attitudes toward pronunciation, the foreign languages…

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

    Metz, Lori A.; Friese, Judah I.; Finn, Erin C.

    Critical assemblies provide one method of achieving a fast neutron spectrum that is close to a 235U fission-energy neutron spectrum for nuclear data measurements. Previous work has demonstrated the use of a natural boron carbide capsule for spectral-tailoring in a mixed spectrum reactor as an alternate and complementary method for performing fission-energy neutron experiments. Previous fission products measurements showed that the neutron spectrum achievable with natural boron carbide was not as hard as what can be achieved with critical assemblies. New measurements performed with the Washington State University TRIGA reactor using a boron carbide capsule 96% enriched in 10B formore » irradiations resulted in a neutron spectrum very similar to a critical assembly and a pure 235U fission spectrum. The current work describes an experiment involving a highly-enriched uranium target irradiated under the new 10B4C capsule. Fission product yields were measured following radiochemical separations and are presented here. Reactor dosimetry measurements for characterizing neutron spectra and fluence for the enriched boron carbide capsule and critical assemblies are also discussed.« less

  19. Upgrade of the TITAN EBIT High Voltage Operation

    NASA Astrophysics Data System (ADS)

    Foster, Matt; Titan Collaboration

    2016-09-01

    TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) is a setup dedicated to highly precise mass measurements of short-lived isotopes down to 10ms. TITAN's Electron Beam Ion Trap (EBIT) is a charge breeder integrated into the setup to perform in-trap decay spectroscopy of highly charged ions and increase the precision of mass measurements. In its previous configuration TITAN's EBIT could not fulfil its maximum design specification due to high voltage safety restrictions, limiting its obtainable charge states. A recently completed upgrade of the high voltage operation that will allow the EBIT to fulfil its design specification and achieve higher charge states for heavier species is undergoing preliminary tests with stable beam. Simulations were performed to optimise the injection and extraction efficiency at high voltage and initial tests have involved using a Ge detector to identify x-rays produced by charge breeding stable ions. Future work comprises exploring electron capture rates of Ne-, He- and H-like charge states of 64Cu and higher masses, which were not previously accessible. The function of the EBIT within the TITAN setup, the work carried out on the upgrade thus far and its scope for future work will be presented.

  20. Femtosecond Polarization Phase Selective (PPS) High Magnetic Field Studies of Electron-Spin-Hole (ESH) Dynamics: New Tools for Ultrafast Imaging Fe-centered ESH Transfer Mechanisms Steps

    NASA Astrophysics Data System (ADS)

    Rupnik, Kresimir; Cooper, Benjamin; Dunne, Taylor; Gerosa, Katherine; Mercer, Kaitlyn; McGill, Stephen

    In previous work, new Nanoparticle-enzyme Based Hybrids (NEBH) synthesis methods were investigated for nanoparticles of different shapes and electron energies. These hybrids can provide electromagnetic-field-driven ESH separations and transfers to desired molecular locations. Of paramount biomedical interest are the activity centers (including Fe-clusters) in proteins that perform their intended function and help synthesize other molecules. In this work we discuss results of our recent in situ ESH dynamics measurements: we use <15fs (Vitara) PPS broad band pulses and ultrahigh, 25T, magnetic fields from Split-helix magnet at NHMFL. Work included multi-spectral domain PPS harmonic generations and PPS sum frequency generations. Model compounds, including cytochromes, were used for testing and calibrations and previously studied Fe-S enzymes were prepared for measurements. While PPS opto-magnetic methods are known for their insight into electronic structure, our femtosecond measurements can provide ultrafast dynamic imaging of ESH mechanisms decision making steps. UF-PPS Project, performed in part at NHMFL, supported by NSF CA No. DMR-1157490, and 0654118 and U.S. DOE.

  1. Linking working memory and long-term memory: a computational model of the learning of new words.

    PubMed

    Jones, Gary; Gobet, Fernand; Pine, Julian M

    2007-11-01

    The nonword repetition (NWR) test has been shown to be a good predictor of children's vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children's vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model's behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity.

  2. High efficiency IR supercontinuum generation and applications: a recent review

    NASA Astrophysics Data System (ADS)

    Yin, Shizhuo; Ruffin, Paul; Brantley, Christina; Edwards, Eugene; Cheng, Jiping; Luo, Claire

    2012-10-01

    In this paper, we have reviewed our recent works on IR supercontinuum generation (SCG) and its applications. First, we provide a brief review on the physical mechanism of the supercontinuum generation and our previous works in this field. Second, a thinner IR crystal fiber is fabricated. The supercontinuum generation in this thinner fiber is also demonstrated, which shows the enhanced performance. The suggestion for the future effort is also included.

  3. Camp Upshur, Marine Corps Base Quantico, VA Architectural Survey

    DTIC Science & Technology

    2009-08-01

    MIPR) M9301509MPFE007, dated 21 November 2008. The MCB Quantico technical monitor was John Haynes, Archeologist. The work was performed by the...Manager was Adam Smith. Dr. Christopher White is Chief, CN-C, and Dr. John Bandy is Chief, CN. The Deputy Director of CERL is Dr. Kirankumar V...Previous work reported in “Historical Resource Survey and Evaluation, Marine Corps Base Quantico, Virginia” John Milner Associates, 2008 and on

  4. Performance of VPIC on Sequoia

    NASA Astrophysics Data System (ADS)

    Nystrom, William

    2014-10-01

    Sequoia is a major DOE computing resource which is characteristic of future resources in that it has many threads per compute node, 64, and the individual processor cores are simpler and less powerful than cores on previous processors like Intel's Sandy Bridge or AMD's Opteron. An effort is in progress to port VPIC to the Blue Gene Q architecture of Sequoia and evaluate its performance. Results of this work will be presented on single node performance of VPIC as well as multi-node scaling.

  5. Performance comparison of leading image codecs: H.264/AVC Intra, JPEG2000, and Microsoft HD Photo

    NASA Astrophysics Data System (ADS)

    Tran, Trac D.; Liu, Lijie; Topiwala, Pankaj

    2007-09-01

    This paper provides a detailed rate-distortion performance comparison between JPEG2000, Microsoft HD Photo, and H.264/AVC High Profile 4:4:4 I-frame coding for high-resolution still images and high-definition (HD) 1080p video sequences. This work is an extension to our previous comparative study published in previous SPIE conferences [1, 2]. Here we further optimize all three codecs for compression performance. Coding simulations are performed on a set of large-format color images captured from mainstream digital cameras and 1080p HD video sequences commonly used for H.264/AVC standardization work. Overall, our experimental results show that all three codecs offer very similar coding performances at the high-quality, high-resolution setting. Differences tend to be data-dependent: JPEG2000 with the wavelet technology tends to be the best performer with smooth spatial data; H.264/AVC High-Profile with advanced spatial prediction modes tends to cope best with more complex visual content; Microsoft HD Photo tends to be the most consistent across the board. For the still-image data sets, JPEG2000 offers the best R-D performance gains (around 0.2 to 1 dB in peak signal-to-noise ratio) over H.264/AVC High-Profile intra coding and Microsoft HD Photo. For the 1080p video data set, all three codecs offer very similar coding performance. As in [1, 2], neither do we consider scalability nor complexity in this study (JPEG2000 is operating in non-scalable, but optimal performance mode).

  6. Fast globally optimal segmentation of cells in fluorescence microscopy images.

    PubMed

    Bergeest, Jan-Philip; Rohr, Karl

    2011-01-01

    Accurate and efficient segmentation of cells in fluorescence microscopy images is of central importance for the quantification of protein expression in high-throughput screening applications. We propose a new approach for segmenting cell nuclei which is based on active contours and convex energy functionals. Compared to previous work, our approach determines the global solution. Thus, the approach does not suffer from local minima and the segmentation result does not depend on the initialization. We also suggest a numeric approach for efficiently computing the solution. The performance of our approach has been evaluated using fluorescence microscopy images of different cell types. We have also performed a quantitative comparison with previous segmentation approaches.

  7. Business owners' optimism and business performance after a natural disaster.

    PubMed

    Bronson, James W; Faircloth, James B; Valentine, Sean R

    2006-12-01

    Previous work indicates that individuals' optimism is related to superior performance in adverse situations. This study examined correlations after flooding for measures of business recovery but found only weak support (very small common variance) for business owners' optimism scores and sales recovery. Using traditional measures of recovery, in this study was little empirical evidence that optimism would be of value in identifying businesses at risk after a natural disaster.

  8. Shift Work and Cognitive Flexibility: Decomposing Task Performance.

    PubMed

    Cheng, Philip; Tallent, Gabriel; Bender, Thomas John; Tran, Kieulinh Michelle; Drake, Christopher L

    2017-04-01

    Deficits in cognitive functioning associated with shift work are particularly relevant to occupational performance; however, few studies have examined how cognitive functioning is associated with specific components of shift work. This observational study examined how circadian phase, nocturnal sleepiness, and daytime insomnia in a sample of shift workers ( N = 30) were associated with cognitive flexibility during the night shift. Cognitive flexibility was measured using a computerized task-switching paradigm, which produces 2 indexes of flexibility: switch cost and set inhibition. Switch cost represents the additional cognitive effort required in switching to a different task and can impact performance when multitasking is involved. Set inhibition is the efficiency in returning to previously completed tasks and represents the degree of cognitive perseveration, which can lead to reduced accuracy. Circadian phase was measured via melatonin assays, nocturnal sleepiness was assessed using the Multiple Sleep Latency Test, and daytime insomnia was assessed using the Insomnia Severity Index. Results indicated that those with an earlier circadian phase, insomnia, and sleepiness exhibited reduced cognitive flexibility; however, specific components of cognitive flexibility were differentially associated with circadian phase, insomnia, and sleepiness. Individuals with an earlier circadian phase (thus more misaligned to the night shift) exhibited larger switch costs, which was also associated with reduced task efficiency. Shift workers with more daytime insomnia demonstrated difficulties with cognitive inhibition, whereas nocturnal sleepiness was associated with difficulties in reactivating previous tasks. Deficits in set inhibition were also related to reduced accuracy and increased perseverative errors. Together, this study indicates that task performance deficits in shift work are complex and are variably impacted by different mechanisms. Future research may examine phenotypic differences in shift work and the associated consequences. Results also suggest that fatigue risk management strategies may benefit from increased scope and specificity in assessment of sleep, sleepiness, and circadian rhythms in shift workers.

  9. ORCA Project: Research on high-performance parallel computer programming environments. Final report, 1 Apr-31 Mar 90

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

    Snyder, L.; Notkin, D.; Adams, L.

    1990-03-31

    This task relates to research on programming massively parallel computers. Previous work on the Ensamble concept of programming was extended and investigation into nonshared memory models of parallel computation was undertaken. Previous work on the Ensamble concept defined a set of programming abstractions and was used to organize the programming task into three distinct levels; Composition of machine instruction, composition of processes, and composition of phases. It was applied to shared memory models of computations. During the present research period, these concepts were extended to nonshared memory models. During the present research period, one Ph D. thesis was completed, onemore » book chapter, and six conference proceedings were published.« less

  10. Full-scale tank car rollover tests - survivability of top fittings and top fittings protective structures : final report.

    DOT National Transportation Integrated Search

    2016-05-01

    Full-scale rollover crash tests were performed on three non-pressure tank carbodies to validate previous analytical work and : determine the effectiveness of two different types of protective structures in protecting the top fittings. The tests were ...

  11. An Examination of the Relationship between Motor Coordination and Executive Functions in Adolescents

    ERIC Educational Resources Information Center

    Rigoli, Daniela; Piek, Jan P.; Kane, Robert; Oosterlaan, Jaap

    2012-01-01

    Aim: Research suggests important links between motor coordination and executive functions. The current study examined whether motor coordination predicts working memory, inhibition, and switching performance, extending previous research by accounting for attention-deficit-hyperactivity disorder (ADHD) symptomatology and other confounding factors,…

  12. Propagation analysis of transverse defects originating at the lower gage corner of rail

    DOT National Transportation Integrated Search

    1998-12-01

    This report describes analyses performed to examine the growth rate of a particular transverse defect that forms in the rail head. The most common transverse defect found in rail, known as the detail fracture, has been studied in previous work. The p...

  13. Oscillating-flow regenerator test rig

    NASA Technical Reports Server (NTRS)

    Wood, J. G.; Gedeon, D. R.

    1994-01-01

    This report summarizes work performed in setting up and performing tests on a regenerator test rig. An earlier status report presented test results, together with heat transfer correlations, for four regenerator samples (two woven screen samples and two felt metal samples). Lessons learned from this testing led to improvements to the experimental setup, mainly instrumentation as well as to the test procedure. Given funding and time constraints for this project it was decided to complete as much testing as possible while the rig was set up and operational, and to forego final data reduction and analysis until later. Additional testing was performed on several of the previously tested samples as well an on five newly fabricated samples. The following report is a summary of the work performed at OU, with many of the final test results included in raw data form.

  14. Tactile perception and working memory in rats and humans

    PubMed Central

    Fassihi, Arash; Akrami, Athena; Esmaeili, Vahid; Diamond, Mathew E.

    2014-01-01

    Primates can store sensory stimulus parameters in working memory for subsequent manipulation, but until now, there has been no demonstration of this capacity in rodents. Here we report tactile working memory in rats. Each stimulus is a vibration, generated as a series of velocity values sampled from a normal distribution. To perform the task, the rat positions its whiskers to receive two such stimuli, “base” and “comparison,” separated by a variable delay. It then judges which stimulus had greater velocity SD. In analogous experiments, humans compare two vibratory stimuli on the fingertip. We demonstrate that the ability of rats to hold base stimulus information (for up to 8 s) and their acuity in assessing stimulus differences overlap the performance demonstrated by humans. This experiment highlights the ability of rats to perceive the statistical structure of vibrations and reveals their previously unknown capacity to store sensory information in working memory. PMID:24449850

  15. Final Report for Annex II--Assessment of Solar Radiation Resources In Saudi Arabia, 1998-2000

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

    Myers, D. R.; Wilcox, S. M.; Marion, W. F.

    2002-04-01

    The Final Report for Annex II - Assessment of Solar Radiation Resources in Saudi Arabia 1998-2000 summarizes the accomplishment of work performed, results achieved, and products produced under Annex II, a project established under the Agreement for Cooperation in the Field of Renewable Energy Research and Development between the Kingdom of Saudi Arabia and the United States. The report covers work and accomplishments from January 1998 to December 2000. A previous progress report, Progress Report for Annex II - Assessment of Solar Radiation Resources in Saudi Arabia 1993-1997, NREL/TP-560-29374, summarizes earlier work and technical transfer of information under the project.more » The work was performed in at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, at the King Abdulaziz City for Science and Technology (KACST) in Riyadh, Saudi Arabia, and at selected weather stations of the Saudi Meteorological and Environmental Protection Administration (MEPA).« less

  16. Chronic pain, work performance and litigation.

    PubMed

    Blyth, Fiona M; March, Lyn M; Nicholas, Michael K; Cousins, Michael J

    2003-05-01

    The overall population impact of chronic pain on work performance has been underestimated as it has often been described in terms of work-related absence, excluding more subtle effects that chronic pain may have on the ability to work effectively. Additionally, most studies have focussed on occupational and/or patient cohorts and treatment seeking, rather than sampling from the general population. We undertook a population-based random digit dialling computer-assisted telephone survey with participants randomly selected within households in order to measure the impact of chronic pain on work performance. In addition, we measured the association between pain-related disability and litigation. The study took place in Northern Sydney Health Area, a geographically defined urban area of New South Wales, Australia, and included 484 adults aged 18 or over with chronic pain. The response rate was 73.4%. Working with pain was more common (on an average 83.8 days in 6 months) than lost work days due to pain (4.5 days) among chronic pain participants in full-time or part-time employment. When both lost work days and reduced-effectiveness work days were summed, an average of 16.4 lost work day equivalents occurred in a 6-month period, approximately three times the average number of lost work days. In multiple logistic regression modelling with pain-related disability as the dependent variable, past or present pain-related litigation had the strongest association (odds ratio (OR)=3.59, P=0.001). In conclusion, chronic pain had a larger impact on work performance than has previously been recognised, related to reduced performance while working with pain. A significant proportion were able to work effectively with pain, suggesting that complete relief of pain may not be an essential therapeutic target. Litigation (principally work-related) for chronic pain was strongly associated with higher levels of pain-related disability, even after taking into account other factors associated with poor functional outcomes.

  17. Mission possible? The performance of prosocially motivated employees depends on manager trustworthiness.

    PubMed

    Grant, Adam M; Sumanth, John J

    2009-07-01

    The authors propose that in mission-driven organizations, prosocially motivated employees are more likely to perform effectively when trust cues enhance their perceptions of task significance. The authors develop and test a model linking prosocial motivation, trust cues, task significance, and performance across 3 studies of fundraisers using 3 different objective performance measures. In Study 1, perceiving managers as trustworthy strengthened the relationship between employees' prosocial motivation and performance, measured in terms of calls made. This moderated relationship was mediated by employees' perceptions of task significance. Study 2 replicated the interaction of manager trustworthiness and prosocial motivation in predicting a new measure of performance: dollars raised. It also revealed 3-way interactions between prosocial motivation, manager trustworthiness, and dispositional trust propensity, such that high trust propensity compensated for low manager trustworthiness to strengthen the association between employees' prosocial motivation and performance. Study 3 replicated all of the previous mediation and moderation findings in predicting initiative taken by professional fundraisers. Implications for work motivation, work design, and trust in organizations are discussed.

  18. Analysis of Aurora's Performance Simulation Engine for Three Systems

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

    Freeman, Janine; Simon, Joseph

    2015-07-07

    Aurora Solar Inc. is building a cloud-based optimization platform to automate the design, engineering, and permit generation process of solar photovoltaic (PV) installations. They requested that the National Renewable Energy Laboratory (NREL) validate the performance of the PV system performance simulation engine of Aurora Solar’s solar design platform, Aurora. In previous work, NREL performed a validation of multiple other PV modeling tools 1, so this study builds upon that work by examining all of the same fixed-tilt systems with available module datasheets that NREL selected and used in the aforementioned study. Aurora Solar set up these three operating PV systemsmore » in their modeling platform using NREL-provided system specifications and concurrent weather data. NREL then verified the setup of these systems, ran the simulations, and compared the Aurora-predicted performance data to measured performance data for those three systems, as well as to performance data predicted by other PV modeling tools.« less

  19. Is less really more: Does a prefrontal efficiency genotype actually confer better performance when working memory becomes difficult?

    PubMed

    Ihne, Jessica L; Gallagher, Natalie M; Sullivan, Marie; Callicott, Joseph H; Green, Adam E

    2016-01-01

    Perhaps the most widely studied effect to emerge from the combination of neuroimaging and human genetics is the association of the COMT-Val(108/158)Met polymorphism with prefrontal activity during working memory. COMT-Val is a putative risk factor in schizophrenia, which is characterized by disordered prefrontal function. Work in healthy populations has sought to characterize mechanisms by which the valine (Val) allele may lead to disadvantaged prefrontal cognition. Lower activity in methionine (Met) carriers has been interpreted as advantageous neural efficiency. Notably, however, studies reporting COMT effects on neural efficiency have generally not reported working memory performance effects. Those studies have employed relatively low/easy working memory loads. Higher loads are known to elicit individual differences in working memory performance that are not visible at lower loads. If COMT-Met confers greater neural efficiency when working memory is easy, a reasonable prediction is that Met carriers will be better able to cope with increasing demand for neural resources when working memory becomes difficult. To our knowledge, this prediction has thus far gone untested. Here, we tested performance on three working memory tasks. Performance on each task was measured at multiple levels of load/difficulty, including loads more demanding than those used in prior studies. We found no genotype-by-load interactions or main effects of COMT genotype on accuracy or reaction time. Indeed, even testing for performance differences at each load of each task failed to find a single significant effect of COMT genotype. Thus, even if COMT genotype has the effects on prefrontal efficiency that prior work has suggested, such effects may not directly impact high-load working memory ability. The present findings accord with previous evidence that behavioral effects of COMT are small or nonexistent and, more broadly, with a growing consensus that substantial effects on phenotype will not emerge from candidate gene studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Wing Shaping and Gust Load Controls of Flexible Aircraft: An LPV Approach

    NASA Technical Reports Server (NTRS)

    Hammerton, Jared R.; Su, Weihua; Zhu, Guoming; Swei, Sean Shan-Min

    2018-01-01

    In the proposed paper, the optimum wing shape of a highly flexible aircraft under varying flight conditions will be controlled by a linear parameter-varying approach. The optimum shape determined under multiple objectives, including flight performance, ride quality, and control effort, will be determined as well. This work is an extension of work done previously by the authors, and updates the existing optimization and utilizes the results to generate a robust flight controller.

  1. Targeted Approach to Overcoming Treatment Resistance in Advanced Prostate Cancer

    DTIC Science & Technology

    2013-07-01

    molecular   dynamics  as  in  our  previous  works  (Vasilyeva,  A  et  al,  2009;  Vasilyeva,  A   et...results  and  pitfalls.     Molecular  docking  experiments  were  performed  as   follows:   The   molecular  docking  was...al,  2010;Salsbury.  2010).  However,  for  this  work  more  extensive   simulations

  2. Dissociating rehearsal and refreshing in the maintenance of verbal information in 8-year-old children

    PubMed Central

    Mora, Gérome; Camos, Valérie

    2015-01-01

    Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Camos et al., 2009; Baddeley, 2012). Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children ( Tam et al., 2010). The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect (PSE) differed from what is observed in adults. Whereas the PSE relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the PSE. PMID:25667577

  3. Dissociating rehearsal and refreshing in the maintenance of verbal information in 8-year-old children.

    PubMed

    Mora, Gérome; Camos, Valérie

    2015-01-01

    Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Camos et al., 2009; Baddeley, 2012). Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children ( Tam et al., 2010). The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect (PSE) differed from what is observed in adults. Whereas the PSE relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the PSE.

  4. Proactive Interference Does Not Meaningfully Distort Visual Working Memory Capacity Estimates in the Canonical Change Detection Task

    PubMed Central

    Lin, Po-Han; Luck, Steven J.

    2012-01-01

    The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task – in which the to-be-remembered information consists of simple, briefly presented features – is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference. PMID:22403556

  5. Proactive interference does not meaningfully distort visual working memory capacity estimates in the canonical change detection task.

    PubMed

    Lin, Po-Han; Luck, Steven J

    2012-01-01

    The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task - in which the to-be-remembered information consists of simple, briefly presented features - is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference.

  6. Mechanical Validation of an MRI Compatible Stereotactic Neurosurgery Robot in Preparation for Pre-Clinical Trials.

    PubMed

    Nycz, Christopher J; Gondokaryono, Radian; Carvalho, Paulo; Patel, Nirav; Wartenberg, Marek; Pilitsis, Julie G; Fischer, Gregory S

    2017-09-01

    The use of magnetic resonance imaging (MRI) for guiding robotic surgical devices has shown great potential for performing precisely targeted and controlled interventions. To fully realize these benefits, devices must work safely within the tight confines of the MRI bore without negatively impacting image quality. Here we expand on previous work exploring MRI guided robots for neural interventions by presenting the mechanical design and assessment of a device for positioning, orienting, and inserting an interstitial ultrasound-based ablation probe. From our previous work we have added a 2 degree of freedom (DOF) needle driver for use with the aforementioned probe, revised the mechanical design to improve strength and function, and performed an evaluation of the mechanism's accuracy and effect on MR image quality. The result of this work is a 7-DOF MRI robot capable of positioning a needle tip and orienting it's axis with accuracy of 1.37 ± 0.06 mm and 0.79° ± 0.41°, inserting it along it's axis with an accuracy of 0.06 ± 0.07 mm , and rotating it about it's axis to an accuracy of 0.77° ± 1.31°. This was accomplished with no significant reduction in SNR caused by the robot's presence in the MRI bore, ≤ 10.3% reduction in SNR from running the robot's motors during a scan, and no visible paramagnetic artifacts.

  7. A Closer Look at Manipulatives in Remediation

    ERIC Educational Resources Information Center

    Peppers, Denise S.; Wan, Anna; Phillips, Hope E.

    2014-01-01

    In this article, one teacher describes her action research with eighth-grade prealgebra students who are working on a conceptual understanding of fractions. Examining her middle school students' standardized test scores for the previous five years, Denise S. Peppers discovered that student performance on fractions was consistently the lowest…

  8. Solving Large Problems with a Small Working Memory

    ERIC Educational Resources Information Center

    Pizlo, Zygmunt; Stefanov, Emil

    2013-01-01

    We describe an important elaboration of our multiscale/multiresolution model for solving the Traveling Salesman Problem (TSP). Our previous model emulated the non-uniform distribution of receptors on the human retina and the shifts of visual attention. This model produced near-optimal solutions of TSP in linear time by performing hierarchical…

  9. Modulation of Global and Local Processing Biases in Adults with Autistic-Like Traits

    ERIC Educational Resources Information Center

    English, Michael C. W.; Maybery, Murray T.; Visser, Troy A. W.

    2017-01-01

    Previous work shows that doing a continuous performance task (CPT) shifts attentional biases in neurotypical individuals towards global aspects of hierarchical Navon figures by selectively activating right hemisphere regions associated with global processing. The present study examines whether CPT can induce similar modulations of attention in…

  10. Problem Solving Under Time-Constraints.

    ERIC Educational Resources Information Center

    Richardson, Michael; Hunt, Earl

    A model of how automated and controlled processing can be mixed in computer simulations of problem solving is proposed. It is based on previous work by Hunt and Lansman (1983), who developed a model of problem solving that could reproduce the data obtained with several attention and performance paradigms, extending production-system notation to…

  11. What Motivates the Motivators? An Examination of Sports Coaches

    ERIC Educational Resources Information Center

    McLean, Kristy N.; Mallett, Clifford J.

    2012-01-01

    Background: Motivation is central to successful performance. In the case of sports coaches, drive is a prerequisite to sustained successful engagement in a complex, dynamic, and turbulent work environment. What fuels these coaches' drive to pursue this vocational activity? Coach motivation has been underrepresented in previous research which has…

  12. Enhanced effects of cortisol administration on episodic and working memory in aging veterans with PTSD.

    PubMed

    Yehuda, Rachel; Harvey, Philip D; Buchsbaum, Monte; Tischler, Lisa; Schmeidler, James

    2007-12-01

    Though both glucocorticoid alterations and memory impairments have been noted in posttraumatic stress disorder (PTSD), it is not clear if these phenomena are causally linked. As there is emerging evidence that these domains become further altered in PTSD with increasing age, it is of interest to examine these relationships in an older cohort. Aging (mean age, 62.7+/-8.9; range, 52-81) combat veterans with (n=13) and without (n=17) PTSD received an intravenous bolus of 17.5 mg hydrocortisone (cortisol), a naturally occurring glucocorticoid, or placebo in a randomized, double-blind manner, on two mornings approximately 1-2 weeks apart. Neuropsychological testing to evaluate episodic and working memory performance was performed 75 min later. Cortisol enhanced episodic memory performance in both groups of subjects, but enhanced elements of working memory performance only in the PTSD+ group. The preferential effect of cortisol administration on working memory in PTSD may be related to the superimposition of PTSD and age, as cortisol had impairing effects on this task in a previously studied, younger cohort. The findings suggest that there may be opportunities for developing therapeutic strategies using glucocorticoids in the treatment of aging combat veterans.

  13. The role of expressive writing in math anxiety.

    PubMed

    Park, Daeun; Ramirez, Gerardo; Beilock, Sian L

    2014-06-01

    Math anxiety is a negative affective reaction to situations involving math. Previous work demonstrates that math anxiety can negatively impact math problem solving by creating performance-related worries that disrupt the working memory needed for the task at hand. By leveraging knowledge about the mechanism underlying the math anxiety-performance relationship, we tested the effectiveness of a short expressive writing intervention that has been shown to reduce intrusive thoughts and improve working memory availability. Students (N = 80) varying in math anxiety were asked to sit quietly (control group) prior to completing difficulty-matched math and word problems or to write about their thoughts and feelings regarding the exam they were about to take (expressive writing group). For the control group, high math-anxious individuals (HMAs) performed significantly worse on the math problems than low math-anxious students (LMAs). In the expressive writing group, however, this difference in math performance across HMAs and LMAs was significantly reduced. Among HMAs, the use of words related to anxiety, cause, and insight in their writing was positively related to math performance. Expressive writing boosts the performance of anxious students in math-testing situations. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  14. Cognitive precursors of arithmetic development in primary school children with cerebral palsy.

    PubMed

    Van Rooijen, M; Verhoeven, L; Smits, D W; Dallmeijer, A J; Becher, J G; Steenbergen, B

    2014-04-01

    The aim of this study was to examine the development of arithmetic performance and its cognitive precursors in children with CP from 7 till 9 years of age. Previous research has shown that children with CP are generally delayed in arithmetic performance compared to their typically developing peers. In children with CP, the developmental trajectory of the ability to solve addition- and subtraction tasks has, however, rarely been studied, as well as the cognitive factors affecting this trajectory. Sixty children (M=7.2 years, SD=.23 months at study entry) with CP participated in this study. Standardized tests were administered to assess arithmetic performance, word decoding skills, non-verbal intelligence, and working memory. The results showed that the ability to solve addition- and subtraction tasks increased over a two year period. Word decoding skills were positively related to the initial status of arithmetic performance. In addition, non-verbal intelligence and working memory were associated with the initial status and growth rate of arithmetic performance from 7 till 9 years of age. The current study highlights the importance of non-verbal intelligence and working memory to the development of arithmetic performance of children with CP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Framework for Instructional Technology: Methods of Implementing Adaptive Training and Education

    DTIC Science & Technology

    2014-01-01

    with when they were correct and certain, performed better on a posttest than students who got the same (positive) feedback for every correct...analogous step in previous examples. Students in this condition performed better on a posttest than students who had received fading of worked examples...well on a module posttest would get the next module at a higher level. Students learning with this system outperformed those learning with the

  16. Use of ICT and its Relationship with Performance in Examinations: A Comparison of the ImpaCT2 Project's Research Findings Using Pupil-Level, School-Level and Multilevel Modelling Data

    ERIC Educational Resources Information Center

    Harrison, Colin; Lunzer, Eric A.; Tymms, Peter; Fitz-Gibbon, Carol Taylor; Restorick, Jane

    2004-01-01

    This paper reports a previously unpublished comparative analysis of data from the ImpaCT2 study investigating the relationship between students' performance in England on national tests and their reported use of information technology (particularly networked technology) for school work, at three age levels (11, 14 and 16), in English, Maths and…

  17. Innovative Alternatives to Lifting Overturned Military Vehicles

    DTIC Science & Technology

    2014-04-25

    NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS( ES ) United States Air Force Academy,Washington,DC,20301 8...PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS( ES ) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR...Initial testing of the prototype involved using a SATEC load frame to apply a load. As previously stated, during the first test the design failed

  18. Subordinate Perception and Evaluation of Leaders Who Differ on a Personal Characteristic: Are Leaders Interchangeable.

    DTIC Science & Technology

    1982-01-01

    the LBDQ (measures of initiating structure and consideration) and either subsequent performance or satisfaction . Instead, the literature on the...on follower satisfaction and performance . Journal oaf Buins Researc , 1975, .1, 33-42. Bartol, K.M. The sex structuring of organizations: A search for...pencil instruments based on previous work on leadership by Vroom were created. Each story described a leader, the subject’s immediate superior, in a

  19. Analysis and optimization of population annealing

    NASA Astrophysics Data System (ADS)

    Amey, Christopher; Machta, Jonathan

    2018-03-01

    Population annealing is an easily parallelizable sequential Monte Carlo algorithm that is well suited for simulating the equilibrium properties of systems with rough free-energy landscapes. In this work we seek to understand and improve the performance of population annealing. We derive several useful relations between quantities that describe the performance of population annealing and use these relations to suggest methods to optimize the algorithm. These optimization methods were tested by performing large-scale simulations of the three-dimensional (3D) Edwards-Anderson (Ising) spin glass and measuring several observables. The optimization methods were found to substantially decrease the amount of computational work necessary as compared to previously used, unoptimized versions of population annealing. We also obtain more accurate values of several important observables for the 3D Edwards-Anderson model.

  20. Ubiquitous Working: Do Work Versus Non-work Environments Affect Decision-Making and Concentration?

    PubMed

    Burmeister, Carolin P; Moskaliuk, Johannes; Cress, Ulrike

    2018-01-01

    New communication technologies and mobile devices have enabled knowledge workers to work independently of location and in more than one fixed environment (ubiquitous working). Previous research shows that physical environments can influence cognition and work performance. We manipulated environment (i.e., a virtual office as a typical work environment compared to a virtual garden as a non-work environment ) and time pressure (i.e., inducing time pressure vs. no time pressure ) in order to investigate whether the environment influences decision-making and concentration. N = 109 students participated in this laboratory experiment. We posited (a) that a work environment would activate a work-related schema which in turn would enhance concentration performance and make decisions more risky compared to non-work environments and (b) that the environmental effect is more pronounced if time pressure is present compared to conditions where no time pressure is present. We found modest hypothesis-confirming main effects of environment on decision-making and concentration but no interaction effect with time pressure. As we used an innovative methodology that entails several limitations, future research is needed to give insights into the process and to investigate whether results hold true for all types of work settings, work demands, or work activities.

  1. History of concussion impacts electrophysiological correlates of working memory.

    PubMed

    Hudac, Caitlin M; Cortesa, Cathryn S; Ledwidge, Patrick S; Molfese, Dennis L

    2017-10-10

    Sports-related concussions occur in approximately 21% of college athletes with implications for long-term cognitive impairments in working memory. Working memory involves the capacity to maintain short-term information and integrate with higher-order cognitive processing for planning and behavior execution, critical skills for optimal cognitive and athletic performance. This study quantified working memory impairments in 36 American football college athletes (18-23years old) using event-related potentials (ERPs). Despite performing similarly in a standard 2-back working memory task, athletes with history of concussion exhibited larger P1 and P3 amplitudes compared to Controls. Concussion History group latencies were slower for the P1 and faster for the N2. Source estimation analyses indicated that previously concussed athletes engaged different brain regions compared to athletes with no concussion history. These findings suggest that ERPs may be a sensitive and objective measure to detect long-term cognitive consequences of concussion. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Cancer and treatment effects on job task performance for gynecological cancer survivors.

    PubMed

    Nachreiner, Nancy M; Shanley, Ryan; Ghebre, Rahel G

    2013-01-01

    Over 91,000 new cases of gynecological cancers are expected to be diagnosed in 2013 in the US alone. As cancer detection technology and treatment options improve, the number of working-age cancer survivors continues to grow. To describe US gynecological cancer survivors' perceptions of the effects of cancer and treatment on their job tasks. 104 adult gynecological cancer survivors who were working at the time of their cancer diagnosis, treated at a University-based women's health clinic, diagnosed in the previous 24 months, and spoke English. Women completed written surveys to describe their work experiences following diagnosis. Clinical characteristics were obtained through medical record review. Descriptive statistics and cross tabulations were performed to describe characteristics and associations. Fifteen percent of women had chemotherapy and radiation treatment; 48% had only chemotherapy, 9% only radiation therapy, and 28% had neither. Survivors described the frequency of performing seven job tasks, such as 'intense concentration', 'analyzing data', and 'lifting heavy loads.' Women who had undergone radiation treatment were more likely to indicate limitations for physical tasks; women undergoing chemotherapy were more likely to report limitations in more analytic tasks. Only 29% of women noted an employer-based policy facilitated their return-to-work process. Cancer and treatment have important effects on job performance and may vary by type of treatment. Employer-based policies focusing on improved communication and work accommodations may improve the return to work process.

  3. The effect of resting blood flow occlusion on exercise tolerance and W'.

    PubMed

    Broxterman, Ryan M; Craig, Jesse C; Ade, Carl J; Wilcox, Samuel L; Barstow, Thomas J

    2015-09-15

    It has previously been postulated that the anaerobic work capacity (W') may be utilized during resting blood flow occlusion in the absence of mechanical work. We tested the hypothesis that W' would not be utilized during an initial range of time following the onset of resting blood flow occlusion, after which W' would be utilized progressively more. Seven men completed blood flow occlusion constant power severe intensity handgrip exercise to task failure following 0, 300, 600, 900, and 1,200 s of resting blood flow occlusion. The work performed above critical power (CP) was not significantly different between the 0-, 300-, and 600-s conditions and was not significantly different from the total W' available. Significantly less work was performed above CP during the 1,200-s condition than the 900-s condition (P < 0.05), while both conditions were significantly less than the 0-, 300-, and 600-s conditions (P < 0.05). The work performed above CP during these conditions was significantly less than the total W' available (P < 0.05). The utilization of W' during resting blood flow occlusion did not begin until 751 ± 118 s, after which time W' was progressively utilized. The current findings demonstrate that W' is not utilized during the initial ∼751 s of resting blood flow occlusion, but is progressively utilized thereafter, despite no mechanical work being performed. Thus, the utilization of W' is not exclusive to exercise, and a constant amount of work that can be performed above CP is not the determining mechanism of W'. Copyright © 2015 the American Physiological Society.

  4. Bullying among radiation therapists: effects on job performance and work environment.

    PubMed

    Trad, Megan; Johnson, Jordan

    2014-01-01

    To identify the effects of workplace bullying in the radiation therapy department on job performance and explore the environment and morale of individuals who work with a bully. A quantitative research study was designed to assess the prevalence and effects of bullying in the radiation therapy workplace. A total of 308 radiation therapists participated in the study for a return rate of 46%. Of those, 194 indicated that workplace bullying was present either in their current workplace or in a previous radiation therapy environment and that it negatively affected job performance and satisfaction. Findings of this study indicate a need for evaluation of the radiation therapy workplace, education on how to identify and prevent bullying behavior, and better communication among members of the radiation therapy environment. Participants indicated that working in a hostile environment led to forgetfulness, ineffective communication, and perceived discrepancies in promotion and treatment by management. Any bullying behavior contributes to an overall toxic work environment, which is unhealthy and unsafe for patients and therapists. Those who manage therapists should promote a culture of safety and embrace their staff's independence.

  5. Perceived stress, pain and work performance among non-patient working personnel with clinical signs of temporomandibular or neck pain.

    PubMed

    Suvinen, T I; Ahlberg, J; Rantala, M; Nissinen, M; Lindholm, H; Könönen, M; Savolainen, A

    2004-08-01

    The aim of the present study was to assess the associations between different types of perceived stress, pain and work performance among non-patients with clinical signs of muscle pain in the head/neck region. One-fifth (n = 241) of the 1339 media employees who had participated in a previous survey (Ahlberg J. et al., J Psychosom Res 2002; 53: 1077-1081) were randomly selected for standardized clinical examinations. Altogether 49% (n = 118) of these subjects had clinical signs of temporomandibular and/or neck muscle pain and were enrolled in the present study. The mean age of the study sample was 46.9 years (s.d. 6.6) and the female to male distribution 2:1. Of the 118 employees 46.5% reported that the pain problem interfered with their ability to work. Perceived ability to work was not significantly associated with age, gender or work positions. According to logistic regression, reduced work performance was significantly positively associated with continuous pain [odds ratio (OR) 4.38; 95% CI 1.21-15.7], level of perceived pain severity (OR 1.30; 95% CI 1.04-1.63), and health stress (OR 2.08; 95% CI 1.22-3.54). The results of this study indicated an association between specific self-reported stress regarding health and work issues, pain and work performance. From a preventive perspective this indicates a need for increased awareness about these associations on not only individual level but also at the organizational level and in health care. Copyright 2004 Blackwell Publishing Ltd.

  6. Estradiol concentrations and working memory performance in women of reproductive age.

    PubMed

    Hampson, Elizabeth; Morley, Erin E

    2013-12-01

    Estrogen has been proposed to exert a regulatory influence on the working memory system via actions in the female prefrontal cortex. Tests of this hypothesis have been limited almost exclusively to postmenopausal women and pharmacological interventions. We explored whether estradiol discernibly influences working memory within the natural range of variation in concentrations characteristic of the menstrual cycle. The performance of healthy women (n=39) not using hormonal contraceptives, and a control group of age- and education-matched men (n=31), was compared on a spatial working memory task. Cognitive testing was done blind to ovarian status. Women were retrospectively classified into low- or high-estradiol groups based on the results of radioimmunoassays of saliva collected immediately before and after the cognitive testing. Women with higher levels of circulating estradiol made significantly fewer errors on the working memory task than women tested under low estradiol. Pearson's correlations showed that the level of salivary estradiol but not progesterone was correlated inversely with the number of working memory errors produced. Women tested at high levels of circulating estradiol tended to be more accurate than men. Superior performance by the high estradiol group was seen on the working memory task but not on two control tasks, indicating selectivity of the effects. Consistent with previous studies of postmenopausal women, higher levels of circulating estradiol were associated with better working memory performance. These results add further support to the hypothesis that the working memory system is modulated by estradiol in women, and show that the effects can be observed under non-pharmacological conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Cognitive control components and speech symptoms in people with schizophrenia.

    PubMed

    Becker, Theresa M; Cicero, David C; Cowan, Nelson; Kerns, John G

    2012-03-30

    Previous schizophrenia research suggests poor cognitive control is associated with schizophrenia speech symptoms. However, cognitive control is a broad construct. Two important cognitive control components are poor goal maintenance and poor verbal working memory storage. In the current research, people with schizophrenia (n=45) performed three cognitive tasks that varied in their goal maintenance and verbal working memory storage demands. Speech symptoms were assessed using clinical rating scales, ratings of disorganized speech from typed transcripts, and self-reported disorganization. Overall, alogia was associated with both goal maintenance and verbal working memory tasks. Objectively rated disorganized speech was associated with poor goal maintenance and with a task that included both goal maintenance and verbal working memory storage demands. In contrast, self-reported disorganization was unrelated to either amount of objectively rated disorganized speech or to cognitive control task performance, instead being associated with negative mood symptoms. Overall, our results suggest that alogia is associated with both poor goal maintenance and poor verbal working memory storage and that disorganized speech is associated with poor goal maintenance. In addition, patients' own assessment of their disorganization is related to negative mood, but perhaps not to objective disorganized speech or to cognitive control task performance. Published by Elsevier Ireland Ltd.

  8. Electrochemical characterization of nanodimensional metal oxide materials

    NASA Astrophysics Data System (ADS)

    Tang, Paul Enle

    Energy storage devices have become a bottleneck in performance improvements for portable electronics. This research seeks to answer basic science questions that may lead to the necessary improvements. First, this work demonstrates that insertion of multivalent ions into vanadium oxide greatly exceeds the storage capacity of materials presently used. Second, this work demonstrates that potassium ferrate exhibits a uniquely large pseudocapacitive effect. This effect can be used to great advantage when high power density and high energy density are required. Lastly, this work proposes a model of pseudocapacitance that has a greater descriptive power than that of previous models.

  9. A comprehensive method for preliminary design optimization of axial gas turbine stages. II - Code verification

    NASA Technical Reports Server (NTRS)

    Jenkins, R. M.

    1983-01-01

    The present effort represents an extension of previous work wherein a calculation model for performing rapid pitchline optimization of axial gas turbine geometry, including blade profiles, is developed. The model requires no specification of geometric constraints. Output includes aerodynamic performance (adiabatic efficiency), hub-tip flow-path geometry, blade chords, and estimates of blade shape. Presented herein is a verification of the aerodynamic performance portion of the model, whereby detailed turbine test-rig data, including rig geometry, is input to the model to determine whether tested performance can be predicted. An array of seven (7) NASA single-stage axial gas turbine configurations is investigated, ranging in size from 0.6 kg/s to 63.8 kg/s mass flow and in specific work output from 153 J/g to 558 J/g at design (hot) conditions; stage loading factor ranges from 1.15 to 4.66.

  10. A swallowtail catastrophe model for the emergence of leadership in coordination-intensive groups.

    PubMed

    Guastello, Stephen J; Bond, Robert W

    2007-04-01

    This research extended the previous studies concerning the swallowtail catastrophe model for leadership emergence to coordination-intensive groups. Thirteen 4-person groups composed of undergraduates played in Intersection coordination (card game) task and were allowed to talk while performing it; 13 other groups worked nonverbally. A questionnaire measured leadership emergence at the end of the game along with other social contributions to the groups' efforts. The swallowtail catastrophe model that was evident in previous leadership emergence phenomena in creative problem solving and production groups was found here also. All three control parameters were identified: a general participation variable that was akin to K in the rugged landscape model of self-organization, task control, and whether the groups worked verbally or nonverbally. Several new avenues for future research were delineated.

  11. Building America Industrialized Housing Partnership (BAIHP II)

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

    Abernethy, Bob; Chandra, Subrato; Baden, Steven

    2010-11-30

    This report summarizes the work conducted by the Building America Industrialized Housing Partnership (BAIHP - www.baihp.org) during the final budget period (BP5) of our contract, January 1, 2010 to November 30, 2010. Highlights from the four previous budget periods are included for context. BAIHP is led by the Florida Solar Energy Center (FSEC) of the University of Central Florida. With over 50 Industry Partners including factory and site builders, work in BP5 was performed in six tasks areas: Building America System Research Management, Documentation and Technical Support; System Performance Evaluations; Prototype House Evaluations; Initial Community Scale Evaluations; Project Closeout, Finalmore » Review of BA Communities; and Other Research Activities.« less

  12. Blood Alcohol Concentration-Related Lower Performance in Immediate Visual Memory and Working Memory in Adolescent Binge Drinkers

    PubMed Central

    Vinader-Caerols, Concepción; Duque, Aránzazu; Montañés, Adriana; Monleón, Santiago

    2017-01-01

    The binge drinking (BD) pattern of alcohol consumption is prevalent during adolescence, a period characterized by critical changes to the structural and functional development of brain areas related with memory and cognition. There is considerable evidence of the cognitive dysfunctions caused by the neurotoxic effects of BD in the not-yet-adult brain. Thus, the aim of the present study was to evaluate the effects of different blood alcohol concentrations (BAC) on memory during late adolescence (18–19 years old) in males and females with a history of BD. The sample consisted of 154 adolescents (67 males and 87 females) that were classified as refrainers if they had never previously drunk alcoholic drinks and as binge drinkers if they had drunk six or more standard drink units in a row for men or five or more for women at a minimum frequency of three occasions in a month, throughout the previous 12 months. After intake of a high acute dose of alcohol by binge drinkers or a control refreshment by refrainers and binge drinkers, subjects were distributed into four groups for each gender according to their BAC: BAC0-R (0 g/L, in refrainers), BAC0-BD (0 g/L, in binge drinkers), BAC1 (0.3 – 0.5 g/L, in binge drinkers) or BAC2 (0.54 – 1.1 g/L, in binge drinkers). The subjects’ immediate visual memory and working memory were then measured according to the Wechsler Memory Scale (WMS-III). The BAC1 group showed lower scores of immediate visual memory but not of working memory, while lower performance in both memories were found in the BAC2 group. Therefore, the brain of binge drinkers with moderate BAC could be employing compensatory mechanisms from additional brain areas to perform a working memory task adequately, but these resources would be undermined when BAC is higher (>0.5 g/L). No gender differences were found in BAC-related lower performance in immediate visual memory and working memory. In conclusion, immediate visual memory is more sensitive than working memory to the neurotoxic effects of alcohol in adolescent binge drinkers of both genders, being a BAC-related lower performance, and without obvious differences between males and females. PMID:29046656

  13. Blood Alcohol Concentration-Related Lower Performance in Immediate Visual Memory and Working Memory in Adolescent Binge Drinkers.

    PubMed

    Vinader-Caerols, Concepción; Duque, Aránzazu; Montañés, Adriana; Monleón, Santiago

    2017-01-01

    The binge drinking (BD) pattern of alcohol consumption is prevalent during adolescence, a period characterized by critical changes to the structural and functional development of brain areas related with memory and cognition. There is considerable evidence of the cognitive dysfunctions caused by the neurotoxic effects of BD in the not-yet-adult brain. Thus, the aim of the present study was to evaluate the effects of different blood alcohol concentrations (BAC) on memory during late adolescence (18-19 years old) in males and females with a history of BD. The sample consisted of 154 adolescents (67 males and 87 females) that were classified as refrainers if they had never previously drunk alcoholic drinks and as binge drinkers if they had drunk six or more standard drink units in a row for men or five or more for women at a minimum frequency of three occasions in a month, throughout the previous 12 months. After intake of a high acute dose of alcohol by binge drinkers or a control refreshment by refrainers and binge drinkers, subjects were distributed into four groups for each gender according to their BAC: BAC0-R (0 g/L, in refrainers), BAC0-BD (0 g/L, in binge drinkers), BAC1 (0.3 - 0.5 g/L, in binge drinkers) or BAC2 (0.54 - 1.1 g/L, in binge drinkers). The subjects' immediate visual memory and working memory were then measured according to the Wechsler Memory Scale (WMS-III). The BAC1 group showed lower scores of immediate visual memory but not of working memory, while lower performance in both memories were found in the BAC2 group. Therefore, the brain of binge drinkers with moderate BAC could be employing compensatory mechanisms from additional brain areas to perform a working memory task adequately, but these resources would be undermined when BAC is higher (>0.5 g/L). No gender differences were found in BAC-related lower performance in immediate visual memory and working memory. In conclusion, immediate visual memory is more sensitive than working memory to the neurotoxic effects of alcohol in adolescent binge drinkers of both genders, being a BAC-related lower performance, and without obvious differences between males and females.

  14. Effect of Polymer Electrode Morphology on Performance of a Lithium/Polypyrrole Battery. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Nicholson, Marjorie Anne

    1991-01-01

    A variety of conducting polymer batteries were described in the recent literature. In this work, a Li/Polypyrrole secondary battery is described. The effect of controlling the morphology of the polymer on enhancement of counterion diffusion in the polymer phase is explored. A method of preparing conducting polymers was developed which yields high surface area per unit volume of electrode material. A porous membrane is used as a template in which to electrochemically polymerize pyrrole, then the membrane is dissolved, leaving the polymer in a fibrillar form. Conventionally, the polymer is electrochemically polymerized as a dense polymer film on a smooth Pt disk electrode. Previous work has shown that when the polymer is electrochemically polymerized in fribrillar form, charge transport rates are faster and charge capacities are greater than for dense, conventionally grown films containing the same amount of polymer. The purpose is to expand previous work by further investigating the possibilities of the optimization of transport rates in polypyrrole films by controlling the morphology of the films. The utility of fibrillar polypyrrole as a cathode material in a lithium/polymer secondary battery is then assessed. The performance of the fibrillar battery is compared to the performance of an analogous battery which employed a conventionally grown polypyrrole film. The study includes a comparison of cyclic voltammetry, shape of charge/discharge curves, discharge time and voltage, cycle life, coulombic efficiencies, charge capacities, energy densities, and energy efficiencies.

  15. A functional promoter variant of the human formimidoyltransferase cyclodeaminase (FTCD) gene is associated with working memory performance in young but not older adults.

    PubMed

    Greenwood, Pamela M; Schmidt, Kevin; Lin, Ming-Kuan; Lipsky, Robert; Parasuraman, Raja; Jankord, Ryan

    2018-06-21

    The central role of working memory in IQ and the high heritability of working memory performance motivated interest in identifying the specific genes underlying this heritability. The FTCD (formimidoyltransferase cyclodeaminase) gene was identified as a candidate gene for allelic association with working memory in part from genetic mapping studies of mouse Morris water maze performance. The present study tested variants of this gene for effects on a delayed match-to-sample task of a large sample of younger and older participants. The rs914246 variant, but not the rs914245 variant, of the FTCD gene modulated accuracy in the task for younger, but not older, people under high working memory load. The interaction of haplotype × distance × load had a partial eta squared effect size of 0.015. Analysis of simple main effects had partial eta squared effect sizes ranging from 0.012 to 0.040. A reporter gene assay revealed that the C allele of the rs914246 genotype is functional and a main factor regulating FTCD gene expression. This study extends previous work on the genetics of working memory by revealing that a gene in the glutamatergic pathway modulates working memory in young people but not in older people. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  16. Neuromotor function in ship welders after cessation of manganese exposure.

    PubMed

    Wastensson, Gunilla; Sallsten, Gerd; Bast-Pettersen, Rita; Barregard, Lars

    2012-08-01

    The aim of the present study was to investigate whether previous long-term exposure to manganese (Mn) via inhalation of welding fumes can cause persistent impairment in neuromotor function even long after cessation of exposure. Quantitative tests of tremor, motor speed, manual dexterity, diadochokinesis, eye-hand coordination and postural stability were administered to 17 retired ship welders (mean age 69 years), with mean exposure time 28 years. The welders' exposure had ceased on average 18 years before the study. A cumulative exposure index (CEI) was calculated for each of the former welders. The welders were compared with 21 referents from the same shipyards (mean age was 66 years). Former welders performed less well than referents in the grooved pegboard test, and poorer performance was associated with CEI. The performance in most of the other neurobehavioral tests was similar between groups, but the welders tended to perform slightly better than the referents in tests demanding hand steadiness. The latter finding may be due to a training effect from their former working tasks or selection bias into or out of this occupation. In the present study of welders with previous welding fume exposure, former welders and referents performed similarly in most of the neurobehavioral tests. Previous adverse effects on the neuromotor system might have ceased, and decreased neuromotor function due to normal aging processes in both groups might have disguised any slight effect of previous Mn exposure. The poorer performance in the grooved pegboard test among welders may indicate an adverse effect on motor function of long-term exposure to Mn, but this finding has to be confirmed by other studies.

  17. Development and Validation of Rapid In Situ Assays of Environmental Mutagenesis

    DTIC Science & Technology

    1990-10-31

    has also been suggested (12). Previous work has indicated that wild rodents can be effectively used as insit genetic biomonitors. McBee et al. (13...NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) Oklahoma State Universi ty AEOS~- ~ _ 0 6a. NAME OF PERFORMING ORGANIZATION r6b. OFFICE SYMBOL 7a...ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS Building 410 PROGRAM PROJECT TASK WORK UNIT Bolling AFB DC .20332/6448 ELEMENT NO. INO

  18. Determination of the Secondary Bjerknes Force in Acoustic Resonators on Ground and in Microgravity Conditions

    NASA Astrophysics Data System (ADS)

    Castro, Luz Angelica; Hoyos, Mauricio

    2016-04-01

    We propose an experimental methodology to determine the secondary Bjerknes force between rigid particles. Measurements done for different particles sizes showed acoustical inter particles interactions. We use and extend the methodology presented in a previous work. The determination of this force will lead us a better understanding of the aggregation process in acoustic resonators. We report in this work, the results of two parabolic flights campaigns performed at the Airbus A300 ZERO-G (Novespace, France).

  19. Testing and Characterization of a Prototype Telescope for the Evolved Laser Interferometer Space Antenna (eLISA)

    NASA Technical Reports Server (NTRS)

    Sankar, S.; Livas, J.

    2016-01-01

    We describe our efforts to fabricate, test and characterize a prototype telescope for the eLISA mission. Much of our work has centered on the modeling and measurement of scattered light performance. This work also builds on a previous demonstration of a high dimensional stability metering structure using particular choices of materials and interfaces. We will discuss ongoing plans to merge these two separate demonstrations into a single telescope design demonstrating both stray light and dimensional stability requirements simultaneously.

  20. Surgical simulation tasks challenge visual working memory and visual-spatial ability differently.

    PubMed

    Schlickum, Marcus; Hedman, Leif; Enochsson, Lars; Henningsohn, Lars; Kjellin, Ann; Felländer-Tsai, Li

    2011-04-01

    New strategies for selection and training of physicians are emerging. Previous studies have demonstrated a correlation between visual-spatial ability and visual working memory with surgical simulator performance. The aim of this study was to perform a detailed analysis on how these abilities are associated with metrics in simulator performance with different task content. The hypothesis is that the importance of visual-spatial ability and visual working memory varies with different task contents. Twenty-five medical students participated in the study that involved testing visual-spatial ability using the MRT-A test and visual working memory using the RoboMemo computer program. Subjects were also trained and tested for performance in three different surgical simulators. The scores from the psychometric tests and the performance metrics were then correlated using multivariate analysis. MRT-A score correlated significantly with the performance metrics Efficiency of screening (p = 0.006) and Total time (p = 0.01) in the GI Mentor II task and Total score (p = 0.02) in the MIST-VR simulator task. In the Uro Mentor task, both the MRT-A score and the visual working memory 3-D cube test score as presented in the RoboMemo program (p = 0.02) correlated with Total score (p = 0.004). In this study we have shown that some differences exist regarding the impact of visual abilities and task content on simulator performance. When designing future cognitive training programs and testing regimes, one might have to consider that the design must be adjusted in accordance with the specific surgical task to be trained in mind.

  1. MHD work related to a self-cooled Pb-17Li blanket with poloidal-radial-toroidal ducts

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

    Reimann, J.; Barleon, L.; Buehler, L.

    1994-12-31

    For self cooled liquid metal blankets MHD pressure drop and velocity distributions are considered as critical issues. This paper summarizes MHD work performed for a DEMO-relevant Pb-17Li blanket which uses essential characteristics of a previous ANL design: The coolant flows downwards in the rear poloidal ducts, turns by 180{degrees} at the blanket bottom and is distributed from the ascending poloidal ducts into short radial channels which feed the toroidal First Wall coolant ducts (aligned with the main magnetic field direction). The flow through the subsequent radial channels is collected again in poloidal channels and the coolant leaves the blanket segmentmore » at the top. The blanket design is based on the use of flow channel inserts (FCIs) (which means electrically thin conducting walls for MHD) for all ducts except for the toroidal FW coolant channels. MHD related issues were defined and estimations of corresponding pressure drops were performed. Previous experimental work included a proof of principle of FCIs and a detailed experiment with a single {open_quotes}poloidal{sm_bullet}toroidal{sm_bullet}poloidal{close_quotes} duct (cooperation with ANL). In parallel, a numerical code based on the Core Flow Approximation (CFA) was developed to predict pressure drop and velocity distributions for arbitrary single duct geometries.« less

  2. Performance tests of a two phase ejector

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

    Harrell, G.S.; Kornhauser, A.A.

    1995-12-31

    The ejector expansion refrigeration cycle is a modified vapor compression cycle in which a two phase ejector is used to recover a portion of the work otherwise lost in the expansion valve. The ejector improves cycle performance by increasing compressor inlet pressure and by lowering the quality of liquid entering the evaporator. Theoretically, a cooling COP improvement of approximately 23% is achievable for a typical refrigerating cycle and an ideal ejector. If the ejector performed as well as typical single phase ejectors an improvement of 12% could be achieved. Previous tests have demonstrated a smaller 3.7% improvement; the difference ismore » in the poor performance of the two phase ejector. The purpose of this research is to understand the operating characteristics of the two phase ejector and to devise design improvements. A two phase ejector test rig has been constructed and tested. Preliminary data show performance superior to previously tested two phase ejectors, but still inferior to single phase ejectors. Ejector performance corresponds to refrigeration cycle COP improvements ranging from 3.9% to 7.6%.« less

  3. Family to work conflict and the usefulness of workplace support.

    PubMed

    Hancock, F; Page, F

    2013-07-01

    While much is known about the effect of work stress on an employee's home life, less is known about the opposite effect, that of domestic worries upon work performance. To investigate employee perceptions about the effect of family to work conflict (FWC) on work. An online anonymous survey tool was developed and sent to all employees reporting to a single onsite human resources (HR) department at a UK research and development plant. FWC included family and other domestic stressors. Work effects studied included those on business travel, work performance and the awareness and usefulness of work-provided support. The sample size was 286 and response rate was 58%. Approximately two-thirds of respondents reported requiring time away from work for domestic reasons in the previous 5 years. The role of domestic stressors not related to care giving was significant. Support from line-managers and colleagues was important, and the perceived usefulness of in-house occupational health (OH) by business travellers was significant. Only 53% of the workforce said they knew of the Employee Assistance Programme (EAP), although 70% of users found it beneficial and usage was higher in females. All forms of FWC affected work performance, including when on business travel. FWC arose from caring responsibilities but also from financial and relationship problems, which are potentially amenable to help from EAPs. Line-managers and colleagues were the primary sources of workplace support. The in-house OH service and the EAP were underutilized and they may require popularizing with employees.

  4. Effects of cognitive appraisal and mental workload factors on performance in an arithmetic task.

    PubMed

    Galy, Edith; Mélan, Claudine

    2015-12-01

    We showed in a previous study an additive interaction between intrinsic and extraneous cognitive loads and of participants' alertness in an 1-back working memory task. The interaction between intrinsic and extraneous cognitive loads was only observed when participants' alertness was low (i.e. in the morning). As alertness is known to reflect an individual's general functional state, we suggested that the working memory capacity available for germane cognitive load depends on a participant's functional state, in addition to intrinsic and extraneous loads induced by the task and task conditions. The relationships between the different load types and their assessment by specific load measures gave rise to a modified cognitive load model. The aim of the present study was to complete the model by determining to what extent and at what processing level an individual's characteristics intervene in order to implement efficient strategies in a working memory task. Therefore, the study explored participants' cognitive appraisal of the situation in addition to the load factors considered previously-task difficulty, time pressure and alertness. Each participant performed a mental arithmetic task in four different cognitive load conditions (crossover of two task difficulty conditions and of two time pressure conditions), both while their alertness was low (9 a.m.) and high (4 p.m.). Results confirmed an additive effect of task difficulty and time pressure, previously reported in the 1-back memory task, thereby lending further support to the modified cognitive load model. Further, in the high intrinsic and extraneous load condition, performance was reduced on the morning session (i.e. when alertness was low) on one hand, and in those participants' having a threat appraisal of the situation on the other hand. When these factors were included into the analysis, a performance drop occurred in the morning irrespective of cognitive appraisal, and with threat appraisal in the afternoon (i.e. high alertness). Taken together, these findings indicate that mental overload can be the result of a combination of subject-related characteristics, including alertness and cognitive appraisal, in addition to well-documented task-related components (intrinsic and extraneous load). As the factors investigated in the study are known to be critically involved in a number of real job-activities, the findings suggest that solutions designed to reduce incidents and accidents at work should consider the situation from a global perspective, including individual characteristics, task parameters, and work organization, rather than dealing with each factor separately.

  5. The association between loss of work ability and depression: a focus on employment status.

    PubMed

    Lee, Sang Ah; Ju, Yeong Jun; Han, Kyu-Tae; Choi, Jae Woo; Yoon, Hyo Jung; Park, Eun-Cheol

    2017-01-01

    Work-related factors are one of the known risk factors for depression. Given that the ability to work is considered an important aspect of well-being and health status, we investigated the association between the loss of work ability and depression. We further examined the association stratified by employment status. We used data from the Korea Welfare Panel Study. The dependent variable of the present study was depression, which is measured by the Center for Epidemiologic Studies Depression Scale. Work ability transition from the previous year was divided into three categories: maintained, loss, and complete loss. A linear mixed-effects model was performed for the analysis. The work ability loss group (β = 2.071, p < 0.0002) and the work ability completely loss group (β = 2.651, p = 0.015) had higher depression scores compared to those who maintained their work ability from the previous year. Specifically, those who lost their work ability and their job (β = 3.685, p = 0.0068) had the highest depression scores compared to those who maintained their work ability and job. We found that those who lost their ability to work may be at risk of depression, and this finding was particularly prominent among those who also became unemployed. Therefore, psychological support is needed for these individuals to overcome the negative influence of the loss of work ability.

  6. Effect of retinal defocus on basketball free throw shooting performance.

    PubMed

    Bulson, Ryan C; Ciuffreda, Kenneth J; Hayes, John; Ludlam, Diana P

    2015-07-01

    Vision plays a critical role in athletic performance; however, previous studies have demonstrated that a variety of simulated athletic sensorimotor tasks can be surprisingly resilient to retinal defocus (blurred vision). The purpose of the present study was to extend this work to determine the effect of retinal defocus on overall basketball free throw performance, as well as for the factors gender, refractive error and experience. Forty-four young adult participants of both genders were recruited. They had a range of refractive errors and basketball experience. Each performed 20 standard basketball free throws under five lens defocus conditions in a randomised manner: plano, +1.50 D, +3.00 D, +4.50 D and +10.00 D. Overall, free throw performance was significantly reduced under the +10.00 D lens defocus condition only. Previous experience, but neither refractive error nor gender, yielded a statistically significant difference in performance. Consistent with previous studies of complex sensorimotor tasks, basketball free throw performance was resilient to low and moderate levels of retinal defocus. Thus, for a relatively non-dynamic motor task at a fixed far distance, such as the basketball free throw, precise visual clarity was not critical. Other factors such as motor memory may be important. However, in the dynamic athletic competitive environment it is likely that visual clarity plays a more critical role in one's performance level, at least for specific task demands. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  7. Performance Analysis: Work Control Events Identified January - August 2010

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

    De Grange, C E; Freeman, J W; Kerr, C E

    2011-01-14

    This performance analysis evaluated 24 events that occurred at LLNL from January through August 2010. The analysis identified areas of potential work control process and/or implementation weaknesses and several common underlying causes. Human performance improvement and safety culture factors were part of the causal analysis of each event and were analyzed. The collective significance of all events in 2010, as measured by the occurrence reporting significance category and by the proportion of events that have been reported to the DOE ORPS under the ''management concerns'' reporting criteria, does not appear to have increased in 2010. The frequency of reporting inmore » each of the significance categories has not changed in 2010 compared to the previous four years. There is no change indicating a trend in the significance category and there has been no increase in the proportion of occurrences reported in the higher significance category. Also, the frequency of events, 42 events reported through August 2010, is not greater than in previous years and is below the average of 63 occurrences per year at LLNL since 2006. Over the previous four years, an average of 43% of the LLNL's reported occurrences have been reported as either ''management concerns'' or ''near misses.'' In 2010, 29% of the occurrences have been reported as ''management concerns'' or ''near misses.'' This rate indicates that LLNL is now reporting fewer ''management concern'' and ''near miss'' occurrences compared to the previous four years. From 2008 to the present, LLNL senior management has undertaken a series of initiatives to strengthen the work planning and control system with the primary objective to improve worker safety. In 2008, the LLNL Deputy Director established the Work Control Integrated Project Team to develop the core requirements and graded elements of an institutional work planning and control system. By the end of that year this system was documented and implementation had begun. In 2009, training of the workforce began and as of the time of this report more than 50% of authorized Integration Work Sheets (IWS) use the activity-based planning process. In 2010, LSO independently reviewed the work planning and control process and confirmed to the Laboratory that the Integrated Safety Management (ISM) System was implemented. LLNL conducted a cross-directorate management self-assessment of work planning and control and is developing actions to respond to the issues identified. Ongoing efforts to strengthen the work planning and control process and to improve the quality of LLNL work packages are in progress: completion of remaining actions in response to the 2009 DOE Office of Health, Safety, and Security (HSS) evaluation of LLNL's ISM System; scheduling more than 14 work planning and control self-assessments in FY11; continuing to align subcontractor work control with the Institutional work planning and control system; and continuing to maintain the electronic IWS application. The 24 events included in this analysis were caused by errors in the first four of the five ISMS functions. The most frequent cause was errors in analyzing the hazards (Function 2). The second most frequent cause was errors occurring when defining the work (Function 1), followed by errors during the performance of work (Function 4). Interestingly, very few errors in developing controls (Function 3) resulted in events. This leads one to conclude that if improvements are made to defining the scope of work and analyzing the potential hazards, LLNL may reduce the frequency or severity of events. Analysis of the 24 events resulted in the identification of ten common causes. Some events had multiple causes, resulting in the mention of 39 causes being identified for the 24 events. The most frequent cause was workers, supervisors, or experts believing they understood the work and the hazards but their understanding was incomplete. The second most frequent cause was unclear, incomplete or confusing documents directing the work. Together, these two causes were mentioned 17 times and contributed to 13 of the events. All of the events with the cause of ''workers, supervisors, or experts believing they understood the work and the hazards but their understanding was incomplete'' had this error in the first two ISMS functions: define the work and analyze the hazard. This means that these causes result in the scope of work being ill-defined or the hazard(s) improperly analyzed. Incomplete implementation of these functional steps leads to the hazards not being controlled. The causes are then manifested in events when the work is conducted. The process to operate safely relies on accurately defining the scope of work. This review has identified a number of examples of latent organizational weakness in the execution of work control processes.« less

  8. The Association between Meditation Practice and Job Performance: A Cross-Sectional Study

    PubMed Central

    Sugimoto, Minami; Ishikawa, Yoshiki

    2015-01-01

    Many previous studies have shown that meditation practice has a positive impact on cognitive and non-cognitive functioning, which are related to job performance. Thus, the aims of this study were to (1) estimate the prevalence of meditation practice, (2) identify the characteristics of individuals who practice meditation, and (3) examine the association between meditation practice and job performance. Two population-based, cross-sectional surveys were conducted. In study 1, we examined the prevalence of meditation practice and the characteristics of the persons practicing meditation; in Study 2, we examined the association between meditation practice and job performance. The outcome variables included work engagement, subjective job performance, and job satisfaction. The Utrecht Work Engagement Scale was used to assess work engagement, the World Health Organization Health and Work Performance Questionnaire (HPQ) was used to measure subjective job performance, and a scale developed by the Japanese government was used to assess job satisfaction. Hierarchical multiple regression analyses were used in Study 2. Demographic characteristics and behavioral risk factors were included as covariates in the analyses. The results of Study 1 indicated that 3.9% of persons surveyed (n = 30,665) practiced meditation; these individuals were younger and had a higher education, higher household income, higher stress level, and lower body mass index than those who did not practice meditation. The results of Study 2 (n = 1,470) indicated that meditation practice was significantly predictive of work engagement (β = 0.112, p < .001), subjective job performance (β = 0.116, p < .001), and job satisfaction (β = 0.079, p = .002), even after adjusting for covariates (β = 0.083, p < .001; β = 0.104, p < .001; β = 0.060, p = .015, respectively). The results indicate that meditation practice may positively influence job performance, including job satisfaction, subjective job performance, and work engagement. PMID:26024382

  9. Analogue prototypes for Lunar and Mars exploration.

    PubMed

    Stuster, Jack

    2005-06-01

    Small groups living and working in isolation and confinement experience unique stressors that have predictable effects on individual adjustment and performance. Because the stress is cumulative, long-duration missions impose considerable burdens on an individual's capacity to adjust to the conditions and to perform well, both technically and socially. This paper describes research conducted to extrapolate design and procedural guidelines for lunar and planetary expeditions from a review of information concerning previous expeditions and voyages of discovery.

  10. Toward a Superior Promotion System

    DTIC Science & Technology

    2012-08-01

    AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Air Force Research Institute (AFRI...Air & Space Power Journal,155 N Twining Street,Maxwell AFB,AL,36112 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME...this lan­ guage might have arisen to remedy a problem in this or previous evalua­ tion systems and has continued to exist as a vestigial feature. The

  11. A new algorithm for reducing the workload of experts in performing systematic reviews.

    PubMed

    Matwin, Stan; Kouznetsov, Alexandre; Inkpen, Diana; Frunza, Oana; O'Blenis, Peter

    2010-01-01

    To determine whether a factorized version of the complement naïve Bayes (FCNB) classifier can reduce the time spent by experts reviewing journal articles for inclusion in systematic reviews of drug class efficacy for disease treatment. The proposed classifier was evaluated on a test collection built from 15 systematic drug class reviews used in previous work. The FCNB classifier was constructed to classify each article as containing high-quality, drug class-specific evidence or not. Weight engineering (WE) techniques were added to reduce underestimation for Medical Subject Headings (MeSH)-based and Publication Type (PubType)-based features. Cross-validation experiments were performed to evaluate the classifier's parameters and performance. Work saved over sampling (WSS) at no less than a 95% recall was used as the main measure of performance. The minimum workload reduction for a systematic review for one topic, achieved with a FCNB/WE classifier, was 8.5%; the maximum was 62.2% and the average over the 15 topics was 33.5%. This is 15.0% higher than the average workload reduction obtained using a voting perceptron-based automated citation classification system. The FCNB/WE classifier is simple, easy to implement, and produces significantly better results in reducing the workload than previously achieved. The results support it being a useful algorithm for machine-learning-based automation of systematic reviews of drug class efficacy for disease treatment.

  12. The role of attention in item-item binding in visual working memory.

    PubMed

    Peterson, Dwight J; Naveh-Benjamin, Moshe

    2017-09-01

    An important yet unresolved question regarding visual working memory (VWM) relates to whether or not binding processes within VWM require additional attentional resources compared with processing solely the individual components comprising these bindings. Previous findings indicate that binding of surface features (e.g., colored shapes) within VWM is not demanding of resources beyond what is required for single features. However, it is possible that other types of binding, such as the binding of complex, distinct items (e.g., faces and scenes), in VWM may require additional resources. In 3 experiments, we examined VWM item-item binding performance under no load, articulatory suppression, and backward counting using a modified change detection task. Binding performance declined to a greater extent than single-item performance under higher compared with lower levels of concurrent load. The findings from each of these experiments indicate that processing item-item bindings within VWM requires a greater amount of attentional resources compared with single items. These findings also highlight an important distinction between the role of attention in item-item binding within VWM and previous studies of long-term memory (LTM) where declines in single-item and binding test performance are similar under divided attention. The current findings provide novel evidence that the specific type of binding is an important determining factor regarding whether or not VWM binding processes require attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. Transitions in Learning: Evidence for Simultaneously Activated Strategies.

    ERIC Educational Resources Information Center

    Goldin-Meadow, Susan; And Others

    Children rarely cite more than one strategy when asked to explain how they solved a particular arithmetic problem, hence their verbal explanations will not necessarily reveal whether they have considered multiple strategies on that problem. However, previous work has shown that, when asked to explain their performance on a task, children often use…

  14. Application of Multiple Index Development Approaches to Benthic Invertebrate Data from the Virginian Biogeographic Province, USA

    EPA Science Inventory

    Previous work had indicated that the Virginian Province Index did not perform well in a smaller estuarine complex. While it was hoped that the existing Chesapeake Bay Benthic Index of Biotic Integrity, with its greater number of metrics and habitat separation would be more adapt...

  15. Epistemic Match: A Pedagogical Concept for Understanding How Students Fit into the Chosen Subject

    ERIC Educational Resources Information Center

    O'Siochru, Cathal; Norton, Lin

    2014-01-01

    Previous studies have suggested that a student's personal epistemological beliefs can be a predictor of their academic performance. The current research aimed to extend this work by exploring whether the disciplinary epistemological beliefs presented to students in their classes and assessments might mediate the relationship between students'…

  16. Expertise-Based Differences in Search and Option-Generation Strategies

    ERIC Educational Resources Information Center

    Raab, Markus; Johnson, Joseph G.

    2007-01-01

    The current work builds on option-generation research using experts of various skill levels in a realistic task. We extend previous findings that relate an athlete's performance strategy to generated options and subsequent choices in handball. In a 2-year longitudinal study, we present eye-tracking data to independently verify decision strategies…

  17. Improving Learners' Oral Fuency through Computer-Mediated Emotional Intelligence Activities

    ERIC Educational Resources Information Center

    Abdolrezapour, Parisa

    2017-01-01

    Previous studies have shown that emotional intelligence (henceforth, EI) has a significant impact on important life outcomes (e.g., mental and physical health, academic achievement, work performance, and social relationships). This study aimed to see whether there is any relationship between EI and English as a foreign language (EFL) learners'…

  18. "From England with Love"… ARK, Heterarchies and Global "Philanthropic Governance"

    ERIC Educational Resources Information Center

    Olmedo, Antonio

    2014-01-01

    The recent emergence of "new" venture philanthropists, social entrepreneurs and neoliberal policy advocates and the new ways in which they configure and perform their political agendas have brought important changes in the way in which education policy is enacted. This study takes some of the ideas sketched in previous work further and…

  19. Exploring Differential Bundle Functioning in Mathematics by Gender: The Effect of Hierarchical Modelling

    ERIC Educational Resources Information Center

    Ong, Yoke Mooi; Williams, Julian; Lamprianou, Iasonas

    2013-01-01

    Researchers interested in exploring substantive group differences are increasingly attending to bundles of items (or testlets): the aim is to understand how gender differences, for instance, are explained by differential performances on different types or bundles of items, hence differential bundle functioning (DBF). Some previous work has…

  20. Exploring performance obstacles of intensive care nurses.

    PubMed

    Gurses, Ayse P; Carayon, Pascale

    2009-05-01

    High nursing workload, poor patient safety, and poor nursing quality of working life (QWL) are major issues in intensive care units (ICUs). Characteristics of the ICU and performance obstacles may contribute to these issues. The goal of this study was to comprehensively identify the performance obstacles perceived by ICU nurses. We used a qualitative research design and conducted semi-structured interviews with 15 ICU nurses of a medical-surgical ICU. Based on this qualitative study and a previously reported quantitative study, we identified seven main types of performance obstacles experienced by ICU nurses. Obstacles related to the physical environment (e.g., noise, amount of space), family relations (e.g., distractions caused by family, lack of time to spend with family), and equipment (e.g., unavailability, misplacement) were the most frequently experienced performance obstacles. The qualitative interview data provided rich information regarding the factors contributing to the performance obstacles. Overall, ICU nurses experience a variety of performance obstacles in their work on a daily basis. Future research is needed to understand the impact of performance obstacles on nursing workload, nursing QWL, and quality and safety of care.

  1. Improved image guidance technique for minimally invasive mitral valve repair using real-time tracked 3D ultrasound

    NASA Astrophysics Data System (ADS)

    Rankin, Adam; Moore, John; Bainbridge, Daniel; Peters, Terry

    2016-03-01

    In the past ten years, numerous new surgical and interventional techniques have been developed for treating heart valve disease without the need for cardiopulmonary bypass. Heart valve repair is now being performed in a blood-filled environment, reinforcing the need for accurate and intuitive imaging techniques. Previous work has demonstrated how augmenting ultrasound with virtual representations of specific anatomical landmarks can greatly simplify interventional navigation challenges and increase patient safety. These techniques often complicate interventions by requiring additional steps taken to manually define and initialize virtual models. Furthermore, overlaying virtual elements into real-time image data can also obstruct the view of salient image information. To address these limitations, a system was developed that uses real-time volumetric ultrasound alongside magnetically tracked tools presented in an augmented virtuality environment to provide a streamlined navigation guidance platform. In phantom studies simulating a beating-heart navigation task, procedure duration and tool path metrics have achieved comparable performance to previous work in augmented virtuality techniques, and considerable improvement over standard of care ultrasound guidance.

  2. Study of ( α , p ) and ( α , n ) reactions with a Multi-Sampling Ionization Chamber

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

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.

    Here, a large number of (α,p) and (α, n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions 17O (α, n) 20Ne, 23Na (α,p) 26Mg, and 23Na 26Al. These reactions were investigated in inverse kinematics using 4He gas in the detector to study the excitation functions inmore » the energy range of about 2–6 MeV in the center of mass. We found good agreement between the cross sections of the 17O (α, n) 20Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the 23Na (α,p) 26Mg and 23Na (α, n) 26Al reactions.« less

  3. Study of (α , p) and (α , n) reactions with a Multi-Sampling Ionization Chamber

    NASA Astrophysics Data System (ADS)

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Ayangeakaa, A. D.; Dickerson, C.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

    2017-07-01

    A large number of (α , p) and (α , n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions 17O (α , n) 20Ne, 23Na (α , p) 26Mg, and 23Na (α , n) 26Al. These reactions were investigated in inverse kinematics using 4He gas in the detector to study the excitation functions in the energy range of about 2-6 MeV in the center of mass. We found good agreement between the cross sections of the 17O (α , n) 20Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the 23Na (α , p) 26Mg and 23Na (α , n) 26Al reactions.

  4. Study of ( α , p ) and ( α , n ) reactions with a Multi-Sampling Ionization Chamber

    DOE PAGES

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; ...

    2017-04-03

    Here, a large number of (α,p) and (α, n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions 17O (α, n) 20Ne, 23Na (α,p) 26Mg, and 23Na 26Al. These reactions were investigated in inverse kinematics using 4He gas in the detector to study the excitation functions inmore » the energy range of about 2–6 MeV in the center of mass. We found good agreement between the cross sections of the 17O (α, n) 20Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the 23Na (α,p) 26Mg and 23Na (α, n) 26Al reactions.« less

  5. Analysis of a front suspension system for UniART FSAE car using FEA

    NASA Astrophysics Data System (ADS)

    Zaidie, M. N. A.; Hashim, M. S. M.; Tasyrif, M.; Basha, M. H.; Ibrahim, I.; Kamaruddin, N. S.; Shahriman, A. B.

    2017-10-01

    In recent years, many research works from institutions that participated in Formula SAE had highlighted on suspension systems. The aim is to improve the system in term of performance and robustness. However, every suspension system for a racing car is tailored to the car itself. Thus, this paper proposes a new design for front suspension system for UniART FSAE car. The new design was than being compared to the previous suspension system for enhancement. The analysis covered in this paper based on several conditions such as braking, cornering and bumping condition and was carried out using finite element analysis. Each main component for the suspension system such as lower arm, upper arm and knuckle has been analysed in term of strength and performance. From the results, the proposed new design of the suspension system has improved in term of strength and performance compared to the previous suspension system.

  6. Enhanced thermoelectric performance of graphene nanoribbon-based devices

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

    Hossain, Md Sharafat, E-mail: hossain@student.unimelb.edu.au; Huynh, Duc Hau; Nguyen, Phuong Duc

    There have been numerous theoretical studies on exciting thermoelectric properties of graphene nano-ribbons (GNRs); however, most of these studies are mainly based on simulations. In this work, we measure and characterize the thermoelectric properties of GNRs and compare the results with theoretical predictions. Our experimental results verify that nano-structuring and patterning graphene into nano-ribbons significantly enhance its thermoelectric power, confirming previous predictions. Although patterning results in lower conductance (G), the overall power factor (S{sup 2}G) increases for nanoribbons. We demonstrate that edge roughness plays an important role in achieving such an enhanced performance and support it through first principles simulations.more » We show that uncontrolled edge roughness, which is considered detrimental in GNR-based electronic devices, leads to enhanced thermoelectric performance of GNR-based thermoelectric devices. The result validates previously reported theoretical studies of GNRs and demonstrates the potential of GNRs for the realization of highly efficient thermoelectric devices.« less

  7. Work-related stress is associated with impaired neuropsychological test performance: a clinical cross-sectional study.

    PubMed

    Eskildsen, Anita; Andersen, Lars Peter; Pedersen, Anders Degn; Vandborg, Sanne Kjær; Andersen, Johan Hviid

    2015-01-01

    Patients on sick leave due to work-related stress often complain about impaired concentration and memory. However, it is undetermined how widespread these impairments are, and which cognitive domains are most long-term stress sensitive. Previous studies show inconsistent results and are difficult to synthesize. The primary aim of this study was to examine whether patients with work-related stress complaints have cognitive impairments compared to a matched control group without stress. Our secondary aim was to examine whether the level of self-reported perceived stress is associated with neuropsychological test performance. We used a broad neuropsychological test battery to assess 59 outpatients with work-related stress complaints (without major depression) and 59 healthy controls. We matched the patients and controls pairwise by sex, age and educational level. Compared to controls, patients generally showed mildly reduced performance across all the measured domains of the neuropsychological test battery. However, only three comparisons reached statistical significance (p < 0.05). Effect sizes (Cohen's d) were generally small to medium. The most pronounced differences between patients and controls were seen on tests of prospective memory, speed and complex working memory. There were no statistical significant associations between self-reported perceived stress level and neuropsychological test performance. In conclusion, we recommend that cognitive functions should be considered when evaluating patients with work-related stress complaints, especially when given advice regarding return to work. Since this study had a cross-sectional design, it is still uncertain whether the impairments are permanent. Further study is required to establish causal links between work-related stress and cognitive deficits.

  8. Evaluation of questionnaire-based information on previous physical work loads. Stockholm MUSIC 1 Study Group. Musculoskeletal Intervention Center.

    PubMed

    Torgén, M; Winkel, J; Alfredsson, L; Kilbom, A

    1999-06-01

    The principal aim of the present study was to evaluate questionnaire-based information on past physical work loads (6-year recall). Effects of memory difficulties on reproducibility were evaluated for 82 subjects by comparing previously reported results on current work loads (test-retest procedure) with the same items recalled 6 years later. Validity was assessed by comparing self-reports in 1995, regarding work loads in 1989, with worksite measurements performed in 1989. Six-year reproducibility, calculated as weighted kappa coefficients (k(w)), varied between 0.36 and 0.86, with the highest values for proportion of the workday spent sitting and for perceived general exertion and the lowest values for trunk and neck flexion. The six-year reproducibility results were similar to previously reported test-retest results for these items; this finding indicates that memory difficulties was a minor problem. The validity of the questionnaire responses, expressed as rank correlations (r(s)) between the questionnaire responses and workplace measurements, varied between -0.16 and 0.78. The highest values were obtained for the items sitting and repetitive work, and the lowest and "unacceptable" values were for head rotation and neck flexion. Misclassification of exposure did not appear to be differential with regard to musculoskeletal symptom status, as judged by the calculated risk estimates. The validity of some of these self-administered questionnaire items appears sufficient for a crude assessment of physical work loads in the past in epidemiologic studies of the general population with predominantly low levels of exposure.

  9. Greedy Algorithms for Nonnegativity-Constrained Simultaneous Sparse Recovery

    PubMed Central

    Kim, Daeun; Haldar, Justin P.

    2016-01-01

    This work proposes a family of greedy algorithms to jointly reconstruct a set of vectors that are (i) nonnegative and (ii) simultaneously sparse with a shared support set. The proposed algorithms generalize previous approaches that were designed to impose these constraints individually. Similar to previous greedy algorithms for sparse recovery, the proposed algorithms iteratively identify promising support indices. In contrast to previous approaches, the support index selection procedure has been adapted to prioritize indices that are consistent with both the nonnegativity and shared support constraints. Empirical results demonstrate for the first time that the combined use of simultaneous sparsity and nonnegativity constraints can substantially improve recovery performance relative to existing greedy algorithms that impose less signal structure. PMID:26973368

  10. Evaluation of six holmium:YAG optical fibers for ureteroscopy: What's new in 2009?

    NASA Astrophysics Data System (ADS)

    Knudsen, Bodo E.; Teichman, Joel M. H.

    2010-02-01

    The holmium:yttrium aluminum garnet (YAG) laser is the gold standard laser for intracorporeal lithotripsy.1 Optical fibers are utilized to transmit laser energy to the surface of a stone for fragmentation via a predominant photothermal mechanism.2 Previous work has demonstrated that performance characteristics of holmium:YAG optical fibers used for laser lithotripsy varies. Performance may difference not only between fibers made by different manufacturers but also between individual fibers produced by the same manufacturer.3,4 Fiber failure with bending, such as during lower pole ureterorenoscopy, can lead to catastrophic endoscope damage resulting in costly repair. Manufacturers continue to develop new holmium:YAG optical fibers. In this study we evaluate a series of newly commercially available fibers using a previously designed testing protocol. This study was designed to determine the performance and threshold for failure of six newly available holmium:YAG laser fibers from Cook Medical and Fibertech Gmbh. We hypothesize that fiber performance will continue to vary amongst different holmium:YAG optical fibers.

  11. On self-propagating methodological flaws in performance normalization for strength and power sports.

    PubMed

    Arandjelović, Ognjen

    2013-06-01

    Performance in strength and power sports is greatly affected by a variety of anthropometric factors. The goal of performance normalization is to factor out the effects of confounding factors and compute a canonical (normalized) performance measure from the observed absolute performance. Performance normalization is applied in the ranking of elite athletes, as well as in the early stages of youth talent selection. Consequently, it is crucial that the process is principled and fair. The corpus of previous work on this topic, which is significant, is uniform in the methodology adopted. Performance normalization is universally reduced to a regression task: the collected performance data are used to fit a regression function that is then used to scale future performances. The present article demonstrates that this approach is fundamentally flawed. It inherently creates a bias that unfairly penalizes athletes with certain allometric characteristics, and, by virtue of its adoption in the ranking and selection of elite athletes, propagates and strengthens this bias over time. The main flaws are shown to originate in the criteria for selecting the data used for regression, as well as in the manner in which the regression model is applied in normalization. This analysis brings into light the aforesaid methodological flaws and motivates further work on the development of principled methods, the foundations of which are also laid out in this work.

  12. Farm work injuries among a cohort of children in Kentucky, USA.

    PubMed

    Browning, Steven R; Westneat, Susan C; Reed, Deborah B

    2016-12-23

    Children residing on farms with livestock may be at an increased risk for work-related injuries, compared to children who work on other commodity farms. This study characterizes children's work tasks on Kentucky farms and assesses whether children who work on beef cattle farms are at an increased risk for farm work injuries. The results of a cohort study of children aged 5-18 years (N=999 at baseline) working on family farms in Kentucky, followed for two consecutive years after an initial enumeration five years previously, found that 70% of the children were involved in animal-related chores. Across all age groups, children on beef cattle farms devoted a greater number of hours per week to farm work, compared to children living on other commodity farms, especially during the school year. For all children in the study, working more than 180 days per year, performing farm work independently, and working on a beef cattle farm (compared to other commodity farm), increased the risk of a farm work injury. However, none of these associations were statistically significant. For male children only, the performance of work tasks independently was significantly associated with a 2.4-fold increased risk (OR = 2.41; 95% CI: 1.15-5.06; P=0.02) for a farm work injury, after controlling for days of working, age, period of data collection, and commodity type of the farm.

  13. Memory-driven attentional capture reveals the waxing and waning of working memory activation due to dual-task interference.

    PubMed

    Sasin, Edyta; Nieuwenstein, Mark

    2016-12-01

    Previous studies have shown that information held in working memory (WM) actively or as a residue of previous processing can lead to attentional capture by corresponding stimuli in the environment. Here, we compared attentional capture by goal-driven and residual WM activation and examined how these effects are affected by dual-task interference. In two experiments, participants performed an animacy judgment task for a word that they did or did not have to remember for a later recognition test. The word was followed in half of the trials by an arithmetic task that served to disrupt the WM activation of the previously processed word. Subsequently, WM-driven capture was assessed by having participants perform a single-target rapid serial visual presentation task in which a line drawing corresponding to the word was presented shortly before a target. The results showed that the line drawing captured attention irrespective of the presence of the arithmetic task when the word had to be remembered. In comparison, the animacy judgment alone resulted in capture only when the arithmetic task was absent, and this effect was equally strong as the capture effect caused by a to-be-remembered word. Taken together, these findings show that although residual and goal-driven WM activation may be equally potent in guiding attentional selection, these two forms of WM activation differ in that residual activation is overwritten by an attention-demanding task, whereas goal-driven WM activation can lead to the reinstatement of a stimulus after performing such a task.

  14. The neural bases of the effects of item-nonspecific proactive interference in working memory

    PubMed Central

    POSTLE, BRADLEY R.; BRUSH, LAUREN N.

    2005-01-01

    We reanalyzed the behavioral and fMRI data from seven previously published studies of working memory in order to assess the behavioral and neural effects of item-nonspecific proactive interference (PI; attributable to the accrual of antecedent information independent of the repetition of particular items). We hypothesized that item-nonspecific PI, implicated in age-related declines in working memory performance, is mediated by the same mechanism(s) that mediate item-specific PI (occurring when an invalid memory probe matches a memorandum from the previous trial). Reaction time increased across trials as a function of position within the block, a trend that reversed across the duration of each multiblock experiment. The fMRI analyses revealed sensitivity to item-nonspecific PI during the probe epoch in the left anterior inferior frontal gyrus and the left dorsolateral prefrontal cortex (PFC). They also revealed a negative trend, across trials, in the transient probe-evoked component of the global signal. A common PFC-based mechanism may mediate many forms of PI. PMID:15535173

  15. The neural bases of the effects of item-nonspecific proactive interference in working memory.

    PubMed

    Postle, Bradley R; Brush, Lauren N

    2004-09-01

    We reanalyzed the behavioral and fMRI data from seven previously published studies of working memory in order to assess the behavioral and neural effects of item-nonspecific proactive interference (PI; attributable to the accrual of antecedent information independent of the repetition of particular items). We hypothesized that item-nonspecific PI, implicated in age-related declines in working memory performance, is mediated by the same mechanism(s) that mediate item-specific PI (occurring when an invalid memory probe matches a memorandum from the previous trial). Reaction time increased across trials as a function of position within the block, a trend that reversed across the duration of each multiblock experiment. The fMRI analyses revealed sensitivity to item-nonspecific PI during the probe epoch in the left anterior inferior frontal gyrus and the left dorsolateral prefrontal cortex(PFC). They also revealed a negative trend, across trials, in the transient probe-evoked component of the global signal. A common PFC-based mechanism may mediate many forms of PI.

  16. Cold-air investigation of a 4 1/2 stage turbine with stage-loading factor of 4.66 and high specific work output. 2: Stage group performance

    NASA Technical Reports Server (NTRS)

    Whitney, W. J.; Behning, F. P.; Moffitt, T. P.; Hotz, G. M.

    1980-01-01

    The stage group performance of a 4 1/2 stage turbine with an average stage loading factor of 4.66 and high specific work output was determined in cold air at design equivalent speed. The four stage turbine configuration produced design equivalent work output with an efficiency of 0.856; a barely discernible difference from the 0.855 obtained for the complete 4 1/2 stage turbine in a previous investigation. The turbine was designed and the procedure embodied the following design features: (1) controlled vortex flow, (2) tailored radial work distribution, and (3) control of the location of the boundary-layer transition point on the airfoil suction surface. The efficiency forecast for the 4 1/2 stage turbine was 0.886, and the value predicted using a reference method was 0.862. The stage group performance results were used to determine the individual stage efficiencies for the condition at which design 4 1/2 stage work output was obtained. The efficiencies of stages one and four were about 0.020 lower than the predicted value, that of stage two was 0.014 lower, and that of stage three was about equal to the predicted value. Thus all the stages operated reasonably close to their expected performance levels, and the overall (4 1/2 stage) performance was not degraded by any particularly inefficient component.

  17. Relationships among supervisor feedback environment, work-related stressors, and employee deviance.

    PubMed

    Peng, Jei-Chen; Tseng, Mei-Man; Lee, Yin-Ling

    2011-03-01

    Previous research has demonstrated that the employee deviance imposes enormous costs on organizational performance and productivity. Similar research supports the positive effect of favorable supervisor feedback on employee job performance. In light of such, it is important to understand the interaction between supervisor feedback environment and employee deviant behavior to streamline organization operations. The purposes of this study were to explore how the supervisor feedback environment influences employee deviance and to examine the mediating role played by work-related stressors. Data were collected from 276 subordinate-supervisor dyads at a regional hospital in Yilan. Structural equation modeling analyses were conducted to test hypotheses. Structural equation modeling analysis results show that supervisor feedback environment negatively related to interpersonal and organizational deviance. Moreover, work-related stressors were found to partially mediate the relationship between supervisor feedback environment and employee deviance. Study findings suggest that when employees (nurses in this case) perceive an appropriate supervisor-provided feedback environment, their deviance is suppressed because of the related reduction in work-related stressors. Thus, to decrease deviant behavior, organizations may foster supervisor integration of disseminated knowledge such as (a) how to improve employees' actual performance, (b) how to effectively clarify expected performance, and (c) how to improve continuous performance feedback. If supervisors absorb this integrated feedback knowledge, they should be in a better position to enhance their own daily interactions with nurses and reduce nurses' work-related stress and, consequently, decrease deviant behavior.

  18. Do the Contents of Visual Working Memory Automatically Influence Attentional Selection During Visual Search?

    PubMed Central

    Woodman, Geoffrey F.; Luck, Steven J.

    2007-01-01

    In many theories of cognition, researchers propose that working memory and perception operate interactively. For example, in previous studies researchers have suggested that sensory inputs matching the contents of working memory will have an automatic advantage in the competition for processing resources. The authors tested this hypothesis by requiring observers to perform a visual search task while concurrently maintaining object representations in visual working memory. The hypothesis that working memory activation produces a simple but uncontrollable bias signal leads to the prediction that items matching the contents of working memory will automatically capture attention. However, no evidence for automatic attentional capture was obtained; instead, the participants avoided attending to these items. Thus, the contents of working memory can be used in a flexible manner for facilitation or inhibition of processing. PMID:17469973

  19. Do the contents of visual working memory automatically influence attentional selection during visual search?

    PubMed

    Woodman, Geoffrey F; Luck, Steven J

    2007-04-01

    In many theories of cognition, researchers propose that working memory and perception operate interactively. For example, in previous studies researchers have suggested that sensory inputs matching the contents of working memory will have an automatic advantage in the competition for processing resources. The authors tested this hypothesis by requiring observers to perform a visual search task while concurrently maintaining object representations in visual working memory. The hypothesis that working memory activation produces a simple but uncontrollable bias signal leads to the prediction that items matching the contents of working memory will automatically capture attention. However, no evidence for automatic attentional capture was obtained; instead, the participants avoided attending to these items. Thus, the contents of working memory can be used in a flexible manner for facilitation or inhibition of processing.

  20. Mechanical Validation of an MRI Compatible Stereotactic Neurosurgery Robot in Preparation for Pre-Clinical Trials

    PubMed Central

    Nycz, Christopher J; Gondokaryono, Radian; Carvalho, Paulo; Patel, Nirav; Wartenberg, Marek; Pilitsis, Julie G; Fischer, Gregory S

    2018-01-01

    The use of magnetic resonance imaging (MRI) for guiding robotic surgical devices has shown great potential for performing precisely targeted and controlled interventions. To fully realize these benefits, devices must work safely within the tight confines of the MRI bore without negatively impacting image quality. Here we expand on previous work exploring MRI guided robots for neural interventions by presenting the mechanical design and assessment of a device for positioning, orienting, and inserting an interstitial ultrasound-based ablation probe. From our previous work we have added a 2 degree of freedom (DOF) needle driver for use with the aforementioned probe, revised the mechanical design to improve strength and function, and performed an evaluation of the mechanism’s accuracy and effect on MR image quality. The result of this work is a 7-DOF MRI robot capable of positioning a needle tip and orienting it’s axis with accuracy of 1.37 ± 0.06mm and 0.79° ± 0.41°, inserting it along it’s axis with an accuracy of 0.06 ± 0.07mm, and rotating it about it’s axis to an accuracy of 0.77° ± 1.31°. This was accomplished with no significant reduction in SNR caused by the robot’s presence in the MRI bore, ≤ 10.3% reduction in SNR from running the robot’s motors during a scan, and no visible paramagnetic artifacts. PMID:29696097

  1. Allergy to betalactam antibiotics in children: a prospective follow-up study in retreated children after negative responses in skin and challenge tests.

    PubMed

    Ponvert, C; Weilenmann, C; Wassenberg, J; Walecki, P; Bourgeois, M L; de Blic, J; Scheinmann, P

    2007-01-01

    Up to 10% of the patients in whom suspected betalactam hypersensitivity (HS) has been excluded by skin and challenge tests report suspected allergic reactions during subsequent treatments with the same or very similar betalactams. It has been suggested that the reactions may result from a resensitization induced by the challenge performed at the time of the allergological work-up. However, most patients did not undergo a second allergological work-up, to determine if the reactions resulted from betalactam HS or not. We aimed to determine if children diagnosed nonallergic to betalactams have tolerated subsequent treatments with the initially suspected and/or other betalactams, and, in case of a reaction, if the reaction resulted from betalactam HS. We sent a questionnaire concerning the clinical history of their children to the parents of 256 children previously diagnosed nonallergic to betalactams. A second allergological work-up was performed in the children reporting suspected allergic reactions during subsequent treatments with the same and/or other betalactams. Skin tests were performed with the soluble form of the suspected (or very similar) betalactams and other betalactams from the same and other classes. Skin test responses were assessed at 15-20 min (immediate), 6-8 h (semi-late) and 48-72 h (late). Oral challenge (OC) was performed in children with negative skin tests, either at the hospital (immediate and accelerated reactions), or at home (delayed reactions). A response was obtained from 141 children (55.3%). Forty-eight (34%) of those children had not been treated with the betalactams for whom a diagnosis of allergy had been ruled out previously. Seven (7.5%) of the 93 children who had been treated again reported suspected allergic reactions. Skin tests and OC were performed in six of those children, and gave negative results in five children. In one child previously diagnosed nonallergic to amoxicillin associated with clavulanic acid, we diagnosed a delayed HS to clavulanic acid and a serum sickness-like disease to cefaclor. Thus, the frequency of reactions resulting from betalactam HS in children with negative skin and challenge tests is very low, and does not exceed 2.1% (2/93) if we consider that the child which refused a second allergological work-up is really allergic to betalactams. Our results in a very large number of children show that reactions presumed to result from betalactam HS are rare in children in whom the diagnosis of betalactam allergy has been ruled out previously. Moreover, they suggest that, as shown for the initial reactions, most of the reactions during subsequent treatments are rather a consequence of the infectious diseases for whom betalactams have been prescribed than a result of betalactam HS. Finally, they suggest that the risk of resensitization by OC is very low, and do not support the notion that skin testing should be repeated in children diagnosed nonallergic to betalactams.

  2. Augmenting Conceptual Design Trajectory Tradespace Exploration with Graph Theory

    NASA Technical Reports Server (NTRS)

    Dees, Patrick D.; Zwack, Mathew R.; Steffens, Michael; Edwards, Stephen

    2016-01-01

    Within conceptual design changes occur rapidly due to a combination of uncertainty and shifting requirements. To stay relevant in this fluid time, trade studies must also be performed rapidly. In order to drive down analysis time while improving the information gained by these studies, surrogate models can be created to represent the complex output of a tool or tools within a specified tradespace. In order to create this model however, a large amount of data must be collected in a short amount of time. By this method, the historical approach of relying on subject matter experts to generate the data required is schedule infeasible. However, by implementing automation and distributed analysis the required data can be generated in a fraction of the time. Previous work focused on setting up a tool called multiPOST capable of orchestrating many simultaneous runs of an analysis tool assessing these automated analyses utilizing heuristics gleaned from the best practices of current subject matter experts. In this update to the previous work, elements of graph theory are included to further drive down analysis time by leveraging data previously gathered. It is shown to outperform the previous method in both time required, and the quantity and quality of data produced.

  3. Working memory deficits in adults with ADHD: is there evidence for subtype differences?

    PubMed Central

    Schweitzer, Julie B; Hanford, Russell B; Medoff, Deborah R

    2006-01-01

    Background Working memory performance is important for maintaining functioning in cognitive, academic and social activities. Previous research suggests there are prevalent working memory deficits in children with attention deficit hyperactivity disorder (ADHD). There is now a growing body of literature characterizing working memory functioning according to ADHD subtypes in children. The expression of working memory deficits in adults with ADHD and how they vary according to subtype, however, remains to be more fully documented. Methods This study assessed differences in working memory functioning between Normal Control (NC) adults (N = 18); patients with ADHD, Combined (ADHD-CT) Type ADHD (N = 17); and ADHD, Inattentive (ADHD-IA) Type (N = 16) using subtests from the Wechsler Adult Intelligence Scale-III and Wechsler Memory Scale-III and the Paced Auditory Serial Addition Task (PASAT). Results The ADHD groups displayed significant weaknesses in contrast to the NC group on working memory tests requiring rapid processing and active stimulus manipulation. This included the Letter-Number-Sequencing test of the Wechsler scales, PASAT omission errors and the longest sequence of consecutive correct answers on the PASAT. No overall ADHD group subtype differences emerged; however differences between the ADHD groups and the NC group varied depending on the measure and the gender of the participants. Gender differences in performance were evident on some measures of working memory, regardless of group, with males performing better than females. Conclusion In general, the data support a dimensional interpretation of working memory deficits experienced by the ADHD-CT and ADHD-IA subtypes, rather than an absolute difference between subtypes. Future studies should test the effects of processing speed and load on subtype performance and how those variables interact with gender in adults with ADHD. PMID:17173676

  4. Simulations of Tokamak Edge Turbulence Including Self-Consistent Zonal Flows

    NASA Astrophysics Data System (ADS)

    Cohen, Bruce; Umansky, Maxim

    2013-10-01

    Progress on simulations of electromagnetic drift-resistive ballooning turbulence in the tokamak edge is summarized in this mini-conference talk. A more detailed report on this work is presented in a poster at this conference. This work extends our previous work to include self-consistent zonal flows and their effects. The previous work addressed the simulation of L-mode tokamak edge turbulence using the turbulence code BOUT. The calculations used realistic single-null geometry and plasma parameters of the DIII-D tokamak and produced fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes that compare favorably to experimental data. In the effect of sheared ExB poloidal rotation is included with an imposed static radial electric field fitted to experimental data. In the new work here we include the radial electric field self-consistently driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We present simulations with/without zonal flows for both cylindrical geometry, as in the UCLA Large Plasma Device, and for the DIII-D tokamak L-mode cases in to quantify the influence of self-consistent zonal flows on the microturbulence and the concomitant transport. This work was performed under the auspices of the US Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory.

  5. No functional role of attention-based rehearsal in maintenance of spatial working memory representations.

    PubMed

    Belopolsky, Artem V; Theeuwes, Jan

    2009-10-01

    The present study systematically examined the role of attention in maintenance of spatial representations in working memory as proposed by the attention-based rehearsal hypothesis [Awh, E., Jonides, J., & Reuter-Lorenz, P. A. (1998). Rehearsal in spatial working memory. Journal of Experimental Psychology--Human Perception and Performance, 24(3), 780-790]. Three main issues were examined. First, Experiments 1-3 demonstrated that inhibition and not facilitation of visual processing is often observed at the memorized location during the retention interval. This inhibition was caused by keeping a location in memory and not by the exogenous nature of the memory cue. Second, Experiment 4 showed that inhibition of the memorized location does not lead to any significant impairment in memory accuracy. Finally, Experiment 5 connected current results to the previous findings and demonstrated facilitation of processing at the memorized location. Importantly, facilitation of processing did not lead to more accurate memory performance. The present results challenge the functional role of attention in maintenance of spatial working memory representations.

  6. Number word use in toddlerhood is associated with number recall performance at seven years of age.

    PubMed

    Libertus, Melissa E; Marschik, Peter B; Einspieler, Christa

    2014-01-01

    Previous studies have shown that verbal working memory and vocabulary acquisition are linked in early childhood. However, it is unclear whether acquisition of a narrow range of words during toddlerhood may be particularly related to recall of the same words later in life. Here we asked whether vocabulary acquisition of number words, location and quantifier terms over the first three years of life are associated with verbal and visuospatial working memory at seven years. Our results demonstrate that children who produced more number words between 20-26 months and started to produce the number words 1-10 earlier showed greater number recall at 7 years of age. This link was specific to numbers and neither extended to quantifier and location terms nor verbal and visuospatial working memory performance with other stimuli. These findings suggest a category-specific link between the mental lexicon of number words and working memory for numbers at an early age.

  7. An energy efficient and high speed architecture for convolution computing based on binary resistive random access memory

    NASA Astrophysics Data System (ADS)

    Liu, Chen; Han, Runze; Zhou, Zheng; Huang, Peng; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng

    2018-04-01

    In this work we present a novel convolution computing architecture based on metal oxide resistive random access memory (RRAM) to process the image data stored in the RRAM arrays. The proposed image storage architecture shows performances of better speed-device consumption efficiency compared with the previous kernel storage architecture. Further we improve the architecture for a high accuracy and low power computing by utilizing the binary storage and the series resistor. For a 28 × 28 image and 10 kernels with a size of 3 × 3, compared with the previous kernel storage approach, the newly proposed architecture shows excellent performances including: 1) almost 100% accuracy within 20% LRS variation and 90% HRS variation; 2) more than 67 times speed boost; 3) 71.4% energy saving.

  8. Perceptual Optimization of DCT Color Quantization Matrices

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Statler, Irving C. (Technical Monitor)

    1994-01-01

    Many image compression schemes employ a block Discrete Cosine Transform (DCT) and uniform quantization. Acceptable rate/distortion performance depends upon proper design of the quantization matrix. In previous work, we showed how to use a model of the visibility of DCT basis functions to design quantization matrices for arbitrary display resolutions and color spaces. Subsequently, we showed how to optimize greyscale quantization matrices for individual images, for optimal rate/perceptual distortion performance. Here we describe extensions of this optimization algorithm to color images.

  9. On the influence of particle morphology on the post-impact ballistic response of ceramic armour materials

    NASA Astrophysics Data System (ADS)

    Hameed, Amer; Appleby-Thomas, Gareth; Wood, David; Jaansalu, Kevin

    2015-06-01

    Recent studies have shown evidence that the ballistic-resistance of fragmented (comminuted) ceramics is independent of the original strength of the material. In particular, experimental investigations into the ballistic behaviour of such fragmented ceramics have indicated that this response is correlated to shattered ceramic morphology. This suggests that careful control of ceramic microstructure - and therefore failure paths - might provide a route to optimise post-impact ballistic performance, thereby enhancing multi-hit capability. In this study, building on previous in-house work, ballistic tests were conducted using pre-formed `fragmented-ceramic' analogues based around three morphologically differing (but chemically identical) alumina feedstock materials compacted into target `pucks. In an evolution of previous work, variation of target thickness provided additional insight into an apparent morphology-based contribution to ballistic response.

  10. Characteristic of cognitive decline in Parkinson's disease: a 1-year follow-up.

    PubMed

    McKinlay, Audrey; Grace, Randolph C

    2011-10-01

    The aim of this study was to track the evolution of cognitive decline in Parkinson's disease (PD) patients 1 year after baseline testing. Thirty-three PD patients, divided according to three previously determined subgroups based on their initial cognitive performance, and a healthy comparison group were reassessed after a 1-year interval. Participants were assessed in the following five domains: Executive Function, Problem Solving, Working Memory/Attention, Memory, and Visuospatial Ability. The PD groups differed on the domains of Executive Function, Problem Solving, and Working Memory, with the most severe deficits being evident for the group that had previously shown the greatest level of impairment. Increased cognitive problems were also associated with decreased functioning in activities of daily living. The most severely impaired group had evidence of global cognitive decline, possibly reflecting a stage of preclinical dementia.

  11. A model for sequential decoding overflow due to a noisy carrier reference. [communication performance prediction

    NASA Technical Reports Server (NTRS)

    Layland, J. W.

    1974-01-01

    An approximate analysis of the effect of a noisy carrier reference on the performance of sequential decoding is presented. The analysis uses previously developed techniques for evaluating noisy reference performance for medium-rate uncoded communications adapted to sequential decoding for data rates of 8 to 2048 bits/s. In estimating the ten to the minus fourth power deletion probability thresholds for Helios, the model agrees with experimental data to within the experimental tolerances. The computational problem involved in sequential decoding, carrier loop effects, the main characteristics of the medium-rate model, modeled decoding performance, and perspectives on future work are discussed.

  12. Flexibility in Visual Working Memory: Accurate Change Detection in the Face of Irrelevant Variations in Position

    PubMed Central

    Woodman, Geoffrey F.; Vogel, Edward K.; Luck, Steven J.

    2012-01-01

    Many recent studies of visual working memory have used change-detection tasks in which subjects view sequential displays and are asked to report whether they are identical or if one object has changed. A key question is whether the memory system used to perform this task is sufficiently flexible to detect changes in object identity independent of spatial transformations, but previous research has yielded contradictory results. To address this issue, the present study compared standard change-detection tasks with tasks in which the objects varied in size or position between successive arrays. Performance was nearly identical across the standard and transformed tasks unless the task implicitly encouraged spatial encoding. These results resolve the discrepancies in prior studies and demonstrate that the visual working memory system can detect changes in object identity across spatial transformations. PMID:22287933

  13. Work and excessive sleepiness among Brazilian evening high school students: effects on days off.

    PubMed

    Teixeira, Liliane; Lowden, Arne; Moreno, Claudia Roberta; Turte, Samantha; Nagai, Roberta; Latorre, Maria Do Rosário; Valente, Daniel; Fischer, Frida Marina

    2010-01-01

    Previous studies have revealed that students who work and study build up sleep deficits during the workweek, which can trigger a sleep rebound during days off. The objective of this study was to investigate the impact of working/non-working on sleepiness during days off among high school students. The study population, aged 14-21 years, attended evening classes in São Paulo, Brazil. For the study, the students completed questionnaires on living conditions, health, and work; wore actigraphs; and completed the Karolinska Sleepiness Scale (KSS). To predict sleepiness, a logistic regression analysis was performed. Excessive sleepiness was observed on the first day off among working students. Results suggest that working is a significant predictor for sleepiness and that two shifts of daily systematic activities, study and work, might lead to excessive daytime sleepiness on the first day off. Further, this observed excessive sleepiness may reflect the sleep debt accumulated during the workweek.

  14. Failure Engineering Study and Accelerated Stress Test Results for the Mars Global Surveyor Spacecraft's Power Shunt Assemblies

    NASA Technical Reports Server (NTRS)

    Gibbel, Mark; Larson, Timothy

    2000-01-01

    An Engineering-of-Failure approach to designing and executing an accelerated product qualification test was performed to support a risk assessment of a "work-around" necessitated by an on-orbit failure of another piece of hardware on the Mars Global Surveyor spacecraft. The proposed work-around involved exceeding the previous qualification experience both in terms of extreme cold exposure level and in terms of demonstrated low cycle fatigue life for the power shunt assemblies. An analysis was performed to identify potential failure sites, modes and associated failure mechanisms consistent with the new use conditions. A test was then designed and executed which accelerated the failure mechanisms identified by analysis. Verification of the resulting failure mechanism concluded the effort.

  15. Energy absorption in aluminum extrusions for a spaceframe chassis

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

    Logan, R.W.; Perfect, S.A.; Parkinson, R.D.

    1994-09-19

    This work describes the design, finite-element analysis, and verifications performed by LLNL and Kaiser Aluminum for the prototype design of the CALSTART Running Chassis purpose-built electric vehicle. Component level studies, along with our previous experimental and finite-element works, provided the confidence to study the crashworthiness of a complete aluminum spaceframe. Effects of rail geometry, size, and thickness were studied in order to achieve a controlled crush of the front end structure. These included the performance of the spaceframe itself, and the additive effects of the powertrain cradle and powertrain (motor/controller in this case) as well as suspension. Various design iterationsmore » for frontal impact at moderate and high speed are explored.« less

  16. PLSS Scale Demonstration of MTSA Temperature Swing Adsorption Bed Concept for CO2 Removal/Rejection

    NASA Technical Reports Server (NTRS)

    Iacomini, Christine S.; Powers, Aaron; Paul, Heather L.

    2009-01-01

    Metabolic heat regenerated temperature swing adsorption (MTSA) incorporated into a portable life support system (PLSS) is being explored as a viable means of removing and rejecting carbon dioxide (CO2) from an astronaut s ventilation loop. Sorbent pellets used in previous work are inherently difficult to quickly heat and cool. Further, their use in packed beds create large undesirable pressure drop. Thus work has been done to assess the application and performance of aluminum foam wash coated with a layer of sorbent. A to-scale sorbent bed, as envisioned studying use by a Martian PLSS, was designed, built, and tested. Performance of the assembly in regards to CO2 adsorption and pressure drop were assessed and the results are presented.

  17. The Use of a Block Diagram Simulation Language for Rapid Model Prototyping

    NASA Technical Reports Server (NTRS)

    Whitlow, Johnathan E.; Engrand, Peter

    1996-01-01

    The research performed this summer was a continuation of work performed during the 1995 NASA/ASEE Summer Fellowship. The focus of the work was to expand previously generated predictive models for liquid oxygen (LOX) loading into the external fuel tank of the shuttle. The models which were developed using a block diagram simulation language known as VisSim, were evaluated on numerous shuttle flights and found to well in most cases. Once the models were refined and validated, the predictive methods were integrated into the existing Rockwell software propulsion advisory tool (PAT). Although time was not sufficient to completely integrate the models developed into PAT, the ability to predict flows and pressures in the orbiter section and graphically display the results was accomplished.

  18. A Good Beginning

    NASA Astrophysics Data System (ADS)

    Sayre, W. G.; Sayre, Nancy E.

    1999-05-01

    The first-period activity in the classroom is critical for success in the general chemistry course. Past first-day activities at Slippery Rock University have included administering the Toledo test or an in-house mathematics readiness test to help the students understand their degree of readiness for the course. In the past students with poor preparation were shunted into a prep chem course. If no tests were administered then the students received the "this is a university-level course-you must work hard, etc." lecture. This fall the first-period activity was shifted from the intellectual readiness or hard work focus to a behavioral/attitude activity. This resulted in the best performance on the first hour exam in ten years, 2.1 times better than the previous best performance.

  19. Quantity Recognition among Speakers of an Anumeric Language

    ERIC Educational Resources Information Center

    Everett, Caleb; Madora, Keren

    2012-01-01

    Recent research has suggested that the Piraha, an Amazonian tribe with a number-less language, are able to match quantities greater than 3 if the matching task does not require recall or spatial transposition. This finding contravenes previous work among the Piraha. In this study, we re-tested the Pirahas' performance in the crucial one-to-one…

  20. Assessing the Impact of Continuous Evaluation Strategies: Tradeoff between Student Performance and Instructor Effort

    ERIC Educational Resources Information Center

    Poza-Lujan, Jose-Luis; Calafate, Carlos T.; Posadas-Yagüe, Juan-Luis; Cano, Juan-Carlos

    2016-01-01

    Current opinion on undergraduate studies has led to a reformulation of teaching methodologies to base them not just on learning, but also on skills and competencies. In this approach, the teaching/learning process should accomplish both knowledge assimilation and skill development. Previous works demonstrated that a strategy that uses continuous…

  1. THE COMPARISON OF TWO VITRO PALATAL ORGAN CULTURE MODELS TO STUDY CELL SIGNALING PATHWAYS DURING PALATOGENESIS

    EPA Science Inventory

    This study was performed to determine the best palatal organ culture model to use in evaluating the role of epidermal growth factor (EGF) signaling in the response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Previous work has shown that TCDD and EGF can induce teratogenic effe...

  2. Enriching Gender in Physics Education Research: A Binary Past and a Complex Future

    ERIC Educational Resources Information Center

    Traxler, Adrienne L.; Cid, Ximena C.; Blue, Jennifer; Barthelemy, Ramón

    2016-01-01

    In this article, we draw on previous reports from physics, science education, and women's studies to propose a more nuanced treatment of gender in physics education research (PER). A growing body of PER examines gender differences in participation, performance, and attitudes toward physics. We have three critiques of this work: (i) it does not…

  3. Advanced Fiber Optic-Based Sensing Technology for Unmanned Aircraft Systems

    NASA Technical Reports Server (NTRS)

    Richards, Lance; Parker, Allen R.; Piazza, Anthony; Ko, William L.; Chan, Patrick; Bakalyar, John

    2011-01-01

    This presentation provides an overview of fiber optic sensing technology development activities performed at NASA Dryden in support of Unmanned Aircraft Systems. Examples of current and previous work are presented in the following categories: algorithm development, system development, instrumentation installation, ground R&D, and flight testing. Examples of current research and development activities are provided.

  4. Associations among False Belief Understanding, Counterfactual Reasoning, and Executive Function

    ERIC Educational Resources Information Center

    Guajardo, Nicole R.; Parker, Jessica; Turley-Ames, Kandi

    2009-01-01

    The primary purposes of the present study were to clarify previous work on the association between counterfactual thinking and false belief performance to determine (1) whether these two variables are related and (2) if so, whether executive function skills mediate the relationship. A total of 92 3-, 4-, and 5-year-olds completed false belief,…

  5. 30 CFR 48.27 - Training of miners assigned to a task in which they have had no previous experience; minimum...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., drilling machine operators, haulage and conveyor systems operators, ground control machine operators, AMS... practice in the assigned tasks, and the performance of work duties at times or places where production is..., while under direct and immediate supervision and production is in progress, operation of the machine or...

  6. 30 CFR 48.27 - Training of miners assigned to a task in which they have had no previous experience; minimum...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., drilling machine operators, haulage and conveyor systems operators, ground control machine operators, AMS... practice in the assigned tasks, and the performance of work duties at times or places where production is..., while under direct and immediate supervision and production is in progress, operation of the machine or...

  7. 30 CFR 48.27 - Training of miners assigned to a task in which they have had no previous experience; minimum...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., drilling machine operators, haulage and conveyor systems operators, ground control machine operators, AMS... practice in the assigned tasks, and the performance of work duties at times or places where production is..., while under direct and immediate supervision and production is in progress, operation of the machine or...

  8. 30 CFR 48.27 - Training of miners assigned to a task in which they have had no previous experience; minimum...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., drilling machine operators, haulage and conveyor systems operators, ground control machine operators, AMS... practice in the assigned tasks, and the performance of work duties at times or places where production is..., while under direct and immediate supervision and production is in progress, operation of the machine or...

  9. Expert systems research

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

    Duda, R.O.; Shortliffe, E.H.

    1983-04-15

    Artificial intelligence, long a topic of basic computer science research, is now being applied to problems of scientific, technical, and commercial interest. Some consultation programs although limited in versatility, have achieved levels of performance rivaling those of human experts. A collateral benefit of this work is the systematization of previously unformalized knowledge in areas such as medical diagnosis and geology. 30 references.

  10. Analyzing Student Performance in Specific Subject Area Indicators on the ETS Major Field Test in Business

    ERIC Educational Resources Information Center

    Settlage, Daniel Murray; Wollscheid, Jim R.

    2015-01-01

    The Major Field Test is a commonly used assessment instrument, but little emphasis has been put on analyzing student-level subject area indicator scores. The Educational Testing Service recently made these data available to institutions, and it is analyzed here. This analysis builds on previous work by incorporating demographic and programmatic…

  11. Examining the Effects of Residence and Gender on College Student Adjustment in Iran: Implications for Psychotherapists

    ERIC Educational Resources Information Center

    Mohammadi, Mehdi; Schwitzer, Alan M.; Nunnery, John

    2010-01-01

    This study examined the effects of on-campus residence, in comparison with commuter status, on academic performance, vocational commitment, self-efficacy, and perceptions of the college environment among female and male Iranian students at Shiraz University, Iran. The study sought to extend previous work investigating the effects of college…

  12. A Guide for Managers of Child Day Care Agencies.

    ERIC Educational Resources Information Center

    Migrant Opportunity Program, Phoenix, AZ.

    This guide was compiled by a group of rural Arizona day care center managers working under the Migrant Opportunity Program (MOP) established in 1965. The managers were previously inexperienced and, at the end of two years, were interested in self-improvement and more efficient ways to perform their jobs. Their collaboration and idea exchange,…

  13. Variable Delay Testing Using ONE

    NASA Technical Reports Server (NTRS)

    Ishac, Joseph

    2002-01-01

    This paper investigates the effect of long and changing propagation delays on the performance of TCP file transfers. Tests are performed with machines that emulate communication from a low/medium-earth satellite to Earth by way of a geosynchronous satellite. As a result of these tests, we find that TCP is fairly robust to varying delays given a high enough TCP timer granularity. However, performance degrades noticeably for larger file transfers when a finer timer granularity is used. Such results have also been observed in previous simulations by other researchers, and thus, this work serves as an extension of those results.

  14. CDGPS-Based Relative Navigation for Multiple Spacecraft

    NASA Technical Reports Server (NTRS)

    Mitchell, Megan Leigh

    2004-01-01

    This thesis investigates the use of Carrier-phase Differential GPS (CDGPS) in relative navigation filters for formation flying spacecraft. This work analyzes the relationship between the Extended Kalman Filter (EKF) design parameters and the resulting estimation accuracies, and in particular, the effect of the process and measurement noises on the semimajor axis error. This analysis clearly demonstrates that CDGPS-based relative navigation Kalman filters yield good estimation performance without satisfying the strong correlation property that previous work had associated with "good" navigation filters. Several examples are presented to show that the Kalman filter can be forced to create solutions with stronger correlations, but these always result in larger semimajor axis errors. These linear and nonlinear simulations also demonstrated the crucial role of the process noise in determining the semimajor axis knowledge. More sophisticated nonlinear models were included to reduce the propagation error in the estimator, but for long time steps and large separations, the EKF, which only uses a linearized covariance propagation, yielded very poor performance. In contrast, the CDGPS-based Unscented Kalman relative navigation Filter (UKF) handled the dynamic and measurement nonlinearities much better and yielded far superior performance than the EKF. The UKF produced good estimates for scenarios with long baselines and time steps for which the EKF would diverge rapidly. A hardware-in-the-loop testbed that is compatible with the Spirent Simulator at NASA GSFC was developed to provide a very flexible and robust capability for demonstrating CDGPS technologies in closed-loop. This extended previous work to implement the decentralized relative navigation algorithms in real time.

  15. Evaluation of superconducting wiggler designs and free-electron laser support: Final report

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

    NONE

    1990-10-12

    This report consists of copies of previous progress reports, and copies of viewgraphs presented in a talk at Los Alamos. The report describes activities carried out as part of a project to evaluate the design and performance of a superconducting wiggler magnet design. It includes work on evaluating the appropriate materials for the magnet coils and poles, and stress evaluations for the design. It includes work on beam optics through the magnet, and design considerations to optimize extraction: work on the cryocooling system; weight minimization efforts; and design work on the vacuum liner for the magnet. A major concern inmore » all of this design work is heat loads which will be dissipated in different parts of the system during operation, as well as transient events.« less

  16. Working memory-driven attention improves spatial resolution: Support for perceptual enhancement.

    PubMed

    Pan, Yi; Luo, Qianying; Cheng, Min

    2016-08-01

    Previous research has indicated that attention can be biased toward those stimuli matching the contents of working memory and thereby facilitates visual processing at the location of the memory-matching stimuli. However, whether this working memory-driven attentional modulation takes place on early perceptual processes remains unclear. Our present results showed that working memory-driven attention improved identification of a brief Landolt target presented alone in the visual field. Because the suprathreshold target appeared without any external noise added (i.e., no distractors or masks), the results suggest that working memory-driven attention enhances the target signal at early perceptual stages of visual processing. Furthermore, given that performance in the Landolt target identification task indexes spatial resolution, this attentional facilitation indicates that working memory-driven attention can boost early perceptual processing via enhancement of spatial resolution at the attended location.

  17. The Priority Inversion Problem and Real-Time Symbolic Model Checking

    DTIC Science & Technology

    1993-04-23

    real time systems unpredictable in subtle ways. This makes it more difficult to implement and debug such systems. Our work discusses this problem and presents one possible solution. The solution is formalized and verified using temporal logic model checking techniques. In order to perform the verification, the BDD-based symbolic model checking algorithm given in previous works was extended to handle real-time properties using the bounded until operator. We believe that this algorithm, which is based on discrete time, is able to handle many real-time properties

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

    Chadwick, M. B.; Capote, R.; Trkov, A.

    The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235;8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

  19. Excitation spectra of liquid iron up to superhigh temperatures

    NASA Astrophysics Data System (ADS)

    Fomin, Yu D.; Ryzhov, V. N.; Tsiok, E. N.; Brazhkin, V. V.

    2017-08-01

    Investigation of excitation spectra of liquids is one of the hot test topics nowadays. In particular, recent experimental works showed that liquid metals can demonstrate transverse excitations and positive sound dispersion. However, the theoretical description of these experimental observations is still missing. Here we report a molecular dynamics study of excitation spectra of liquid iron. We compare the results with available experimental data to justify the method. After that we perform calculations for high temperatures to find the location of the Frenkel line introduced in our previous works.

  20. Structural properties of lead-lithium alloys

    NASA Astrophysics Data System (ADS)

    Khambholja, S. G.; Satikunvar, D. D.; Abhishek, Agraj; Thakore, B. Y.

    2018-05-01

    Lead-Lihtium alloys have found large number of applications as liquid metal coolants in nuclear reactors. Large number of experimental work is reported for this system. However, complete theoretical description is still rare. In this scenario, we in the present work report the study of ground state properties of Lead-Lithium system. The present study is performed using plane wave pseudopotential density functional theory as implemented in Quantum ESPRESSO package. The theoretical findings are in agreement with previously reported experimental data. Some conclusions are drawn based on present study, which will be helpful for a comprehensive study.

  1. Increased neuromuscular consistency in gait and balance after partnered, dance-based rehabilitation in Parkinson's disease.

    PubMed

    Allen, Jessica L; McKay, J Lucas; Sawers, Andrew; Hackney, Madeleine E; Ting, Lena H

    2017-07-01

    Here we examined changes in muscle coordination associated with improved motor performance after partnered, dance-based rehabilitation in individuals with mild to moderate idiopathic Parkinson's disease. Using motor module (a.k.a. muscle synergy) analysis, we identified changes in the modular control of overground walking and standing reactive balance that accompanied clinically meaningful improvements in behavioral measures of balance, gait, and disease symptoms after 3 wk of daily Adapted Tango classes. In contrast to previous studies that revealed a positive association between motor module number and motor performance, none of the six participants in this pilot study increased motor module number despite improvements in behavioral measures of balance and gait performance. Instead, motor modules were more consistently recruited and distinctly organized immediately after rehabilitation, suggesting more reliable motor output. Furthermore, the pool of motor modules shared between walking and reactive balance increased after rehabilitation, suggesting greater generalizability of motor module function across tasks. Our work is the first to show that motor module distinctness, consistency, and generalizability are more sensitive to improvements in gait and balance function after short-term rehabilitation than motor module number. Moreover, as similar differences in motor module distinctness, consistency, and generalizability have been demonstrated previously in healthy young adults with and without long-term motor training, our work suggests commonalities in the structure of muscle coordination associated with differences in motor performance across the spectrum from motor impairment to expertise. NEW & NOTEWORTHY We demonstrate changes in neuromuscular control of gait and balance in individuals with Parkinson's disease after short-term, dance-based rehabilitation. Our work is the first to show that motor module distinctness, consistency, and generalizability across gait and balance are more sensitive than motor module number to improvements in motor performance following short-term rehabilitation. Our results indicate commonalities in muscle coordination improvements associated with motor skill reacquisition due to rehabilitation and motor skill acquisition in healthy individuals. Copyright © 2017 the American Physiological Society.

  2. Analysis of the faster-than-Nyquist optimal linear multicarrier system

    NASA Astrophysics Data System (ADS)

    Marquet, Alexandre; Siclet, Cyrille; Roque, Damien

    2017-02-01

    Faster-than-Nyquist signalization enables a better spectral efficiency at the expense of an increased computational complexity. Regarding multicarrier communications, previous work mainly relied on the study of non-linear systems exploiting coding and/or equalization techniques, with no particular optimization of the linear part of the system. In this article, we analyze the performance of the optimal linear multicarrier system when used together with non-linear receiving structures (iterative decoding and direct feedback equalization), or in a standalone fashion. We also investigate the limits of the normality assumption of the interference, used for implementing such non-linear systems. The use of this optimal linear system leads to a closed-form expression of the bit-error probability that can be used to predict the performance and help the design of coded systems. Our work also highlights the great performance/complexity trade-off offered by decision feedback equalization in a faster-than-Nyquist context. xml:lang="fr"

  3. Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

    PubMed

    Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

    2014-05-01

    Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

  4. Improving cerebellar segmentation with statistical fusion

    NASA Astrophysics Data System (ADS)

    Plassard, Andrew J.; Yang, Zhen; Prince, Jerry L.; Claassen, Daniel O.; Landman, Bennett A.

    2016-03-01

    The cerebellum is a somatotopically organized central component of the central nervous system well known to be involved with motor coordination and increasingly recognized roles in cognition and planning. Recent work in multiatlas labeling has created methods that offer the potential for fully automated 3-D parcellation of the cerebellar lobules and vermis (which are organizationally equivalent to cortical gray matter areas). This work explores the trade offs of using different statistical fusion techniques and post hoc optimizations in two datasets with distinct imaging protocols. We offer a novel fusion technique by extending the ideas of the Selective and Iterative Method for Performance Level Estimation (SIMPLE) to a patch-based performance model. We demonstrate the effectiveness of our algorithm, Non- Local SIMPLE, for segmentation of a mixed population of healthy subjects and patients with severe cerebellar anatomy. Under the first imaging protocol, we show that Non-Local SIMPLE outperforms previous gold-standard segmentation techniques. In the second imaging protocol, we show that Non-Local SIMPLE outperforms previous gold standard techniques but is outperformed by a non-locally weighted vote with the deeper population of atlases available. This work advances the state of the art in open source cerebellar segmentation algorithms and offers the opportunity for routinely including cerebellar segmentation in magnetic resonance imaging studies that acquire whole brain T1-weighted volumes with approximately 1 mm isotropic resolution.

  5. Differential Lipid Composition and Gene Expression in the Semi-Russeted “Cox Orange Pippin” Apple Variety

    PubMed Central

    Legay, Sylvain; Cocco, Emmanuelle; André, Christelle M.; Guignard, Cédric; Hausman, Jean-Francois; Guerriero, Gea

    2017-01-01

    Russeting is characterized by a particular rough and brown phenotype, which is mainly due to the accumulation of suberin in the inner part of the epidermal cell walls. In our previous bulk transcriptomic analysis, comparing fully russeted, and waxy apple varieties, showed, in apple fruit skin, a massive decreased expression of cutin, wax and some pentacyclic triterpene biosynthesis genes in the russeted varieties, with an expected concomitant enhanced expression of the suberin biosynthetic genes. In the present work, we performed a deep investigation of the aliphatic composition of the cutin, suberin, waxes, and triterpenes in the waxy and russeted patches of the semi-russeted apple variety “Cox Orange Pippin.” A targeted gene expression profiling was performed to validate candidate genes which were identified in our previous work and might be involved in the respective metabolic pathways. Our results showed that a decrease of cuticular waxes, ursolic acid and oleanolic acid, accompanied by an accumulation of alkyl-hydroxycinamates and betulinic acid, occurs in the russeted patches. The suberin monomer composition is characterized by specific occurrence of 20, 22, and 24 carbon aliphatic chains, whereas cutin is mainly represented by common C16 and C18 aliphatic chains. This work depicts, for the first time in apple, the complex composition of suberin, cutin, waxes and triterpenes, and confirms the strong interplay between these epidermal polymers in apple fruit skin. PMID:29018466

  6. Cognitive and Linguistic Sources of Variance in 2-Year-Olds’ Speech-Sound Discrimination: A Preliminary Investigation

    PubMed Central

    Lalonde, Kaylah; Holt, Rachael Frush

    2017-01-01

    Purpose This preliminary investigation explored potential cognitive and linguistic sources of variance in 2-year-olds’ speech-sound discrimination by using the toddler change/no-change procedure and examined whether modifications would result in a procedure that can be used consistently with younger 2-year-olds. Method Twenty typically developing 2-year-olds completed the newly modified toddler change/no-change procedure. Behavioral tests and parent report questionnaires were used to measure several cognitive and linguistic constructs. Stepwise linear regression was used to relate discrimination sensitivity to the cognitive and linguistic measures. In addition, discrimination results from the current experiment were compared with those from 2-year-old children tested in a previous experiment. Results Receptive vocabulary and working memory explained 56.6% of variance in discrimination performance. Performance was not different on the modified toddler change/no-change procedure used in the current experiment from in a previous investigation, which used the original version of the procedure. Conclusions The relationship between speech discrimination and receptive vocabulary and working memory provides further evidence that the procedure is sensitive to the strength of perceptual representations. The role for working memory might also suggest that there are specific subject-related, nonsensory factors limiting the applicability of the procedure to children who have not reached the necessary levels of cognitive and linguistic development. PMID:24023371

  7. Cognitive and linguistic sources of variance in 2-year-olds’ speech-sound discrimination: a preliminary investigation.

    PubMed

    Lalonde, Kaylah; Holt, Rachael Frush

    2014-02-01

    This preliminary investigation explored potential cognitive and linguistic sources of variance in 2-year-olds’ speech-sound discrimination by using the toddler change/ no-change procedure and examined whether modifications would result in a procedure that can be used consistently with younger 2-year-olds. Twenty typically developing 2-year-olds completed the newly modified toddler change/no-change procedure. Behavioral tests and parent report questionnaires were used to measure several cognitive and linguistic constructs. Stepwise linear regression was used to relate discrimination sensitivity to the cognitive and linguistic measures. In addition, discrimination results from the current experiment were compared with those from 2-year-old children tested in a previous experiment. Receptive vocabulary and working memory explained 56.6% of variance in discrimination performance. Performance was not different on the modified toddler change/no-change procedure used in the current experiment from in a previous investigation, which used the original version of the procedure. The relationship between speech discrimination and receptive vocabulary and working memory provides further evidence that the procedure is sensitive to the strength of perceptual representations. The role for working memory might also suggest that there are specific subject-related, nonsensory factors limiting the applicability of the procedure to children who have not reached the necessary levels of cognitive and linguistic development.

  8. Differential Lipid Composition and Gene Expression in the Semi-Russeted "Cox Orange Pippin" Apple Variety.

    PubMed

    Legay, Sylvain; Cocco, Emmanuelle; André, Christelle M; Guignard, Cédric; Hausman, Jean-Francois; Guerriero, Gea

    2017-01-01

    Russeting is characterized by a particular rough and brown phenotype, which is mainly due to the accumulation of suberin in the inner part of the epidermal cell walls. In our previous bulk transcriptomic analysis, comparing fully russeted, and waxy apple varieties, showed, in apple fruit skin, a massive decreased expression of cutin, wax and some pentacyclic triterpene biosynthesis genes in the russeted varieties, with an expected concomitant enhanced expression of the suberin biosynthetic genes. In the present work, we performed a deep investigation of the aliphatic composition of the cutin, suberin, waxes, and triterpenes in the waxy and russeted patches of the semi-russeted apple variety "Cox Orange Pippin." A targeted gene expression profiling was performed to validate candidate genes which were identified in our previous work and might be involved in the respective metabolic pathways. Our results showed that a decrease of cuticular waxes, ursolic acid and oleanolic acid, accompanied by an accumulation of alkyl-hydroxycinamates and betulinic acid, occurs in the russeted patches. The suberin monomer composition is characterized by specific occurrence of 20, 22, and 24 carbon aliphatic chains, whereas cutin is mainly represented by common C16 and C18 aliphatic chains. This work depicts, for the first time in apple, the complex composition of suberin, cutin, waxes and triterpenes, and confirms the strong interplay between these epidermal polymers in apple fruit skin.

  9. Development and evaluation of a decision-based simulation for assessment of team skills.

    PubMed

    Andrew, Brandon; Plachta, Stephen; Salud, Lawrence; Pugh, Carla M

    2012-08-01

    There is a need to train and evaluate a wide variety of nontechnical surgical skills. The goal of this project was to develop and evaluate a decision-based simulation to assess team skills. The decision-based exercise used our previously validated Laparoscopic Ventral Hernia simulator and a newly developed team evaluation survey. Five teams of 3 surgical residents (N = 15) were tasked with repairing a 10 × 10-cm right upper quadrant hernia. During the simulation, independent observers (N = 6) completed a 6-item survey assessing: (1) work quality; (2) communication; and (3) team effectiveness. After the simulation, team members self-rated their performance by using the same survey. Survey reliability revealed a Cronbach's alpha of r = .811. Significant differences were found when we compared team members' (T) and observers' (O) ratings for communication (T = 4.33/5.00 vs O = 3.00/5.00, P < .01) and work quality (T = 4.33/5.00 vs O = 3.33/5.00, P < .05). The team with the greatest survey ratings was the only group to successfully complete the task. The team evaluation survey had good reliability and correlated with task performance on the simulator. Our current and previous work provides strong evidence that nontechnical and team related skills can be assessed without simulating a crisis situation. Copyright © 2012 Mosby, Inc. All rights reserved.

  10. Synthesis and Characterization of ZnO/polymer planar heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Gutierrez, Leandro; Manners, William; Nabizadeh, Arya; Albers, Patrick; Duran, Jesus; Scudieri, Anthony; Isah, Anne; McDougall, Michael; Sahiner, Mehmet; Wang, Weining

    2014-03-01

    ZnO/polymer heterojunction has been studied by many groups for its potential application in solar cell, LED, UV photodetection and other applications. However, there are few studies on ZnO/polymer heterojunction by synthesizing ZnO using pulsed laser deposition (PLD). Comparing with other methods, PLD has the advantage of congruent evaporation, and being able to grow high quality thin films at relatively low temperature. In our previous work in pulsed-laser-deposited (PLD) ZnO/PEDOT:PSS heterojunction, correlations between the annealing conditions of pulsed laser deposition and the electrical performance of solar cells have been observed. In this work, we report two new studies: 1) Studies on how the performance of the PLD-ZnO /PEDOT:PSS heterojunction depends on polymer conductivity; 2) Comparison studies on PLD-ZnO/PEDOT:PSS and PLD-ZnO/P3HT heterojunction. We studied how the performance of ZnO/polymer solar cells depend on the polymer work function and conductivities and deposition condition of ZnO. X-ray diffraction (XRD) and scanning electron microscopy were used to characterize the PLD-ZnO film. The correlation between the solar cell electrical performance and the polymer conductivity and pulsed laser deposition conditions will be discussed.

  11. Argonne Bubble Experiment Thermal Model Development III

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

    Buechler, Cynthia Eileen

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development” and “Argonne Bubble Experiment Thermal Model Development II”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at beam power levels between 6 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was recorded. The previous report2 described the Monte-Carlo N-Particle (MCNP) calculations and Computational Fluid Dynamics (CFD) analysis performed on the as-built solution vesselmore » geometry. The CFD simulations in the current analysis were performed using Ansys Fluent, Ver. 17.2. The same power profiles determined from MCNP calculations in earlier work were used for the 12 and 15 kW simulations. The primary goal of the current work is to calculate the temperature profiles for the 12 and 15 kW cases using reasonable estimates for the gas generation rate, based on images of the bubbles recorded during the irradiations. Temperature profiles resulting from the CFD calculations are compared to experimental measurements.« less

  12. Venting and High Vacuum Performance of Low Density Multilayer Insulation

    NASA Astrophysics Data System (ADS)

    Riesco, M. E.; McLean, C. H.; Mills, G. L.; Buerger, S.; Meyer, M. L.

    2010-04-01

    The NASA Exploration Program is currently studying the use liquid oxygen, liquid methane and liquid hydrogen for propulsion in future spacecraft for Exploration of the Moon and Mars. This will require the efficient long term, on-orbit storage of these cryogenic propellants. Multilayer Insulation (MLI) will be critical to achieving the required thermal performance since it has much lower heat transfer than any other insulation when used in a vacuum. MLI with a low density (⩽10 layers/cm) has been shown in previous work to be the most mass efficient. The size and mass constraints of these propulsion systems will not allow a structural shell to be used to provide vacuum for the MLI during ground hold and launch. The baseline approach is to purge the MLI during ground hold with an inert gas which is then vented during launch ascent and on-orbit. This paper presents the results on experimental tests and modeling performed by Ball Aerospace on low density, non-perforated MLI used to insulate a cryogenic tank simulating an Exploration cryogenic propellant storage vessel. These include measurements of the rate of venting and of the heat transfer of gas filled insulation, fully evacuated insulation and during the transition in between. Results of transient computer modeling of the MLI venting and heat transfer process are also presented. Previous work by some of the authors performed vent testing using MLI with perforations and slits and a slow pump down rate.

  13. Stochastic model predicts evolving preferences in the Iowa gambling task

    PubMed Central

    Fuentes, Miguel A.; Lavín, Claudio; Contreras-Huerta, L. Sebastián; Miguel, Hernan; Rosales Jubal, Eduardo

    2014-01-01

    Learning under uncertainty is a common task that people face in their daily life. This process relies on the cognitive ability to adjust behavior to environmental demands. Although the biological underpinnings of those cognitive processes have been extensively studied, there has been little work in formal models seeking to capture the fundamental dynamic of learning under uncertainty. In the present work, we aimed to understand the basic cognitive mechanisms of outcome processing involved in decisions under uncertainty and to evaluate the relevance of previous experiences in enhancing learning processes within such uncertain context. We propose a formal model that emulates the behavior of people playing a well established paradigm (Iowa Gambling Task - IGT) and compare its outcome with a behavioral experiment. We further explored whether it was possible to emulate maladaptive behavior observed in clinical samples by modifying the model parameter which controls the update of expected outcomes distributions. Results showed that the performance of the model resembles the observed participant performance as well as IGT performance by healthy subjects described in the literature. Interestingly, the model converges faster than some subjects on the decks with higher net expected outcome. Furthermore, the modified version of the model replicated the trend observed in clinical samples performing the task. We argue that the basic cognitive component underlying learning under uncertainty can be represented as a differential equation that considers the outcomes of previous decisions for guiding the agent to an adaptive strategy. PMID:25566043

  14. Stochastic model predicts evolving preferences in the Iowa gambling task.

    PubMed

    Fuentes, Miguel A; Lavín, Claudio; Contreras-Huerta, L Sebastián; Miguel, Hernan; Rosales Jubal, Eduardo

    2014-01-01

    Learning under uncertainty is a common task that people face in their daily life. This process relies on the cognitive ability to adjust behavior to environmental demands. Although the biological underpinnings of those cognitive processes have been extensively studied, there has been little work in formal models seeking to capture the fundamental dynamic of learning under uncertainty. In the present work, we aimed to understand the basic cognitive mechanisms of outcome processing involved in decisions under uncertainty and to evaluate the relevance of previous experiences in enhancing learning processes within such uncertain context. We propose a formal model that emulates the behavior of people playing a well established paradigm (Iowa Gambling Task - IGT) and compare its outcome with a behavioral experiment. We further explored whether it was possible to emulate maladaptive behavior observed in clinical samples by modifying the model parameter which controls the update of expected outcomes distributions. Results showed that the performance of the model resembles the observed participant performance as well as IGT performance by healthy subjects described in the literature. Interestingly, the model converges faster than some subjects on the decks with higher net expected outcome. Furthermore, the modified version of the model replicated the trend observed in clinical samples performing the task. We argue that the basic cognitive component underlying learning under uncertainty can be represented as a differential equation that considers the outcomes of previous decisions for guiding the agent to an adaptive strategy.

  15. Weight and See: Loading Working Memory Improves Incidental Identification of Irrelevant Faces

    PubMed Central

    Carmel, David; Fairnie, Jake; Lavie, Nilli

    2012-01-01

    Are task-irrelevant stimuli processed to a level enabling individual identification? This question is central both for perceptual processing models and for applied settings (e.g., eye-witness testimony). Lavie’s load theory proposes that working memory actively maintains attentional prioritization of relevant over irrelevant information. Loading working memory thus impairs attentional prioritization, leading to increased processing of task-irrelevant stimuli. Previous research has shown that increased working memory load leads to greater interference effects from response-competing distractors. Here we test the novel prediction that increased processing of irrelevant stimuli under high working memory load should lead to a greater likelihood of incidental identification of entirely irrelevant stimuli. To test this, we asked participants to perform a word-categorization task while ignoring task-irrelevant images. The categorization task was performed during the retention interval of a working memory task with either low or high load (defined by memory set size). Following the final experimental trial, a surprise question assessed incidental identification of the irrelevant image. Loading working memory was found to improve identification of task-irrelevant faces, but not of building stimuli (shown in a separate experiment to be less distracting). These findings suggest that working memory plays a critical role in determining whether distracting stimuli will be subsequently identified. PMID:22912623

  16. Rhythm synchronization performance and auditory working memory in early- and late-trained musicians.

    PubMed

    Bailey, Jennifer A; Penhune, Virginia B

    2010-07-01

    Behavioural and neuroimaging studies provide evidence for a possible "sensitive" period in childhood development during which musical training results in long-lasting changes in brain structure and auditory and motor performance. Previous work from our laboratory has shown that adult musicians who begin training before the age of 7 (early-trained; ET) perform better on a visuomotor task than those who begin after the age of 7 (late-trained; LT), even when matched on total years of musical training and experience. Two questions were raised regarding the findings from this experiment. First, would this group performance difference be observed using a more familiar, musically relevant task such as auditory rhythms? Second, would cognitive abilities mediate this difference in task performance? To address these questions, ET and LT musicians, matched on years of musical training, hours of current practice and experience, were tested on an auditory rhythm synchronization task. The task consisted of six woodblock rhythms of varying levels of metrical complexity. In addition, participants were tested on cognitive subtests measuring vocabulary, working memory and pattern recognition. The two groups of musicians differed in their performance of the rhythm task, such that the ET musicians were better at reproducing the temporal structure of the rhythms. There were no group differences on the cognitive measures. Interestingly, across both groups, individual task performance correlated with auditory working memory abilities and years of formal training. These results support the idea of a sensitive period during the early years of childhood for developing sensorimotor synchronization abilities via musical training.

  17. Managers' social support: Facilitators and hindrances for seeking support at work.

    PubMed

    Lundqvist, Daniel; Fogelberg Eriksson, Anna; Ekberg, Kerstin

    2018-01-01

    Previous research has shown that social support is important for health and performance at work, but there is a lack of research regarding managers' social support at work, and if it needs to be improvedOBJECTIVE:To investigate managers' perception of work-related social support, and facilitators and hindrances that influence their seeking of social support at work. Semi-structured interviews with sixty-two managers in two Swedish organizations. Work-related support, which strengthened their managerial image of being competent, was sought from sources within the workplace. Sensitive and personal support, where there was a risk of jeopardizing their image of being competent, was sought from sources outside the workplace. Access to arenas for support (location of the workplace, meetings, and vocational courses) and the managerial role could facilitate their support-seeking, but could also act as hindrances. Because attending different arenas for support were demanding, they refrained from seeking support if the demands were perceived as too high. Different supportive sources are distinguished based on what supportive function they have and in which arenas they are found, in order to preserve the confidence of the closest organization and to maintain the image of being a competent and performing manager.

  18. Effect of a single dose of dextromethorphan on psychomotor performance and working memory capacity.

    PubMed

    Al-Kuraishy, Hayder M; Al-Gareeb, Ali I; Ashor, Ammar Waham

    2012-04-01

    Previous studies show that the prolonged use of dextromethorphan produces cognitive deterioration in humans. The aim of this study was to investigate the effect of a single dose of dextroemthrophan on psychomotor performance and working memory capacity. This is a randomized, double-blind, controlled, and prospective study. Thirty-six (17 women, 19 men) medical students enrolled in the study; half of them (7 women, 11 men) were given placebo, while the other half (10 women, 8 men) received dextromethorphan. The choice reaction time, critical flicker fusion threshold, and N-back working memory task were measured before and after 2 h of taking the drugs. Dextromethorphan showed a significant deterioration in the 3-back working memory task (P<0.05). No significant changes were seen as regards the choice reaction time components (total, recognition, motor) and critical flicker fusion threshold (P>0.05). On the other hand, placebo showed no significant changes as regards the choice reaction time, critical flicker fusion threshold, and N-back working memory task (P>0.05). A single dose of dextromethorphan has no effect on attention and arousal but may significantly impair the working memory capacity.

  19. Polymorphisms in HLA-DPB1 Are Associated With Differences in Rubella Virus–Specific Humoral Immunity After Vaccination

    PubMed Central

    Lambert, Nathaniel D.; Haralambieva, Iana H.; Kennedy, Richard B.; Ovsyannikova, Inna G.; Pankratz, Vernon Shane; Poland, Gregory A.

    2015-01-01

    Vaccination with live attenuated rubella virus induces a strong immune response in most individuals. However, small numbers of subjects never reach or maintain protective antibody levels, and there is a high degree of variability in immune response. We have previously described genetic polymorphisms in HLA and other candidate genes that are associated with interindividual differences in humoral immunity to rubella virus. To expand our previous work, we performed a genome-wide association study (GWAS) to discover single-nucleotide polymorphisms (SNPs) associated with rubella virus–specific neutralizing antibodies. We identified rs2064479 in the HLA-DPB1 genetic region as being significantly associated with humoral immune response variations after rubella vaccination (P = 8.62 × 10−8). All other significant SNPs in this GWAS were located near the HLA-DPB1 gene (P ≤ 1 × 10−7). These findings demonstrate that polymorphisms in HLA-DPB1 are strongly associated with interindividual differences in neutralizing antibody levels to rubella vaccination and represent a validation of our previous HLA work. PMID:25293367

  20. Interactive videodisc instruction is an alternative method for learning and performing a critical nursing skill.

    PubMed

    DeAmicis, P A

    1997-01-01

    A study was conducted to compare the effectiveness of interactive videodisc instruction (IVDI) with the traditional lecture/demonstration as an alternative method for learning and performing a critical nursing skill. Students were assigned randomly to a treatment group that worked in small groups to complete the IVDI on intravenous therapy skills and a control group receiving the same content in a classroom lecture/demonstration format. After the instruction, each subject performed a re-demonstration of the learned skills using specific guidelines. Results revealed that although the IVDI group scored higher on the overall re-demonstration, there was no significant difference in the ability of the two groups to effectively perform this critical nursing skill. These findings support the use of IVDI as an alternative self-paced, independent study method for learning psychomotor skills and are consistent with previous studies, which indicate that working in small groups on the computer has a positive effect on self-efficacy and achievement.

  1. Reproducibility and Variability of I/O Performance on BG/Q: Lessons Learned from a Data Aggregation Algorithm

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

    Tessier, Francois; Vishwanath, Venkatram

    2017-11-28

    Reading and writing data efficiently from different tiers of storage is necessary for most scientific simulations to achieve good performance at scale. Many software solutions have been developed to decrease the I/O bottleneck. One wellknown strategy, in the context of collective I/O operations, is the two-phase I/O scheme. This strategy consists of selecting a subset of processes to aggregate contiguous pieces of data before performing reads/writes. In our previous work, we implemented the two-phase I/O scheme with a MPI-based topology-aware algorithm. Our algorithm showed very good performance at scale compared to the standard I/O libraries such as POSIX I/O andmore » MPI I/O. However, the algorithm had several limitations hindering a satisfying reproducibility of our experiments. In this paper, we extend our work by 1) identifying the obstacles we face to reproduce our experiments and 2) discovering solutions that reduce the unpredictability of our results.« less

  2. Changing the precision of preschoolers' approximate number system representations changes their symbolic math performance.

    PubMed

    Wang, Jinjing Jenny; Odic, Darko; Halberda, Justin; Feigenson, Lisa

    2016-07-01

    From early in life, humans have access to an approximate number system (ANS) that supports an intuitive sense of numerical quantity. Previous work in both children and adults suggests that individual differences in the precision of ANS representations correlate with symbolic math performance. However, this work has been almost entirely correlational in nature. Here we tested for a causal link between ANS precision and symbolic math performance by asking whether a temporary modulation of ANS precision changes symbolic math performance. First, we replicated a recent finding that 5-year-old children make more precise ANS discriminations when starting with easier trials and gradually progressing to harder ones, compared with the reverse. Next, we show that this brief modulation of ANS precision influenced children's performance on a subsequent symbolic math task but not a vocabulary task. In a supplemental experiment, we present evidence that children who performed ANS discriminations in a random trial order showed intermediate performance on both the ANS task and the symbolic math task, compared with children who made ordered discriminations. Thus, our results point to a specific causal link from the ANS to symbolic math performance. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Changing the precision of preschoolers’ approximate number system representations changes their symbolic math performance

    PubMed Central

    Wang, Jinjing (Jenny); Odic, Darko; Halberda, Justin; Feigenson, Lisa

    2016-01-01

    From early in life, humans have access to an Approximate Number System (ANS) that supports an intuitive sense of numerical quantity. Previous work in both children and adults suggests that individual differences in the precision of ANS representations correlate with symbolic math performance. However, this work has been almost entirely correlational in nature. Here we tested for a causal link between ANS precision and symbolic math performance by asking whether a temporary modulation of ANS precision changes symbolic math performance. First we replicated a recent finding that 5-year-old children make more precise ANS discriminations when starting with easier trials and gradually progressing to harder ones, compared to the reverse. Next, we show that this brief modulation of ANS precision influenced children’s performance on a subsequent symbolic math task, but not a vocabulary task. In a supplemental experiment we present evidence that children who performed ANS discriminations in a random trial order showed intermediate performance both on the ANS task and the symbolic math task, compared to the children who made ordered discriminations. Thus, our results point to a specific causal link from the ANS to symbolic math performance. PMID:27061668

  4. The Role of Occupational Complexity in Trajectories of Cognitive Aging Before and After Retirement

    PubMed Central

    Finkel, Deborah; Andel, Ross; Gatz, Margaret; Pedersen, Nancy L.

    2009-01-01

    We examined the association between complexity of the main lifetime occupation and changes in cognitive ability in later life. Data on complexity of work with data, people, and things and on four cognitive factors (verbal, spatial, memory, and speed) were available from 462 individuals in the longitudinal Swedish Adoption/Twin Study of Aging. Mean age at the first measurement wave was 64.3 (s.d. = 7.2) and 65% of the sample had at least 3 waves of data. Occupational complexity with people and data were both correlated with cognitive performance. Individuals with more complex work demonstrated higher mean performance on the verbal, spatial, and speed factors. Latent growth curve analyses indicated that, after correcting for education, only complexity with people was associated with differences in cognitive performance and rate of cognitive change. Continued engagement as a result of occupational complexity with people helped to facilitate verbal function before retirement, while a previous high level of complexity of work with people was associated with faster decline after retirement on the spatial factor. PMID:19739912

  5. The Influence of Grain Refiners on the Efficiency of Ceramic Foam Filters

    NASA Astrophysics Data System (ADS)

    Towsey, Nicholas; Schneider, Wolfgang; Krug, Hans-Peter; Hardman, Angela; Keegan, Neil J.

    An extensive program of work has been carried out to evaluate the efficiency of ceramic foam filters under carefully controlled conditions. Work reported at previous TMS meetings showed that in the absence of grain refiners, ceramic foam filters have the capacity for high filtration efficiency and consistent, reliable performance. The current phase of the investigation focuses on the impact grain refiner additions have on filter performance. The high filtration efficiencies obtained using 50 or 80ppi CFF's in the absence of grain refiners diminish when Al-3%Ti-1%B grain refiners are added. This, together with the impact of incoming inclusion loading on filter performance and the level of grain refiner addition are considered in detail. The new generation Al-3%Ti-0.15%C grain refiner has also been included. At typical addition levels (1kg/tonne) the effect on filter efficiency is similar to that for TiB2based grain refiners. The work was again conducted on a production scale using AA1050 alloy. Metal quality was determined using LiMCA and PoDFA. Spent filters were also analysed.

  6. A treatment program for individuals with deficient evaluative processing and consequent impaired social and risk judgement.

    PubMed

    Park, Norman W; Conrod, Brian; Hussain, Zahra; Murphy, Kelly J; Rewilak, Dmytro; Black, Sandra E

    2003-01-01

    The current study evaluated the effectiveness of a rehabilitation program developed to assist individuals such as AM who have impaired social and risk judgement. AM's difficulties developed after a severe traumatic brain injury that resulted in bilateral frontal and temporal lobe damage including damage to the amygdala. Previous work (Park et al., 2001) established that AM had impaired automatic processing of negative, but not positive evaluative information, and relatively spared processing of both types of evaluative information when using controlled or strategic processing. In the Strategic Evaluation of Alternatives (SEA) treatment program, AM was trained to compensate for his impairments by explicitly retrieving positive and negative attributes associated with potential actions prior to performing them. The SEA treatment focused specifically on improving AM's ability to obtain financial compensation for his work-related activities. Results showed improved performance on work-related activities and evidence of generalization. Analyses suggested that the process underlying improved performance was compensatory rather than restorative in nature. We discuss the implications of these results for the development of rehabilitation treatment for patients with impaired social and risk judgement.

  7. Designing synthetic networks in silico: a generalised evolutionary algorithm approach.

    PubMed

    Smith, Robert W; van Sluijs, Bob; Fleck, Christian

    2017-12-02

    Evolution has led to the development of biological networks that are shaped by environmental signals. Elucidating, understanding and then reconstructing important network motifs is one of the principal aims of Systems & Synthetic Biology. Consequently, previous research has focused on finding optimal network structures and reaction rates that respond to pulses or produce stable oscillations. In this work we present a generalised in silico evolutionary algorithm that simultaneously finds network structures and reaction rates (genotypes) that can satisfy multiple defined objectives (phenotypes). The key step to our approach is to translate a schema/binary-based description of biological networks into systems of ordinary differential equations (ODEs). The ODEs can then be solved numerically to provide dynamic information about an evolved networks functionality. Initially we benchmark algorithm performance by finding optimal networks that can recapitulate concentration time-series data and perform parameter optimisation on oscillatory dynamics of the Repressilator. We go on to show the utility of our algorithm by finding new designs for robust synthetic oscillators, and by performing multi-objective optimisation to find a set of oscillators and feed-forward loops that are optimal at balancing different system properties. In sum, our results not only confirm and build on previous observations but we also provide new designs of synthetic oscillators for experimental construction. In this work we have presented and tested an evolutionary algorithm that can design a biological network to produce desired output. Given that previous designs of synthetic networks have been limited to subregions of network- and parameter-space, the use of our evolutionary optimisation algorithm will enable Synthetic Biologists to construct new systems with the potential to display a wider range of complex responses.

  8. Geometric Lagrangian approach to the physical degree of freedom count in field theory

    NASA Astrophysics Data System (ADS)

    Díaz, Bogar; Montesinos, Merced

    2018-05-01

    To circumvent some technical difficulties faced by the geometric Lagrangian approach to the physical degree of freedom count presented in the work of Díaz, Higuita, and Montesinos [J. Math. Phys. 55, 122901 (2014)] that prevent its direct implementation to field theory, in this paper, we slightly modify the geometric Lagrangian approach in such a way that its resulting version works perfectly for field theory (and for particle systems, of course). As in previous work, the current approach also allows us to directly get the Lagrangian constraints, a new Lagrangian formula for the counting of the number of physical degrees of freedom, the gauge transformations, and the number of first- and second-class constraints for any action principle based on a Lagrangian depending on the fields and their first derivatives without performing any Dirac's canonical analysis. An advantage of this approach over the previous work is that it also allows us to handle the reducibility of the constraints and to get the off-shell gauge transformations. The theoretical framework is illustrated in 3-dimensional generalized general relativity (Palatini and Witten's exotic actions), Chern-Simons theory, 4-dimensional BF theory, and 4-dimensional general relativity given by Palatini's action with a cosmological constant.

  9. Influence of psoriasis on work.

    PubMed

    Mattila, Kalle; Leino, Mauri; Mustonen, Anssi; Koulu, Leena; Tuominen, Risto

    2013-04-01

    Previous research indicates that psoriasis has an impact on early retirement, sick leave days and reduced work performance. To evaluate the disadvantages at work caused by psoriasis. The sample was based on patients visiting the dermatology outpatient clinic in Turku University Hospital. 262 returned a mailed questionnaire. The subjects were asked how many hours they were on a sick leave (absenteeism) and working while sick (presenteeism) due to psoriasis and other health reasons. Of the retired, 17.0% felt they were retired due to psoriasis. Those in the active work force reported on average 4.5 hours absenteeism and 8.3 hours of presenteeism due to psoriasis during the last 4 weeks. Psoriasis caused 27.0% of the total absenteeism and 39.0% of presenteeism. More than a quarter (28.9%) had been forced to modify their work due to psoriasis, most frequently to make the work less irritating for the skin. Psoriasis has a negative effect on patients' work in many ways, causing early retirement from work, sick leave days, change of occupation and work modifications.

  10. The Workplace Experiences of Women with Fibromyalgia.

    PubMed

    Juuso, Päivi; Skär, Lisa; Sundin, Karin; Söderberg, Siv

    2016-06-01

    Fibromyalgia (FM) is a common pain syndrome that mostly affects women. Chronic pain and other symptoms often chalenge work for women with FM. This study aimed to explore how women with FM experience their work situations. A purposive sample of 15 women with FM was interviewed with in-depth qualitative interviews. Data were analysed using a hermeneutic approach. The results revealed that women with FM experienced incapacity to work as they had previously and eventually accepted that their work life had changed or reached its end. Since their work had great significance in their lives, feelings of loss and sorrow were common. Women who were working, unemployed, or on sick leave described feelings of fear for their future work situations. Women with FM greatly value their work. Their wish to perform work as before is however, not consistent with their abilities. As such, women with FM need support in continuing to work for as long as possible, after which they need support in finding new values in life. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Six degree-of-freedom analysis of hip, knee, ankle and foot provides updated understanding of biomechanical work during human walking.

    PubMed

    Zelik, Karl E; Takahashi, Kota Z; Sawicki, Gregory S

    2015-03-01

    Measuring biomechanical work performed by humans and other animals is critical for understanding muscle-tendon function, joint-specific contributions and energy-saving mechanisms during locomotion. Inverse dynamics is often employed to estimate joint-level contributions, and deformable body estimates can be used to study work performed by the foot. We recently discovered that these commonly used experimental estimates fail to explain whole-body energy changes observed during human walking. By re-analyzing previously published data, we found that about 25% (8 J) of total positive energy changes of/about the body's center-of-mass and >30% of the energy changes during the Push-off phase of walking were not explained by conventional joint- and segment-level work estimates, exposing a gap in our fundamental understanding of work production during gait. Here, we present a novel Energy-Accounting analysis that integrates various empirical measures of work and energy to elucidate the source of unexplained biomechanical work. We discovered that by extending conventional 3 degree-of-freedom (DOF) inverse dynamics (estimating rotational work about joints) to 6DOF (rotational and translational) analysis of the hip, knee, ankle and foot, we could fully explain the missing positive work. This revealed that Push-off work performed about the hip may be >50% greater than conventionally estimated (9.3 versus 6.0 J, P=0.0002, at 1.4 m s(-1)). Our findings demonstrate that 6DOF analysis (of hip-knee-ankle-foot) better captures energy changes of the body than more conventional 3DOF estimates. These findings refine our fundamental understanding of how work is distributed within the body, which has implications for assistive technology, biomechanical simulations and potentially clinical treatment. © 2015. Published by The Company of Biologists Ltd.

  12. Directed Forgetting and Directed Remembering in Visual Working Memory

    PubMed Central

    Williams, Melonie; Woodman, Geoffrey F.

    2013-01-01

    A defining characteristic of visual working memory is its limited capacity. This means that it is crucial to maintain only the most relevant information in visual working memory. However, empirical research is mixed as to whether it is possible to selectively maintain a subset of the information previously encoded into visual working memory. Here we examined the ability of subjects to use cues to either forget or remember a subset of the information already stored in visual working memory. In Experiment 1, participants were cued to either forget or remember one of two groups of colored squares during a change-detection task. We found that both types of cues aided performance in the visual working memory task, but that observers benefited more from a cue to remember than a cue to forget a subset of the objects. In Experiment 2, we show that the previous findings, which indicated that directed-forgetting cues are ineffective, were likely due to the presence of invalid cues that appear to cause observers to disregard such cues as unreliable. In Experiment 3, we recorded event-related potentials (ERPs) and show that an electrophysiological index of focused maintenance is elicited by cues that indicate which subset of information in visual working memory needs to be remembered, ruling out alternative explanations of the behavioral effects of retention-interval cues. The present findings demonstrate that observers can focus maintenance mechanisms on specific objects in visual working memory based on cues indicating future task relevance. PMID:22409182

  13. Teaching Rational Number Addition Using Video Games: The Effects of Instructional Variation. CRESST Report 808

    ERIC Educational Resources Information Center

    Vendlinski, Terry P.; Chung, Greg K. W. K.; Binning, Kevin R.; Buschang, Rebecca E.

    2011-01-01

    Understanding the meaning of rational numbers and how to perform mathematical operations with those numbers seems to be a perennial problem in the United States for both adults and children. Based on previous work, we hypothesized that giving students more time to practice using rational numbers in an environment that enticed them to apply their…

  14. The Performance of Left-Handed Participants on a Preferential Reaching Test

    ERIC Educational Resources Information Center

    Mamolo, Carla M.; Roy, Eric A.; Bryden, Pamela J.; Rohr, Linda E.

    2005-01-01

    Previous research in our laboratory has examined the distribution of preferred hand (PH) reaches in working space with right-handed participants. In one study, we examined the effects of tool position and task demands on the frequency of PH reaches with right-handers (Mamolo, Roy, Bryden, & Rohr, 2004). We found that PH reaches were at a maximum…

  15. Developmental Profiles for Multiple Object Tracking and Spatial Memory: Typically Developing Preschoolers and People with Williams Syndrome

    ERIC Educational Resources Information Center

    O'Hearn, Kirsten; Hoffman, James E.; Landau, Barbara

    2010-01-01

    The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory…

  16. Performers and Postulates: The Role of Evolving Socio-Historical Contexts in Shaping New Teacher Professional Identities

    ERIC Educational Resources Information Center

    Leonard, Simon N.; Roberts, Philip

    2014-01-01

    In this article we investigate the generative causes of variation in the professional identity of new teachers. Building on previous work that has shown a link between professional identity and socio-political context, we argue that the context experienced in late adolescence and early adulthood is particularly significant in shaping how beginning…

  17. Who Do You Think I Am? Modeling Individual Differences for More Adaptive and Effective Instruction

    ERIC Educational Resources Information Center

    Allen, Laura K.

    2015-01-01

    The purpose of intelligent tutoring systems is to provide students with personalized instruction and feedback. The focus of these systems typically rests in the adaptability of the feedback provided to students, which relies on automated assessments of performance in the system. A large focus of my previous work has been to determine how natural…

  18. Reversible Hippocampal Lesions Disrupt Water Maze Performance during Both Recent and Remote Memory Tests

    ERIC Educational Resources Information Center

    Broadbent, Nicola J.; Squire, Larry R.; Clark, Robert E.

    2006-01-01

    Conventional lesion methods have shown that damage to the rodent hippocampus can impair previously acquired spatial memory in tasks such as the water maze. In contrast, work with reversible lesion methods using a different spatial task has found remote memory to be spared. To determine whether the finding of spared remote spatial memory depends on…

  19. Modeling hazardous fire potential within a completed fuel treatment network in the northern Sierra Nevada

    Treesearch

    Brandon M. Collins; Heather A. Kramer; Kurt Menning; Colin Dillingham; David Saah; Peter A. Stine; Scott L. Stephens

    2013-01-01

    We built on previous work by performing a more in-depth examination of a completed landscape fuel treatment network. Our specific objectives were: (1) model hazardous fire potential with and without the treatment network, (2) project hazardous fire potential over several decades to assess fuel treatment network longevity, and (3) assess fuel treatment effectiveness and...

  20. A Latent Variable Approach to Determining the Structure of Executive Function in Preschool Children

    ERIC Educational Resources Information Center

    Miller, Michael R.; Giesbrecht, Gerald F.; Muller, Ulrich; McInerney, Robert J.; Kerns, Kimberly A.

    2012-01-01

    The composition of executive function (EF) in preschool children was examined using confirmatory factor analysis (CFA). A sample of 129 children between 3 and 5 years of age completed a battery of EF tasks. Using performance indicators of working memory and inhibition similar to previous CFA studies with preschoolers, we replicated a unitary EF…

  1. Study of the $$\\beta $$ Decay of Fission Products with the DTAS Detector

    DOE PAGES

    Guadilla, V.; Algora, A.; Tain, J. L.; ...

    2017-01-01

    Total Absorption Spectroscopy measurements of the β decay of 103Mo and 103Tc, important contributors to the decay heat summation calculation in reactors, are reported in this work. Furthermore, the analysis of the experiment, performed at IGISOL with the new DTAS detector, show new β intensity that was not detected in previous measurements with Ge detectors.

  2. Unimpaired Perception of Social and Physical Causality, but Impaired Perception of Animacy in High Functioning Children with Autism

    ERIC Educational Resources Information Center

    Congiu, Sara; Schlottmann, Anne; Ray, Elizabeth

    2010-01-01

    We investigated perception of social and physical causality and animacy in simple motion events, for high-functioning children with autism (CA = 13, VMA = 9.6). Children matched 14 different animations to pictures showing physical, social or non-causality. In contrast to previous work, children with autism performed at a high level similar to…

  3. Reducing dietary protein in pond production of hybrid striped bass - study shows a significant reduction is possible in digestible protein level in commercial diets

    USDA-ARS?s Scientific Manuscript database

    In previous work, we demonstrated that diets containing 40% digestible protein (DP) (45% crude protein) and 18 %lipid supplemented with Met and Lys resulted in superior performance and nutrient retentions in hybrid striped bass compared to less energy-dense diets when rearing hybrid striped bass at ...

  4. Modelling a C-Band Space Surveillance Radar using Systems Tool Kit

    DTIC Science & Technology

    2013-02-01

    directly) or ‘Calculate’ by selecting to use: Earth, Sun, Atmosphere, Rain, Clouds & Fog, Tropo Scintillation, and/or Cosmic Background noise in the...OVERVIEW OF THE RADAR.......................................................................................... 2 2.1 Background ...performance described in previous work [1]. UNCLASSIFIED 1 UNCLASSIFIED DSTO-TN-1164 2. Overview of the Radar 2.1 Background The AN/FPQ-14 is a

  5. New approaches for measuring changes in the cortical surface using an automatic reconstruction algorithm

    NASA Astrophysics Data System (ADS)

    Pham, Dzung L.; Han, Xiao; Rettmann, Maryam E.; Xu, Chenyang; Tosun, Duygu; Resnick, Susan; Prince, Jerry L.

    2002-05-01

    In previous work, the authors presented a multi-stage procedure for the semi-automatic reconstruction of the cerebral cortex from magnetic resonance images. This method suffered from several disadvantages. First, the tissue classification algorithm used can be sensitive to noise within the image. Second, manual interaction was required for masking out undesired regions of the brain image, such as the ventricles and putamen. Third, iterated median filters were used to perform a topology correction on the initial cortical surface, resulting in an overly smoothed initial surface. Finally, the deformable surface used to converge to the cortex had difficulty capturing narrow gyri. In this work, all four disadvantages of the procedure have been addressed. A more robust tissue classification algorithm is employed and the manual masking step is replaced by an automatic method involving level set deformable models. Instead of iterated median filters, an algorithm developed specifically for topology correction is used. The last disadvantage is addressed using an algorithm that artificially separates adjacent sulcal banks. The new procedure is more automated but also more accurate than the previous one. Its utility is demonstrated by performing a preliminary study on data from the Baltimore Longitudinal Study of Aging.

  6. Attention-deficit/hyperactivity disorder and phonological working memory: Methodological variability affects clinical and experimental performance metrics.

    PubMed

    Tarle, Stephanie J; Alderson, R Matt; Patros, Connor H G; Lea, Sarah E; Hudec, Kristen L; Arrington, Elaine F

    2017-05-01

    Despite promising findings in extant research that suggest impaired working memory (WM) serves as a central neurocognitive deficit or candidate endophenotype of attention-deficit/hyperactivity disorder (ADHD), findings from translational research have been relatively underwhelming. This study aimed to explicate previous equivocal findings by systematically examining the effect of methodological variability on WM performance estimates across experimental and clinical WM measures. Age-matched boys (ages 8-12 years) with (n = 20) and without (n = 20) ADHD completed 1 experimental (phonological) and 2 clinical (digit span, letter-number sequencing) WM measures. The use of partial scoring procedures, administration of greater trial numbers, and high central executive demands yielded moderate-to-large between-groups effect sizes. Moreover, the combination of these best-case procedures, compared to worst-case procedures (i.e., absolute scoring, administration of few trials, use of discontinue rules, and low central executive demands), resulted in a 12.5% increase in correct group classification. Collectively, these findings explain inconsistent ADHD-related WM deficits in previous reports, and highlight the need for revised clinical measures that utilize best-case procedures. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  7. Optimal Wonderful Life Utility Functions in Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.; Tumer, Kagan; Swanson, Keith (Technical Monitor)

    2000-01-01

    The mathematics of Collective Intelligence (COINs) is concerned with the design of multi-agent systems so as to optimize an overall global utility function when those systems lack centralized communication and control. Typically in COINs each agent runs a distinct Reinforcement Learning (RL) algorithm, so that much of the design problem reduces to how best to initialize/update each agent's private utility function, as far as the ensuing value of the global utility is concerned. Traditional team game solutions to this problem assign to each agent the global utility as its private utility function. In previous work we used the COIN framework to derive the alternative Wonderful Life Utility (WLU), and experimentally established that having the agents use it induces global utility performance up to orders of magnitude superior to that induced by use of the team game utility. The WLU has a free parameter (the clamping parameter) which we simply set to zero in that previous work. Here we derive the optimal value of the clamping parameter, and demonstrate experimentally that using that optimal value can result in significantly improved performance over that of clamping to zero, over and above the improvement beyond traditional approaches.

  8. Pre-configured polyhedron based protection against multi-link failures in optical mesh networks.

    PubMed

    Huang, Shanguo; Guo, Bingli; Li, Xin; Zhang, Jie; Zhao, Yongli; Gu, Wanyi

    2014-02-10

    This paper focuses on random multi-link failures protection in optical mesh networks, instead of single, the dual or sequential failures of previous studies. Spare resource efficiency and failure robustness are major concerns in link protection strategy designing and a k-regular and k-edge connected structure is proved to be one of the optimal solutions for link protection network. Based on this, a novel pre-configured polyhedron based protection structure is proposed, and it could provide protection for both simultaneous and sequential random link failures with improved spare resource efficiency. Its performance is evaluated in terms of spare resource consumption, recovery rate and average recovery path length, as well as compared with ring based and subgraph protection under probabilistic link failure scenarios. Results show the proposed novel link protection approach has better performance than previous works.

  9. A case-crossover study of transient risk factors influence on occupational injuries: a study protocol based on a review of previous studies.

    PubMed

    Oesterlund, Anna H; Lander, Flemming; Lauritsen, Jens

    2016-10-01

    The occupational injury incident rate remains relatively high in the European Union. The case-crossover study gives a unique opportunity to study transient risk factors that normally would be very difficult to approach. Studies like this have been carried out in both America and Asia, but so far no relevant research has been conducted in Europe. Case-crossover studies of occupational injuries were collected from PubMed and Embase and read through. Previous experiences concerning method, exposure and outcome, time-related measurements and construction of the questionnaire were taken into account in the preparation of a pilot study. Consequently, experiences from the pilot study were used to design the study protocol. Approximately 2000 patients with an occupational injury will be recruited from the emergency departments in Herning and Odense, Denmark. A standardised questionnaire will be used to collect basic demographic data and information on eight transient risk factors. Based on previous studies and knowledge on occupational injuries the transient risk factors we chose to examine were: time pressure, performing a task with a different method/using unaccustomed technique, change in working surroundings, using a phone, disagreement, feeling ill, being distracted and using malfunctioning machinery/tools or work material. Exposure time 'just before the injury' will be compared with two control periods, 'previous day at the same time of the injury' (pair match) and the previous work week (usual frequency). This study protocol describes a unique opportunity to calculate the effect of transient risk factors on occupational injuries in a European setting. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  10. Automated social skills training with audiovisual information.

    PubMed

    Tanaka, Hiroki; Sakti, Sakriani; Neubig, Graham; Negoro, Hideki; Iwasaka, Hidemi; Nakamura, Satoshi

    2016-08-01

    People with social communication difficulties tend to have superior skills using computers, and as a result computer-based social skills training systems are flourishing. Social skills training, performed by human trainers, is a well-established method to obtain appropriate skills in social interaction. Previous works have attempted to automate one or several parts of social skills training through human-computer interaction. However, while previous work on simulating social skills training considered only acoustic and linguistic features, human social skills trainers take into account visual features (e.g. facial expression, posture). In this paper, we create and evaluate a social skills training system that closes this gap by considering audiovisual features regarding ratio of smiling, yaw, and pitch. An experimental evaluation measures the difference in effectiveness of social skill training when using audio features and audiovisual features. Results showed that the visual features were effective to improve users' social skills.

  11. Thyroid-specific questions on work ability showed known-groups validity among Danes with thyroid diseases.

    PubMed

    Nexo, Mette Andersen; Watt, Torquil; Bonnema, Steen Joop; Hegedüs, Laszlo; Rasmussen, Åse Krogh; Feldt-Rasmussen, Ulla; Bjorner, Jakob Bue

    2015-07-01

    We aimed to identify the best approach to work ability assessment in patients with thyroid disease by evaluating the factor structure, measurement equivalence, known-groups validity, and predictive validity of a broad set of work ability items. Based on the literature and interviews with thyroid patients, 24 work ability items were selected from previous questionnaires, revised, or developed anew. Items were tested among 632 patients with thyroid disease (non-toxic goiter, toxic nodular goiter, Graves' disease (with or without orbitopathy), autoimmune hypothyroidism, and other thyroid diseases), 391 of which had participated in a study 5 years previously. Responses to select items were compared to general population data. We used confirmatory factor analyses for categorical data, logistic regression analyses and tests of differential item function, and head-to-head comparisons of relative validity in distinguishing known groups. Although all work ability items loaded on a common factor, the optimal factor solution included five factors: role physical, role emotional, thyroid-specific limitations, work limitations (without disease attribution), and work performance. The scale on thyroid-specific limitations showed the most power in distinguishing clinical groups and time since diagnosis. A global single item proved useful for comparisons with the general population, and a thyroid-specific item predicted labor market exclusion within the next 5 years (OR 5.0, 95 % CI 2.7-9.1). Items on work limitations with attribution to thyroid disease were most effective in detecting impact on work ability and showed good predictive validity. Generic work ability items remain useful for general population comparisons.

  12. Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Barreira Luz, R. J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Chavez, A. G.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; D'Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; Deligny, O.; Di Giulio, C.; Di Matteo, A.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D'Olivo, J. C.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fick, B.; Figueira, J. M.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; Gaior, R.; García, B.; Garcia-Pinto, D.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kemp, J.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; LaHurd, D.; Lauscher, M.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Mockler, D.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Müller, A. L.; Müller, G.; Muller, M. A.; Müller, S.; Mussa, R.; Naranjo, I.; Nellen, L.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, H.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perlín, M.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollan, R.; Rautenberg, J.; Ravignani, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rogozin, D.; Roncoroni, M. J.; Roth, M.; Roulet, E.; Rovero, A. C.; Ruehl, P.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarmento, R.; Sarmiento, C. A.; Sato, R.; Schauer, M.; Scherini, V.; Schieler, H.; Schimp, M.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Strafella, F.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Swain, J.; Szadkowski, Z.; Taboada, A.; Taborda, O. A.; Tapia, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Torralba Elipe, G.; Torri, M.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Yang, L.; Yelos, D.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

    2017-06-01

    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80o and energies in excess of 4 EeV (4 × 1018 eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding p-values obtained after accounting for searches blindly performed at several angular scales, are 1.3 × 10-5 in the case of the angular power spectrum, and 2.5 × 10-3 in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.

  13. Exploratory data analysis of acceleration signals to select light-weight and accurate features for real-time activity recognition on smartphones.

    PubMed

    Khan, Adil Mehmood; Siddiqi, Muhammad Hameed; Lee, Seok-Won

    2013-09-27

    Smartphone-based activity recognition (SP-AR) recognizes users' activities using the embedded accelerometer sensor. Only a small number of previous works can be classified as online systems, i.e., the whole process (pre-processing, feature extraction, and classification) is performed on the device. Most of these online systems use either a high sampling rate (SR) or long data-window (DW) to achieve high accuracy, resulting in short battery life or delayed system response, respectively. This paper introduces a real-time/online SP-AR system that solves this problem. Exploratory data analysis was performed on acceleration signals of 6 activities, collected from 30 subjects, to show that these signals are generated by an autoregressive (AR) process, and an accurate AR-model in this case can be built using a low SR (20 Hz) and a small DW (3 s). The high within class variance resulting from placing the phone at different positions was reduced using kernel discriminant analysis to achieve position-independent recognition. Neural networks were used as classifiers. Unlike previous works, true subject-independent evaluation was performed, where 10 new subjects evaluated the system at their homes for 1 week. The results show that our features outperformed three commonly used features by 40% in terms of accuracy for the given SR and DW.

  14. Computational identification of promising thermoelectric materials among known quasi-2D binary compounds

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

    Gorai, Prashun; Toberer, Eric S.; Stevanović, Vladan

    Quasi low-dimensional structures are abundant among known thermoelectric materials, primarily because of their low lattice thermal conductivities. In this work, we have computationally assessed the potential of 427 known binary quasi-2D structures in 272 different chemistries for thermoelectric performance. To assess the thermoelectric performance, we employ an improved version of our previously developed descriptor for thermoelectric performance [Yan et al., Energy Environ. Sci., 2015, 8, 983]. The improvement is in the explicit treatment of van der Waals interactions in quasi-2D materials, which leads to significantly better predictions of their crystal structures and lattice thermal conductivities. The improved methodology correctly identifiesmore » known binary quasi-2D thermoelectric materials such as Sb2Te3, Bi2Te3, SnSe, SnS, InSe, and In2Se3. As a result, we propose candidate quasi-2D binary materials, a number of which have not been previously considered for thermoelectric applications.« less

  15. Resting state functional connectivity of the anterior striatum and prefrontal cortex predicts reading performance in school-age children.

    PubMed

    Alcauter, Sarael; García-Mondragón, Liliana; Gracia-Tabuenca, Zeus; Moreno, Martha B; Ortiz, Juan J; Barrios, Fernando A

    2017-11-01

    The current study investigated the neural basis of reading performance in 60 school-age Spanish-speaking children, aged 6 to 9years. By using a data-driven approach and an automated matching procedure, we identified a left-lateralized resting state network that included typical language regions (Wernicke's and Broca's regions), prefrontal cortex, pre- and post-central gyri, superior and middle temporal gyri, cerebellum, and subcortical regions, and explored its relevance for reading performance (accuracy, comprehension and speed). Functional connectivity of the left frontal and temporal cortices and subcortical regions predicted reading speed. These results extend previous findings on the relationship between functional connectivity and reading competence in children, providing new evidence about such relationships in previously unexplored regions in the resting brain, including the left caudate, putamen and thalamus. This work highlights the relevance of a broad network, functionally synchronized in the resting state, for the acquisition and perfecting of reading abilities in young children. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Spatial Learning and Wayfinding in an Immersive Environment: The Digital Fulldome.

    PubMed

    Hedge, Craig; Weaver, Ruth; Schnall, Simone

    2017-05-01

    Previous work has examined whether immersive technologies can benefit learning in virtual environments, but the potential benefits of technology in this context are confounded by individual differences such as spatial ability. We assessed spatial knowledge acquisition in male and female participants using a technology not previously examined empirically: the digital fulldome. Our primary aim was to examine whether performance on a test of survey knowledge was better in a fulldome (N = 28, 12 males) relative to a large, flat screen display (N = 27, 13 males). Regression analysis showed that, compared to a flat screen display, males showed higher levels of performance on a test of survey knowledge after learning in the fulldome, but no benefit occurred for females. Furthermore, performance correlated with spatial visualization ability in male participants, but not in female participants. Thus, the digital fulldome is a potentially useful learning aid, capable of accommodating multiple users, but individual differences and use of strategy need to be considered.

  17. Mindful maths: reducing the impact of stereotype threat through a mindfulness exercise.

    PubMed

    Weger, Ulrich W; Hooper, Nic; Meier, Brian P; Hopthrow, Tim

    2012-03-01

    Individuals who experience stereotype threat - the pressure resulting from social comparisons that are perceived as unfavourable - show performance decrements across a wide range of tasks. One account of this effect is that the cognitive pressure triggered by such threat drains the same cognitive (or working-memory) resources that are implicated in the respective task. The present study investigates whether mindfulness can be used to moderate stereotype threat, as mindfulness has previously been shown to alleviate working-memory load. Our results show that performance decrements that typically occur under stereotype threat can indeed be reversed when the individual engages in a brief (5 min) mindfulness task. The theoretical implications of our findings are discussed. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  18. Establishing links between health and productivity in the New Zealand workforce.

    PubMed

    Williden, Micalla; Schofield, Grant; Duncan, Scott

    2012-05-01

    To provide the first investigation of individual health behaviors and measures of work performance in New Zealand. Health risk assessments were completed by 747 adults aged 18 to 65 years. Associations between measures of productivity and health risk factors were assessed using multiple stepwise regression. Participants with low to moderate psychological distress levels and who were physically active reported a work performance 6.5% (P < 0.001) and 3.5% (P < 0.001) higher, respectively. Furthermore, high psychological distress and smoking accounted for 16.8 (P < 0.001) and 11.6 (P = 0.038) additional absentee hours over the previous 4 weeks. The impact that psychological distress, physical inactivity, and smoking have on productivity suggests that employers may benefit from contributing to health promotion within the workplace.

  19. Prevalence and Risk Factors Associated with Musculoskeletal Discomfort in Spay and Neuter Veterinarians.

    PubMed

    White, Sara C

    2013-02-04

    A cross-sectional study to investigate musculoskeletal discomfort (MSD) surveyed 219 veterinarians who currently or previously perform spays and neuters at least 4 hours per week. Participants were asked about the presence and severity of hand and body MSD during the previous month, whether MSD interfered with work or daily activities, whether they attributed their MSD to their spay/neuter work, and whether MSD had ever necessitated absence from work. The period prevalence of MSD was 99.1%, with 76.7% experiencing hand or wrist pain and 98.2% experiencing body pain. Hand discomfort was most commonly reported in the right thumb and/or thumb base (49.8%) and the right wrist (37.9%). Body discomfort was most commonly reported in the lower back (76.7%), shoulders (72.6%), and neck (71.7%). Increasing career length, increasing weekly hours in surgery and decreasing job satisfaction were the work-related factors with the greatest relative contribution accounting for variation in hand pain severity and total pain. Although 94.4% of respondents felt that posture during surgery is important, only 30.6% had received any instruction in posture and positioning for surgery. Future interventions should aim to optimize surgical efficiency, surgeon work schedules, and working environment. Analysis and intervention studies are required to determine further causes of MSD in these veterinarians and develop interventions to prevent MSD.

  20. Electric Ground Support Equipment Advanced Battery Technology Demonstration Project at the Ontario Airport

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

    Tyler Gray; Jeremy Diez; Jeffrey Wishart

    2013-07-01

    The intent of the electric Ground Support Equipment (eGSE) demonstration is to evaluate the day-to-day vehicle performance of electric baggage tractors using two advanced battery technologies to demonstrate possible replacements for the flooded lead-acid (FLA) batteries utilized throughout the industry. These advanced battery technologies have the potential to resolve barriers to the widespread adoption of eGSE deployment. Validation testing had not previously been performed within fleet operations to determine if the performance of current advanced batteries is sufficient to withstand the duty cycle of electric baggage tractors. This report summarizes the work performed and data accumulated during this demonstration inmore » an effort to validate the capabilities of advanced battery technologies. This report summarizes the work performed and data accumulated during this demonstration in an effort to validate the capabilities of advanced battery technologies. The demonstration project also grew the relationship with Southwest Airlines (SWA), our demonstration partner at Ontario International Airport (ONT), located in Ontario, California. The results of this study have encouraged a proposal for a future demonstration project with SWA.« less

  1. Job Performance as Multivariate Dynamic Criteria: Experience Sampling and Multiway Component Analysis.

    PubMed

    Spain, Seth M; Miner, Andrew G; Kroonenberg, Pieter M; Drasgow, Fritz

    2010-08-06

    Questions about the dynamic processes that drive behavior at work have been the focus of increasing attention in recent years. Models describing behavior at work and research on momentary behavior indicate that substantial variation exists within individuals. This article examines the rationale behind this body of work and explores a method of analyzing momentary work behavior using experience sampling methods. The article also examines a previously unused set of methods for analyzing data produced by experience sampling. These methods are known collectively as multiway component analysis. Two archetypal techniques of multimode factor analysis, the Parallel factor analysis and the Tucker3 models, are used to analyze data from Miner, Glomb, and Hulin's (2010) experience sampling study of work behavior. The efficacy of these techniques for analyzing experience sampling data is discussed as are the substantive multimode component models obtained.

  2. Keeping priorities: the role of working memory and selective attention in cognitive aging.

    PubMed

    de Fockert, Jan W

    2005-11-02

    Cognitive aging is associated with impairments to working memory and top-down control in selective attention, two components of cognitive control associated with the frontal lobes. Recent findings indicate that working memory and selective attention may be interdependent, making a better understanding of their involvement in cognitive aging particularly challenging. A paper in a recent issue of Nature Neuroscience has provided evidence that a reduction in the ability to keep a clear distinction between information to be stored in working memory and information that should be ignored and subsequently suppressed is associated with poor working memory performance. These results are in line with previous evidence for a specific age-related impairment in the ability to separate irrelevant from relevant information and may be able to explain a range of age-related cognitive changes.

  3. A corpus of full-text journal articles is a robust evaluation tool for revealing differences in performance of biomedical natural language processing tools

    PubMed Central

    2012-01-01

    Background We introduce the linguistic annotation of a corpus of 97 full-text biomedical publications, known as the Colorado Richly Annotated Full Text (CRAFT) corpus. We further assess the performance of existing tools for performing sentence splitting, tokenization, syntactic parsing, and named entity recognition on this corpus. Results Many biomedical natural language processing systems demonstrated large differences between their previously published results and their performance on the CRAFT corpus when tested with the publicly available models or rule sets. Trainable systems differed widely with respect to their ability to build high-performing models based on this data. Conclusions The finding that some systems were able to train high-performing models based on this corpus is additional evidence, beyond high inter-annotator agreement, that the quality of the CRAFT corpus is high. The overall poor performance of various systems indicates that considerable work needs to be done to enable natural language processing systems to work well when the input is full-text journal articles. The CRAFT corpus provides a valuable resource to the biomedical natural language processing community for evaluation and training of new models for biomedical full text publications. PMID:22901054

  4. Complexity reduction of rate-equations models for two-choice decision-making.

    PubMed

    Carrillo, José Antonio; Cordier, Stéphane; Deco, Gustavo; Mancini, Simona

    2013-01-01

    We are concerned with the complexity reduction of a stochastic system of differential equations governing the dynamics of a neuronal circuit describing a decision-making task. This reduction is based on the slow-fast behavior of the problem and holds on the whole phase space and not only locally around the spontaneous state. Macroscopic quantities, such as performance and reaction times, computed applying this reduction are in agreement with previous works in which the complexity reduction is locally performed at the spontaneous point by means of a Taylor expansion.

  5. Development of Technologies to Utilize Laser Plasma Radiations Sources for Radiation Effects Sciences

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

    Davis, J F

    2007-01-31

    This final report will cover work performed over the period of November 11, 2005 to September 30, 2006 on the contract to develop technologies using laser sources for radiation effects sciences. The report will discuss four topic areas; the laser source experiments on the Gekko Laser at Osaka, Japan, planning for the Charge State Freeze Out experiments to be performed in calendar year 2007, a review of previous xenon gasbags on the LANL Trident laser to provide planning support to the May-June 2007 HELEN experiments.

  6. Enhancing Scheduling Performance for a Wafer Fabrication Factory: The Biobjective Slack-Diversifying Nonlinear Fluctuation-Smoothing Rule

    PubMed Central

    Chen, Toly; Wang, Yu Cheng

    2012-01-01

    A biobjective slack-diversifying nonlinear fluctuation-smoothing rule (biSDNFS) is proposed in the present work to improve the scheduling performance of a wafer fabrication factory. This rule was derived from a one-factor bi-objective nonlinear fluctuation-smoothing rule (1f-biNFS) by dynamically maximizing the standard deviation of the slack, which has been shown to benefit scheduling performance by several previous studies. The efficacy of the biSDNFS was validated with a simulated case; evidence was found to support its effectiveness. We also suggested several directions in which it can be exploited in the future. PMID:23509446

  7. Environmental performance policy indicators for the public sector: the case of the defence sector.

    PubMed

    Ramos, Tomás B; Alves, Inês; Subtil, Rui; Joanaz de Melo, João

    2007-03-01

    The development of environmental performance policy indicators for public services, and in particular for the defence sector, is an emerging issue. Despite a number of recent initiatives there has been little work done in this area, since the other sectors usually focused on are agriculture, transport, industry, tourism and energy. This type of tool can be an important component for environmental performance evaluation at policy level, when integrated in the general performance assessment system of public missions and activities. The main objective of this research was to develop environmental performance policy indicators for the public sector, specifically applied to the defence sector. Previous research included an assessment of the environmental profile, through the evaluation of how environmental management practices have been adopted in this sector and an assessment of environmental aspects and impacts. This paper builds upon that previous research, developing an indicator framework--SEPI--supported by the selection and construction of environmental performance indicators. Another aim is to discuss how the current environmental indicator framework can be integrated into overall performance management. The Portuguese defence sector is presented and the usefulness of this methodology demonstrated. Feasibility and relevancy criteria are applied to evaluate the set of indicators proposed, allowing indicators to be scored and indicators for the policy level to be obtained.

  8. A continuous time-resolved measure decoded from EEG oscillatory activity predicts working memory task performance.

    PubMed

    Astrand, Elaine

    2018-06-01

    Working memory (WM), crucial for successful behavioral performance in most of our everyday activities, holds a central role in goal-directed behavior. As task demands increase, inducing higher WM load, maintaining successful behavioral performance requires the brain to work at the higher end of its capacity. Because it is depending on both external and internal factors, individual WM load likely varies in a continuous fashion. The feasibility to extract such a continuous measure in time that correlates to behavioral performance during a working memory task remains unsolved. Multivariate pattern decoding was used to test whether a decoder constructed from two discrete levels of WM load can generalize to produce a continuous measure that predicts task performance. Specifically, a linear regression with L2-regularization was chosen with input features from EEG oscillatory activity recorded from healthy participants while performing the n-back task, [Formula: see text]. The feasibility to extract a continuous time-resolved measure that correlates positively to trial-by-trial working memory task performance is demonstrated (r  =  0.47, p  <  0.05). It is furthermore shown that this measure allows to predict task performance before action (r  =  0.49, p  <  0.05). We show that the extracted continuous measure enables to study the temporal dynamics of the complex activation pattern of WM encoding during the n-back task. Specifically, temporally precise contributions of different spectral features are observed which extends previous findings of traditional univariate approaches. These results constitute an important contribution towards a wide range of applications in the field of cognitive brain-machine interfaces. Monitoring mental processes related to attention and WM load to reduce the risk of committing errors in high-risk environments could potentially prevent many devastating consequences or using the continuous measure as neurofeedback opens up new possibilities to develop novel rehabilitation techniques for individuals with degraded WM capacity.

  9. A continuous time-resolved measure decoded from EEG oscillatory activity predicts working memory task performance

    NASA Astrophysics Data System (ADS)

    Astrand, Elaine

    2018-06-01

    Objective. Working memory (WM), crucial for successful behavioral performance in most of our everyday activities, holds a central role in goal-directed behavior. As task demands increase, inducing higher WM load, maintaining successful behavioral performance requires the brain to work at the higher end of its capacity. Because it is depending on both external and internal factors, individual WM load likely varies in a continuous fashion. The feasibility to extract such a continuous measure in time that correlates to behavioral performance during a working memory task remains unsolved. Approach. Multivariate pattern decoding was used to test whether a decoder constructed from two discrete levels of WM load can generalize to produce a continuous measure that predicts task performance. Specifically, a linear regression with L2-regularization was chosen with input features from EEG oscillatory activity recorded from healthy participants while performing the n-back task, n\\in [1,2] . Main results. The feasibility to extract a continuous time-resolved measure that correlates positively to trial-by-trial working memory task performance is demonstrated (r  =  0.47, p  <  0.05). It is furthermore shown that this measure allows to predict task performance before action (r  =  0.49, p  <  0.05). We show that the extracted continuous measure enables to study the temporal dynamics of the complex activation pattern of WM encoding during the n-back task. Specifically, temporally precise contributions of different spectral features are observed which extends previous findings of traditional univariate approaches. Significance. These results constitute an important contribution towards a wide range of applications in the field of cognitive brain–machine interfaces. Monitoring mental processes related to attention and WM load to reduce the risk of committing errors in high-risk environments could potentially prevent many devastating consequences or using the continuous measure as neurofeedback opens up new possibilities to develop novel rehabilitation techniques for individuals with degraded WM capacity.

  10. Teaching for All? Teach For America’s Effects across the Distribution of Student Achievement

    PubMed Central

    Penner, Emily K.

    2016-01-01

    This paper examines the effect of Teach For America (TFA) on the distribution of student achievement in elementary school. It extends previous research by estimating quantile treatment effects (QTE) to examine how student achievement in TFA and non-TFA classrooms differs across the broader distribution of student achievement. It also updates prior distributional work on TFA by correcting for previously unidentified missing data and estimating unconditional, rather than conditional QTE. Consistent with previous findings, results reveal a positive impact of TFA teachers across the distribution of math achievement. In reading, however, relative to veteran non-TFA teachers, students at the bottom of the reading distribution score worse in TFA classrooms, and students in the upper half of the distribution perform better. PMID:27668032

  11. Preliminary analysis of compound systems based on high temperature fuel cell, gas turbine and Organic Rankine Cycle

    NASA Astrophysics Data System (ADS)

    Sánchez, D.; Muñoz de Escalona, J. M.; Monje, B.; Chacartegui, R.; Sánchez, T.

    This article presents a novel proposal for complex hybrid systems comprising high temperature fuel cells and thermal engines. In this case, the system is composed by a molten carbonate fuel cell with cascaded hot air turbine and Organic Rankine Cycle (ORC), a layout that is based on subsequent waste heat recovery for additional power production. The work will credit that it is possible to achieve 60% efficiency even if the fuel cell operates at atmospheric pressure. The first part of the analysis focuses on selecting the working fluid of the Organic Rankine Cycle. After a thermodynamic optimisation, toluene turns out to be the most efficient fluid in terms of cycle performance. However, it is also detected that the performance of the heat recovery vapour generator is equally important, what makes R245fa be the most interesting fluid due to its balanced thermal and HRVG efficiencies that yield the highest global bottoming cycle efficiency. When this fluid is employed in the compound system, conservative operating conditions permit achieving 60% global system efficiency, therefore accomplishing the initial objective set up in the work. A simultaneous optimisation of gas turbine (pressure ratio) and ORC (live vapour pressure) is then presented, to check if the previous results are improved or if the fluid of choice must be replaced. Eventually, even if system performance improves for some fluids, it is concluded that (i) R245fa is the most efficient fluid and (ii) the operating conditions considered in the previous analysis are still valid. The work concludes with an assessment about safety-related aspects of using hydrocarbons in the system. Flammability is studied, showing that R245fa is the most interesting fluid also in this regard due to its inert behaviour, as opposed to the other fluids under consideration all of which are highly flammable.

  12. FINAL REPORT INTEGRATED DM1200 MELTER TESTING USING AZ 102 AND C 106/AY-102 HLW SIMULANTS: HLW SIMULANT VERIFICATION VSL-05R5800-1 REV 0 6/27/05

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

    KRUGER AA; MATLACK KS; GONG W

    2011-12-29

    The principal objectives of the DM1200 melter tests were to determine the effects of feed rheology, feed solid content, and bubbler configuration on glass production rate and off-gas system performance while processing the HLW AZ-101 and C-106/AY-102 feed compositions; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components, as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table. The datamore » provided in this Final Report address the impacts of HLW melter feed rheology on melter throughput and validation of the simulated HLW melter feeds. The primary purpose of this testing is to further validate/verify the HLW melter simulants that have been used for previous melter testing and to support their continued use in developing melter and off-gas related processing information for the Project. The primary simulant property in question is rheology. Simulants and melter feeds used in all previous melter tests were produced by direct addition of chemicals; these feed tend to be less viscous than rheological the upper-bound feeds made from actual wastes. Data provided here compare melter processing for the melter feed used in all previous DM100 and DM1200 tests (nominal melter feed) with feed adjusted by the feed vendor (NOAH Technologies) to be more viscous, thereby simulating more closely the upperbounding feed produced from actual waste. This report provides results of tests that are described in the Test Plan for this work. The Test Plan is responsive to one of several test objectives covered in the WTP Test Specification for this work; consequently, only part of the scope described in the Test Specification was addressed in this particular Test Plan. For the purpose of comparison, the tests reported here were performed with AZ-102 and C-106/AY-102 HLW simulants and glass compositions that are essentially the same as those used for recent DM1200 tests. One exception was the use of an alternate, higher-waste-loading C-106/AY-102 glass composition that was used in previous DM100 tests to further evaluate the performance of the optimized bubbler configuration.« less

  13. The Role of Cognitive Load in Intentional Forgetting Using the Think/No-Think Task.

    PubMed

    Noreen, Saima; de Fockert, Jan W

    2017-01-01

    We investigated the role of cognitive control in intentional forgetting by manipulating working memory load during the think/no-think task. In two experiments, participants learned a series of cue-target word pairs and were asked to recall the target words associated with some cues or to avoid thinking about the target associated with other cues. In addition to this, participants also performed a modified version of the n-back task which required them to respond to the identity of a single target letter present in the currently presented cue word (n = 0 condition, low working memory load), and in either the previous cue word (n = 1 condition, high working memory load, Experiment 1) or the cue word presented two trials previously (n = 2 condition, high working memory load, Experiment 2). Participants' memory for the target words was subsequently tested using same and novel independent probes. In both experiments it was found that although participants were successful at forgetting on both the same and independent-probe tests in the low working memory load condition, they were only successful at forgetting on the same-probe test in the high working memory load condition. We argue that our findings suggest that the high load working memory task diverted attention from direct suppression and acted as an interference-based strategy. Thus, when cognitive resources are limited participants can switch between the strategies they use to prevent unwanted memories from coming to mind.

  14. Talking Physics: Two Case Studies on Short Answers and Self-explanation in Learning Physics

    NASA Astrophysics Data System (ADS)

    Badeau, Ryan C.

    This thesis explores two case studies into the use of short answers and self-explanation to improve student learning in physics. The first set of experiments focuses on the role of short answer questions in the context of computer-based instruction. Through a series of six experiments, we compare and evaluate the performance of computer-assessed short answer questions versus multiple choice for training conceptual topics in physics, controlling for feedback between the two formats. In addition to finding overall similar improvements on subsequent student performance and retention, we identify unique differences in how students interact with the treatments in terms of time spent on feedback and performance on follow-up short answer assessment. In addition, we identify interactions between the level of interactivity of the training, question format, and student attitudinal ratings of each respective training. The second case study focuses on the use of worked examples in the context of multi-concept physics problems - which we call "synthesis problems." For this part of the thesis, four experiments were designed to evaluate the effectiveness of two instructional methods employing worked examples on student performance with synthesis problems; these instructional techniques, analogical comparison and self-explanation, have previously been studied primarily in the context of single-concept problems. As such, the work presented here represents a novel focus on extending these two techniques to this class of more complicated physics problem. Across the four experiments, both self-explanation and certain kinds of analogical comparison of worked examples significantly improved student performance on a target synthesis problem, with distinct improvements in recognition of the relevant concepts. More specifically, analogical comparison significantly improved student performance when the comparisons were invoked between worked synthesis examples. In contrast, similar comparisons between corresponding pairs of worked single-concept examples did not significantly improve performance. On a more complicated synthesis problem, self-explanation was significantly more effective than analogical comparison, potentially due to differences in how successfully students encoded the full structure of the worked examples. Finally, we find that the two techniques can be combined for additional benefit, with the trade-off of slightly more time-on-task.

  15. CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen

    NASA Astrophysics Data System (ADS)

    Chadwick, M. B.; Capote, R.; Trkov, A.; Herman, M. W.; Brown, D. A.; Hale, G. M.; Kahler, A. C.; Talou, P.; Plompen, A. J.; Schillebeeckx, P.; Pigni, M. T.; Leal, L.; Danon, Y.; Carlson, A. D.; Romain, P.; Morillon, B.; Bauge, E.; Hambsch, F.-J.; Kopecky, S.; Giorginis, G.; Kawano, T.; Lestone, J.; Neudecker, D.; Rising, M.; Paris, M.; Nobre, G. P. A.; Arcilla, R.; Cabellos, O.; Hill, I.; Dupont, E.; Koning, A. J.; Cano-Ott, D.; Mendoza, E.; Balibrea, J.; Paradela, C.; Durán, I.; Qian, J.; Ge, Z.; Liu, T.; Hanlin, L.; Ruan, X.; Haicheng, W.; Sin, M.; Noguere, G.; Bernard, D.; Jacqmin, R.; Bouland, O.; De Saint Jean, C.; Pronyaev, V. G.; Ignatyuk, A. V.; Yokoyama, K.; Ishikawa, M.; Fukahori, T.; Iwamoto, N.; Iwamoto, O.; Kunieda, S.; Lubitz, C. R.; Salvatores, M.; Palmiotti, G.; Kodeli, I.; Kiedrowski, B.; Roubtsov, D.; Thompson, I.; Quaglioni, S.; Kim, H. I.; Lee, Y. O.; Fischer, U.; Simakov, S.; Dunn, M.; Guber, K.; Márquez Damián, J. I.; Cantargi, F.; Sirakov, I.; Otuka, N.; Daskalakis, A.; McDermott, B. J.; van der Marck, S. C.

    2018-02-01

    The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 235,238U, 239Pu, 56Fe, 16O and 1H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform

  16. Operation, Modeling and Analysis of the Reverse Water Gas Shift Process

    NASA Technical Reports Server (NTRS)

    Whitlow, Jonathan E.

    2001-01-01

    The Reverse Water Gas Shift process is a candidate technology for water and oxygen production on Mars under the In-Situ Propellant Production project. This report focuses on the operation and analysis of the Reverse Water Gas Shift (RWGS) process, which has been constructed at Kennedy Space Center. A summary of results from the initial operation of the RWGS, process along with an analysis of these results is included in this report. In addition an evaluation of a material balance model developed from the work performed previously under the summer program is included along with recommendations for further experimental work.

  17. Creep, Fatigue and Environmental Interactions and Their Effect on Crack Growth in Superalloys

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Gabb, T. P.; Ghosn, L. J.; Smith, T.

    2017-01-01

    Complex interactions of creep/fatigue/environment control dwell fatigue crack growth (DFCG) in superalloys. Crack tip stress relaxation during dwells significantly changes the crack driving force and influence DFCG. Linear Elastic Fracture Mechanics, Kmax, parameter unsuitable for correlating DFCG behavior due to extensive visco-plastic deformation. Magnitude of remaining crack tip axial stresses controls DFCG resistance due to the brittle-intergranular nature of the crack growth process. Proposed a new empirical parameter, Ksrf, which incorporates visco-plastic evolution of the magnitude of remaining crack tip stresses. Previous work performed at 704C, extend the work to 760C.

  18. The disruptive effects of methamphetamine on delayed-matching-to-sample performance reflect proactive interference and are reduced by SCH23390.

    PubMed

    Macaskill, Anne C; Harrow, Catherine C; Harper, David N

    2015-01-01

    Different drugs produce different patterns of impairment on delayed matching-to-sample tasks. For example, (+/-)3,4-methylenedioxymethamphetamine (MDMA) produces an increase in proactive interference. That is, subjects are less accurate when they are required to make a response different to the one they made on the immediately previous trial. The current study assessed whether methamphetamine also produces this particular pattern of disruption in delayed matching-to-sample performance in rats. Methamphetamine primarily reduced accuracy on trials where the correct response differed from the one made on the previous trial. Thus methamphetamine, like MDMA and other stimulant-based drugs of abuse, increased proactive interference. This impairment was reduced by prior administration of the dopamine D1 antagonist SCH23390. These results further extend a general conclusion that a range of stimulant-based drugs may disrupt working memory function indirectly via a tendency to repeat previously made responses and that this disruption is related to D1 receptor activity. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Cognitive control of familiarity: directed forgetting reduces proactive interference in working memory.

    PubMed

    Festini, Sara B; Reuter-Lorenz, Patricia A

    2014-03-01

    Proactive interference (PI) occurs when previously learned information interferes with new learning. In a working memory task, PI induces longer response times and more errors to recent negative probes than to new probes, presumably because the recent probe's familiarity invites a "yes" response. Warnings, longer intertrial intervals, and the increased contextual salience of the probes can reduce but not eliminate PI, suggesting that cognitive control over PI is limited. Here we tested whether control exerted in the form of intentional forgetting performed during working memory can reduce the magnitude of PI. In two experiments, participants performed a working memory task with directed-forgetting instructions and the occasional presentation of recent probes. Surprise long-term memory testing indicated better memory for to-be-remembered than for to-be-forgotten items, documenting the classic directed-forgetting effect. Critically, in working memory, PI was virtually eliminated for recent probes from prior to-be-forgotten lists, as compared to recent probes from prior to-be-remembered lists. Thus cognitive control, when executed via directed forgetting, can reduce the adverse and otherwise persistent interference from familiarity, an effect that we attribute to attenuated memory representations of the to-be-forgotten items.

  20. The organizational implications of smokeless tobacco use in the lumber mill industry.

    PubMed

    Donaldson, S I; Dent, C W; Sussman, S; Stoddard, J L; Severson, H H

    1996-01-01

    Although much is known about the characteristics of employees who smoke cigarettes, very little is known about workers who use smokeless tobacco. The current study was designed to understand the characteristics of smokeless tobacco users in relation to their performance at work and compare them with smokers and former tobacco users. Data were collected via interviews and questionnaires from a random sample of employees working at Pacific Lumber Company (N = 146), the largest single-site lumber mill in California. A total of 63 smokeless tobacco users (21 of whom also smoked cigarettes), 43 cigarette smokers, and 40 employees who had successfully quit using tobacco (34 of whom previously used cigarettes only) provided information about their health behavior, quality of work life, and performance at work. Analyses revealed that smokeless tobacco users reported less healthful sleep patterns, drank alcohol more often, were intoxicated more often, reported less job satisfaction and organizational commitment, and reported that both chewers and smokers do not work as hard and take more breaks than do tobacco-free employees (quitters). Specific differences among chewers-only, smokers-only, smokers-and-chewers, and quitters are presented. Results suggest the organizational value of developing worksite cessation programs for smokeless tobacco users.

  1. A New Class of Macrocyclic Chiral Selectors for Stereochemical Analysis

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

    NONE

    1999-03-11

    This report summarizes the work accomplished in the authors laboratories over the previous three years. During the funding period they have had 23 monographs published or in press, 1 book chapter, 1 patent issued and have delivered 28 invited seminars or plenary lectures on DOE sponsored research. This report covers the work that has been published (or accepted). The most notable aspect of this work involves the successful development and understanding of a new class of fused macrocyclic compounds as pseudophases and selectors in high performance separations (including high performance liquid chromatography, HPLC; capillary electrophoresis, CE; and thin layer chromatography,more » TLC). They have considerably extended their chiral biomarker work from amber to crude oil and coal. In the process of doing this we've developed several novel separation approaches. They finished their work on the new GSC-PLOT column which is now being used by researchers world-wide for the analysis of gases, light hydrocarbons and halocarbons. Finally, we completed basic studies on immobilizing a cyclodextrin/oligosiloxane hybrid on the wall of fused silica, as well as a basic study on the separation behavior of buckminster fullerene and higher fullerenes.« less

  2. Perceived health and work-environment related problems and associated subjective production loss in an academic population.

    PubMed

    Lohela-Karlsson, Malin; Nybergh, Lotta; Jensen, Irene

    2018-02-14

    The aim was to investigate the prevalence of health problems and work environment problems and how these are associated with subjective production loss among women and men at an academic workplace. An additional aim was to investigate whether there were differences between women and men according to age group, years at current workplace, academic rank or managerial position. A questionnaire was sent in 2011 to all employees at a Swedish university (n = 5144). Only researchers and teachers were included in the study (n = 3207). Spearman correlations were performed to investigate differences in health and work environment problems. Employees who reported having experienced work environment or health problems in the previous seven days (n = 1475) were included in the analyses in order to investigate differences in subjective production loss. This was done using Student's t-test, One-way Anova and generalized linear models. The response rate was 63% (n = 2022). A total of 819 academic staff (40% of the population) reported experiencing either health problems, work environment problems or both during the previous seven days. The prevalence of health problems only or a combination of work environment and health problems was higher among women than men (p-value ˂0.05). This was especially the case for younger women, those in lower academic positions and those who had worked for fewer years at their current workplace. No difference was found for work environment problems. The majority of the employees who reported problems said that these problems affected their ability to perform at work (84-99%). The average production loss varied between 31 and 42% depending on the type of problem. Production loss due to health-related and work-environment related problems was highest among junior researchers and managers. No significant difference between men and women was found in the level of production loss. Subjective production loss in academia can be associated with health and work- environment problems. These losses appear similar for women and men even though younger female academics, women in lower academic ranks and those with fewer years of employment in their current workplace report a higher prevalence of health problems and combined work-environment and health problems than men.

  3. Does oxytocin lead to emotional interference during a working memory paradigm?

    PubMed

    Tollenaar, Marieke S; Ruissen, M; Elzinga, B M; de Bruijn, E R A

    2017-12-01

    Oxytocin administration may increase attention to emotional information. We hypothesized that this augmented emotional processing might in turn lead to interference on concurrent cognitive tasks. To test this hypothesis, we examined whether oxytocin administration would lead to heightened emotional interference during a working memory paradigm. Additionally, moderating effects of childhood maltreatment were explored. Seventy-eight healthy males received 24 IU of intranasal oxytocin or placebo in a randomized placebo-controlled double-blind between-subjects study. A working memory task was performed during which neutral, positive, and negative distractors were presented. The main outcome observed was that oxytocin did not enhance interference by emotional information during the working memory task. There was a non-significant trend for oxytocin to slow down performance irrespective of distractor valence, while accuracy was unaffected. Exploratory analyses showed that childhood maltreatment was related to lower overall accuracy, but in the placebo condition only. However, the maltreated group sample size was very small precluding any conclusions on its moderating effect. Despite oxytocin's previously proposed role in enhanced emotional processing, no proof was found that this would lead to reduced performance on a concurrent cognitive task. The routes by which oxytocin exerts its effects on cognitive and social-emotional processes remain to be fully elucidated.

  4. Implementation of a model based fault detection and diagnosis for actuation faults of the Space Shuttle main engine

    NASA Technical Reports Server (NTRS)

    Duyar, A.; Guo, T.-H.; Merrill, W.; Musgrave, J.

    1992-01-01

    In a previous study, Guo, Merrill and Duyar, 1990, reported a conceptual development of a fault detection and diagnosis system for actuation faults of the space shuttle main engine. This study, which is a continuation of the previous work, implements the developed fault detection and diagnosis scheme for the real time actuation fault diagnosis of the space shuttle main engine. The scheme will be used as an integral part of an intelligent control system demonstration experiment at NASA Lewis. The diagnosis system utilizes a model based method with real time identification and hypothesis testing for actuation, sensor, and performance degradation faults.

  5. Doing the hard work where it's easiest? Examining the relationships between urban greening programs and social and ecological characteristics

    Treesearch

    Dexter H. Locke; J. Morgan Grove

    2016-01-01

    In this paper we examine the performance of formal programs associated with tree plantings in Washington, D.C. and Baltimore, MD to understand the relationships between the implementation of urban greening programs and the social and ecological characteristics of a city. Previous research has examined variations in patterns of existing and possible tree canopy cover...

  6. Nonlinear Multidimensional Assignment Problems Efficient Conic Optimization Methods and Applications

    DTIC Science & Technology

    2015-06-24

    WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Arizona State University School of Mathematical & Statistical Sciences 901 S...SUPPLEMENTARY NOTES 14. ABSTRACT The major goals of this project were completed: the exact solution of previously unsolved challenging combinatorial optimization... combinatorial optimization problem, the Directional Sensor Problem, was solved in two ways. First, heuristically in an engineering fashion and second, exactly

  7. Electronics for a focal plane crystal spectrometer

    NASA Technical Reports Server (NTRS)

    Goeke, R. F.

    1978-01-01

    The HEAO-B program forced the usual constraints upon the spacecraft experiment electronics: high reliability, low power consumption, and tight packaging at reasonable cost. The programmable high voltage power supplies were unique in both application and simplicity of manufacture. The hybridized measurement chain is a modification of that used on the SAS-C program; the charge amplifier design in particular shows definite improvement in performance over previous work.

  8. Development and validation of a web-based questionnaire for surveying the health and working conditions of high-performance marine craft populations

    PubMed Central

    de Alwis, Manudul Pahansen; Lo Martire, Riccardo; Äng, Björn O; Garme, Karl

    2016-01-01

    Background High-performance marine craft crews are susceptible to various adverse health conditions caused by multiple interactive factors. However, there are limited epidemiological data available for assessment of working conditions at sea. Although questionnaire surveys are widely used for identifying exposures, outcomes and associated risks with high accuracy levels, until now, no validated epidemiological tool exists for surveying occupational health and performance in these populations. Aim To develop and validate a web-based questionnaire for epidemiological assessment of occupational and individual risk exposure pertinent to the musculoskeletal health conditions and performance in high-performance marine craft populations. Method A questionnaire for investigating the association between work-related exposure, performance and health was initially developed by a consensus panel under four subdomains, viz. demography, lifestyle, work exposure and health and systematically validated by expert raters for content relevance and simplicity in three consecutive stages, each iteratively followed by a consensus panel revision. The item content validity index (I-CVI) was determined as the proportion of experts giving a rating of 3 or 4. The scale content validity index (S-CVI/Ave) was computed by averaging the I-CVIs for the assessment of the questionnaire as a tool. Finally, the questionnaire was pilot tested. Results The S-CVI/Ave increased from 0.89 to 0.96 for relevance and from 0.76 to 0.94 for simplicity, resulting in 36 items in the final questionnaire. The pilot test confirmed the feasibility of the questionnaire. Conclusions The present study shows that the web-based questionnaire fulfils previously published validity acceptance criteria and is therefore considered valid and feasible for the empirical surveying of epidemiological aspects among high-performance marine craft crews and similar populations. PMID:27324717

  9. The authentic worker's well-being and performance: the relationship between authenticity at work, well-being, and work outcomes.

    PubMed

    van den Bosch, Ralph; Taris, Toon W

    2014-01-01

    Previous research on authenticity has mainly focused on trait conceptualizations of authenticity (e.g., Wood et al., 2008), whereas in specific environments (e.g., at work) state conceptualizations of authenticity (cf. Van den Bosch & Taris, 2013) are at least as relevant. For example, working conditions are subject to change, and this could well have consequences for employees' perceived level of authenticity at work. The current study employs a work-specific, state-like conceptualization of authenticity to investigate the relations between authenticity at work, well-being, and work outcomes. A series of ten separate hierarchical regression analyses using data from 685 participants indicated that after controlling for selected work characteristics and demographic variables, authenticity at work accounted for on average 11% of the variance of various wellbeing and work outcomes. Of the three subscales of authenticity at work (i.e., authentic living, self-alienation, and accepting influence), self-alienation was the strongest predictor of outcomes, followed by authentic living and accepting external influence, respectively. These findings are discussed in the light of their practical and theoretical implications.

  10. A multidisciplinary approach of workload assessment in real-job situations: investigation in the field of aerospace activities.

    PubMed

    Mélan, Claudine; Cascino, Nadine

    2014-01-01

    The present contribution presents two field studies combining tools and methods from cognitive psychology and from occupational psychology in order to perform a thorough investigation of workload in employees. Cognitive load theory proposes to distinguish different load categories of working memory, in a context of instruction. Intrinsic load is inherent to the task, extraneous load refers to components of a learning environment that may be modified to reduce total load, and germane load enables schemas construction and thus efficient learning. We showed previously that this theoretical framework may be successfully extended to working memory tasks in non-instructional designs. Other theoretical models, issued from the field of occupational psychology, account for an individual's perception of work demands or requirements in the context of different psychosocial features of the (work) environment. Combining these approaches is difficult as workload assessment by job-perception questionnaires explore an individual's overall job-perception over a large time-period, whereas cognitive load investigations in working memory tasks are typically performed within short time-periods. We proposed an original methodology enabling investigation of workload and load factors in a comparable time-frame. We report two field studies investigating workload on different shift-phases and between work-shifts, with two custom-made tools. The first one enabled workload assessment by manipulating intrinsic load (task difficulty) and extraneous load (time pressure) in a working-memory task. The second tool was a questionnaire based on the theoretical concepts of work-demands, control, and psychosocial support. Two additional dimensions suspected to contribute to job-perception, i.e., work-family conflicts and availability of human and technical resources were also explored. Results of workload assessments were discussed in light of operators' alertness and job-performance.

  11. Inhibition in movement plan competition: reach trajectories curve away from remembered and task-irrelevant present but not from task-irrelevant past visual stimuli.

    PubMed

    Moehler, Tobias; Fiehler, Katja

    2017-11-01

    The current study investigated the role of automatic encoding and maintenance of remembered, past, and present visual distractors for reach movement planning. The previous research on eye movements showed that saccades curve away from locations actively kept in working memory and also from task-irrelevant perceptually present visual distractors, but not from task-irrelevant past distractors. Curvature away has been associated with an inhibitory mechanism resolving the competition between multiple active movement plans. Here, we examined whether reach movements underlie a similar inhibitory mechanism and thus show systematic modulation of reach trajectories when the location of a previously presented distractor has to be (a) maintained in working memory or (b) ignored, or (c) when the distractor is perceptually present. Participants performed vertical reach movements on a computer monitor from a home to a target location. Distractors appeared laterally and near or far from the target (equidistant from central fixation). We found that reaches curved away from the distractors located close to the target when the distractor location had to be memorized and when it was perceptually present, but not when the past distractor had to be ignored. Our findings suggest that automatically encoding present distractors and actively maintaining the location of past distractors in working memory evoke a similar response competition resolved by inhibition, as has been previously shown for saccadic eye movements.

  12. Effect of subthalamic nucleus deep brain stimulation on dual-task cognitive and motor performance in isolated dystonia.

    PubMed

    Mills, Kelly A; Markun, Leslie C; San Luciano, Marta; Rizk, Rami; Allen, I Elaine; Racine, Caroline A; Starr, Philip A; Alberts, Jay L; Ostrem, Jill L

    2015-04-01

    Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor complications of Parkinson's disease (PD) but may worsen specific cognitive functions. The effect of STN DBS on cognitive function in dystonia patients is less clear. Previous reports indicate that bilateral STN stimulation in patients with PD amplifies the decrement in cognitive-motor dual-task performance seen when moving from a single-task to dual-task paradigm. We aimed to determine if the effect of bilateral STN DBS on dual-task performance in isolated patients with dystonia, who have less cognitive impairment and no dementia, is similar to that seen in PD. Eight isolated predominantly cervical patients with dystonia treated with bilateral STN DBS, with average dystonia duration of 10.5 years and Montreal Cognitive Assessment score of 26.5, completed working memory (n-back) and motor (forced-maintenance) tests under single-task and dual-task conditions while on and off DBS. A multivariate, repeated-measures analysis of variance showed no effect of stimulation status (On vs Off) on working memory (F=0.75, p=0.39) or motor function (F=0.22, p=0.69) when performed under single-task conditions, though as working memory task difficulty increased, stimulation disrupted the accuracy of force-tracking. There was a very small worsening in working memory performance (F=9.14, p=0.019) when moving from single-task to dual-tasks when using the 'dual-task loss' analysis. This study suggests the effect of STN DBS on working memory and attention may be much less consequential in patients with dystonia than has been reported in PD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. Effect of subthalamic nucleus deep brain stimulation on dual-task cognitive and motor performance in isolated dystonia

    PubMed Central

    Mills, Kelly A; Markun, Leslie C; Luciano, Marta San; Rizk, Rami; Allen, I Elaine; Racine, Caroline A; Starr, Philip A; Alberts, Jay L; Ostrem, Jill L

    2015-01-01

    Objective Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor complications of Parkinson's disease (PD) but may worsen specific cognitive functions. The effect of STN DBS on cognitive function in dystonia patients is less clear. Previous reports indicate that bilateral STN stimulation in patients with PD amplifies the decrement in cognitive-motor dual-task performance seen when moving from a single-task to dual-task paradigm. We aimed to determine if the effect of bilateral STN DBS on dual-task performance in isolated patients with dystonia, who have less cognitive impairment and no dementia, is similar to that seen in PD. Methods Eight isolated predominantly cervical patients with dystonia treated with bilateral STN DBS, with average dystonia duration of 10.5 years and Montreal Cognitive Assessment score of 26.5, completed working memory (n-back) and motor (forced-maintenance) tests under single-task and dual-task conditions while on and off DBS. Results A multivariate, repeated-measures analysis of variance showed no effect of stimulation status (On vs Off) on working memory (F=0.75, p=0.39) or motor function (F=0.22, p=0.69) when performed under single-task conditions, though as working memory task difficulty increased, stimulation disrupted the accuracy of force-tracking. There was a very small worsening in working memory performance (F=9.14, p=0.019) when moving from single-task to dual-tasks when using the ‘dual-task loss’ analysis. Conclusions This study suggests the effect of STN DBS on working memory and attention may be much less consequential in patients with dystonia than has been reported in PD. PMID:25012202

  14. Cooperative Learning and Interpersonal Synchrony.

    PubMed

    Vink, Roy; Wijnants, Maarten L; Cillessen, Antonius H N; Bosman, Anna M T

    2017-04-01

    Cooperative learning has been shown to result in better task performance, compared to individual and competitive learning, and can lead to positive social effects. However, potential working mechanisms at a micro level remain unexplored. One potential working mechanism might be the level of interpersonal synchrony between cooperating individuals. It has been shown that increased levels of interpersonal synchrony are related to better cognitive performance (e.g., increased memory). Social factors also appear to be affected by the level of interpersonal synchrony, with more interpersonal synchrony leading to increased likeability. In the present study, interpersonal synchrony of postural sway and its relation to task performance and social factors (i.e., popularity, social acceptance, and likeability) was examined. To test this, 183 dyads performed a tangram task while each child stood on a Nintendo Wii Balance Board that recorded their postural sway. The results showed that lower levels of interpersonal synchrony were related to better task performance and those dyads who were on average more popular synchronized more. These results contradict previous findings. It is suggested that for task performance, a more loosely coupled system is better than a synchronized system. In terms of social competence, dyad popularity was associated with more interpersonal synchrony.

  15. Liver Full Reference Set Application: David Lubman - Univ of Michigan (2011) — EDRN Public Portal

    Cancer.gov

    In this work we will perform the next step in the biomarker development and validation. This step will be the Phase 2 validation of glycoproteins that have passed Phase 1 blinded validation using ELISA kits based on target glycoproteins selected based on our previous work. This will be done in a large Phase 2 sample set obtained in a multicenter study funded by the EDRN. The assays will be performed in our research lab located in the Center for Cancer Proteomics in the University of Michigan Medical Center. This study will include patients in whom serum was stored for future validation and includes samples from early HCC (n = 158), advanced cases (n=214) and cirrhotic controls (n = 417). These samples will be supplied by the EDRN (per Dr. Jo Ann Rinaudo) and will be analyzed in a blinded fashion by Dr. Feng from the Fred Hutchinson Cancer Center. This phase 2 study was designed to have above 90% power at one-sided 5% type-I error for comparing the joint sensitivity and specificity for differentiating early stage HCC from cirrhotic patients between AFP and a new marker. Sample sizes of 200 for early stage HCC and 400 for cirrhotics were required to achieve the stated power (14). We will select our candidates for this larger phase validation set based on the results of previous work. These will include HGF and CD14 and the results of these assays will be used to evaluate the performance of each of these markers and combinations of HGF and CD14 and AFP and HGF. It is expected that each assay will be repeated three times for each marker and will also be performed for AFP as the standard for comparison. 250 uL of each sample is requested for analysis.

  16. Enhanced automated platform for 2D characterization of RFID communications

    NASA Astrophysics Data System (ADS)

    Vuza, Dan Tudor; Vlǎdescu, Marian

    2016-12-01

    The characterization of the quality of communication between an RFID reader and a transponder at all expected positions of the latter on the reader antenna is of primal importance for the evaluation of performance of an RFID system. Continuing the line of instruments developed for this purpose by the authors, the present work proposes an enhanced version of a previously introduced automated platform for 2D evaluation. By featuring higher performance in terms of mechanical speed, the new version allows to obtain 2D maps of communication with a higher resolution that would have been prohibitive in terms of test duration with the previous version. The list of measurement procedures that can be executed with the platform is now enlarged with additional ones, such as the determination of the variation of the magnetic coupling between transponder and antenna across the antenna surface and the utilization of transponder simulators for evaluation of the quality of communication.

  17. Stepwise and stagewise approaches for spatial cluster detection

    PubMed Central

    Xu, Jiale

    2016-01-01

    Spatial cluster detection is an important tool in many areas such as sociology, botany and public health. Previous work has mostly taken either hypothesis testing framework or Bayesian framework. In this paper, we propose a few approaches under a frequentist variable selection framework for spatial cluster detection. The forward stepwise methods search for multiple clusters by iteratively adding currently most likely cluster while adjusting for the effects of previously identified clusters. The stagewise methods also consist of a series of steps, but with tiny step size in each iteration. We study the features and performances of our proposed methods using simulations on idealized grids or real geographic area. From the simulations, we compare the performance of the proposed methods in terms of estimation accuracy and power of detections. These methods are applied to the the well-known New York leukemia data as well as Indiana poverty data. PMID:27246273

  18. Stepwise and stagewise approaches for spatial cluster detection.

    PubMed

    Xu, Jiale; Gangnon, Ronald E

    2016-05-01

    Spatial cluster detection is an important tool in many areas such as sociology, botany and public health. Previous work has mostly taken either a hypothesis testing framework or a Bayesian framework. In this paper, we propose a few approaches under a frequentist variable selection framework for spatial cluster detection. The forward stepwise methods search for multiple clusters by iteratively adding currently most likely cluster while adjusting for the effects of previously identified clusters. The stagewise methods also consist of a series of steps, but with a tiny step size in each iteration. We study the features and performances of our proposed methods using simulations on idealized grids or real geographic areas. From the simulations, we compare the performance of the proposed methods in terms of estimation accuracy and power. These methods are applied to the the well-known New York leukemia data as well as Indiana poverty data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. ELHnet: a convolutional neural network for classifying cochlear endolymphatic hydrops imaged with optical coherence tomography.

    PubMed

    Liu, George S; Zhu, Michael H; Kim, Jinkyung; Raphael, Patrick; Applegate, Brian E; Oghalai, John S

    2017-10-01

    Detection of endolymphatic hydrops is important for diagnosing Meniere's disease, and can be performed non-invasively using optical coherence tomography (OCT) in animal models as well as potentially in the clinic. Here, we developed ELHnet, a convolutional neural network to classify endolymphatic hydrops in a mouse model using learned features from OCT images of mice cochleae. We trained ELHnet on 2159 training and validation images from 17 mice, using only the image pixels and observer-determined labels of endolymphatic hydrops as the inputs. We tested ELHnet on 37 images from 37 mice that were previously not used, and found that the neural network correctly classified 34 of the 37 mice. This demonstrates an improvement in performance from previous work on computer-aided classification of endolymphatic hydrops. To the best of our knowledge, this is the first deep CNN designed for endolymphatic hydrops classification.

  20. ELHnet: a convolutional neural network for classifying cochlear endolymphatic hydrops imaged with optical coherence tomography

    PubMed Central

    Liu, George S.; Zhu, Michael H.; Kim, Jinkyung; Raphael, Patrick; Applegate, Brian E.; Oghalai, John S.

    2017-01-01

    Detection of endolymphatic hydrops is important for diagnosing Meniere’s disease, and can be performed non-invasively using optical coherence tomography (OCT) in animal models as well as potentially in the clinic. Here, we developed ELHnet, a convolutional neural network to classify endolymphatic hydrops in a mouse model using learned features from OCT images of mice cochleae. We trained ELHnet on 2159 training and validation images from 17 mice, using only the image pixels and observer-determined labels of endolymphatic hydrops as the inputs. We tested ELHnet on 37 images from 37 mice that were previously not used, and found that the neural network correctly classified 34 of the 37 mice. This demonstrates an improvement in performance from previous work on computer-aided classification of endolymphatic hydrops. To the best of our knowledge, this is the first deep CNN designed for endolymphatic hydrops classification. PMID:29082086

  1. Efficient globally optimal segmentation of cells in fluorescence microscopy images using level sets and convex energy functionals.

    PubMed

    Bergeest, Jan-Philip; Rohr, Karl

    2012-10-01

    In high-throughput applications, accurate and efficient segmentation of cells in fluorescence microscopy images is of central importance for the quantification of protein expression and the understanding of cell function. We propose an approach for segmenting cell nuclei which is based on active contours using level sets and convex energy functionals. Compared to previous work, our approach determines the global solution. Thus, the approach does not suffer from local minima and the segmentation result does not depend on the initialization. We consider three different well-known energy functionals for active contour-based segmentation and introduce convex formulations of these functionals. We also suggest a numeric approach for efficiently computing the solution. The performance of our approach has been evaluated using fluorescence microscopy images from different experiments comprising different cell types. We have also performed a quantitative comparison with previous segmentation approaches. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Magical ideation and right-sided hemispatial inattention on a spatial working memory task: influences of sex and handedness.

    PubMed

    Nalçaci, E; Kalaycioglu, C; Ciçek, M; Budanur, O E

    2000-12-01

    A correlation between magical ideation scores and the size of relative right-sided hemispatial inattention was previously reported for healthy right-handed men performing a tactile line-bisection task. To re-investigate this relation, a computerized version of Corsi's Block-Tapping Test was used to test working memory. In this version, different numbers of cubes are similtaneously displayed on a screen, and after the cubes disappear the subject is asked to designate the cubes' locations on a grid as quickly as possible. 98 healtly medical students were divided into four groups on the basis of their handedness and sex in the following way: right-handed men, right-handed women, nonright-handed men, and nonright-handed women. Each subject performed the test once with the right hand and once with the left hand. Accuracy and Neglect scores were computed for the two hemispaces separately. Also, all subjects filled in the Magical Ideation Scale which asks for hallucination-like experiences and delusion-like beliefs. In all groups a significant right-sided inattention was found when subjects performed with the right hand. Magical Ideation scores were significantly correlated with Neglect in the right hemispace for the right-handed women when the right hand was used. For the nonright-handed men, when the right hand was used, a significant negative correlation between Magical Ideation scores and Neglect scores in the left hemispace was found. Our findings support the previous study in some aspects and suggest that the correlation between hemispatial inattention and proneness to schizotypy in normal subjects is restricted to right-hand performance.

  3. Individual differences in media multitasking and performance on the n-back.

    PubMed

    Ralph, Brandon C W; Smilek, Daniel

    2017-02-01

    A number of studies have recently examined the link between individual differences in media multitasking (using the MMI) and performance on working memory paradigms. However, these studies have yielded mixed results. Here we examine the relation between media multitasking and one particular working memory paradigm-the n-back (2- and 3-back)-improving upon previous research by (a) treating media multitasking as a continuous variable and adopting a correlational approach as well as (b) using a large sample of participants. First, we found that higher scores on the MMI were associated with a greater proportion of omitted trials on both the 2-back and 3-back, indicating that heavier media multitaskers were more disengaged during the n-back. In line with such a claim, heavier media multitaskers were also more likely to confess to responding randomly during various portions of the experiment, and to report media multitasking during the experiment itself. Importantly, when controlling for the relation between MMI scores and omissions, higher scores on the MMI were associated with an increase in false alarms, but not with a change in hits. These findings refine the extant literature on media multitasking and working memory performance (specifically, performance on the n-back), and suggest that media multitasking may be related to the propensity to disengage from ongoing tasks.

  4. Graphic support resources for workers with intellectual disability engaged in office tasks: a comparison with verbal instructions from a work mate.

    PubMed

    Becerra, María-Teresa; Montanero, Manuel; Lucero, Manuel

    2018-02-01

    Research into workplace adjustments for people with disabilities is a fundamental challenge of supported employment. The aim of the present work is to investigate the effect of several graphic resources as natural support for workers with intellectual disability. Two case studies were conducted to assess the performance of five workers engaged in office tasks, with three different support conditions. Results reveal a 20% increase in quality of performance of the tasks undertaken with graphic support as compared to support in which the participants received verbal instructions (VIs) from a work mate; and between 25 and 30% as compared to a control condition which included no help of any kind. These findings are consistent with previous studies which support the possibility of generating, at low cost, iconic materials (with maps or simple graphics), which progressively facilitate workers' autonomy, without dependence or help from the job trainer. We observed that the worst performance is in the support condition with VIs, this shows the limitations of this type of natural support, which is provided on demand by work mates without specialist knowledge of work support. Implications for Rehabilitation We studied the use of various types of natural support for people with intellectual disability in their workplace. The findings suggest that, with some brief training, the simple use in the workplace of graphic help on a card can increase between 20 and 30% the quality of performance of certain work tasks carried out by workers with intellectual disability. This advantage contrasts with the high cost or lower "manageability" of other material resources of natural support based on the use of technology.

  5. Effects of Age and Working Memory Capacity on Speech Recognition Performance in Noise Among Listeners With Normal Hearing.

    PubMed

    Gordon-Salant, Sandra; Cole, Stacey Samuels

    2016-01-01

    This study aimed to determine if younger and older listeners with normal hearing who differ on working memory span perform differently on speech recognition tests in noise. Older adults typically exhibit poorer speech recognition scores in noise than younger adults, which is attributed primarily to poorer hearing sensitivity and more limited working memory capacity in older than younger adults. Previous studies typically tested older listeners with poorer hearing sensitivity and shorter working memory spans than younger listeners, making it difficult to discern the importance of working memory capacity on speech recognition. This investigation controlled for hearing sensitivity and compared speech recognition performance in noise by younger and older listeners who were subdivided into high and low working memory groups. Performance patterns were compared for different speech materials to assess whether or not the effect of working memory capacity varies with the demands of the specific speech test. The authors hypothesized that (1) normal-hearing listeners with low working memory span would exhibit poorer speech recognition performance in noise than those with high working memory span; (2) older listeners with normal hearing would show poorer speech recognition scores than younger listeners with normal hearing, when the two age groups were matched for working memory span; and (3) an interaction between age and working memory would be observed for speech materials that provide contextual cues. Twenty-eight older (61 to 75 years) and 25 younger (18 to 25 years) normal-hearing listeners were assigned to groups based on age and working memory status. Northwestern University Auditory Test No. 6 words and Institute of Electrical and Electronics Engineers sentences were presented in noise using an adaptive procedure to measure the signal-to-noise ratio corresponding to 50% correct performance. Cognitive ability was evaluated with two tests of working memory (Listening Span Test and Reading Span Test) and two tests of processing speed (Paced Auditory Serial Addition Test and The Letter Digit Substitution Test). Significant effects of age and working memory capacity were observed on the speech recognition measures in noise, but these effects were mediated somewhat by the speech signal. Specifically, main effects of age and working memory were revealed for both words and sentences, but the interaction between the two was significant for sentences only. For these materials, effects of age were observed for listeners in the low working memory groups only. Although all cognitive measures were significantly correlated with speech recognition in noise, working memory span was the most important variable accounting for speech recognition performance. The results indicate that older adults with high working memory capacity are able to capitalize on contextual cues and perform as well as young listeners with high working memory capacity for sentence recognition. The data also suggest that listeners with normal hearing and low working memory capacity are less able to adapt to distortion of speech signals caused by background noise, which requires the allocation of more processing resources to earlier processing stages. These results indicate that both younger and older adults with low working memory capacity and normal hearing are at a disadvantage for recognizing speech in noise.

  6. Self-Reported Work Ability Predicts Rehabilitation Measures, Disability Pensions, Other Welfare Benefits, and Work Participation: Longitudinal Findings from a Sample of German Employees.

    PubMed

    Bethge, Matthias; Spanier, Katja; Peters, Elke; Michel, Elliot; Radoschewski, Michael

    2017-09-27

    Purpose The study examined the performance of the Work Ability Index in predicting rehabilitation measures and disability pensions, sickness absence and unemployment benefits, and work participation among a sample of workers previously receiving sickness absence benefits. Methods Workers aged 40 to 54 years who received sickness absence benefits in 2012 completed the Work Ability Index in 2013. Outcomes were extracted from administrative data records. Results Data for 2149 participants were included (mean age: 47.8 years; 54.4% women). Mean follow-up was 19 months. Work Ability Index scores were poor (7-27 points) in 21% of the participants, and moderate (28-36 points) in 38.4%. In all, 224 rehabilitation measures and 35 disability pensions were approved. Fully adjusted analyses showed increased risk of rehabilitation measures in workers with poor (HR 4.55; 95% CI 3.14-6.60) and moderate scores (HR 2.08; 95% CI 1.43-3.01) compared to workers with good or excellent scores (37-49 points). The risk of a disability pension increased significantly for workers with poor scores (HR 7.78; 95% CI 2.59-23.35). In addition, poor scores were prospectively associated with a longer duration of sickness absence and employment benefits, and fewer employment days and less income from regular employment. Conclusions The Work Ability Index is a potential tool for following up workers who already have an increased risk of permanent work disability due to previous long-term sickness absence.

  7. Use of an eight-arm radial water maze to assess working and reference memory following neonatal brain injury.

    PubMed

    Penley, Stephanie C; Gaudet, Cynthia M; Threlkeld, Steven W

    2013-12-04

    Working and reference memory are commonly assessed using the land based radial arm maze. However, this paradigm requires pretraining, food deprivation, and may introduce scent cue confounds. The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs. Specifically, subjects are required to avoid the arms previously used for escape during each testing day (working memory) as well as avoid the fixed arms, which never contain escape platforms (reference memory). Re-entries into arms that have already been used for escape during a testing session (and thus the escape platform has been removed) and re-entries into reference memory arms are indicative of working memory deficits. Alternatively, first entries into reference memory arms are indicative of reference memory deficits. We used this maze to compare performance of rats with neonatal brain injury and sham controls following induction of hypoxia-ischemia and show significant deficits in both working and reference memory after eleven days of testing. This protocol could be easily modified to examine many other models of learning impairment.

  8. Indexing Volumetric Shapes with Matching and Packing

    PubMed Central

    Koes, David Ryan; Camacho, Carlos J.

    2014-01-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X. PMID:26085707

  9. Heart rate variability and cortisol responses during attentional and working memory tasks in naval cadets.

    PubMed

    Johnsen, Bjørn Helge; Hansen, Anita L; Murison, Robert; Eid, Jarle; Thayer, Julian F

    2012-01-01

    The aim of the paper was to study the relationship between heart rate variability (HRV) and cortisol release during cognitive challenging tasks. Forty-nine male naval cadets from the Royal Norwegian Naval Academy were administered computerised versions of attentional and working memory tests. The results from this study support the hypothesis of a negative correlation between HRV and cortisol secretion during cognitive tasks. Confirmation of the hypothesis with the low HRV group scoring higher on cortisol only during performance of cognitive tasks and recovery was also found. Furthermore, a replication of the previous findings of a negative association between cortisol levels and performance were supported when using uncorrected comparisons. None of the correlations survived Bonferonin corrections. The findings are discussed in relation to factors increasing HRV, thus improving tolerance to cognitive stress in onboard environments.

  10. Contextual analysis of fluid intelligence.

    PubMed

    Salthouse, Timothy A; Pink, Jeffrey E; Tucker-Drob, Elliot M

    2008-01-01

    The nature of fluid intelligence was investigated by identifying variables that were, and were not, significantly related to this construct. Relevant information was obtained from three sources: re-analyses of data from previous studies, a study in which 791 adults performed storage-plus-processing working memory tasks, and a study in which 236 adults performed a variety of working memory, updating, and cognitive control tasks. The results suggest that fluid intelligence represents a broad individual difference dimension contributing to diverse types of controlled or effortful processing. The analyses also revealed that very few of the age-related effects on the target variables were statistically independent of effects on established cognitive abilities, which suggests most of the age-related influences on a wide variety of cognitive control variables overlap with age-related influences on cognitive abilities such as fluid intelligence, episodic memory, and perceptual speed.

  11. Improving Lunar Exploration with Robotic Follow-up

    NASA Technical Reports Server (NTRS)

    Fong, T.; Bualat, M.; Deans, M.; Heggy E.; Helper, M.; Hodges, K.; Lee, P.

    2011-01-01

    We are investigating how augmenting human field work with subsequent robot activity can improve lunar exploration. Robotic "follow-up" might involve: completing geology observations; making tedious or long-duration measurements of a target site or feature; curating samples in-situ; and performing unskilled, labor-intensive work. To study this technique, we have begun conducting a series of lunar analog field tests at Haughton Crater (Canada). Motivation: In most field geology studies on Earth, explorers often find themselves left with a set of observations they would have liked to make, or samples they would have liked to take, if only they had been able to stay longer in the field. For planetary field geology, we can imagine mobile robots - perhaps teleoperated vehicles previously used for manned exploration or dedicated planetary rovers - being deployed to perform such follow-up activities [1].

  12. Factor structure of a standards-based inventory of competencies in social work with groups.

    PubMed

    Macgowan, Mark J; Dillon, Frank R; Spadola, Christine E

    2018-01-01

    This study extends previous findings on a measure of competencies based on Standards for Social Work Practice with Groups. The Inventory of Competencies in Social Work with Groups (ICSWG) measures confidence in performing the Standards. This study examines the latent structure of the Inventory, while illuminating the underlying structure of the Standards. A multinational sample of 586 persons completed the ICSWG. Exploratory factor analysis (EFA), reliability estimates, standard error of measurement estimates, and a range of validity tests were conducted. The EFA yielded a six-factor solution consisting of core values, mutuality/connectivity, collaboration, and three phases of group development (planning, beginnings/middles, endings). The alphas were .98 for the scale and ranged from .85 to .95 for the subscales. Correlations between the subscales and validators supported evidence of construct validity. The findings suggest key group work domains that should be taught and practiced in social work with groups.

  13. Choosing the appropriate forecasting model for predictive parameter control.

    PubMed

    Aleti, Aldeida; Moser, Irene; Meedeniya, Indika; Grunske, Lars

    2014-01-01

    All commonly used stochastic optimisation algorithms have to be parameterised to perform effectively. Adaptive parameter control (APC) is an effective method used for this purpose. APC repeatedly adjusts parameter values during the optimisation process for optimal algorithm performance. The assignment of parameter values for a given iteration is based on previously measured performance. In recent research, time series prediction has been proposed as a method of projecting the probabilities to use for parameter value selection. In this work, we examine the suitability of a variety of prediction methods for the projection of future parameter performance based on previous data. All considered prediction methods have assumptions the time series data has to conform to for the prediction method to provide accurate projections. Looking specifically at parameters of evolutionary algorithms (EAs), we find that all standard EA parameters with the exception of population size conform largely to the assumptions made by the considered prediction methods. Evaluating the performance of these prediction methods, we find that linear regression provides the best results by a very small and statistically insignificant margin. Regardless of the prediction method, predictive parameter control outperforms state of the art parameter control methods when the performance data adheres to the assumptions made by the prediction method. When a parameter's performance data does not adhere to the assumptions made by the forecasting method, the use of prediction does not have a notable adverse impact on the algorithm's performance.

  14. [Factors associated with work-related accidents in the informal commercial sector].

    PubMed

    Rios, Marcela Andrade; Nery, Adriana Alves; Rios, Polianna Alves Andrade; Casotti, Cezar Augusto; Cardoso, Jefferson Paixão

    2015-06-01

    This study aimed to estimate the incidence of non-fatal work-related accidents in the informal commercial sector and analyze associated socio-demographic, occupational, workplace, and health factors, in a cross-sectional survey of 434 workers in the business district of Jequié, Bahia State, Brazil, in 2013. Logistic regression was used to assess factors associated with accidents. Incidence of accidents in the previous 12 months was estimated at 32.3%, and multivariate analysis showed higher odds of accidents in male sex workers (OR = 1.61), young individuals (OR = 4.62), meat or poultry workers (OR = 9.55), and workers performing heavy physical work (OR = 1.71). The results show the need for public policies to prevent accidents in the informal commercial sector.

  15. Associations among false belief understanding, counterfactual reasoning, and executive function.

    PubMed

    Guajardo, Nicole R; Parker, Jessica; Turley-Ames, Kandi

    2009-09-01

    The primary purposes of the present study were to clarify previous work on the association between counterfactual thinking and false belief performance to determine (1) whether these two variables are related and (2) if so, whether executive function skills mediate the relationship. A total of 92 3-, 4-, and 5-year-olds completed false belief, counterfactual, working memory, representational flexibility, and language measures. Counterfactual reasoning accounted for limited unique variance in false belief. Both working memory and representational flexibility partially mediated the relationship between counterfactual and false belief. Children, like adults, also generated various types of counterfactual statements to differing degrees. Results demonstrated the importance of language and executive function for both counterfactual and false belief. Implications are discussed.

  16. Working memory capacity predicts listwise directed forgetting in adults and children.

    PubMed

    Aslan, Alp; Zellner, Martina; Bäuml, Karl-Heinz T

    2010-05-01

    In listwise directed forgetting, participants are cued to forget previously studied material and to learn new material instead. Such cueing typically leads to forgetting of the first set of material and to memory enhancement of the second. The present study examined the role of working memory capacity in adults' and children's listwise directed forgetting. Working memory capacity was assessed with complex span tasks. In Experiment 1 working memory capacity predicted young adults' directed-forgetting performance, demonstrating a positive relationship between working memory capacity and each of the two directed-forgetting effects. In Experiment 2 we replicated the finding with a sample of first and a sample of fourth-grade children, and additionally showed that working memory capacity can account for age-related increases in directed-forgetting efficiency between the two age groups. Following the view that directed forgetting is mediated by inhibition of the first encoded list, the results support the proposal of a close link between working memory capacity and inhibitory function.

  17. Self-reports of executive dysfunction in current ecstasy/polydrug Users.

    PubMed

    Hadjiefthyvoulou, Florentia; Fisk, John E; Montgomery, Catharine; Bridges, Nikola

    2012-09-01

    Ecstasy/polydrug users have exhibited deficits in executive functioning in laboratory tests. We sought to extend these findings by investigating the extent to which ecstasy/polydrug users manifest executive deficits in everyday life. Forty-two current ecstasy/polydrug users, 18 previous (abstinent for at least 6 months) ecstasy/polydrug users, and 50 non-users of ecstasy (including both non-users of any illicit drug and some cannabis-only users) completed the self-report Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) measure. Current ecstasy/polydrug users performed significantly worse than previous users and non-users on subscales measuring inhibition, self-monitoring, initiating action, working memory, planning, monitoring ongoing task performance, and organizational ability. Previous ecstasy/polydrug users did not differ significantly from non-users. In regression analyses, although the current frequency of ecstasy use accounted for statistically significant unique variance on 3 of the 9 BRIEF-A subscales, daily cigarette consumption was the main predictor in 6 of the subscales. Current ecstasy/polydrug users report more executive dysfunction than do previous users and non-users. This finding appears to relate to some aspect of ongoing ecstasy use and seems largely unrelated to the use of other illicit drugs. An unexpected finding was the association of current nicotine consumption with executive dysfunction.

  18. Sources of Cognitive Inflexibility in Set-Shifting Tasks: Insights Into Developmental Theories From Adult Data

    PubMed Central

    Dick, Anthony Steven

    2012-01-01

    Two experiments examined processes underlying cognitive inflexibility in set-shifting tasks typically used to assess the development of executive function in children. Adult participants performed a Flexible Item Selection Task (FIST) that requires shifting from categorizing by one dimension (e.g., color) to categorizing by a second orthogonal dimension (e.g., shape). The experiments showed performance of the FIST involves suppression of the representation of the ignored dimension; response times for selecting a target object in an immediately-following oddity task were slower when the oddity target was the previously-ignored stimulus of the FIST. However, proactive interference from the previously relevant stimulus dimension also impaired responding. The results are discussed with respect to two prominent theories of the source of difficulty for children and adults on dimensional shifting tasks: attentional inertia and negative priming. In contrast to prior work emphasizing one over the other process, the findings indicate that difficulty in the FIST, and by extension other set-shifting tasks, can be attributed to both the need to shift away from the previously attended representation (attentional inertia), and the need to shift to the previously ignored representation (negative priming). Results are discussed in relation to theoretical explanations for cognitive inflexibility in adults and children. PMID:23539267

  19. Sources of Cognitive Inflexibility in Set-Shifting Tasks: Insights Into Developmental Theories From Adult Data.

    PubMed

    Dick, Anthony Steven

    2012-01-01

    Two experiments examined processes underlying cognitive inflexibility in set-shifting tasks typically used to assess the development of executive function in children. Adult participants performed a Flexible Item Selection Task (FIST) that requires shifting from categorizing by one dimension (e.g., color) to categorizing by a second orthogonal dimension (e.g., shape). The experiments showed performance of the FIST involves suppression of the representation of the ignored dimension; response times for selecting a target object in an immediately-following oddity task were slower when the oddity target was the previously-ignored stimulus of the FIST. However, proactive interference from the previously relevant stimulus dimension also impaired responding. The results are discussed with respect to two prominent theories of the source of difficulty for children and adults on dimensional shifting tasks: attentional inertia and negative priming . In contrast to prior work emphasizing one over the other process, the findings indicate that difficulty in the FIST, and by extension other set-shifting tasks, can be attributed to both the need to shift away from the previously attended representation ( attentional inertia ), and the need to shift to the previously ignored representation ( negative priming ). Results are discussed in relation to theoretical explanations for cognitive inflexibility in adults and children.

  20. IBD-related work disability in the community: Prevalence, severity and predictive factors. A cross-sectional study

    PubMed Central

    Ramos, Alexis; Sicilia, Beatriz; Vergara, Mercedes; Figuerola, Ariadna; Motos, Jaume; Sastre, Adoración; Villoria, Albert; Gomollón, Fernando

    2015-01-01

    Background and aims Data on the prevalence of work disability in patients with inflammatory bowel disease (IBD) are heterogeneous. As most studies have been performed in selected, often severe, IBD patients, the true prevalence of disability in the community remains controversial. The aim of this cross-sectional study was to evaluate the prevalence and severity of disability and its predictive factors in a community-based IBD population. Patients and methods Patients recorded in the community-based IBD register at the Hospital Universitario de Burgos were contacted. After informed consent they completed a set of questionnaires including demographic, clinical, disability and quality of life data. The statistical study was performed using SPSS 21. Results A total of 293 patients were included – 151 Crohn's disease (CD), 142 ulcerative colitis (UC), 137 female, mean age: 45 ± 11 years, mean time since diagnosis: 10.6 ± 11 years. Twelve patients (4.1%) had a work-disability pension. In addition, 93 (32%) of all patients had an officially recognized disability degree, which was generally moderate (n = 73, 25%) or severe (N = 16, 5%). Age, time since IBD diagnosis, CD, perianal disease, incontinence, active disease, the need for anti-TNF or psychological treatment, previous surgeries and the number of diagnostic tests and medical visits in the previous year were predictors of disability. Major predictors of qualifying for a disability pension were age, IBD activity, incontinence, need for biological drugs and ostomy. Conclusion Mild to moderate work disability is frequent in IBD. However, only a minority of patients develop severe disability qualifying them for a pension. PMID:26279841

  1. Polymorphisms in HLA-DPB1 are associated with differences in rubella virus-specific humoral immunity after vaccination.

    PubMed

    Lambert, Nathaniel D; Haralambieva, Iana H; Kennedy, Richard B; Ovsyannikova, Inna G; Pankratz, Vernon Shane; Poland, Gregory A

    2015-03-15

    Vaccination with live attenuated rubella virus induces a strong immune response in most individuals. However, small numbers of subjects never reach or maintain protective antibody levels, and there is a high degree of variability in immune response. We have previously described genetic polymorphisms in HLA and other candidate genes that are associated with interindividual differences in humoral immunity to rubella virus. To expand our previous work, we performed a genome-wide association study (GWAS) to discover single-nucleotide polymorphisms (SNPs) associated with rubella virus-specific neutralizing antibodies. We identified rs2064479 in the HLA-DPB1 genetic region as being significantly associated with humoral immune response variations after rubella vaccination (P = 8.62 × 10(-8)). All other significant SNPs in this GWAS were located near the HLA-DPB1 gene (P ≤ 1 × 10(-7)). These findings demonstrate that polymorphisms in HLA-DPB1 are strongly associated with interindividual differences in neutralizing antibody levels to rubella vaccination and represent a validation of our previous HLA work. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. [The impact of oral health on daily performance of municipal waste disposal workers in Porto Alegre, Rio Grande do Sul State, Brazil].

    PubMed

    Gomes, Andréa Silveira; Abegg, Claides

    2007-07-01

    This study aimed to investigate the prevalence of oral health impact on daily performance in Brazilian adults. 276 civil servants 35 to 44 years of age from the Public Works and Waste Disposal Department of Porto Alegre, in southern Brazil, were interviewed and clinically examined. Oral Impacts on Daily Performance (OIDP) was used to evaluate the impact of oral health status on daily performance. 73.6% of all subjects had at least one daily performance affected by an oral impact in the previous six months. The most commonly affected performance was eating (48.6%), while the most common symptoms were discomfort (40.6%) and dissatisfaction with one's appearance (31.5%). Missing teeth (21.7%) and toothache (20.7%) were recognized as the main causes of oral impacts on daily performance. OIDP was useful for measuring (physically, psychologically, and socially) the oral impacts on daily performance.

  3. Inequalities in maintenance of health and performance between young adult women and men in higher education.

    PubMed

    Löve, Jesper; Dellve, Lotta; Eklöf, Mats; Hagberg, Mats

    2009-04-01

    Because of ageing populations, most high-income countries are facing an imminent scarcity of labour. Maintenance of health and performance in young adults therefore becomes a crucial prerequisite for sustainable societies. One major obstruction to this accomplishment is the striking health inequalities between young women and young men. Previously these inequalities have mainly been studied in a cross-sectional way, focusing on ill-health. In this study, we compared the prevalence of maintained health and performance between young adult women and men and the predictors for this outcome. The cohort consisted of 1266 participants from a homogenous sample of university students in Sweden. A combined assessment of self-rated 'very good' health and un-impaired performance took place at three time points (i.e. maintained health and performance). Potential predictors covered stable conditions in health-related behaviours, conditions at work/school and work-home interference. Young women had less maintained health and performance than young men. No major differences in predictors were found. However, there was a tendency for psychosocial factors to be the most important predictors, especially in women. That young women had less maintained health and performance in a homogenous sample beyond well-known differentiating factors suggests explanations other than observable structural differences between the sexes. This was also indicated by the importance attached to perceived demands, and work-home interference, especially in women. The combination of less scheduled, and more unscheduled, schoolwork (i.e. time-flexibility) negatively affected the maintenance of health and performance in our study population, suggesting a focus for future studies.

  4. Dipole response of 76Se above 4 MeV

    NASA Astrophysics Data System (ADS)

    Goddard, P. M.; Cooper, N.; Werner, V.; Rusev, G.; Stevenson, P. D.; Rios, A.; Bernards, C.; Chakraborty, A.; Crider, B. P.; Glorius, J.; Ilieva, R. S.; Kelley, J. H.; Kwan, E.; Peters, E. E.; Pietralla, N.; Raut, R.; Romig, C.; Savran, D.; Schnorrenberger, L.; Smith, M. K.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Yates, S. W.

    2013-12-01

    The dipole response of 3476Se in the energy range from 4 to 9 MeV has been analyzed using a (γ⃗,γ') polarized photon scattering technique, performed at the High Intensity γ-Ray Source facility at Triangle Universities Nuclear Laboratory, to complement previous work performed using unpolarized photons. The results of this work offer both an enhanced sensitivity scan of the dipole response and an unambiguous determination of the parities of the observed J=1 states. The dipole response is found to be dominated by E1 excitations, and can reasonably be attributed to a pygmy dipole resonance. Evidence is presented to suggest that a significant amount of directly unobserved excitation strength is present in the region, due to unobserved branching transitions in the decays of resonantly excited states. The dipole response of the region is underestimated when considering only ground state decay branches. We investigate the electric dipole response theoretically, performing calculations in a three-dimensional (3D) Cartesian-basis time-dependent Skyrme-Hartree-Fock framework.

  5. New Whole-House Solutions Case Study: Northwest Energy Efficient Manufactured Housing Program High-Performance Test Homes - Pacific Northwest

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

    None

    2015-05-01

    This project represents the third phase of a multi-year effort to develop and bring to market a High Performance Manufactured Home (HPMH). In this project, the Northwest Energy Efficient Manufactured Housing Program worked with Building America Partnership for Improved Residential Construction and Bonneville Power Administration to help four factory homebuilders build prototype zero energy ready manufactured homes, resulting in what is expected to be a 30% savings relative to the Building America Benchmark. (The actual % savings varies depending on choice of heating equipment and climate zone). Previous phases of this project created a HPMH specification and prototyped individual measuresmore » from the package to obtain engineering approvals and develop preliminary factory construction processes. This case study describes the project team's work during 2014 to build prototype homes to the HPMH specifications and to monitor the homes for energy performance and durability. Monitoring is expected to continue into 2016.« less

  6. Selective epidemic vaccination under the performant routing algorithms

    NASA Astrophysics Data System (ADS)

    Bamaarouf, O.; Alweimine, A. Ould Baba; Rachadi, A.; EZ-Zahraouy, H.

    2018-04-01

    Despite the extensive research on traffic dynamics and epidemic spreading, the effect of the routing algorithms strategies on the traffic-driven epidemic spreading has not received an adequate attention. It is well known that more performant routing algorithm strategies are used to overcome the congestion problem. However, our main result shows unexpectedly that these algorithms favor the virus spreading more than the case where the shortest path based algorithm is used. In this work, we studied the virus spreading in a complex network using the efficient path and the global dynamic routing algorithms as compared to shortest path strategy. Some previous studies have tried to modify the routing rules to limit the virus spreading, but at the expense of reducing the traffic transport efficiency. This work proposed a solution to overcome this drawback by using a selective vaccination procedure instead of a random vaccination used often in the literature. We found that the selective vaccination succeeded in eradicating the virus better than a pure random intervention for the performant routing algorithm strategies.

  7. Effects of nicotine on electroencephalographic (EEG) and behavioural measures of visual working memory in non-smokers during a dual-task paradigm.

    PubMed

    Fisher, Derek J; Knobelsdorf, Amy; Jaworska, Natalia; Daniels, Richelle; Knott, Verner J

    2013-01-01

    Research in smokers has shown that nicotine may have the ability to improve certain aspects of cognitive performance, including working memory and attention, processes which implicate frontal and frontal-parietal brain networks. There is limited research on the cognitive effects of nicotine and their associated neural underpinnings in non-smokers. This study examined the effects of acute nicotine on a working memory task alone or combined with a visual detection task (single- and dual-task conditions) using electroencephalographic (EEG) recordings and behavioural performance measures. Twenty non-smokers (13 females; 7 males) received nicotine gum (6 mg) in a double-blind, randomized, placebo-controlled, repeated measures design. Spectral EEG, together with response speed and accuracy measures, were obtained while participants completed a series of N-Back tasks under single- and dual-task conditions. Nicotine failed to exert any significant effects on performance measures, however, EEG changes were observed, primarily in frontal recordings, which varied with memory load, task condition and hemisphere. These findings, discussed in relation to previous studies in smokers, support the notion that nicotine may modulate central executive systems and contribute to smoking behaviour. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Optimizing immobilized enzyme performance in cell-free environments to produce liquid fuels.

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

    Kumar, Sanat

    The overall goal of this project was to optimize enzyme performance for the production of bio-diesel fuel. Enzyme immobilization has attracted much attention as a means to increase productivity. Mesorporous silica materials have been known to be best suited for immobilizing enzymes. A major challenge is to ensure that the enzymatic activity is retained after immobilization. Two major factors which drive enzymatic deactivation are protein-surface and inter-protein interactions. Previously, we studied protein stability inside pores and how to optimize protein-surface interactions to minimize protein denaturation. In this work we studied eh effect of surface curvature and chemistry on inter-protein interactions.more » Our goal was to find suitable immobilization supports which minimize these inter-protein interactions. Our studies carried out in the frame work of Hydrophobic-Polar (HP) model showed that enzymes immobilized inside hydrophobic pores of optimal sizes are best suited to minimize these inter-protein interactions. Besides, this study is also of biological importance to understand the role of chaperonins in protein disaggregation. Both of these aspects profited immensely with collaborations with our experimental colleague, Prof. Georges Belfort (RPI), who performed the experimental analog of our theoretical works.« less

  9. The impact of cognitive load on delayed recall.

    PubMed

    Camos, Valérie; Portrat, Sophie

    2015-08-01

    Recent studies have suggested that long-term retention of items studied in a working memory span task depends on the refreshing of memory items-more specifically, on the number of refreshing opportunities. However, it was previously shown that refreshing depends on the cognitive load of the concurrent task introduced in the working memory span task. Thus, cognitive load should determine the long-term retention of items assessed in a delayed-recall test if such retention relies on refreshing. In two experiments, while the amount of refreshing opportunities remained constant, we varied the cognitive load of the concurrent task by either introducing tasks differing in their attentional demands or varying the pace of the concurrent task. To verify that this effect was related to refreshing and not to any maintenance mechanism, we also manipulated the availability of subvocal rehearsal. Replicating previous results, increasing cognitive load reduced immediate recall. This increase also had a detrimental effect on delayed recall. Conversely, the addition of concurrent articulation reduced immediate but not delayed recall. This study shows that both working and episodic memory traces depend on the cognitive load of the concurrent task, whereas the use of rehearsal affects only working memory performance. These findings add further evidence of the dissociation between subvocal rehearsal and attentional refreshing.

  10. Usability Flaws in Medication Alerting Systems: Impact on Usage and Work System.

    PubMed

    Marcilly, R; Ammenwerth, E; Roehrer, E; Pelayo, S; Vasseur, F; Beuscart-Zéphir, M-C

    2015-08-13

    Previous research has shown that medication alerting systems face usability issues. There has been no previous attempt to systematically explore the consequences of usability flaws in such systems on users (i.e. usage problems) and work systems (i.e. negative outcomes). This paper aims at exploring and synthesizing the consequences of usability flaws in terms of usage problems and negative outcomes on the work system. A secondary analysis of 26 papers included in a prior systematic review of the usability flaws in medication alerting was performed. Usage problems and negative outcomes were extracted and sorted. Links between usability flaws, usage problems, and negative outcomes were also analyzed. Poor usability generates a large variety of consequences. It impacts the user from a cognitive, behavioral, emotional, and attitudinal perspective. Ultimately, usability flaws have negative consequences on the workflow, the effectiveness of the technology, the medication management process, and, more importantly, patient safety. Only few complete pathways leading from usability flaws to negative outcomes were identified. Usability flaws in medication alerting systems impede users, and ultimately their work system, and negatively impact patient safety. Therefore, the usability dimension may act as a hidden explanatory variable that could explain, at least partly, the (absence of) intended outcomes of new technology.

  11. Usability Flaws in Medication Alerting Systems: Impact on Usage and Work System

    PubMed Central

    Ammenwerth, E.; Roehrer, E.; Pelayo, S.; Vasseur, F.; Beuscart-Zéphir, M.-C.

    2015-01-01

    Summary Objectives Previous research has shown that medication alerting systems face usability issues. There has been no previous attempt to systematically explore the consequences of usability flaws in such systems on users (i.e. usage problems) and work systems (i.e. negative outcomes). This paper aims at exploring and synthesizing the consequences of usability flaws in terms of usage problems and negative outcomes on the work system. Methods A secondary analysis of 26 papers included in a prior systematic review of the usability flaws in medication alerting was performed. Usage problems and negative outcomes were extracted and sorted. Links between usability flaws, usage problems, and negative outcomes were also analyzed. Results Poor usability generates a large variety of consequences. It impacts the user from a cognitive, behavioral, emotional, and attitudinal perspective. Ultimately, usability flaws have negative consequences on the workflow, the effectiveness of the technology, the medication management process, and, more importantly, patient safety. Only few complete pathways leading from usability flaws to negative outcomes were identified. Conclusion Usability flaws in medication alerting systems impede users, and ultimately their work system, and negatively impact patient safety. Therefore, the usability dimension may act as a hidden explanatory variable that could explain, at least partly, the (absence of) intended outcomes of new technology. PMID:26123906

  12. Simulations of Turbulence in Tokamak Edge and Effects of Self-Consistent Zonal Flows

    NASA Astrophysics Data System (ADS)

    Cohen, Bruce; Umansky, Maxim

    2013-10-01

    Progress is reported on simulations of electromagnetic drift-resistive ballooning turbulence in the tokamak edge. This extends previous work to include self-consistent zonal flows and their effects. The previous work addressed simulation of L-mode tokamak edge turbulence using the turbulence code BOUT that solves Braginskii-based plasma fluid equations in tokamak edge domain. The calculations use realistic single-null geometry and plasma parameters of the DIII-D tokamak and produce fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes that compare favorably to experimental data. In the effect of sheared ExB poloidal rotation is included with an imposed static radial electric field fitted to experimental data. In the new work here we include the radial electric field self-consistently driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We present simulations with/without zonal flows for both cylindrical geometry, as in the UCLA Large Plasma Device, and for the DIII-D tokamak L-mode cases in to quantify the influence of self-consistent zonal flows on the microturbulence and the concomitant transport. This work was performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory.

  13. Roofline model toolkit: A practical tool for architectural and program analysis

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

    Lo, Yu Jung; Williams, Samuel; Van Straalen, Brian

    We present preliminary results of the Roofline Toolkit for multicore, many core, and accelerated architectures. This paper focuses on the processor architecture characterization engine, a collection of portable instrumented micro benchmarks implemented with Message Passing Interface (MPI), and OpenMP used to express thread-level parallelism. These benchmarks are specialized to quantify the behavior of different architectural features. Compared to previous work on performance characterization, these microbenchmarks focus on capturing the performance of each level of the memory hierarchy, along with thread-level parallelism, instruction-level parallelism and explicit SIMD parallelism, measured in the context of the compilers and run-time environments. We also measuremore » sustained PCIe throughput with four GPU memory managed mechanisms. By combining results from the architecture characterization with the Roofline model based solely on architectural specifications, this work offers insights for performance prediction of current and future architectures and their software systems. To that end, we instrument three applications and plot their resultant performance on the corresponding Roofline model when run on a Blue Gene/Q architecture.« less

  14. A Comparison of Evaluation Metrics for Biomedical Journals, Articles, and Websites in Terms of Sensitivity to Topic

    PubMed Central

    Fu, Lawrence D.; Aphinyanaphongs, Yindalon; Wang, Lily; Aliferis, Constantin F.

    2011-01-01

    Evaluating the biomedical literature and health-related websites for quality are challenging information retrieval tasks. Current commonly used methods include impact factor for journals, PubMed’s clinical query filters and machine learning-based filter models for articles, and PageRank for websites. Previous work has focused on the average performance of these methods without considering the topic, and it is unknown how performance varies for specific topics or focused searches. Clinicians, researchers, and users should be aware when expected performance is not achieved for specific topics. The present work analyzes the behavior of these methods for a variety of topics. Impact factor, clinical query filters, and PageRank vary widely across different topics while a topic-specific impact factor and machine learning-based filter models are more stable. The results demonstrate that a method may perform excellently on average but struggle when used on a number of narrower topics. Topic adjusted metrics and other topic robust methods have an advantage in such situations. Users of traditional topic-sensitive metrics should be aware of their limitations. PMID:21419864

  15. A multidisciplinary approach of workload assessment in real-job situations: investigation in the field of aerospace activities

    PubMed Central

    Mélan, Claudine; Cascino, Nadine

    2014-01-01

    The present contribution presents two field studies combining tools and methods from cognitive psychology and from occupational psychology in order to perform a thorough investigation of workload in employees. Cognitive load theory proposes to distinguish different load categories of working memory, in a context of instruction. Intrinsic load is inherent to the task, extraneous load refers to components of a learning environment that may be modified to reduce total load, and germane load enables schemas construction and thus efficient learning. We showed previously that this theoretical framework may be successfully extended to working memory tasks in non-instructional designs. Other theoretical models, issued from the field of occupational psychology, account for an individual’s perception of work demands or requirements in the context of different psychosocial features of the (work) environment. Combining these approaches is difficult as workload assessment by job-perception questionnaires explore an individual’s overall job-perception over a large time-period, whereas cognitive load investigations in working memory tasks are typically performed within short time-periods. We proposed an original methodology enabling investigation of workload and load factors in a comparable time-frame. We report two field studies investigating workload on different shift-phases and between work-shifts, with two custom-made tools. The first one enabled workload assessment by manipulating intrinsic load (task difficulty) and extraneous load (time pressure) in a working-memory task. The second tool was a questionnaire based on the theoretical concepts of work-demands, control, and psychosocial support. Two additional dimensions suspected to contribute to job-perception, i.e., work–family conflicts and availability of human and technical resources were also explored. Results of workload assessments were discussed in light of operators’ alertness and job-performance. PMID:25232346

  16. Modeling spanwise nonuniformity in the cross-sectional analysis of composite beams

    NASA Astrophysics Data System (ADS)

    Ho, Jimmy Cheng-Chung

    Spanwise nonuniformity effects are modeled in the cross-sectional analysis of beam theory. This modeling adheres to an established numerical framework on cross-sectional analysis of uniform beams with arbitrary cross-sections. This framework is based on two concepts: decomposition of the rotation tensor and the variational-asymptotic method. Allowance of arbitrary materials and geometries in the cross-section is from discretization of the warping field by finite elements. By this approach, dimensional reduction from three-dimensional elasticity is performed rigorously and the sectional strain energy is derived to be asymptotically-correct. Elastic stiffness matrices are derived for inputs into the global beam analysis. Recovery relations for the displacement, stress, and strain fields are also derived with care to be consistent with the energy. Spanwise nonuniformity effects appear in the form of pointwise and sectionwise derivatives, which are approximated by finite differences. The formulation also accounts for the effects of spanwise variations in initial twist and/or curvature. A linearly tapered isotropic strip is analyzed to demonstrate spanwise nonuniformity effects on the cross-sectional analysis. The analysis is performed analytically by the variational-asymptotic method. Results from beam theory are validated against solutions from plane stress elasticity. These results demonstrate that spanwise nonuniformity effects become significant as the rate at which the cross-sections vary increases. The modeling of transverse shear modes of deformation is accomplished by transforming the strain energy into generalized Timoshenko form. Approximations in this transformation procedure from previous works, when applied to uniform beams, are identified. The approximations are not used in the present work so as to retain more accuracy. Comparison of present results with those previously published shows that these approximations sometimes change the results measurably and thus are inappropriate. Static and dynamic results, from the global beam analysis, are calculated to show the differences between using stiffness constants from previous works and the present work. As a form of validation of the transformation procedure, calculations from the global beam analysis of initially twisted isotropic beams from using curvilinear coordinate axes featuring twist are shown to be equivalent to calculations using Cartesian coordinates.

  17. Reaction Times to Consecutive Automation Failures: A Function of Working Memory and Sustained Attention.

    PubMed

    Jipp, Meike

    2016-12-01

    This study explored whether working memory and sustained attention influence cognitive lock-up, which is a delay in the response to consecutive automation failures. Previous research has demonstrated that the information that automation provides about failures and the time pressure that is associated with a task influence cognitive lock-up. Previous research has also demonstrated considerable variability in cognitive lock-up between participants. This is why individual differences might influence cognitive lock-up. The present study tested whether working memory-including flexibility in executive functioning-and sustained attention might be crucial in this regard. Eighty-five participants were asked to monitor automated aircraft functions. The experimental manipulation consisted of whether or not an initial automation failure was followed by a consecutive failure. Reaction times to the failures were recorded. Participants' working-memory and sustained-attention abilities were assessed with standardized tests. As expected, participants' reactions to consecutive failures were slower than their reactions to initial failures. In addition, working-memory and sustained-attention abilities enhanced the speed with which participants reacted to failures, more so with regard to consecutive than to initial failures. The findings highlight that operators with better working memory and sustained attention have small advantages when initial failures occur, but their advantages increase across consecutive failures. The results stress the need to consider personnel selection strategies to mitigate cognitive lock-up in general and training procedures to enhance the performance of low ability operators. © 2016, Human Factors and Ergonomics Society.

  18. The impact of bilingualism on working memory in pediatric epilepsy

    PubMed Central

    Veenstra, Amy L.; Riley, Jeffrey D.; Barrett, Lauren E.; Muhonen, Michael G.; Zupanc, Mary; Romain, Jonathan E.; Lin, Jack J.; Mucci, Grace

    2016-01-01

    Impairments in executive skills broadly span across multiple childhood epilepsy syndromes and can adversely affect quality of life. Bilingualism has been previously shown to correlate with enhanced executive functioning in healthy individuals. This study seeks to determine whether the bilingual advantage in executive functioning exists in the context of pediatric epilepsy. We retrospectively analyzed neuropsychological data in 52 children with epilepsy and compared executive function scores in monolingual versus bilingual children with epilepsy, while controlling for socioeconomic status and ethnicity. Bilingual children performed significantly better on the Working Memory scale than did monolingual children. There were no significant differences on the remaining executive function variables. The bilingual advantage appears to persist for working memory in children with epilepsy. These findings suggest that bilingualism is potentially a protective variable in the face of epilepsy-related working memory dysfunction. PMID:26720703

  19. Multithreaded implicitly dealiased convolutions

    NASA Astrophysics Data System (ADS)

    Roberts, Malcolm; Bowman, John C.

    2018-03-01

    Implicit dealiasing is a method for computing in-place linear convolutions via fast Fourier transforms that decouples work memory from input data. It offers easier memory management and, for long one-dimensional input sequences, greater efficiency than conventional zero-padding. Furthermore, for convolutions of multidimensional data, the segregation of data and work buffers can be exploited to reduce memory usage and execution time significantly. This is accomplished by processing and discarding data as it is generated, allowing work memory to be reused, for greater data locality and performance. A multithreaded implementation of implicit dealiasing that accepts an arbitrary number of input and output vectors and a general multiplication operator is presented, along with an improved one-dimensional Hermitian convolution that avoids the loop dependency inherent in previous work. An alternate data format that can accommodate a Nyquist mode and enhance cache efficiency is also proposed.

  20. Explicit processing demands reveal language modality-specific organization of working memory.

    PubMed

    Rudner, Mary; Rönnberg, Jerker

    2008-01-01

    The working memory model for Ease of Language Understanding (ELU) predicts that processing differences between language modalities emerge when cognitive demands are explicit. This prediction was tested in three working memory experiments with participants who were Deaf Signers (DS), Hearing Signers (HS), or Hearing Nonsigners (HN). Easily nameable pictures were used as stimuli to avoid confounds relating to sensory modality. Performance was largely similar for DS, HS, and HN, suggesting that previously identified intermodal differences may be due to differences in retention of sensory information. When explicit processing demands were high, differences emerged between DS and HN, suggesting that although working memory storage in both groups is sensitive to temporal organization, retrieval is not sensitive to temporal organization in DS. A general effect of semantic similarity was also found. These findings are discussed in relation to the ELU model.

  1. Age differences in spatial working memory contributions to visuomotor adaptation and transfer.

    PubMed

    Langan, Jeanne; Seidler, Rachael D

    2011-11-20

    Throughout our life span we encounter challenges that require us to adapt to the demands of our changing environment; this entails learning new skills. Two primary components of motor skill learning are motor acquisition, the initial process of learning the skill, and motor transfer, when learning a new skill is benefitted by the overlap with a previously learned one. Older adults typically exhibit declines in motor acquisition compared to young adults, but remarkably, do not demonstrate deficits in motor transfer [10]. Our recent work demonstrates that a failure to engage spatial working memory (SWM) is associated with skill learning deficits in older adults [16]. Here, we investigate the role that SWM plays in both motor learning and transfer in young and older adults. Both age groups exhibited performance savings, or positive transfer, at transfer of learning for some performance variables. Measures of spatial working memory performance and reaction time correlated with both motor learning and transfer for young adults. Young adults recruited overlapping brain regions in prefrontal, premotor, parietal and occipital cortex for performance of a SWM and a visuomotor adaptation task, most notably during motor learning, replicating our prior findings [12]. Neural overlap between the SWM task and visuomotor adaptation for the older adults was limited to parietal cortex, with minimal changes from motor learning to transfer. Combined, these results suggest that age differences in engagement of cognitive strategies have a differential impact on motor learning and transfer. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Age differences in spatial working memory contributions to visuomotor adaptation and transfer

    PubMed Central

    Langan, Jeanne; Seidler, Rachael. D.

    2011-01-01

    Throughout our life span we encounter challenges that require us to adapt to the demands of our changing environment; this entails learning new skills. Two primary components of motor skill learning are motor acquisition, the initial process of learning the skill, and motor transfer, when learning a new skill is benefitted by the overlap with a previously learned one. Older adults typically exhibit declines in motor acquisition compared to young adults, but remarkably, do not demonstrate deficits in motor transfer (Seidler, 2007). Our recent work demonstrates that a failure to engage spatial working memory (SWM) is associated with skill learning deficits in older adults (Anguera et al., 2011). Here, we investigate the role that SWM plays in both motor learning and transfer in young and older adults. Both age groups exhibited performance savings, or positive transfer, at transfer of learning for some performance variables. Measures of spatial working memory performance and reaction time correlated with both motor learning and transfer for young adults. Young adults recruited overlapping brain regions in prefrontal, premotor, parietal and occipital cortex for performance of a SWM and a visuomotor adaptation task, most notably during motor learning, replicating our prior findings (Anguera et al., 2010). Neural overlap between the SWM task and visuomotor adaptation for the older adults was limited to parietal cortex, with minimal changes from motor learning to transfer. Combined, these results suggest that age differences in engagement of cognitive strategies have a differential impact on motor learning and transfer. PMID:21784106

  3. Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

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

    Aab, A.; Abreu, P.; Andringa, S.

    2017-06-01

    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80{sup o} and energies in excess of 4 EeV (4 × 10{sup 18} eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providingmore » directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding p -values obtained after accounting for searches blindly performed at several angular scales, are 1.3 × 10{sup −5} in the case of the angular power spectrum, and 2.5 × 10{sup −3} in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.« less

  4. Functional MRI of Handwriting Tasks: A Study of Healthy Young Adults Interacting with a Novel Touch-Sensitive Tablet

    PubMed Central

    Karimpoor, Mahta; Churchill, Nathan W.; Tam, Fred; Fischer, Corinne E.; Schweizer, Tom A.; Graham, Simon J.

    2018-01-01

    Handwriting is a complex human activity that engages a blend of cognitive and visual motor skills. Current understanding of the neural correlates of handwriting has largely come from lesion studies of patients with impaired handwriting. Task-based fMRI studies would be useful to supplement this work. To address concerns over ecological validity, previously we developed a fMRI-compatible, computerized tablet system for writing and drawing including visual feedback of hand position and an augmented reality display. The purpose of the present work is to use the tablet system in proof-of-concept to characterize brain activity associated with clinically relevant handwriting tasks, originally developed to characterize handwriting impairments in Alzheimer’s disease patients. As a prelude to undertaking fMRI studies of patients, imaging was performed of twelve young healthy subjects who copied sentences, phone numbers, and grocery lists using the fMRI-compatible tablet. Activation maps for all handwriting tasks consisted of a distributed network of regions in reasonable agreement with previous studies of handwriting performance. In addition, differences in brain activity were observed between the test subcomponents consistent with different demands of neural processing for successful task performance, as identified by investigating three quantitative behavioral metrics (writing speed, stylus contact force and stylus in air time). This study provides baseline behavioral and brain activity results for fMRI studies that adopt this handwriting test to characterize patients with brain impairments. PMID:29487511

  5. Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

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

    Aab, A.; Abreu, P.; Aglietta, M.

    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80(o) and energies in excess of 4 EeV (4 × 10 18 eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information onmore » any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured, while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding p-values obtained after accounting for searches blindly performed at several angular scales, are 1.3 × 10 -5 in the case of the angular power spectrum, and 2.5 × 10 -3 in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.« less

  6. Functional MRI of Handwriting Tasks: A Study of Healthy Young Adults Interacting with a Novel Touch-Sensitive Tablet.

    PubMed

    Karimpoor, Mahta; Churchill, Nathan W; Tam, Fred; Fischer, Corinne E; Schweizer, Tom A; Graham, Simon J

    2018-01-01

    Handwriting is a complex human activity that engages a blend of cognitive and visual motor skills. Current understanding of the neural correlates of handwriting has largely come from lesion studies of patients with impaired handwriting. Task-based fMRI studies would be useful to supplement this work. To address concerns over ecological validity, previously we developed a fMRI-compatible, computerized tablet system for writing and drawing including visual feedback of hand position and an augmented reality display. The purpose of the present work is to use the tablet system in proof-of-concept to characterize brain activity associated with clinically relevant handwriting tasks, originally developed to characterize handwriting impairments in Alzheimer's disease patients. As a prelude to undertaking fMRI studies of patients, imaging was performed of twelve young healthy subjects who copied sentences, phone numbers, and grocery lists using the fMRI-compatible tablet. Activation maps for all handwriting tasks consisted of a distributed network of regions in reasonable agreement with previous studies of handwriting performance. In addition, differences in brain activity were observed between the test subcomponents consistent with different demands of neural processing for successful task performance, as identified by investigating three quantitative behavioral metrics (writing speed, stylus contact force and stylus in air time). This study provides baseline behavioral and brain activity results for fMRI studies that adopt this handwriting test to characterize patients with brain impairments.

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

    Guo, D.; Akis, R.; Brinkman, D.

    An improved model of copper p-type doping in CdTe absorbers is proposed that accounts for the mechanisms related to tightly bound Cu(i)-Cu(Cd) and Cd(i)-Cu(Cd) complexes that both limit diffusion and cause self-compensation of Cu species. The new model explains apparent discrepancy between DFT-calculated and fitted diffusion parameters of Cu reported in our previous work, and allows for better understanding of performance and metastabilities in CdTe PV devices.

  8. The Military Immunization Communication Handbook

    DTIC Science & Technology

    2005-09-01

    the persistent contention that thimerosal, a preservative in some vaccines , causes autism in children. In July 2005, senior scientists from a variety... autism . Acting out of caution, however, these same groups agreed with FDA’s previous decision to discontinue the use of thimerosal in vaccines . The press...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Army Surgeon General’s Office,Military Vaccine (MILVAX) Agency

  9. Example-Based Learning: Effects of Different Types of Examples on Student Performance, Cognitive Load and Self-Efficacy in a Statistical Learning Task

    ERIC Educational Resources Information Center

    Huang, Xiaoxia

    2017-01-01

    Previous research has indicated the disconnect between example-based research focusing on worked examples (WEs) and that focusing on modeling examples. The purpose of this study was to examine and compare the effect of four different types of examples from the two separate lines of research, including standard WEs, erroneous WEs, expert (masterly)…

  10. Broadband Scattering from Sand and Sand/Mud Sediments with Extensive Environmental Characterization

    DTIC Science & Technology

    2017-01-30

    experiment , extensive envi- ronmental characterization was also performed to support data/model comparisons for both experimental efforts. The site...mechanisms, potentially addressing questions left unresolved from the previous sediment acoustics experiments , SAX99 and SAX04. This work was also to provide...environmental characterization to support the analysis of data collected during the Target and Reverberation Experiment in 2013 (TREX13) as well as

  11. Inhalability for aerosols at ultra-low windspeeds

    NASA Astrophysics Data System (ADS)

    Sleeth, Darrah K.; Vincent, James H.

    2009-02-01

    Most previous experimental studies of aerosol inhalability were conducted in wind tunnels for windspeeds greater than 0.5 ms-1. While that body of work was used to establish a convention for the inhalable fraction, results from studies in calm air chambers (for essentially zero windspeed) are being discussed as the basis of a modified criterion. However, information is lacking for windspeeds in the intermediate range, which - it so happens - pertain to most actual workplaces. With this in mind, we have developed a new experimental system to assess inhalability - and, ultimately, personal sampler performance - for aerosols with particle aerodynamic diameter within the range from about 9 to 90 μm for ultra-low windspeed environments from about 0.1 to 0.5 ms1. This new system contains an aerosol test facility, fully described elsewhere, that combines the physical attributes and performance characteristics of moving air wind tunnels and calm air chambers, both of which have featured individually in previous research. It also contains a specially-designed breathing, heated, life-sized mannequin that allows for accurate recovery of test particulate material that has been inhaled. Procedures have been developed that employ test aerosols of well-defined particle size distribution generated mechanically from narrowly-graded powders of fused alumina. Using this new system, we have conducted an extensive set of new experiments to measure the inhalability of a human subject (as represented by the mannequin), aimed at filling the current knowledge gap for conditions that are more realistic than those embodied in most previous research. These data reveal that inhalability throughout the range of interest is significantly different based on windspeed, indicating a rise in aspiration efficiency as windspeed decreases. Breathing flowrate and mode of breathing (i.e. nose versus mouth breathing) did not show significant differences for the inhalability of aerosols. On the whole however, the data obtained here are within the range of inhalability data that exist from the large body of the previous experimental work performed at the higher windspeeds. These latest findings are an important contribution to the ongoing discussion in international standards-setting bodies about the possible adjustment of the quantitative definition of what constitutes the inhalable fraction.

  12. Competition between frontoparietal control and default networks supports social working memory and empathy

    PubMed Central

    Xin, Fei

    2015-01-01

    An extensive body of literature has indicated that there is increased activity in the frontoparietal control network (FPC) and decreased activity in the default mode network (DMN) during working memory (WM) tasks. The FPC and DMN operate in a competitive relationship during tasks requiring externally directed attention. However, the association between this FPC-DMN competition and performance in social WM tasks has rarely been reported in previous studies. To investigate this question, we measured FPC-DMN connectivity during resting state and two emotional face recognition WM tasks using the 2-back paradigm. Thirty-four individuals were instructed to perform the tasks based on either the expression [emotion (EMO)] or the identity (ID) of the same set of face stimuli. Consistent with previous studies, an increased anti-correlation between the FPC and DMN was observed during both tasks relative to the resting state. Specifically, this anti-correlation during the EMO task was stronger than during the ID task, as the former has a higher social load. Intriguingly, individual differences in self-reported empathy were significantly correlated with the FPC-DMN anti-correlation in the EMO task. These results indicate that the top-down signals from the FPC suppress the DMN to support social WM and empathy. PMID:25556209

  13. Optimization of Well Configuration for a Sedimentary Enhanced Geothermal Reservoir

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

    Zhou, Mengnan; Cho, JaeKyoung; Zerpa, Luis E.

    The extraction of geothermal energy in the form of hot water from sedimentary rock formations could expand the current geothermal energy resources toward new regions. From previous work, we observed that sedimentary geothermal reservoirs with relatively low permeability would require the application of enhancement techniques (e.g., well hydraulic stimulation) to achieve commercial production/injection rates. In this paper we extend our previous work to develop a methodology to determine the optimum well configuration that maximizes the hydraulic performance of the geothermal system. The geothermal systems considered consist of one vertical well doublet system with hydraulic fractures, and three horizontal well configurationsmore » with open-hole completion, longitudinal fractures and transverse fractures, respectively. A commercial thermal reservoir simulation is used to evaluate the geothermal reservoir performance using as design parameters the well spacing and the length of the horizontal wells. The results obtained from the numerical simulations are used to build a response surface model based on the multiple linear regression method. The optimum configuration of the sedimentary geothermal systems is obtained from the analysis of the response surface model. The proposed methodology is applied to a case study based on a reservoir model of the Lyons sandstone formation, located in the Wattenberg field, Denver-Julesburg basin, Colorado.« less

  14. The AMT maglev test sled -- EML weapons technology transition to transportation

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

    Schaaf, J.C. Jr.; Zowarka, R.C. Jr.; Davey, K.

    1997-01-01

    Technology spinoffs from prior electromagnetic launcher work enhance a magnetic levitation transportation system test bed being developed by American Maglev Technology of Florida. This project uses a series wound linear DC motor and brushes to simplify the magnetic levitation propulsion system. It takes advantage of previous related work in electromagnetic launcher technology to achieve success with this innovative design. Technology and knowledge gained from developments for homopolar generators and proposed railgun arc control are key to successful performance. This contribution supports a cost effective design that is competitive with alternative concepts. Brushes transfer power from the guideway (rail) to themore » vehicle (armature) in a novel design that activates the guideway only under the vehicle, reducing power losses and guideway construction costs. The vehicle carries no power for propulsion and levitation, and acts only as a conduit for the power through the high speed brushes. Brush selection and performance is based on previous EML homopolar generator research. A counterpulse circuit, first introduced in an early EML conference, is used to suppress arcing on the trailing brush and to transfer inductive energy to the next propulsion coil. Isolated static lift and preliminary propulsion tests have been completed, and integrated propulsion and lift tests are scheduled in early 1996.« less

  15. Improving fluid intelligence with training on working memory.

    PubMed

    Jaeggi, Susanne M; Buschkuehl, Martin; Jonides, John; Perrig, Walter J

    2008-05-13

    Fluid intelligence (Gf) refers to the ability to reason and to solve new problems independently of previously acquired knowledge. Gf is critical for a wide variety of cognitive tasks, and it is considered one of the most important factors in learning. Moreover, Gf is closely related to professional and educational success, especially in complex and demanding environments. Although performance on tests of Gf can be improved through direct practice on the tests themselves, there is no evidence that training on any other regimen yields increased Gf in adults. Furthermore, there is a long history of research into cognitive training showing that, although performance on trained tasks can increase dramatically, transfer of this learning to other tasks remains poor. Here, we present evidence for transfer from training on a demanding working memory task to measures of Gf. This transfer results even though the trained task is entirely different from the intelligence test itself. Furthermore, we demonstrate that the extent of gain in intelligence critically depends on the amount of training: the more training, the more improvement in Gf. That is, the training effect is dosage-dependent. Thus, in contrast to many previous studies, we conclude that it is possible to improve Gf without practicing the testing tasks themselves, opening a wide range of applications.

  16. Improving fluid intelligence with training on working memory

    PubMed Central

    Jaeggi, Susanne M.; Buschkuehl, Martin; Jonides, John; Perrig, Walter J.

    2008-01-01

    Fluid intelligence (Gf) refers to the ability to reason and to solve new problems independently of previously acquired knowledge. Gf is critical for a wide variety of cognitive tasks, and it is considered one of the most important factors in learning. Moreover, Gf is closely related to professional and educational success, especially in complex and demanding environments. Although performance on tests of Gf can be improved through direct practice on the tests themselves, there is no evidence that training on any other regimen yields increased Gf in adults. Furthermore, there is a long history of research into cognitive training showing that, although performance on trained tasks can increase dramatically, transfer of this learning to other tasks remains poor. Here, we present evidence for transfer from training on a demanding working memory task to measures of Gf. This transfer results even though the trained task is entirely different from the intelligence test itself. Furthermore, we demonstrate that the extent of gain in intelligence critically depends on the amount of training: the more training, the more improvement in Gf. That is, the training effect is dosage-dependent. Thus, in contrast to many previous studies, we conclude that it is possible to improve Gf without practicing the testing tasks themselves, opening a wide range of applications. PMID:18443283

  17. A cognitive-behavioural analysis of mental toughness in national rugby league football teams.

    PubMed

    Golby, Jim; Sheard, Michael; Lavallee, David

    2003-04-01

    This study examined the relations between demographic characteristics of rugby players and selected aspects of psychological performance in rugby league football. Mental toughness was assessed using Psychological Performance Inventory and Hardiness on the Personal Views Survey III-R. Participants (N=70) were international rugby league footballers representing four teams (Wales, France, Ireland, England) in the 2000 Rugby League World Cup. Participants completed the questionnaires in training camp. Welsh-nationality players had a significantly higher mean score on two of the hardiness subscales. Hardiness measures displayed the greatest and most frequently statistically significant differences. The findings concur with previous work indicating superior hardiness is related to improved performance in sports.

  18. Measuring Constraint-Set Utility for Partitional Clustering Algorithms

    NASA Technical Reports Server (NTRS)

    Davidson, Ian; Wagstaff, Kiri L.; Basu, Sugato

    2006-01-01

    Clustering with constraints is an active area of machine learning and data mining research. Previous empirical work has convincingly shown that adding constraints to clustering improves the performance of a variety of algorithms. However, in most of these experiments, results are averaged over different randomly chosen constraint sets from a given set of labels, thereby masking interesting properties of individual sets. We demonstrate that constraint sets vary significantly in how useful they are for constrained clustering; some constraint sets can actually decrease algorithm performance. We create two quantitative measures, informativeness and coherence, that can be used to identify useful constraint sets. We show that these measures can also help explain differences in performance for four particular constrained clustering algorithms.

  19. A Novel Switching-Based Control Framework for Improved Task Performance in Teleoperation System With Asymmetric Time-Varying Delays.

    PubMed

    Zhai, Di-Hua; Xia, Yuanqing

    2018-02-01

    This paper addresses the adaptive control for task-space teleoperation systems with constrained predefined synchronization error, where a novel switched control framework is investigated. Based on multiple Lyapunov-Krasovskii functionals method, the stability of the resulting closed-loop system is established in the sense of state-independent input-to-output stability. Compared with previous work, the developed method can simultaneously handle the unknown kinematics/dynamics, asymmetric varying time delays, and prescribed performance control in a unified framework. It is shown that the developed controller can guarantee the prescribed transient-state and steady-state synchronization performances between the master and slave robots, which is demonstrated by the simulation study.

  20. Regeneratively cooled rocket engine for space storable propellants

    NASA Technical Reports Server (NTRS)

    Wagner, W. R.

    1973-01-01

    Analysis, design, fabrication, and test efforts were performed for the existing OF2/B2H6 regeneratively cooled lK (4448 N) thrust chamber to illustrate simultaneous B2H6 fuel and OF2 oxidizer cooling and to provide results for a gaseous propellant condition injected into the combustion chamber. Data derived from performance, thermal and flow measurements confirmed predictions derived from previous test work and from concurrent analytical study. Development data derived from the experimental study were indicated to be sufficient to develop a preflight thrust chamber demonstrator prototype for future space mission objectives.

  1. Autologous conditioned plasma as therapy of tendon and ligament lesions in seven horses

    PubMed Central

    Georg, Rindermann; Maria, Cislakova; Gisela, Arndt

    2010-01-01

    This case report describes the intralesional application of autologous conditioned plasma (ACP) in seven horses as treatment of severe tendinitis of the superficial digital flexor tendon, deep digital flexor tendon, or desmitis of the inferior check ligament. Follow-up data of the horses revealed a positive outcome in 10 to 13 months post injury. All horses treated with ACP were either performing in their previous work-load or were back in full training. Further studies with long-term follow-up will have to be performed to support these clinical intermediate-term observations. PMID:20458161

  2. Single cell array impedance analysis in a microfluidic device

    NASA Astrophysics Data System (ADS)

    Altinagac, Emre; Taskin, Selen; Kizil, Huseyin

    2016-10-01

    Impedance analysis of single cells is presented in this paper. Following the separation of a target cell type by dielectrophoresis in our previous work, this paper focuses on capturing the cells as a single array and performing impedance analysis to point out the signature difference between each cell type. Lab-on-a-chip devices having a titanium interdigitated electrode layer on a glass substrate and a PDMS microchannel are fabricated to capture each cell in a single form and perform impedance analysis. HCT116 (homosapiens colon colorectal carcin) and HEK293 (human embryonic kidney) cells are used in our experiments.

  3. Pollen and mold exposure impairs the work performance of employees with allergic rhinitis.

    PubMed

    Kessler, R C; Almeida, D M; Berglund, P; Stang, P

    2001-10-01

    Although quality of life studies suggest that allergic rhinitis has a substantial impact on work impairment, national survey estimates of the magnitude of this impairment have varied widely. Retrospective recall bias is likely to be a major cause of this variability. This study used a nationally representative daily diary sample to obtain prospective data that improve on previous estimates of the work impairment because of allergic rhinitis. The MacArthur Foundation National Survey of Daily Experience is a daily diary survey that included a nationally representative subsample of 739 employed people, each of whom provided daily reports on work performance for 1 randomly assigned week of the calendar year. National Allergy Bureau monitoring station data were merged with the survey data to study the association of time-space variation in pollen/mold exposure with impaired daily work quality and quantity. National Allergy Bureau pollen/mold counts are significantly related to work impairments only among respondents with self-reported allergic rhinitis. The average estimated monthly salary-equivalent work impairment costs associated with pollen/mold exposure for each allergy sufferer is between $109 and $156, with an annualized national projection of between $5.4 billion and $7.7 billion. The extent to which these costs can be recovered by increasing the proportion of allergy sufferers who are successfully treated remains unknown and can only be evaluated definitively in effectiveness trials.

  4. Performance Engineering Research Institute SciDAC-2 Enabling Technologies Institute Final Report

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

    Lucas, Robert

    2013-04-20

    Enhancing the performance of SciDAC applications on petascale systems had high priority within DOE SC at the start of the second phase of the SciDAC program, SciDAC-2, as it continues to do so today. Achieving expected levels of performance on high-end computing (HEC) systems is growing ever more challenging due to enormous scale, increasing architectural complexity, and increasing application complexity. To address these challenges, the University of Southern California?s Information Sciences Institute organized the Performance Engineering Research Institute (PERI). PERI implemented a unified, tripartite research plan encompassing: (1) performance modeling and prediction; (2) automatic performance tuning; and (3) performance engineeringmore » of high profile applications. Within PERI, USC?s primary research activity was automatic tuning (autotuning) of scientific software. This activity was spurred by the strong user preference for automatic tools and was based on previous successful activities such as ATLAS, which automatically tuned components of the LAPACK linear algebra library, and other recent work on autotuning domain-specific libraries. Our other major component was application engagement, to which we devoted approximately 30% of our effort to work directly with SciDAC-2 applications. This report is a summary of the overall results of the USC PERI effort.« less

  5. The Composer's Program Note for Newly Written Classical Music: Content and Intentions.

    PubMed

    Blom, Diana M; Bennett, Dawn; Stevenson, Ian

    2016-01-01

    In concerts of western classical music the provision of a program note is a widespread practice dating back to the 18th century and still commonly in use. Program notes tend to inform listeners and performers about historical context, composer biographical details, and compositional thinking. However, the scant program note research conducted to date reveals that program notes may not foster understanding or enhance listener enjoyment as previously assumed. In the case of canonic works, performers and listeners may already be familiar with much of the program note information. This is not so in the case of newly composed works, which formed the basis of the exploratory study reported here. This article reports the views of 17 living contemporary composers on their writing of program notes for their own works. In particular, the study sought to understand the intended recipient, role and the content of composer-written program notes. Participating composers identified three main roles for their program notes: to shape a performer's interpretation of the work; to guide, engage or direct the listener and/or performer; and as collaborative mode of communication between the composer, performer, and listener. For some composers, this collaboration was intended to result in "performative listening" in which listeners were actively engaged in bringing each composition to life. This was also described as a form of empathy that results in the co-construction of the musical experience. Overall, composers avoided giving too much personal information and they provided performers with more structural information. However, composers did not agree on whether the same information should be provided to both performers and listeners. Composers' responses problematize the view of a program note as a simple statement from writer to recipient, indicating instead a more complex set of relations at play between composer, performer, listener, and the work itself. These relations are illustrated in a model. There are implications for program note writers and readers, and for educators. Future research might seek to enhance understanding of program notes, including whether the written program note is the most effective format for communications about music.

  6. Working conditions in call-centers, the impact on employee health: a transversal study. Part II.

    PubMed

    Charbotel, Barbara; Croidieu, Sophie; Vohito, Michel; Guerin, Anne-Céline; Renaud, Liliane; Jaussaud, Joelle; Bourboul, Christian; Imbard, Isabelle; Ardiet, Dominique; Bergeret, Alain

    2009-05-01

    The present study sought to assess the impact of telephone call center employees' working conditions on health by identifying at-risk employment situations. A transversal study was performed in companies followed by 47 occupational physicians taking part (working conditions have been previously described). A self-administered medical questionnaire was used to collect data on absence due to sick leave, hearing and visual problems, musculoskeletal disorders, psychotropic drug use, etc. An analog-scale self-assessment of health status and a general health questionnaire (GHQ-12) were used. Personal or familial events that might underlie health problems and affect GHQ-12 results were quantified and taken into account in a logistic regression. A total of 2,130 call-handlers were included. Workers who had availed sick leave during the previous 12 months were 60%. The most frequent musculoskeletal complaints over the previous 12-month period concerned the cervical region (59%). During the same period, 77.3% of subjects experienced visual fatigue, 50% reported auditory fatigue signs and 47% vocal disturbance or fatigue. According to the Likert scale, 39.4% of workers had showed psychological distress. Almost 24% of the workers had used psychoactive medication during the previous 12 months. A significant association was found between psychological distress and the frequency of musculoskeletal disorders. Psychological distress and musculoskeletal disorders were significantly greater in workers with Job Strain and Iso Strain. After taking non-occupational factors into account, some occupational factors were found to increase the risk of psychological distress (Likert >12): imposed full-time schedule, being unable to simultaneously meet both quality and quantity requirements, situations of tension with clients, negative comments from superiors, and lack of recognition from superiors. This survey of over 2,000 call center employees highlighted the high frequency of psychological distress in this population and the health impact of working conditions.

  7. Performance analysis of wireless sensor networks in geophysical sensing applications

    NASA Astrophysics Data System (ADS)

    Uligere Narasimhamurthy, Adithya

    Performance is an important criteria to consider before switching from a wired network to a wireless sensing network. Performance is especially important in geophysical sensing where the quality of the sensing system is measured by the precision of the acquired signal. Can a wireless sensing network maintain the same reliability and quality metrics that a wired system provides? Our work focuses on evaluating the wireless GeoMote sensor motes that were developed by previous computer science graduate students at Mines. Specifically, we conducted a set of experiments, namely WalkAway and Linear Array experiments, to characterize the performance of the wireless motes. The motes were also equipped with the Sticking Heartbeat Aperture Resynchronization Protocol (SHARP), a time synchronization protocol developed by a previous computer science graduate student at Mines. This protocol should automatically synchronize the mote's internal clocks and reduce time synchronization errors. We also collected passive data to evaluate the response of GeoMotes to various frequency components associated with the seismic waves. With the data collected from these experiments, we evaluated the performance of the SHARP protocol and compared the performance of our GeoMote wireless system against the industry standard wired seismograph system (Geometric-Geode). Using arrival time analysis and seismic velocity calculations, we set out to answer the following question. Can our wireless sensing system (GeoMotes) perform similarly to a traditional wired system in a realistic scenario?

  8. The Influence of Relative Humidity on Dielectric Barrier Discharge Plasma Flow Control Actuator Performance

    NASA Astrophysics Data System (ADS)

    Wicks, M.; Thomas, F. O.; Corke, T. C.; Patel, M.

    2012-11-01

    Dielectric barrier discharge (DBD) plasma actuators possess numerous advantages for flow control applications and have been the focus of several previous studies. Most work has been performed in relatively pristine laboratory settings. In actual flow control applications, however, it is essential to assess the impact of various environmental influences on actuator performance. As a first effort toward assessing a broad range of environmental effects on DBD actuator performance, the influence of relative humidity (RH) is considered. Actuator performance is quantified by force balance measurements of reactive thrust while RH is systematically varied via an ultrasonic humidifier. The DBD plasma actuator assembly, force balance, and ultrasonic humidifier are all contained inside a large, closed test chamber instrumented with RH and temperature sensors in order to accurately estimate the average RH at the actuator. Measurements of DBD actuator thrust as a function of RH for several different applied voltage regimes and dielectric materials and thicknesses are presented. Based on these results, several important design recommendations are made. This work was supported by Innovative Technology Applications Company (ITAC), LLC under a Small Business Innovation Research (SBIR) Phase II Contract No. N00014-11-C-0267 issued by the U.S. Department of the Navy.

  9. Performance Modeling in CUDA Streams - A Means for High-Throughput Data Processing.

    PubMed

    Li, Hao; Yu, Di; Kumar, Anand; Tu, Yi-Cheng

    2014-10-01

    Push-based database management system (DBMS) is a new type of data processing software that streams large volume of data to concurrent query operators. The high data rate of such systems requires large computing power provided by the query engine. In our previous work, we built a push-based DBMS named G-SDMS to harness the unrivaled computational capabilities of modern GPUs. A major design goal of G-SDMS is to support concurrent processing of heterogenous query processing operations and enable resource allocation among such operations. Understanding the performance of operations as a result of resource consumption is thus a premise in the design of G-SDMS. With NVIDIA's CUDA framework as the system implementation platform, we present our recent work on performance modeling of CUDA kernels running concurrently under a runtime mechanism named CUDA stream . Specifically, we explore the connection between performance and resource occupancy of compute-bound kernels and develop a model that can predict the performance of such kernels. Furthermore, we provide an in-depth anatomy of the CUDA stream mechanism and summarize the main kernel scheduling disciplines in it. Our models and derived scheduling disciplines are verified by extensive experiments using synthetic and real-world CUDA kernels.

  10. Cardiorespiratory fitness, cardiovascular workload and risk factors among cleaners; a cluster randomized worksite intervention.

    PubMed

    Korshøj, Mette; Krustrup, Peter; Jørgensen, Marie Birk; Prescott, Eva; Hansen, Åse Marie; Kristiansen, Jesper; Skotte, Jørgen Henrik; Mortensen, Ole Steen; Søgaard, Karen; Holtermann, Andreas

    2012-08-13

    Prevalence of cardiovascular risk factors is unevenly distributed among occupational groups. The working environment, as well as lifestyle and socioeconomic status contribute to the disparity and variation in prevalence of these risk factors. High physical work demands have been shown to increase the risk for cardiovascular disease and mortality, contrary to leisure time physical activity. High physical work demands in combination with a low cardiorespiratory fitness infer a high relative workload and an excessive risk for cardiovascular mortality. Therefore, the aim of this study is to examine whether a worksite aerobic exercise intervention will reduce the relative workload and cardiovascular risk factors by an increased cardiorespiratory fitness. A cluster-randomized controlled trial is performed to evaluate the effect of the worksite aerobic exercise intervention on cardiorespiratory fitness and cardiovascular risk factors among cleaners. Cleaners are eligible if they are employed ≥ 20 hours/week, at one of the enrolled companies. In the randomization, strata are formed according to the manager the participant reports to. The clusters will be balanced on the following criteria: Geographical work location, gender, age and seniority. Cleaners are randomized to either I) a reference group, receiving lectures concerning healthy living, or II) an intervention group, performing worksite aerobic exercise "60 min per week". Data collection will be conducted at baseline, four months and 12 months after baseline, at the worksite during working hours. The data collection will consist of a questionnaire-based interview, physiological testing of health and capacity-related measures, and objective diurnal measures of heart rate, physical activity and blood pressure. Primary outcome is cardiorespiratory fitness. Information is lacking about whether an improved cardiorespiratory fitness will affect the cardiovascular health, and additionally decrease the objectively measured relative workload, in a population with high physical work demands. Previous intervention studies have lacked robust objective measurements of the relative workload and physical work demands. This study will monitor the relative workload and general physical activity before, during after the intervention, and contribute to the understanding of the previously observed opposing effects on cardiovascular health and mortality from occupational and leisure time physical activity. The study is registered as ISRCTN86682076.

  11. Origin matters: diversity affects the performance of alien invasive species but not of native species.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Maron, John L; Schaffner, Urs

    2015-06-01

    At local scales, it has often been found that invasibility decreases with increasing resident plant diversity. However, whether resident community diversity similarly resists invasion by alien versus native species is seldom studied. We examined this issue by invading constructed native plant assemblages that varied in species and functional richness with invasive alien or native Asteraceae species. Assemblages were also invaded with spotted knapweed, Centaurea stoebe, a native European aster that has been previously used in diversity-invasibility experiments in North America. We also conducted a field survey to explore the generality of the patterns generated from our experimental study. Both experimental and observational work revealed that increasing diversity reduced the performance of alien but not native invaders. Centaurea stoebe invading its native community performed poorly regardless of resident diversity, whereas in a parallel, previously published study conducted in North America, C. stoebe easily invaded low-diversity but not high-diversity assemblages. Our results suggest that diversity is an attribute of resident communities that makes them more or less susceptible to invasion by novel invasive alien but not native plant species.

  12. Compromised encoding of proprioceptively determined joint angles in older adults: the role of working memory and attentional load.

    PubMed

    Goble, Daniel J; Mousigian, Marianne A; Brown, Susan H

    2012-01-01

    Perceiving the positions and movements of one's body segments (i.e., proprioception) is critical for movement control. However, this ability declines with older age as has been demonstrated by joint angle matching paradigms in the absence of vision. The aim of the present study was to explore the extent to which reduced working memory and attentional load influence older adult proprioceptive matching performance. Older adults with relatively HIGH versus LOW working memory ability as determined by backward digit span and healthy younger adults, performed memory-based elbow position matching with and without attentional load (i.e., counting by 3 s) during target position encoding. Even without attentional load, older adults with LOW digit spans (i.e., 4 digits or less) had larger matching errors than younger adults. Further, LOW older adults made significantly greater errors when attentional loads were present during proprioceptive target encoding as compared to both younger and older adults with HIGH digit span scores (i.e., 5 digits or greater). These results extend previous position matching results that suggested greater errors in older adults were due to degraded input signals from peripheral mechanoreceptors. Specifically, the present work highlights the role cognitive factors play in the assessment of older adult proprioceptive acuity using memory-based matching paradigms. Older adults with LOW working memory appear prone to compromised proprioceptive encoding, especially when secondary cognitive tasks must be concurrently executed. This may ultimately result in poorer performance on various activities of daily living.

  13. A Simple and Novel Method to Attain Retrograde Ureteral Access after Previous Cohen Cross-Trigonal Ureteral Reimplantation

    PubMed Central

    Adam, Ahmed

    2017-01-01

    Objective To describe a simple, novel method to achieve ureteric access in the Cohen crossed reimplanted ureter, which will allow retrograde working access via the conventional transurethral method. Materials and Methods Under cystoscopic vision, suprapubic needle puncture was performed. The needle was directed (bevel facing) towards the desired ureteric orifice (UO). A guidewire (with a floppy-tip) was then inserted into the suprapubic needle passing into the bladder, and then easily passed into the crossed-reimplanted UO. The distal end of the guidewire was then removed through the urethra with cystoscopic grasping forceps. The straightened ureter then easily facilitated ureteroscopy access, retrograde pyelogram studies, and JJ stent insertion in a conventional transurethral method. Results The UO and ureter were aligned in a more conventional orthotopic course, to allow for conventional transurethral working access. Conclusion A novel method to access the Cohen crossed reimplanted ureter was described. All previously published methods of accessing the crossed ureter were critically appraised. PMID:29463976

  14. Reordering of Nuclear Quantum States in Rare Isotopes

    NASA Astrophysics Data System (ADS)

    Flanagan, Kieran

    2010-02-01

    A key question in modern nuclear physics relates to the ordering of quantum states, and whether the predictions made by the shell model hold true far from stability. Recent innovations in technology and techniques at radioactive beam facilities have allowed access to rare isotopes previously inaccessible to experimentalists. Measurements that have been performed in several regions of the nuclear chart have yielded surprising and dramatic changes in nuclear structure, where level ordering is quite different than expected from previous theoretical descriptions. In order to reconcile the difference between experiment and theory, new shell-model interactions have been proposed, which include the role of the tensor force as part of the monopole term from the expansion of the residual proton-neutron interaction. This has motivated a series of laser spectroscopy experiments that have studied the neutron-rich copper and gallium isotopes at the ISOLDE facility. This work has deduced without nuclear-model dependence the spin, moments and charge radii. The results of this work and their implications for nuclear structure near ^78Ni will be discussed. )

  15. Scalable detection of statistically significant communities and hierarchies, using message passing for modularity

    PubMed Central

    Zhang, Pan; Moore, Cristopher

    2014-01-01

    Modularity is a popular measure of community structure. However, maximizing the modularity can lead to many competing partitions, with almost the same modularity, that are poorly correlated with each other. It can also produce illusory ‘‘communities’’ in random graphs where none exist. We address this problem by using the modularity as a Hamiltonian at finite temperature and using an efficient belief propagation algorithm to obtain the consensus of many partitions with high modularity, rather than looking for a single partition that maximizes it. We show analytically and numerically that the proposed algorithm works all of the way down to the detectability transition in networks generated by the stochastic block model. It also performs well on real-world networks, revealing large communities in some networks where previous work has claimed no communities exist. Finally we show that by applying our algorithm recursively, subdividing communities until no statistically significant subcommunities can be found, we can detect hierarchical structure in real-world networks more efficiently than previous methods. PMID:25489096

  16. Is the recall of verbal-spatial information from working memory affected by symptoms of ADHD?

    PubMed

    Caterino, Linda C; Verdi, Michael P

    2012-10-01

    OJECTIVE: The Kulhavy model for text learning using organized spatial displays proposes that learning will be increased when participants view visual images prior to related text. In contrast to previous studies, this study also included students who exhibited symptoms of ADHD. Participants were presented with either a map-text or text-map condition. The map-text condition led to a significantly higher performance than the text-map condition, overall. However, students who endorsed more symptoms of inattention and hyperactivity-impulsivity scored more poorly when asked to recall text facts, text features, and map features and were less able to correctly place map features on a reconstructed map than were students who endorsed fewer symptoms. The results of the study support the Kulhavy model for typical students; however, the benefit of viewing a display prior to text was not seen for students with ADHD symptoms, thus supporting previous studies that have demonstrated that ADHD appears to negatively affect operations that occur in working memory.

  17. The CIELO collaboration: Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

    DOE PAGES

    Chadwick, M. B.; Capote, R.; Trkov, A.; ...

    2017-01-01

    The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235;8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

  18. The CIELO collaboration: Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

    NASA Astrophysics Data System (ADS)

    Chadwick, M. B.; Capote, R.; Trkov, A.; Kahler, A. C.; Herman, M. W.; Brown, D. A.; Hale, G. M.; Pigni, M.; Dunn, M.; Leal, L.; Plompen, A.; Schillebeeck, P.; Hambsch, F.-J.; Kawano, T.; Talou, P.; Jandel, M.; Mosby, S.; Lestone, J.; Neudecker, D.; Rising, M.; Paris, M.; Nobre, G. P. A.; Arcilla, R.; Kopecky, S.; Giorginis, G.; Cabellos, O.; Hill, I.; Dupont, E.; Danon, Y.; Jing, Q.; Zhigang, G.; Tingjin, L.; Hanlin, L.; Xichao, R.; Haicheng, W.; Sin, M.; Bauge, E.; Romain, P.; Morillon, B.; Noguere, G.; Jacqmin, R.; Bouland, O.; De Saint Jean, C.; Pronyaev, V. G.; Ignatyuk, A.; Yokoyama, K.; Ishikawa, M.; Fukahori, T.; Iwamoto, N.; Iwamoto, O.; Kuneada, S.; Lubitz, C. R.; Palmiotti, G.; Salvatores, M.; Kodeli, I.; Kiedrowski, B.; Roubtsov, D.; Thompson, I.; Quaglioni, S.; Kim, H. I.; Lee, Y. O.; Koning, A. J.; Carlson, A.; Fischer, U.; Sirakov, I.

    2017-09-01

    The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235,8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

  19. Modeling and Simulation of Used Nuclear Fuel During Transportation with Consideration of Hydride Effects and Cyclic Fatigue

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

    Chakraborty, Pritam; Sabharwall, Piyush; Spears, Robert Edward

    2015-09-30

    The objective of this work is to understand the integrity of Used Nuclear Fuel (UNF) during transportation. Previous analysis work has been performed to look at the integrity of UNF during transportation but these analyses have neglected to analyze the effect of hydrides and flaws (fracture mechanics models to capture radial cracking in the cladding). In this study, the clad regions of interest are near the pellet-pellet interfaces. These regions can experience more complex stress-states than the rest of the clad during cooling and have a greater possibility to develop radially reoriented hydrides during vacuum drying.

  20. Discrete Element Modeling (DEM) of Triboelectrically Charged Particles: Revised Experiments

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Calle, Carlos I.; Curry, D. R.; Weitzman, P. S.

    2008-01-01

    In a previous work, the addition of basic screened Coulombic electrostatic forces to an existing commercial discrete element modeling (DEM) software was reported. Triboelectric experiments were performed to charge glass spheres rolling on inclined planes of various materials. Charge generation constants and the Q/m ratios for the test materials were calculated from the experimental data and compared to the simulation output of the DEM software. In this paper, we will discuss new values of the charge generation constants calculated from improved experimental procedures and data. Also, planned work to include dielectrophoretic, Van der Waals forces, and advanced mechanical forces into the software will be discussed.

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