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Sample records for models perform poorly

  1. The Plumbing of Land Surface Models: Is Poor Performance a Result of Methodology or Data Quality?

    Science.gov (United States)

    Haughton, Ned; Abramowitz, Gab; Pitman, Andy J.; Or, Dani; Best, Martin J.; Johnson, Helen R.; Balsamo, Gianpaolo; Boone, Aaron; Cuntz, Matthais; Decharme, Bertrand; hide

    2016-01-01

    The PALS Land sUrface Model Benchmarking Evaluation pRoject (PLUMBER) illustrated the value of prescribing a priori performance targets in model intercomparisons. It showed that the performance of turbulent energy flux predictions from different land surface models, at a broad range of flux tower sites using common evaluation metrics, was on average worse than relatively simple empirical models. For sensible heat fluxes, all land surface models were outperformed by a linear regression against downward shortwave radiation. For latent heat flux, all land surface models were outperformed by a regression against downward shortwave, surface air temperature and relative humidity. These results are explored here in greater detail and possible causes are investigated. We examine whether particular metrics or sites unduly influence the collated results, whether results change according to time-scale aggregation and whether a lack of energy conservation in fluxtower data gives the empirical models an unfair advantage in the intercomparison. We demonstrate that energy conservation in the observational data is not responsible for these results. We also show that the partitioning between sensible and latent heat fluxes in LSMs, rather than the calculation of available energy, is the cause of the original findings. Finally, we present evidence suggesting that the nature of this partitioning problem is likely shared among all contributing LSMs. While we do not find a single candidate explanation forwhy land surface models perform poorly relative to empirical benchmarks in PLUMBER, we do exclude multiple possible explanations and provide guidance on where future research should focus.

  2. Poor Physician Performance in the Netherlands: Characteristics, Causes, and Prevalence.

    Science.gov (United States)

    van den Goor, Myra M P G; Wagner, Cordula C; Lombarts, Kiki M J M H

    2015-07-14

    Poor physician performance has a profound impact on patient safety and society's trust in the health care system. The attention that this topic has received in the media suggests that it is a large-scale issue. However, research about physician performance is still scant; there is little evidence regarding its prevalence. In terminology, characteristics and causes of poor performance seem to be used synonymously. The aim of this study was to describe (i) characteristics of poor performance, (ii) causes contributing to its onset and continuation, and (iii) prevalence of poor performance among physicians in the Netherlands. This is a mixed-methods study involving literature review of 10 electronic databases, review of disciplinary law verdicts, and 12 expert interviews. Each of the 3 methods contributes to the aims of our study. Characteristics of poor performance are predominantly described by deficits in individual physician knowledge, skills, and behavior. Causes of poor performance include aspects such as poor collaboration, lack of criticism, insufficient leadership, and lack of professional development. A prevalence rate of 5% was judged by the experts to be realistic; evidence to underpin this number is lacking. This study discriminates between characteristics and causes of poor performance. Characteristics of poor performance are related to individual physician aspects. Causes contributing to the onset and continuation of poor performance include not only individual components but also work environment and professional development. Our findings therefore underscore the importance of considering poor performance on a system level rather than as a pure individual physician issue.

  3. Poor academic performance among adolescents with epilepsy in ...

    African Journals Online (AJOL)

    In Nigeria, studies have linked epilepsy with missing school, dropping out of school and poor academic performance.4-,11. Factors that predispose a child or adolescent with epilepsy to poor school performance include the age of the child, age of onset of seizures, seizure frequency,12 type of seizure, IQ of the child,4 poor.

  4. Analysis of Poor Performance of Senior Secondary Students in ...

    African Journals Online (AJOL)

    This study investigated the poor performance of students in Chemistry. The widespread poor performance and the negative attitudes towards chemistry of secondary school students have been largely ascribed to teaching problems. A random sample of 109 students from St Pius X College Bodo City was used. The research ...

  5. Factors associated with high school learners' poor performance: a ...

    African Journals Online (AJOL)

    This study, using a non-experimental, exploratory and descriptive method, established learners' and educators' views about factors that contribute to poor performance in mathematics and physical science. Participants were purposefully selected from seven schools with poor pass rates in District 3 of Tshwane North.

  6. Common Characteristics of Good and Poorly Performing PCC Pavements

    Science.gov (United States)

    1998-01-01

    This report documents the analysis and findings of a study to identify the site conditions and design/construction features of concrete pavements (JPCP, JRCP, CRCP) that lead to good performance and those that lead to poor performance. Data from Long...

  7. Poor physician performance in the Netherlands: characteristics, causes, and prevalence.

    NARCIS (Netherlands)

    Goor, M.M.P.G. van den; Wagner, C.; Lombarts, K.M.J.M.H.

    2015-01-01

    Introduction: Poor physician performance has a profound impact on patient safety and society's trust in the health care system. The attention that this topic has received in the media suggests that it is a large-scale issue. However, research about physician performance is still scant; there is

  8. Aggregate packing characteristics of good and poor performing asphalt mixes

    CSIR Research Space (South Africa)

    Denneman, E

    2007-07-01

    Full Text Available The aggregate structure of the compacted mix is a determining factor for the performance of Hot-Mix Asphalt (HMA). In this paper, the grading characteristics of good and poor performing HMA mixes are explored using the concepts of the Bailey method...

  9. Poor flight performance in deep-diving cormorants.

    Science.gov (United States)

    Watanabe, Yuuki Y; Takahashi, Akinori; Sato, Katsufumi; Viviant, Morgane; Bost, Charles-André

    2011-02-01

    Aerial flight and breath-hold diving present conflicting morphological and physiological demands, and hence diving seabirds capable of flight are expected to face evolutionary trade-offs regarding locomotory performances. We tested whether Kerguelen shags Phalacrocorax verrucosus, which are remarkable divers, have poor flight capability using newly developed tags that recorded their flight air speed (the first direct measurement for wild birds) with propeller sensors, flight duration, GPS position and depth during foraging trips. Flight air speed (mean 12.7 m s(-1)) was close to the speed that minimizes power requirement, rather than energy expenditure per distance, when existing aerodynamic models were applied. Flights were short (mean 92 s), with a mean summed duration of only 24 min day(-1). Shags sometimes stayed at the sea surface without diving between flights, even on the way back to the colony, and surface durations increased with the preceding flight durations; these observations suggest that shags rested after flights. Our results indicate that their flight performance is physiologically limited, presumably compromised by their great diving capability (max. depth 94 m, duration 306 s) through their morphological adaptations for diving, including large body mass (enabling a large oxygen store), small flight muscles (to allow for large leg muscles for underwater propulsion) and short wings (to decrease air volume in the feathers and hence buoyancy). The compromise between flight and diving, as well as the local bathymetry, shape the three-dimensional foraging range (<26 km horizontally, <94 m vertically) in this bottom-feeding cormorant.

  10. Analysis of Poor Performance of Senior Secondary Students in ...

    African Journals Online (AJOL)

    First Lady

    2012-10-27

    Oct 27, 2012 ... widespread poor performance and the negative attitudes towards chemistry of secondary school students have ... likert type questionnaire which was administered on 109 secondary school students to obtain ... on the part of students, students not interested in hard work, incompetent teachers in the primary.

  11. Understanding Preclerkship Medical Students’ Poor Performance in Prescription Writing

    OpenAIRE

    James, Henry; Al Khaja, Khalid A. J.; Tayem, Yasin I.; Veeramuthu, Sindhan; Sequeira, Reginald P.

    2016-01-01

    Objectives: This study aimed to explore reasons for poor performance in prescription writing stations of the objective structured practical examination (OSPE) and absenteeism in prescription writing sessions among preclerkship medical students at the Arabian Gulf University (AGU) in Manama, Bahrain. Methods: This descriptive study was carried out between September 2014 and June 2015 among 157 preclerkship medical students at AGU. Data were collected using focus group discussions and a ques...

  12. Residential Electrostatic Precipitator - Performance at efficient and poor combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Baefver, Linda; Yngvesson, Johan; Niklasson, Fredrik

    2012-07-01

    The performance of a pilot residential electrostatic precipitator R{sub E}SP (Applied Plasma Physics AS), was investigated at laboratory. Measurements of TSP (Total Suspended Particles), content of organic and elemental carbon, and mass size distribution of particles upstream and downstream of ESP were performed. Values for PM1 (particles < 1 {mu}m) were calculated from the particle size distributions. Concentrations and size distributions with respect to particle numbers were measured in separate tests. Gas concentrations, temperatures and boiler parameters were also measured. The TSP concentrations upstream of the R{sub E}SP were varied in range of 15-390 mg/m{sub N}{sup 3}. Up to concentrations of about 300 mg/m{sub N}{sup 3}, the TSP-concentrations out from the ESP were less than 20 mg/m{sub N}{sup 3}, which is well below the German emission limit for wood stoves. The removal efficiencies with respect to mass were about 87% at efficient combustion and 93% at poor combustion. Corresponding values with respect to number concentrations were about 97% at efficient combustion and almost 99% at poor combustion. The better performance at poor combustion may be explained by lower flue gas temperature, leading to longer residence time in the ESP. High removal efficiencies were also found with respect to particulate organic and elemental carbon.

  13. Diagnosis of a Poorly Performing Liquid Hydrogen Bulk Storage Sphere

    Science.gov (United States)

    Krenn, Angela G.

    2011-01-01

    There are two 850,000 gallon Liquid Hydrogen (LH2) storage spheres used to support the Space Shuttle Program; one residing at Launch Pad A and the other at Launch Pad B. The LH2 Sphere at Pad B has had a high boiloff rate since being brought into service in the 1960's. The daily commodity loss was estimated to be approximately double that of the Pad A sphere, and well above the minimum required by the sphere's specification. Additionally, after being re-painted in the late 1990's a "cold spot" appeared on the outer sphere which resulted in a poor paint bond, and mold formation. Thermography was used to characterize the area, and the boiloff rate was continually evaluated. All evidence suggested that the high boiloff rate was caused by an excessive heat leak into the inner sphere due to an insulation void in the annulus. Pad B was recently taken out of Space Shuttle program service which provided a unique opportunity to diagnose the sphere's poor performance. The sphere was drained and inerted, and then opened from the annular relief device on the top where a series of boroscoping operations were accomplished. Boroscoping revealed a large Perlite insulation void in the region of the sphere where the cold spot was apparent. Perlite was then trucked in and off-loaded into the annular void region until the annulus was full. The sphere has not yet been brought back into service.

  14. Finance for the Poor: An Assessment of the Performance of ...

    African Journals Online (AJOL)

    The introduction of microfinance in the Nigerian financial system is an attempt to provide the poor with access to micro-financial services. Micro-banks that are supposed to provide these services are faced with many challenges. Among these are: inability to reach a greater number of the poor; funding of commercial sectors ...

  15. Becoming a caregiver: attachment theory and poorly performing doctors.

    Science.gov (United States)

    Adshead, Gwen

    2010-02-01

    In this paper, I review a theoretical paradigm (attachment theory) which facilitates an understanding of how human care-giving and care-eliciting behaviours develop and are maintained over the lifespan. I argue that this paradigm has particular utility in: (i) the training of doctors; (ii) understanding why some doctors and medical students experience high levels of stress, and (iii) developing interventions to help those who struggle to manage high levels of work-related stress. I carried out a review of key texts and previously published studies of attachment styles in caregivers. Large-scale epidemiological studies, using valid and reliable measures, show that insecure attachment styles are found in a proportion of normal populations of both males and females. Insecure attachment is associated with impaired stress management and subtle deficits in care-giving sensitivity. It is reasonable to assume that a proportion of students entering medical training and doctors with performance problems may have insecure attachment styles which influence how they approach their training experience and how they manage occupational stress. Attachment theory is a useful paradigm for thinking about training as a professional caregiver. Insecure early attachment experiences may be a risk factor for poor stress management in some medical students and doctors who are exposed to increasing demands as carers. These findings lead to suggestions for possible research and support interventions.

  16. Analytical review based on statistics on good and poor financial performance of LPD in Bangli regency.

    Science.gov (United States)

    Yasa, I. B. A.; Parnata, I. K.; Susilawati, N. L. N. A. S.

    2018-01-01

    This study aims to apply analytical review model to analyze the influence of GCG, accounting conservatism, financial distress models and company size on good and poor financial performance of LPD in Bangli Regency. Ordinal regression analysis is used to perform analytical review, so that obtained the influence and relationship between variables to be considered further audit. Respondents in this study were LPDs in Bangli Regency, which amounted to 159 LPDs of that number 100 LPDs were determined as randomly selected samples. The test results found GCG and company size have a significant effect on both the good and poor financial performance, while the conservatism and financial distress model has no significant effect. The influence of the four variables on the overall financial performance of 58.8%, while the remaining 41.2% influenced by other variables. Size, FDM and accounting conservatism are variables, which are further recommended to be audited.

  17. Analysis of Poor Performance of Senior Secondary Students in ...

    African Journals Online (AJOL)

    First Lady

    2012-10-27

    Oct 27, 2012 ... in chemistry on the part of students, overpopulation, poor background in chemistry, chemistry difficulty, the abstract nature of chemistry, lack of and outdated instructional materials, expensive chemistry text books, lack of encouragement from parents, other engagements in the home and uneducated.

  18. Poor academic performance among adolescents with epilepsy in ...

    African Journals Online (AJOL)

    Background. Adolescents with epilepsy experience significant academic difficulties. However, little is known about the effects of epilepsy on the academic performance of adolescents with the disorder in Northern Nigeria. Objective. To assess the academic performance of adolescents with epilepsy and factors associated ...

  19. Poor School Performance: Contributing Factors and Consequences, with Emphasis on the Nonwhite Child.

    Science.gov (United States)

    Gwinn, Diane G.

    Research on poor school performance--with emphasis on the nonwhite child--is discussed in terms of differences children bring to school, the school process, and consequences of poor school performance. Individual factors related to poor achievement are noted to include membership in a disadvantaged minority group, broken homes and absent fathers,…

  20. Poor sleep quality impairs cognitive performance in older adults.

    Science.gov (United States)

    Miyata, Seiko; Noda, Akiko; Iwamoto, Kunihiro; Kawano, Naoko; Okuda, Masato; Ozaki, Norio

    2013-10-01

    The prevalence of insomnia increases with age. Short sleep duration is associated with deficits in cognitive performance. We hypothesized that short sleep duration and sleep quality influence cognitive performance in older adults. The study included 78 adults aged 60 years and over (72.2 ± 5.9 years). Total sleep time and sleep efficiency (total sleep time/time in bed × 100) were calculated using actigraphy. We evaluated cognitive performance with the continuous performance test-identical pairs and the number-back test. Sleep apnea was evaluated overnight with a portable home monitoring system. The accuracy of the 0-back test significantly decreased in participants with total sleep time less than 5 h compared with those with total sleep time greater than 7 h, but there was no significant difference in continuous performance test-identical pairs between the two groups. Participants with sleep efficiency sleep efficiency ≥85%. There were no significant differences in the accuracy of number-back tests and continuous performance test-identical pairs between apnea-hypopnea index ≥15 h(-1) and apnea-hypopnea index sleep time and sleep efficiency were significantly correlated with accuracy on the 0-back test. Age and sleep efficiency were significantly correlated with accuracy on the 1-back test. Multiple regression analysis revealed that total sleep time was independently correlated with accuracy on the 0-back test, while age was independently correlated with accuracy on the 1-back test. Our findings suggest that sleep duration and sleep quality may play a role in cognitive performance in older adults. © 2013 European Sleep Research Society.

  1. Warning signals for poor performance improve human-robot interaction

    NARCIS (Netherlands)

    Brule, R. van den; Bijlstra, G.; Dotsch, R.; Haselager, W.F.G.; Wigboldus, D.H.J.

    2016-01-01

    The present research was aimed at investigating whether human-robot interaction (HRI) can be improved by a robot's nonverbal warning signals. Ideally, when a robot signals that it cannot guarantee good performance, people could take preventive actions to ensure the successful completion of the

  2. Warning Signals for Poor Performance Improve Human-Robot Interaction

    NARCIS (Netherlands)

    van den Brule, Rik; Bijlstra, Gijsbert; Dotsch, Ron; Haselager, Pim; Wigboldus, Daniel HJ

    2016-01-01

    The present research was aimed at investigating whether human-robot interaction (HRI) can be improved by a robot’s nonverbal warning signals. Ideally, when a robot signals that it cannot guarantee good performance, people could take preventive actions to ensure the successful completion of the

  3. Early Teacher Expectations Disproportionately Affect Poor Children's High School Performance

    Science.gov (United States)

    Sorhagen, Nicole S.

    2013-01-01

    This research used prospective longitudinal data to examine the associations between first-grade teachers' over- and underestimation of their students' math abilities, basic reading abilities, and language skills and the students' high school academic performance, with special attention to the subject area and moderating effects of student…

  4. Overcoming challenges of catastrophe modelling in data poor regions

    Science.gov (United States)

    Grassby, L.; Millinship, I.; Breinl, K.

    2012-04-01

    There is an increasing demand for loss accumulation tools in expanding international insurance markets such as India, China and Thailand. This reflects the combination of an increase in exposures in these territories as industry intensifies and urban development expands, as well as several notable natural catastrophes affecting these areas over the past few years (e.g. extreme floods in Mumbai in 2006 and in Thailand in 2011). Large, global insurers and reinsurers are embracing the opportunity to underwrite these exposures but only where adequate tools are available to provide understanding of the hazards, exposures and potential losses. Unlike more developed countries, data availability in these regions is typically limited and of poor resolution, but model development is still required in order to analyse the risk. Some of the modelling challenges associated with data limitations include: (1) dealing with a lack of hydrological data which results in greater uncertainty of the flow rate and event frequency; (2) lower DTM resolution than that available across much of Europe, which underlies the hazard component of the catastrophe model; (3) limited accessibility to data that characterises the Built Environment including information on different building types and their susceptibility to damage; and (4) a lack of claims data from previous events or engineering research into the vulnerability of different building types. This is used to generate of country and structure specific vulnerability curves that explain the relationship between hazard intensity and damages. By presenting an industry specific flood model for data-poor India in collaboration with Allianz Re, we illustrate how we have overcome many of these challenges to allow loss accumulations to be made. The resulting model was successfully validated against the floods in Mumbai and Surat in 2006 and is being developed further with the availability of new data.

  5. Quality of Sleep and Performance in the Navy: A Longitudinal Study of Good and Poor Sleepers

    Science.gov (United States)

    1982-05-21

    identify by block number) Humans Insomnia Sleep quality Sleep EEC Performance Good and poor sleepers 20. ABSTRACT (Continue on reverse side if...8217 subjective sleep habits and POMS scores were very similar to our good and poor sleepers defined by subjective estimates of sleep quality. This...differences in our follow-up samples. Since over 60% of our poor sleepers do not meet EEG criteria for sleep -onset insomnia , a reasonable question is

  6. Association of tic disorders with poor academic performance in central Spain: a population-based study.

    Science.gov (United States)

    Cubo, Esther; Trejo, José; Ausín, Vanesa; Sáez, Sara; Delgado, Vanesa; Macarrón, Jesus; Cordero, José; Louis, Elan D; Kompoliti, Katie; Benito-León, Julián

    2013-07-01

    To analyze the association between tic disorders and poor academic performance in school-aged children. This was a cross-sectional, observational study conducted in a randomly selected sample of mainstream school-aged children (aged 6-16 years). The sampling frame included different types of schools and educational levels. Children with poor academic performance (eg, repeating a grade, special needs), and tic disorders (defined based on Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria) were identified. Children with and without tics and children with and without poor academic performance were compared in terms of clinical features (ie, medical history and neurologic and psychiatric comorbidities), school, and environmental characteristics. Logistic regression analyses were performed using school performance (dependent variable) and tic disorders (independent variable), after adjusting for confounding variables. The study cohort comprised 1867 children (mean age, 10.9 + 2.9 years; 1007 males [53.9%]). Tics were present in 162 children (8.6%), and poor academic performance was noted in 223 (11.9%). Overall poor academic performance was associated with age (OR, 1.71; P disorder (OR, 1.38; P tic disorders (OR, 0.29; P = .01). After adjusting for other covariates, the presence of tic disorders was not associated with poor academic performance in our cohort. Early academic support and modification of environmental characteristics are needed for children at higher risk for school dysfunction, to enhance academic performance. Copyright © 2013 Mosby, Inc. All rights reserved.

  7. Performance improvement for GPS single frequency kinematic relative positioning under poor satellite visibility.

    Science.gov (United States)

    Chen, Wantong

    2016-01-01

    Reliable ambiguity resolution in difficult environments such as during setting/rising events of satellites or during limited satellite visibility is a significant challenge for GPS single frequency kinematic relative positioning. Here, a recursive estimation method combining both code and carrier phase measurements was developed that can tolerate recurrent satellite setting/rising and accelerate initialization in motion. We propose an ambiguity dimension expansion method by utilizing the partial ambiguity relevance of previous and current observations. In essence, this method attempts to integrate all useful information into the recursive estimation equation and performs a better least squares adjustment. Using this method, the success rate of the extended ambiguity estimation is independent of the satellite setting and shows robust performance despite poor satellite visibility. Our model allows integration of other useful information into the recursive process. Actual experiments in urban environments demonstrate that the proposed algorithm can improve the reliability and availability of relative positioning.

  8. Relationship between Poor Sleep and Daytime Cognitive Performance in Young Adults with Autism

    Science.gov (United States)

    Limoges, Elyse; Bolduc, Christianne; Berthiaume, Claude; Mottron, Laurent; Godbout, Roger

    2013-01-01

    Poor sleep is a common feature in autism even though patients themselves do not necessarily complain. The impact of poor sleep on daytime cognitive functioning in autism is not well-known and we therefore investigated whether sleep in autism correlates with daytime cognitive performance. A battery of non-verbal tasks was administered, in the…

  9. Factors Associated with High School Learners' Poor Performance: A Spotlight on Mathematics and Physical Science

    Science.gov (United States)

    Makgato, Moses; Mji, Andile

    2006-01-01

    This study, using a non-experimental, exploratory and descriptive method, established learners' and educators' views about factors that contribute to poor performance in mathematics and physical science. Participants were purposefully selected from seven schools with poor pass rates in District 3 of Tshwane North. Focused group interviews with ten…

  10. [Excessive Daytime Sleepiness, Poor Quality Sleep, and Low Academic Performance in Medical Students].

    Science.gov (United States)

    Machado-Duque, Manuel Enrique; Echeverri Chabur, Jorge Enrique; Machado-Alba, Jorge Enrique

    2015-01-01

    Quality of sleep and excessive daytime sleepiness (EDS) affect cognitive ability and performance of medical students. This study attempts to determine the prevalence of EDS, sleep quality, and assess their association with poor academic performance in this population. A descriptive, observational study was conducted on a random sample of 217 medical students from the Universidad Tecnológica de Pereira, who completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the Epworth sleepiness scale. Sociodemographic, clinic and academic variables were also measured. Multivariate analyses for poor academic performance were performed. The included students had a mean age of 21.7±3.3 years, of whom 59.4% were men. Almost half (49.8%) had EDS criteria, and 79.3% were poor sleepers (PSQI ≥ 5), while 43.3% had poor academic performance during the last semester. The bivariate analysis showed that having used tobacco or alcohol until intoxicated, fairly bad subjective sleep quality, sleep efficiency performance. Sleep efficiency academic performance (P=.024; OR = 4.23; 95% CI, 1.12-15.42) in the multivariate analysis. A poor sleep quality determined by low efficiency was related to poor academic achievement at the end of semester in medical students. Copyright © 2015 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  11. Early detection of poor adherers to statins: applying individualized surveillance to pay for performance.

    Directory of Open Access Journals (Sweden)

    Andrew J Zimolzak

    Full Text Available Medication nonadherence costs $300 billion annually in the US. Medicare Advantage plans have a financial incentive to increase medication adherence among members because the Centers for Medicare and Medicaid Services (CMS now awards substantive bonus payments to such plans, based in part on population adherence to chronic medications. We sought to build an individualized surveillance model that detects early which beneficiaries will fall below the CMS adherence threshold.This was a retrospective study of over 210,000 beneficiaries initiating statins, in a database of private insurance claims, from 2008-2011. A logistic regression model was constructed to use statin adherence from initiation to day 90 to predict beneficiaries who would not meet the CMS measure of proportion of days covered 0.8 or above, from day 91 to 365. The model controlled for 15 additional characteristics. In a sensitivity analysis, we varied the number of days of adherence data used for prediction.Lower adherence in the first 90 days was the strongest predictor of one-year nonadherence, with an odds ratio of 25.0 (95% confidence interval 23.7-26.5 for poor adherence at one year. The model had an area under the receiver operating characteristic curve of 0.80. Sensitivity analysis revealed that predictions of comparable accuracy could be made only 40 days after statin initiation. When members with 30-day supplies for their first statin fill had predictions made at 40 days, and members with 90-day supplies for their first fill had predictions made at 100 days, poor adherence could be predicted with 86% positive predictive value.To preserve their Medicare Star ratings, plan managers should identify or develop effective programs to improve adherence. An individualized surveillance approach can be used to target members who would most benefit, recognizing the tradeoff between improved model performance over time and the advantage of earlier detection.

  12. Poor Executive Functions among Children with Moderate-into-Severe Asthma: Evidence from WCST Performance.

    Science.gov (United States)

    Taha, Haitham

    2017-01-01

    Executive functions (EFs) measures of 27 asthmatic children, with general learning difficulties, were tested by using the Wisconsin card sorting test (WCST), and were compared to the performances of 30 non-asthmatic children with general learning difficulties. The results revealed that the asthmatic group has poor performance through all the WCST psychometric parameters and especially the perseverative errors one. The results were discussed in light of the postulation that poor EFs could be associated with the learning difficulties of asthmatic children. Neurophysiological framework has been suggested to explain the etiology of poor EFs among children with moderate into severe asthma.

  13. Poor performance in physical education - a risk factor for bully victimization. A case-control study.

    Science.gov (United States)

    Bejerot, Susanne; Edgar, Johan; Humble, Mats B

    2011-03-01

    Poor social skills are a risk factor for becoming bullied, which could explain why this frequently occurs to children with autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Poor social skills tend to coexist with clumsiness. According to a pilot study, poor performance in physical education (PE) was correlated with bully victimization. Sixty-nine healthy university students reported performance in PE and bully victimization in childhood. In addition, the participants responded to questionnaires for ADHD and ASDs to assess personality traits related to increased risk for bully victimization. Below average performance in PE was a risk factor of being bullied in school with an odds ratio of 3.6 [95% confidence interval: 1.23-10.5; p = 0.017]. Strong correlations between poor performance in PE and long duration of victimization (p = 0.007) and poor performance in PE and high frequency of victimization (p = 0.008) were found. Autistic traits were related to performance below average in PE. Poor motor skills are a strong risk factor for becoming bullied. Prevention programmes that identify, protect and empower the clumsy children could be an important step to avoid bullying of the most vulnerable children. © 2010 The Author(s)/Acta Paediatrica © 2010 Foundation Acta Paediatrica.

  14. Doctors' stress responses and poor communication performance in simulated bad-news consultations.

    Science.gov (United States)

    Brown, Rhonda; Dunn, Stewart; Byrnes, Karen; Morris, Richard; Heinrich, Paul; Shaw, Joanne

    2009-11-01

    No studies have previously evaluated factors associated with high stress levels and poor communication performance in breaking bad news (BBN) consultations. This study determined factors that were most strongly related to doctors' stress responses and poor communication performance during a simulated BBN task. In 2007, the authors recruited 24 doctors comprising 12 novices (i.e., interns/residents with 1-3 years' experience) and 12 experts (i.e., registrars, medical/radiation oncologists, or cancer surgeons, with more than 4 years' experience). Doctors participated in simulated BBN consultations and a number of control tasks. Five-minute-epoch heart rate (HR), HR variability, and communication performance were assessed in all participants. Subjects also completed a short questionnaire asking about their prior experience BBN, perceived stress, psychological distress (i.e., anxiety, depression), fatigue, and burnout. High stress responses were related to inexperience with BBN, fatigue, and giving bad versus good news. Poor communication performance in the consultation was related to high burnout and fatigue scores. These results suggest that BBN was a stressful experience for doctors even in a simulated encounter, especially for those who were inexperienced and/or fatigued. Poor communication performance was related to burnout and fatigue, but not inexperience with BBN. These results likely indicate that burnout and fatigue contributed to stress and poor work performance in some doctors during the simulated BBN task.

  15. Self-Reported Sleep Quality Predicts Poor Cognitive Performance in Healthy Older Adults

    OpenAIRE

    Robert D. Nebes; Daniel J. Buysse; Edythe M. Halligan; Patricia R. Houck; Timothy H. Monk

    2009-01-01

    This study examined the relation between sleep quality and cognitive performance in older adults, controlling for common medical comorbidities. Participants were community volunteers who, while not selected on the basis of their sleep, did report substantial variability in sleep quality. Good and poor sleepers differed on tests of working memory, attentional set shifting, and abstract problem solving but not on processing speed, inhibitory function, or episodic memory. Poor sleep was also ass...

  16. Perception of Overweight Is Associated with Poor Academic Performance in US Adolescents

    Science.gov (United States)

    Florin, Todd A.; Shults, Justine; Stettler, Nicolas

    2011-01-01

    Background: To improve understanding of the mechanisms affecting the relationship between adolescent obesity and poor academic performance, we examined the association of overweight or perceived weight status with academic achievement. Methods: We performed a cross-sectional study of 14-17-year-olds (N = 11,012) from the nationally representative…

  17. Poor Gait Performance and Prediction of Dementia: Results From a Meta-Analysis.

    Science.gov (United States)

    Beauchet, Olivier; Annweiler, Cédric; Callisaya, Michele L; De Cock, Anne-Marie; Helbostad, Jorunn L; Kressig, Reto W; Srikanth, Velandai; Steinmetz, Jean-Paul; Blumen, Helena M; Verghese, Joe; Allali, Gilles

    2016-06-01

    Poor gait performance predicts risk of developing dementia. No structured critical evaluation has been conducted to study this association yet. The aim of this meta-analysis was to systematically examine the association of poor gait performance with incidence of dementia. An English and French Medline search was conducted in June 2015, with no limit of date, using the medical subject headings terms "Gait" OR "Gait Disorders, Neurologic" OR "Gait Apraxia" OR "Gait Ataxia" AND "Dementia" OR "Frontotemporal Dementia" OR "Dementia, Multi-Infarct" OR "Dementia, Vascular" OR "Alzheimer Disease" OR "Lewy Body Disease" OR "Frontotemporal Dementia With Motor Neuron Disease" (Supplementary Concept). Poor gait performance was defined by standardized tests of walking, and dementia was diagnosed according to international consensus criteria. Four etiologies of dementia were identified: any dementia, Alzheimer disease (AD), vascular dementia (VaD), and non-AD (ie, pooling VaD, mixed dementias, and other dementias). Fixed effects meta-analyses were performed on the estimates in order to generate summary values. Of the 796 identified abstracts, 12 (1.5%) were included in this systematic review and meta-analysis. Poor gait performance predicted dementia [pooled hazard ratio (HR) combined with relative risk and odds ratio = 1.53 with P analysis provides evidence that poor gait performance predicts dementia. This association depends on the type of dementia; poor gait performance is a stronger predictor of non-AD dementias than AD. Copyright © 2016 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

  18. Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers.

    Science.gov (United States)

    Shetty, Hemanth Narayan; Puttabasappa, Manjula

    Hearing aids are prescribed to alleviate loss of audibility. It has been reported that about 31% of hearing aid users reject their own hearing aid because of annoyance towards background noise. The reason for dissatisfaction can be located anywhere from the hearing aid microphone till the integrity of neurons along the auditory pathway. To measure spectra from the output of hearing aid at the ear canal level and frequency following response recorded at the auditory brainstem from individuals with hearing impairment. A total of sixty participants having moderate sensorineural hearing impairment with age range from 15 to 65 years were involved. Each participant was classified as either Good or Poor Hearing aid Performers based on acceptable noise level measure. Stimuli /da/ and /si/ were presented through loudspeaker at 65dB SPL. At the ear canal, the spectra were measured in the unaided and aided conditions. At auditory brainstem, frequency following response were recorded to the same stimuli from the participants. Spectrum measured in each condition at ear canal was same in good hearing aid performers and poor hearing aid performers. At brainstem level, better F 0 encoding; F 0 and F 1 energies were significantly higher in good hearing aid performers than in poor hearing aid performers. Though the hearing aid spectra were almost same between good hearing aid performers and poor hearing aid performers, subtle physiological variations exist at the auditory brainstem. The result of the present study suggests that neural encoding of speech sound at the brainstem level might be mediated distinctly in good hearing aid performers from that of poor hearing aid performers. Thus, it can be inferred that subtle physiological changes are evident at the auditory brainstem in a person who is willing to accept noise from those who are not willing to accept noise. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier

  19. Poor academic performance: A perspective of final year diagnostic radiography students

    International Nuclear Information System (INIS)

    Gqweta, Ntokozo

    2012-01-01

    Introduction: A study was conducted on final year diagnostic radiography students at a University of Technology in Durban. The aim of the study was to investigate the final year diagnostic radiography students' opinions and views on academic performance in order to inform teaching and learning methods. The objectives were: •To explore the students' opinions regarding poor performance. •To identify strategies to improve academic performance. Method: A qualitative, interpretive approach was used to explain and understand the students' lived experiences of their academic performances. A short open ended questionnaire was administered to a cohort of final diagnostic radiography students following feedback on a written assessment. Questionnaire responses were then manually captured and analyzed. Results: Five (5) themes were identified that could possibly be associated with poor academic performance. These themes were, poor preparation, lack of independent study, difficulty in understanding learning content and misinterpretation of assessment questions, inefficient studying techniques as well as perceived improvement strategies. Conclusion: Students identified their inadequate preparation and the lack of dedicated independent studying as the main reasons for poor performance. Students preferred to be taught in an assessment oriented manner. However their identified improvement strategies were aligned with the learner centred approach.

  20. Relationship between poor sleep and daytime cognitive performance in young adults with autism.

    Science.gov (United States)

    Limoges, Élyse; Bolduc, Christianne; Berthiaume, Claude; Mottron, Laurent; Godbout, Roger

    2013-04-01

    Poor sleep is a common feature in autism even though patients themselves do not necessarily complain. The impact of poor sleep on daytime cognitive functioning in autism is not well-known and we therefore investigated whether sleep in autism correlates with daytime cognitive performance. A battery of non-verbal tasks was administered, in the morning after a second night of sleep in the laboratory, to 17 young adults with autism and normal intelligence, and 14 typically developed individuals matched for age and IQ; none of the participants complained about sleep problems. Two dimensions of attention (sustained and selective) and 4 types of memory (working, declarative, sensory-motor and cognitive procedural) were tested. Individuals with autism showed clear signs of poor sleep. Their performance differed from the controls in response speed but not in accuracy. Signs of poor sleep in the autism group were significantly correlated with either normal performance (selective attention and declarative memory) or performance inferior to that of the controls (sensory-motor and cognitive procedural memories). Both groups presented a significant negative correlation between slow-wave sleep (SWS) and learning a sensory-motor procedural memory task. Only control participants showed a positive association between SWS duration and number of figures recalled on the declarative memory task. Correlation patterns differed between groups when sleep spindles were considered: they were negatively associated with number of trials needed to learn the sensory-motor procedural memory task in autism and with reaction time and number of errors on selective attention in the controls. Correlation between rapid eye movements (REMs) in REM sleep and cognitive procedural memory was not significant. We conclude that some signs reflecting the presence of poor sleep in adults with high-functioning autism correlate with various aspects of motor output on non-verbal performance tasks. The question is

  1. Poor understanding of marketing principles has led to poor marketing management performance: Consideration of four marketing myths.

    OpenAIRE

    Pickton, David W.; Wright, Sheila

    2000-01-01

    Marketing is accused of poor management practice. This paper argues that this is grounded in a confusion of marketing thinking and marketing action which results from widely held beliefs and myths that surround the marketing management process, making it difficult for marketing to develop as a coherent management discipline and profession. Barriers to its successful implementation are created at both strategic and tactical levels. The paper presents an exploration of four myths which are oft...

  2. Experiences of Second-Class Citizenship Related to Continued Poor Academic Performance of Minority Xhosa Learners

    Science.gov (United States)

    Dreyer, Lorna M.; Singh, Suzanne A. M.

    2016-01-01

    This article examines the subjective life experiences of racial minority Xhosa speakers and the factors that contribute to their continued poor academic performance in a previously Whites-only school in South Africa. Vygotskian sociocultural perspective in relation to creating a democratic educational system and Bronfenbrenner's biosystemic theory…

  3. Effect of Wii-intervention on balance of children with poor motor performance

    NARCIS (Netherlands)

    Dorothee Jelsma; Esther Hartman; dr. Remo Mombarg

    2013-01-01

    The purpose of this study was to investigate the effects of training with the Wii-balance board on balance and balance-related skills of children with poor motor performance. Twenty-nine children (23 boys, 6 girls; aged 7–12 years) participated in this study and were randomly assigned to an

  4. Effect of Wii-intervention on balance of children with poor motor performance

    NARCIS (Netherlands)

    Mombarg, Remo; Jelsma, Dorothee; Hartman, Esther

    The purpose of this study was to investigate the effects of training with the Wii-balance board on balance and balance-related skills of children with poor motor performance. Twenty-nine children (23 boys, 6 girls; aged 7-12 years) participated in this study and were randomly assigned to an

  5. Poorly Performing Physicians: Does the Script Concordance Test Detect Bad Clinical Reasoning?

    Science.gov (United States)

    Goulet, Francois; Jacques, Andre; Gagnon, Robert; Charlin, Bernard; Shabah, Abdo

    2010-01-01

    Introduction: Evaluation of poorly performing physicians is a worldwide concern for licensing bodies. The College des Medecins du Quebec currently assesses the clinical competence of physicians previously identified with potential clinical competence difficulties through a day-long procedure called the Structured Oral Interview (SOI). Two peer…

  6. The Influence of Closing Poor Performing Primary Schools on the Educational Attainment of Students

    Science.gov (United States)

    De Witte, Kristof; Van Klaveren, Chris

    2014-01-01

    This paper examines whether the closure of poor performing primary schools improved students' educational attainment. It is believed that school closure affects children's educational outcomes positively because children switch to better primary schools. At the same time, school closure creates a social disturbance such that educational outcomes…

  7. Frequency of and risk factors for poor cognitive performance in hemodialysis patients

    Science.gov (United States)

    There are few detailed data on cognition in patients undergoing dialysis. We evaluated the frequency of and risk factors for poor cognitive performance using detailed neurocognitive testing. In this cross-sectional cohort study, 314 hemodialysis patients from 6 Boston-area hemodialysis units underwe...

  8. Eliminating Poor Performers: The Catalyst to Improve Quality in the U.S. Army

    Science.gov (United States)

    2012-05-01

    Eliminating Poor Performers : The catalyst to improve quality in the U.S. Army 5a. CONTRACT NUMBER N/A 5b. GRANT NUMBER N/A 5c. PROGRAM...ELEMENT NUMBER N/A 6. AUTHOR(S) MAJOR Clifton T. Causey, USA 5d. PROJECT NUMBER N/A 5e. TASK NUMBER N/A 5f. WORK UNIT NUMBER N/A 7. PERFORMING ... PERFORMING ORGANIZATION REPORT NUMBER N/A 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) N/A 10. SPONSOR/MONITOR’S ACRONYM(S) N/A 11

  9. 198Au grain implantation for early tongue cancer in patients of advanced age or poor performance status

    International Nuclear Information System (INIS)

    Ryu, Yoshiharu; Shibuya, Hitoshi; Hayashi, Keiji

    2013-01-01

    Brachytherapy using 198 Au grains is minimally invasive and the only curative treatment for early tongue cancer in patients of advanced age or poor performance status available in our institution. From March 1993 to February 2008, 198 Au grains were used to treat a group of 96 Stage I–II tongue cancer patients who could not undergo surgery or brachytherapy using 192 Ir pins because of an advanced age (≥75 years) or poor performance status (≥2). The patients were followed for 3.9 ± 3.3 years, and the cause-specific survival and local control rates were determined. Survival analyses were performed using the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazard model. The results were compared with those for a group of 193 early tongue-cancer patients who underwent treatment using iridium pins. The 5-year cause-specific survival and local control rates of the 198 Au grains group were 71% and 68%, respectively, both of which were 16% lower than the corresponding rates for the 192 Ir pins group. Our study demonstrated that as the last curative treatment available, 198 Au grain implantation could be used to achieve moderate treatment results for early tongue cancer in patients of advanced age or poor performance status

  10. Does self-reported sleep quality predict poor cognitive performance among elderly living in elderly homes?

    Science.gov (United States)

    Amer, Motassem S; Hamza, Sarah A; El Akkad, Rania M; Abdel Galeel, Yamen I I

    2013-01-01

    Sleep complaints are common among elderly, especially institutionalized elderly, as they experience poorer sleep quality and higher use of sedative hypnotics, when compared to community-dwelling elderly. Recent findings suggest that there may be a relationship between poor quality of sleep and cognitive deficits. This study aimed at studying the relation between sleep quality and cognitive performance in older adults living in elderly homes. 100 elderly living in an elderly home in El Mansoura, Egypt, were recruited in this study, 50 cases with subjective poor quality of sleep and 50 controls with subjective good quality of sleep as assessed by Pittsburgh sleep quality index (PSQI). Each participant went through comprehensive geriatric assessment (CGA), including geriatric depression scale (GDS), assessment of cognitive function by mini mental state examination (MMSE). 52% of poor sleepers showed impaired MMSE, while only 24% of good sleepers had impaired MMSE. Both orientation and (attention and calculation) were more affected (P = 0.027 and 0.035, respectively). Linear correlation coefficient between PSQI and different variables revealed significant negative correlation with total MMSE score, attention and calculation. Poor quality of sleep is related to cognitive impairment among elderly living in elderly homes and this problem should be taken in consideration among this group of elders.

  11. Distinct Aging Effects on Functional Networks in Good and Poor Cognitive Performers.

    Science.gov (United States)

    Lee, Annie; Tan, Mingzhen; Qiu, Anqi

    2016-01-01

    Brain network hubs are susceptible to normal aging processes and disruptions of their functional connectivity are detrimental to decline in cognitive functions in older adults. However, it remains unclear how the functional connectivity of network hubs cope with cognitive heterogeneity in an aging population. This study utilized cognitive and resting-state functional magnetic resonance imaging data, cluster analysis, and graph network analysis to examine age-related alterations in the network hubs' functional connectivity of good and poor cognitive performers. Our results revealed that poor cognitive performers showed age-dependent disruptions in the functional connectivity of the right insula and posterior cingulate cortex (PCC), while good cognitive performers showed age-related disruptions in the functional connectivity of the left insula and PCC. Additionally, the left PCC had age-related declines in the functional connectivity with the left medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC). Most interestingly, good cognitive performers showed age-related declines in the functional connectivity of the left insula and PCC with their right homotopic structures. These results may provide insights of neuronal correlates for understanding individual differences in aging. In particular, our study suggests prominent protection roles of the left insula and PCC and bilateral ACC in good performers.

  12. Well performance model

    International Nuclear Information System (INIS)

    Thomas, L.K.; Evans, C.E.; Pierson, R.G.; Scott, S.L.

    1992-01-01

    This paper describes the development and application of a comprehensive oil or gas well performance model. The model contains six distinct sections: stimulation design, tubing and/or casing flow, reservoir and near-wellbore calculations, production forecasting, wellbore heat transmission, and economics. These calculations may be performed separately or in an integrated fashion with data and results shared among the different sections. The model analysis allows evaluation of all aspects of well completion design, including the effects on future production and overall well economics

  13. Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

    Science.gov (United States)

    Stancliffe, Richard J.; Kennedy, Catherine R.; Lau, Herbert H. B.; Beers, Timothy C.

    2013-10-01

    Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently, Kinman et al. discovered that the highly carbon- and barium-enriched metal-poor star SDSS J1707+58 is in fact an RR Lyrae pulsator. This gives us an object in a definite evolutionary state where the effects of dilution of material during the main sequence are minimized owing to the object having passed through first dredge-up. We perform detailed stellar modelling of putative progenitor systems in which we accreted material from asymptotic giant branch stars in the mass range 1-2 M⊙. We investigate how the surface abundances are affected by the inclusion of mechanisms like thermohaline mixing and gravitational settling. While we are able to find a reasonable fit to the carbon and sodium abundances of SDSS J1707+58, suggesting accretion of around 0.1 M⊙ from a 2 M⊙ companion, the strontium and barium abundances remain problematic and this object may have experienced something other than a standard s-process. We have more success in fitting the abundances of the mildly carbon-enriched, metal-poor RR Lyrae pulsator TY Gru (CS 22881-071), which we suggest received 0.1 M⊙ of material from a companion of around 1 M⊙.

  14. NIF capsule performance modeling

    Directory of Open Access Journals (Sweden)

    Weber S.

    2013-11-01

    Full Text Available Post-shot modeling of NIF capsule implosions was performed in order to validate our physical and numerical models. Cryogenic layered target implosions and experiments with surrogate targets produce an abundance of capsule performance data including implosion velocity, remaining ablator mass, times of peak x-ray and neutron emission, core image size, core symmetry, neutron yield, and x-ray spectra. We have attempted to match the integrated data set with capsule-only simulations by adjusting the drive and other physics parameters within expected uncertainties. The simulations include interface roughness, time-dependent symmetry, and a model of mix. We were able to match many of the measured performance parameters for a selection of shots.

  15. The Stock Performance of C. Everett Koop Award Winners Compared With the Standard & Poor's 500 Index

    Science.gov (United States)

    Goetzel, Ron Z.; Fabius, Raymond; Fabius, Dan; Roemer, Enid C.; Thornton, Nicole; Kelly, Rebecca K.; Pelletier, Kenneth R.

    2016-01-01

    Objective: To explore the link between companies investing in the health and well-being programs of their employees and stock market performance. Methods: Stock performance of C. Everett Koop National Health Award winners (n = 26) was measured over time and compared with the average performance of companies comprising the Standard and Poor's (S&P) 500 Index. Results: The Koop Award portfolio outperformed the S&P 500 Index. In the 14-year period tracked (2000–2014), Koop Award winners’ stock values appreciated by 325% compared with the market average appreciation of 105%. Conclusions: This study supports prior and ongoing research demonstrating a higher market valuation—an affirmation of business success by Wall Street investors—of socially responsible companies that invest in the health and well-being of their workers when compared with other publicly traded firms. PMID:26716843

  16. Human performance breakdowns are rarely accidents: they are usually very poor choices with disastrous results

    International Nuclear Information System (INIS)

    Besco, Robert O.

    2004-01-01

    When human error is involved in the error chain of accidents in complex systems, the causes of the errors are very seldom the result of: - a random slip,; - one inadvertent oversight,; - a single unintended action,; - one mis-perceived event,; - simple mal-performance of a complex action, or; - a poor training program for the human operators. Invariably, the cause of the break down is in a very poor conscious choice by someone from the operator back through system designer, the supervision, management and leadership through the entire organization. Usually the operator bears the burden of the blame and is either rebuked, retrained or replaced. In systems such as commercial aviation, complex manufacturing systems, power plants, process control systems, information-processing systems and communications networks, the replacement or retraining of individuals or even classes of individuals usually does not result in any long-term improvement of the safety or effectiveness of the system. What is needed is a system that identifies the reasons why the operators made the errors. Further a system is needed that can recommend what can be done to improve the future performance within the system. The professional performance analysis system (PPAS) has been developed and applied to more than 50 major aircraft accidents in the past 30 years. The PPAS is a direct outgrowth of the human performance analysis system developed by Robert Mager over 45 years ago. The PPAS system is applied after a complete and unbiased definition and description of the events of the accident or incident has been developed by the teams of accident investigation and accident reconstruction professionals. The PPAS then uses a systematic protocol and algorithm to determine the reasons as to why the humans committed the errors or why they performed at subnormal performance levels. This process is based on quantitative behavioral science principles and findings that have been demonstrated valid for many

  17. Poor precompetitive sleep habits, nutrients' deficiencies, inappropriate body composition and athletic performance in elite gymnasts.

    Science.gov (United States)

    Silva, M-R G; Paiva, T

    2016-09-01

    This study aimed to evaluate body composition, sleep, precompetitive anxiety and dietary intake on the elite female gymnasts' performance prior to an international competition. Sixty-seven rhythmic gymnasts of high performance level were evaluated in relation to sport and training practice, body composition, sleep duration, daytime sleepiness by the Epworth Sleepiness Scale (ESS), sleep quality by the Pittsburgh Sleep Quality Index (PSQI), precompetitive anxiety by the Sport Competition Anxiety Test form A (SCAT-A) and detailed dietary intake just before an international competition. Most gymnasts (67.2%) suffered from mild daytime sleepiness, 77.6% presented poor sleep quality and 19.4% presented high levels of precompetitive anxiety. The majority of gymnasts reported low energy availability (EA) and low intakes of important vitamins including folate, vitamins D, E and K; and minerals, including calcium, iron, boron and magnesium (p performance was positively correlated with age (p = .001), sport practice (p = .024), number of daily training hours (p = .000), number of hours of training/week (p = .000), waist circumference (WC) (p = .008) and sleep duration (p = .005). However, it was negatively correlated with WC/hip circumference (p = .000), ESS (p = .000), PSQI (p = .042), SCAT-A (p = .002), protein g/kg (p = .028), EA (p = .002) and exercise energy expenditure (p = .000). High performance gymnasts presented poor sleep habits with consequences upon daytime sleepiness, sleep quality and low energy availability.

  18. Violence exposure, sleep disturbance, and poor academic performance in middle school.

    Science.gov (United States)

    Lepore, Stephen J; Kliewer, Wendy

    2013-11-01

    Violence has been linked to poor academic outcomes in youth, but there is little understanding of the mechanisms underlying this relation. This longitudinal survey study investigated whether sleep disturbance potentially mediates the associations between academic achievement and two forms of violence exposure--community violence and peer victimization-- in 498 seventh-grade youth. Structural equation models showed that community violence was associated with lower grade point average (GPA) directly and indirectly via sleep problems, whereas peer victimization was associated with lower GPA just indirectly via sleep problems. The structural models controlled for potential confounds, including depressive symptoms, intrusive thoughts and absenteeism. The findings suggest that failing grades and sleepiness in school may be signs that youth are exposed to violence. Interventions to improve sleep hygiene and reduce violence exposure may help to improve academic outcomes for youth.

  19. Population pharmacokinetic modeling of glibenclamide in poorly controlled South African type 2 diabetic subjects

    Directory of Open Access Journals (Sweden)

    Rambiritch V

    2016-07-01

    Full Text Available Virendra Rambiritch,1 Poobalan Naidoo,2 Breminand Maharaj,1 Goonaseelan Pillai3 1University of KwaZulu-Natal, Durban, 2Department of Internal Medicine, RK Khan Regional Hospital, Chatsworth, South Africa; 3Novartis Pharma AG, Basel, Switzerland Aim: The aim of this study was to describe the pharmacokinetics (PK of glibenclamide in poorly controlled South African type 2 diabetic subjects using noncompartmental and model-based methods. Methods: A total of 24 subjects with type 2 diabetes were administered increasing doses (0 mg/d, 2.5 mg/d, 5 mg/d, 10 mg/d, and 20 mg/d of glibenclamide daily at 2-week intervals. Plasma glibenclamide, glucose, and insulin determinations were performed. Blood sampling times were 0 minute, 30 minutes, 60 minutes, 90 minutes, and 120 minutes (post breakfast sampling and 240 minutes, 270 minutes, 300 minutes, 330 minutes, 360 minutes, and 420 minutes (post lunch sampling on days 14, 28, 42, 56, and 70 for doses of 0 mg, 2.5 mg, 5.0 mg, 10 mg, and 20 mg, respectively. Blood sampling was performed after the steady state was reached.  A total of 24 individuals in the data set contributed to a total of 841 observation records. The PK was analyzed using noncompartmental analysis methods, which were implemented in WinNonLin®, and population PK analysis using NONMEM®. Glibenclamide concentration data were log transformed prior to fitting. Results: A two-compartmental disposition model was selected after evaluating one-, two-, and three-compartmental models to describe the time course of glibenclamide plasma concentration data. The one-compartment model adequately described the data; however, the two-compartment model provided a better fit. The three-compartment model failed to achieve successful convergence. A more complex model, to account for enterohepatic recirculation that was observed in the data, was unsuccessful. Conclusion: In South African diabetic subjects, glibenclamide demonstrates linear PK and was best

  20. Mau desempenho escolar: uma visão atual Poor school performance: an updated review

    Directory of Open Access Journals (Sweden)

    Cláudia Machado Siqueira

    2011-02-01

    Full Text Available Este estudo tem como objetivo uma revisão atualizada sobre o tema de mau desempenho escolar para profissionais da área de saúde e educação. Aborda aspectos atuais da educação, de aprendizagem e das principais condições envolvidas em mau desempenho escolar. Apresenta dados atualizados sobre os principais aspectos da neurobiologia, epidemiologia, etiologia, quadro clínico, comorbidades, diagnóstico, intervenção precoce e tratamento das principais patologias envolvidas. Trata-se de uma revisão abrangente, não sistemática da literatura sobre aprendizagem, desempenho escolar, transtorno de aprendizagem (dislexia, discalculia e disgrafia, transtorno de déficit de atenção/hiperatividade (TDA/H e transtorno de desenvolvimento de coordenação (TDC. O mau desempenho escolar é um sintoma frequente em nossas crianças com graves repercussões emocionais, sociais e econômicas. Uma visão atualizada do tema facilita o raciocínio clínico, o diagnóstico correto e o tratamento adequado.This study aims to develop a comprehensive review on the issue of poor school performance for professionals in both health and education areas. It discusses current aspects of education, learning and the main conditions involved in underachievement. It also presents updated data on key aspects of neurobiology, epidemiology, etiology, clinical presentation, comorbidities and diagnosis, early intervention and treatment of the major pathologies comprised. It is a comprehensive, non-systematic literature review on learning, school performance, learning disorders (dyslexia, dyscalculia and dysgraphia, attention deficit / hyperactivity disorder (ADHD and developmental coordination disorder (DCD. Poor school performance is a frequent problem faced by our children, causing serious emotional, social and economic issues. An updated view of the subject facilitates clinical reasoning, accurate diagnosis and appropriate treatment.

  1. Effect of Wii-intervention on balance of children with poor motor performance.

    Science.gov (United States)

    Mombarg, Remo; Jelsma, Dorothee; Hartman, Esther

    2013-09-01

    The purpose of this study was to investigate the effects of training with the Wii-balance board on balance and balance-related skills of children with poor motor performance. Twenty-nine children (23 boys, 6 girls; aged 7-12 years) participated in this study and were randomly assigned to an experimental and control group. All children scored below the 16th percentile on a standardized test of motor ability and balance skills (Movement Assessment Battery for children (M-ABC-2)). Before and after a six-week Wii-intervention (M=8h, 22 min, SD=53 min), the balance skills of the experimental group and control group were measured with the M-ABC-2 and the Bruininks-Oseretsky test of motor proficiency (BOT-2). Both groups improved on all tests. The M-ABC-2 and the BOT-2 total balance-scores of the experimental group improved significantly from pre to post intervention, whereas those of the control group showed no significant progress. This resulted in significant interaction-effects, favoring the experimental children. No transfer-effects of the intervention on balance-related skills were demonstrated. Our findings showed that the Wii-balance board is an effective intervention for children with poor balance control. Further development and investigation of the intervention could be directed toward the implementation of the newly acquired balance-skills in daily life. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Relationship between weekend catch-up sleep and poor performance on attention tasks in Korean adolescents.

    Science.gov (United States)

    Kim, Seog Ju; Lee, Yu Jin; Cho, Seong-Jin; Cho, In-Hee; Lim, Weonjeong; Lim, Wonshin

    2011-09-01

    To investigate the relationship between insufficient sleep and poor attention in Korean adolescents, adjusting for potential confounding factors of depressed mood and habitual snoring. School-based cross-sectional study. Eight high schools in 3 cities in the Republic of Korea. A sample of 2638 urban high school students (42.2% male and 57.8% female; mean [SD] age, 17.3 [0.6] years [age range, 14-19 years]) completed questionnaires and computerized attention tasks during the school term. Weekend catch-up sleep. Self-reported sleep schedules and habits, including sleep duration, bedtime, wake-up time, depressed mood, and habitual snoring. Also measured were numbers of omission and commission errors on computerized attention tasks. The mean (SD) sleep duration on weekdays was 5 hours 42 minutes (1 hour 0 minutes) per day and on weekends was 8 hours 24 minutes (1 hour 36 minutes) per day. The mean (SD) weekend catch-up sleep was 2 hours 42 minutes (1 hour 42 minutes) per day. After adjusting for age, sex, depressed mood (Beck Depression Inventory score, ≥10), habitual snoring, and weekday sleep duration, increased weekend catch-up sleep was significantly associated with more omission and commission errors on sustained attention tasks (P sleep as an indicator of insufficient weekday sleep is associated with poor performance on objective attention tasks. Assessment of catch-up sleep and sleep duration may be useful for physicians to evaluate sleep insufficiency and its adverse effects on attention in adolescents.

  3. Medial olivocochlear function in children with poor speech-in-noise performance and language disorder.

    Science.gov (United States)

    Rocha-Muniz, Caroline Nunes; Mamede Carvallo, Renata Mota; Schochat, Eliane

    2017-05-01

    Contralateral masking of transient-evoked otoacoustic emissions is a phenomenon that suggests an inhibitory effect of the olivocochlear efferent auditory pathway. Many studies have been inconclusive in demonstrating a clear connection between this system and a behavioral speech-in-noise listening skill. The purpose of this study was to investigate the activation of a medial olivocochlear (MOC) efferent in children with poor speech-in-noise (PSIN) performance and children with language impairment and PSIN (SLI + PSIN). Transient evoked otoacoustic emissions (TEOAEs) with and without contralateral white noise were tested in 52 children (between 6 and 12 years). These children were arranged in three groups: typical development (TD) (n = 25), PSIN (n = 14) and SLI + PSI (n = 13). PSIN and SLI + PSI groups presented reduced otoacoustic emission suppression in comparison with the TD group. Our finding suggests differences in MOC function among children with typical development and children with poor SIN and language problems. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Malaria is associated with poor school performance in an endemic area of the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Lacerda Marcus VG

    2009-10-01

    Full Text Available Abstract Background Approximately 40% of the world's population is at risk for malaria. In highly endemic tropical areas, malaria is a major cause of morbidity and mortality during infancy. There is a complex interrelationship between malaria, malnutrition and intestinal helminths, and this may impair cognitive development in children. The aim of this study was to determine the relationship between malaria and school performance in children living in an endemic area where Plasmodium vivax is the species responsible for most of the cases. Methods The study was conducted in the Municipality of Careiro, Amazonas, Brazil, with five to14 year-old children, studying the first eight grades of public school, during the year 2008. After an initial active case detection, during nine months of follow-up, passive malaria cases detection was instituted, through a thick blood smear performed in every child with fever. School performance was evaluated by the final notes in Mathematics and Portuguese Language. Performance was considered poor when either of the final notes in these disciplines was below the 50th percentile for the respective class and grade. Results The total number of students followed-up in the cohort was 198. Malarial attacks were reported in 70 (35.4% of these students, with no cases of severe disease. Plasmodium vivax was detected in 69.2% of the attacks, Plasmodium falciparum in 25.5% and both species in 5.3%. In the multivariate analysis, adjusting for age, mother's education, time living in the study area and school absenteeism, presenting with at least one episode of malaria independently predicted a poor performance at school [OR = 1.91 (1.04-3.54; p = 0.039]. Conclusion Non-severe malaria compromises the school performance of children even during a nine-month follow-up, potentially contributing to the maintenance of underdevelopment in countries endemic for malaria. This is the first evidence of such impact in Latin America, where P

  5. Poor oral health including active caries in 187 UK professional male football players: clinical dental examination performed by dentists.

    Science.gov (United States)

    Needleman, Ian; Ashley, Paul; Meehan, Lyndon; Petrie, Aviva; Weiler, Richard; McNally, Steve; Ayer, Chris; Hanna, Rob; Hunt, Ian; Kell, Steven; Ridgewell, Paul; Taylor, Russell

    2016-01-01

    The few studies that have assessed oral health in professional/elite football suggest poor oral health with minimal data on impact on performance. The aim of this research was to determine oral health in a representative sample of professional footballers in the UK and investigate possible determinants of oral health and self-reported impact on well-being, training and performance. Clinical oral health examination of senior squad players using standard methods and outcomes carried out at club training facilities. Questionnaire data were also collected. 8 teams were included, 5 Premier League, 2 Championship and 1 League One. 6 dentists examined 187 players who represented >90% of each senior squad. Oral health was poor: 37% players had active dental caries, 53% dental erosion and 5% moderate-severe irreversible periodontal disease. 45% were bothered by their oral health, 20% reported an impact on their quality of life and 7% on training or performance. Despite attendance for dental check-ups, oral health deteriorated with age. This is the first large, representative sample study in professional football. Oral health of professional footballers is poor, and this impacts on well-being and performance. Successful strategies to promote oral health within professional football are urgently needed, and research should investigate models based on best evidence for behaviour change and implementation science. Furthermore, this study provides strong evidence to support oral health screening within professional football. 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/

  6. Development and testing of watershed-scale models for poorly drained soils

    Science.gov (United States)

    Glenn P. Fernandez; George M. Chescheir; R. Wayne Skaggs; Devendra M. Amatya

    2005-01-01

    Watershed-scale hydrology and water quality models were used to evaluate the crrmulative impacts of land use and management practices on dowrzstream hydrology and nitrogen loading of poorly drained watersheds. Field-scale hydrology and nutrient dyyrutmics are predicted by DRAINMOD in both models. In the first model (DRAINMOD-DUFLOW), field-scale predictions are coupled...

  7. Uncovering phenotypes of poor-pitch singing: the Sung Performance Battery (SPB).

    Science.gov (United States)

    Berkowska, Magdalena; Dalla Bella, Simone

    2013-01-01

    Singing is as natural as speaking for humans. Increasing evidence shows that the layman can carry a tune (e.g., when asked to sing a well-known song or to imitate single pitches, intervals and short melodies). Yet, important individual differences exist in the general population with regard to singing proficiency. Some individuals are particularly inaccurate or imprecise in producing or imitating pitch information (poor-pitch singers), thus showing a variety of singing phenotypes. Unfortunately, so far there is not a standard set of tasks for assessing singing proficiency in the general population, allowing to uncover and characterize individual profiles of poor-pitch singing. Different tasks and analysis methods are typically used in various experiments, making the comparison of the results across studies arduous. To fill this gap we propose here a new tool for assessing singing proficiency (the Sung Performance Battery, SPB). The SPB starts from the assessment of participants' vocal range followed by five tasks: (1) single-pitch matching, (2) pitch-interval matching, (3) novel-melody matching, (4) singing from memory of familiar melodies (with lyrics and on a syllable), and (5) singing of familiar melodies (with lyrics and on a syllable) at a slow tempo indicated by a metronome. Data analysis via acoustical methods provides objective measures of pitch accuracy and precision in terms of absolute and relative pitch. The SPB has been tested in a group of 50 occasional singers. The results indicate that the battery is useful for characterizing proficient singing and for detecting cases of inaccurate and/or imprecise singing.

  8. Uncovering phenotypes of poor-pitch singing: The Sung Performance Battery (SPB

    Directory of Open Access Journals (Sweden)

    Magdalena eBerkowska

    2013-10-01

    Full Text Available Singing is as natural as speaking for humans. Increasing evidence shows that the layman can carry a tune (e.g., when asked to sing a well-known song or to imitate single pitches, intervals and short melodies. Yet, important individual differences exist in the general population with regard to singing proficiency. Some individuals are particularly inaccurate or imprecise in producing or imitating pitch information (poor-pitch singers, thus showing a variety of singing phenotypes. Unfortunately, so far there is not a standard set of tasks for assessing singing proficiency in the general population, allowing to uncover and characterize individual profiles of poor-pitch singing. Different tasks and analysis methods are typically used in various experiments, making the comparison of the results across studies arduous. To fill this gap we propose here a new tool for assessing singing proficiency (the Sung Performance Battery, SPB. The SPB starts from the assessment of participants’ vocal range followed by five tasks: 1 single-pitch matching, 2 pitch-interval matching, 3 novel-melody matching, 4 singing from memory of familiar melodies (with lyrics and on a syllable, and 5 singing of familiar melodies (with lyrics and on a syllable at a slow tempo indicated by a metronome. Data analysis via acoustical methods provides objective measures of pitch accuracy and precision in terms of absolute and relative pitch. The SPB has been tested in a group of 50 occasional singers. The results indicate that the battery is useful for characterizing proficient singing and for detecting cases of inaccurate and/or imprecise singing.

  9. Adeno-associated viral vector serotype 5 poorly transduces liver in rat models.

    Directory of Open Access Journals (Sweden)

    Paula S Montenegro-Miranda

    Full Text Available Preclinical studies in mice and non-human primates showed that AAV serotype 5 provides efficient liver transduction and as such seems a promising vector for liver directed gene therapy. An advantage of AAV5 compared to serotype 8 already shown to provide efficient correction in a phase 1 trial in patients suffering from hemophilia B, is its lower seroprevalence in the general population. Our goal is liver directed gene therapy for Crigler-Najjar syndrome type I, inherited severe unconjugated hyperbilirubinemia caused by UGT1A1 deficiency. In a relevant animal model, the Gunn rat, we compared the efficacy of AAV 5 and 8 to that of AAV1 previously shown to be effective. Ferrying a construct driving hepatocyte specific expression of UGT1A1, both AAV8 and AAV1 provided an efficient correction of hyperbilirubinemia. In contrast to these two and to other animal models AAV5 failed to provide any correction. To clarify whether this unexpected finding was due to the rat model used or due to a problem with AAV5, the efficacy of this serotype was compared in a mouse and two additional rat strains. Administration of an AAV5 vector expressing luciferase under the control of a liver specific promoter confirmed that this serotype poorly performed in rat liver, rendering it not suitable for proof of concept studies in this species.

  10. Extracurricular Activity as Factor Forming Interest in Educationally-Cognitive Activity in Students with Poor Academic Performance

    Directory of Open Access Journals (Sweden)

    V I Kazarenkov

    2013-12-01

    Full Text Available In the article the problem of forming an interest in learning in students through the extracurricular activity is considered; the importance of the extracurricular activity as a factor of the development of the interest in educationally-cognitive activity in the college students with poor academic performance is revealed; the conditions providing the efficiency of using the extracurricular activity for the stimulation of the interest in learning in students with poor academic performance are accentuated.

  11. How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep ( Ovis canadensis ) Herd.

    Science.gov (United States)

    Wood, Mary E; Fox, Karen A; Jennings-Gaines, Jessica; Killion, Halcyon J; Amundson, Sierra; Miller, Michael W; Edwards, William H

    2017-01-01

    We evaluated bighorn sheep ( Ovis canadensis ) ewes and their lambs in captivity to examine the sources and roles of respiratory pathogens causing lamb mortality in a poorly performing herd. After seven consecutive years of observed December recruitments of sheep from the remnant Gribbles Park herd in Colorado, US were captured and transported to the Thorne-Williams Wildlife Research Center in Wyoming in March 2013. Ewes were sampled repeatedly over 16 mo. In April 2014, ewes were separated into individual pens prior to lambing. Upon death, lambs were necropsied and tested for respiratory pathogens. Six lambs developed clinical respiratory disease and one lamb was abandoned. Pathology from an additional six lambs born in 2013 was also evaluated. Mycoplasma ovipneumoniae , leukotoxigenic Mannheimia spp., leukotoxigenic Bibersteinia trehalosi , and Pasteurella multocida all contributed to lamb pneumonia. Histopathology suggested a continuum of disease, with lesions typical of pasteurellosis predominating in younger lambs and lesions typical of mycoplasmosis predominating in older lambs. Mixed pathology was observed in lambs dying between these timeframes. We suspected that all the ewes in our study were persistently infected and chronically shedding the bacteria that contributed to summer lamb mortality.

  12. Performance comparison of sand and fine sawdust vermifilters in treating concentrated grey water for urban poor.

    Science.gov (United States)

    Adugna, Amare T; Andrianisa, Harinaivo A; Konate, Yacouba; Ndiaye, Awa; Maiga, Amadou H

    2015-01-01

    A comparative investigation was conducted for 10 months with sand and fine sawdust vermifilters and a control unit to treat concentrated grey water generated from a poor urban household in Ouagadougou, Burkina Faso. Each of the filters was made up of cylindrical DN200-PVC pipes and filled with 10 cm of gravel at the bottom. On top of the gravel layer, filter 1 (fully sand, F1) was completed with 40 cm of sand and 10 cm of fine sawdust, filter 2 (partially sand, F2) with 20 cm of sand and 30 cm of fine sawdust, respectively, and filter 3 (fully sawdust, F3) and 4 (control, F4) with 50 cm of fine sawdust only. Two hundred Eudrilus eugeniae earthworms were inoculated in each of the vermifilters. The vermifiltration system was supplied with grey water four times per day at a hydraulic loading rate of 64 L/m(2)/day on a batch basis. The removal efficiencies of biological oxygen demand, total chemical oxygen demand, and dissolved chemical oxygen demand (dCOD) by the vermifilters were 25-30% higher than the control, but little differences were observed in terms of total suspended solids and coliform removal efficiencies. Though there was no significant difference in the performance of the three vermifilters (p > 0.05), except for dCOD removal efficiency, the lifespan of F2 and F3 was longer than that of F1. Therefore, fine sawdust can substitute sand as a filter medium in vermifilters.

  13. In vitro models to evaluate the permeability of poorly soluble drug entities: Challenges and perspectives

    DEFF Research Database (Denmark)

    Buckley, S. T.; Fischer, S. M.; Fricker, G.

    2012-01-01

    The application of in vitro models in drug permeability studies represents a useful screening tool for assessing the biopharmaceutical appropriateness of new chemical entities (NCEs). Of note, there remains an ever-increasing number of NCEs which exhibit poor aqueous solubility. However, in their......The application of in vitro models in drug permeability studies represents a useful screening tool for assessing the biopharmaceutical appropriateness of new chemical entities (NCEs). Of note, there remains an ever-increasing number of NCEs which exhibit poor aqueous solubility. However......, in their classical configuration, both cellular and non-cellular in vitro models show numerous deficiencies in their ability to accurately model the absorption of such compounds. As a consequence, investigators continue to explore the possibility of modifying different experimental parameters in an attempt to yield...... a more bio-relevant model system which offers good compatibility with poorly soluble compounds. Moreover, in many instances poorly soluble drugs necessitate the inclusion of excipients to facilitate efficient delivery and to enhance their bioavailability. Thus, there exists an increasing demand...

  14. Modelling of spatially complex human-ecosystem, rural-urban and rich-poor interactions

    CSIR Research Space (South Africa)

    Naude, AH

    2008-06-01

    Full Text Available The paper outlines the challenges of modelling and assessing spatially complex human-ecosystem interactions, and the need to simultaneously consider rural-urban and rich-poor interactions. The context for exploring these challenges is South Africa...

  15. MATHEMATICAL MODEL OF POWER CONSUMPTION FOR SOME OIL PIPE-LINE SECTIONS WITH POOR OPERATIONAL STABILITY

    Directory of Open Access Journals (Sweden)

    J. N. Kolesnik

    2005-01-01

    Full Text Available Mathematical model of power consumption for technologically completed and non-completed oil pipe-line sections with poor operational stability has been developed on the basis of daily indices concerning oil transportation regimes. The model permits to take into account tendencies in power consumption under various time prediction cycles and ranges of oil freight turnover, changes in the bulk and characteristics of the transported oil, configuration and design parameters of oil pipe-line.

  16. How do high and low levels of social trust affect the long-run performance of poor economies?

    DEFF Research Database (Denmark)

    Gundlach, Erich; Svendsen, Gert Tinggaard

    2018-01-01

    Poor countries with high levels of social trust are shown to experience a hump-shaped pattern of long-run growth. With social trust modeled as a human capital externality, a calibrated two-sector model (Lucas 2009) replicates the observed hump-shaped growth path. The simulation results imply...

  17. Unexpected poor performance of presumed high-quality power line filter, and how it improved

    NARCIS (Netherlands)

    Moonen, Dominicus Johannes Guilielmus; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2015-01-01

    A 20 A, 440 V three p hase power line filter for a radar transmitter, designed using the best components available and following the correct rules for filter design, showed unexpected poor common mode attenuation levels at frequencies above, already, a few megahertz. Component self-parasitic, as

  18. Explanatory models of diabetes in urban poor communities in Accra, Ghana.

    Science.gov (United States)

    de-Graft Aikins, Ama; Awuah, Raphael Baffour; Pera, Tuula Anneli; Mendez, Montserrat; Ogedegbe, Gbenga

    2015-01-01

    The objective of the study was to examine explanatory models of diabetes and diabetes complications among urban poor Ghanaians living with diabetes and implications for developing secondary prevention strategies. Twenty adults with type 2 diabetes were recruited from three poor communities in Accra. Qualitative data were obtained using interviews that run between 40 and 90 minutes. The interviews were audio-taped, transcribed and analysed thematically, informed by the 'explanatory model of disease' concept. Respondents associated diabetes and its complications with diet, family history, lifestyle factors (smoking, excessive alcohol consumption and physical inactivity), psychological stress and supernatural factors (witchcraft and sorcery). These associations were informed by biomedical and cultural models of diabetes and disease. Subjective experience, through a process of 'body-listening,' constituted a third model on which respondents drew to theorise diabetes complications. Poverty was an important mediator of poor self-care practices, including treatment non-adherence. The biomedical model of diabetes was a major source of legitimate information for self-care practices. However, this was understood and applied through a complex framework of cultural theories of chronic disease, the biopsychological impact of everyday illness experience and the disempowering effects of poverty. An integrated biopsychosocial approach is proposed for diabetes intervention in this research community.

  19. A Western Dietary Pattern Is Associated with Poor Academic Performance in Australian Adolescents

    Directory of Open Access Journals (Sweden)

    Anett Nyaradi

    2015-04-01

    Full Text Available The aim of this study was to investigate cross-sectional associations between dietary patterns and academic performance among 14-year-old adolescents. Study participants were from the Western Australian Pregnancy Cohort (Raine Study. A food frequency questionnaire was administered when the adolescents were 14 years old, and from the dietary data, a ‘Healthy’ and a ‘Western’ dietary pattern were identified by factor analysis. The Western Australian Literacy and Numeracy Assessment (WALNA results from grade nine (age 14 were linked to the Raine Study data by The Western Australian Data Linkage Branch. Associations between the dietary patterns and the WALNA (mathematics, reading and writing scores were assessed using multivariate linear regression models adjusting for family and socioeconomic characteristics. Complete data on dietary patterns, academic performance and covariates were available for individuals across the different analyses as follows: n = 779 for mathematics, n = 741 for reading and n = 470 for writing. Following adjustment, significant negative associations between the ‘Western’ dietary pattern and test scores for mathematics (β = −13.14; 95% CI: −24.57; −1.76; p = 0.024 and reading (β = −19.16; 95% CI: −29.85; −8.47; p ≤ 0.001 were observed. A similar trend was found with respect to writing (β = −17.28; 95% CI: −35.74; 1.18; p = 0.066. ANOVA showed significant trends in estimated means of academic scores across quartiles for both the Western and Healthy patterns. Higher scores for the ‘Western’ dietary pattern are associated with poorer academic performance in adolescence.

  20. Athletes Rated as Poor Single-Leg Squat Performers Display Measureable Differences in Single-Leg Squat Biomechanics Compared to Good Performers.

    Science.gov (United States)

    Garrick, Lachlan E; Alexander, Bryce C; Schache, Anthony G; Pandy, Marcus G; Crossley, Kay M; Collins, Natalie J

    2017-11-15

    It is important to validate single-leg squat visual rating criteria used in clinical practice and research. Foot orthoses may improve single-leg squat performance in those who demonstrate biomechanics associated with increased risk of lower-limb injury. Validate visual rating criteria proposed by Crossley et al, by determining whether athletes rated as poor single-leg squat performers display different single-leg squat biomechanics than good performers; and evaluate immediate effects of foot orthoses on single-leg squat biomechanics in poor performers. Comparative cross-sectional study. University laboratory. 79 asymptomatic athletes underwent video classification of single-leg squat performance based on established visual rating criteria (overall impression, trunk posture, pelvis 'in space', hip movement, knee movement), and were rated as good (n=23), fair (n=41) or poor (n=15) performers. A subset of good (n=16) and poor (n=12) performers underwent biomechanical assessment, completing five continuous single-leg squats on their dominant limb while three-dimensional motion analysis and ground reaction force data were recorded. Poor performers repeated the task standing on prefabricated foot orthoses. Peak external knee adduction moment (KAM) and peak angles for the trunk, hip, knee and ankle. Compared to good performers, poor performers had a significantly lower peak KAM (mean difference 0.11 Nm/kg, 95% confidence interval [CI] 0.02 to 0.2 Nm/kg), higher peak hip adduction angle (-4.3°, -7.6° to -0.9°), and higher peak trunk axial rotation towards their stance limb (3.8°, 0.4° to 7.2°). Foot orthoses significantly increased the peak KAM in poor performers (-0.06 Nm/kg, -0.1 to -0.01 Nm/kg), with values approximating those observed in good performers. Findings validate Crossley et al's visual rating criteria for single-leg squat performance in asymptomatic athletes, and suggest that 'off-the-shelf' foot orthoses may be a simple intervention for poor performers

  1. Principles of Sonar Performance Modeling

    NARCIS (Netherlands)

    Ainslie, M.A.

    2010-01-01

    Sonar performance modelling (SPM) is concerned with the prediction of quantitative measures of sonar performance, such as probability of detection. It is a multidisciplinary subject, requiring knowledge and expertise in the disparate fields of underwater acoustics, acoustical oceanography, sonar

  2. Assessing Ecosystem Model Performance in Semiarid Systems

    Science.gov (United States)

    Thomas, A.; Dietze, M.; Scott, R. L.; Biederman, J. A.

    2017-12-01

    In ecosystem process modelling, comparing outputs to benchmark datasets observed in the field is an important way to validate models, allowing the modelling community to track model performance over time and compare models at specific sites. Multi-model comparison projects as well as models themselves have largely been focused on temperate forests and similar biomes. Semiarid regions, on the other hand, are underrepresented in land surface and ecosystem modelling efforts, and yet will be disproportionately impacted by disturbances such as climate change due to their sensitivity to changes in the water balance. Benchmarking models at semiarid sites is an important step in assessing and improving models' suitability for predicting the impact of disturbance on semiarid ecosystems. In this study, several ecosystem models were compared at a semiarid grassland in southwestern Arizona using PEcAn, or the Predictive Ecosystem Analyzer, an open-source eco-informatics toolbox ideal for creating the repeatable model workflows necessary for benchmarking. Models included SIPNET, DALEC, JULES, ED2, GDAY, LPJ-GUESS, MAESPA, CLM, CABLE, and FATES. Comparison between model output and benchmarks such as net ecosystem exchange (NEE) tended to produce high root mean square error and low correlation coefficients, reflecting poor simulation of seasonality and the tendency for models to create much higher carbon sources than observed. These results indicate that ecosystem models do not currently adequately represent semiarid ecosystem processes.

  3. The association of snoring and risk of obstructive sleep apnea with poor academic performance among university students.

    Science.gov (United States)

    Khassawneh, Basheer Y; Alkhatib, Loiy L; Ibnian, Ali M; Khader, Yousef S

    2018-04-20

    Subjects with obstructive sleep apnea (OSA) have neurocognitive dysfunction. The aim of this study was to estimate the prevalence of symptoms and risk of OSA among university students and the association with academic performance. A cross-sectional study was conducted at Jordan University of Science and Technology. Students from faculties of engineering, medicine, nursing, pharmacy, and dentistry were asked to participate in this study. The Berlin Sleep Questionnaire was used to report symptoms and risk of OSA. Below average cumulative scores were considered poor academic performance. A total of 777 students (51% female; mean age, 20 years) completed the study questionnaire. According to the study definition, 42 students (5.4%) had high risk for OSA. Snoring was reported by 11% and daytime sleepiness and fatigue by 30%. Compared to female students, male students had more snoring (14.6 vs. 7.6%, p = 0.002) and higher risk for OSA (6.5 vs. 1.6%, p = 0.001). Both self-reported snoring and being at high risk for OSA were associated with poor academic performance (27.9 vs. 11.6% and 23.1 vs. 9.2%, respectively; p academic performance in students at high risk for OSA was 2.4 (CI 1.11-5.2, p = 0.027). Snoring and OSA were uncommon among university students. However, both were more common among male students and were associated with poor academic performance.

  4. Characterising performance of environmental models

    NARCIS (Netherlands)

    Bennett, N.D.; Croke, B.F.W.; Guariso, G.; Guillaume, J.H.A.; Hamilton, S.H.; Jakeman, A.J.; Marsili-Libelli, S.; Newham, L.T.H.; Norton, J.; Perrin, C.; Pierce, S.; Robson, B.; Seppelt, R.; Voinov, A.; Fath, B.D.; Andreassian, V.

    2013-01-01

    In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus

  5. Poor transferability of species distribution models for a pelagic predator, the grey petrel, indicates contrasting habitat preferences across ocean basins.

    Science.gov (United States)

    Torres, Leigh G; Sutton, Philip J H; Thompson, David R; Delord, Karine; Weimerskirch, Henri; Sagar, Paul M; Sommer, Erica; Dilley, Ben J; Ryan, Peter G; Phillips, Richard A

    2015-01-01

    Species distribution models (SDMs) are increasingly applied in conservation management to predict suitable habitat for poorly known populations. High predictive performance of SDMs is evident in validations performed within the model calibration area (interpolation), but few studies have assessed SDM transferability to novel areas (extrapolation), particularly across large spatial scales or pelagic ecosystems. We performed rigorous SDM validation tests on distribution data from three populations of a long-ranging marine predator, the grey petrel Procellaria cinerea, to assess model transferability across the Southern Hemisphere (25-65°S). Oceanographic data were combined with tracks of grey petrels from two remote sub-Antarctic islands (Antipodes and Kerguelen) using boosted regression trees to generate three SDMs: one for each island population, and a combined model. The predictive performance of these models was assessed using withheld tracking data from within the model calibration areas (interpolation), and from a third population, Marion Island (extrapolation). Predictive performance was assessed using k-fold cross validation and point biserial correlation. The two population-specific SDMs included the same predictor variables and suggested birds responded to the same broad-scale oceanographic influences. However, all model validation tests, including of the combined model, determined strong interpolation but weak extrapolation capabilities. These results indicate that habitat use reflects both its availability and bird preferences, such that the realized distribution patterns differ for each population. The spatial predictions by the three SDMs were compared with tracking data and fishing effort to demonstrate the conservation pitfalls of extrapolating SDMs outside calibration regions. This exercise revealed that SDM predictions would have led to an underestimate of overlap with fishing effort and potentially misinformed bycatch mitigation efforts. Although

  6. Poor transferability of species distribution models for a pelagic predator, the grey petrel, indicates contrasting habitat preferences across ocean basins.

    Directory of Open Access Journals (Sweden)

    Leigh G Torres

    Full Text Available Species distribution models (SDMs are increasingly applied in conservation management to predict suitable habitat for poorly known populations. High predictive performance of SDMs is evident in validations performed within the model calibration area (interpolation, but few studies have assessed SDM transferability to novel areas (extrapolation, particularly across large spatial scales or pelagic ecosystems. We performed rigorous SDM validation tests on distribution data from three populations of a long-ranging marine predator, the grey petrel Procellaria cinerea, to assess model transferability across the Southern Hemisphere (25-65°S. Oceanographic data were combined with tracks of grey petrels from two remote sub-Antarctic islands (Antipodes and Kerguelen using boosted regression trees to generate three SDMs: one for each island population, and a combined model. The predictive performance of these models was assessed using withheld tracking data from within the model calibration areas (interpolation, and from a third population, Marion Island (extrapolation. Predictive performance was assessed using k-fold cross validation and point biserial correlation. The two population-specific SDMs included the same predictor variables and suggested birds responded to the same broad-scale oceanographic influences. However, all model validation tests, including of the combined model, determined strong interpolation but weak extrapolation capabilities. These results indicate that habitat use reflects both its availability and bird preferences, such that the realized distribution patterns differ for each population. The spatial predictions by the three SDMs were compared with tracking data and fishing effort to demonstrate the conservation pitfalls of extrapolating SDMs outside calibration regions. This exercise revealed that SDM predictions would have led to an underestimate of overlap with fishing effort and potentially misinformed bycatch mitigation

  7. The association between higher body mass index and poor school performance in high school students.

    Science.gov (United States)

    Tonetti, L; Fabbri, M; Filardi, M; Martoni, M; Natale, V

    2016-12-01

    This study aimed to examine the association between body mass index (BMI) and school performance in high school students by controlling for relevant mediators such as sleep quality, sleep duration and socioeconomic status. Thirty-seven high school students (mean age: 18.16 ± 0.44 years) attending the same school type, i.e. 'liceo scientifico' (science-based high school), were enrolled. Students' self-reported weight and height were used to calculate BMI. Participants wore an actigraph to objectively assess the quality and duration of sleep. School performance was assessed through the actual grade obtained at the final school-leaving exam, in which higher grades indicate higher performance. BMI, get-up time, mean motor activity, wake after sleep onset and number of awakenings were negatively correlated with the grade, while sleep efficiency was positively correlated. When performing a multiple regression analysis, BMI proved the only significant (negative) predictor of grade. When controlling for sleep quality, sleep duration and socioeconomic status, a higher BMI is associated with a poorer school performance in high school students. © 2015 World Obesity Federation.

  8. Tower of London test performance in children with poor arithmetic skills.

    Science.gov (United States)

    Sikora, M Darryn; Haley, Pat; Edwards, Jay; Butler, Robert W

    2002-01-01

    The Tower of London (TOL) has been used to assess executive functions in both children and adults with documented brain dysfunction. Like many other measures of executive function, it has not been widely used in the assessment of learning disabilities in children. However, if performance on the TOL discriminated among groups of children with different academic strengths and weaknesses, then it may be useful in identifying learning disability subtypes. The purpose of this study was to determine whether performance on the TOL would differ among 3 groups of children: those with arithmetic difficulties, those with reading difficulties, and those with no academic difficulties. The group with arithmetic difficulties exhibited significantly greater impairment on the TOL than either the group with reading difficulties or the group with no difficulties. The latter 2 groups performed similarly. The clinical utility of the TOL, as well as the relation between arithmetic deficits and executive functions, are discussed.

  9. Multiprocessor performance modeling with ADAS

    Science.gov (United States)

    Hayes, Paul J.; Andrews, Asa M.

    1989-01-01

    A graph managing strategy referred to as the Algorithm to Architecture Mapping Model (ATAMM) appears useful for the time-optimized execution of application algorithm graphs in embedded multiprocessors and for the performance prediction of graph designs. This paper reports the modeling of ATAMM in the Architecture Design and Assessment System (ADAS) to make an independent verification of ATAMM's performance prediction capability and to provide a user framework for the evaluation of arbitrary algorithm graphs. Following an overview of ATAMM and its major functional rules are descriptions of the ADAS model of ATAMM, methods to enter an arbitrary graph into the model, and techniques to analyze the simulation results. The performance of a 7-node graph example is evaluated using the ADAS model and verifies the ATAMM concept by substantiating previously published performance results.

  10. The Poor Performance of the Rich - Bilateral versus Multilateral Food Aid Allocation

    NARCIS (Netherlands)

    Gabbert, S.; Weikard, H.P.

    2000-01-01

    Food aid to fight hunger in developing countries is provided on a bilateral bases and by multilateral organisations. This paper examines the hypothesis that multilateral food aid is more effective than bilateral food aid. We measure donor performance under the premise that donations should reflect

  11. High burden and frailty: association with poor cognitive performance in older caregivers living in rural areas

    Directory of Open Access Journals (Sweden)

    Allan Gustavo Brigola

    2017-12-01

    Full Text Available Abstract Introduction: Older caregivers living in rural areas may be exposed to three vulnerable conditions, i.e., those related to care, their own aging, and their residence context. Objective: To analyze the association of burden and frailty with cognition performance in older caregivers in rural communities. Method: In this cross-sectional survey, 85 older caregivers who cared for dependent elders were included in this study. Global cognition (Addenbrooke's Cognitive Examination – Revised; Mini Mental State Examination, burden (Zarit Burden Interview and frailty (Fried's frailty phenotype were assessed. All ethical principles were observed. Results: Older caregivers were mostly women (76.7%; mean age was 69 years. Cognitive impairment was present in 15.3%, severe burden in 8.2%, frailty in 9.4%, and pre-frailty in 52.9% of the older caregivers. More severely burdened or frail caregivers had worse cognitive performance than those who were not, respectively (ANOVA test. Caregivers presenting a high burden level and some frailty degree (pre-frail or frail simultaneously were more likely to have a reduced global cognition performance. Conclusion: A significant number of older caregivers had low cognitive performance. Actions and resources to decrease burden and physical frailty may provide better cognition and well-being, leading to an improved quality of life and quality of the care provided by the caregivers.

  12. Poor Performance on Serial Visual Tasks in Persons with Reading Disabilities: Impaired Working Memory?

    Science.gov (United States)

    Ram-Tsur, Ronit; Faust, Miriam; Zivotofsky, Ari Z.

    2008-01-01

    The present study investigates the performance of persons with reading disabilities (PRD) on a variety of sequential visual-comparison tasks that have different working-memory requirements. In addition, mediating relationships between the sequential comparison process and attention and memory skills were looked for. Our findings suggest that PRD…

  13. Firm Sustainability Performance Index Modeling

    Directory of Open Access Journals (Sweden)

    Che Wan Jasimah Bt Wan Mohamed Radzi

    2015-12-01

    Full Text Available The main objective of this paper is to bring a model for firm sustainability performance index by applying both classical and Bayesian structural equation modeling (parametric and semi-parametric modeling. Both techniques are considered to the research data collected based on a survey directed to the China, Taiwan, and Malaysia food manufacturing industry. For estimating firm sustainability performance index we consider three main indicators include knowledge management, organizational learning, and business strategy. Based on the both Bayesian and classical methodology, we confirmed that knowledge management and business strategy have significant impact on firm sustainability performance index.

  14. Poor Memory Performance in Aged Cynomolgus Monkeys with Hippocampal Atrophy, Depletion of Amyloid Beta 1-42 and Accumulation of Tau Proteins in Cerebrospinal Fluid

    DEFF Research Database (Denmark)

    Darusman, Huda S; Pandelaki, Jacub; Mulyadi, Rahmad

    2014-01-01

    , aged cynomolgus monkeys were divided into two groups to compare high-performing (n=6) and low-performing (n=6) subjects. Both groups were tested for biomarkers related to Alzheimer's disease and their brains were scanned using structural magnetic resonance imaging. RESULTS: The subjects with poor DRT......BACKGROUND: Due to their similarities in behavior and disease pathology to humans, non-human primate models are desirable to complement small animals as models for the study of age-related dementia. MATERIALS AND METHODS: Based on their performance on delayed response task (DRT) tests of memory...... performance had evidence of atrophy in the hippocampus and cortical areas, significantly lower cerebrospinal fluid levels of amyloid beta amino acid 1-42 (pmemory...

  15. Is it Possible to (ReInsert Poor People to Development?: Models and Paradigms

    Directory of Open Access Journals (Sweden)

    José Ventura

    2016-07-01

    Full Text Available Poverty is a difficult phenomenon to solve due to its complex and multidimensional character, which is why there are many definitions and ways of measuring it. In this context, this paper has as a main goal to present a review of literature of the diverse focuses and models of reduction of poverty and to proportionate a framework of analysis and reflection for future investigations. Methodologically, the paper of literature review, which is of descriptive and theoretical nature, pays especial interest in the proposals developed by Hernando De Soto (2000 and C.K. Prahalad (2005, who illustrate hope to face an endemic problem in an international level. The richness of each focus (its complementarity and integrality defies the Management of Business because puts in evidence its potential contribution to the fight against poverty. The main result demonstrates that endogenous models, in which poor people are protagonists in the process of reinsertion to development, require two strategies: access to the markets and valorization of its wealth. Poor people require more from market (more capitalism than from social programs subsidized by the Government

  16. Origin of Androgen-Insensitive Poorly Differentiated Tumors in the Transgenic Adenocarcinoma of Mouse Prostate Model

    Directory of Open Access Journals (Sweden)

    Wendy J. Huss

    2007-11-01

    Full Text Available Following castration, the transgenic adenocarcinoma of mouse prostate (TRAMP model demonstrates rapid development of SV40-Tag-driven poorly differentiated tumors that express neuroendocrine cell markers. The cell population dynamics within the prostates of castrated TRAMP mice were characterized by analyzing the incorporation of 5-bromodeoxyuridine (BrdUrd and the expression of SV40-Tag, synaptophysin, and androgen receptor (AR. Fourteen days postcastration, the remaining epithelial cells and adenocarcinoma cells were nonproliferative and lacked detectable SV40-Tag or synaptophysin expression. In contrast, morphologically distinct intraglandular foci were identified which expressed SV40-Tag, synaptophysin, and Ki67, but that lacked AR expression. These proliferative SV40-Tag and synaptophysin-expressing intraglandular foci were associated with the rare BrdUrd-retaining cells. These foci expanded rapidly in the postcastration prostate environment, in contrast to the AR- and SV40-Tag-expressing adenocarcinoma cells that lost SV40-Tag expression and underwent apoptosis after castration. Intraglandular foci of synaptophysin-expressing cells were also observed in the prostates of intact TRAMP mice at a comparable frequency; however, they did not progress to rapidly expanding tumors until much later in the life of the mice. This suggests that the foci of neuroendocrine-like cells that express SV40-Tag and synaptophysin, but lack AR, arise independent of androgen-deprivation and represent the source of the poorly differentiated tumors that are the lethal phenotype in the TRAMP model.

  17. Job satisfaction and its modeling among township health center employees: a quantitative study in poor rural China.

    Science.gov (United States)

    Liu, Jun A; Wang, Qi; Lu, Zu X

    2010-05-10

    Job satisfaction is important to staff management of township health centers (THCs), as it is associated with organizational performance, quality of care and employee retention. The purpose of this study was to measure job satisfaction level of THC employees in poor rural China and to identify relevant features in order to provide policy advice on human resource development of health service institutions in poor regions. A self-completion questionnaire was used to assess the job satisfaction and relevant features (response rate: 90.5%) among 172 employees (i.e., clinic doctors, medico-technical workers and public health workers) of 17 THCs in Anhui and Xinjiang provinces of China. The study covered a time period of two months in 2007. The mean staff job satisfaction scored 83.3, which was in the category of "somewhat satisfied" on a scale ranging from 0 (extremely dissatisfied) to 100 (extremely satisfied) by employing Likert's transformation formula. Exploratory factor analysis (EFA) revealed eight domains involved in modeling of job satisfaction, among which, the caregivers were more satisfied with job significance (88.2), job competency (87.9) and teamwork (87.7), as compared with work reward (72.9) and working conditions (79.7). Mean job satisfaction in Xinjiang (89.7) was higher than that in Anhui (75.5). Employees of THCs have moderate job satisfactions in poor areas, which need to be raised further by improving their working conditions and reward.

  18. Job satisfaction and its modeling among township health center employees: a quantitative study in poor rural China

    Directory of Open Access Journals (Sweden)

    Lu Zu X

    2010-05-01

    Full Text Available Abstract Background Job satisfaction is important to staff management of township health centers (THCs, as it is associated with organizational performance, quality of care and employee retention. The purpose of this study was to measure job satisfaction level of THC employees in poor rural China and to identify relevant features in order to provide policy advice on human resource development of health service institutions in poor regions. Methods A self-completion questionnaire was used to assess the job satisfaction and relevant features (response rate: 90.5% among 172 employees (i.e., clinic doctors, medico-technical workers and public health workers of 17 THCs in Anhui and Xinjiang provinces of China. The study covered a time period of two months in 2007. Results The mean staff job satisfaction scored 83.3, which was in the category of "somewhat satisfied" on a scale ranging from 0 (extremely dissatisfied to 100 (extremely satisfied by employing Likert's transformation formula. Exploratory factor analysis (EFA revealed eight domains involved in modeling of job satisfaction, among which, the caregivers were more satisfied with job significance (88.2, job competency (87.9 and teamwork (87.7, as compared with work reward (72.9 and working conditions (79.7. Mean job satisfaction in Xinjiang (89.7 was higher than that in Anhui (75.5. Conclusions Employees of THCs have moderate job satisfactions in poor areas, which need to be raised further by improving their working conditions and reward.

  19. WEATHE- RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY-CONTROLLED ENVIRONMENT

    International Nuclear Information System (INIS)

    CAMERON, M.A.

    2007-01-01

    Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. All calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures

  20. WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    CAMERON, M.A.

    2007-04-16

    Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. All calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures.

  1. WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    CAMERON, M.A.

    2007-04-16

    Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. Calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures.

  2. Satellite altimetry and hydrologic modeling of poorly-gauged tropical watershed

    Science.gov (United States)

    Sulistioadi, Yohanes Budi

    proves that satellite altimetry provides a good alternative or the only means in some regions to measure the water level of medium-sized river (200--800 m width) and small lake (extent less than 1000 km 2) in Southeast Asia humid tropic with reasonable accuracy. In addition, the procedure to choose retracked Envisat altimetry water level heights via identification or selection of over water waveform shapes is reliable; therefore this study concluded that the use of waveform shape selection procedure should be a standard measure in determining qualified range measurements especially over small rivers and lakes. This study also found that Ice-1 is not necessarily the best retracker as reported by previous studies, among the four standard waveform retracking algorithms for Envisat altimetry observing hydrologic bodies. The second study modeled the response of the poorly-gauged watershed in the Southeast Asia's humid tropic through the application of Hydrologic Engineering Center -- Hydrologic Modeling System (HEC-HMS). The performance evaluation of HEC-HMS discharge estimation confirms a good match between the simulated discharges with the observed ones. As the result of precipitation data analysis, this study found that Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) is the preferred input forcing for the model, given the thorough evaluation of its relationship with field-measured precipitation data prior to its use as primary climatic forcing. This research also proposes a novel approach to process the TRMM precipitation estimation spatially through Thiessen polygon and area average hybrid method, which model the spatial distribution of TRMM data to match the spatial location of field meteorological stations. Through a simultaneous validation that compares the water level anomaly transformed from HEC-HMS simulated discharge and satellite altimetry measurement, this study found that satellite altimetry measures water level anomaly

  3. Performance lapses in children with attention-deficit/hyperactivity disorder contribute to poor reading fluency.

    Science.gov (United States)

    Jacobson, Lisa A; Ryan, Matthew; Denckla, Martha B; Mostofsky, Stewart H; Mahone, E Mark

    2013-11-01

    Children with Attention-Deficit/Hyperactivity Disorder (ADHD) demonstrate increased response variability compared with controls, which is thought to be associated with deficits in attention regulation and response control that subsequently affect performance of more cognitively demanding tasks, such as reading. The present study examined response variability during a computerized simple reaction time (RT) task in 67 children. Ex-Gaussian analyses separated the response time distribution into normal (mu and sigma) and exponential (tau) components; the association of each with reading fluency was examined. Children with ADHD had significantly slower, more variable, and more skewed RTs compared with controls. After controlling for ADHD symptom severity, tau (but not mu or mean RT) was significantly associated with reduced reading fluency, but not with single word reading accuracy. These data support the growing evidence that RT variability, but not simply slower mean response speed, is the characteristic of youth with ADHD and that longer response time latencies (tau) may be implicated in the poorer academic performance associated with ADHD.

  4. Palliative radiotherapy in patients with a poor performance status: the palliative effect is correlated with prolongation of the survival time

    International Nuclear Information System (INIS)

    Yamaguchi, Shinsaku; Ohguri, Takayuki; Matsuki, Yuichi; Yahara, Katsuya; Narisada, Hiroyuki; Imada, Hajime; Korogi, Yukunori

    2013-01-01

    The purpose of this study was to analyze the efficacy and tolerability of palliative radiotherapy (RT) in patients with a poor performance status (PS) and to evaluate the relationship between the palliative effect and survival time. One hundred and thirty-three patients with a poor PS (Eastern Cooperative Oncology Group 3 or 4) were treated with palliative RT using the three-dimensional conformal technique and retrospectively analyzed. Each patient's primary symptom treated with palliative RT as the major cause of the poor PS was evaluated using the second item of the Support Team Assessment Schedule (STAS) at the start and one week after the completion of palliative RT. One hundred and fourteen (86%) of the 133 patients completed the planned palliative radiation dose. Grade 3 acute toxicity was observed in two patients (2%) and Grade 2 acute toxicity was observed in 10 patients (9%). No Grade 2 or higher late toxicities were observed, except for Grade 3 radiation pneumonitis in one patient. Improvement in the STAS scores between pre- and post-palliative RT was recorded in 76 (61%) of the 125 patients with available scores of STAS. A significant improvement in the mean STAS score between pre- and post-palliative RT was recognized (p < 0.0001). Improvement in the STAS score was found to be the most statistically significant prognostic factor for overall survival after palliative RT in both the multivariate and univariate analyses. The median overall survival time in the patients with an improvement in the STAS score was 6.4 months, while that in the patients without improvement was 2.4 months (p < 0.0005). Palliative RT in patients with a poor PS provides symptomatic benefits in more than half of patients without inducing severe toxicities. The palliative effect is strongly correlated with prolongation of the survival time and may contribute to improving the remaining survival time in patients with metastatic/advanced cancer with a poor PS

  5. Causes of poor sealant performance in soil-gas-resistant foundations

    International Nuclear Information System (INIS)

    Scott, A.

    1994-01-01

    Sealants for radon-resistant foundation construction must seal the gap between concrete sections. Modern sealants have such low permeability that seal performance depends only on the permeability of the material that contacts the sealant. The surface permeability of concrete walls and floors was measured by a specially designed permeameter, which measures the airflow induced by a pressure difference across a temporary test seal applied to the surface. The permeability of bulk concrete is about 10 -15 m 2 . Areas free of surface defects had surface permeability ranging from 10 -14 to 10 -16 m 2 . However, surface defects are common on concrete wall surfaces, which increase the permeability to >10 -12 m 2 , too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Radon-resistant seals require either extended contact widths or mechanical removal of the surface layer and defects. (au) (4 refs.)

  6. Pushover, Response Spectrum and Time History Analyses of Safe Rooms in a Poor Performance Masonry Building

    International Nuclear Information System (INIS)

    Mazloom, M.

    2008-01-01

    The idea of safe room has been developed for decreasing the earthquake casualties in masonry buildings. The information obtained from the previous ground motions occurring in seismic zones expresses the lack of enough safety of these buildings against earthquakes. For this reason, an attempt has been made to create some safe areas inside the existing masonry buildings, which are called safe rooms. The practical method for making these safe areas is to install some prefabricated steel frames in some parts of the existing structure. These frames do not carry any service loads before an earthquake. However, if a devastating earthquake happens and the load bearing walls of the building are destroyed, some parts of the floors, which are in the safe areas, will fall on the roof of the installed frames and the occupants who have sheltered there will survive. This paper presents the performance of these frames located in a destroying three storey masonry building with favorable conclusions. In fact, the experimental pushover diagram of the safe room located at the ground-floor level of this building is compared with the analytical results and it is concluded that pushover analysis is a good method for seismic performance evaluation of safe rooms. For time history analysis the 1940 El Centro, the 2003 Bam, and the 1990 Manjil earthquake records with the maximum peak accelerations of 0.35g were utilized. Also the design spectrum of Iranian Standard No. 2800-05 for the ground kind 2 is used for response spectrum analysis. The results of time history, response spectrum and pushover analyses show that the strength and displacement capacity of the steel frames are adequate to accommodate the distortions generated by seismic loads and aftershocks properly

  7. Too much of a good thing? Elevated baseline sleep spindles predict poor avoidance performance in rats.

    Science.gov (United States)

    Fogel, S M; Smith, C T; Beninger, R J

    2010-03-10

    Sleep spindles may be involved in synaptic plasticity. Learning-dependent increases in spindles have been observed in both humans and rats. In humans, the innate (i.e., baseline) number of spindles correlate with measures of academic potential such as Intelligence Quotient (IQ) tests. The present study investigated if spindles predict whether rats are able to learn to make avoidance responses in the two-way shuttle task. Baseline recordings were taken continuously for 24h prior to training on the two-way shuttle task for 50trials/day for two days followed by a 25 trial re-test on the third day. At re-test, rats were categorized into learners (n=16) or non-learners (n=21). Groups did not differ in baseline duration of rapid eye movement sleep, slow wave sleep, wake or spindle density. For combined groups, spindle density in the 21 to 24-hour period but not at any other period during baseline was negatively correlated with shuttle task performance at re-test. Conversely, the learning-related change in spindle density in the 21 to 24-hour period, but not at any other time after the first training session was positively correlated with shuttle task performance. Rats in the non-learning condition have a higher number of spindles at baseline, which is unaffected by training. On the other hand, learning rats have fewer spindles at baseline, but have a learning-related increase in spindles. Extreme spindle activity and high spindle density have been observed in humans with learning disabilities. Results suggest that while spindles may be involved in memory consolidation, in some cases, high levels of spindles prior to training may be maladaptive. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Sleep disordered breathing symptoms and daytime sleepiness are associated with emotional problems and poor school performance in children.

    Science.gov (United States)

    Liu, Jianghong; Liu, Xianchen; Ji, Xiaopeng; Wang, Yingjie; Zhou, Guoping; Chen, Xinyin

    2016-08-30

    This study examined the prevalence of sleep disordered breathing (SDB) symptoms and their associations with daytime sleepiness, emotional problems, and school performance in Chinese children. Participants included 3979 children (10.99±0.99 years old) from four elementary schools in Jintan City, Jiangsu Province, China. Children completed a self-administered questionnaire on sleep behavior and emotional problems, while parents completed the Child Sleep Habit Questionnaire (CSHQ). SDB symptoms included 3 items: loud snoring, stopped breathing, and snorting/gasping during sleep. Teachers rated the children's school performance. The prevalence rates of parent- and self-reported SDB symptoms were 17.2% and 10.1% for "sometimes" and 8.9% and 5.6% for "usually". SDB symptoms, more prevalent in boys than in girls, increased the risks for depression, loneliness, and poor school performance. Daytime sleepiness mediated the relationship between SDB symptoms and depression, loneliness, and poor school performance. This study suggests the importance of early screening and intervention of SDB and daytime sleepiness in child behavioral and cognitive development. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. MODELING SUPPLY CHAIN PERFORMANCE VARIABLES

    Directory of Open Access Journals (Sweden)

    Ashish Agarwal

    2005-01-01

    Full Text Available In order to understand the dynamic behavior of the variables that can play a major role in the performance improvement in a supply chain, a System Dynamics-based model is proposed. The model provides an effective framework for analyzing different variables affecting supply chain performance. Among different variables, a causal relationship among different variables has been identified. Variables emanating from performance measures such as gaps in customer satisfaction, cost minimization, lead-time reduction, service level improvement and quality improvement have been identified as goal-seeking loops. The proposed System Dynamics-based model analyzes the affect of dynamic behavior of variables for a period of 10 years on performance of case supply chain in auto business.

  10. Poor Performance on a Preoperative Cognitive Screening Test Predicts Postoperative Complications in Older Orthopedic Surgical Patients.

    Science.gov (United States)

    Culley, Deborah J; Flaherty, Devon; Fahey, Margaret C; Rudolph, James L; Javedan, Houman; Huang, Chuan-Chin; Wright, John; Bader, Angela M; Hyman, Bradley T; Blacker, Deborah; Crosby, Gregory

    2017-11-01

    The American College of Surgeons and the American Geriatrics Society have suggested that preoperative cognitive screening should be performed in older surgical patients. We hypothesized that unrecognized cognitive impairment in patients without a history of dementia is a risk factor for development of postoperative complications. We enrolled 211 patients 65 yr of age or older without a diagnosis of dementia who were scheduled for an elective hip or knee replacement. Patients were cognitively screened preoperatively using the Mini-Cog and demographic, medical, functional, and emotional/social data were gathered using standard instruments or review of the medical record. Outcomes included discharge to place other than home (primary outcome), delirium, in-hospital medical complications, hospital length-of-stay, 30-day emergency room visits, and mortality. Data were analyzed using univariate and multivariate analyses. Fifty of 211 (24%) patients screened positive for probable cognitive impairment (Mini-Cog less than or equal to 2). On age-adjusted multivariate analysis, patients with a Mini-Cog score less than or equal to 2 were more likely to be discharged to a place other than home (67% vs. 34%; odds ratio = 3.88, 95% CI = 1.58 to 9.55), develop postoperative delirium (21% vs. 7%; odds ratio = 4.52, 95% CI = 1.30 to 15.68), and have a longer hospital length of stay (hazard ratio = 0.63, 95% CI = 0.42 to 0.95) compared to those with a Mini-Cog score greater than 2. Many older elective orthopedic surgical patients have probable cognitive impairment preoperatively. Such impairment is associated with development of delirium postoperatively, a longer hospital stay, and lower likelihood of going home upon hospital discharge.

  11. Effects of Motivation: Rewarding Hackers for Undetected Attacks Cause Analysts to Perform Poorly.

    Science.gov (United States)

    Maqbool, Zahid; Makhijani, Nidhi; Pammi, V S Chandrasekhar; Dutt, Varun

    2017-05-01

    The aim of this study was to determine how monetary motivations influence decision making of humans performing as security analysts and hackers in a cybersecurity game. Cyberattacks are increasing at an alarming rate. As cyberattacks often cause damage to existing cyber infrastructures, it is important to understand how monetary rewards may influence decision making of hackers and analysts in the cyber world. Currently, only limited attention has been given to this area. In an experiment, participants were randomly assigned to three between-subjects conditions ( n = 26 for each condition): equal payoff, where the magnitude of monetary rewards for hackers and defenders was the same; rewarding hacker, where the magnitude of monetary reward for hacker's successful attack was 10 times the reward for analyst's successful defense; and rewarding analyst, where the magnitude of monetary reward for analyst's successful defense was 10 times the reward for hacker's successful attack. In all conditions, half of the participants were human hackers playing against Nash analysts and half were human analysts playing against Nash hackers. Results revealed that monetary rewards for human hackers and analysts caused a decrease in attack and defend actions compared with the baseline. Furthermore, rewarding human hackers for undetected attacks made analysts deviate significantly from their optimal behavior. If hackers are rewarded for their undetected attack actions, then this causes analysts to deviate from optimal defend proportions. Thus, analysts need to be trained not become overenthusiastic in defending networks. Applications of our results are to networks where the influence of monetary rewards may cause information theft and system damage.

  12. Upper urinary tract stone disease in patients with poor performance status: active stone removal or conservative management?

    Science.gov (United States)

    Yamashita, Shimpei; Kohjimoto, Yasuo; Hirabayashi, Yasuo; Iguchi, Takashi; Iba, Akinori; Higuchi, Masatoshi; Koike, Hiroyuki; Wakamiya, Takahito; Nishizawa, Satoshi; Hara, Isao

    2017-11-16

    It remains controversial as to whether active stone removal should be performed in patients with poor performance status because of their short life expectancy and perioperative risks. Our objectives were to evaluate treatment outcomes of active stone removal in patients with poor performance status and to compare life prognosis with those managed conservatively. We retrospectively reviewed 74 patients with Eastern Cooperative Oncology Group performance status 3 or 4 treated for upper urinary tract calculi at our four hospitals between January 2009 and March 2016. Patients were classified into either surgical treatment group or conservative management group based on the presence of active stone removal. Stone-free rate and perioperative complications in surgical treatment group were reviewed. In addition, we compared overall survival and stone-specific survival between the two groups. Cox proportional hazards analysis was performed to investigate predictors of overall survival and stone-specific survival. Fifty-two patients (70.3%) underwent active stone removal (surgical treatment group) by extracorporeal shock wave lithotripsy (n = 6), ureteroscopy (n = 39), percutaneous nephrolithotomy (n = 6) or nephrectomy (n = 1). The overall stone-free rate was 78.8% and perioperative complication was observed in nine patients (17.3%). Conservative treatment was undergone by 22 patients (29.7%) (conservative management group). Two-year overall survival rates in surgical treatment and conservative management groups were 88.0% and 38.4%, respectively (p performance status could be performed safely and effectively. Compared to conservative management, surgical stone treatment achieved longer overall survival and stone-specific survival.

  13. Air Conditioner Compressor Performance Model

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ning; Xie, YuLong; Huang, Zhenyu

    2008-09-05

    During the past three years, the Western Electricity Coordinating Council (WECC) Load Modeling Task Force (LMTF) has led the effort to develop the new modeling approach. As part of this effort, the Bonneville Power Administration (BPA), Southern California Edison (SCE), and Electric Power Research Institute (EPRI) Solutions tested 27 residential air-conditioning units to assess their response to delayed voltage recovery transients. After completing these tests, different modeling approaches were proposed, among them a performance modeling approach that proved to be one of the three favored for its simplicity and ability to recreate different SVR events satisfactorily. Funded by the California Energy Commission (CEC) under its load modeling project, researchers at Pacific Northwest National Laboratory (PNNL) led the follow-on task to analyze the motor testing data to derive the parameters needed to develop a performance models for the single-phase air-conditioning (SPAC) unit. To derive the performance model, PNNL researchers first used the motor voltage and frequency ramping test data to obtain the real (P) and reactive (Q) power versus voltage (V) and frequency (f) curves. Then, curve fitting was used to develop the P-V, Q-V, P-f, and Q-f relationships for motor running and stalling states. The resulting performance model ignores the dynamic response of the air-conditioning motor. Because the inertia of the air-conditioning motor is very small (H<0.05), the motor reaches from one steady state to another in a few cycles. So, the performance model is a fair representation of the motor behaviors in both running and stalling states.

  14. A framework for streamflow prediction in the world's most severely data-limited regions: Test of applicability and performance in a poorly-gauged region of China

    Science.gov (United States)

    Alipour, M. H.; Kibler, Kelly M.

    2018-02-01

    A framework methodology is proposed for streamflow prediction in poorly-gauged rivers located within large-scale regions of sparse hydrometeorologic observation. A multi-criteria model evaluation is developed to select models that balance runoff efficiency with selection of accurate parameter values. Sparse observed data are supplemented by uncertain or low-resolution information, incorporated as 'soft' data, to estimate parameter values a priori. Model performance is tested in two catchments within a data-poor region of southwestern China, and results are compared to models selected using alternative calibration methods. While all models perform consistently with respect to runoff efficiency (NSE range of 0.67-0.78), models selected using the proposed multi-objective method may incorporate more representative parameter values than those selected by traditional calibration. Notably, parameter values estimated by the proposed method resonate with direct estimates of catchment subsurface storage capacity (parameter residuals of 20 and 61 mm for maximum soil moisture capacity (Cmax), and 0.91 and 0.48 for soil moisture distribution shape factor (B); where a parameter residual is equal to the centroid of a soft parameter value minus the calibrated parameter value). A model more traditionally calibrated to observed data only (single-objective model) estimates a much lower soil moisture capacity (residuals of Cmax = 475 and 518 mm and B = 1.24 and 0.7). A constrained single-objective model also underestimates maximum soil moisture capacity relative to a priori estimates (residuals of Cmax = 246 and 289 mm). The proposed method may allow managers to more confidently transfer calibrated models to ungauged catchments for streamflow predictions, even in the world's most data-limited regions.

  15. High Intracellular Seed Train BiP Levels Correlate with Poor Production Culture Performance in CHO Cells.

    Science.gov (United States)

    Tung, Meg; Tang, Danming; Wang, Szu-Han; Zhan, Dejin; Kiplinger, Karen; Pan, Shu; Jing, Yifeng; Shen, Amy; Ahyow, Patrick; Snedecor, Brad; Gawlitzek, Martin; Misaghi, Shahram

    2018-04-10

    Consistent cell culture performance is a prerequisite to ensure product quality consistency and achieve productivity goals for the manufacture of recombinant protein therapeutics, including monoclonal antibodies. Here we report a peculiar observation where high levels of intracellular BiP in seed train cultures are consistently predictive of poor cell culture performance in the subsequent inoculum and production cultures for a monoclonal antibody produced in CHO cells. Our investigations suggest that in this cell line the high intracellular BiP levels in the seed train are triggered by a slightly lower culture pH, which interferes with proper antibody folding and secretion. While the seed train culture does not display any obvious signs of the problem at slightly lower culture pH, inoculum trains and production cultures sourced from these low pH seed trains display significantly lower cell growth and cell size. High intracellular BiP levels may interfere with UPR signaling, thereby hampering a proper and timely UPR response in the production media. Studies of other problematic cell lines have shown a similar correlation between intracellular BiP accumulation and poor production performance. We believe intracellular BiP levels in seed train should hence be low in order to increase the success rate in production. This article is protected by copyright. All rights reserved.

  16. Poor title--poor manuscript?

    Science.gov (United States)

    Gjersvik, Petter; Gulbrandsen, Pål; Aasheim, Erlend T; Nylenna, Magne

    2013-12-10

    The title of a scientific article is important for several reasons. Does the title of a manuscript submitted for publication in a medical journal reflect the quality of the manuscript itself? We prepared criteria for poor, fair and good titles and tested them in pilot studies. All manuscripts submitted to the Journal of the Norwegian Medical Association during the period 1 September 2009-31 August 2011 as original articles (n = 211) or review articles (n = 110) were recorded. The quality of the titles was scored by two former editors. Primary outcome measures were rejection rates and odds ratio for rejection of manuscripts with a poor title compared to those with a good title. For original articles, the rejection rate for manuscripts with a poor, fair or good title amounted to 88%, 73% and 61% (p = 0.002) respectively, and for review articles 83%, 56% and 38% (p title compared to those with a good title was 4.6 (95% CI: 1.7-12.3) for original articles and 8.2 (95% CI: 2.6-26.4) for review articles. In a logistic regression model, the quality of the title explained 14% and 27% of the variance in outcome for original articles and review articles respectively. In this study, a poor manuscript title was significantly associated with manuscript rejection. This indicates that the quality of the title often reflects the quality of the manuscript itself.

  17. Poor performance of fine motor activity among biological parents of children with attention deficit/hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Ni Chun Hung

    2016-12-01

    Full Text Available It has been proposed that the dopaminergic system and heritability may play roles in attention deficit/hyperactivity disorder (ADHD. We assessed the performance of healthy parents of children with ADHD in the finger tapping test (FTT in this study, which is a reliable test and sensitive to central dopamine activity. A total of 16 parents of children with ADHD and 32 controls were enrolled. The FTT was conducted. The 16 healthy parents of children with ADHD exhibited a significantly poorer performance in the FTT, using the nondominant hand, than the 32 healthy controls. This finding indicated that poor motor function could be a potential characteristic in parents of offspring with ADHD.

  18. Association of pediatric obstructive sleep apnea with poor academic performance: A school-based study from India

    Science.gov (United States)

    Goyal, Abhishek; Pakhare, Abhijit P; Bhatt, Girish C; Choudhary, Bharat; Patil, Rajesh

    2018-01-01

    Background: Pediatric obstructive sleep apnea (OSA) is a highly prevalent but often neglected disorder. There is paucity of reports on the prevalence of pediatric OSA from India. This study was done to estimate the prevalence of OSA in school children aged 5–10 years and its association with academic performance. Methodology: This school-based cross-sectional epidemiological study was conducted from July 2015 to November 2015. A questionnaire seeking information on sociodemographic variables, school performance, sleeping pattern, and a validated 22-item pediatrics sleep-related breathing disorder (SRBD) scale was distributed to 1820 pupils in three primary schools. The prevalence of OSA (defined as SRBD score >33%) was reported as proportion and its 95% confidence interval (CI). Results: We received 1520 questionnaires out of 1820 distributed and of which 1346 were complete and were analyzed. The prevalence of OSA among children in our study was 9.6% (95% CI: 8.1%–11.7%). On multivariate analysis, working mother (adjusted odds ratio [OR]: 1.8; 95% CI: 1.2–2.7), sleep bruxism (adjusted OR: 1.7; 95% CI: 1.1–2.6), and sleep talking (adjusted OR: 3.0; 95% CI: 1.9–4.7) were found to be independently associated with OSA. Students with positive SRBD were more prone to nocturnal enuresis (NE) (OR 3.48; 95% CI 2.27–5.26) and poor academic performance in all subjects. Conclusion: OSA is highly prevalent (9.6%) in Indian children. OSA is associated with NE and poor academic performance in all subjects. This study found association of maternal occupation and OSA which needs to be confirmed in larger studies. PMID:29487248

  19. Association of pediatric obstructive sleep apnea with poor academic performance: A school-based study from India.

    Science.gov (United States)

    Goyal, Abhishek; Pakhare, Abhijit P; Bhatt, Girish C; Choudhary, Bharat; Patil, Rajesh

    2018-01-01

    Pediatric obstructive sleep apnea (OSA) is a highly prevalent but often neglected disorder. There is paucity of reports on the prevalence of pediatric OSA from India. This study was done to estimate the prevalence of OSA in school children aged 5-10 years and its association with academic performance. This school-based cross-sectional epidemiological study was conducted from July 2015 to November 2015. A questionnaire seeking information on sociodemographic variables, school performance, sleeping pattern, and a validated 22-item pediatrics sleep-related breathing disorder (SRBD) scale was distributed to 1820 pupils in three primary schools. The prevalence of OSA (defined as SRBD score >33%) was reported as proportion and its 95% confidence interval (CI). We received 1520 questionnaires out of 1820 distributed and of which 1346 were complete and were analyzed. The prevalence of OSA among children in our study was 9.6% (95% CI: 8.1%-11.7%). On multivariate analysis, working mother (adjusted odds ratio [OR]: 1.8; 95% CI: 1.2-2.7), sleep bruxism (adjusted OR: 1.7; 95% CI: 1.1-2.6), and sleep talking (adjusted OR: 3.0; 95% CI: 1.9-4.7) were found to be independently associated with OSA. Students with positive SRBD were more prone to nocturnal enuresis (NE) (OR 3.48; 95% CI 2.27-5.26) and poor academic performance in all subjects. OSA is highly prevalent (9.6%) in Indian children. OSA is associated with NE and poor academic performance in all subjects. This study found association of maternal occupation and OSA which needs to be confirmed in larger studies.

  20. Association of pediatric obstructive sleep apnea with poor academic performance: A school-based study from India

    Directory of Open Access Journals (Sweden)

    Abhishek Goyal

    2018-01-01

    Full Text Available Background: Pediatric obstructive sleep apnea (OSA is a highly prevalent but often neglected disorder. There is paucity of reports on the prevalence of pediatric OSA from India. This study was done to estimate the prevalence of OSA in school children aged 5–10 years and its association with academic performance. Methodology: This school-based cross-sectional epidemiological study was conducted from July 2015 to November 2015. A questionnaire seeking information on sociodemographic variables, school performance, sleeping pattern, and a validated 22-item pediatrics sleep-related breathing disorder (SRBD scale was distributed to 1820 pupils in three primary schools. The prevalence of OSA (defined as SRBD score >33% was reported as proportion and its 95% confidence interval (CI. Results: We received 1520 questionnaires out of 1820 distributed and of which 1346 were complete and were analyzed. The prevalence of OSA among children in our study was 9.6% (95% CI: 8.1%–11.7%. On multivariate analysis, working mother (adjusted odds ratio [OR]: 1.8; 95% CI: 1.2–2.7, sleep bruxism (adjusted OR: 1.7; 95% CI: 1.1–2.6, and sleep talking (adjusted OR: 3.0; 95% CI: 1.9–4.7 were found to be independently associated with OSA. Students with positive SRBD were more prone to nocturnal enuresis (NE (OR 3.48; 95% CI 2.27–5.26 and poor academic performance in all subjects. Conclusion: OSA is highly prevalent (9.6% in Indian children. OSA is associated with NE and poor academic performance in all subjects. This study found association of maternal occupation and OSA which needs to be confirmed in larger studies.

  1. Oral narrative context effects on poor readers' spoken language performance: story retelling, story generation, and personal narratives.

    Science.gov (United States)

    Westerveld, Marleen F; Gillon, Gail T

    2010-04-01

    This investigation explored the effects of oral narrative elicitation context on children's spoken language performance. Oral narratives were produced by a group of 11 children with reading disability (aged between 7;11 and 9;3) and an age-matched control group of 11 children with typical reading skills in three different contexts: story retelling, story generation, and personal narratives. In the story retelling condition, the children listened to a story on tape while looking at the pictures in a book, before being asked to retell the story without the pictures. In the story generation context, the children were shown a picture containing a scene and were asked to make up their own story. Personal narratives were elicited with the help of photos and short narrative prompts. The transcripts were analysed at microstructure level on measures of verbal productivity, semantic diversity, and morphosyntax. Consistent with previous research, the results revealed no significant interactions between group and context, indicating that the two groups of children responded to the type of elicitation context in a similar way. There was a significant group effect, however, with the typical readers showing better performance overall on measures of morphosyntax and semantic diversity. There was also a significant effect of elicitation context with both groups of children producing the longest, linguistically most dense language samples in the story retelling context. Finally, the most significant differences in group performance were observed in the story retelling condition, with the typical readers outperforming the poor readers on measures of verbal productivity, number of different words, and percent complex sentences. The results from this study confirm that oral narrative samples can distinguish between good and poor readers and that the story retelling condition may be a particularly useful context for identifying strengths and weaknesses in oral narrative performance.

  2. Vision-Based Autonomous Underwater Vehicle Navigation in Poor Visibility Conditions Using a Model-Free Robust Control

    Directory of Open Access Journals (Sweden)

    Ricardo Pérez-Alcocer

    2016-01-01

    Full Text Available This paper presents a vision-based navigation system for an autonomous underwater vehicle in semistructured environments with poor visibility. In terrestrial and aerial applications, the use of visual systems mounted in robotic platforms as a control sensor feedback is commonplace. However, robotic vision-based tasks for underwater applications are still not widely considered as the images captured in this type of environments tend to be blurred and/or color depleted. To tackle this problem, we have adapted the lαβ color space to identify features of interest in underwater images even in extreme visibility conditions. To guarantee the stability of the vehicle at all times, a model-free robust control is used. We have validated the performance of our visual navigation system in real environments showing the feasibility of our approach.

  3. Age-related Changes in Lateral Entorhinal and CA3 Neuron Allocation Predict Poor Performance on Object Discrimination

    Directory of Open Access Journals (Sweden)

    Andrew P. Maurer

    2017-06-01

    Full Text Available Age-related memory deficits correlate with dysfunction in the CA3 subregion of the hippocampus, which includes both hyperactivity and overly rigid activity patterns. While changes in intrinsic membrane currents and interneuron alterations are involved in this process, it is not known whether alterations in afferent input to CA3 also contribute. Neurons in layer II of the lateral entorhinal cortex (LEC project directly to CA3 through the perforant path, but no data are available regarding the effects of advanced age on LEC activity and whether these activity patterns update in response to environmental change. Furthermore, it is not known the extent to which age-related deficits in sensory discrimination relate to the inability of aged CA3 neurons to update in response to new environments. Young and aged rats were pre-characterized on a LEGO© object discrimination task, comparable to behavioral tests in humans in which CA3 hyperactivity has been linked to impairments. The cellular compartment analysis of temporal activity with fluorescence in situ hybridization for the immediate-early gene Arc was then used to identify the principal cell populations that were active during two distinct epochs of random foraging in different environments. This approach enabled the extent to which rats could discriminate two similar objects to be related to the ability of CA3 neurons to update across different environments. In both young and aged rats, there were animals that performed poorly on the LEGO object discrimination task. In the aged rats only, however, the poor performers had a higher percent of CA3 neurons that were active during random foraging in a novel environment, but this is not related to the ability of CA3 neurons to remap when the environment changed. Afferent neurons to CA3 in LEC, as identified with the retrograde tracer choleratoxin B (CTB, also showed a higher percentage of cells that were positive for Arc mRNA in aged poor performing rats

  4. Born early and born poor: An eco-bio-developmental model for poverty and preterm birth.

    Science.gov (United States)

    Brumberg, H L; Shah, S I

    2015-01-01

    Poverty is associated with adverse long-term cognitive outcomes in children. Poverty is also linked with preterm delivery which, in turn, is associated with adverse cognitive outcomes. However, the extent of the effect of poverty on preterm delivery, as well as proposed mechanisms by which they occur, have not been well described. Further, the impact of poverty on preterm school readiness has not been reviewed. As the childhood poverty level continues to increase in the U.S., we examine the evidence around physiological, neurological, cognitive and learning outcomes associated with prematurity in the context of poverty. We use the evidence gathered to suggest an Eco-Bio-Developmental model, emphasizing poverty as a toxic stress which predisposes preterm birth and which, via epigenetic forces, can continue into the next generation. Continued postnatal social disadvantage for these developmentally high-risk preterm infants is strongly linked with poor neurodevelopmental outcomes, decreased school readiness, and decreased educational attainment which can perpetuate the poverty cycle. We suggest social remedies aimed at decreasing the impact of poverty on mothers, fathers, and children which may be effective in reducing the burden of preterm birth.

  5. Influence of residual catalyst on the properties of conjugated polyphenylenevinylene materials: Palladium nanoparticles and poor electrical performance

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Nyberg, R.B.; Jørgensen, M.

    2004-01-01

    The synthesis of conjugated polymer materials using palladium catalysis was shown to result in a contamination of the polymer product with palladium nanoparticles that were difficult to detect and remove. The particle size was on the order of 20 nm, as evidenced by transmission electron microscopy...... (TEM). Further, electron spectroscopy for chemical analysis (ESCA), powder X-ray diffraction, and scanning electron microscopy (SEM) were employed to establish the chemical and physical nature of the catalyst remnants. We demonstrate the identity of many physical and chemical properties of the same...... polymer material prepared by two different routes: the palladium route and the condensation route. The performance in a device application of the two polymer materials was, however, very different, and the palladium route was demonstrated to give poor films with low breakdown voltages and short circuits....

  6. A new risk scoring model for prediction of poor coronary collateral circulation in acute non-ST-elevation myocardial infarction.

    Science.gov (United States)

    İleri, Mehmet; Güray, Ümit; Yetkin, Ertan; Gürsoy, Havva Tuğba; Bayır, Pınar Türker; Şahin, Deniz; Elalmış, Özgül Uçar; Büyükaşık, Yahya

    2016-01-01

    We aimed to investigate the clinical features associated with development of coronary collateral circulation (CCC) in patients with acute non-ST-elevation myocardial infarction (NSTEMI) and to develop a scoring model for predicting poor collateralization at hospital admission. The study enrolled 224 consecutive patients with NSTEMI admitted to our coronary care unit. Patients were divided into poor (grade 0 and 1) and good (grade 2 and 3) CCC groups. In logistic regression analysis, presence of diabetes mellitus, total white blood cell (WBC) and neutrophil counts and neutrophil to lymphocyte ratio (NLR) were found as independent positive predictors of poor CCC, whereas older age (≥ 70 years) emerged as a negative indicator. The final scoring model was based on 5 variables which were significant at p risk score ≤ 1, 29 had good CCC (with a 97% negative predictive value). On the other hand, 139 patients had risk score ≥ 4; out of whom, 130 (with a 93.5% positive predictive value) had poor collateralization. Sensitivity and specificity of the model in predicting poor collateralization in patients with scores ≤ 1 and ≥ 4 were 99.2% (130/131) and +76.3 (29/38), respectively. This study represents the first prediction model for degree of coronary collateralization in patients with acute NSTEMI.

  7. Item Response Theory Models for Performance Decline during Testing

    Science.gov (United States)

    Jin, Kuan-Yu; Wang, Wen-Chung

    2014-01-01

    Sometimes, test-takers may not be able to attempt all items to the best of their ability (with full effort) due to personal factors (e.g., low motivation) or testing conditions (e.g., time limit), resulting in poor performances on certain items, especially those located toward the end of a test. Standard item response theory (IRT) models fail to…

  8. The Association of Poor Academic Performance with Tic Disorders: A Longitudinal, Mainstream School-Based Population Study.

    Science.gov (United States)

    Cubo, Esther; Gonzalez, Cristina; Ausin, Vanesa; Delgado, Vanesa; Saez, Sara; Calvo, Sara; Garcia Soto, Xose; Cordero, José; Kompoliti, Katie; Louis, Elan D; de la Fuente Anuncibay, Raquel

    2017-01-01

    Little is known about the academic performance of students with tic disorders (TD). Our aim was to investigate the association of TD and poor academic performance over time. Longitudinal, observational study of mainstream schoolchildren comparing grade retention (GR) and learning disorders (LD) in students with vs. without TD between 2010 and 2014. Students with vs. without TD based on DSM-IV-TR criteria, or with vs. without GR and LD were compared in terms of comorbidities, school, and environmental characteristics. The association of TD with GR was analyzed using hazard ratios (HRs) with 95% CIs, and with LD using logistic regression analysis [Odds ratio (OR)]. Two hundred fifty-eight students were included (mean age 14.0 ± 1.71 years, 143 [55.4%] males). The incident rate for TD and GR was 2.6 and 3.3 per 100 persons-year, respectively. LD found in 21 (9.9%) students was associated with TD (OR 11.62, 95% CI 2.21-60.90, p = 0.004), and attention deficit hyperactivity disorder (ADHD; OR 6.63, 95% CI 1.55-28.37, p = 0.01). Low psychological support (HRs 12.79, 95% CI 3.39-48.17) and low sport participation (HRs 6.41, 95% CI 1.54-26.78) were risk factors for GR. TD was associated with academic difficulties, namely, LD in conjunction with ADHD but not GR. The diagnosis of TD and comorbidities, and the initiation of proper treatment could have a favorable impact on school performance, and consequently on social development. © 2017 S. Karger AG, Basel.

  9. Poor trail making test performance is directly associated with altered dual task prioritization in the elderly--baseline results from the TREND study.

    Directory of Open Access Journals (Sweden)

    Markus A Hobert

    Full Text Available BACKGROUND: Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance--which specifically measures cognitive flexibility and working memory--and dual task costs, a measure of prioritization. METHODOLOGY AND PRINCIPAL FINDINGS: Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders, 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A. The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range -6 to 58% compared to the good performers (17%; -16 to 43%; p<0.001. To the contrary, the proportion of the poor TMT performance group that made calculation errors under the dual tasking situation was lower than under the single task situation, but higher in the good TMT performance group (poor performers, -1.6%; good performers, +3%; p = 0.035. CONCLUSION: Under most challenging conditions, the elderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive

  10. Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

    OpenAIRE

    Stancliffe, Richard J.; Kennedy, Catherine R.; Lau, Herbert H. B.; Beers, Timothy C.

    2013-01-01

    Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently, Kinman et al. discovered that the highly carbon- and barium-enriched metal-poor star SDSS J1707+58 is in fact an RR Lyrae pulsator. This gives us an object in a definite evolutionary state where the effects of dilution of material during the Main Sequence ...

  11. Behavior model for performance assessment.

    Energy Technology Data Exchange (ETDEWEB)

    Borwn-VanHoozer, S. A.

    1999-07-23

    Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing a basic understanding of the foundation of how the behavior was predicated through a decision making strategy process, predicative models are overall inefficient in their analysis of the means by which behavior was generated. What is seen is the end result.

  12. Behavior model for performance assessment

    International Nuclear Information System (INIS)

    Brown-VanHoozer, S. A.

    1999-01-01

    Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing a basic understanding of the foundation of how the behavior was predicated through a decision making strategy process, predicative models are overall inefficient in their analysis of the means by which behavior was generated. What is seen is the end result

  13. Funnel plot control limits to identify poorly performing healthcare providers when there is uncertainty in the value of the benchmark.

    Science.gov (United States)

    Manktelow, Bradley N; Seaton, Sarah E; Evans, T Alun

    2016-12-01

    There is an increasing use of statistical methods, such as funnel plots, to identify poorly performing healthcare providers. Funnel plots comprise the construction of control limits around a benchmark and providers with outcomes falling outside the limits are investigated as potential outliers. The benchmark is usually estimated from observed data but uncertainty in this estimate is usually ignored when constructing control limits. In this paper, the use of funnel plots in the presence of uncertainty in the value of the benchmark is reviewed for outcomes from a Binomial distribution. Two methods to derive the control limits are shown: (i) prediction intervals; (ii) tolerance intervals Tolerance intervals formally include the uncertainty in the value of the benchmark while prediction intervals do not. The probability properties of 95% control limits derived using each method were investigated through hypothesised scenarios. Neither prediction intervals nor tolerance intervals produce funnel plot control limits that satisfy the nominal probability characteristics when there is uncertainty in the value of the benchmark. This is not necessarily to say that funnel plots have no role to play in healthcare, but that without the development of intervals satisfying the nominal probability characteristics they must be interpreted with care. © The Author(s) 2014.

  14. Precision Hypofractionated Radiation Therapy in Poor Performing Patients With Non-Small Cell Lung Cancer: Phase 1 Dose Escalation Trial.

    Science.gov (United States)

    Westover, Kenneth D; Loo, Billy W; Gerber, David E; Iyengar, Puneeth; Choy, Hak; Diehn, Maximilian; Hughes, Randy; Schiller, Joan; Dowell, Jonathan; Wardak, Zabi; Sher, David; Christie, Alana; Xie, Xian-Jin; Corona, Irma; Sharma, Akanksha; Wadsworth, Margaret E; Timmerman, Robert

    2015-09-01

    Treatment regimens for locally advanced non-small cell lung cancer (NSCLC) give suboptimal clinical outcomes. Technological advancements such as radiation therapy, the backbone of most treatment regimens, may enable more potent and effective therapies. The objective of this study was to escalate radiation therapy to a tumoricidal hypofractionated dose without exceeding the maximally tolerated dose (MTD) in patients with locally advanced NSCLC. Patients with stage II to IV or recurrent NSCLC and Eastern Cooperative Oncology Group performance status of 2 or greater and not candidates for surgical resection, stereotactic radiation, or concurrent chemoradiation were eligible. Highly conformal radiation therapy was given to treat intrathoracic disease in 15 fractions to a total of 50, 55, or 60 Gy. Fifty-five patients were enrolled: 15 at the 50-Gy, 21 at the 55-Gy, and 19 at the 60-Gy dose levels. A 90-day follow-up was completed in each group without exceeding the MTD. With a median follow-up of 12.5 months, there were 93 grade ≥ 3 adverse events (AEs), including 39 deaths, although most AEs were considered related to factors other than radiation therapy. One patient from the 55- and 60-Gy dose groups developed grade ≥ 3 esophagitis, and 5, 4, and 4 patients in the respective dose groups experienced grade ≥ 3 dyspnea, but only 2 of these AEs were considered likely related to therapy. There was no association between fraction size and toxicity (P = .24). The median overall survival was 6 months with no significant differences between dose levels (P = .59). Precision hypofractionated radiation therapy consisting of 60 Gy in 15 fractions for locally advanced NSCLC is generally well tolerated. This treatment regimen could provide patients with poor performance status a potent alternative to chemoradiation. This study has implications for the cost effectiveness of lung cancer therapy. Additional studies of long-term safety and efficacy of this therapy are warranted

  15. Model Performance Evaluation and Scenario Analysis (MPESA)

    Science.gov (United States)

    Model Performance Evaluation and Scenario Analysis (MPESA) assesses the performance with which models predict time series data. The tool was developed Hydrological Simulation Program-Fortran (HSPF) and the Stormwater Management Model (SWMM)

  16. Developing a Parenting Training Model of Character Education for Young Learners from Poor Families by Using Transformative Learning Approach

    Science.gov (United States)

    Rasyad, Ach.

    2015-01-01

    This research is aiming at developing a parenting training model using a character education for young learners from the poor families. The data obtained were qualitative data drawn from open answers and Focus Group Discussion. The data were analyzed by using domain analysis and taxonomy. The research findings showed that there were some problems…

  17. A multi-step pathway connecting short sleep duration to daytime somnolence, reduced attention, and poor academic performance: an exploratory cross-sectional study in teenagers.

    Science.gov (United States)

    Perez-Lloret, Santiago; Videla, Alejandro J; Richaudeau, Alba; Vigo, Daniel; Rossi, Malco; Cardinali, Daniel P; Perez-Chada, Daniel

    2013-05-15

    A multi-step causality pathway connecting short sleep duration to daytime somnolence and sleepiness leading to reduced attention and poor academic performance as the final result can be envisaged. However this hypothesis has never been explored. To explore consecutive correlations between sleep duration, daytime somnolence, attention levels, and academic performance in a sample of school-aged teenagers. We carried out a survey assessing sleep duration and daytime somnolence using the Pediatric Daytime Sleepiness Scale (PDSS). Sleep duration variables included week-days' total sleep time, usual bedtimes, and absolute weekday to-weekend sleep time difference. Attention was assessed by d2 test and by the coding subtest from the WISC-IV scale. Academic performance was obtained from literature and math grades. Structural equation modeling was used to assess the independent relationships between these variables, while controlling for confounding effects of other variables, in one single model. Standardized regression weights (SWR) for relationships between these variables are reported. Study sample included 1,194 teenagers (mean age: 15 years; range: 13-17 y). Sleep duration was inversely associated with daytime somnolence (SWR = -0.36, p academic results (SWR = 0.18, p academic achievements (SWR = -0.16, p sleep duration influenced attention through daytime somnolence (p academic achievements through reduced attention (p academic achievements correlated with reduced attention, which in turn was related to daytime somnolence. Somnolence correlated with short sleep duration.

  18. Modelling the impact of antiretroviral use in resource-poor settings.

    Directory of Open Access Journals (Sweden)

    Rebecca F Baggaley

    2006-04-01

    Full Text Available BACKGROUND: The anticipated scale-up of antiretroviral therapy (ART in high-prevalence, resource-constrained settings requires operational research to guide policy on the design of treatment programmes. Mathematical models can explore the potential impacts of various treatment strategies, including timing of treatment initiation and provision of laboratory monitoring facilities, to complement evidence from pilot programmes. METHODS AND FINDINGS: A deterministic model of HIV transmission incorporating ART and stratifying infection progression into stages was constructed. The impact of ART was evaluated for various scenarios and treatment strategies, with different levels of coverage, patient eligibility, and other parameter values. These strategies included the provision of laboratory facilities that perform CD4 counts and viral load testing, and the timing of the stage of infection at which treatment is initiated. In our analysis, unlimited ART provision initiated at late-stage infection (AIDS increased prevalence of HIV infection. The effect of additionally treating pre-AIDS patients depended on the behaviour change of treated patients. Different coverage levels for ART do not affect benefits such as life-years gained per person-year of treatment and have minimal effect on infections averted when treating AIDS patients only. Scaling up treatment of pre-AIDS patients resulted in more infections being averted per person-year of treatment, but the absolute number of infections averted remained small. As coverage increased in the models, the emergence and risk of spread of drug resistance increased. Withdrawal of failing treatment (clinical resurgence of symptoms, immunologic (CD4 count decline, or virologic failure (viral rebound increased the number of infected individuals who could benefit from ART, but effectiveness per person is compromised. Only withdrawal at a very early stage of treatment failure, soon after viral rebound, would have a

  19. Qualitative and quantitative examination of the performance of regional air quality models representing different modeling approaches

    International Nuclear Information System (INIS)

    Bhumralkar, C.M.; Ludwig, F.L.; Shannon, J.D.; McNaughton, D.

    1985-04-01

    The calculations of three different air quality models were compared with the best available observations. The comparisons were made without calibrating the models to improve agreement with the observations. Model performance was poor for short averaging times (less than 24 hours). Some of the poor performance can be traced to errors in the input meteorological fields, but error exist on all levels. It should be noted that these models were not originally designed for treating short-term episodes. For short-term episodes, much of the variance in the data can arise from small spatial scale features that tend to be averaged out over longer periods. These small spatial scale features cannot be resolved with the coarse grids that are used for the meteorological and emissions inputs. Thus, it is not surprising that the models performed for the longer averaging times. The models compared were RTM-II, ENAMAP-2 and ACID. (17 refs., 5 figs., 4 tabs

  20. Precision Hypofractionated Radiation Therapy in Poor Performing Patients With Non-Small Cell Lung Cancer: Phase 1 Dose Escalation Trial

    Energy Technology Data Exchange (ETDEWEB)

    Westover, Kenneth D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Loo, Billy W. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Gerber, David E. [Division of Hematology-Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Iyengar, Puneeth; Choy, Hak [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Diehn, Maximilian [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Hughes, Randy; Schiller, Joan; Dowell, Jonathan [Division of Hematology-Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wardak, Zabi [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Sher, David [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States); Christie, Alana; Xie, Xian-Jin [Department of Clinical Science, Southwestern Medical Center, Dallas, Texas (United States); Corona, Irma [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Sharma, Akanksha [School of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wadsworth, Margaret E. [Radiation Oncology of Mississippi, Jackson, Mississippi (United States); Timmerman, Robert, E-mail: Robert.Timmerman@utsouthwestern.edu [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2015-09-01

    Purpose: Treatment regimens for locally advanced non-small cell lung cancer (NSCLC) give suboptimal clinical outcomes. Technological advancements such as radiation therapy, the backbone of most treatment regimens, may enable more potent and effective therapies. The objective of this study was to escalate radiation therapy to a tumoricidal hypofractionated dose without exceeding the maximally tolerated dose (MTD) in patients with locally advanced NSCLC. Methods and Materials: Patients with stage II to IV or recurrent NSCLC and Eastern Cooperative Oncology Group performance status of 2 or greater and not candidates for surgical resection, stereotactic radiation, or concurrent chemoradiation were eligible. Highly conformal radiation therapy was given to treat intrathoracic disease in 15 fractions to a total of 50, 55, or 60 Gy. Results: Fifty-five patients were enrolled: 15 at the 50-Gy, 21 at the 55-Gy, and 19 at the 60-Gy dose levels. A 90-day follow-up was completed in each group without exceeding the MTD. With a median follow-up of 12.5 months, there were 93 grade ≥3 adverse events (AEs), including 39 deaths, although most AEs were considered related to factors other than radiation therapy. One patient from the 55- and 60-Gy dose groups developed grade ≥3 esophagitis, and 5, 4, and 4 patients in the respective dose groups experienced grade ≥3 dyspnea, but only 2 of these AEs were considered likely related to therapy. There was no association between fraction size and toxicity (P=.24). The median overall survival was 6 months with no significant differences between dose levels (P=.59). Conclusions: Precision hypofractionated radiation therapy consisting of 60 Gy in 15 fractions for locally advanced NSCLC is generally well tolerated. This treatment regimen could provide patients with poor performance status a potent alternative to chemoradiation. This study has implications for the cost effectiveness of lung cancer therapy. Additional studies of long

  1. Visual search performance in children rated as good or poor attenders: the differential impact of DAT1 genotype, IQ, and chronological age.

    Science.gov (United States)

    Cornish, K M; Wilding, J M; Hollis, C

    2008-03-01

    Attention-deficit/hyperactivity disorder (ADHD) is characterized by poor attention to detail, poor attention maintenance, and variability throughout task performance. The authors used a quantitative trait loci approach to assess the association between the dopamine transporter (DAT1) high-risk genotype, cognitive performance (visual search and vigilance), and ADHD symptoms in a community sample of boys 6-11 years of age. The potential confounding effects of IQ and chronological age were also investigated. Results demonstrate that accuracy in target detection, not speed, distinguishes poor attenders from good attenders. The authors speculate that the measure of performance (e.g., time and false alarms) may be critical in detecting attentional weaknesses. In contrast, DAT1 gene, known to be associated with the behavioral symptoms of ADHD, was unrelated to visual search or vigilance performance, although it was related to ADHD symptoms.

  2. Alkyl polyglucoside vs. ethoxylated surfactant-based microemulsions as vehicles for two poorly water-soluble drugs: physicochemical characterization and in vivo skin performance

    Directory of Open Access Journals (Sweden)

    Pajić Nataša Z. Bubić

    2017-12-01

    Full Text Available Two types of biocompatible surfactants were evaluated for their capability to formulate skin-friendly/non-irritant microemulsions as vehicles for two poorly water-soluble model drugs differing in properties and concentrations: alkyl polyglucosides (decyl glucoside and caprylyl/capryl glucoside and ethoxylated surfactants (glycereth-7-caprylate/ caprate and polysorbate 80. Phase behavior, structural inversion and microemulsion solubilization potential for sertaconazole nitrate and adapalene were found to be highly dependent on the surfactants structure and HLB value. Performed characterization (polarized light microscopy, pH, electrical conductivity, rheological, FTIR and DSC measurements indicated a formulation containing glycereth- 7-caprylate/caprate as suitable for incorporation of both drugs, whereas alkyl polyglucoside-based systems did not exhibit satisfying solubilization capacity for sertaconazole nitrate. Further, monitored parameters were strongly affected by sertaconazole nitrate incorporation, while they remained almost unchanged in adapalene-loaded vehicles. In addition, results of the in vivo skin performance study supported acceptable tolerability for all investigated formulations, suggesting selected microemulsions as promising carriers worth exploring further for effective skin delivery of model drugs.

  3. Our calibrated model has poor predictive value: An example from the petroleum industry

    International Nuclear Information System (INIS)

    Carter, J.N.; Ballester, P.J.; Tavassoli, Z.; King, P.R.

    2006-01-01

    It is often assumed that once a model has been calibrated to measurements then it will have some level of predictive capability, although this may be limited. If the model does not have predictive capability then the assumption is that the model needs to be improved in some way. Using an example from the petroleum industry, we show that cases can exit where calibrated models have limited predictive capability. This occurs even when there is no modelling error present. It is also shown that the introduction of a small modelling error can make it impossible to obtain any models with useful predictive capability. We have been unable to find ways of identifying which calibrated models will have some predictive capacity and those which will not

  4. Why are decisions in flood disaster management so poorly supported by information from flood models?

    NARCIS (Netherlands)

    Leskens, Anne; Brugnach, Marcela Fabiana; Hoekstra, Arjen Ysbert; Schuurmans, W.

    2014-01-01

    Flood simulation models can provide practitioners of Flood Disaster Management with sophisticated estimates of floods. Despite the advantages that flood simulation modeling may provide, experiences have proven that these models are of limited use. Until now, this problem has mainly been investigated

  5. Calibration of PMIS pavement performance prediction models.

    Science.gov (United States)

    2012-02-01

    Improve the accuracy of TxDOTs existing pavement performance prediction models through calibrating these models using actual field data obtained from the Pavement Management Information System (PMIS). : Ensure logical performance superiority patte...

  6. Poor performance of serological tests in the diagnosis of pulmonary tuberculosis: evidence from a contact tracing field study.

    Directory of Open Access Journals (Sweden)

    Sarman Singh

    Full Text Available BACKGROUND: Delayed or missed diagnosis of TB continues to fuel the global TB epidemic, especially in resource limited settings. Use of serology for the diagnosis of tuberculosis, commonly used in India, is another factor. In the present study a commercially available serodiagnostic assay was assessed for its diagnostic value in combination with smear, culture and clinical manifestations. METHODOLOGY/PRINCIPAL FINDINGS: A total of 2300 subjects were recruited for the study, but 1041 subjects were excluded for various reasons. Thus 1259 subjects were included in the study of which 470 were pulmonary tuberculosis cases (440 of 470 were culture-positive and 789 were their asymptomatic contacts. A house-to-house survey method was used. Blood samples were tested for IgM, IgA, and IgG antibodies using the Pathozyme Myco M (IgM, Myco A (IgA and Myco G (IgG enzyme immunoassay (EIA. Out of 470 PTB cases, BCG scar was positive in 82.34%. The Mantoux test and smear positivity rates in PTB cases were 94.3% (430/456, and 65.32% (307/470, respectively. Among the asymptomatic contacts, BCG scar was positive in 95.3% and Mantoux test was positive in 80.66% (442/548 contacts. No contact was found falsely smear positive. The sensitivity of IgM, IgA, and IgG EIA tests was 48.7%, 25.7% and 24.4%, respectively, while the specificity was 71.5%, 80.5%, 76.6%, respectively. Performance of EIAs was not affected by the previous BCG vaccination. However, prior BCG vaccination was statistically significantly (p = 0.005 associated with Mantoux test positivity in PTB cases but not in contacts (p = 0.127. The agreement between serology and Mantoux test was not significant. CONCLUSION: The commercial serological test evaluated showed poor sensitivity and specificity and suggests no utility for detection of pulmonary tuberculosis.

  7. Liberal versus neo-developmental convention to growth: why has Brazil shown a poor performance since the 1980s?

    Directory of Open Access Journals (Sweden)

    André Nassif

    2013-12-01

    Full Text Available The main goal of our paper is to provide analytical arguments to explain why Brazil has not been able to restore its long-term capacity for economic growth, especially compared with its economy in the 1950-1979 period (7.3 per cent per year on average or even with a select number of emerging economies in the 1980-2010 period(6.7 per cent per year on average, against 2.3 per cent per year on average in Brazil in the same period. We build our idea of convention to growth based on the Keynesian concept of convention. For our purposes, this concept could be briefly summarized as the way in which the set of public and private economic decisions related to different objectives, such as how much to produce and invest, how much to charge for products and services, how to finance public and private debt, how to finance research and development, and so on, are indefinitely - or at least until there is no change- carried out by the political, economic and social institutions. This analytical reference can be connected to the Neo-Schumpeterian National Innovation System (NIS concept, which emphasizes not only institutions associated with science and technology per se, but also the complex interaction among them and other institutions. In this paper we identify two conventions to long-term growth in the last three decades in Brazil: the liberal and the neo-developmental. We show that the poor performance in the Brazilian economy in terms of real GDP growth from the 1980s on can be explained by a weak coordination between short-term macroeconomic policies and long-term industrial and technological policies. This weak coordination, in turn, can be associated with the prevalence of the liberal convention from the 1990s on, which has emphasized price stabilization to the detriment of a neo-developmental strategy whose primary goal is to sustain higher rates of growth and full employment in Brazil.

  8. Metabolic syndrome correlates poorly with cognitive performance in stroke-free community-dwelling older adults: a population-based, cross-sectional study in rural Ecuador.

    Science.gov (United States)

    Del Brutto, Oscar H; Mera, Robertino M; Zambrano, Mauricio

    2016-04-01

    Studies investigating a possible correlation between metabolic syndrome and cognitive decline have been inconsistent. To determine whether metabolic syndrome or each of its components correlate with cognitive performance in community-dwelling older adults in rural Ecuador. Stroke-free Atahualpa residents aged ≥60 years were identified during a door-to-door survey. Metabolic syndrome was defined according to the International Diabetes Federation criteria. Cognition was evaluated by the use of the Montreal Cognitive Assessment (MoCA). Multivariate logistic regression models estimated the association between metabolic syndrome and each of its components with cognitive performance. A total of 212 persons (mean age: 69.2 ± 7.2 years, 64 % women) were enrolled. Of these, 120 (57 %) had metabolic syndrome. Mean scores in the MoCA were 18.2 ± 4.6 for persons with and 19 ± 4.7 for those without metabolic syndrome. In fully adjusted logistic models, MoCA scores were not associated with metabolic syndrome (p = 0.101). After testing individual components of metabolic syndrome with the MoCA score, we found that only hypertriglyceridemia was independently associated with the MoCA score (p = 0.009). This population-based study showed a poor correlation of metabolic syndrome with cognitive performance after adjusting for relevant confounders. Of the individual components of metabolic syndrome, only hypertriglyceridemia correlated with worse cognitive performance.

  9. Performance comparison of hydrological model structures during low flows

    Science.gov (United States)

    Staudinger, Maria; Stahl, Kerstin; Tallaksen, Lena M.; Clark, Martyn P.; Seibert, Jan

    2010-05-01

    Low flows are still poorly reproduced by common hydrological models since they are traditionally designed to meet peak flow situations best possible. As low flow becomes increasingly important to several target areas there is a need to improve available models. We present a study that assesses the impact of model structure on low flow simulations. This is done using the Framework for Understanding Structural Errors (FUSE), which identifies the set of (subjective) decisions made when building a hydrological model, and provides multiple options for each modeling decision. 79 models were built using the FUSE framework, and applied to simulate stream flows in the Narsjø catchment in Norway (119 km²). To allow comparison all new models were calibrated using an automatic optimization method. Low flow and recession analysis of the new models enables us to evaluate model performance focusing on different aspects by using various objective functions. Additionally, model structures responsible for poor performance, and hence unsuitable, can be detected. We focused on elucidating model performance during summer (August - October) and winter low flows which evolve from entirely different hydrological processes in the Narsjø catchment. Summer low flows develop out of a lack of precipitation while winter low flows are due to water storage in ice and snow. The results showed that simulations of summer low flows were throughout poorer than simulations of winter low flows when evaluating with an objective function focusing on low flows; here, the model structure influencing winter low flow simulations is the lower layer architecture. Different model structures were found to influence model performance during the summer season. The choice of other objective functions has the potential to affect such an evaluation. These findings call for the use of different model structures tailored to particular needs.

  10. Multiple choice questions are superior to extended matching questions to identify medicine and biomedical sciences students who perform poorly.

    Science.gov (United States)

    Eijsvogels, Thijs M H; van den Brand, Tessa L; Hopman, Maria T E

    2013-11-01

    In recent years, medical faculties at Dutch universities have implemented a legally binding study advice to students of medicine and biomedical sciences during their propaedeutic phase. Appropriate examination is essential to discriminate between poor (grade age and examination preference on this score. Data were collected for 452 first-year medical and biomedical science students during three distinct course examinations: one examination with EMQ only, one with MCQ only and one mixed examination (including EMQ and MCQ). Logistic regression analysis revealed that MCQ examination was 3 times better in identifying poor students compared with EMQ (RR 3.0, CI 2.0-4.5), whereas EMQ better detected excellent students (average grade ≥8) (RR 1.93, CI 1.47-2.53). Mixed examination had comparable characteristics to MCQ. Sex and examination preference did not impact the score of the student. Students ≥20 years had a 4-fold higher risk ratio of obtaining a poor grade (<6) compared with students ≤18 years old (RR 4.1, CI 2.1-8.0). Given the strong discriminative capacity of MCQ examinations to identify poor students, we recommend the use of this type of examination during the propaedeutic phase of medicine and biomedical science study programmes, in the light of the binding study advice.

  11. Multiple choice questions are superior to extended matching questions to identify medicine and biomedical sciences students who perform poorly.

    NARCIS (Netherlands)

    Eijsvogels, T.M.H.; Brand, T.L. van den; Hopman, M.T.E.

    2013-01-01

    In recent years, medical faculties at Dutch universities have implemented a legally binding study advice to students of medicine and biomedical sciences during their propaedeutic phase. Appropriate examination is essential to discriminate between poor (grade <6), moderate (grade 6-8) and excellent

  12. A Risk Prediction Model Based on Lymph-Node Metastasis in Poorly Differentiated-Type Intramucosal Gastric Cancer.

    Directory of Open Access Journals (Sweden)

    Jeung Hui Pyo

    Full Text Available Endoscopic submucosal dissection (ESD for undifferentiated type early gastric cancer is regarded as an investigational treatment. Few studies have tried to identify the risk factors that predict lymph-node metastasis (LNM in intramucosal poorly differentiated adenocarcinomas (PDC. This study was designed to develop a risk scoring system (RSS for predicting LNM in intramucosal PDC.From January 2002 to July 2015, patients diagnosed with mucosa-confined PDC, among those who underwent curative gastrectomy with lymph node dissection were reviewed. A risk model based on independent predicting factors of LNM was developed, and its performance was internally validated using a split sample approach.Overall, LNM was observed in 5.2% (61 of 1169 patients. Four risk factors [Female sex, tumor size ≥ 3.2 cm, muscularis mucosa (M3 invasion, and lymphatic-vascular involvement] were significantly associated with LNM, which were incorporated into the RSS. The area under the receiver operating characteristic curve for predicting LNM after internal validation was 0.69 [95% confidence interval (CI, 0.59-0.79]. A total score of 2 points corresponded to the optimal RSS threshold with a discrimination of 0.75 (95% CI 0.69-0.81. The LNM rates were 1.6% for low risk (<2 points and 8.9% for high-risk (≥2 points patients, with a negative predictive value of 98.6% (95% CI 0.98-1.00.A RSS could be useful in clinical practice to determine which patients with intramucosal PDC have low risk of LNM.

  13. How Can Childbirth Care for the Rural Poor Be Improved? A Contribution from Spatial Modelling in Rural Tanzania.

    Directory of Open Access Journals (Sweden)

    Piera Fogliati

    Full Text Available Maternal and perinatal mortality remain a challenge in resource-limited countries, particularly among the rural poor. To save lives at birth health facility delivery is recommended. However, increasing coverage of institutional deliveries may not translate into mortality reduction if shortage of qualified staff and lack of enabling working conditions affect quality of services. In Tanzania childbirth care is available in all facilities; yet maternal and newborn mortality are high. The study aimed to assess in a high facility density rural context whether a health system organization with fewer delivery sites is feasible in terms of population access.Data on health facilities' location, staffing and delivery caseload were examined in Ludewa and Iringa Districts, Southern Tanzania. Geospatial raster and network analysis were performed to estimate access to obstetric services in walking time. The present geographical accessibility was compared to a theoretical scenario with a 40% reduction of delivery sites.About half of first-line health facilities had insufficient staff to offer full-time obstetric services (45.7% in Iringa and 78.8% in Ludewa District. Yearly delivery caseload at first-line health facilities was low, with less than 100 deliveries in 48/70 and 43/52 facilities in Iringa and Ludewa District respectively. Wide geographical overlaps of facility catchment areas were observed. In Iringa 54% of the population was within 1-hour walking distance from the nearest facility and 87.8% within 2 hours, in Ludewa, the percentages were 39.9% and 82.3%. With a 40% reduction of delivery sites, approximately 80% of population will still be within 2 hours' walking time.Our findings from spatial modelling in a high facility density context indicate that reducing delivery sites by 40% will decrease population access within 2 hours by 7%. Focused efforts on fewer delivery sites might assist strengthening delivery services in resource-limited settings.

  14. Poor trail making test performance is directly associated with altered dual task prioritization in the elderly--baseline results from the TREND study.

    Science.gov (United States)

    Hobert, Markus A; Niebler, Raphael; Meyer, Sinja I; Brockmann, Kathrin; Becker, Clemens; Huber, Heiko; Gaenslen, Alexandra; Godau, Jana; Eschweiler, Gerhard W; Berg, Daniela; Maetzler, Walter

    2011-01-01

    Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance--which specifically measures cognitive flexibility and working memory--and dual task costs, a measure of prioritization. Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders), 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A). The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range -6 to 58%) compared to the good performers (17%; -16 to 43%; pelderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive flexibility and working memory are directly associated with altered prioritization.

  15. Why is Africa so poor? A structural model of economic development and income inequality.

    OpenAIRE

    David Fielding

    2001-01-01

    The paper extends existing work on inequality and economic development by estimating a cross-country structural model that identifies bi-directional relationships between income inequality and other indicators of social and economic development. Overall, lower inequality is associated with improvements in other development indicators, but this is the result of several complex interactions. The most striking feature of the structural model is the insight it provides into the reasons behind the...

  16. A model of poorly controlled type 1 Diabetes Mellitus and its treatment with aerobic exercise training.

    Science.gov (United States)

    Melling, C W J; Grisé, K N; Hasilo, C P; Fier, B; Milne, K J; Karmazyn, M; Noble, E G

    2013-05-01

    Modern exogenous insulin therapy can improve the quality of life of Type 1 Diabetic Mellitus (T1DM) patients, although maintenance of normal glycaemic levels is often a challenge given the variety of factors that alter it. A number of studies have examined the effect of exercise in T1DM; however, the majority of experimental studies have utilized diabetic rodents with severe hyperglycaemia. Given that T1DM patients are likely to refrain from hyperglycaemia, studies examining the effects of regular exercise in which blood glucose is poorly controlled would better represent the T1DM population. The current study examined the ability of a ten-week aerobic exercise training program to modify markers of cardiovascular function and bone health in STZ-induced diabetic rodents maintained in the 9-15 mM glycaemic range through insulin therapy. Moderate hyperglycaemia, when prolonged, leads to significant changes in cardiac structure, bone health, and glucose handling capacity. Ten weeks of exercise was able to alleviate many of these deleterious events as no significant cardiovascular functional alterations were evident except a reduction in resting heart rate and an increase in stroke volume index. Further, despite changes in cardiac dimensions, exercise was able to elevate cardiac output index and increase the E/A ratio of exercising diabetic animals which would be indicative of improvements of cardiac function. Together, this study demonstrates that despite moderate hyperglycaemia, the combined role of a ten-week exercise training program coupled with insulin therapy is able to alleviate many of the well-known complications associated with diabetes progression. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  17. Metal-rich, Metal-poor: Updated Stellar Population Models for Old Stellar Systems

    Science.gov (United States)

    Conroy, Charlie; Villaume, Alexa; van Dokkum, Pieter G.; Lind, Karin

    2018-02-01

    We present updated stellar population models appropriate for old ages (>1 Gyr) and covering a wide range in metallicities (‑1.5 ≲ [Fe/H] ≲ 0.3). These models predict the full spectral variation associated with individual element abundance variation as a function of metallicity and age. The models span the optical–NIR wavelength range (0.37–2.4 μm), include a range of initial mass functions, and contain the flexibility to vary 18 individual elements including C, N, O, Mg, Si, Ca, Ti, and Fe. To test the fidelity of the models, we fit them to integrated light optical spectra of 41 Galactic globular clusters (GCs). The value of testing models against GCs is that their ages, metallicities, and detailed abundance patterns have been derived from the Hertzsprung–Russell diagram in combination with high-resolution spectroscopy of individual stars. We determine stellar population parameters from fits to all wavelengths simultaneously (“full spectrum fitting”), and demonstrate explicitly with mock tests that this approach produces smaller uncertainties at fixed signal-to-noise ratio than fitting a standard set of 14 line indices. Comparison of our integrated-light results to literature values reveals good agreement in metallicity, [Fe/H]. When restricting to GCs without prominent blue horizontal branch populations, we also find good agreement with literature values for ages, [Mg/Fe], [Si/Fe], and [Ti/Fe].

  18. Human Performance Models of Pilot Behavior

    Science.gov (United States)

    Foyle, David C.; Hooey, Becky L.; Byrne, Michael D.; Deutsch, Stephen; Lebiere, Christian; Leiden, Ken; Wickens, Christopher D.; Corker, Kevin M.

    2005-01-01

    Five modeling teams from industry and academia were chosen by the NASA Aviation Safety and Security Program to develop human performance models (HPM) of pilots performing taxi operations and runway instrument approaches with and without advanced displays. One representative from each team will serve as a panelist to discuss their team s model architecture, augmentations and advancements to HPMs, and aviation-safety related lessons learned. Panelists will discuss how modeling results are influenced by a model s architecture and structure, the role of the external environment, specific modeling advances and future directions and challenges for human performance modeling in aviation.

  19. Reaching Urban Poor Hypertensive Patients: A Novel Model of Chronic Disease Care Versus a Traditional Fee-for-Service Approach.

    Science.gov (United States)

    Sanders, Jim; Guse, Clare E

    2016-08-09

    There is a significant disparity in hypertensive treatment rates between those with and without health insurance. If left untreated, hypertension leads to significant morbidity and mortality. The uninsured face numerous barriers to access chronic disease care. We developed the Community-based Chronic Disease Management (CCDM) clinics specifically for the uninsured with hypertension utilizing nurse-led teams, community-based locations, and evidence-based clinical protocols. All services, including laboratory and medications, are provided on-site and free of charge. In order to ascertain if the CCDM model of care was as effective as traditional models of care in achieving blood pressure goals, we compared CCDM clinics' hypertensive care outcomes with 2 traditional fee-for-service physician-led clinics. All the clinics are located near one another in poor urban neighborhoods of Milwaukee, Wisconsin. Patients seen at the CCDM clinics and at 1 of the 2 traditional clinics showed a statistically significant improvement in reaching blood pressure goal at 6 months (P service clinics when compared with the CCDM clinics. The CCDM model of care is at least as effective in controlling hypertension as more traditional fee-for-service models caring for the same population. The CCDM model of care to treat hypertension may offer another approach for engaging the urban poor in chronic disease care. © The Author(s) 2016.

  20. Modeling the burden of poultry disease on the rural poor in Madagascar

    Directory of Open Access Journals (Sweden)

    Cassidy L. Rist

    2015-12-01

    Full Text Available Livestock represent a fundamental economic and nutritional resource for many households in the developing world; however, a high burden of infectious disease limits their production potential. Here we present an ecological framework for estimating the burden of poultry disease based on coupled models of infectious disease and economics. The framework is novel, as it values humans and livestock as co-contributors to household wellbeing, incorporating feedbacks between poultry production and human capital in disease burden estimates. We parameterize this coupled ecological–economic model with household-level data to provide an estimate of the overall burden of poultry disease for the Ifanadiana District in Madagascar, where over 72% of households rely on poultry for economic and food security. Our models indicate that households may lose 10–25% of their monthly income under current disease conditions. Results suggest that advancements in poultry health may serve to support income generation through improvements in both human and animal health.

  1. The negative effects of obesity and poor glycemic control on cognitive function: a proposed model for possible mechanisms.

    Science.gov (United States)

    Alosco, Michael L; Gunstad, John

    2014-06-01

    Obesity has reached epidemic proportions and is a contributor to many adverse health outcomes, including increased risk for dementia and adverse structural and functional brain changes. Milder forms of cognitive impairment in multiple domains can also be found in obese individuals of all ages that are believed to stem from brain abnormalities long prior to onset of neurologic conditions such as dementia. However, the mechanisms for adverse brain changes and subsequent cognitive dysfunction in obesity are complex and poorly understood. This paper proposes a possible etiologic model for obesity associated cognitive impairment with emphasis on the role of poor glycemic control and conditions like type 2 diabetes mellitus. Clinical implications associated with treatment of obesity in persons with cognitive deficits in addition to the cognitive promoting effects of weight loss surgery are also discussed.

  2. An Innovative Model of Management Education for the Poor: The South African Experience

    Science.gov (United States)

    Heaton, Dennis P.

    2008-01-01

    Community and Individual Development Association (CIDA) City Campus is a private business college that provides bachelor's degrees to economically disadvantaged students in South Africa. CIDA's model of management education is in stark contrast to conventional business schools, which are not accessible to or adapted to students from extreme…

  3. Modelling and Motivating Academic Performance.

    Science.gov (United States)

    Brennan, Geoffrey; Pettit, Philip

    1991-01-01

    Three possible motivators for college teachers (individual economic interest, academic virtue, and academic honor) suggest mechanisms that can be used to improve performance. Policies need to address all three motivators; economic levers alone may undermine alternative ways of supporting good work. (MSE)

  4. Perception of Students on Causes of Poor Performance in Chemistry in External Examinations in Umuahia North Local Government of Abia State

    Science.gov (United States)

    Ojukwu, M. O.

    2016-01-01

    The aim of this study was to investigate the perception of students on the causes of their poor performance in external chemistry examinations in Umuahia North Local Government Area of Abia State. Descriptive survey design was used for the study. Two hundred and forty (240) students were selected through simple random sampling for the study. A…

  5. Nasogastric tube-administered alectinib achieved long-term survival in a crizotinib-refractory nonsmall cell lung cancer patient with a poor performance status.

    Science.gov (United States)

    Kanai, Osamu; Kim, Young Hak; Nakatani, Koichi; Fujita, Kohei; Mio, Tadashi

    2017-06-01

    Alectinib shows remarkable efficacy against anaplastic lymphoma kinase (ALK)-positive nonsmall cell lung cancer (NSCLC), with minimal adverse effects. Therefore, alectinib may provide a survival benefit to ALK-positive NSCLC patients with a poor performance status. If the medication cannot be taken by mouth, the patient may be given alectinib through a nasogastric tube.

  6. Not self-focused attention but negative beliefs affect poor social performance in social anxiety : An investigation of pathways in the social anxiety-social rejection relationship

    NARCIS (Netherlands)

    Voncken, Marisol J.; Dijk, Corine; de Jong, Peter J.; Roelofs, Jeffrey

    2010-01-01

    Patients with social anxiety disorder (SAD) not only fear negative evaluation but are indeed less likeable than people without SAD. Previous research shows social performance to mediate this social anxiety-social rejection relationship. This study studied two pathways hypothesized to lead to poor

  7. Not self-focused attention but negative beliefs affect poor social performance in social anxiety: an investigation of pathways in the social anxiety - social rejection relationship

    NARCIS (Netherlands)

    Voncken, M.J.; Dijk, C.; de Jong, P.J.; Roelofs, J.

    2010-01-01

    Patients with social anxiety disorder (SAD) not only fear negative evaluation but are indeed less likeable than people without SAD. Previous research shows social performance to mediate this social anxiety-social rejection relationship. This study studied two pathways hypothesized to lead to poor

  8. Transformative Learning Model for Youth Life Skills Entrepreneurs in Poor Weavers Songket Palembang

    Directory of Open Access Journals (Sweden)

    Ayi Olim

    2015-05-01

    Full Text Available Non-formal education serves to develop the potential of students with an emphasis on the mastery of knowledge and functional skills and professional attitude and personality development, is now understood as an alternative approach to the future education with an emphasis on the mastery of skills. transformative learning, life skills and entrepreneurship as a modality of model development. learner/ prospective participants learn from the lower-middle group (in the shadow of the transmission of learning should be the owner of the learning process and should be able to identify the capabilities and environmental problems, reflect and take action in developing entrepreneurial abilities. The model requires changing patterns of transformative learning and utilization participants life skills learning, facilitation and management support from stakeholders

  9. Blunt cerebrovascular injury is poorly predicted by modeling with other injuries: analysis of NTDB data.

    Science.gov (United States)

    Cook, Alan; Osler, Turner; Gaudet, Matthew; Berne, John; Norwood, Scott

    2011-07-01

    Traumatic blunt cerebrovascular injury (BCVI) may portend catastrophic complications if untreated. Who should be screened for BCVI is controversial. The purpose of this study was to develop and validate a prediction score (pBCVI) to identify those at sufficient risk to warrant dedicated screening. We conducted a cohort study using data for years 2002-2007 from the National Trauma Data Bank. Blunt trauma patients aged 16 years and older were randomly divided into two groups for score creation and validation. Final prediction model included age, sex, Trauma Mortality Prediction Model p(death), traumatic intracranial hemorrhage, cerebellar/brain stem injury, malar/maxillary fracture, mandible fracture, cervical spine fracture, cervical spinal cord injury, thoracic spinal cord injury, and chest Abbreviated Injury Scale ≥3. pBCVI was evaluated using receiver operating characteristic curve area and the Hosmer-Lemeshow statistic. The Youden Index estimated an optimal cut-point (J) of the pBCVI. The cohort numbered 1,398,310 patients, including 2,125 with BCVI. The overall incidence of BCVI was 0.15%. Cervical spine fracture had the strongest association with BCVI (odds ratio 4.82, p < 0.001). The receiver operating characteristic curve for pBCVI was 0.93 and the Hosmer-Lemeshow statistic was 206.3, p < 0.01. The optimal cut-point (J) of pBCVI was 0.0013 (sensitivity 0.91, specificity 0.82) and would miss 186 (8.8%) injuries in our cohort. To identify all BCVI using this model, an unrealistic 96% of the cohort would require screening. A model based on a pattern of other injuries cannot be used as a stand-alone instrument to determine screening for BCVI. "Optimal" model cut-points are not ideal for all injuries. Clinical suspicion that integrates energy of mechanism and associated injuries remains essential to effectively screen for BCVI and minimize patient risk for a catastrophic missed injury.

  10. Cognitive performance modeling based on general systems performance theory.

    Science.gov (United States)

    Kondraske, George V

    2010-01-01

    General Systems Performance Theory (GSPT) was initially motivated by problems associated with quantifying different aspects of human performance. It has proved to be invaluable for measurement development and understanding quantitative relationships between human subsystem capacities and performance in complex tasks. It is now desired to bring focus to the application of GSPT to modeling of cognitive system performance. Previous studies involving two complex tasks (i.e., driving and performing laparoscopic surgery) and incorporating measures that are clearly related to cognitive performance (information processing speed and short-term memory capacity) were revisited. A GSPT-derived method of task analysis and performance prediction termed Nonlinear Causal Resource Analysis (NCRA) was employed to determine the demand on basic cognitive performance resources required to support different levels of complex task performance. This approach is presented as a means to determine a cognitive workload profile and the subsequent computation of a single number measure of cognitive workload (CW). Computation of CW may be a viable alternative to measuring it. Various possible "more basic" performance resources that contribute to cognitive system performance are discussed. It is concluded from this preliminary exploration that a GSPT-based approach can contribute to defining cognitive performance models that are useful for both individual subjects and specific groups (e.g., military pilots).

  11. Toronto area ozone: Long-term measurements and modeled sources of poor air quality events

    Science.gov (United States)

    Whaley, C. H.; Strong, K.; Jones, D. B. A.; Walker, T. W.; Jiang, Z.; Henze, D. K.; Cooke, M. A.; McLinden, C. A.; Mittermeier, R. L.; Pommier, M.; Fogal, P. F.

    2015-11-01

    The University of Toronto Atmospheric Observatory and Environment Canada's Centre for Atmospheric Research Experiments each has over a decade of ground-based Fourier transform infrared (FTIR) spectroscopy measurements in southern Ontario. We present the Toronto area FTIR time series from 2002 to 2013 of two tropospheric trace gases—ozone and carbon monoxide—along with surface in situ measurements taken by government monitoring programs. We interpret their variability with the GEOS-Chem chemical transport model and determine the atmospheric conditions that cause pollution events in the time series. Our analysis includes a regionally tagged O3 model of the 2004-2007 time period, which quantifies the geographical contributions to Toronto area O3. The important emission types for 15 pollution events are then determined with a high-resolution adjoint model. Toronto O3, during pollution events, is most sensitive to southern Ontario and U.S. fossil fuel NOx emissions and natural isoprene emissions. The sources of Toronto pollution events are found to be highly variable, and this is demonstrated in four case studies representing local, short-, middle-, and long-range transport scenarios. This suggests that continental-scale emission reductions could improve air quality in the Toronto region. We also find that abnormally high temperatures and high-pressure systems are common to all pollution events studied, suggesting that climate change may impact Toronto O3. Finally, we quantitatively compare the sensitivity of the surface and column measurements to anthropogenic NOx emissions and show that they are remarkably similar. This work thus demonstrates the usefulness of FTIR measurements in an urban area to assess air quality.

  12. Poor performance status, urban residence and female sex predict inferior survival in pediatric advanced stage mature B-NHL in an Indian tertiary care center.

    Science.gov (United States)

    Patel, Amol; Sharma, Meher Chand; Mallick, Saumyaranjan; Patel, Manali; Bakhshi, Sameer

    2018-02-01

    Advanced stage is a known prognostic factor in B-Non-Hodgkin Lymphoma (NHL); however, factors within advanced stage and overall data on pediatric B-NHL from India are lacking. This is a retrospective study wherein all consecutive pediatric (≤18 years) patients of advanced stage B-NHL (St. Jude stage 3 and 4) treated at our center from Jan 2003 to June 2016 with BFM-90 protocol were evaluated for outcome and pathology review. Total 140 patients were analyzed with median age 8 years; M:F ratio was 5.2:1; 36% patients presented within 30 days of symptom onset and 58% had rural residence. Burkitt lymphoma (66%) was commonest histopathological subtype; bone marrow was involved in 15% and CSF in 8% cases. Undernourishment was observed in 30% patients and 51% had ECOG performance status of 3&4. At 5 years, EFS was 52 ± 4% (CI 0.43-0.60) and OS was 61 ± 4% (CI 0.52-0.68). On multivariate analysis, poor performance status (p residence (p = 0.016) emerged as significant negative prognostic factors for EFS; while for OS, female sex (p = 0.006), poor performance status (p residence (p = 0.023) predicted inferior outcome. This is the largest study from south Asia on advanced stage pediatric B-NHL and it suggests undernourishment, poor performance status and gender bias to be unique features at presentation. Although, outcomes are comparable with other data from resource-challenged nations, yet they are 15-20% inferior than trial data from other developed countries. Further, poor performance status, female sex and urban residence for poor outcome were identified as unique prognostic factors.

  13. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Science.gov (United States)

    2010-04-01

    ... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR PERFORMANCE ACCOUNTABILITY UNDER TITLE I OF THE WORKFORCE... performance agreed to under § 666.310 for the core indicators of performance or customer satisfaction... or customer satisfaction indicators for a program for two consecutive program years, the Governor...

  14. Assembly line performance and modeling

    Science.gov (United States)

    Rane, Arun B.; Sunnapwar, Vivek K.

    2017-09-01

    Automobile sector forms the backbone of manufacturing sector. Vehicle assembly line is important section in automobile plant where repetitive tasks are performed one after another at different workstations. In this thesis, a methodology is proposed to reduce cycle time and time loss due to important factors like equipment failure, shortage of inventory, absenteeism, set-up, material handling, rejection and fatigue to improve output within given cost constraints. Various relationships between these factors, corresponding cost and output are established by scientific approach. This methodology is validated in three different vehicle assembly plants. Proposed methodology may help practitioners to optimize the assembly line using lean techniques.

  15. Floating solid cellulose nanofibre nanofoams for sustained release of the poorly soluble model drug furosemide

    DEFF Research Database (Denmark)

    Svagan, Anna Justina; Müllertz, Anette; Löbmann, Korbinian

    2017-01-01

    OBJECTIVES: This study aimed to prepare a furosemide-loaded sustained release cellulose nanofibre (CNF)-based nanofoams with buoyancy. METHODS: Dry foams consisting of CNF and the model drug furosemide at concentrations of 21% and 50% (w/w) have been prepared by simply foaming a CNF-drug suspension...... followed by drying. The resulting foams were characterized towards their morphology, solid state properties and dissolution kinetics. KEY FINDINGS: Solid state analysis of the resulting drug-loaded foams revealed that the drug was present as an amorphous sodium furosemide salt and in form of furosemide...... form I crystals embedded in the CNF foam cell walls. The foams could easily be shaped and were flexible, and during the drug release study, the foam pieces remained intact and were floating on the surface due to their positive buoyancy. Both foams showed a sustained furosemide release compared...

  16. Modeling determinants of medication attitudes and poor adherence in early nonaffective psychosis: implications for intervention.

    Science.gov (United States)

    Drake, Richard J; Nordentoft, Merete; Haddock, Gillian; Arango, Celso; Fleischhacker, W Wolfgang; Glenthøj, Birte; Leboyer, Marion; Leucht, Stefan; Leweke, Markus; McGuire, Phillip; Meyer-Lindenberg, Andreas; Rujescu, Dan; Sommer, Iris E; Kahn, René S; Lewis, Shon W

    2015-05-01

    We aimed to design a multimodal intervention to improve adherence following first episode psychosis, consistent with current evidence. Existing literature identified medication attitudes, insight, and characteristics of support as important determinants of adherence to medication: we examined medication attitudes, self-esteem, and insight in an early psychosis cohort better to understand their relationships. Existing longitudinal data from 309 patients with early Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nonaffective psychosis (83% first episode) were analyzed to test the hypothesis that medication attitudes, while meaningfully different from "insight," correlated with insight and self-esteem, and change in each influenced the others. Rosenberg Self-Esteem Scale, Birchwood Insight Scale, and Positive and Negative Syndrome Scale insight were assessed at presentation, after 6 weeks and 3 and 18 months. Drug Attitudes Inventory (DAI) and treatment satisfaction were rated from 6 weeks onward. Structural equation models of their relationships were compared. Insight measures' and DAI's predictive validity were compared against relapse, readmission, and remission. Analysis found five latent constructs best fitted the data: medication attitudes, self-esteem, accepting need for treatment, self-rated insight, and objective insight. All were related and each affected the others as it changed, except self-esteem and medication attitudes. Low self-reported insight at presentation predicted readmission. Good 6-week insight (unlike drug attitudes) predicted remission. Literature review and data modeling indicated that a multimodal intervention using motivational interviewing, online psychoeducation, and SMS text medication reminders to enhance adherence without damaging self-concept was feasible and appropriate. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For

  17. Generalization performance of regularized neural network models

    DEFF Research Database (Denmark)

    Larsen, Jan; Hansen, Lars Kai

    1994-01-01

    Architecture optimization is a fundamental problem of neural network modeling. The optimal architecture is defined as the one which minimizes the generalization error. This paper addresses estimation of the generalization performance of regularized, complete neural network models. Regularization...

  18. The housing, geography, and mobility of Latin American urban poor: the prevailing model and the case of Quito, Ecuador.

    Science.gov (United States)

    Klak, T; Holtzclaw, M

    1993-01-01

    In this study of the constraints of low-income migrants in securing decent housing in Quito, Ecuador (a rapidly growing city), there is a literature review of Latin American intraurban mobility and housing, the development of a theoretical model, and a bivariate analysis. John Turner's model of the three stages in the life cycle of migrants and the three concentric zones of urbanization provides the initial framework for examining Quito migration. Quito differs from other Third World and Latin American cities in that its origins are pre-Colombian, and physical barriers surround the city. Data were obtained from housing data collected independently in 1990 and 1991 and survey data on households living in 1000 inadequate housing units in 1989. 35.5% of Quito's population live in inadequate housing (poor building materials, poor construction, deterioration, or lack of basic services). Three concentric and elongated zones are constructed based on distance from the center city and periphery and are representative of shelter types (rented rooms, shanty, house, and apartment). Shelter improves with type of ownership status. The attitudes of local officials influences the proportion of the poor living in rental or self-help housing. 36% of Quito's low-income residents live in rented rooms, and 38% live in shanties and houses. Bridgeheaders (new migrants who are usually young single males) tend to live in rented rooms for under five years and to move over time to shanties and then houses. Colonial preservation in central Quito and landlords' incentives for encouraging migrants to stay in rental housing interferes with the third phase of the model. Mixed housing throughout the city fits the third phase. Local laws prevent squatters and self-help housing. Rented rooms are primarily in the central city. Occupant income increases with shifts from rented rooms, to shanties, to houses. Shelter, geographic, and mobility patterns that do not fit the model are identified. Urban

  19. Variables used to set PEEP in the lung lavage model are poorly related.

    Science.gov (United States)

    Lichtwarck-Aschoff, M; Hedlund, A J; Nordgren, K A; Wegenius, G A; Markström, A M; Guttmann, J; Sjöstrand, U H

    1999-12-01

    Setting an appropriate positive end-expiratory pressure (PEEP) value is determined by respiratory mechanics, gas exchange and oxygen transport. As these variables may be optimal at different PEEP values, a unique PEEP value may not exist which satisfies both the demands of minimizing mechanical stress and optimizing oxygen transport. In 15 surfactant-deficient piglets, PEEP was increased progressively. Arterial oxygenation and functional residual capacity (FRC) increased, while specific compliance of the respiratory system decreased. Static compliance increased up to a threshold value of PEEP of 8 cm H2O, after which it decreased. This threshold PEEP did not coincide with the lower inflection point of the inspiratory limb of the pressure-volume (PV) loop. Oxygen transport did not correlate with respiratory mechanics or FRC. In the lavage model, the lower inflection point of the PV curve may reflect opening pressure rather than the pressure required to keep the recruited lung open. Recruitment takes place together with a change in the elastic properties of the already open parts of the lung. No single PEEP level is optimal for both oxygen transport and reduction of mechanical stress.

  20. From poor performance to success under stress: working memory, strategy selection, and mathematical problem solving under pressure.

    Science.gov (United States)

    Beilock, Sian L; Decaro, Marci S

    2007-11-01

    Two experiments demonstrate how individual differences in working memory (WM) impact the strategies used to solve complex math problems and how consequential testing situations alter strategy use. In Experiment 1, individuals performed multistep math problems under low- or high-pressure conditions and reported their problem-solving strategies. Under low-pressure conditions, the higher individuals' WM, the more likely they were to use computationally demanding algorithms (vs. simpler shortcuts) to solve the problems, and the more accurate their math performance. Under high-pressure conditions, higher WM individuals used simpler (and less efficacious) problem-solving strategies, and their performance accuracy suffered. Experiment 2 turned the tables by using a math task for which a simpler strategy was optimal (produced accurate performance in few problem steps). Now, under low-pressure conditions, the lower individuals' WM, the better their performance (the more likely they relied on a simple, but accurate, problem strategy). And, under pressure, higher WM individuals performed optimally by using the simpler strategies lower WM individuals employed. WM availability influences how individuals approach math problems, with the nature of the task performed and the performance environment dictating skill success or failure. PsycINFO Database Record (c) 2007 APA, all rights reserved.

  1. Formulating a poorly water soluble drug into an oral solution suitable for paediatric patients; lorazepam as a model drug.

    Science.gov (United States)

    van der Vossen, A C; van der Velde, I; Smeets, O S N M; Postma, D J; Eckhardt, M; Vermes, A; Koch, B C P; Vulto, A G; Hanff, L M

    2017-03-30

    Many drugs are unavailable in suitable oral paediatric dosage forms, and pharmacists often have to compound drugs to provide paediatric patients with an acceptable formulation in the right dose. Liquid formulations offer the advantage of dosing flexibility and ease of administration to young patients, but drug substances often show poor aqueous solubility. The objective of this work was to study different solvents and matrices to design a liquid formulation for poorly water soluble drugs, using lorazepam as model drug. Three different formulation strategies were explored to improve the solubility. Firstly, water-soluble organic solvents were used to improve the aqueous solubility directly, secondly, ionic surfactants were used to solubilise the model drug, and thirdly, complexation of lorazepam with cyclodextrin was studied. Specific attention was paid to excipients, adequate taste correction and palatability. For the final formulation, physical and chemical stability and microbiological quality were assessed for 12months. An organic solvent based formulation, containing a mixture of polyethylene glycol and glycerol 85%, with a minimum amount of propylene glycol, proved to be physically and chemically stable. Development of the non-ionic surfactants formulation was discontinued due to taste problems. The cyclodextrin formulations were physically stable, but lorazepam content declined to 90% within five months. The final formulation contained in volume concentration (%v/v) 87% glycerol, 10% polyethylene glycol 400 and 3% propylene glycol. Orange essence was the preferred taste corrector. The formulation remained stable for 12months at 4°C, with lorazepam content remaining >95%. Related substances increased during the study period but remained below 2%. In-use stability was proven up to 4weeks. An organic solvent based oral formulation was shown to be superior to a non-ionic surfactant based formulation or a cyclodextrin formulation. These results may help to

  2. Provider performance in treating poor patients - factors influencing prescribing practices in lao PDR: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Petzold Max

    2011-01-01

    Full Text Available Abstract Background Out-of-pocket payments make up about 80% of medical care spending at hospitals in Laos, thereby putting poor households at risk of catastrophic health expenditure. Social security schemes in the form of community-based health insurance and health equity funds have been introduced in some parts of the country. Drug and Therapeutics Committees (DTCs have been established to ensure rational use of drugs and improve quality of care. The objective was to assess the appropriateness and expenditure for treatment for poor patients by health care providers at hospitals in three selected provinces of Laos and to explore associated factors. Methods Cross-sectional study using four tracer conditions. Structured interviews with 828 in-patients at twelve provincial and district hospitals on the subject of insurance protection, income and expenditures for treatment, including informal payment. Evaluation of each patient's medical record for appropriateness of drug use using a checklist of treatment guidelines (maximum score = 10. Results No significant difference in appropriateness of care for patients at different income levels, but higher expenditures for patients with the highest income level. The score for appropriate drug use in insured patients was significantly higher than uninsured patients (5.9 vs. 4.9, and the length of stay in days significantly shorter (2.7 vs. 3.7. Insured patients paid significantly less than uninsured patients, both for medicines (USD 14.8 vs. 43.9 and diagnostic tests (USD 5.9 vs. 9.2. On the contrary the score for appropriateness of drug use in patients making informal payments was significantly lower than patients not making informal payments (3.5 vs. 5.1, and the length of stay significantly longer (6.8 vs. 3.2, while expenditures were significantly higher both for medicines (USD 124.5 vs. 28.8 and diagnostic tests (USD 14.1 vs. 7.7. Conclusions The lower expenditure for insured patients can help reduce

  3. Potential role of combined FDG PET/CT and contrast enhancement MRI in a rectal carcinoma model with nodal metastases characterized by a poor FDG-avidity

    International Nuclear Information System (INIS)

    Farace, Paolo; Conti, Giamaica; Merigo, Flavia; Tambalo, Stefano; Marzola, Pasquina; Sbarbati, Andrea; Quarta, Carmelo; D’Ambrosio, Daniela; Chondrogiannis, Sotirios; Nanni, Cristina; Rubello, Domenico

    2012-01-01

    Purpose: To investigate the additional role of MRI contrast enhancement (CE) in the primary tumor and the FDG uptake at PET in the lymph-node metastases. Materials and methods: A model of colorectal cancer induced by orthotopic HT-29 cells microinjection, producing pelvic lymph node metastases, was assessed using CE-MRI and FDG-PET. Histology and GLUT-1 immunohistochemistry were performed on primary tumors and iliac lymph nodes. Results: Primary tumors were characterized by low FDG-uptake but high CE-MRI, particularly at tumor periphery. Undetectable FDG-uptake characterized the metastatic lymph-nodes. Histology revealed large stromal bundles at tumor periphery and a dense network of stromal fibers and neoplastic cells in the inner portion of the tumors. Both primary tumors and positive lymph nodes showed poor GLUT-1 staining. Conclusion: Our data support the complementary role of MRI-CE and FDG PET in some types of carcinomas characterized by abundant cancer-associated stroma and poor FDG avidity consequent to poor GLUT-1 transported. In these tumors FDG-PET alone may be not completely adequate to obtain an adequate tumor radiotherapy planning, and a combination with dual CE-MRI is strongly recommended.

  4. The impact of poor working memory skills on a Grade 2 learner’s written and oral literacy performance

    Directory of Open Access Journals (Sweden)

    Kate Linnegar

    2014-05-01

    Full Text Available This research examines the effects of poor working memory skills on a Grade 2 learner. Mediated learning is the theoretical framework that underpins this research project as the focus is on developing cognitive functions, particularly focusing on the working memory of a learner. An independent case study was conducted on one learner, using a qualitative research approach. Interviews and observations were conducted and inductively analysed. The learner followed a six-week intervention programme which was dynamically informed by recent literature as well as observations, interviews and a psychologist’s report. The findings indicated that the learner’s working memory, with particular reference to processing and storage, was challenged. The large demands of the classroom environment led to memory failure and he was prone to making errors. He experienced slow progress in his reading abilities, was unable to retain words and his reading was inconsistent. To alleviate some of his working memory demands, activities and instructions were broken down into smaller components to minimise his memory load, thus avoiding working memory related failures.

  5. Constrained bayesian inference of project performance models

    OpenAIRE

    Sunmola, Funlade

    2013-01-01

    Project performance models play an important role in the management of project success. When used for monitoring projects, they can offer predictive ability such as indications of possible delivery problems. Approaches for monitoring project performance relies on available project information including restrictions imposed on the project, particularly the constraints of cost, quality, scope and time. We study in this paper a Bayesian inference methodology for project performance modelling in ...

  6. ORGANIZATIONAL LEARNING AND PERFORMANCE. A CONCEPTUAL MODEL

    OpenAIRE

    Alexandra Luciana GUÞÃ

    2013-01-01

    Throught this paper, our main objective is to propose a conceptual model that links the notions of organizational learning (as capability and as a process) and organizational performance. Our contribution consists in analyzing the literature on organizational learning and organizational performance and in proposing an integrated model, that comprises: organizational learning capability, the process of organizational learning, organizational performance, human capital (the value and uniqueness...

  7. Practical advice on how to prevent and manage poorly performing doctors under postgraduate training - acceptance of a one day training course in Denmark

    DEFF Research Database (Denmark)

    Kodal, Troels

    2009-01-01

    "SHORT COMMUNICATION" - ABSTRACTS Practical advice on how to prevent and manage poorly performing doctors under postgraduate training - acceptance of a one day training course in Denmark Troels Kodal*, Allan R ohold, Kirsten Bested, Jonna Skov Madsen, Steen Tinning, Claus Østergaard, Frederik Mørk......, Tine R osengreen Pallisgaard (The Postgraduate Deanery of U niversity of Southern Denmark, HR - Postgraduate Medical Education, R egion of Southern Denmark, Damhaven 1 2, Vejle DK-7100, Denmark) Background: Postgraduate training was reformed in Denmark in 2004 requiring assessment of specific clinical...... skills. This increased the attention on how to manage poorly performing doctors under postgraduate training (PPDUPT). In January 2008 "Managing trainees in difficulty" was published from "National Association of Clinical Tutors UK" providing practical advice for educational and clinical supervisors...

  8. Model performance analysis and model validation in logistic regression

    Directory of Open Access Journals (Sweden)

    Rosa Arboretti Giancristofaro

    2007-10-01

    Full Text Available In this paper a new model validation procedure for a logistic regression model is presented. At first, we illustrate a brief review of different techniques of model validation. Next, we define a number of properties required for a model to be considered "good", and a number of quantitative performance measures. Lastly, we describe a methodology for the assessment of the performance of a given model by using an example taken from a management study.

  9. A rational model for maximizing the effects of therapeutic relationship regulation in personality disorders with poor metacognition and over-regulation of affects.

    Science.gov (United States)

    Dimaggio, Giancarlo; Carcione, Antonino; Salvatore, Giampaolo; Semerari, Antonio; Nicolò, Giuseppe

    2010-11-01

    The therapeutic relationship plays a key role in personality disorder (PD) psychotherapy. Some aspects of therapeutic relationship regulation appear important for treatment of PD clients, including those with constricted relational schemas, poor metacognition, and over-regulation of affects described here. AIM.: To propose a rational model for how and when to work on the therapeutic relationship by treating the underlying personality pathology. Formalize a step-by-step procedure for performing operations such as validation of clients' experiences, creating a sense of sharedness, assessing the quality of the therapeutic relationship in order to prevent and repair ruptures in the alliance, self-disclosing by the therapist, and metacommunication on the basis of clients' responses to treatment. We discuss the implications of this model for further research into the PD therapy process. 2010 The British Psychological Society.

  10. Human performance modeling for system of systems analytics: combat performance-shaping factors.

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Craig R.; Miller, Dwight Peter

    2006-01-01

    The US military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives. To support this goal, Sandia National Laboratories (SNL) has undertaken a program of HPM as an integral augmentation to its system-of-system (SoS) analytics capabilities. The previous effort, reported in SAND2005-6569, evaluated the effects of soldier cognitive fatigue on SoS performance. The current effort began with a very broad survey of any performance-shaping factors (PSFs) that also might affect soldiers performance in combat situations. The work included consideration of three different approaches to cognition modeling and how appropriate they would be for application to SoS analytics. This bulk of this report categorizes 47 PSFs into three groups (internal, external, and task-related) and provides brief descriptions of how each affects combat performance, according to the literature. The PSFs were then assembled into a matrix with 22 representative military tasks and assigned one of four levels of estimated negative impact on task performance, based on the literature. Blank versions of the matrix were then sent to two ex-military subject-matter experts to be filled out based on their personal experiences. Data analysis was performed to identify the consensus most influential PSFs. Results indicate that combat-related injury, cognitive fatigue, inadequate training, physical fatigue, thirst, stress, poor perceptual processing, and presence of chemical agents are among the PSFs with the most negative impact on combat performance.

  11. Short sleep duration is associated with poor performance on IQ measures in healthy school-age children.

    Science.gov (United States)

    Gruber, Reut; Laviolette, Rachelle; Deluca, Paolo; Monson, Eva; Cornish, Kim; Carrier, Julie

    2010-03-01

    To examine the associations between habitual sleep duration and intellectual functioning in healthy, well-rested, school-age children. The study group consisted of 39 healthy children, aged 7-11 years old. Nightly actigraphic sleep recordings were taken for four consecutive nights to determine habitual week-night sleep duration in the home environment. Objective measures of cognitive functioning and sleepiness were used to measure daytime functioning. Longer habitual sleep duration in healthy school-age participants was associated with better performance on measures of perceptual reasoning and overall IQ, as measured by the WISC-IV, and on reported measures of competence and academic performance. No association between sleep duration and the studied behavioral measures was found. These findings support the hypothesis that sleep duration is differentially related to some components of cognitive functioning, even in the absence of evidence for sleep deprivation or attention deficits. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Sleep Disordered Breathing Symptoms and Daytime Sleepiness are Associated with Emotional Problems and Poor School Performance in Children

    OpenAIRE

    Liu, Jianghong; Liu, Xianchen; Ji, Xiaopeng; Wang, Yingjie; Zhou, Guoping; Chen, Xinyin

    2016-01-01

    This study examined the prevalence of sleep disordered breathing (SDB) symptoms and their associations with daytime sleepiness, emotional problems, and school performance in Chinese children. Participants included 3,979 children (10.99 ± 0.99 years old) from four elementary schools in Jintan City, Jiangsu Province, China. Children completed a self-administered questionnaire on sleep behavior and emotional problems, while parents completed the Child Sleep Habit Questionnaire (CSHQ). SDB sympto...

  13. Association of pediatric obstructive sleep apnea with poor academic performance: A school-based study from India

    OpenAIRE

    Abhishek Goyal; Abhijit P Pakhare; Girish C Bhatt; Bharat Choudhary; Rajesh Patil

    2018-01-01

    Background: Pediatric obstructive sleep apnea (OSA) is a highly prevalent but often neglected disorder. There is paucity of reports on the prevalence of pediatric OSA from India. This study was done to estimate the prevalence of OSA in school children aged 5–10 years and its association with academic performance. Methodology: This school-based cross-sectional epidemiological study was conducted from July 2015 to November 2015. A questionnaire seeking information on sociodemographic variables,...

  14. Photovoltaic performance models - A report card

    Science.gov (United States)

    Smith, J. H.; Reiter, L. R.

    1985-01-01

    Models for the analysis of photovoltaic (PV) systems' designs, implementation policies, and economic performance, have proliferated while keeping pace with rapid changes in basic PV technology and extensive empirical data compiled for such systems' performance. Attention is presently given to the results of a comparative assessment of ten well documented and widely used models, which range in complexity from first-order approximations of PV system performance to in-depth, circuit-level characterizations. The comparisons were made on the basis of the performance of their subsystem, as well as system, elements. The models fall into three categories in light of their degree of aggregation into subsystems: (1) simplified models for first-order calculation of system performance, with easily met input requirements but limited capability to address more than a small variety of design considerations; (2) models simulating PV systems in greater detail, encompassing types primarily intended for either concentrator-incorporating or flat plate collector PV systems; and (3) models not specifically designed for PV system performance modeling, but applicable to aspects of electrical system design. Models ignoring subsystem failure or degradation are noted to exclude operating and maintenance characteristics as well.

  15. Human performance modeling for system of systems analytics.

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kevin R.; Lawton, Craig R.; Basilico, Justin Derrick; Longsine, Dennis E. (INTERA, Inc., Austin, TX); Forsythe, James Chris; Gauthier, John Henry; Le, Hai D.

    2008-10-01

    A Laboratory-Directed Research and Development project was initiated in 2005 to investigate Human Performance Modeling in a System of Systems analytic environment. SAND2006-6569 and SAND2006-7911 document interim results from this effort; this report documents the final results. The problem is difficult because of the number of humans involved in a System of Systems environment and the generally poorly defined nature of the tasks that each human must perform. A two-pronged strategy was followed: one prong was to develop human models using a probability-based method similar to that first developed for relatively well-understood probability based performance modeling; another prong was to investigate more state-of-art human cognition models. The probability-based modeling resulted in a comprehensive addition of human-modeling capability to the existing SoSAT computer program. The cognitive modeling resulted in an increased understanding of what is necessary to incorporate cognition-based models to a System of Systems analytic environment.

  16. A “poor man's approach” to topology optimization of cooling channels based on a Darcy flow model

    DEFF Research Database (Denmark)

    Zhao, Xi; Zhou, Mingdong; Sigmund, Ole

    2018-01-01

    . The obtained fluid velocity is subsequently used in a stabilized convection–diffusion heat transfer model to calculate the temperature distribution. The governing equations are cast in a monolithic form such that both the solid and fluid can be modeled using a single equation set. The material properties....... Several numerical examples demonstrate the applicability of this approach. Verification studies with a full turbulence model show that, although the equivalent model has limitations in yielding a perfect realistic velocity field, it generally provides well-performing cooling channel designs....

  17. Estimating Error in SRTM Derived Planform of a River in Data-poor Region and Subsequent Impact on Inundation Modeling

    Science.gov (United States)

    Bhuyian, M. N. M.; Kalyanapu, A. J.

    2017-12-01

    Accurate representation of river planform is critical for hydrodynamic modeling. Digital elevation models (DEM) often falls short in accurately representing river planform because they show the ground as it was during data acquisition. But, water bodies (i.e. rivers) change their size and shape over time. River planforms are more dynamic in undisturbed riverine systems (mostly located in data-poor regions) where remote sensing is the most convenient source of data. For many of such regions, Shuttle Radar Topographic Mission (SRTM) is the best available source of DEM. Therefore, the objective of this study is to estimate the error in SRTM derived planform of a river in a data-poor region and estimate the subsequent impact on inundation modeling. Analysis of Landsat image, SRTM DEM and remotely sensed soil data was used to classify the planform activity in an 185 km stretch of the Kushiyara River in Bangladesh. In last 15 years, the river eroded about 4.65 square km and deposited 7.55 square km area. Therefore, current (the year 2017) river planform is significantly different than the SRTM water body data which represents the time of SRTM data acquisition (the year 2000). The rate of planform shifting significantly increased as the river traveled to downstream. Therefore, the study area was divided into three reaches (R1, R2, and R3) from upstream to downstream. Channel slope and meandering ratio changed from 2x10-7 and 1.64 in R1 to 1x10-4 and 1.45 in R3. However, more than 60% erosion-deposition occurred in R3 where a high percentage of Fluvisols (98%) and coarse particles (21%) were present in the vicinity of the river. It indicates errors in SRTM water body data (due to planform shifting) could be correlated with the physical properties (i.e. slope, soil type, meandering ratio etc.) of the riverine system. The correlations would help in zoning activity of a riverine system and determine a timeline to update DEM for a given region. Additionally, to estimate the

  18. Review of Methods for Buildings Energy Performance Modelling

    Science.gov (United States)

    Krstić, Hrvoje; Teni, Mihaela

    2017-10-01

    Research presented in this paper gives a brief review of methods used for buildings energy performance modelling. This paper gives also a comprehensive review of the advantages and disadvantages of available methods as well as the input parameters used for modelling buildings energy performance. European Directive EPBD obliges the implementation of energy certification procedure which gives an insight on buildings energy performance via exiting energy certificate databases. Some of the methods for buildings energy performance modelling mentioned in this paper are developed by employing data sets of buildings which have already undergone an energy certification procedure. Such database is used in this paper where the majority of buildings in the database have already gone under some form of partial retrofitting – replacement of windows or installation of thermal insulation but still have poor energy performance. The case study presented in this paper utilizes energy certificates database obtained from residential units in Croatia (over 400 buildings) in order to determine the dependence between buildings energy performance and variables from database by using statistical dependencies tests. Building energy performance in database is presented with building energy efficiency rate (from A+ to G) which is based on specific annual energy needs for heating for referential climatic data [kWh/(m2a)]. Independent variables in database are surfaces and volume of the conditioned part of the building, building shape factor, energy used for heating, CO2 emission, building age and year of reconstruction. Research results presented in this paper give an insight in possibilities of methods used for buildings energy performance modelling. Further on it gives an analysis of dependencies between buildings energy performance as a dependent variable and independent variables from the database. Presented results could be used for development of new building energy performance

  19. Moderation of Nicotine Effects on Covert Orienting of Attention Tasks by Poor Placebo Performance and Cue Validity

    Science.gov (United States)

    Gilbert, David G.; Rzetelny, Adam; Rabinovich, Norka E.

    2016-01-01

    Introduction and Rationale Given baseline-dependent effects of nicotine on other forms of attention, there is reason to believe that inconsistent findings for the effects of nicotine on attentional orienting may be partly due to individual differences in baseline (abstinence state) functioning. Individuals with low baseline attention may benefit more from nicotine replacement. Method The effects of nicotine as a function of baseline performance (bottom, middle, and top third of mean reaction times during placebo) were assessed in 52 habitual abstinent smokers (26 females/26 males) utilizing an arrow-cued covert orienting of attention task. Results Compared to a placebo patch, a 14 mg nicotine patch produced faster overall reaction times (RTs). In addition, individuals with slower RTs during the placebo condition benefitted more from nicotine on cued trials than did those who had shorter (faster) RTs during placebo. Nicotine also enhanced the validity effect (shorter RTs to validly vs. invalidly cued targets), but this nicotine benefit did not differ as a function of overall placebo-baseline performance. Conclusions These findings support the view that nicotine enhances cued spatial attentional orienting in individuals who have slower RTs during placebo (nicotine-free) conditions; however, baseline-dependent effects may not generalize to all aspects of spatial attention. These findings are consistent with findings indicating that nicotine’s effects vary as a function of task parameters rather than simple RT speeding or cognitive enhancement. PMID:27461547

  20. Performance on Functional Strength Measurement and Muscle Power Sprint Test confirm poor anaerobic capacity in children with Developmental Coordination Disorder.

    Science.gov (United States)

    Aertssen, Wendy F M; Ferguson, Gillian D; Smits-Engelsman, Bouwien C M

    2016-12-01

    There is little and conflicting information about anaerobic performance and functional strength in children with Developmental Coordination Disorder (DCD). To investigate anaerobic capacity and functional strength in children with a clinical diagnosis of DCD (clin-DCD) and if differences were larger in older (age 7-10 years) compared to younger children (age 4-6 years). Furthermore to determine the percentage of children with clin-DCD that scored Strength Measurement. A clin-DCD group (36 boys, 11 girls, mean age: 7y 1mo, SD=2y 1mo) and a typically developing group (TD) (57 boys, 53 girls, mean age: 7y 5mo, SD=1y 10mo) were compared on Muscle Power Sprint Test (MPST) and Functional Strength Measurement (FSM). Children with clin-DCD performed poorer on the MPST and FSM, especially on the muscle endurance items of the FSM. The differences were larger in the older children compared to the younger on the cluster muscle endurance and the FSM total score. Over 50% of clin-DCD group scored tested on items requiring fast repetitive movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Association between Urine Phthalate Levels and Poor Attentional Performance in Children with Attention-Deficit Hyperactivity Disorder with Evidence of Dopamine Gene-Phthalate Interaction

    Directory of Open Access Journals (Sweden)

    Subin Park

    2014-06-01

    Full Text Available Although there is some evidence supporting the existence of an association between prenatal maternal or postnatal child’s urine phthalate metabolite concentrations and poor attentional performances, the interaction between urine phthalate metabolite levels and genetic variation for neuropsychological deficit of attention-deficit hyperactivity disorder (ADHD has not been examined. The aim of this study was to determine whether phthalate metabolites in urine are associated with poor neuropsychological performance in children with ADHD, and whether such association is affected by genotype-phthalate interaction. A cross-sectional examination of urine phthalate metabolite concentrations and the continuous performance test (CPT were performed in 179 Korean children with ADHD recruited from department of psychiatry of university hospital. Correlations between urine phthalate metabolite concentrations and the CPT scores were investigated, and the interaction of phthalate metabolite levels with the selected polymorphisms at major candidate genes for ADHD, namely dopamine receptor D4 (DRD4, dopamine transporter, α-2A-adrenergic receptor, and norepinephrine transporter genes. For the subjects with the DRD4 4/4 genotype, there were significant associations of the urine phthalate metabolite concentrations with the number of omission errors, the number of commission errors, and the response time variability scores on the CPT. However, for the subjects without the DRD4 4/4 genotype, no significant associations were found. The results of this study suggest a possible association between phthalate metabolite concentrations and poor attentional performances of ADHD as well as a genetic influence on this association. Further prospective and epigenetic studies are needed to investigate causality and pathophysiological mechanisms.

  2. Association between urine phthalate levels and poor attentional performance in children with attention-deficit hyperactivity disorder with evidence of dopamine gene-phthalate interaction.

    Science.gov (United States)

    Park, Subin; Kim, Bung-Nyun; Cho, Soo-Churl; Kim, Yeni; Kim, Jae-Won; Lee, Ju-Young; Hong, Soon-Beom; Shin, Min-Sup; Yoo, Hee Jeong; Im, Hosub; Cheong, Jae Hoon; Han, Doug Hyun

    2014-06-27

    Although there is some evidence supporting the existence of an association between prenatal maternal or postnatal child's urine phthalate metabolite concentrations and poor attentional performances, the interaction between urine phthalate metabolite levels and genetic variation for neuropsychological deficit of attention-deficit hyperactivity disorder (ADHD) has not been examined. The aim of this study was to determine whether phthalate metabolites in urine are associated with poor neuropsychological performance in children with ADHD, and whether such association is affected by genotype-phthalate interaction. A cross-sectional examination of urine phthalate metabolite concentrations and the continuous performance test (CPT) were performed in 179 Korean children with ADHD recruited from department of psychiatry of university hospital. Correlations between urine phthalate metabolite concentrations and the CPT scores were investigated, and the interaction of phthalate metabolite levels with the selected polymorphisms at major candidate genes for ADHD, namely dopamine receptor D4 (DRD4), dopamine transporter, α-2A-adrenergic receptor, and norepinephrine transporter genes. For the subjects with the DRD4 4/4 genotype, there were significant associations of the urine phthalate metabolite concentrations with the number of omission errors, the number of commission errors, and the response time variability scores on the CPT. However, for the subjects without the DRD4 4/4 genotype, no significant associations were found. The results of this study suggest a possible association between phthalate metabolite concentrations and poor attentional performances of ADHD as well as a genetic influence on this association. Further prospective and epigenetic studies are needed to investigate causality and pathophysiological mechanisms.

  3. Iowa calibration of MEPDG performance prediction models.

    Science.gov (United States)

    2013-06-01

    This study aims to improve the accuracy of AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) pavement : performance predictions for Iowa pavement systems through local calibration of MEPDG prediction models. A total of 130 : representative p...

  4. Older adults with poor self-rated memory have less depressive symptoms and better memory performance when perceived self-efficacy is high.

    Science.gov (United States)

    O'Shea, Deirdre M; Dotson, Vonetta M; Fieo, Robert A; Tsapanou, Angeliki; Zahodne, Laura; Stern, Yaakov

    2016-07-01

    To investigate whether self-efficacy moderates the association between self-rated memory and depressive symptoms in a large sample of older adults. The influence of self-efficacy and depressive symptoms on memory performance was also examined in a subsample of individuals who reported poor memory. Non-demented participants (n = 3766) were selected from the 2012 wave of the Health and Retirement Study. Depressive symptomatology was assessed with the 8-item Center for Epidemiologic Studies Depression Scale. A modified version of the Midlife Developmental Inventory Questionnaire was used as the measure of self-efficacy. Participants were asked to rate their memory presently on a five-point scale from Excellent (1) to Poor (5). Immediate memory and delayed memory (after a 5-min interval) were measured by the number of correct words recalled from a 10-item word list. Multiple regression analyses revealed that negative ratings of memory were significantly associated with greater levels of depressive symptoms, with this effect being greatest in those with low levels of self-efficacy. Additionally, greater self-efficacy was associated with optimal objective memory performances but only when depressive symptoms were low in individuals who reported poor memory function (n = 1196). Self-efficacy moderates the relationship between self-rated memory function and depressive symptoms. Higher self-efficacy may buffer against the impact of subjective memory difficulty on one's mood and thereby mitigating the effect of depressive symptoms on memory. Interventions should focus on increasing perceived self-efficacy in older adults reporting poor memory function to potentially minimize memory impairment. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Individualized Biomathematical Modeling of Fatigue and Performance

    Science.gov (United States)

    2008-05-29

    waking period are omitted in order to avoid confounds from sleep inertia. Gray bars indicate scheduled sleep periods . (b) Performance predictions...i.e., total sleep deprivation; black). Light gray areas indicate nocturnal sleep periods . In this illustration, the bifurcation point is set to...confounds from sleep inertia. Gray bars indicate scheduled sleep periods . (b) Corresponding performance predictions according to the new model

  6. Driver Performance Model: 1. Conceptual Framework

    National Research Council Canada - National Science Library

    Heimerl, Joseph

    2001-01-01

    ...'. At the present time, no such comprehensive model exists. This report discusses a conceptual framework designed to encompass the relationships, conditions, and constraints related to direct, indirect, and remote modes of driving and thus provides a guide or 'road map' for the construction and creation of a comprehensive driver performance model.

  7. Performance of hedging strategies in interval models

    NARCIS (Netherlands)

    Roorda, Berend; Engwerda, Jacob; Schumacher, J.M.

    2005-01-01

    For a proper assessment of risks associated with the trading of derivatives, the performance of hedging strategies should be evaluated not only in the context of the idealized model that has served as the basis of strategy development, but also in the context of other models. In this paper we

  8. Analysing the temporal dynamics of model performance for hydrological models

    NARCIS (Netherlands)

    Reusser, D.E.; Blume, T.; Schaefli, B.; Zehe, E.

    2009-01-01

    The temporal dynamics of hydrological model performance gives insights into errors that cannot be obtained from global performance measures assigning a single number to the fit of a simulated time series to an observed reference series. These errors can include errors in data, model parameters, or

  9. Biofilm carrier migration model describes reactor performance.

    Science.gov (United States)

    Boltz, Joshua P; Johnson, Bruce R; Takács, Imre; Daigger, Glen T; Morgenroth, Eberhard; Brockmann, Doris; Kovács, Róbert; Calhoun, Jason M; Choubert, Jean-Marc; Derlon, Nicolas

    2017-06-01

    The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, X carrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of X carrier and associated biofilms, and evaluates the impact that X carrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.

  10. Modeling Local Monetary Flows in Poor Regions: A Research Setup to Simulate the Multiplier Effect in Local Economies

    Directory of Open Access Journals (Sweden)

    Henk van Arkel

    2007-10-01

    Full Text Available In poor regions, lack of local monetary circulation is one of the key elements causing underdevelopment. The more incoming money is passed from hand to hand, the more the local economy will be stimulated. However, in most poor areas money is spent outside the community before circulating locally, reducing the effectiveness of money inflow dramatically.Development programs would increase their effectiveness if knowledge was available on how spending money could lead to optimized and prolonged local circulation. To gain this knowledge a simulation tool will be created, which is able to analyze financial flows, to evaluate the potency of specific actions aimed on local development, and to monitor a development scheme during the execution phase.The basic model will be developed through a multi-agent approach, where each agent represents one (or more family/households belonging to one of several socio-economic groups. A Social Accounting Matrix (SAM of the local economy will be used as a basis to set up a spendings matrix for each agent, defining its spending priorities. Artificial Intelligence techniques will be used to give the agent the possibility to make decisions on how to satisfy these spending priorities. Also, social dynamics, the simulation of strategic planning behavior, learning, and exchange in limited networks will be addressed.The simulation application will consist of a common user interface allowing the user to “play” the simulation. This user interface layer will be “pluggable” with the underlying programming layer responsible for the calculations on the simulation, so that different plug-ins may be used for different simulation techniques.

  11. Performance modeling, loss networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi

    2009-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of understanding the phenomenon of statistical multiplexing. The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the important ideas of Palm distributions associated with traffic models and their role in performance measures. Also presented are recent ideas of large buffer, and many sources asymptotics that play an important role in understanding statistical multiplexing. I

  12. Advances in HTGR fuel performance models

    International Nuclear Information System (INIS)

    Stansfield, O.M.; Goodin, D.T.; Hanson, D.L.; Turner, R.F.

    1985-01-01

    Advances in HTGR fuel performance models have improved the agreement between observed and predicted performance and contributed to an enhanced position of the HTGR with regard to investment risk and passive safety. Heavy metal contamination is the source of about 55% of the circulating activity in the HTGR during normal operation, and the remainder comes primarily from particles which failed because of defective or missing buffer coatings. These failed particles make up about 5 x 10 -4 fraction of the total core inventory. In addition to prediction of fuel performance during normal operation, the models are used to determine fuel failure and fission product release during core heat-up accident conditions. The mechanistic nature of the models, which incorporate all important failure modes, permits the prediction of performance from the relatively modest accident temperatures of a passively safe HTGR to the much more severe accident conditions of the larger 2240-MW/t HTGR. (author)

  13. Performance Evaluation Model for Application Layer Firewalls.

    Directory of Open Access Journals (Sweden)

    Shichang Xuan

    Full Text Available Application layer firewalls protect the trusted area network against information security risks. However, firewall performance may affect user experience. Therefore, performance analysis plays a significant role in the evaluation of application layer firewalls. This paper presents an analytic model of the application layer firewall, based on a system analysis to evaluate the capability of the firewall. In order to enable users to improve the performance of the application layer firewall with limited resources, resource allocation was evaluated to obtain the optimal resource allocation scheme in terms of throughput, delay, and packet loss rate. The proposed model employs the Erlangian queuing model to analyze the performance parameters of the system with regard to the three layers (network, transport, and application layers. Then, the analysis results of all the layers are combined to obtain the overall system performance indicators. A discrete event simulation method was used to evaluate the proposed model. Finally, limited service desk resources were allocated to obtain the values of the performance indicators under different resource allocation scenarios in order to determine the optimal allocation scheme. Under limited resource allocation, this scheme enables users to maximize the performance of the application layer firewall.

  14. Performance Evaluation Model for Application Layer Firewalls.

    Science.gov (United States)

    Xuan, Shichang; Yang, Wu; Dong, Hui; Zhang, Jiangchuan

    2016-01-01

    Application layer firewalls protect the trusted area network against information security risks. However, firewall performance may affect user experience. Therefore, performance analysis plays a significant role in the evaluation of application layer firewalls. This paper presents an analytic model of the application layer firewall, based on a system analysis to evaluate the capability of the firewall. In order to enable users to improve the performance of the application layer firewall with limited resources, resource allocation was evaluated to obtain the optimal resource allocation scheme in terms of throughput, delay, and packet loss rate. The proposed model employs the Erlangian queuing model to analyze the performance parameters of the system with regard to the three layers (network, transport, and application layers). Then, the analysis results of all the layers are combined to obtain the overall system performance indicators. A discrete event simulation method was used to evaluate the proposed model. Finally, limited service desk resources were allocated to obtain the values of the performance indicators under different resource allocation scenarios in order to determine the optimal allocation scheme. Under limited resource allocation, this scheme enables users to maximize the performance of the application layer firewall.

  15. Tailored model abstraction in performance assessments

    International Nuclear Information System (INIS)

    Kessler, J.H.

    1995-01-01

    Total System Performance Assessments (TSPAs) are likely to be one of the most significant parts of making safety cases for the continued development and licensing of geologic repositories for the disposal of spent fuel and HLW. Thus, it is critical that the TSPA model capture the 'essence' of the physical processes relevant to demonstrating the appropriate regulation is met. But how much detail about the physical processes must be modeled and understood before there is enough confidence that the appropriate essence has been captured? In this summary the level of model abstraction that is required is discussed. Approaches for subsystem and total system performance analyses are outlined, and the role of best estimate models is examined. It is concluded that a conservative approach for repository performance, based on limited amount of field and laboratory data, can provide sufficient confidence for a regulatory decision

  16. Scaling up model of social capital: Developing a model of empowerment for poor society in rural areas

    Science.gov (United States)

    Chawa, A. F.; Kusumastuti, A.; Harjo, I. W. W.

    2017-06-01

    Indonesian government has delivered various community development programs to alleviate poverty problems of rural communities. This is despite the fact that the numbers of people who live in poverty in this area is going to increase. This has given rise to a crucial question in how development programs should be distributed to rural community members. This article present empirical findings of research depicts a model or mechanism by which rural community members who have been involved in Posdaya (Pos Pemberdayaan Keluarga/ Family Empowerment Post) program success in achieving economic empowerment objective by employing their social capital. This study employs qualitative method with an approach of case study and multiple case design. It conducts the logic of ‘replica’, meaning that it would lead the analysed case to be used either for making predictions of similar results (literal logic) or for achieving different results (theoretical replica). The fundamental assumption of the study refers to the lack involvement or participation of the empowered community or social groups. The domination of top-down approach has allowed people to rely on external party. On the other hand, bottom-up approach has not been fully implemented due to the absence of strong social capital in the empowered society. As a consequence, there have been only parts of people controlling and enjoying the presented empowerment program. Social capital is not an existing or a given capital in society. Rather, social capital is a mere potential, and in order to shape and develop it some strategies or endeavours are required. Thus, the study attempts to find out a suitable model to arrange and progress the social capital in the implementation of social empowerment program. Additionally, the study will advance the scaling up model into a wider space with an expectation to create a powerful community.

  17. A performance measurement using balanced scorecard and structural equation modeling

    Directory of Open Access Journals (Sweden)

    Rosha Makvandi

    2014-02-01

    Full Text Available During the past few years, balanced scorecard (BSC has been widely used as a promising method for performance measurement. BSC studies organizations in terms of four perspectives including customer, internal processes, learning and growth and financial figures. This paper presents a hybrid of BSC and structural equation modeling (SEM to measure the performance of an Iranian university in province of Alborz, Iran. The proposed study of this paper uses this conceptual method, designs a questionnaire and distributes it among some university students and professors. Using SEM technique, the survey analyzes the data and the results indicate that the university did poorly in terms of all four perspectives. The survey extracts necessary target improvement by presenting necessary attributes for performance improvement.

  18. Estuarine modeling: Does a higher grid resolution improve model performance?

    Science.gov (United States)

    Ecological models are useful tools to explore cause effect relationships, test hypothesis and perform management scenarios. A mathematical model, the Gulf of Mexico Dissolved Oxygen Model (GoMDOM), has been developed and applied to the Louisiana continental shelf of the northern ...

  19. Critical review of glass performance modeling

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process

  20. Critical review of glass performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

  1. Performance modeling, stochastic networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi R

    2013-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of introducing an appropriate mathematical framework for modeling and analysis as well as understanding the phenomenon of statistical multiplexing. The models, techniques, and results presented form the core of traffic engineering methods used to design, control and allocate resources in communication networks.The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the importan

  2. A statistical model for predicting muscle performance

    Science.gov (United States)

    Byerly, Diane Leslie De Caix

    The objective of these studies was to develop a capability for predicting muscle performance and fatigue to be utilized for both space- and ground-based applications. To develop this predictive model, healthy test subjects performed a defined, repetitive dynamic exercise to failure using a Lordex spinal machine. Throughout the exercise, surface electromyography (SEMG) data were collected from the erector spinae using a Mega Electronics ME3000 muscle tester and surface electrodes placed on both sides of the back muscle. These data were analyzed using a 5th order Autoregressive (AR) model and statistical regression analysis. It was determined that an AR derived parameter, the mean average magnitude of AR poles, significantly correlated with the maximum number of repetitions (designated Rmax) that a test subject was able to perform. Using the mean average magnitude of AR poles, a test subject's performance to failure could be predicted as early as the sixth repetition of the exercise. This predictive model has the potential to provide a basis for improving post-space flight recovery, monitoring muscle atrophy in astronauts and assessing the effectiveness of countermeasures, monitoring astronaut performance and fatigue during Extravehicular Activity (EVA) operations, providing pre-flight assessment of the ability of an EVA crewmember to perform a given task, improving the design of training protocols and simulations for strenuous International Space Station assembly EVA, and enabling EVA work task sequences to be planned enhancing astronaut performance and safety. Potential ground-based, medical applications of the predictive model include monitoring muscle deterioration and performance resulting from illness, establishing safety guidelines in the industry for repetitive tasks, monitoring the stages of rehabilitation for muscle-related injuries sustained in sports and accidents, and enhancing athletic performance through improved training protocols while reducing

  3. Screening applicants for risk of poor academic performance: a novel scoring system using preadmission grade point averages and graduate record examination scores.

    Science.gov (United States)

    Luce, David

    2011-01-01

    The purpose of this study was to develop an effective screening tool for identifying physician assistant (PA) program applicants at highest risk for poor academic performance. Prior to reviewing applications for the class of 2009, a retrospective analysis of preadmission data took place for the classes of 2006, 2007, and 2008. A single composite score was calculated for each student who matriculated (number of subjects, N=228) incorporating the total undergraduate grade point average (UGPA), the science GPA (SGPA), and the three component Graduate Record Examination (GRE) scores: verbal (GRE-V), quantitative (GRE-Q), analytical (GRE-A). Individual applicant scores for each of the five parameters were ranked in descending quintiles. Each applicant's five quintile scores were then added, yielding a total quintile score ranging from 25, which indicated an excellent performance, to 5, which indicated poorer performance. Thirteen of the 228 students had academic difficulty (dismissal, suspension, or one-quarter on academic warning or probation). Twelve of the 13 students having academic difficulty had a preadmission total quintile score 12 (range, 6-14). In response to this descriptive analysis, when selecting applicants for the class of 2009, the admissions committee used the total quintile score for screening applicants for interviews. Analysis of correlations in preadmission, graduate, and postgraduate performance data for the classes of 2009-2013 will continue and may help identify those applicants at risk for academic difficulty. Establishing a threshold total quintile score of applicant GPA and GRE scores may significantly decrease the number of entering PA students at risk for poor academic performance.

  4. Evaluation of models in performance assessment

    International Nuclear Information System (INIS)

    Dormuth, K.W.

    1993-01-01

    The reliability of models used for performance assessment for high-level waste repositories is a key factor in making decisions regarding the management of high-level waste. Model reliability may be viewed as a measure of the confidence that regulators and others have in the use of these models to provide information for decision making. The degree of reliability required for the models will increase as implementation of disposal proceeds and decisions become increasingly important to safety. Evaluation of the models by using observations of real systems provides information that assists the assessment analysts and reviewers in establishing confidence in the conclusions reached in the assessment. A continuing process of model calibration, evaluation, and refinement should lead to increasing reliability of models as implementation proceeds. However, uncertainty in the model predictions cannot be eliminated, so decisions will always be made under some uncertainty. Examples from the Canadian program illustrate the process of model evaluation using observations of real systems and its relationship to performance assessment. 21 refs., 2 figs

  5. Generating Performance Models for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

    2017-05-30

    Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

  6. Performance Measurement Model A TarBase model with ...

    Indian Academy of Sciences (India)

    rohit

    Model A 8.0 2.0 94.52% 88.46% 76 108 12 12 0.86 0.91 0.78 0.94. Model B 2.0 2.0 93.18% 89.33% 64 95 10 9 0.88 0.90 0.75 0.98. The above results for TEST – 1 show details for our two models (Model A and Model B).Performance of Model A after adding of 32 negative dataset of MiRTif on our testing set(MiRecords) ...

  7. Performance Evaluation and Modelling of Container Terminals

    Science.gov (United States)

    Venkatasubbaiah, K.; Rao, K. Narayana; Rao, M. Malleswara; Challa, Suresh

    2018-02-01

    The present paper evaluates and analyzes the performance of 28 container terminals of south East Asia through data envelopment analysis (DEA), principal component analysis (PCA) and hybrid method of DEA-PCA. DEA technique is utilized to identify efficient decision making unit (DMU)s and to rank DMUs in a peer appraisal mode. PCA is a multivariate statistical method to evaluate the performance of container terminals. In hybrid method, DEA is integrated with PCA to arrive the ranking of container terminals. Based on the composite ranking, performance modelling and optimization of container terminals is carried out through response surface methodology (RSM).

  8. Tuberculosis Case Finding in HIV-Infected Pregnant Women in Kenya Reveals Poor Performance of Symptom Screening and Rapid Diagnostic Tests.

    Science.gov (United States)

    LaCourse, Sylvia M; Cranmer, Lisa M; Matemo, Daniel; Kinuthia, John; Richardson, Barbra A; John-Stewart, Grace; Horne, David J

    2016-02-01

    Tuberculosis (TB) during pregnancy in HIV-infected women is associated with poor maternal and infant outcomes. There are limited data on TB prevalence, optimal TB screening, and performance of rapid diagnostics in pregnant HIV-infected women. We conducted a cross-sectional study among HIV-infected pregnant women seeking antenatal care in western Kenya. After a standardized questionnaire, sputum smear microscopy for acid-fast bacilli, mycobacterial liquid culture, GeneXpert MTB/RIF (Xpert), urine lipoarabinomannan, and tuberculin skin testing were performed. We determined prevalence and correlates of culture-confirmed pulmonary TB, and compared diagnostic performance of World Health Organization (WHO) symptom screening and rapid diagnostic tests to sputum culture. Between July 2013 and July 2014, we enrolled 306 women. Among 288 women with a valid sputum culture result, 54% were on antiretroviral treatment, median CD4 cell count was 437 cell per cubic millimeter (IQR 342-565), and prevalence of culture-confirmed pulmonary TB was 2.4% (confidence interval: 1.0% to 4.9%). Cough >2 weeks (P = 0.04) and positive tuberculin skin testing (≥ 5 mm, P = 0.03) were associated with pulmonary TB. Women with TB were 23-fold (95% confidence interval: 4.4 to 116.6) more likely to report a household member with TB symptoms (P = 0.002). WHO symptom screen (43%), acid-fast bacilli smear (0%), Xpert (43%), and lipoarabinomannan (0%) had low sensitivity but high specificity (81%, 99%, 99%, and 95%, respectively) for pulmonary TB. HIV-infected pregnant women had appreciable prevalence of pulmonary TB despite modest immunosuppression. Current TB screening and diagnostic tools perform poorly in pregnant HIV-infected women. Adapted TB screening tools that include household member TB symptoms may be useful in this population.

  9. Early maternal age at first birth is associated with chronic diseases and poor physical performance in older age: cross-sectional analysis from the International Mobility in Aging Study.

    Science.gov (United States)

    Pirkle, Catherine M; de Albuquerque Sousa, Ana Carolina Patrício; Alvarado, Beatriz; Zunzunegui, Maria-Victoria

    2014-03-31

    Early maternal age at first birth and elevated parity may have long-term consequences for the health of women as they age. Both are known risk factors for obstetrical complications with lifelong associated morbidities. They may also be related to diabetes and cardiovascular disease development. We examine the relationship between early maternal age at first birth, defined as ≤18 years of age, multiparity (>2 births), and poor physical performance (Short Physical Performance Battery≤8) in community samples of women between 65 and 74 years of age from Canada, Albania, Colombia, and Brazil (N=1040). Data were collected in 2012 to provide a baseline assessment for a longitudinal cohort called the International Mobility in Aging Study. We used logistic regression and general linear models to analyse the data. Early maternal age at first birth is significantly associated with diabetes, chronic lung disease, high blood pressure, and poor physical performance in women at older ages. Parity was not independently associated with chronic conditions and physical performance in older age. After adjustment for study site, age, education, childhood economic adversity and lifetime births, women who gave birth at a young age had 1.75 (95% CI: 1.17-2.64) the odds of poor SPPB compared to women who gave birth>18 years of age. Adjustment for chronic diseases attenuated the association between early first birth and physical performance. Results were weaker in Colombia and Brazil, than Canada and Albania. This study provides evidence that adolescent childbirth may increase the risk of developing chronic diseases and physical limitations in older age. Results likely reflect both the biological and social consequences of early childbearing and if the observed relationship is causal, it reinforces the importance of providing contraception and sex education to young women, as the consequences of early pregnancy may be life-long.

  10. Utilities for high performance dispersion model PHYSIC

    International Nuclear Information System (INIS)

    Yamazawa, Hiromi

    1992-09-01

    The description and usage of the utilities for the dispersion calculation model PHYSIC were summarized. The model was developed in the study of developing high performance SPEEDI with the purpose of introducing meteorological forecast function into the environmental emergency response system. The procedure of PHYSIC calculation consists of three steps; preparation of relevant files, creation and submission of JCL, and graphic output of results. A user can carry out the above procedure with the help of the Geographical Data Processing Utility, the Model Control Utility, and the Graphic Output Utility. (author)

  11. Sleep Disordered Breathing And Daytime Sleepiness Are Associated With Poor Academic Performance In Teenagers. A Study Using The Pediatric Daytime Sleepiness Scale (PDSS)

    Science.gov (United States)

    Perez-Chada, Daniel; Perez-Lloret, Santiago; Videla, Alejandro J.; Cardinali, Daniel; Bergna, Miguel A.; Fernández-Acquier, Mariano; Larrateguy, Luis; Zabert, Gustavo E.; Drake, Christopher

    2007-01-01

    Study Objectives: Inadequate sleep and sleep disordered breathing (SDB) can impair learning skills. Questionnaires used to evaluate sleepiness in adults are usually inadequate for adolescents. We conducted a study to evaluate the performance of a Spanish version of the Pediatric Daytime Sleepiness Scale (PDSS) and to assess the impact of sleepiness and SDB on academic performance. Design: A cross-sectional survey of students from 7 schools in 4 cities of Argentina. Measurements: A questionnaire with a Spanish version of the PDSS was used. Questions on the occurrence of snoring and witnessed apneas were answered by the parents. Mathematics and language grades were used as indicators of academic performance. Participants: The sample included 2,884 students (50% males; age: 13.3 ± 1.5 years) Results: Response rate was 85%; 678 cases were excluded due to missing data. Half the students slept academic performance. Citation: Perez-Chada D; Perez-Lloret S; Videla AJ; Cardinali D; Bergna MA; Fernández-Acquier M; Larrateguy L; Zabert GE; Drake C. Sleep disordered breathing and daytime sleepiness are associated with poor academic performance in teenagers. A study using the pediatric daytime sleepiness scale (PDSS). SLEEP 2007;30(12):1698-1703. PMID:18246979

  12. A practical model for sustainable operational performance

    International Nuclear Information System (INIS)

    Vlek, C.A.J.; Steg, E.M.; Feenstra, D.; Gerbens-Leenis, W.; Lindenberg, S.; Moll, H.; Schoot Uiterkamp, A.; Sijtsma, F.; Van Witteloostuijn, A.

    2002-01-01

    By means of a concrete model for sustainable operational performance enterprises can report uniformly on the sustainability of their contributions to the economy, welfare and the environment. The development and design of a three-dimensional monitoring system is presented and discussed [nl

  13. Data Model Performance in Data Warehousing

    Science.gov (United States)

    Rorimpandey, G. C.; Sangkop, F. I.; Rantung, V. P.; Zwart, J. P.; Liando, O. E. S.; Mewengkang, A.

    2018-02-01

    Data Warehouses have increasingly become important in organizations that have large amount of data. It is not a product but a part of a solution for the decision support system in those organizations. Data model is the starting point for designing and developing of data warehouses architectures. Thus, the data model needs stable interfaces and consistent for a longer period of time. The aim of this research is to know which data model in data warehousing has the best performance. The research method is descriptive analysis, which has 3 main tasks, such as data collection and organization, analysis of data and interpretation of data. The result of this research is discussed in a statistic analysis method, represents that there is no statistical difference among data models used in data warehousing. The organization can utilize four data model proposed when designing and developing data warehouse.

  14. Performance model for a CCTV-MTI

    International Nuclear Information System (INIS)

    Dunn, D.R.; Dunbar, D.L.

    1978-01-01

    CCTV-MTI (closed circuit television--moving target indicator) monitors represent typical components of access control systems, as for example in a material control and accounting (MC and A) safeguards system. This report describes a performance model for a CCTV-MTI monitor. The performance of a human in an MTI role is a separate problem and is not addressed here. This work was done in conjunction with the NRC sponsored LLL assessment procedure for MC and A systems which is presently under development. We develop a noise model for a generic camera system and a model for the detection mechanism for a postulated MTI design. These models are then translated into an overall performance model. Measures of performance are probabilities of detection and false alarm as a function of intruder-induced grey level changes in the protected area. Sensor responsivity, lens F-number, source illumination and spectral response were treated as design parameters. Some specific results are illustrated for a postulated design employing a camera with a Si-target vidicon. Reflectance or light level changes in excess of 10% due to an intruder will be detected with a very high probability for the portion of the visible spectrum with wavelengths above 500 nm. The resulting false alarm rate was less than one per year. We did not address sources of nuisance alarms due to adverse environments, reliability, resistance to tampering, nor did we examine the effects of the spatial frequency response of the optics. All of these are important and will influence overall system detection performance

  15. Formulating a poorly water soluble drug into an oral solution suitable for paediatric patients; lorazepam as a model drug

    OpenAIRE

    van der Vossen, A.C.; van der Velde, I.; Smeets, O.S.N.M.; Postma, D.J.; Eckhardt, M.; Vermes, A.; Koch, B.C.P.; Vulto, A.G.; Hanff, L.M.

    2017-01-01

    textabstractIntroduction Many drugs are unavailable in suitable oral paediatric dosage forms, and pharmacists often have to compound drugs to provide paediatric patients with an acceptable formulation in the right dose. Liquid formulations offer the advantage of dosing flexibility and ease of administration to young patients, but drug substances often show poor aqueous solubility. The objective of this work was to study different solvents and matrices to design a liquid formulation for poorly...

  16. Assessing The Performance of Hydrological Models

    Science.gov (United States)

    van der Knijff, Johan

    The performance of hydrological models is often characterized using the coefficient of efficiency, E. The sensitivity of E to extreme streamflow values, and the difficulty of deciding what value of E should be used as a threshold to identify 'good' models or model parameterizations, have proven to be serious shortcomings of this index. This paper reviews some alternative performance indices that have appeared in the litera- ture. Legates and McCabe (1999) suggested a more generalized form of E, E'(j,B). Here, j is a parameter that controls how much emphasis is put on extreme streamflow values, and B defines a benchmark or 'null hypothesis' against which the results of the model are tested. E'(j,B) was used to evaluate a large number of parameterizations of a conceptual rainfall-runoff model, using 6 different combinations of j and B. First, the effect of j and B is explained. Second, it is demonstrated how the index can be used to explicitly test hypotheses about the model and the data. This approach appears to be particularly attractive if the index is used as a likelihood measure within a GLUE-type analysis.

  17. Sleep disordered breathing and daytime sleepiness are associated with poor academic performance in teenagers. A study using the Pediatric Daytime Sleepiness Scale (PDSS).

    Science.gov (United States)

    Perez-Chada, Daniel; Perez-Lloret, Santiago; Videla, Alejandro J; Cardinali, Daniel; Bergna, Miguel A; Fernández-Acquier, Mariano; Larrateguy, Luis; Zabert, Gustavo E; Drake, Christopher

    2007-12-01

    Inadequate sleep and sleep disordered breathing (SDB) can impair learning skills. Questionnaires used to evaluate sleepiness in adults are usually inadequate for adolescents. We conducted a study to evaluate the performance of a Spanish version of the Pediatric Daytime Sleepiness Scale (PDSS) and to assess the impact of sleepiness and SDB on academic performance. A cross-sectional survey of students from 7 schools in 4 cities of Argentina. A questionnaire with a Spanish version of the PDSS was used. Questions on the occurrence of snoring and witnessed apneas were answered by the parents. Mathematics and language grades were used as indicators of academic performance. The sample included 2,884 students (50% males; age: 13.3 +/- 1.5 years) Response rate was 85%; 678 cases were excluded due to missing data. Half the students slept sleep habits. Insufficient hours of sleep were prevalent in this population. The Spanish version of the PDSS was a reliable tool in middle-school-aged children. Reports of snoring or witnessed apneas and daytime sleepiness as measured by PDSS were independent predictors of poor academic performance.

  18. System Advisor Model: Flat Plate Photovoltaic Performance Modeling Validation Report

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, Janine [National Renewable Energy Lab. (NREL), Golden, CO (United States); Whitmore, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kaffine, Leah [National Renewable Energy Lab. (NREL), Golden, CO (United States); Blair, Nate [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron P. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-12-01

    The System Advisor Model (SAM) is a free software tool that performs detailed analysis of both system performance and system financing for a variety of renewable energy technologies. This report provides detailed validation of the SAM flat plate photovoltaic performance model by comparing SAM-modeled PV system generation data to actual measured production data for nine PV systems ranging from 75 kW to greater than 25 MW in size. The results show strong agreement between SAM predictions and field data, with annualized prediction error below 3% for all fixed tilt cases and below 8% for all one axis tracked cases. The analysis concludes that snow cover and system outages are the primary sources of disagreement, and other deviations resulting from seasonal biases in the irradiation models and one axis tracking issues are discussed in detail.

  19. New Diagnostics to Assess Model Performance

    Science.gov (United States)

    Koh, Tieh-Yong

    2013-04-01

    The comparison of model performance between the tropics and the mid-latitudes is particularly problematic for observables like temperature and humidity: in the tropics, these observables have little variation and so may give an apparent impression that model predictions are often close to observations; on the contrary, they vary widely in mid-latitudes and so the discrepancy between model predictions and observations might be unnecessarily over-emphasized. We have developed a suite of mathematically rigorous diagnostics that measures normalized errors accounting for the observed and modeled variability of the observables themselves. Another issue in evaluating model performance is the relative importance of getting the variance of an observable right versus getting the modeled variation to be in phase with the observed. The correlation-similarity diagram was designed to analyse the pattern error of a model by breaking it down into contributions from amplitude and phase errors. A final and important question pertains to the generalization of scalar diagnostics to analyse vector observables like wind. In particular, measures of variance and correlation must be properly derived to avoid the mistake of ignoring the covariance between north-south and east-west winds (hence wrongly assuming that the north-south and east-west directions form a privileged vector basis for error analysis). There is also a need to quantify systematic preferences in the direction of vector wind errors, which we make possible by means of an error anisotropy diagram. Although the suite of diagnostics is mentioned with reference to model verification here, it is generally applicable to quantify differences between two datasets (e.g. from two observation platforms). Reference publication: Koh, T. Y. et al. (2012), J. Geophys. Res., 117, D13109, doi:10.1029/2011JD017103. also available at http://www.ntu.edu.sg/home/kohty

  20. Performance modeling of network data services

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, R.A.; Pierson, L.G.

    1997-01-01

    Networks at major computational organizations are becoming increasingly complex. The introduction of large massively parallel computers and supercomputers with gigabyte memories are requiring greater and greater bandwidth for network data transfers to widely dispersed clients. For networks to provide adequate data transfer services to high performance computers and remote users connected to them, the networking components must be optimized from a combination of internal and external performance criteria. This paper describes research done at Sandia National Laboratories to model network data services and to visualize the flow of data from source to sink when using the data services.

  1. Probabilistic Radiological Performance Assessment Modeling and Uncertainty

    Science.gov (United States)

    Tauxe, J.

    2004-12-01

    A generic probabilistic radiological Performance Assessment (PA) model is presented. The model, built using the GoldSim systems simulation software platform, concerns contaminant transport and dose estimation in support of decision making with uncertainty. Both the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE) require assessments of potential future risk to human receptors of disposal of LLW. Commercially operated LLW disposal facilities are licensed by the NRC (or agreement states), and the DOE operates such facilities for disposal of DOE-generated LLW. The type of PA model presented is probabilistic in nature, and hence reflects the current state of knowledge about the site by using probability distributions to capture what is expected (central tendency or average) and the uncertainty (e.g., standard deviation) associated with input parameters, and propagating through the model to arrive at output distributions that reflect expected performance and the overall uncertainty in the system. Estimates of contaminant release rates, concentrations in environmental media, and resulting doses to human receptors well into the future are made by running the model in Monte Carlo fashion, with each realization representing a possible combination of input parameter values. Statistical summaries of the results can be compared to regulatory performance objectives, and decision makers are better informed of the inherently uncertain aspects of the model which supports their decision-making. While this information may make some regulators uncomfortable, they must realize that uncertainties which were hidden in a deterministic analysis are revealed in a probabilistic analysis, and the chance of making a correct decision is now known rather than hoped for. The model includes many typical features and processes that would be part of a PA, but is entirely fictitious. This does not represent any particular site and is meant to be a generic example. A

  2. Randomized phase II study of gefitinib compared with placebo in chemotherapy-naive patients with advanced non-small-cell lung cancer and poor performance status.

    Science.gov (United States)

    Goss, Glenwood; Ferry, David; Wierzbicki, Rafal; Laurie, Scott A; Thompson, Joyce; Biesma, Bonne; Hirsch, Fred R; Varella-Garcia, Marileila; Duffield, Emma; Ataman, Ozlem U; Zarenda, Marc; Armour, Alison A

    2009-05-01

    To compare gefitinib with placebo in chemotherapy naïve patients with advanced non-small-cell lung cancer (NSCLC) and poor performance status. NSCLC patients (chemotherapy naïve, WHO performance status 2 or 3; unfit for chemotherapy; stage IIIB/IV) were randomly assigned to gefitinib (250 mg/d) plus best supportive care (BSC; n = 100) or placebo plus BSC (n = 101). The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), quality of life (QOL), pulmonary symptom improvement (PSI), and safety. Correlation of gefitinib efficacy with EGFR gene copy number (fluorescent in situ hybridization [FISH]) was explored. Hazard ratios (HRs; gefitinib:placebo) were 0.82 (95% CI, 0.60 to 1.12; P = .217) for PFS and 0.84 (95% CI, 0.62 to 1.15; P = .272) for OS. As expected for this patient population, OS for both arms was poor, at about 3 months. ORRs were 6.0% (gefitinib) and 1.0% (placebo). QOL and PSI rates were 21.1% and 28.3% (gefitinib) and 20.0% and 28.3% (placebo), respectively. In EGFR FISH-positive patients (n = 32), HRs were 0.29 (95% CI, 0.11 to 0.73) for PFS and 0.44 (95% CI, 0.17 to 1.12) for OS. No unexpected adverse events occurred. There was no statistically significant difference in PFS, OS, and ORRs after treatment with gefitinib or placebo, in the overall population; improvements in QOL and symptoms were similar in both groups. Tolerability profile of gefitinib was consistent with previous studies. PFS was statistically significantly improved for gefitinib-treated patients with EGFR FISH-positive tumors.

  3. Randomized Phase II Study of Gefitinib Compared With Placebo in Chemotherapy-Naive Patients With Advanced Non–Small-Cell Lung Cancer and Poor Performance Status

    Science.gov (United States)

    Goss, Glenwood; Ferry, David; Wierzbicki, Rafal; Laurie, Scott A.; Thompson, Joyce; Biesma, Bonne; Hirsch, Fred R.; Varella-Garcia, Marileila; Duffield, Emma; Ataman, Ozlem U.; Zarenda, Marc; Armour, Alison A.

    2009-01-01

    Purpose To compare gefitinib with placebo in chemotherapy naïve patients with advanced non–small-cell lung cancer (NSCLC) and poor performance status. Patients and Methods NSCLC patients (chemotherapy naïve, WHO performance status 2 or 3; unfit for chemotherapy; stage IIIB/IV) were randomly assigned to gefitinib (250 mg/d) plus best supportive care (BSC; n = 100) or placebo plus BSC (n = 101). The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), quality of life (QOL), pulmonary symptom improvement (PSI), and safety. Correlation of gefitinib efficacy with EGFR gene copy number (fluorescent in situ hybridization [FISH]) was explored. Results Hazard ratios (HRs; gefitinib:placebo) were 0.82 (95% CI, 0.60 to 1.12; P = .217) for PFS and 0.84 (95% CI, 0.62 to 1.15; P = .272) for OS. As expected for this patient population, OS for both arms was poor, at about 3 months. ORRs were 6.0% (gefitinib) and 1.0% (placebo). QOL and PSI rates were 21.1% and 28.3% (gefitinib) and 20.0% and 28.3% (placebo), respectively. In EGFR FISH-positive patients (n = 32), HRs were 0.29 (95% CI, 0.11 to 0.73) for PFS and 0.44 (95% CI, 0.17 to 1.12) for OS. No unexpected adverse events occurred. Conclusion There was no statistically significant difference in PFS, OS, and ORRs after treatment with gefitinib or placebo, in the overall population; improvements in QOL and symptoms were similar in both groups. Tolerability profile of gefitinib was consistent with previous studies. PFS was statistically significantly improved for gefitinib-treated patients with EGFR FISH-positive tumors. PMID:19289623

  4. Performance assessment modeling of pyrometallurgical process wasteforms

    International Nuclear Information System (INIS)

    Nutt, W.M.; Hill, R.N.; Bullen, D.B.

    1995-01-01

    Performance assessment analyses have been completed to estimate the behavior of high-level nuclear wasteforms generated from the pyrometallurgical processing of liquid metal reactor (LMR) and light water reactor (LWR) spent nuclear fuel. Waste emplaced in the proposed repository at Yucca Mountain is investigated as the basis for the study. The resulting cumulative actinide and fission product releases to the accessible environment within a 100,000 year period from the various pyrometallurgical process wasteforms are compared to those of directly disposed LWR spent fuel using the same total repository system model. The impact of differing radionuclide transport models on the overall release characteristics is investigated

  5. Model description and evaluation of model performance: DOSDIM model

    International Nuclear Information System (INIS)

    Lewyckyj, N.; Zeevaert, T.

    1996-01-01

    DOSDIM was developed to assess the impact to man from routine and accidental atmospheric releases. It is a compartmental, deterministic, radiological model. For an accidental release, dynamic transfer are used in opposition to a routine release for which equilibrium transfer factors are used. Parameters values were chosen to be conservative. Transfer between compartments are described by first-order differential equations. 2 figs

  6. Modelling and evaluation of surgical performance using hidden Markov models.

    Science.gov (United States)

    Megali, Giuseppe; Sinigaglia, Stefano; Tonet, Oliver; Dario, Paolo

    2006-10-01

    Minimally invasive surgery has become very widespread in the last ten years. Since surgeons experience difficulties in learning and mastering minimally invasive techniques, the development of training methods is of great importance. While the introduction of virtual reality-based simulators has introduced a new paradigm in surgical training, skill evaluation methods are far from being objective. This paper proposes a method for defining a model of surgical expertise and an objective metric to evaluate performance in laparoscopic surgery. Our approach is based on the processing of kinematic data describing movements of surgical instruments. We use hidden Markov model theory to define an expert model that describes expert surgical gesture. The model is trained on kinematic data related to exercises performed on a surgical simulator by experienced surgeons. Subsequently, we use this expert model as a reference model in the definition of an objective metric to evaluate performance of surgeons with different abilities. Preliminary results show that, using different topologies for the expert model, the method can be efficiently used both for the discrimination between experienced and novice surgeons, and for the quantitative assessment of surgical ability.

  7. Hybrid Modeling Improves Health and Performance Monitoring

    Science.gov (United States)

    2007-01-01

    Scientific Monitoring Inc. was awarded a Phase I Small Business Innovation Research (SBIR) project by NASA's Dryden Flight Research Center to create a new, simplified health-monitoring approach for flight vehicles and flight equipment. The project developed a hybrid physical model concept that provided a structured approach to simplifying complex design models for use in health monitoring, allowing the output or performance of the equipment to be compared to what the design models predicted, so that deterioration or impending failure could be detected before there would be an impact on the equipment's operational capability. Based on the original modeling technology, Scientific Monitoring released I-Trend, a commercial health- and performance-monitoring software product named for its intelligent trending, diagnostics, and prognostics capabilities, as part of the company's complete ICEMS (Intelligent Condition-based Equipment Management System) suite of monitoring and advanced alerting software. I-Trend uses the hybrid physical model to better characterize the nature of health or performance alarms that result in "no fault found" false alarms. Additionally, the use of physical principles helps I-Trend identify problems sooner. I-Trend technology is currently in use in several commercial aviation programs, and the U.S. Air Force recently tapped Scientific Monitoring to develop next-generation engine health-management software for monitoring its fleet of jet engines. Scientific Monitoring has continued the original NASA work, this time under a Phase III SBIR contract with a joint NASA-Pratt & Whitney aviation security program on propulsion-controlled aircraft under missile-damaged aircraft conditions.

  8. Pre- and in-therapy predictive score models of adult OSAS patients with poor adherence pattern on nCPAP therapy

    Directory of Open Access Journals (Sweden)

    Wang Y

    2015-05-01

    Full Text Available Yeying Wang,1,2 Alan F Geater,3 Yanling Chai,1 Jiahong Luo,2 Xiaoqun Niu,1 Bing Hai,1 Jingting Qin,1 Yongxia Li1 1Department of Respiratory Medicine, The 2nd Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, People’s Republic of China; 2Department of Epidemiology and Biostatistics, School of Public Health, Kunming Medical University, Kunming, Yunnan Province, People’s Republic of China; 3Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand Objectives: To identify patterns of adherence to nasal continuous positive airway pressure (nCPAP use in the first 3 months of therapy among newly diagnosed adult patients with obstructive sleep apnea/hypopnea syndrome (OSAS and their predictors. To develop pretherapy and in-therapy scores to predict adherence pattern. Methods: Newly diagnosed adult OSAS patients were consecutively recruited from March to August 2013. Baseline clinical information and measures such as Epworth Sleepiness Scale (ESS, Fatigue Severity Scale (FSS, Zung’s Self-Rating Depression Scale (SDS, and The Pittsburgh Sleep Quality Index (PSQI at baseline and at the end of 3rd-week therapy were collected. Twelve weeks’ adherence data were collected from the nCPAP memory card, and K-means cluster analysis was used to explore adherence patterns. Predictive scores were developed from the coefficients of cumulative logit models of adherence patterns using variables available at baseline and after 3 weeks of therapy. Performance of the score was validated using 500 bootstrap resamples. Results: Seventy six patients completed a 12-week follow-up. Three patterns were revealed. Patients were identified as developing an adherence pattern that was poor (n=14, mean ± SD, 2.3±0.9 hours per night, moderate (n=19, 5.3±0.6 hours per night, or good (n=43, 6.8±0.3 hours per night. Cumulative logit regression models (good → moderate → poor revealed independent baseline

  9. Modelling fuel cell performance using artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Ogaji, S.O.T.; Singh, R.; Pilidis, P.; Diacakis, M. [Power Propulsion and Aerospace Engineering Department, Centre for Diagnostics and Life Cycle Costs, Cranfield University (United Kingdom)

    2006-03-09

    Over the last few years, fuel cell technology has been increasing promisingly its share in the generation of stationary power. Numerous pilot projects are operating worldwide, continuously increasing the amount of operating hours either as stand-alone devices or as part of gas turbine combined cycles. An essential tool for the adequate and dynamic analysis of such systems is a software model that enables the user to assess a large number of alternative options in the least possible time. On the other hand, the sphere of application of artificial neural networks has widened covering such endeavours of life such as medicine, finance and unsurprisingly engineering (diagnostics of faults in machines). Artificial neural networks have been described as diagrammatic representation of a mathematical equation that receives values (inputs) and gives out results (outputs). Artificial neural networks systems have the capacity to recognise and associate patterns and because of their inherent design features, they can be applied to linear and non-linear problem domains. In this paper, the performance of the fuel cell is modelled using artificial neural networks. The inputs to the network are variables that are critical to the performance of the fuel cell while the outputs are the result of changes in any one or all of the fuel cell design variables, on its performance. Critical parameters for the cell include the geometrical configuration as well as the operating conditions. For the neural network, various network design parameters such as the network size, training algorithm, activation functions and their causes on the effectiveness of the performance modelling are discussed. Results from the analysis as well as the limitations of the approach are presented and discussed. (author)

  10. Modelling fuel cell performance using artificial intelligence

    Science.gov (United States)

    Ogaji, S. O. T.; Singh, R.; Pilidis, P.; Diacakis, M.

    Over the last few years, fuel cell technology has been increasing promisingly its share in the generation of stationary power. Numerous pilot projects are operating worldwide, continuously increasing the amount of operating hours either as stand-alone devices or as part of gas turbine combined cycles. An essential tool for the adequate and dynamic analysis of such systems is a software model that enables the user to assess a large number of alternative options in the least possible time. On the other hand, the sphere of application of artificial neural networks has widened covering such endeavours of life such as medicine, finance and unsurprisingly engineering (diagnostics of faults in machines). Artificial neural networks have been described as diagrammatic representation of a mathematical equation that receives values (inputs) and gives out results (outputs). Artificial neural networks systems have the capacity to recognise and associate patterns and because of their inherent design features, they can be applied to linear and non-linear problem domains. In this paper, the performance of the fuel cell is modelled using artificial neural networks. The inputs to the network are variables that are critical to the performance of the fuel cell while the outputs are the result of changes in any one or all of the fuel cell design variables, on its performance. Critical parameters for the cell include the geometrical configuration as well as the operating conditions. For the neural network, various network design parameters such as the network size, training algorithm, activation functions and their causes on the effectiveness of the performance modelling are discussed. Results from the analysis as well as the limitations of the approach are presented and discussed.

  11. A functional model for monitoring equity and effectiveness in purchasing health insurance premiums for the poor: evidence from Cambodia and the Lao PDR.

    Science.gov (United States)

    Annear, Peter Leslie; Bigdeli, Maryam; Jacobs, Bart

    2011-10-01

    To assess the impact on equity and effectiveness of introducing targeted subsidies for the poor into existing voluntary health insurance schemes in Low Income Countries with special reference to cross-subsidisation. A functional model was constructed using routine collected financial data to analyse changes in financial flows and resulting shifts in cross-subsidization between poor and non-poor. Data were collected from two sites, in Cambodia at Kampot operational health district and in the Lao People's Democratic Republic at Nambak district. Six key variables were identified as determining the financial flows between the subsidy and the insurance schemes and with health providers: population coverage, premium rate, facility contact rate, capitation rate, cost of treatment and changes in administration costs. Negative cross-subsidization was revealed where capitation was used as the payment mechanism and where utilisation rates of the poor were significantly below the non-poor. The same level of access for the poor could have been achieved with a lower Health Equity Fund subsidy if used as a direct reimbursement of user charges by the Health Equity Fund to the provider rather than through the Community Based Health Insurance scheme. Purchasing premiums for the poor under these conditions is more costly than direct reimbursement to the provider for the same level of service delivery. Negative cross-subsidization is a serious risk that must be managed appropriately and the benefits of a larger risk pool (cross-subsidization of the poor) are not evident. Benefits from combined coverage may accrue in the longer term with an expanded base of voluntary payers or when those with subsidized premiums are lifted out of poverty. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Non-canonical regulation of glutathione and trehalose biosynthesis characterizes non-Saccharomyces wine yeasts with poor performance in active dry yeast production

    Directory of Open Access Journals (Sweden)

    Esther Gamero-Sandemetrio

    2018-01-01

    Full Text Available Several yeast species, belonging to Saccharomyces and non-Saccharomyces genera, play fundamental roles during spontaneous must grape fermentation, and recent studies have shown that mixed fermentations, co-inoculated with S. cerevisiae and non-Saccharomyces strains, can improve wine organoleptic properties. During active dry yeast (ADY production, antioxidant systems play an essential role in yeast survival and vitality as both biomass propagation and dehydration cause cellular oxidative stress and negatively affect technological performance. Mechanisms for adaptation and resistance to desiccation have been described for S. cerevisiae, but no data are available on the physiology and oxidative stress response of non-Saccharomyces wine yeasts and their potential impact on ADY production. In this study we analyzed the oxidative stress response in several non-Saccharomyces yeast species by measuring the activity of reactive oxygen species (ROS scavenging enzymes, e.g., catalase and glutathione reductase, accumulation of protective metabolites, e.g., trehalose and reduced glutathione (GSH, and lipid and protein oxidation levels. Our data suggest that non-canonical regulation of glutathione and trehalose biosynthesis could cause poor fermentative performance after ADY production, as it corroborates the corrective effect of antioxidant treatments, during biomass propagation, with both pure chemicals and food-grade argan oil.

  13. Modelling the predictive performance of credit scoring

    Directory of Open Access Journals (Sweden)

    Shi-Wei Shen

    2013-07-01

    Research purpose: The purpose of this empirical paper was to examine the predictive performance of credit scoring systems in Taiwan. Motivation for the study: Corporate lending remains a major business line for financial institutions. However, in light of the recent global financial crises, it has become extremely important for financial institutions to implement rigorous means of assessing clients seeking access to credit facilities. Research design, approach and method: Using a data sample of 10 349 observations drawn between 1992 and 2010, logistic regression models were utilised to examine the predictive performance of credit scoring systems. Main findings: A test of Goodness of fit demonstrated that credit scoring models that incorporated the Taiwan Corporate Credit Risk Index (TCRI, micro- and also macroeconomic variables possessed greater predictive power. This suggests that macroeconomic variables do have explanatory power for default credit risk. Practical/managerial implications: The originality in the study was that three models were developed to predict corporate firms’ defaults based on different microeconomic and macroeconomic factors such as the TCRI, asset growth rates, stock index and gross domestic product. Contribution/value-add: The study utilises different goodness of fits and receiver operator characteristics during the examination of the robustness of the predictive power of these factors.

  14. Pre- and in-therapy predictive score models of adult OSAS patients with poor adherence pattern on nCPAP therapy.

    Science.gov (United States)

    Wang, Yeying; Geater, Alan F; Chai, Yanling; Luo, Jiahong; Niu, Xiaoqun; Hai, Bing; Qin, Jingting; Li, Yongxia

    2015-01-01

    To identify patterns of adherence to nasal continuous positive airway pressure (nCPAP) use in the first 3 months of therapy among newly diagnosed adult patients with obstructive sleep apnea/hypopnea syndrome (OSAS) and their predictors. To develop pretherapy and in-therapy scores to predict adherence pattern. Newly diagnosed adult OSAS patients were consecutively recruited from March to August 2013. Baseline clinical information and measures such as Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), Zung's Self-Rating Depression Scale (SDS), and The Pittsburgh Sleep Quality Index (PSQI) at baseline and at the end of 3rd-week therapy were collected. Twelve weeks' adherence data were collected from the nCPAP memory card, and K-means cluster analysis was used to explore adherence patterns. Predictive scores were developed from the coefficients of cumulative logit models of adherence patterns using variables available at baseline and after 3 weeks of therapy. Performance of the score was validated using 500 bootstrap resamples. Seventy six patients completed a 12-week follow-up. Three patterns were revealed. Patients were identified as developing an adherence pattern that was poor (n=14, mean ± SD, 2.3±0.9 hours per night), moderate (n=19, 5.3±0.6 hours per night), or good (n=43, 6.8±0.3 hours per night). Cumulative logit regression models (good → moderate → poor) revealed independent baseline predictors to be ESS (per unit increase) (OR [95% CI], 0.763 [0.651, 0.893]), SDS (1.461 [1.238, 1.724]), and PSQI (2.261 [1.427, 3.584]); and 3-week therapy predictors to be ESS (0.554 [0.331, 0.926]), PSQI (2.548 [1.454, 4.465]), and the changes (3rd week-baseline data) in ESS (0.459 [0.243, 0.868]), FSS (3.556 [1.788, 7.070]), and PSQI (2.937 [1.273, 6.773]). Two predictive score formulas for poor adherence were developed. The area under the curve (AUC) of the receiver operating characteristics (ROC) curves for baseline and 3-week formulas were 0.989 and 0

  15. High Performance Modeling of Novel Diagnostics Configuration

    Science.gov (United States)

    Smith, Dalton; Gibson, John; Lodes, Rylie; Malcolm, Hayden; Nakamoto, Teagan; Parrack, Kristina; Trujillo, Christopher; Wilde, Zak; Los Alamos Laboratories Q-6 Students Team

    2017-06-01

    A novel diagnostics method to measure the Hayes Electric Effect was tested and verified against computerized models. Where standard PVDF diagnostics utilize piezoelectric materials to measure detonation pressure through strain-induced electrical signals, the PVDF was used in a novel technique by also detecting the detonation's induced electric field. The ALE-3D Hydro Codes predicted the performance by calculating detonation velocities, pressures, and arrival times. These theoretical results then validated the experimental use of the PVDF repurposed to specifically track the Hayes Electric Effect. Los Alamos National Laboratories Q-6.

  16. A Combat Mission Team Performance Model: Development and initial Application

    National Research Council Canada - National Science Library

    Silverman, Denise

    1997-01-01

    ... realistic combat scenarios. We present a conceptual model of team performance measurement in which aircrew coordination, team performance, mission performance and their interrelationships are operationally defined...

  17. A simple probabilistic model of initiation of motion of poorly-sorted granular mixtures subjected to a turbulent flow

    Science.gov (United States)

    Ferreira, Rui M. L.; Ferrer-Boix, Carles; Hassan, Marwan

    2015-04-01

    Initiation of sediment motion is a classic problem of sediment and fluid mechanics that has been studied at wide range of scales. By analysis at channel scale one means the investigation of a reach of a stream, sufficiently large to encompass a large number of sediment grains but sufficiently small not to experience important variations in key hydrodynamic variables. At this scale, and for poorly-sorted hydraulically rough granular beds, existing studies show a wide variation of the value of the critical Shields parameter. Such uncertainty constitutes a problem for engineering studies. To go beyond Shields paradigm for the study of incipient motion at channel scale this problem can be can be cast in probabilistic terms. An empirical probability of entrainment, which will naturally account for size-selective transport, can be calculated at the scale of the bed reach, using a) the probability density functions (PDFs) of the flow velocities {{f}u}(u|{{x}n}) over the bed reach, where u is the flow velocity and xn is the location, b) the PDF of the variability of competent velocities for the entrainment of individual particles, {{f}{{up}}}({{u}p}), where up is the competent velocity, and c) the concept of joint probability of entrainment and grain size. One must first divide the mixture in into several classes M and assign a correspondent frequency p_M. For each class, a conditional PDF of the competent velocity {{f}{{up}}}({{u}p}|M) is obtained, from the PDFs of the parameters that intervene in the model for the entrainment of a single particle: [ {{u}p}/√{g(s-1){{di}}}={{Φ }u}( { {{C}k} },{{{φ}k}},ψ,{{u}p/{di}}{{{ν}(w)}} )) ] where { Ck } is a set of shape parameters that characterize the non-sphericity of the grain, { φk} is a set of angles that describe the orientation of particle axes and its positioning relatively to its neighbours, ψ is the skin friction angle of the particles, {{{u}p}{{d}i}}/{{{ν}(w)}} is a particle Reynolds number, di is the sieving

  18. The COD Model: Simulating Workgroup Performance

    Science.gov (United States)

    Biggiero, Lucio; Sevi, Enrico

    Though the question of the determinants of workgroup performance is one of the most central in organization science, precise theoretical frameworks and formal demonstrations are still missing. In order to fill in this gap the COD agent-based simulation model is here presented and used to study the effects of task interdependence and bounded rationality on workgroup performance. The first relevant finding is an algorithmic demonstration of the ordering of interdependencies in terms of complexity, showing that the parallel mode is the most simplex, followed by the sequential and then by the reciprocal. This result is far from being new in organization science, but what is remarkable is that now it has the strength of an algorithmic demonstration instead of being based on the authoritativeness of some scholar or on some episodic empirical finding. The second important result is that the progressive introduction of realistic limits to agents' rationality dramatically reduces workgroup performance and addresses to a rather interesting result: when agents' rationality is severely bounded simple norms work better than complex norms. The third main finding is that when the complexity of interdependence is high, then the appropriate coordination mechanism is agents' direct and active collaboration, which means teamwork.

  19. Impaired performance on advanced Theory of Mind tasks in children with epilepsy is related to poor communication and increased attention problems.

    Science.gov (United States)

    Lunn, Judith; Lewis, Charlie; Sherlock, Christopher

    2015-02-01

    Children with epilepsy (CWE) have social difficulties that can persist into adulthood, and this could be related to problems with understanding others' thoughts, feelings, and intentions. This study assessed children's ability to interpret and reason on mental and emotional states (Theory of Mind) and examined the relationships between task scores and reports of communication and behavior. Performance of 56 CWE (8-16years of age) with below average IQ (n=17) or an average IQ (n=39) was compared with that of 62 healthy controls with an average IQ (6-16years of age) on cognition, language, and two advanced Theory of Mind (ToM) tasks that required children to attribute mental or emotional states to eye regions and to reason on internal mental states in order to explain behavior. The CWE-below average group were significantly poorer in both ToM tasks compared with controls. The CWE - average group showed a significantly poorer ability to reason on mental states in order to explain behavior, a difference that remained after accounting for lower IQ and language deficits. Poor ToM skills were related to increased communication and attention problems in both CWE groups. There is a risk for atypical social understanding in CWE, even for children with average cognitive function. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Why Does This Learner Perform Poorly on Tests? Using Self-Regulated Learning Theory to Diagnose the Problem and Implement Solutions.

    Science.gov (United States)

    Andrews, Mary A; Kelly, William F; DeZee, Kent J

    2016-11-01

    Learners who underperform on standardized tests are common throughout all levels of medical education and require considerable faculty time and effort to remediate. Current methods for remediating test-taking difficulties are typically not grounded in educational theory or supported by high-quality evidence. A test-taking assessment was developed based on self-regulated learning (SRL) microanalytic assessment and training and used during academic year 2012-2013. This method assesses the SRL subprocesses of strategic planning, self-monitoring, causal attributions, and adaptive inferences during the educational task of answering test questions. The method was designed for one-on-one use by teacher and learner, and for learner self-assessment and practice. At one academic institution, this method was used to categorize learners into struggling test-taker subtypes which correspond to deficiencies in the SRL subprocesses outlined above. A learning plan based on the SRL deficiency was developed for each struggling test-taker subtype. In a small number of internal medicine residents with low in-training examination scores, use of this method yielded improvements in 2013 in-training examination score that doubled the expected improvement based on historical averages. This method is a novel application of SRL theory to a commonly encountered problem in medical education: the learner who performs poorly on tests. Large-scale, multicenter studies of medical learners at a variety of training levels and program types are needed to determine the effectiveness and generalizability of this intervention.

  1. Poor glycaemic control is associated with reduced exercise performance and oxygen economy during cardio-pulmonary exercise testing in people with type 1 diabetes.

    Science.gov (United States)

    Moser, Othmar; Eckstein, Max L; McCarthy, Olivia; Deere, Rachel; Bain, Stephen C; Haahr, Hanne L; Zijlstra, Eric; Bracken, Richard M

    2017-01-01

    To explore the impact of glycaemic control (HbA 1c ) on functional capacity during cardio-pulmonary exercise testing in people with type 1 diabetes. Sixty-four individuals with type 1 diabetes (age: 34 ± 8 years; 13 females, HbA 1c : 7.8 ± 1% (62 ± 13 mmol/mol), duration of diabetes: 17 ± 9 years) performed a cardio-pulmonary cycle ergometer exercise test until volitional exhaustion. Stepwise linear regression was used to explore relationships between HbA 1c and cardio-respiratory data with p ≤ 0.05. Furthermore, participants were divided into quartiles based on HbA 1c levels and cardio-respiratory data were analysed by one-way ANOVA. Multiple regression analysis was performed to explore the relationships between changes in time to exhaustion and cardio-respiratory data. Data were adjusted for confounder. HbA 1c was related to time to exhaustion and oxygen consumption at the power output elicited at the sub-maximal threshold of the heart rate turn point (r = 0.47, R 2  = 0.22, p = 0.03). Significant differences were found at time to exhaustion between Q I vs. Q IV and at oxygen consumption at the power output elicited at the heart rate turn point between Q I vs. Q II and Q I vs. Q IV (p cardio-pulmonary exercise testing. However, exercise training could have the same potential to counteract the influence of poor glycaemic control on functional capacity. Trial registration NCT01704417. Date of registration: October 11, 2012.

  2. The use of the standard exercise test to establish the clinical significance of mild echocardiographic changes in a Thoroughbred poor performer : clinical communication

    Directory of Open Access Journals (Sweden)

    C. Meyer

    2004-06-01

    Full Text Available A 4-year-old Thoroughbred gelding racehorse was referred to the Onderstepoort Veterinary Academic Hospital (OVAH with a history of post-race distress and collapse. In the absence of any obvious abnormalities in the preceding diagnostic work-up, a standard exercise test was performed to determine an underlying cause for the post-race distress reported. In this particular case oxygen desaturation became evident at speeds as slow as 6 m/s, where PO2 was measured at 82.3 mm Hg. Similarly at a blood pH of 7.28, PCO2 had dropped to 30.0mm Hg indicating a combined metabolic acidosis and respiratory alkalosis. The cause of the distress was attributed to a severe hypoxia, with an associated hypocapnoea, confirmed on blood gas analyses, where PO2 levels obtained were as low as 56.6 mm Hg with a mean PCO2 level of 25.4 mm Hg during strenuous exercise. Arterial oxygenation returned to normal immediately after cessation of exercise to 106.44 mm Hg, while the hypocapnoeic alkalosis, PCO2 25.67 mm Hg, persisted until the animal's breathing normalized. The results obtained were indicative of a dynamic cardiac insufficiency present during exercise. The combination of an aortic stenosis and a mitral valve insufficiency may have resulted in a condition similar to that described as high-altitude pulmonary oedema, with respiratory changes and compensation as for acute altitude disease. The results obtained were indicative of a dynamic cardiac insufficiency present during exercise and substantiate the fact that an extensive diagnostic regime may be required to establish a cause for poor performance and that the standard exercise test remains an integral part of this work-up.

  3. A Critical Analysis of Measurement Models of Export Performance

    Directory of Open Access Journals (Sweden)

    Jorge Carneiro

    2007-05-01

    Full Text Available Poor conceptualization of the export performance construct may undermine theory development efforts and may be one of the reasons behind the often conflicting findings in empirical research on the export performance phenomenon. This article reviews the conceptual and empirical literature and proposes a new analytical scheme that may serve as a standard for judging content validity and a guiding yardstick for drawing operational representations of the construct. A critical assessment of some of the most frequently cited measurement frameworks, followed by an analysis of recent (1999-2004 empirical research, leaves no doubt that there are flaws in the conceptualization and operationalization of the performance construct that ought to be addressed. A new measurement model is advanced along with some guidelines which are suggested for its future empirical validation. The new measurement framework allegedly improves on other past efforts in terms of breadth of coverage of the construct’s domain (content validity. It also offers a measurement perspective (with the simultaneous use of both formative and reflective approaches that appears to reflect better the nature of the construct.

  4. Model for measuring complex performance in an aviation environment

    International Nuclear Information System (INIS)

    Hahn, H.A.

    1988-01-01

    An experiment was conducted to identify models of pilot performance through the attainment and analysis of concurrent verbal protocols. Sixteen models were identified. Novice and expert pilots differed with respect to the models they used. Models were correlated to performance, particularly in the case of expert subjects. Models were not correlated to performance shaping factors (i.e. workload). 3 refs., 1 tab

  5. Numerical modeling capabilities to predict repository performance

    International Nuclear Information System (INIS)

    1979-09-01

    This report presents a summary of current numerical modeling capabilities that are applicable to the design and performance evaluation of underground repositories for the storage of nuclear waste. The report includes codes that are available in-house, within Golder Associates and Lawrence Livermore Laboratories; as well as those that are generally available within the industry and universities. The first listing of programs are in-house codes in the subject areas of hydrology, solute transport, thermal and mechanical stress analysis, and structural geology. The second listing of programs are divided by subject into the following categories: site selection, structural geology, mine structural design, mine ventilation, hydrology, and mine design/construction/operation. These programs are not specifically designed for use in the design and evaluation of an underground repository for nuclear waste; but several or most of them may be so used

  6. Dengue human infection model performance parameters.

    Science.gov (United States)

    Endy, Timothy P

    2014-06-15

    Dengue is a global health problem and of concern to travelers and deploying military personnel with development and licensure of an effective tetravalent dengue vaccine a public health priority. The dengue viruses (DENVs) are mosquito-borne flaviviruses transmitted by infected Aedes mosquitoes. Illness manifests across a clinical spectrum with severe disease characterized by intravascular volume depletion and hemorrhage. DENV illness results from a complex interaction of viral properties and host immune responses. Dengue vaccine development efforts are challenged by immunologic complexity, lack of an adequate animal model of disease, absence of an immune correlate of protection, and only partially informative immunogenicity assays. A dengue human infection model (DHIM) will be an essential tool in developing potential dengue vaccines or antivirals. The potential performance parameters needed for a DHIM to support vaccine or antiviral candidates are discussed. © 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.

  7. High-performance phase-field modeling

    KAUST Repository

    Vignal, Philippe

    2015-04-27

    Many processes in engineering and sciences involve the evolution of interfaces. Among the mathematical frameworks developed to model these types of problems, the phase-field method has emerged as a possible solution. Phase-fields nonetheless lead to complex nonlinear, high-order partial differential equations, whose solution poses mathematical and computational challenges. Guaranteeing some of the physical properties of the equations has lead to the development of efficient algorithms and discretizations capable of recovering said properties by construction [2, 5]. This work builds-up on these ideas, and proposes novel discretization strategies that guarantee numerical energy dissipation for both conserved and non-conserved phase-field models. The temporal discretization is based on a novel method which relies on Taylor series and ensures strong energy stability. It is second-order accurate, and can also be rendered linear to speed-up the solution process [4]. The spatial discretization relies on Isogeometric Analysis, a finite element method that possesses the k-refinement technology and enables the generation of high-order, high-continuity basis functions. These basis functions are well suited to handle the high-order operators present in phase-field models. Two-dimensional and three dimensional results of the Allen-Cahn, Cahn-Hilliard, Swift-Hohenberg and phase-field crystal equation will be presented, which corroborate the theoretical findings, and illustrate the robustness of the method. Results related to more challenging examples, namely the Navier-Stokes Cahn-Hilliard and a diusion-reaction Cahn-Hilliard system, will also be presented. The implementation was done in PetIGA and PetIGA-MF, high-performance Isogeometric Analysis frameworks [1, 3], designed to handle non-linear, time-dependent problems.

  8. Solving Enterprise Applications Performance Puzzles Queuing Models to the Rescue

    CERN Document Server

    Grinshpan, Leonid

    2012-01-01

    A groundbreaking scientific approach to solving enterprise applications performance problems Enterprise applications are the information backbone of today's corporations, supporting vital business functions such as operational management, supply chain maintenance, customer relationship administration, business intelligence, accounting, procurement logistics, and more. Acceptable performance of enterprise applications is critical for a company's day-to-day operations as well as for its profitability. Unfortunately, troubleshooting poorly performing enterprise applications has traditionally

  9. DETRA: Model description and evaluation of model performance

    International Nuclear Information System (INIS)

    Suolanen, V.

    1996-01-01

    The computer code DETRA is a generic tool for environmental transfer analyses of radioactive or stable substances. The code has been applied for various purposes, mainly problems related to the biospheric transfer of radionuclides both in safety analyses of disposal of nuclear wastes and in consideration of foodchain exposure pathways in the analyses of off-site consequences of reactor accidents. For each specific application an individually tailored conceptual model can be developed. The biospheric transfer analyses performed by the code are typically carried out for terrestrial, aquatic and food chain applications. 21 refs, 35 figs, 15 tabs

  10. The landscape of GPGPU performance modeling tools

    NARCIS (Netherlands)

    Madougou, S.; Varbanescu, A.; de Laat, C.; van Nieuwpoort, R.

    GPUs are gaining fast adoption as high-performance computing architectures, mainly because of their impressive peak performance. Yet most applications only achieve small fractions of this performance. While both programmers and architects have clear opinions about the causes of this performance gap,

  11. Sensitivity analysis as an aid in modelling and control of (poorly-defined) ecological systems. [closed ecological systems

    Science.gov (United States)

    Hornberger, G. M.; Rastetter, E. B.

    1982-01-01

    A literature review of the use of sensitivity analyses in modelling nonlinear, ill-defined systems, such as ecological interactions is presented. Discussions of previous work, and a proposed scheme for generalized sensitivity analysis applicable to ill-defined systems are included. This scheme considers classes of mathematical models, problem-defining behavior, analysis procedures (especially the use of Monte-Carlo methods), sensitivity ranking of parameters, and extension to control system design.

  12. High expression of HOXA13 correlates with poorly differentiated hepatocellular carcinomas and modulates sorafenib response in in vitro models.

    Science.gov (United States)

    Quagliata, Luca; Quintavalle, Cristina; Lanzafame, Manuela; Matter, Matthias S; Novello, Chiara; di Tommaso, Luca; Pressiani, Tiziana; Rimassa, Lorenza; Tornillo, Luigi; Roncalli, Massimo; Cillo, Clemente; Pallante, Pierlorenzo; Piscuoglio, Salvatore; Ng, Charlotte Ky; Terracciano, Luigi M

    2018-01-01

    Hepatocellular carcinoma (HCC) represents the fifth and ninth cause of mortality among male and female cancer patients, respectively and typically arises on a background of a cirrhotic liver. HCC develops in a multi-step process, often encompassing chronic liver injury, steatosis and cirrhosis eventually leading to the malignant transformation of hepatocytes. Aberrant expression of the class I homeobox gene family (HOX), a group of genes crucial in embryogenesis, has been reported in a variety of malignancies including solid tumors. Among HOX genes, HOXA13 is most overexpressed in HCC and is known to be directly regulated by the long non-coding RNA HOTTIP. In this study, taking advantage of a tissue microarray containing 305 tissue specimens, we found that HOXA13 protein expression increased monotonically from normal liver to cirrhotic liver to HCC and that HOXA13-positive HCCs were preferentially poorly differentiated and had fewer E-cadherin-positive cells. In two independent cohorts, patients with HOXA13-positive HCC had worse overall survival than those with HOXA13-negative HCC. Using HOXA13 immunohistochemistry and HOTTIP RNA in situ hybridization on consecutive sections of 16 resected HCCs, we demonstrated that HOXA13 and HOTTIP were expressed in the same neoplastic hepatocyte populations. Stable overexpression of HOXA13 in liver cancer cell lines resulted in increased colony formation on soft agar and migration potential as well as reduced sensitivity to sorafenib in vitro. Our results provide compelling evidence of a role for HOXA13 in HCC development and highlight for the first time its ability to modulate response to sorafenib.

  13. The Five Key Questions of Human Performance Modeling.

    Science.gov (United States)

    Wu, Changxu

    2018-01-01

    Via building computational (typically mathematical and computer simulation) models, human performance modeling (HPM) quantifies, predicts, and maximizes human performance, human-machine system productivity and safety. This paper describes and summarizes the five key questions of human performance modeling: 1) Why we build models of human performance; 2) What the expectations of a good human performance model are; 3) What the procedures and requirements in building and verifying a human performance model are; 4) How we integrate a human performance model with system design; and 5) What the possible future directions of human performance modeling research are. Recent and classic HPM findings are addressed in the five questions to provide new thinking in HPM's motivations, expectations, procedures, system integration and future directions.

  14. PV Performance Modeling Methods and Practices: Results from the 4th PV Performance Modeling Collaborative Workshop.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-03-01

    In 2014, the IEA PVPS Task 13 added the PVPMC as a formal activity to its technical work plan for 2014-2017. The goal of this activity is to expand the reach of the PVPMC to a broader international audience and help to reduce PV performance modeling uncertainties worldwide. One of the main deliverables of this activity is to host one or more PVPMC workshops outside the US to foster more international participation within this collaborative group. This report reviews the results of the first in a series of these joint IEA PVPS Task 13/PVPMC workshops. The 4th PV Performance Modeling Collaborative Workshop was held in Cologne, Germany at the headquarters of TÜV Rheinland on October 22-23, 2015.

  15. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

  16. Modeling the marketing strategy-performance relationship : towards an hierarchical marketing performance framework

    OpenAIRE

    Huizingh, Eelko K.R.E.; Zengerink, Evelien

    2001-01-01

    Accurate measurement of marketing performance is an important topic for both marketing academics and marketing managers. Many researchers have recognized that marketing performance measurement should go beyond financial measurement. In this paper we propose a conceptual framework that models marketing performance as a sequence of intermediate performance measures ultimately leading to financial performance. This framework, called the Hierarchical Marketing Performance (HMP) framework, starts ...

  17. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    : a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat...

  18. Models and criteria for waste repository performance

    International Nuclear Information System (INIS)

    Smith, C.F.; Cohen, J.J.

    1981-03-01

    A primary objective of the Waste Management Program is to assure that public health is protected. Predictive modeling, to some extent, will play a role in assuring that this objective is met. This paper considers the requirements and limitations of predictive modeling in providing useful inputs to waste management decision making. Criteria development needs and the relation between criteria and models are also discussed

  19. Coenzyme Q10 prevents accelerated cardiac aging in a rat model of poor maternal nutrition and accelerated postnatal growth★

    OpenAIRE

    Tarry-Adkins, Jane L.; Blackmore, Heather L.; Martin-Gronert, Malgorzata S.; Fernandez-Twinn, Denise S.; McConnell, Josie M.; Hargreaves, Iain P.; Giussani, Dino A.; Ozanne, Susan E.

    2013-01-01

    Studies in human and animals have demonstrated that nutritionally induced low birth-weight followed by rapid postnatal growth increases the risk of metabolic syndrome and cardiovascular disease. Although the mechanisms underlying such nutritional programming are not clearly defined, increased oxidative-stress leading to accelerated cellular aging has been proposed to play an important role. Using an established rodent model of low birth-weight and catch-up growth, we show here that post-weani...

  20. [Computer modelling of electroconvulsive treatment and transcranial magnetic stimulation--an explanation of poor efficacy of the magnetic method].

    Science.gov (United States)

    Zyss, Tomasz; Krawczyk, Andrzej; Zieba, Andrzej; Dudek, Dominika; Hese, Robert T; Drzymała, Paweł; Wiak, Sławomir; Sawicki, Bartosz; Starzyński, Jacek; Szmurło, Robert; Wincenciak, Stanisław

    2010-01-01

    With help of informatics technology it is possible to simulate various physiological processes in virtual models of biological structures. In a created realistic model of the human head we made some comparative investigations over physical phenomena accompanying the electroconvulsive treatment ECT and transcranial magnetic stimulation TMS--two methods with confirmed (ECT) or presumable (TMS) antidepressant efficacy. The present investigations are a continuation of the earlier conducted study in the simple spherical model of the head. Investigations confirmed, that magnetic stimulation TMS generates a considerably weaker current flow in the brain than it is present in electroconvulsive technique. Applying of such weak stimulation in modus,,at haphazard", i.e. on the brain area which does not need to be metabolically disturbed in this patient--cannot cause an antidepressant effect at all. The results of the investigations explain not only the safety of the magnetic method, but the weak effectiveness of this method. The authors propose some methods for improvement of TMS efficacy.

  1. Poor stimulus discriminability as a common neuropsychological deficit between ADHD and reading ability in young children: a moderated mediation model.

    Science.gov (United States)

    Lúcio, P S; Salum, G A; Rohde, L A; Swardfager, W; Gadelha, A; Vandekerckhove, J; Pan, P M; Polanczyk, G V; do Rosário, M C; Jackowski, A P; Mari, J J; Cogo-Moreira, H

    2017-01-01

    Attention deficit hyperactivity disorder (ADHD) is frequently associated with poorer reading ability; however, the specific neuropsychological domains linking this co-occurrence remain unclear. This study evaluates information-processing characteristics as possible neuropsychological links between ADHD symptoms and RA in a community-based sample of children and early adolescents with normal IQ (⩾70). The participants (n = 1857, aged 6-15 years, 47% female) were evaluated for reading ability (reading single words aloud) and information processing [stimulus discriminability in the two-choice reaction-time task estimated using diffusion models]. ADHD symptoms were ascertained through informant (parent) report using the Development and Well-Being Assessment (DAWBA). Verbal working memory (VWM; digit span backwards), visuospatial working memory (VSWM, Corsi Blocks backwards), sex, socioeconomic status, and IQ were included as covariates. In a moderated mediation model, stimulus discriminability mediated the effect of ADHD on reading ability. This indirect effect was moderated by age such that a larger effect was seen among younger children. The findings support the hypothesis that ADHD and reading ability are linked among young children via a neuropsychological deficit related to stimulus discriminability. Early interventions targeting stimulus discriminability might improve symptoms of inattention/hyperactivity and reading ability.

  2. On the necessity of composition-dependent low-temperature opacity in models of metal-poor asymptotic giant branch stars

    Energy Technology Data Exchange (ETDEWEB)

    Constantino, Thomas; Campbell, Simon; Lattanzio, John [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Victoria 3800 (Australia); Gil-Pons, Pilar, E-mail: thomas.constantino@monash.edu [Department of Applied Physics, Polytechnic University of Catalonia, 08860 Barcelona (Spain)

    2014-03-20

    The vital importance of composition-dependent low-temperature opacity in low-mass (M ≤ 3 M {sub ☉}) asymptotic giant branch (AGB) stellar models of metallicity Z ≥ 0.001 has recently been demonstrated. Its significance to more metal-poor, intermediate-mass (M ≥ 2.5 M {sub ☉}) models has yet to be investigated. We show that its inclusion in lower-metallicity models ([Fe/H] ≤–2) is essential and that there exists no threshold metallicity below which composition-dependent molecular opacity may be neglected. We find it to be crucial in all intermediate-mass models investigated ([Fe/H] ≤–2 and 2.5 ≤ M/M {sub ☉} ≤ 5), because of the evolution of the surface chemistry, including the orders of magnitude increase in the abundance of molecule-forming species. Its effect on these models mirrors that previously reported for higher-metallicity models—increase in radius, decrease in T {sub eff}, faster mass loss, shorter thermally pulsing AGB lifetime, reduced enrichment in third dredge-up products (by a factor of 3-10), and an increase in the mass limit for hot bottom burning. We show that the evolution of low-metallicity models with composition-dependent low-temperature opacity is relatively independent of initial metal abundance because its contribution to the opacity is far outweighed by changes resulting from dredge-up. Our results imply a significant reduction in the expected number of nitrogen-enhanced metal-poor stars, which may help explain their observed paucity. We note that these findings are partially a product of the macrophysics adopted in our models, in particular, the Vassiliadis and Wood mass loss rate which is strongly dependent on radius.

  3. Models and criteria for LLW disposal performance

    International Nuclear Information System (INIS)

    Smith, C.F.; Cohen, J.J.

    1980-12-01

    A primary objective of the Low Level Waste (LLW) Management Program is to assure that public health is protected. Predictive modeling, to some extent, will play a role in meeting this objective. This paper considers the requirements and limitations of predictive modeling in providing useful inputs to waste mangement decision making. In addition, criteria development needs and the relation between criteria and models are discussed

  4. Models and criteria for LLW disposal performance

    International Nuclear Information System (INIS)

    Smith, C.F.; Cohen, J.J.

    1980-01-01

    A primary objective of the Low Level Waste (LLW) Management Program is to assure that public health is protected. Predictive modeling, to some extent, will play a role in meeting this objective. This paper considers the requirements and limitations of predictive modeling in providing useful inputs to waste management decision making. In addition, criteria development needs and the relation between criteria and models are discussed

  5. Model Performance Evaluation and Scenario Analysis (MPESA) Tutorial

    Science.gov (United States)

    The model performance evaluation consists of metrics and model diagnostics. These metrics provides modelers with statistical goodness-of-fit measures that capture magnitude only, sequence only, and combined magnitude and sequence errors.

  6. Modelling Flexible Pavement Response and Performance

    DEFF Research Database (Denmark)

    Ullidtz, Per

    This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods.......This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods....

  7. HANDOVER MANAGEABILITY AND PERFORMANCE MODELING IN

    African Journals Online (AJOL)

    SOFTLINKS DIGITAL

    This work develops a model for interpreting implementation progress. The proposed progress monitoring model uses existing implementation artefact metrics, tries .... determine implementation velocity. As noted by McConnell [28] this velocity increases at the beginning and decreases near the end. A formal implementation.

  8. Modeling, simulation and performance evaluation of parabolic ...

    African Journals Online (AJOL)

    Model of a parabolic trough power plant, taking into consideration the different losses associated with collection of the solar irradiance and thermal losses is presented. MATLAB software is employed to model the power plant at reference state points. The code is then used to find the different reference values which are ...

  9. Detailed Performance Model for Photovoltaic Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tian, H.; Mancilla-David, F.; Ellis, K.; Muljadi, E.; Jenkins, P.

    2012-07-01

    This paper presents a modified current-voltage relationship for the single diode model. The single-diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell. The modification presented in this paper accounts for both parallel and series connections in an array.

  10. MultiComponent Exercise and theRApeutic lifeStyle (CERgAS) intervention to improve physical performance and maintain independent living among urban poor older people--a cluster randomised controlled trial.

    Science.gov (United States)

    Loh, Debbie Ann; Hairi, Noran Naqiah; Choo, Wan Yuen; Mohd Hairi, Farizah; Peramalah, Devi; Kandiben, Shathanapriya; Lee, Pek Ling; Gani, Norlissa; Madzlan, Mohamed Faris; Abd Hamid, Mohd Alif Idham; Akram, Zohaib; Chu, Ai Sean; Bulgiba, Awang; Cumming, Robert G

    2015-02-11

    The ability of older people to function independently is crucial as physical disability and functional limitation have profound impacts on health. Interventions that either delay the onset of frailty or attenuate its severity potentially have cascading benefits for older people, their families and society. This study aims to develop and evaluate the effectiveness of a multiComponent Exercise and theRApeutic lifeStyle (CERgAS) intervention program targeted at improving physical performance and maintaining independent living as compared to general health education among older people in an urban poor setting in Malaysia. This cluster randomised controlled trial will be a 6-week community-based intervention programme for older people aged 60 years and above from urban poor settings. A minimum of 164 eligible participants will be recruited from 8 clusters (low-cost public subsidised flats) and randomised to the intervention and control arm. This study will be underpinned by the Health Belief Model with an emphasis towards self-efficacy. The intervention will comprise multicomponent group exercise sessions, nutrition education, oral care education and on-going support and counselling. These will be complemented with a kit containing practical tips on exercise, nutrition and oral care after each session. Data will be collected over four time points; at baseline, immediately post-intervention, 3-months and 6-months follow-up. Findings from this trial will potentially provide valuable evidence to improve physical function and maintain independence among older people from low-resource settings. This will inform health policies and identify locally acceptable strategies to promote healthy aging, prevent and delay functional decline among older Malaysian adults. ISRCTN22749696.

  11. In vitro evaluation of sustained released matrix tablets containing ibuprofen: a model poorly water-soluble drug

    Directory of Open Access Journals (Sweden)

    Wendy Leticia Guerra-Ponce

    Full Text Available ABSTRACT A matrix system was developed that releases ibuprofen (IB over a 12-hour period and the influence of the polymer type and concentration on the release rate of the drug was evaluated. Tablets containing different concentrations of Carbopol (CP, hydroxypropyl methylcellulose (HPMC, or ethyl cellulose (EC were prepared using direct compression and the drug content, content uniformity, hardness, friability, dissolution performance, and in vitro release kinetics were examined. Formulated tablets were found to be within acceptable limits for physical and chemical parameters. The release kinetics of the Carbopol(r971P 8% formulation showed the best linearity (r 2 =0.977 in fitting zero-order kinetics, suggesting the release rate was time independent. The drug release from tablets containing 8% CP was extended over approximately 18 hours and the release kinetics were nearly linear, suggesting that this system has the potential to maintain constant plasma drug concentrations over 12 hours, which could reduce the frequency of administration and the occurrence of adverse effects associated with repeated administration of conventional IB tablets.

  12. Model for Agile Software Development Performance Monitoring

    OpenAIRE

    Žabkar, Nataša

    2013-01-01

    Agile methodologies have been in use for more than ten years and during this time they proved to be efficient, even though number of empirical research is scarce, especially regarding agile software development performance monitoring. The most popular agile framework Scrum is using only one measure of performance: the amount of work remaining for implementation of User Story from the Product Backlog or for implementation of Task from the Sprint Backlog. In time the need for additional me...

  13. Modeling and optimization of LCD optical performance

    CERN Document Server

    Yakovlev, Dmitry A; Kwok, Hoi-Sing

    2015-01-01

    The aim of this book is to present the theoretical foundations of modeling the optical characteristics of liquid crystal displays, critically reviewing modern modeling methods and examining areas of applicability. The modern matrix formalisms of optics of anisotropic stratified media, most convenient for solving problems of numerical modeling and optimization of LCD, will be considered in detail. The benefits of combined use of the matrix methods will be shown, which generally provides the best compromise between physical adequacy and accuracy with computational efficiency and optimization fac

  14. A unified tool for performance modelling and prediction

    International Nuclear Information System (INIS)

    Gilmore, Stephen; Kloul, Leila

    2005-01-01

    We describe a novel performability modelling approach, which facilitates the efficient solution of performance models extracted from high-level descriptions of systems. The notation which we use for our high-level designs is the Unified Modelling Language (UML) graphical modelling language. The technology which provides the efficient representation capability for the underlying performance model is the multi-terminal binary decision diagram (MTBDD)-based PRISM probabilistic model checker. The UML models are compiled through an intermediate language, the stochastic process algebra PEPA, before translation into MTBDDs for solution. We illustrate our approach on a real-world analysis problem from the domain of mobile telephony

  15. Integrated thermodynamic model for ignition target performance

    Directory of Open Access Journals (Sweden)

    Springer P.T.

    2013-11-01

    Full Text Available We have derived a 3-dimensional synthetic model for NIF implosion conditions, by predicting and optimizing fits to a broad set of x-ray and nuclear diagnostics obtained on each shot. By matching x-ray images, burn width, neutron time-of-flight ion temperature, yield, and fuel ρr, we obtain nearly unique constraints on conditions in the hotspot and fuel in a model that is entirely consistent with the observables. This model allows us to determine hotspot density, pressure, areal density (ρr, total energy, and other ignition-relevant parameters not available from any single diagnostic. This article describes the model and its application to National Ignition Facility (NIF tritium–hydrogen–deuterium (THD and DT implosion data, and provides an explanation for the large yield and ρr degradation compared to numerical code predictions.

  16. Mathematical Modeling of Circadian/Performance Countermeasures

    Data.gov (United States)

    National Aeronautics and Space Administration — We developed and refined our current mathematical model of circadian rhythms to incorporate melatonin as a marker rhythm. We used an existing physiologically based...

  17. Hydrologic Evaluation of Landfill Performance (HELP) Model

    Science.gov (United States)

    The program models rainfall, runoff, infiltration, and other water pathways to estimate how much water builds up above each landfill liner. It can incorporate data on vegetation, soil types, geosynthetic materials, initial moisture conditions, slopes, etc.

  18. Evaluating Models of Human Performance: Safety-Critical Systems Applications

    Science.gov (United States)

    Feary, Michael S.

    2012-01-01

    This presentation is part of panel discussion on Evaluating Models of Human Performance. The purpose of this panel is to discuss the increasing use of models in the world today and specifically focus on how to describe and evaluate models of human performance. My presentation will focus on discussions of generating distributions of performance, and the evaluation of different strategies for humans performing tasks with mixed initiative (Human-Automation) systems. I will also discuss issues with how to provide Human Performance modeling data to support decisions on acceptability and tradeoffs in the design of safety critical systems. I will conclude with challenges for the future.

  19. Comparison of performance of simulation models for floor heating

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Svendsen, Svend

    2005-01-01

    This paper describes the comparison of performance of simulation models for floor heating with different level of detail in the modelling process. The models are compared in an otherwise identical simulation model containing room model, walls, windows, ceiling and ventilation system. By exchanging...

  20. Developing an Energy Performance Modeling Startup Kit

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2012-10-01

    In 2011, the NAHB Research Center began assessing the needs and motivations of residential remodelers regarding energy performance remodeling. This report outlines: the current remodeling industry and the role of energy efficiency; gaps and barriers to adding energy efficiency into remodeling; and support needs of professional remodelers to increase sales and projects involving improving home energy efficiency.

  1. Modeling vibrato and portamento in music performance

    NARCIS (Netherlands)

    Desain, P.W.M.; Honing, H.J.

    1999-01-01

    Research in the psychology of music dealing with expression is often concerned with the discrete aspects of music performance, and mainly concentrates on the study of piano music (partly because of the ease with which piano music can be reduced to discrete note events). However, on other

  2. WirelessHART modeling and performance evaluation

    NARCIS (Netherlands)

    Remke, Anne Katharina Ingrid; Wu, Xian

    2013-01-01

    In process industries wired supervisory and control networks are more and more replaced by wireless systems. Wireless communication inevitably introduces time delays and message losses, which may degrade the system reliability and performance. WirelessHART, as the first international standard for

  3. Technologies to better serve the millions of diabetic patients: a holistic, interactive and persuasive ICT model to facilitate self care, in extremely poor rural zones of Central America.

    Science.gov (United States)

    Vargas-Lombardo, Miguel; Jipsion, Armando; Vejarano, Rafael; Camargo, Ismael; Alvarez, Humberto; Mora, Elena Villalba; Ruíz, Ernestina Menasalva

    2012-04-01

    Health indicators express remarkable gaps between health systems at a world-wide level. Countries of the entire world are overflowed by the need of new strategies, methodologies and technologies to better serve the millions of patients, who demand better medical attention. The present archaic and ephemerally systematized systems widen the gap even more than the quality of medical services that should be provided for the millions of diabetic patients. It is therefore necessary to develop highly familiar environments with diabetic patients and their care needs. A Holistic, Interactive and Persuasive ICT model to facilitate self care of patients with diabetes (hIPAPD), is proposed as an innovative technological development in Panama to health optimized treatment for diabetic patients. Three health centers located in the District of Aguadulce, Province of Cocle, located on Panama's Pacific Coast, were selected to validate the model; the area presents extremely poor population, mostly with one daily meal, without any health insurance and with a high illiteracy rate. A series of experiences in the application and validation process are presented and analyzed in order to confirm the application, value and contribution of ICTs in health care in poor regions of Central America.

  4. Non-local thermodynamic equilibrium stellar spectroscopy with 1D and 3D models - II. Chemical properties of the Galactic metal-poor disk and the halo

    DEFF Research Database (Denmark)

    Bergemann, Maria; Collet, Remo; Schönrich, Ralph

    2016-01-01

    We have analysed high-resolution spectra of 328 stars and derived Mg abundances using non-local thermodynamic equilibrium (NLTE) spectral line formation calculations and plane-parallel model stellar atmospheres derived from the mean stratification of 3D hydrodynamical surface convection simulations...... of late-type stars. The distribution of Mg abundances in the Galactic disk is analysed from the perspective of Galactic chemical evolution. We find that the trend of [Mg/Fe] shows a mild decline with decreasing metallicity below [Fe/H]~-1.2 and that a significant fraction of low-metallicity stars have [Mg....../Fe] ratios close to solar even at [Fe/H] ~ -2. This is at variance with results of classical abundance analyses based on local thermodynamic equilibrium (LTE) and 1D model stellar atmospheres, which argue for a constant elevated [Mg/Fe] in metal-poor stars of the Galactic thick disk and halo....

  5. Neuro-fuzzy model for evaluating the performance of processes ...

    Indian Academy of Sciences (India)

    In this work an Adaptive Neuro-Fuzzy Inference System (ANFIS) was used to model the periodic performance of some multi-input single-output (MISO) processes, namely: brewery operations (case study 1) and soap production (case study 2) processes. Two ANFIS models were developed to model the performance of the ...

  6. Persistence Modeling for Assessing Marketing Strategy Performance

    NARCIS (Netherlands)

    M.G. Dekimpe (Marnik); D.M. Hanssens (Dominique)

    2003-01-01

    textabstractThe question of long-run market response lies at the heart of any marketing strategy that tries to create a sustainable competitive advantage for the firm or brand. A key challenge, however, is that only short-run results of marketing actions are readily observable. Persistence modeling

  7. Some useful characteristics of performance models

    International Nuclear Information System (INIS)

    Worledge, D.H.

    1985-01-01

    This paper examines the demands placed upon models of human cognitive decision processes in application to Probabilistic Risk Assessment. Successful models, for this purpose, should, 1) be based on proven or plausible psychological knowledge, e.g., Rasmussen's mental schematic, 2) incorporate opportunities for slips, 3) take account of the recursive nature, in time, of corrections to mistaken actions, and 4) depend on the crew's predominant mental states that accompany such recursions. The latter is equivalent to an explicit coupling between input and output of Rasmussen's mental schematic. A family of such models is proposed with observable rate processes mediating the (conscious) mental states involved. It is expected that the cumulative probability distributions corresponding to the individual rate processes can be identified with probability-time correlations of the HCR Human Cognitive Reliability type discussed elsewhere in this session. The functional forms of the conditional rates are intuitively shown to have simple characteristics that lead to a strongly recursive stochastic process with significant predictive capability. Models of the type proposed have few parts and form a representation that is intentionally far short of a fully transparent exposition of the mental process in order to avoid making impossible demands on data

  8. Evaluating Performances of Traffic Noise Models | Oyedepo ...

    African Journals Online (AJOL)

    Traffic noise in decibel dB(A) were measured at six locations using 407780A Integrating Sound Level Meter, while spot speed and traffic volume were collected with cine-camera. The predicted sound exposure level (SEL) was evaluated using Burgess, British and FWHA model. The average noise level obtained are 77.64 ...

  9. HANDOVER MANAGEABILITY AND PERFORMANCE MODELING IN

    African Journals Online (AJOL)

    SOFTLINKS DIGITAL

    situations. Library Management Design Using Use. Case. To model software using object oriented design, a case study of Bingham University. Library Management System is used. Software is developed to automate the Bingham. University manual Library. The system will be stand alone and will be designed with the.

  10. Sustaining Team Performance: A Systems Model\\

    Science.gov (United States)

    1979-07-31

    a " forgetting curve ." Three cases were tested and retested under four different research schedules. A description c;’ the test cases follows. III-11...available to show fluctuation in Ph due to unit yearly training cycle. Another real-world military example of the classical forgetting curve is found in the...no practice between the acquisition and subsequent test of performance. The classical forgetting curve is believed to apply. The shape of curve depends

  11. Modelling swimming hydrodynamics to enhance performance

    OpenAIRE

    Marinho, D.A.; Rouboa, A.; Barbosa, Tiago M.; Silva, A.J.

    2010-01-01

    Swimming assessment is one of the most complex but outstanding and fascinating topics in biomechanics. Computational fluid dynamics (CFD) methodology is one of the different methods that have been applied in swimming research to observe and understand water movements around the human body and its application to improve swimming performance. CFD has been applied attempting to understand deeply the biomechanical basis of swimming. Several studies have been conducted willing to analy...

  12. [Poor insight and psychosis].

    Science.gov (United States)

    Giotakos, O

    2017-01-01

    A variety of phenomena might be considered as reflecting impaired insight in psychosis, like failure to recognize signs, symptoms or disease, failure to derive appropriate cognitive representations, despite recognition of the disease, and misattribution of the source or cause of the disease. The unawareness of tardive dyskinesia symptoms in schizophrenic patients points that self-awareness deficits in schizophrenia may be domain specific. Poor insight is an independent phenomenological and a prevalent feature in psychotic disorders in general, and in schizophrenia in particular, but we don't know yet if delusions in schizophrenia are the result of an entirely normal attempt to account for abnormal perceptual experiences or a product of abnormal experience but of normal reasoning. The theoretical approaches regarding impaired insight include the disturbed perceptual input, the impaired linkage between thought and emotion and the breakdown of the process of self-monitoring and error checking. The inability to distinguish between internally and externally generated mental events has been described by the metarepresentation theory. This theory includes the awareness of ones' goals, which leads to disorders of willed action, the awareness of intention, which leads to movement disorders, and the awareness of intentions of others, which leads to paranoid delusions. The theory of metarepresentation implies mainly output mechanisms, like the frontal cortex, while the input mechanism implies posterior brain systems, including the parietal lobe. There are many similarities between the disturbances of awareness seen in schizophrenia and those seen as a result of known neurological impairment. Neuropsychological models of impaired insight typically attribute the disturbance to any of a variety of core deficits in the processing of information. In this respect, lack of insight is on conceptual par with alogia, apraxia or aphasia in reflecting disturbed cognitive processing. In

  13. An Empirical Study of a Solo Performance Assessment Model

    Science.gov (United States)

    Russell, Brian E.

    2015-01-01

    The purpose of this study was to test a hypothesized model of solo music performance assessment. Specifically, this study investigates the influence of technique and musical expression on perceptions of overall performance quality. The Aural Musical Performance Quality (AMPQ) measure was created to measure overall performance quality, technique,…

  14. Poor Trail Making Test Performance Is Directly Associated with Altered Dual Task Prioritization in the Elderly ? Baseline Results from the TREND Study

    OpenAIRE

    Hobert, Markus A.; Niebler, Raphael; Meyer, Sinja I.; Brockmann, Kathrin; Becker, Clemens; Huber, Heiko; Gaenslen, Alexandra; Godau, Jana; Eschweiler, Gerhard W.; Berg, Daniela; Maetzler, Walter

    2011-01-01

    BACKGROUND: Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance--which specifically measures cognitive flexibility and working memory--and dual task costs, a measure of prioritiz...

  15. Developing an Energy Performance Modeling Startup Kit

    Energy Technology Data Exchange (ETDEWEB)

    Wood, A.

    2012-10-01

    In 2011, the NAHB Research Center began the first part of the multi-year effort by assessing the needs and motivations of residential remodelers regarding energy performance remodeling. The scope is multifaceted - all perspectives will be sought related to remodeling firms ranging in size from small-scale, sole proprietor to national. This will allow the Research Center to gain a deeper understanding of the remodeling and energy retrofit business and the needs of contractors when offering energy upgrade services. To determine the gaps and the motivation for energy performance remodeling, the NAHB Research Center conducted (1) an initial series of focus groups with remodelers at the 2011 International Builders' Show, (2) a second series of focus groups with remodelers at the NAHB Research Center in conjunction with the NAHB Spring Board meeting in DC, and (3) quantitative market research with remodelers based on the findings from the focus groups. The goal was threefold, to: Understand the current remodeling industry and the role of energy efficiency; Identify the gaps and barriers to adding energy efficiency into remodeling; and Quantify and prioritize the support needs of professional remodelers to increase sales and projects involving improving home energy efficiency. This report outlines all three of these tasks with remodelers.

  16. Modeling the Mechanical Performance of Die Casting Dies

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2004-02-27

    The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

  17. Modeling the marketing strategy-performance relationship : towards an hierarchical marketing performance framework

    NARCIS (Netherlands)

    Huizingh, Eelko K.R.E.; Zengerink, Evelien

    2001-01-01

    Accurate measurement of marketing performance is an important topic for both marketing academics and marketing managers. Many researchers have recognized that marketing performance measurement should go beyond financial measurement. In this paper we propose a conceptual framework that models

  18. Modeling and analysis to quantify MSE wall behavior and performance.

    Science.gov (United States)

    2009-08-01

    To better understand potential sources of adverse performance of mechanically stabilized earth (MSE) walls, a suite of analytical models was studied using the computer program FLAC, a numerical modeling computer program widely used in geotechnical en...

  19. Coenzyme Q10 prevents hepatic fibrosis, inflammation, and oxidative stress in a male rat model of poor maternal nutrition and accelerated postnatal growth1

    Science.gov (United States)

    Tarry-Adkins, Jane L; Fernandez-Twinn, Denise S; Hargreaves, Iain P; Neergheen, Viruna; Aiken, Catherine E; Martin-Gronert, Malgorzata S; McConnell, Josie M; Ozanne, Susan E

    2016-01-01

    Background: It is well established that low birth weight and accelerated postnatal growth increase the risk of liver dysfunction in later life. However, molecular mechanisms underlying such developmental programming are not well characterized, and potential intervention strategies are poorly defined. Objectives: We tested the hypotheses that poor maternal nutrition and accelerated postnatal growth would lead to increased hepatic fibrosis (a pathological marker of liver dysfunction) and that postnatal supplementation with the antioxidant coenzyme Q10 (CoQ10) would prevent this programmed phenotype. Design: A rat model of maternal protein restriction was used to generate low-birth-weight offspring that underwent accelerated postnatal growth (termed “recuperated”). These were compared with control rats. Offspring were weaned onto standard feed pellets with or without dietary CoQ10 (1 mg/kg body weight per day) supplementation. At 12 mo, hepatic fibrosis, indexes of inflammation, oxidative stress, and insulin signaling were measured by histology, Western blot, ELISA, and reverse transcriptase–polymerase chain reaction. Results: Hepatic collagen deposition (diameter of deposit) was greater in recuperated offspring (mean ± SEM: 12 ± 2 μm) than in controls (5 ± 0.5 μm) (P supplementation increased (P adulthood, which was associated with higher indexes of oxidative stress and inflammation and hyperinsulinemia. CoQ10 supplementation prevented liver fibrosis accompanied by downregulation of oxidative stress, inflammation, and hyperinsulinemia. PMID:26718412

  20. Coenzyme Q10 prevents hepatic fibrosis, inflammation, and oxidative stress in a male rat model of poor maternal nutrition and accelerated postnatal growth.

    Science.gov (United States)

    Tarry-Adkins, Jane L; Fernandez-Twinn, Denise S; Hargreaves, Iain P; Neergheen, Viruna; Aiken, Catherine E; Martin-Gronert, Malgorzata S; McConnell, Josie M; Ozanne, Susan E

    2016-02-01

    It is well established that low birth weight and accelerated postnatal growth increase the risk of liver dysfunction in later life. However, molecular mechanisms underlying such developmental programming are not well characterized, and potential intervention strategies are poorly defined. We tested the hypotheses that poor maternal nutrition and accelerated postnatal growth would lead to increased hepatic fibrosis (a pathological marker of liver dysfunction) and that postnatal supplementation with the antioxidant coenzyme Q10 (CoQ10) would prevent this programmed phenotype. A rat model of maternal protein restriction was used to generate low-birth-weight offspring that underwent accelerated postnatal growth (termed "recuperated"). These were compared with control rats. Offspring were weaned onto standard feed pellets with or without dietary CoQ10 (1 mg/kg body weight per day) supplementation. At 12 mo, hepatic fibrosis, indexes of inflammation, oxidative stress, and insulin signaling were measured by histology, Western blot, ELISA, and reverse transcriptase-polymerase chain reaction. Hepatic collagen deposition (diameter of deposit) was greater in recuperated offspring (mean ± SEM: 12 ± 2 μm) than in controls (5 ± 0.5 μm) (P supplementation increased (P adulthood, which was associated with higher indexes of oxidative stress and inflammation and hyperinsulinemia. CoQ10 supplementation prevented liver fibrosis accompanied by downregulation of oxidative stress, inflammation, and hyperinsulinemia.

  1. Characterization uncertainty and its effects on models and performance

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, C.A.; Treadway, A.H.

    1991-01-01

    Geostatistical simulation is being used to develop multiple geologic models of rock properties at the proposed Yucca Mountain repository site. Because each replicate model contains the same known information, and is thus essentially indistinguishable statistically from others, the differences between models may be thought of as representing the uncertainty in the site description. The variability among performance measures, such as ground water travel time, calculated using these replicate models therefore quantifies the uncertainty in performance that arises from uncertainty in site characterization.

  2. Metrics for evaluating performance and uncertainty of Bayesian network models

    Science.gov (United States)

    Bruce G. Marcot

    2012-01-01

    This paper presents a selected set of existing and new metrics for gauging Bayesian network model performance and uncertainty. Selected existing and new metrics are discussed for conducting model sensitivity analysis (variance reduction, entropy reduction, case file simulation); evaluating scenarios (influence analysis); depicting model complexity (numbers of model...

  3. Modeling and Performance Analysis of Manufacturing Systems in ...

    African Journals Online (AJOL)

    This study deals with modeling and performance analysis of footwear manufacturing using arena simulation modeling software. It was investigated that modeling and simulation is a potential tool for modeling and analysis of manufacturing assembly lines like footwear manufacturing because it allows the researcher to ...

  4. Identifying the connective strength between model parameters and performance criteria

    Directory of Open Access Journals (Sweden)

    B. Guse

    2017-11-01

    Full Text Available In hydrological models, parameters are used to represent the time-invariant characteristics of catchments and to capture different aspects of hydrological response. Hence, model parameters need to be identified based on their role in controlling the hydrological behaviour. For the identification of meaningful parameter values, multiple and complementary performance criteria are used that compare modelled and measured discharge time series. The reliability of the identification of hydrologically meaningful model parameter values depends on how distinctly a model parameter can be assigned to one of the performance criteria. To investigate this, we introduce the new concept of connective strength between model parameters and performance criteria. The connective strength assesses the intensity in the interrelationship between model parameters and performance criteria in a bijective way. In our analysis of connective strength, model simulations are carried out based on a latin hypercube sampling. Ten performance criteria including Nash–Sutcliffe efficiency (NSE, Kling–Gupta efficiency (KGE and its three components (alpha, beta and r as well as RSR (the ratio of the root mean square error to the standard deviation for different segments of the flow duration curve (FDC are calculated. With a joint analysis of two regression tree (RT approaches, we derive how a model parameter is connected to different performance criteria. At first, RTs are constructed using each performance criterion as the target variable to detect the most relevant model parameters for each performance criterion. Secondly, RTs are constructed using each parameter as the target variable to detect which performance criteria are impacted by changes in the values of one distinct model parameter. Based on this, appropriate performance criteria are identified for each model parameter. In this study, a high bijective connective strength between model parameters and performance criteria

  5. [Rhinitis and asthma as a cause of absenteeism and poor work/school performance in a population from Latin-American tropic].

    Science.gov (United States)

    Sánchez, Jorge; Estarita, Javier; Salemi, Carolina

    2016-01-01

    Asthma and rhinitis are the most frequent chronic respiratory diseases. Their high impact is associated with the loss of working days, as well as a decrease in academic performance. To assess and compare the impact of rhinitis and asthma as causes of absenteeism and low work performance in a population of children and adults. A cross sectional study was performed in 10 schools of two cities in Colombia. The student population between 6 to 17 years, as well as the faculty staff over 18 were invited to participate. All of the participants filled a questionnaire assessing parameters related to clinical background, and a review of scores in Math and Spanish, curriculum vitae and number of missed day during the last academic period completed was performed. A total of 1,413 participants were enrolled. The frequency of asthma and/or rhinitis was 36%, there was a greater frequency of absenteeism in the population of children with respiratory symptoms (2.8 vs 1.2 days/year/patient, pabsenteeism and an improved performance. Both rhinitis and asthma are associated with lower performance in children and adults and absenteeism in the school; however, adequate treatment may improve clinical control and reduce backlash against job performance.

  6. Performance Measurement Model A TarBase model with ...

    Indian Academy of Sciences (India)

    rohit

    Cost. G=Gamma. CV=Cross Validation. MCC=Matthew Correlation Coefficient. Test 1: C G CV Accuracy TP TN FP FN ... Conclusion: Without considering the MirTif negative dataset for training Model A and B classifiers, our Model A and B ...

  7. Can the Myocardial Performance Index Be Used as a New Predictive Factor for a Poor Prognosis in Fetuses With Idiopathic Polyhydramnios?

    Science.gov (United States)

    Gezer, Cenk; Ekin, Atalay; Ozeren, Mehmet; Taner, Cuneyt Eftal; Mat, Emre; Solmaz, Ulas

    2016-12-01

    The purpose of this study was to determine whether there are any changes in cardiac function in fetuses with idiopathic polyhydramnios and also to evaluate the value of the myocardial performance index for prediction of adverse perinatal outcomes. A prospective case-control study was conducted with a total of 134 fetuses between 24 and 40 weeks' gestation. Polyhydramnios was defined as an amniotic fluid index of greater than 24 cm. Seventy-three fetuses of healthy mothers were assigned as the control group whereas 36 fetuses with an amniotic fluid index of 24 to 34 cm constituted the nonsevere polyhydramnios group, and 31 fetuses with an amniotic fluid index of 35 cm or greater constituted the severe polyhydramnios group. Fetal echocardiography was performed to compare cardiac function parameters among groups. To determine which perinatal outcomes were independently associated with an increased myocardial performance index, a multivariate logistic regression analysis was performed. The myocardial performance index was significantly higher in polyhydramnios groups compared with controls (P polyhydramnios, the myocardial performance index was significantly higher in severe polyhydramnios compared with nonsevere polyhydramnios (P = .003). An increased myocardial performance index in polyhydramnios was independently associated with nonreassuring fetal status (odds ratio, 2.12; 95% confidence interval, 1.41-4.53; P = .005), emergency cesarean delivery (odds ratio, 1.54; 95% confidence interval, 1.12-2.37; P= .025), and respiratory distress syndrome (odds ratio, 1.79; 95% confidence interval, 1.21-3.87; P = .012). An increased myocardial performance index is an early indicator of adverse perinatal outcomes in pregnancies complicated by idiopathic polyhydramnios. © 2016 by the American Institute of Ultrasound in Medicine.

  8. Lipid-Based Formulations Can Enable the Model Poorly Water-Soluble Weakly Basic Drug Cinnarizine to Precipitate in an Amorphous-Salt Form during in Vitro Digestion

    DEFF Research Database (Denmark)

    Khan, Jamal; Rades, Thomas; Boyd, Ben J

    2016-01-01

    weakly basic drug and was dissolved in a medium-chain (MC) LBF, which was subject to in vitro lipolysis experiments at various pH levels above and below the reported pKa value of cinnarizine (7.47). The solid-state form of the precipitated drug was analyzed using X-ray diffraction (XRD), Fourier......The tendency for poorly water-soluble weakly basic drugs to precipitate in a noncrystalline form during the in vitro digestion of lipid-based formulations (LBFs) was linked to an ionic interaction between drug and fatty acid molecules produced upon lipid digestion. Cinnarizine was chosen as a model...... from the starting free base crystalline material to the hydrochloride salt, thus supporting the case that ionic interactions between weak bases and fatty acid molecules during digestion are responsible for producing amorphous-salts upon precipitation. The conclusion has wide implications...

  9. Exploiting the Poor

    DEFF Research Database (Denmark)

    Kamp Justesen, Mogens; Bjørnskov, Christian

    2014-01-01

    While extant research has focused on the causes and consequences of corruption at the macro-level, less effort has been devoted to understanding the micro-foundation of corruption. We argue that poor people are more likely to be victims of corrupt behavior by street-level bureaucrats as the poor ...

  10. Inference in `poor` languages

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, S.

    1996-10-01

    Languages with a solvable implication problem but without complete and consistent systems of inference rules (`poor` languages) are considered. The problem of existence of finite complete and consistent inference rule system for a ``poor`` language is stated independently of the language or rules syntax. Several properties of the problem arc proved. An application of results to the language of join dependencies is given.

  11. Baseline elevated leukocyte count in peripheral blood is associated with poor survival in patients with advanced non-small cell lung cancer: a prognostic model.

    Science.gov (United States)

    Tibaldi, C; Vasile, E; Bernardini, I; Orlandini, C; Andreuccetti, M; Falcone, A

    2008-10-01

    We aimed to investigate the prognostic significance of several baseline variables in stage IIIB-IV non-small cell lung cancer to create a model based on independent prognostic factors. A total of 320 patients were treated with last generation chemotherapy regimens. The majority of patients received treatment with cisplatin + gemcitabine or gemcitabine alone if older than 70 years or with an ECOG performance status (PS) = 2. Performance status of 2, squamous histology, number of metastatic sites >2, presence of bone, brain, liver and contralateral lung metastases and elevated leukocyte count in peripheral blood were all statistically significant prognostic factors in univariate analyses whereas the other tested variables (sex, stage, age, presence of adrenal gland and skin metastases) were not. Subsequently, a multivariate Cox's regression analysis identified PS 2 (P leukocyte count (P Leukocyte count resulted the stronger factor after performance status. If prospectly validated, the proposed prognostic model could be useful to stratify performance status 2 patients in specific future trials.

  12. A Systemic Cause Analysis Model for Human Performance Technicians

    Science.gov (United States)

    Sostrin, Jesse

    2011-01-01

    This article presents a systemic, research-based cause analysis model for use in the field of human performance technology (HPT). The model organizes the most prominent barriers to workplace learning and performance into a conceptual framework that explains and illuminates the architecture of these barriers that exist within the fabric of everyday…

  13. Multitasking TORT under UNICOS: Parallel performance models and measurements

    International Nuclear Information System (INIS)

    Barnett, A.; Azmy, Y.Y.

    1999-01-01

    The existing parallel algorithms in the TORT discrete ordinates code were updated to function in a UNICOS environment. A performance model for the parallel overhead was derived for the existing algorithms. The largest contributors to the parallel overhead were identified and a new algorithm was developed. A parallel overhead model was also derived for the new algorithm. The results of the comparison of parallel performance models were compared to applications of the code to two TORT standard test problems and a large production problem. The parallel performance models agree well with the measured parallel overhead

  14. Multitasking TORT Under UNICOS: Parallel Performance Models and Measurements

    International Nuclear Information System (INIS)

    Azmy, Y.Y.; Barnett, D.A.

    1999-01-01

    The existing parallel algorithms in the TORT discrete ordinates were updated to function in a UNI-COS environment. A performance model for the parallel overhead was derived for the existing algorithms. The largest contributors to the parallel overhead were identified and a new algorithm was developed. A parallel overhead model was also derived for the new algorithm. The results of the comparison of parallel performance models were compared to applications of the code to two TORT standard test problems and a large production problem. The parallel performance models agree well with the measured parallel overhead

  15. Cost and Performance Assumptions for Modeling Electricity Generation Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Tidball, R.; Bluestein, J.; Rodriguez, N.; Knoke, S.

    2010-11-01

    The goal of this project was to compare and contrast utility scale power plant characteristics used in data sets that support energy market models. Characteristics include both technology cost and technology performance projections to the year 2050. Cost parameters include installed capital costs and operation and maintenance (O&M) costs. Performance parameters include plant size, heat rate, capacity factor or availability factor, and plant lifetime. Conventional, renewable, and emerging electricity generating technologies were considered. Six data sets, each associated with a different model, were selected. Two of the data sets represent modeled results, not direct model inputs. These two data sets include cost and performance improvements that result from increased deployment as well as resulting capacity factors estimated from particular model runs; other data sets represent model input data. For the technologies contained in each data set, the levelized cost of energy (LCOE) was also evaluated, according to published cost, performance, and fuel assumptions.

  16. A Probabilistic Approach to Symbolic Performance Modeling of Parallel Systems

    NARCIS (Netherlands)

    Gautama, H.

    2004-01-01

    Performance modeling plays a significant role in predicting the effects of a particular design choice or in diagnosing the cause for some observed performance behavior. Especially for complex systems such as parallel computer, typically, an intended performance cannot be achieved without recourse to

  17. Asymptotic performance modelling of DCF protocol with prioritized channel access

    Science.gov (United States)

    Choi, Woo-Yong

    2017-11-01

    Recently, the modification of the DCF (Distributed Coordination Function) protocol by the prioritized channel access was proposed to resolve the problem that the DCF performance worsens exponentially as more nodes exist in IEEE 802.11 wireless LANs. In this paper, an asymptotic analytical performance model is presented to analyze the MAC performance of the DCF protocol with the prioritized channel access.

  18. Maintenance personnel performance simulation (MAPPS): a model for predicting maintenance performance reliability in nuclear power plants

    International Nuclear Information System (INIS)

    Knee, H.E.; Krois, P.A.; Haas, P.M.; Siegel, A.I.; Ryan, T.G.

    1983-01-01

    The NRC has developed a structured, quantitative, predictive methodology in the form of a computerized simulation model for assessing maintainer task performance. Objective of the overall program is to develop, validate, and disseminate a practical, useful, and acceptable methodology for the quantitative assessment of NPP maintenance personnel reliability. The program was organized into four phases: (1) scoping study, (2) model development, (3) model evaluation, and (4) model dissemination. The program is currently nearing completion of Phase 2 - Model Development

  19. Performance and reliability model checking and model construction

    NARCIS (Netherlands)

    Hermanns, H.; Gnesi, Stefania; Schieferdecker, Ina; Rennoch, Axel

    2000-01-01

    Continuous-time Markov chains (CTMCs) are widely used to describe stochastic phenomena in many diverse areas. They are used to estimate performance and reliability characteristics of various nature, for instance to quantify throughputs of manufacturing systems, to locate bottlenecks in communication

  20. Automatic Performance Model Generation for Java Enterprise Edition (EE) Applications

    OpenAIRE

    Brunnert, Andreas;Vögele, Christian;Krcmar, Helmut

    2015-01-01

    The effort required to create performance models for enterprise applications is often out of proportion compared to their benefits. This work aims to reduce this effort by introducing an approach to automatically generate component-based performance models for running Java EE applications. The approach is applicable for all Java EE server products as it relies on standardized component types and interfaces to gather the required data for modeling an application. The feasibility of the approac...

  1. ECOPATH: Model description and evaluation of model performance

    International Nuclear Information System (INIS)

    Bergstroem, U.; Nordlinder, S.

    1996-01-01

    The model is based upon compartment theory and it is run in combination with a statistical error propagation method (PRISM, Gardner et al. 1983). It is intended to be generic for application on other sites with simple changing of parameter values. It was constructed especially for this scenario. However, it is based upon an earlier designed model for calculating relations between released amount of radioactivity and doses to critical groups (used for Swedish regulations concerning annual reports of released radioactivity from routine operation of Swedish nuclear power plants (Bergstroem och Nordlinder, 1991)). The model handles exposure from deposition on terrestrial areas as well as deposition on lakes, starting with deposition values. 14 refs, 16 figs, 7 tabs

  2. Indonesian Private University Lecturer Performance Improvement Model to Improve a Sustainable Organization Performance

    Science.gov (United States)

    Suryaman

    2018-01-01

    Lecturer performance will affect the quality and carrying capacity of the sustainability of an organization, in this case the university. There are many models developed to measure the performance of teachers, but not much to discuss the influence of faculty performance itself towards sustainability of an organization. This study was conducted in…

  3. Mathematical modelling of the transport of a poorly sorted granular mixture as a debris-flow. The case of Madeira Island torrential floods in 2010

    Science.gov (United States)

    Ferreira, Rui M. L.; Oliveira, Rodrigo P.; Conde, Daniel

    2016-04-01

    On the 20th February 2010, heavy rainfall was registered at Madeira Island, North Atlantic. Stony debris flows, mudflows and mudslides ensued causing severe property loss, 1.5 m thick sediment deposits at downtown Funchal including 16th century monuments, and a death toll of 47 lives. Debris-flow fronts propagated downstream while carrying very high concentrations of solid material. These two-phase solid-fluid flows were responsible for most of the infrastructural damage across the island, due to their significantly increased mass and momentum. The objective of the present modelling work is to validate a 2DH model for torrential flows featuring the transport and interaction of several size fractions of a poorly-sorted granular mixture typical of stony debris flow in Madeira. The module for the transport of poorly-sorted material was included in STAV-2D (CERIS-IST), a shallow-water and morphology solver based on a finite-volume method using a flux-splitting technique featuring a reviewed Roe-Riemann solver, with appropriate source-term formulations to ensure full conservativeness. STAV-2D also includes formulations of flow resistance and bedload transport adequate for debris-flows with natural mobile beds (Ferreira et al., 2009) and has been validated with both theoretical solutions and laboratory data (Soares-Frazão et al., 2012; Canelas et al., 2013). The modelling of the existing natural and built environment is fully explicit. All buildings, streets and channels are accurately represented within the mesh geometry. Such detail is relevant for the reliability of the validation using field data, since the major sedimentary deposits within the urban meshwork of Funchal were identified and characterized in terms of volume and grain size distribution during the aftermath of the 20th February of 2010 event. Indeed, the measure of the quality of the numerical results is the agreement between simulated and estimated volume of deposited sediment and between estimated and

  4. Comparison of two cash transfer strategies to prevent catastrophic costs for poor tuberculosis-affected households in low- and middle-income countries: An economic modelling study.

    Science.gov (United States)

    Rudgard, William E; Evans, Carlton A; Sweeney, Sedona; Wingfield, Tom; Lönnroth, Knut; Barreira, Draurio; Boccia, Delia

    2017-11-01

    Illness-related costs for patients with tuberculosis (TB) ≥20% of pre-illness annual household income predict adverse treatment outcomes and have been termed "catastrophic." Social protection initiatives, including cash transfers, are endorsed to help prevent catastrophic costs. With this aim, cash transfers may either be provided to defray TB-related costs of households with a confirmed TB diagnosis (termed a "TB-specific" approach); or to increase income of households with high TB risk to strengthen their economic resilience (termed a "TB-sensitive" approach). The impact of cash transfers provided with each of these approaches might vary. We undertook an economic modelling study from the patient perspective to compare the potential of these 2 cash transfer approaches to prevent catastrophic costs. Model inputs for 7 low- and middle-income countries (Brazil, Colombia, Ecuador, Ghana, Mexico, Tanzania, and Yemen) were retrieved by literature review and included countries' mean patient TB-related costs, mean household income, mean cash transfers, and estimated TB-specific and TB-sensitive target populations. Analyses were completed for drug-susceptible (DS) TB-related costs in all 7 out of 7 countries, and additionally for drug-resistant (DR) TB-related costs in 1 of the 7 countries with available data. All cost data were reported in 2013 international dollars ($). The target population for TB-specific cash transfers was poor households with a confirmed TB diagnosis, and for TB-sensitive cash transfers was poor households already targeted by countries' established poverty-reduction cash transfer programme. Cash transfers offered in countries, unrelated to TB, ranged from $217 to $1,091/year/household. Before cash transfers, DS TB-related costs were catastrophic in 6 out of 7 countries. If cash transfers were provided with a TB-specific approach, alone they would be insufficient to prevent DS TB catastrophic costs in 4 out of 6 countries, and when increased enough

  5. A Spectral Evaluation of Models Performances in Mediterranean Oak Woodlands

    Science.gov (United States)

    Vargas, R.; Baldocchi, D. D.; Abramowitz, G.; Carrara, A.; Correia, A.; Kobayashi, H.; Papale, D.; Pearson, D.; Pereira, J.; Piao, S.; Rambal, S.; Sonnentag, O.

    2009-12-01

    Ecosystem processes are influenced by climatic trends at multiple temporal scales including diel patterns and other mid-term climatic modes, such as interannual and seasonal variability. Because interactions between biophysical components of ecosystem processes are complex, it is important to test how models perform in frequency (e.g. hours, days, weeks, months, years) and time (i.e. day of the year) domains in addition to traditional tests of annual or monthly sums. Here we present a spectral evaluation using wavelet time series analysis of model performance in seven Mediterranean Oak Woodlands that encompass three deciduous and four evergreen sites. We tested the performance of five models (CABLE, ORCHIDEE, BEPS, Biome-BGC, and JULES) on measured variables of gross primary production (GPP) and evapotranspiration (ET). In general, model performance fails at intermediate periods (e.g. weeks to months) likely because these models do not represent the water pulse dynamics that influence GPP and ET at these Mediterranean systems. To improve the performance of a model it is critical to identify first where and when the model fails. Only by identifying where a model fails we can improve the model performance and use them as prognostic tools and to generate further hypotheses that can be tested by new experiments and measurements.

  6. Stunting, poor iron status and parasite infection are significant risk factors for lower cognitive performance in Cambodian school-aged children

    DEFF Research Database (Denmark)

    Perignon, Marlene; Fiorentino, Marion; Khov, Kuong

    2014-01-01

    BACKGROUND: Nutrition is one of many factors affecting the cognitive development of children. In Cambodia, 55% of children aged children, or on how malnutrition potentially affects...... their cognitive development. OBJECTIVE: To assess the anthropometric and micronutrient status (iron, vitamin A, zinc, iodine) of Cambodian schoolchildren and their associations with cognitive performance. METHODS: School children aged 6-16 y (n = 2443) from 20 primary schools in Cambodia were recruited....... Anthropometry, hemoglobin, serum ferritin, transferrin receptors, retinol-binding protein and zinc concentrations, inflammation status, urinary iodine concentration and parasite infection were measured. Socio-economic data were collected in a sub-group of children (n = 616). Cognitive performance was assessed...

  7. Atomic scale simulations for improved CRUD and fuel performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cooper, Michael William Donald [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-06

    A more mechanistic description of fuel performance codes can be achieved by deriving models and parameters from atomistic scale simulations rather than fitting models empirically to experimental data. The same argument applies to modeling deposition of corrosion products on fuel rods (CRUD). Here are some results from publications in 2016 carried out using the CASL allocation at LANL.

  8. modeling the effect of bandwidth allocation on network performance

    African Journals Online (AJOL)

    Modeling The Effect Of Bandwidth Allocation On Network Performance. MODELING THE EFFECT OF BANDWIDTH ... ABSTRACT. In this paper, a new channel capacity model for interference- limited systems was obtained .... congestion admission control, with the intent of minimizing energy consumption at each terminal.

  9. Modelling of Box Type Solar Cooker Performance in a Tropical ...

    African Journals Online (AJOL)

    Thermal performance model of box type solar cooker with loaded water is presented. The model was developed using the method of Funk to estimate cooking power in terms of climatic and design parameters for box type solar cooker in a tropical environment. Coefficients for each term used in the model were determined ...

  10. Comparisons of Faulting-Based Pavement Performance Prediction Models

    Directory of Open Access Journals (Sweden)

    Weina Wang

    2017-01-01

    Full Text Available Faulting prediction is the core of concrete pavement maintenance and design. Highway agencies are always faced with the problem of lower accuracy for the prediction which causes costly maintenance. Although many researchers have developed some performance prediction models, the accuracy of prediction has remained a challenge. This paper reviews performance prediction models and JPCP faulting models that have been used in past research. Then three models including multivariate nonlinear regression (MNLR model, artificial neural network (ANN model, and Markov Chain (MC model are tested and compared using a set of actual pavement survey data taken on interstate highway with varying design features, traffic, and climate data. It is found that MNLR model needs further recalibration, while the ANN model needs more data for training the network. MC model seems a good tool for pavement performance prediction when the data is limited, but it is based on visual inspections and not explicitly related to quantitative physical parameters. This paper then suggests that the further direction for developing the performance prediction model is incorporating the advantages and disadvantages of different models to obtain better accuracy.

  11. FARMLAND: Model description and evaluation of model performance

    International Nuclear Information System (INIS)

    Attwood, C.; Fayers, C.; Mayall, A.; Brown, J.; Simmonds, J.R.

    1996-01-01

    The FARMLAND model was originally developed for use in connection with continuous, routine releases of radionuclides, but because it has many time-dependent features it has been developed further for a single accidental release. The most recent version of FARMLAND is flexible and can be used to predict activity concentrations in food as a function of time after both accidental and routine releases of radionuclides. The effect of deposition at different times of the year can be taken into account. FARMLAND contains a suite of models which simulate radionuclide transfer through different parts of the foodchain. The models can be used in different combinations and offer the flexibility to assess a variety of radiological situations. The main foods considered are green vegetables, grain products, root vegetables, milk, meat and offal from cattle, and meat and offal from sheep. A large variety of elements can be considered although the degree of complexity with which some are modelled is greater than others; isotopes of caesium, strontium and iodine are treated in greatest detail. 22 refs, 12 figs, 10 tabs

  12. Performance of intra-procedural 18-fluorodeoxyglucose PET/CT-guided biopsies for lesions suspected of malignancy but poorly visualized with other modalities

    International Nuclear Information System (INIS)

    Cornelis, F.; Silk, M.; Takaki, H.; Durack, J.C.; Erinjeri, J.P.; Sofocleous, C.T.; Siegelbaum, R.H.; Maybody, M.; Solomon, S.B.; Schoder, H.

    2014-01-01

    We sought to evaluate the safety and the diagnostic success rate of percutaneous biopsies performed under intra-procedural 18 F-deoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT) guidance for lesions difficult to see with conventional cross-sectional imaging. From 2011 to 2013, consecutive clinically indicated percutaneous PET/CT-guided biopsies of 106 masses (mean size, 3.3 cm; range, 0.7-15.9 cm; SD, 2.9 cm) in bones (n = 33), liver (n = 26), soft tissues (n = 18), lung (n = 15) and abdomen (n = 14) were reviewed. The biopsy procedures were performed following injection of a mean of 255 MBq (SD, 74) FDG. Mean maximal standardized uptake value (SUV) of lesions was 8.8 (SD, 6.3). A systematic review of the histopathological results and outcomes was performed. Biopsies were positive for malignancy in 76 cases (71.7 %, 76/106) and for benign tissue in 30 cases (28.3 %, 30/106). Immediate results were considered adequate for 100 PET/CT biopsies (94.3 %, 100/106) requiring no further exploration, and for the six others (5.7 %, 6/106) benign diagnoses were confirmed after surgery (n = 4) or follow-up (n = 2). The consequent overall sensitivity and the diagnostic success of biopsy were therefore 100 %. No significant differences in terms of detection of malignancy were observed between the different locations. Lesions > 2 cm or with SUV > 4 were not significantly more likely to be malignant. Complications occurred after four biopsies (3.7 %, 4/106). Intra-procedural PET/CT guidance appears as a safe and effective method and allows high diagnostic success of percutaneous biopsies for metabolically active lesions. (orig.)

  13. Conceptual adsorption models and open issues pertaining to performance assessment

    International Nuclear Information System (INIS)

    Serne, R.J.

    1992-01-01

    Recently several articles have been published that question the appropriateness of the distribution coefficient, Rd, concept to quantify radionuclide migration. Several distinct issues surrounding the modeling of nuclide retardation. The first section defines adsorption terminology and discusses various adsorption processes. The next section describes five commonly used adsorption conceptual models, specifically emphasizing what attributes that affect adsorption are explicitly accommodated in each model. I also review efforts to incorporate each adsorption model into performance assessment transport computer codes. The five adsorption conceptual models are (1) the constant Rd model, (2) the parametric Rd model, (3) isotherm adsorption models, (4) mass action adsorption models, and (5) surface-complexation with electrostatics models. The final section discusses the adequacy of the distribution ratio concept, the adequacy of transport calculations that rely on constant retardation factors and the status of incorporating sophisticated adsorption models into transport codes. 86 refs., 1 fig., 1 tab

  14. Emerging Carbon Nanotube Electronic Circuits, Modeling, and Performance

    OpenAIRE

    Xu, Yao; Srivastava, Ashok; Sharma, Ashwani K.

    2010-01-01

    Current transport and dynamic models of carbon nanotube field-effect transistors are presented. A model of single-walled carbon nanotube as interconnect is also presented and extended in modeling of single-walled carbon nanotube bundles. These models are applied in studying the performances of circuits such as the complementary carbon nanotube inverter pair and carbon nanotube as interconnect. Cadence/Spectre simulations show that carbon nanotube field-effect transistor circuits can operate a...

  15. CORPORATE FORESIGHT AND PERFORMANCE: A CHAIN-OF-EFFECTS MODEL

    DEFF Research Database (Denmark)

    Jissink, Tymen; Huizingh, Eelko K.R.E.; Rohrbeck, René

    2015-01-01

    , formal organization, and culture. We investigate the relation of corporate foresight with three innovation performance dimensions – new product success, new product innovativeness, and financial performance. We use partial-least-squares structural equations modelling to assess our measurement mode ls......In this paper we develop and validate a measurement scale for corporate foresight and examine its impact on performance in a chain-of-effects model. We conceptualize corporate foresight as an organizational ability consisting of five distinct dimensions: information scope, method usage, people...... performance dimensions. Implications of our findings, and limitations and future research avenues are discussed....

  16. Low blood long chain omega-3 fatty acids in UK children are associated with poor cognitive performance and behavior: a cross-sectional analysis from the DOLAB study.

    Directory of Open Access Journals (Sweden)

    Paul Montgomery

    Full Text Available Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA, especially DHA (docosahexaenonic acid are essential for brain development and physical health. Low blood Omega-3 LC-PUFA have been reported in children with ADHD and related behavior/learning difficulties, as have benefits from dietary supplementation. Little is known, however, about blood fatty acid status in the general child population. We therefore investigated this in relation to age-standardized measures of behavior and cognition in a representative sample of children from mainstream schools.493 schoolchildren aged 7-9 years from mainstream Oxfordshire schools, selected for below average reading performance in national assessments at age seven.Whole blood fatty acids were obtained via fingerstick samples. Reading and working memory were assessed using the British Ability Scales (II. Behaviour (ADHD-type symptoms was rated using the revised Conners' rating scales (long parent and teacher versions. Associations were examined and adjusted for relevant demographic variables.DHA and eicosapentaenoic acid (EPA, accounted for only 1.9% and 0.55% respectively of total blood fatty acids, with DHA showing more individual variation. Controlling for sex and socio-economic status, lower DHA concentrations were associated with poorer reading ability (std. OLS coeff. = 0.09, p = <.042 and working memory performance (0.14, p = <.001. Lower DHA was also associated with higher levels of parent rated oppositional behavior and emotional lability (-0.175, p = <.0001 and -0.178, p = <.0001.In these healthy UK children with below average reading ability, concentrations of DHA and other Omega-3 LC-PUFA were low relative to adult cardiovascular health recommendations, and directly related to measures of cognition and behavior. These findings require confirmation, but suggest that the benefits from dietary supplementation with Omega-3 LC-PUFA found for ADHD, Dyspraxia, Dyslexia, and

  17. Desnutrição e baixo rendimento escolar: contribuições críticas Malnutrition and poor academic performance: critical contributions

    Directory of Open Access Journals (Sweden)

    Sandra Maria Sawaya

    2006-12-01

    Full Text Available O ARTIGO traz algumas contribuições da psicologia às reflexões sobre desnutrição e baixo rendimento escolar, a partir da análise de certas afirmações acerca das causas e conseqüências da desnutrição para o desenvolvimento infantil e a escolarização das crianças de classes populares. Analisa as suposições de que o baixo rendimento escolar de grande parcela dos alunos no Brasil teria como uma das suas explicações principais a desnutrição atual ou pregressa, o que supostamente levaria a deficiências cognitivas e lingüísticas, prejudicando a aprendizagem. O artigo discute ainda as metodologias de investigação e as análises que resultaram nessas conclusões. Finalmente, traz resultados de pesquisa que mostram a necessidade de revisão desses pressupostos, os quais continuam a orientar políticas e práticas educacionais e de saúde, o que inviabiliza a solução dos problemas escolares.THIS ARTICLE rises some contributions from psychology to the reflections on malnutrition and low school performance, through an analysis of some statements on the causes and consequences of malnutrition to child development as well as schooling of lower classes children. It analyses the assumptions that low performance at school of a great number of students in Brazil would be explained by the presence of malnutrition, current or previous. It critically discusses the investigative methodologies and analysis which presented questionable conclusions that children who are victims of malnutrition suffer from cognitive and linguistic deficiencies. Finally, it provides survey results, showing the need of reviewing these assumptions, since they continue to guide policies and practices on education and health, rendering impossible the solutions to school problems.

  18. Performance measurement of administration services using balance scorecard and Kano model

    Directory of Open Access Journals (Sweden)

    Abolfazl Danaei

    2014-04-01

    Full Text Available This paper performs a survey to measure the performance of an administration unit in Iran based on a popular technique of balance scorecard. The study also uses Kano model to prioritize various factors and to provide necessary recommendation to improve the performance of different units. The survey has indicated that while these offices do well in terms of financial figures as well as customer perspective, they perform poorly in terms of learning and growth. According to our survey, it is essential to use information technology in general service offices, properly. In addition, these administrative agencies need to use hardware and software packages, more efficiently and these two basic items have received much attraction.

  19. Models used to assess the performance of photovoltaic systems.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Klise, Geoffrey T.

    2009-12-01

    This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization. Energy storage plays an important role in reducing PV intermittency and battery storage models are used to understand the best configurations and technologies to store PV generated electricity. Other researcher's models used by SNL are discussed including some widely known models that incorporate algorithms developed at SNL. There are other models included in the discussion that are not used by or were not adopted from SNL research but may provide some benefit to researchers working on PV array performance, hybrid system models and energy storage. The paper is organized into three sections to describe the different software models as applied to photovoltaic performance, hybrid systems, and battery storage. For each model, there is a description which includes where to find the model, whether it is currently maintained and any references that may be available. Modeling improvements underway at SNL include quantifying the uncertainty of individual system components, the overall uncertainty in modeled vs. measured results and modeling large PV systems. SNL is also conducting research into the overall reliability of PV systems.

  20. A performance comparison of atmospheric dispersion models over complex topography

    International Nuclear Information System (INIS)

    Kido, Hiroko; Oishi, Ryoko; Hayashi, Keisuke; Kanno, Mitsuhiro; Kurosawa, Naohiro

    2007-01-01

    A code system using mass-consistent and Gaussian puff model was improved for a new option of atmospheric dispersion research. There are several atmospheric dispersion models for radionuclides. Because different models have both merits and disadvantages, it is necessary to choose the model that is most suitable for the surface conditions of the estimated region while regarding the calculation time, accuracy, and purpose of the calculations being performed. Some models are less accurate when the topography is complex. It is important to understand the differences between the models for smooth and complex surfaces. In this study, the performances of the following four models were compared: (1) Gaussian plume model (2) Gaussian puff model (3) Mass-consistent wind fields and Gaussian puff model that was improved in this study from one presented in Aomori Energy Society of Japan, 2005 Fall Meeting, D21. (4) Meso-scale meteorological model (RAMS: The Regional Atmospheric Modeling System) and particle-type model (HYPACT: The RAMS Hybrid Particle and Concentration Transport Model) (Reference: ATMET). (author)

  1. Confirming the Value of Swimming-Performance Models for Adolescents.

    Science.gov (United States)

    Dormehl, Shilo J; Robertson, Samuel J; Barker, Alan R; Williams, Craig A

    2017-10-01

    To evaluate the efficacy of existing performance models to assess the progression of male and female adolescent swimmers through a quantitative and qualitative mixed-methods approach. Fourteen published models were tested using retrospective data from an independent sample of Dutch junior national-level swimmers from when they were 12-18 y of age (n = 13). The degree of association by Pearson correlations was compared between the calculated differences from the models and quadratic functions derived from the Dutch junior national qualifying times. Swimmers were grouped based on their differences from the models and compared with their swimming histories that were extracted from questionnaires and follow-up interviews. Correlations of the deviations from both the models and quadratic functions derived from the Dutch qualifying times were all significant except for the 100-m breaststroke and butterfly and the 200-m freestyle for females (P backstroke for males and 200-m freestyle for males and females were almost directly proportional. In general, deviations from the models were accounted for by the swimmers' training histories. Higher levels of retrospective motivation appeared to be synonymous with higher-level career performance. This mixed-methods approach helped confirm the validity of the models that were found to be applicable to adolescent swimmers at all levels, allowing coaches to track performance and set goals. The value of the models in being able to account for the expected performance gains during adolescence enables quantification of peripheral factors that could affect performance.

  2. Adolescents with obstructive sleep apnea adhere poorly to positive airway pressure (PAP, but PAP users show improved attention and school performance.

    Directory of Open Access Journals (Sweden)

    Dean W Beebe

    2011-03-01

    Full Text Available Obstructive Sleep Apnea (OSA is associated with medical and neurobehavioral morbidity across the lifespan. Positive airway pressure (PAP treatment has demonstrated efficacy in treating OSA and has been shown to improve daytime functioning in adults, but treatment adherence can be problematic. There are nearly no published studies examining functional outcomes such as academic functioning in adolescents treated with PAP. This study was conducted as an initial step towards determining whether PAP treatment improves daytime functioning among adolescents with OSA.Self-reported academic grades, self- and parent-reported academic quality of life, and objectively-measured attention were assessed before and after PAP was clinically initiated in a sample of 13 obese adolescents with OSA, as well as 15 untreated obese Controls without OSA. Based on adherence data, the treated group was divided into PAP Users (n = 6 and Non-Adherent participants (n = 7.Though demographically similar, the three groups significantly differed in how their academic performance and attention scores changed from baseline to follow-up. Non-Adherent participants showed worsening functioning over time, while PAP Users showed stable or improved functioning, similar to controls.Although many adolescents prescribed PAP for OSA are non-adherent to the treatment, those who adhere to treatment can display improved attention and academic functioning.

  3. Adolescents with obstructive sleep apnea adhere poorly to positive airway pressure (PAP), but PAP users show improved attention and school performance.

    Science.gov (United States)

    Beebe, Dean W; Byars, Kelly C

    2011-03-17

    Obstructive Sleep Apnea (OSA) is associated with medical and neurobehavioral morbidity across the lifespan. Positive airway pressure (PAP) treatment has demonstrated efficacy in treating OSA and has been shown to improve daytime functioning in adults, but treatment adherence can be problematic. There are nearly no published studies examining functional outcomes such as academic functioning in adolescents treated with PAP. This study was conducted as an initial step towards determining whether PAP treatment improves daytime functioning among adolescents with OSA. Self-reported academic grades, self- and parent-reported academic quality of life, and objectively-measured attention were assessed before and after PAP was clinically initiated in a sample of 13 obese adolescents with OSA, as well as 15 untreated obese Controls without OSA. Based on adherence data, the treated group was divided into PAP Users (n = 6) and Non-Adherent participants (n = 7). Though demographically similar, the three groups significantly differed in how their academic performance and attention scores changed from baseline to follow-up. Non-Adherent participants showed worsening functioning over time, while PAP Users showed stable or improved functioning, similar to controls. Although many adolescents prescribed PAP for OSA are non-adherent to the treatment, those who adhere to treatment can display improved attention and academic functioning.

  4. A performance model of the OSI communication architecture

    Science.gov (United States)

    Kritzinger, P. S.

    1986-06-01

    An analytical model aiming at predicting the performance of software implementations which would be built according to the OSI basic reference model is proposed. The model uses the peer protocol standard of a layer as the reference description of an implementation of that layer. The model is basically a closed multiclass multichain queueing network with a processor-sharing center, modeling process contention at the processor, and a delay center, modeling times spent waiting for responses from the corresponding peer processes. Each individual transition of the protocol constitutes a different class and each layer of the architecture forms a closed chain. Performance statistics include queue lengths and response times at the processor as a function of processor speed and the number of open connections. It is shown how to reduce the model should the protocol state space become very large. Numerical results based upon the derived formulas are given.

  5. Performance evaluation:= (process algebra + model checking) x Markov chains

    NARCIS (Netherlands)

    Hermanns, H.; Larsen, K.G.; Nielsen, Mogens; Katoen, Joost P.

    2001-01-01

    Markov chains are widely used in practice to determine system performance and reliability characteristics. The vast majority of applications considers continuous-time Markov chains (CTMCs). This tutorial paper shows how successful model specification and analysis techniques from concurrency theory

  6. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    Science.gov (United States)

    Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

    2014-01-01

    This presentation describes the capabilities of three-dimensional thermal power model of advanced stirling radioisotope generator (ASRG). The performance of the ASRG is presented for different scenario, such as Venus flyby with or without the auxiliary cooling system.

  7. Practical Techniques for Modeling Gas Turbine Engine Performance

    Science.gov (United States)

    Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Jonathan S.

    2016-01-01

    The cost and risk associated with the design and operation of gas turbine engine systems has led to an increasing dependence on mathematical models. In this paper, the fundamentals of engine simulation will be reviewed, an example performance analysis will be performed, and relationships useful for engine control system development will be highlighted. The focus will be on thermodynamic modeling utilizing techniques common in industry, such as: the Brayton cycle, component performance maps, map scaling, and design point criteria generation. In general, these topics will be viewed from the standpoint of an example turbojet engine model; however, demonstrated concepts may be adapted to other gas turbine systems, such as gas generators, marine engines, or high bypass aircraft engines. The purpose of this paper is to provide an example of gas turbine model generation and system performance analysis for educational uses, such as curriculum creation or student reference.

  8. Testing algorithms for a passenger train braking performance model.

    Science.gov (United States)

    2011-09-01

    "The Federal Railroad Administrations Office of Research and Development funded a project to establish performance model to develop, analyze, and test positive train control (PTC) braking algorithms for passenger train operations. With a good brak...

  9. Dynamic vehicle model for handling performance using experimental data

    Directory of Open Access Journals (Sweden)

    SangDo Na

    2015-11-01

    Full Text Available An analytical vehicle model is essential for the development of vehicle design and performance. Various vehicle models have different complexities, assumptions and limitations depending on the type of vehicle analysis. An accurate full vehicle model is essential in representing the behaviour of the vehicle in order to estimate vehicle dynamic system performance such as ride comfort and handling. An experimental vehicle model is developed in this article, which employs experimental kinematic and compliance data measured between the wheel and chassis. From these data, a vehicle model, which includes dynamic effects due to vehicle geometry changes, has been developed. The experimental vehicle model was validated using an instrumented experimental vehicle and data such as a step change steering input. This article shows a process to develop and validate an experimental vehicle model to enhance the accuracy of handling performance, which comes from precise suspension model measured by experimental data of a vehicle. The experimental force data obtained from a suspension parameter measuring device are employed for a precise modelling of the steering and handling response. The steering system is modelled by a lumped model, with stiffness coefficients defined and identified by comparing steering stiffness obtained by the measured data. The outputs, specifically the yaw rate and lateral acceleration of the vehicle, are verified by experimental results.

  10. Evaluation Model of Organizational Performance for Small and Medium Enterprises

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Passos

    2014-12-01

    Full Text Available In the 1980’s, many tools for evaluating organizational performance were created. However, most of them are useful only to large companies and do not foster results in small and medium-sized enterprises (SMEs. In light of this fact, this article aims at proposing an Organizational Performance Assessment model (OPA which is flexible and adaptable to the reality of SMEs, based on the theoretical framework of various models, and comparisons on the basis of three major authors’ criteria to evaluate OPA models. The research has descriptive and exploratory character, with qualitative nature. The MADE-O model, according to the criteria described in the bibliography, is the one that best fits the needs of SMEs, used as a baseline for the model proposed in this study with adaptations pertaining to the BSC model. The model called the Overall Performance Indicator – Environment (IDG-E has as its main differential, in addition to the base of the models mentioned above, the assessment of the external and internal environment weighted in modules of OPA. As the SME is characterized by having few processes and people, the small amount of performance indicators is another positive aspect. Submitted to the evaluation of the criteria subscribed by the authors, the model proved to be quite feasible for use in SMEs.

  11. Model of service-oriented catering supply chain performance evaluation

    OpenAIRE

    Gou, Juanqiong; Shen, Guguan; Chai, Rui

    2013-01-01

    Purpose: The aim of this paper is constructing a performance evaluation model for service-oriented catering supply chain. Design/methodology/approach: With the research on the current situation of catering industry, this paper summarized the characters of the catering supply chain, and then presents the service-oriented catering supply chain model based on the platform of logistics and information. At last, the fuzzy AHP method is used to evaluate the performance of service-oriented catering ...

  12. ASSESSING INDIVIDUAL PERFORMANCE ON INFORMATION TECHNOLOGY ADOPTION: A NEW MODEL

    OpenAIRE

    Diah Hari Suryaningrum

    2012-01-01

    This paper aims to propose a new model in assessing individual performance on information technology adoption. The new model to assess individual performance was derived from two different theories: decomposed theory of planned behavior and task-technology fit theory. Although many researchers have tried to expand these theories, some of their efforts might lack of theoretical assumptions. To overcome this problem and enhance the coherence of the integration, I used a theory from social scien...

  13. Performance of Air Pollution Models on Massively Parallel Computers

    DEFF Research Database (Denmark)

    Brown, John; Hansen, Per Christian; Wasniewski, Jerzy

    1996-01-01

    To compare the performance and use of three massively parallel SIMD computers, we implemented a large air pollution model on the computers. Using a realistic large-scale model, we gain detailed insight about the performance of the three computers when used to solve large-scale scientific problems...... that involve several types of numerical computations. The computers considered in our study are the Connection Machines CM-200 and CM-5, and the MasPar MP-2216...

  14. Low cord-serum 25-hydroxyvitamin D levels are associated with poor lung function performance and increased respiratory infection in infancy.

    Directory of Open Access Journals (Sweden)

    Shen-Hao Lai

    Full Text Available Perinatal vitamin D deficiency is associated with a higher risk of wheezing in childhood. However, the relationship between vitamin D levels and lung function in infancy has not been investigated. The aim of this study was to investigate the impact of perinatal vitamin D levels on respiratory function and disease outcome in infancy.Full-term infants without any chronic diseases or major anomalies were enrolled in the Prediction of Allergies in Taiwanese Children cohort study. Maternal and cord blood were collected for determining the 25(OHD level. Questionnaires were recorded at birth and 6 months of age. Infant lung function, including tidal breathing analysis, respiratory mechanics, and forced tidal expiration, was tested at 6 months of age.A total of 122 mother-infant pairs were enrolled in this study, and 71 infants underwent lung function testing at 6 months of age. 25(OHD levels in maternal and cord serum were highly correlated (r2 = 0.457, p < 0.0001. Infants with lower cord serum 25(OHD levels (< 13.7 ng/ml had higher resistance of respiratory system (p < 0.01 and a higher risk of a respiratory tract infection before the age of 6 months (p < 0.01.Although a high correlation was found between maternal and cord vitamin D levels, the effect on respiratory outcome was different. Our study is the first to show that low cord 25(OHD levels significantly relationship with poorer lung function performance and higher likelihood of a respiratory tract infection before 6 months of age.

  15. A Mathematical Model to Improve the Performance of Logistics Network

    Directory of Open Access Journals (Sweden)

    Muhammad Izman Herdiansyah

    2012-01-01

    Full Text Available The role of logistics nowadays is expanding from just providing transportation and warehousing to offering total integrated logistics. To remain competitive in the global market environment, business enterprises need to improve their logistics operations performance. The improvement will be achieved when we can provide a comprehensive analysis and optimize its network performances. In this paper, a mixed integer linier model for optimizing logistics network performance is developed. It provides a single-product multi-period multi-facilities model, as well as the multi-product concept. The problem is modeled in form of a network flow problem with the main objective to minimize total logistics cost. The problem can be solved using commercial linear programming package like CPLEX or LINDO. Even in small case, the solver in Excel may also be used to solve such model.Keywords: logistics network, integrated model, mathematical programming, network optimization

  16. Construction Of A Performance Assessment Model For Zakat Management Institutions

    Directory of Open Access Journals (Sweden)

    Sri Fadilah

    2016-12-01

    Full Text Available The objective of the research is to examine the performance evaluation using Balanced Scorecard model. The research is conducted due to a big gap existing between zakat (alms and religious tax in Islam with its potential earn of as much as 217 trillion rupiahs and the realization of the collected zakat fund that is only reached for three trillion. This indicates that the performance of zakat management organizations in collecting the zakat is still very low. On the other hand, the quantity and the quality of zakat management organizations have to be improved. This means the performance evaluation model as a tool to evaluate performance is needed. The model construct is making a performance evaluation model that can be implemented to zakat management organizations. The organizational performance with Balanced Scorecard evaluation model will be effective if it is supported by three aspects, namely:  PI, BO and TQM. This research uses explanatory method and data analysis tool of SEM/PLS. Data collecting technique are questionnaires, interviews and documentation. The result of this research shows that PI, BO and TQM simultaneously and partially gives a significant effect on organizational performance.

  17. Team performance modeling for HRA in dynamic situations

    International Nuclear Information System (INIS)

    Shu Yufei; Furuta, Kazuo; Kondo, Shunsuke

    2002-01-01

    This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human-machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model

  18. Port performance evaluation tool based on microsimulation model

    Directory of Open Access Journals (Sweden)

    Tsavalista Burhani Jzolanda

    2017-01-01

    Full Text Available As port performance is becoming correlative to national competitiveness, the issue of port performance evaluation has significantly raised. Port performances can simply be indicated by port service levels to the ship (e.g., throughput, waiting for berthing etc., as well as the utilization level of equipment and facilities within a certain period. The performances evaluation then can be used as a tool to develop related policies for improving the port’s performance to be more effective and efficient. However, the evaluation is frequently conducted based on deterministic approach, which hardly captures the nature variations of port parameters. Therefore, this paper presents a stochastic microsimulation model for investigating the impacts of port parameter variations to the port performances. The variations are derived from actual data in order to provide more realistic results. The model is further developed using MATLAB and Simulink based on the queuing theory.

  19. Poor performance of quick-SOFA (qSOFA) score in predicting severe sepsis and mortality - a prospective study of patients admitted with infection to the emergency department.

    Science.gov (United States)

    Askim, Åsa; Moser, Florentin; Gustad, Lise T; Stene, Helga; Gundersen, Maren; Åsvold, Bjørn Olav; Dale, Jostein; Bjørnsen, Lars Petter; Damås, Jan Kristian; Solligård, Erik

    2017-06-09

    We aimed to evaluate the clinical usefulness of qSOFA as a risk stratification tool for patients admitted with infection compared to traditional SIRS criteria or our triage system; the Rapid Emergency Triage and Treatment System (RETTS). The study was an observational cohort study performed at one Emergency Department (ED) in an urban university teaching hospital in Norway, with approximately 20,000 visits per year. All patients >16 years presenting with symptoms or clinical signs suggesting an infection (n = 1535) were prospectively included in the study from January 1 to December 31, 2012. At arrival in the ED, vital signs were recorded and all patients were triaged according to RETTS vital signs, presenting infection, and sepsis symptoms. These admission data were also used to calculate qSOFA and SIRS. Treatment outcome was later retrieved from the patients' electronic records (EPR) and mortality data from the Norwegian population registry. Of the 1535 admitted patients, 108 (7.0%) fulfilled the Sepsis2 criteria for severe sepsis. The qSOFA score ≥2 identified only 33 (sensitivity 0.32, specificity 0.98) of the patients with severe sepsis, whilst the RETTS-alert ≥ orange identified 92 patients (sensitivity 0.85, specificity 0.55). Twenty-six patients died within 7 days of admission; four (15.4%) of them had a qSOFA ≥2, and 16 (61.5%) had RETTS ≥ orange alert. Of the 68 patients that died within 30 days, only eight (11.9%) scored ≥2 on the qSOFA, and 45 (66.1%) had a RETTS ≥ orange alert. In order to achieve timely treatment for sepsis, a sensitive screening tool is more important than a specific one. Our study is the fourth study were qSOFA finds few of the sepsis cases in prehospital or at arrival to the ED. We add information on the RETTS triage system, the two highest acuity levels together had a high sensitivity (85%) for identifying sepsis at arrival to the ED - and thus, RETTS should not be replaced by qSOFA as a screening and

  20. Toward a Subjective Measurement Model for Firm Performance

    Directory of Open Access Journals (Sweden)

    Luiz Artur Ledur Brito

    2012-05-01

    Full Text Available Firm performance is a relevant construct in strategic management research and frequently used as a dependentvariable. Despite this relevance, there is hardly a consensus about its definition, dimensionality andmeasurement, what limits advances in research and understanding of the concept. This article proposes and testsa measurement model for firm performance, based on subjective indicators. The model is grounded instakeholder theory and a review of empirical articles. Confirmatory Factor Analyses, using data from 116Brazilian senior managers, were used to test its fit and psychometric properties. The final model had six firstorderdimensions: profitability, growth, customer satisfaction, employee satisfaction, social performance, andenvironmental performance. A second-order financial performance construct, influencing growth andprofitability, correlated with the first-order intercorrelated, non-financial dimensions. Results suggest dimensionscannot be used interchangeably, since they represent different aspects of firm performance, and corroborate theidea that stakeholders have different demands that need to be managed independently. Researchers andpractitioners may use the model to fully treat performance in empirical studies and to understand the impact ofstrategies on multiple performance facets.

  1. A Composite Model for Employees' Performance Appraisal and Improvement

    Science.gov (United States)

    Manoharan, T. R.; Muralidharan, C.; Deshmukh, S. G.

    2012-01-01

    Purpose: The purpose of this paper is to develop an innovative method of performance appraisal that will be useful for designing a structured training programme. Design/methodology/approach: Employees' performance appraisals are conducted using new approaches, namely data envelopment analysis and an integrated fuzzy model. Interpretive structural…

  2. A Model for Effective Performance in the Indonesian Navy.

    Science.gov (United States)

    1987-06-01

    NAVY LEADERSHIP AND MANAGEMENT COM PETENCY M ODEL .................................. 15 D. MCBER COMPETENT MANAGERS MODEL ................ IS E. SU M M... leadership and managerial skills which emphasize on effective performance of the officers in managing the human resources under their cormnand and...supervision. By effective performance we mean officers who not only know about management theories , but who possess the characteristics, knowledge, skill, and

  3. Discussion of various models related to cloud performance

    OpenAIRE

    Kande, Chaitanya Krishna

    2015-01-01

    This paper discusses the various models related to cloud computing. Knowing the metrics related to infrastructure is very critical to enhance the performance of cloud services. Various metrics related to clouds such as pageview response time, admission control and enforcing elasticity to cloud infrastructure are very crucial in analyzing the characteristics of the cloud to enhance the cloud performance.

  4. Performance Implications of Business Model Change: A Case Study

    Directory of Open Access Journals (Sweden)

    Jana Poláková

    2015-01-01

    Full Text Available The paper deals with changes in performance level introduced by the change of business model. The selected case is a small family business undergoing through substantial changes in reflection of structural changes of its markets. The authors used the concept of business model to describe value creation processes within the selected family business and by contrasting the differences between value creation processes before and after the change introduced they prove the role of business model as the performance differentiator. This is illustrated with the use of business model canvas constructed on the basis interviews, observations and document analysis. The two business model canvases allow for explanation of cause-and-effect relationships within the business leading to change in performance. The change in the performance is assessed by financial analysis of the business conducted over the period of 2006–2012 demonstrates changes in performance (comparing development of ROA, ROE and ROS having their lowest levels before the change of business model was introduced, growing after the introduction of the change, as well as the activity indicators with similar developments of the family business. The described case study contributes to the concept of business modeling with the arguments supporting its value as strategic tool facilitating decisions related to value creation within the business.

  5. Conceptual Modeling of Performance Indicators of Higher Education Institutions

    OpenAIRE

    Kahveci, Tuba Canvar; Taşkın, Harun; Toklu, Merve Cengiz

    2013-01-01

    Measuring and analyzing any type of organization are carried out by different actors in the organization. The performance indicators of performance management system increase according to products or services of the organization. Also these indicators should be defined for all levels of the organization. Finally, all of these characteristics make the performance evaluation process more complex for organizations. In order to manage this complexity, the process should be modeled at the beginnin...

  6. Gold-standard performance for 2D hydrodynamic modeling

    Science.gov (United States)

    Pasternack, G. B.; MacVicar, B. J.

    2013-12-01

    Two-dimensional, depth-averaged hydrodynamic (2D) models are emerging as an increasingly useful tool for environmental water resources engineering. One of the remaining technical hurdles to the wider adoption and acceptance of 2D modeling is the lack of standards for 2D model performance evaluation when the riverbed undulates, causing lateral flow divergence and convergence. The goal of this study was to establish a gold-standard that quantifies the upper limit of model performance for 2D models of undulating riverbeds when topography is perfectly known and surface roughness is well constrained. A review was conducted of published model performance metrics and the value ranges exhibited by models thus far for each one. Typically predicted velocity differs from observed by 20 to 30 % and the coefficient of determination between the two ranges from 0.5 to 0.8, though there tends to be a bias toward overpredicting low velocity and underpredicting high velocity. To establish a gold standard as to the best performance possible for a 2D model of an undulating bed, two straight, rectangular-walled flume experiments were done with no bed slope and only different bed undulations and water surface slopes. One flume tested model performance in the presence of a porous, homogenous gravel bed with a long flat section, then a linear slope down to a flat pool bottom, and then the same linear slope back up to the flat bed. The other flume had a PVC plastic solid bed with a long flat section followed by a sequence of five identical riffle-pool pairs in close proximity, so it tested model performance given frequent undulations. Detailed water surface elevation and velocity measurements were made for both flumes. Comparing predicted versus observed velocity magnitude for 3 discharges with the gravel-bed flume and 1 discharge for the PVC-bed flume, the coefficient of determination ranged from 0.952 to 0.987 and the slope for the regression line was 0.957 to 1.02. Unsigned velocity

  7. The Social Responsibility Performance Outcomes Model: Building Socially Responsible Companies through Performance Improvement Outcomes.

    Science.gov (United States)

    Hatcher, Tim

    2000-01-01

    Considers the role of performance improvement professionals and human resources development professionals in helping organizations realize the ethical and financial power of corporate social responsibility. Explains the social responsibility performance outcomes model, which incorporates the concepts of societal needs and outcomes. (LRW)

  8. Faculty Performance Evaluation: The CIPP-SAPS Model.

    Science.gov (United States)

    Mitcham, Maralynne

    1981-01-01

    The issues of faculty performance evaluation for allied health professionals are addressed. Daniel Stufflebeam's CIPP (content-imput-process-product) model is introduced and its development into a CIPP-SAPS (self-administrative-peer- student) model is pursued. (Author/CT)

  9. Technical performance of percutaneous and laminectomy leads analyzed by modeling

    NARCIS (Netherlands)

    Manola, L.; Holsheimer, J.

    2004-01-01

    The objective of this study was to compare the technical performance of laminectomy and percutaneous spinal cord stimulation leads with similar contact spacing by computer modeling. Monopolar and tripolar (guarded cathode) stimulation with both lead types in a low-thoracic spine model was simulated

  10. Neuro-fuzzy model for evaluating the performance of processes ...

    Indian Academy of Sciences (India)

    CHIDOZIE CHUKWUEMEKA NWOBI-OKOYE

    2017-11-16

    Nov 16, 2017 ... In this work an Adaptive Neuro-Fuzzy Inference System (ANFIS) was used to model the periodic performance of some ..... Every node i in this layer is an adaptive node with a node function. Neuro-fuzzy model for .... spectral analysis and parameter optimization using genetic algorithm, the values of v10. and ...

  11. UNCONSTRAINED HANDWRITING RECOGNITION : LANGUAGE MODELS, PERPLEXITY, AND SYSTEM PERFORMANCE

    NARCIS (Netherlands)

    Marti, U-V.; Bunke, H.

    2004-01-01

    In this paper we present a number of language models and their behavior in the recognition of unconstrained handwritten English sentences. We use the perplexity to compare the different models and their prediction power, and relate it to the performance of a recognition system under different

  12. Mathematical Models of Elementary Mathematics Learning and Performance. Final Report.

    Science.gov (United States)

    Suppes, Patrick

    This project was concerned with the development of mathematical models of elementary mathematics learning and performance. Probabilistic finite automata and register machines with a finite number of registers were developed as models and extensively tested with data arising from the elementary-mathematics strand curriculum developed by the…

  13. Activity-Based Costing Model for Assessing Economic Performance.

    Science.gov (United States)

    DeHayes, Daniel W.; Lovrinic, Joseph G.

    1994-01-01

    An economic model for evaluating the cost performance of academic and administrative programs in higher education is described. Examples from its application at Indiana University-Purdue University Indianapolis are used to illustrate how the model has been used to control costs and reengineer processes. (Author/MSE)

  14. Longitudinal modeling in sports: young swimmers' performance and biomechanics profile.

    Science.gov (United States)

    Morais, Jorge E; Marques, Mário C; Marinho, Daniel A; Silva, António J; Barbosa, Tiago M

    2014-10-01

    New theories about dynamical systems highlight the multi-factorial interplay between determinant factors to achieve higher sports performances, including in swimming. Longitudinal research does provide useful information on the sportsmen's changes and how training help him to excel. These questions may be addressed in one single procedure such as latent growth modeling. The aim of the study was to model a latent growth curve of young swimmers' performance and biomechanics over a season. Fourteen boys (12.33 ± 0.65 years-old) and 16 girls (11.15 ± 0.55 years-old) were evaluated. Performance, stroke frequency, speed fluctuation, arm's propelling efficiency, active drag, active drag coefficient and power to overcome drag were collected in four different moments of the season. Latent growth curve modeling was computed to understand the longitudinal variation of performance (endogenous variables) over the season according to the biomechanics (exogenous variables). Latent growth curve modeling showed a high inter- and intra-subject variability in the performance growth. Gender had a significant effect at the baseline and during the performance growth. In each evaluation moment, different variables had a meaningful effect on performance (M1: Da, β = -0.62; M2: Da, β = -0.53; M3: η(p), β = 0.59; M4: SF, β = -0.57; all P < .001). The models' goodness-of-fit was 1.40 ⩽ χ(2)/df ⩽ 3.74 (good-reasonable). Latent modeling is a comprehensive way to gather insight about young swimmers' performance over time. Different variables were the main responsible for the performance improvement. A gender gap, intra- and inter-subject variability was verified. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Comparison of the performance of net radiation calculation models

    DEFF Research Database (Denmark)

    Kjærsgaard, Jeppe Hvelplund; Cuenca, R.H.; Martinez-Cob, A.

    2009-01-01

    Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily....... The performance of the empirical models was nearly identical at all sites. Since the empirical models were easier to use and simpler to calibrate than the physically based models, the results indicate that the empirical models can be used as a good substitute for the physically based ones when available...

  16. Modeling the future of irrigation: A parametric description of pressure compensating drip irrigation emitter performance.

    Directory of Open Access Journals (Sweden)

    Pulkit Shamshery

    Full Text Available Drip irrigation is a means of distributing the exact amount of water a plant needs by dripping water directly onto the root zone. It can produce up to 90% more crops than rain-fed irrigation, and reduce water consumption by 70% compared to conventional flood irrigation. Drip irrigation may enable millions of poor farmers to rise out of poverty by growing more and higher value crops, while not contributing to overconsumption of water. Achieving this impact will require broadening the engineering knowledge required to design new, low-cost, low-power drip irrigation technology, particularly for poor, off-grid communities in developing countries. For more than 50 years, pressure compensating (PC drip emitters-which can maintain a constant flow rate under variations in pressure, to ensure uniform water distribution on a field-have been designed and optimized empirically. This study presents a parametric model that describes the fluid and solid mechanics that govern the behavior of a common PC emitter architecture, which uses a flexible diaphragm to limit flow. The model was validated by testing nine prototypes with geometric variations, all of which matched predicted performance to within R2 = 0.85. This parametric model will enable irrigation engineers to design new drip emitters with attributes that improve performance and lower cost, which will promote the use of drip irrigation throughout the world.

  17. Modeling the future of irrigation: A parametric description of pressure compensating drip irrigation emitter performance.

    Science.gov (United States)

    Shamshery, Pulkit; Wang, Ruo-Qian; Tran, Davis V; Winter V, Amos G

    2017-01-01

    Drip irrigation is a means of distributing the exact amount of water a plant needs by dripping water directly onto the root zone. It can produce up to 90% more crops than rain-fed irrigation, and reduce water consumption by 70% compared to conventional flood irrigation. Drip irrigation may enable millions of poor farmers to rise out of poverty by growing more and higher value crops, while not contributing to overconsumption of water. Achieving this impact will require broadening the engineering knowledge required to design new, low-cost, low-power drip irrigation technology, particularly for poor, off-grid communities in developing countries. For more than 50 years, pressure compensating (PC) drip emitters-which can maintain a constant flow rate under variations in pressure, to ensure uniform water distribution on a field-have been designed and optimized empirically. This study presents a parametric model that describes the fluid and solid mechanics that govern the behavior of a common PC emitter architecture, which uses a flexible diaphragm to limit flow. The model was validated by testing nine prototypes with geometric variations, all of which matched predicted performance to within R2 = 0.85. This parametric model will enable irrigation engineers to design new drip emitters with attributes that improve performance and lower cost, which will promote the use of drip irrigation throughout the world.

  18. An analytical model of the HINT performance metric

    Energy Technology Data Exchange (ETDEWEB)

    Snell, Q.O.; Gustafson, J.L. [Scalable Computing Lab., Ames, IA (United States)

    1996-10-01

    The HINT benchmark was developed to provide a broad-spectrum metric for computers and to measure performance over the full range of memory sizes and time scales. We have extended our understanding of why HINT performance curves look the way they do and can now predict the curves using an analytical model based on simple hardware specifications as input parameters. Conversely, by fitting the experimental curves with the analytical model, hardware specifications such as memory performance can be inferred to provide insight into the nature of a given computer system.

  19. Disaggregation of Rainy Hours: Compared Performance of Various Models.

    Science.gov (United States)

    Ben Haha, M.; Hingray, B.; Musy, A.

    In the urban environment, the response times of catchments are usually short. To de- sign or to diagnose waterworks in that context, it is necessary to describe rainfall events with a good time resolution: a 10mn time step is often necessary. Such in- formation is not always available. Rainfall disaggregation models have thus to be applied to produce from rough rainfall data that short time resolution information. The communication will present the performance obtained with several rainfall dis- aggregation models that allow for the disaggregation of rainy hours into six 10mn rainfall amounts. The ability of the models to reproduce some statistical character- istics of rainfall (mean, variance, overall distribution of 10mn-rainfall amounts; ex- treme values of maximal rainfall amounts over different durations) is evaluated thanks to different graphical and numerical criteria. The performance of simple models pre- sented in some scientific papers or developed in the Hydram laboratory as well as the performance of more sophisticated ones is compared with the performance of the basic constant disaggregation model. The compared models are either deterministic or stochastic; for some of them the disaggregation is based on scaling properties of rainfall. The compared models are in increasing complexity order: constant model, linear model (Ben Haha, 2001), Ormsbee Deterministic model (Ormsbee, 1989), Ar- tificial Neuronal Network based model (Burian et al. 2000), Hydram Stochastic 1 and Hydram Stochastic 2 (Ben Haha, 2001), Multiplicative Cascade based model (Olsson and Berndtsson, 1998), Ormsbee Stochastic model (Ormsbee, 1989). The 625 rainy hours used for that evaluation (with a hourly rainfall amount greater than 5mm) were extracted from the 21 years chronological rainfall series (10mn time step) observed at the Pully meteorological station, Switzerland. The models were also evaluated when applied to different rainfall classes depending on the season first and on the

  20. 9. Poor medication

    African Journals Online (AJOL)

    Sitwala

    Majority (60%) of the patients were reviewed at least twice in the last 6 months at the time of the interview. 195 (83%) patients reported that drugs prescribed were not available at the hospital pharmacy, but 186 (79%) of. Factors Associated With Poor Medication Adherence. In Hypertensive Patients In Lusaka, Zambia. 1,4. 1.

  1. A poor deal

    NARCIS (Netherlands)

    Breman, J.

    2010-01-01

    The proposed upward revision of the poverty line has failed to capture the Janus-faced deprivation experienced by the poor. The methodological foundation of the proposed poverty line fails to overcome the discrepancy between the macro-statistics and the micro-reality. The proposed report on the

  2. Becoming poor in Ghana

    African Journals Online (AJOL)

    income related, in order to bring their consumption below the poverty line for a short or long time. Keywords: .... Ten short cases of families that have become poor in an urban setting in Ghana will be pre- sented. ..... farm, together with higher prices on both inputs and necessary consumer goods, forced him to sell part of the ...

  3. Morphosyntax in Poor Comprehenders

    Science.gov (United States)

    Adlof, Suzanne M.; Catts, Hugh W.

    2015-01-01

    Children described as "poor comprehenders" (PCs) have reading comprehension difficulties in spite of adequate word reading abilities. PCs are known to display weakness with semantics and higher-level aspects of oral language, but less is known about their grammatical skills, especially with regard to morphosyntax. The purpose of this…

  4. A network application for modeling a centrifugal compressor performance map

    Science.gov (United States)

    Nikiforov, A.; Popova, D.; Soldatova, K.

    2017-08-01

    The approximation of aerodynamic performance of a centrifugal compressor stage and vaneless diffuser by neural networks is presented. Advantages, difficulties and specific features of the method are described. An example of a neural network and its structure is shown. The performances in terms of efficiency, pressure ratio and work coefficient of 39 model stages within the range of flow coefficient from 0.01 to 0.08 were modeled with mean squared error 1.5 %. In addition, the loss and friction coefficients of vaneless diffusers of relative widths 0.014-0.10 are modeled with mean squared error 2.45 %.

  5. Assessment of performance of survival prediction models for cancer prognosis

    Directory of Open Access Journals (Sweden)

    Chen Hung-Chia

    2012-07-01

    Full Text Available Abstract Background Cancer survival studies are commonly analyzed using survival-time prediction models for cancer prognosis. A number of different performance metrics are used to ascertain the concordance between the predicted risk score of each patient and the actual survival time, but these metrics can sometimes conflict. Alternatively, patients are sometimes divided into two classes according to a survival-time threshold, and binary classifiers are applied to predict each patient’s class. Although this approach has several drawbacks, it does provide natural performance metrics such as positive and negative predictive values to enable unambiguous assessments. Methods We compare the survival-time prediction and survival-time threshold approaches to analyzing cancer survival studies. We review and compare common performance metrics for the two approaches. We present new randomization tests and cross-validation methods to enable unambiguous statistical inferences for several performance metrics used with the survival-time prediction approach. We consider five survival prediction models consisting of one clinical model, two gene expression models, and two models from combinations of clinical and gene expression models. Results A public breast cancer dataset was used to compare several performance metrics using five prediction models. 1 For some prediction models, the hazard ratio from fitting a Cox proportional hazards model was significant, but the two-group comparison was insignificant, and vice versa. 2 The randomization test and cross-validation were generally consistent with the p-values obtained from the standard performance metrics. 3 Binary classifiers highly depended on how the risk groups were defined; a slight change of the survival threshold for assignment of classes led to very different prediction results. Conclusions 1 Different performance metrics for evaluation of a survival prediction model may give different conclusions in

  6. Hybrid Corporate Performance Prediction Model Considering Technical Capability

    Directory of Open Access Journals (Sweden)

    Joonhyuck Lee

    2016-07-01

    Full Text Available Many studies have tried to predict corporate performance and stock prices to enhance investment profitability using qualitative approaches such as the Delphi method. However, developments in data processing technology and machine-learning algorithms have resulted in efforts to develop quantitative prediction models in various managerial subject areas. We propose a quantitative corporate performance prediction model that applies the support vector regression (SVR algorithm to solve the problem of the overfitting of training data and can be applied to regression problems. The proposed model optimizes the SVR training parameters based on the training data, using the genetic algorithm to achieve sustainable predictability in changeable markets and managerial environments. Technology-intensive companies represent an increasing share of the total economy. The performance and stock prices of these companies are affected by their financial standing and their technological capabilities. Therefore, we apply both financial indicators and technical indicators to establish the proposed prediction model. Here, we use time series data, including financial, patent, and corporate performance information of 44 electronic and IT companies. Then, we predict the performance of these companies as an empirical verification of the prediction performance of the proposed model.

  7. Facial Performance Transfer via Deformable Models and Parametric Correspondence.

    Science.gov (United States)

    Asthana, Akshay; de la Hunty, Miles; Dhall, Abhinav; Goecke, Roland

    2012-09-01

    The issue of transferring facial performance from one person's face to another's has been an area of interest for the movie industry and the computer graphics community for quite some time. In recent years, deformable face models, such as the Active Appearance Model (AAM), have made it possible to track and synthesize faces in real time. Not surprisingly, deformable face model-based approaches for facial performance transfer have gained tremendous interest in the computer vision and graphics community. In this paper, we focus on the problem of real-time facial performance transfer using the AAM framework. We propose a novel approach of learning the mapping between the parameters of two completely independent AAMs, using them to facilitate the facial performance transfer in a more realistic manner than previous approaches. The main advantage of modeling this parametric correspondence is that it allows a "meaningful" transfer of both the nonrigid shape and texture across faces irrespective of the speakers' gender, shape, and size of the faces, and illumination conditions. We explore linear and nonlinear methods for modeling the parametric correspondence between the AAMs and show that the sparse linear regression method performs the best. Moreover, we show the utility of the proposed framework for a cross-language facial performance transfer that is an area of interest for the movie dubbing industry.

  8. Real-time individualization of the unified model of performance.

    Science.gov (United States)

    Liu, Jianbo; Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Balkin, Thomas J; Reifman, Jaques

    2017-12-01

    Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produced by a post-hoc fitting of model parameters using all data. The minimum number of PVT measurements needed to individualize the model parameters depended upon the type of sleep-loss challenge, with ~30 required for TSD and ~70 for CSR. However, model individualization depended upon the overall duration of data collection, yielding increasingly accurate model parameters with greater number of days. Interestingly, reducing the PVT sampling frequency by a factor of two did not notably hamper model individualization. The proposed algorithm facilitates real-time learning of an individual's trait-like responses to sleep loss and enables the development of individualized performance prediction models for use in a mobile computing platform. © 2017 European Sleep Research Society.

  9. Observer analysis and its impact on task performance modeling

    Science.gov (United States)

    Jacobs, Eddie L.; Brown, Jeremy B.

    2014-05-01

    Fire fighters use relatively low cost thermal imaging cameras to locate hot spots and fire hazards in buildings. This research describes the analyses performed to study the impact of thermal image quality on fire fighter fire hazard detection task performance. Using human perception data collected by the National Institute of Standards and Technology (NIST) for fire fighters detecting hazards in a thermal image, an observer analysis was performed to quantify the sensitivity and bias of each observer. Using this analysis, the subjects were divided into three groups representing three different levels of performance. The top-performing group was used for the remainder of the modeling. Models were developed which related image quality factors such as contrast, brightness, spatial resolution, and noise to task performance probabilities. The models were fitted to the human perception data using logistic regression, as well as probit regression. Probit regression was found to yield superior fits and showed that models with not only 2nd order parameter interactions, but also 3rd order parameter interactions performed the best.

  10. System Level Modelling and Performance Estimation of Embedded Systems

    DEFF Research Database (Denmark)

    Tranberg-Hansen, Anders Sejer

    The advances seen in the semiconductor industry within the last decade have brought the possibility of integrating evermore functionality onto a single chip forming functionally highly advanced embedded systems. These integration possibilities also imply that as the design complexity increases, so...... an efficient system level design methodology, a modelling framework for performance estimation and design space exploration at the system level is required. This thesis presents a novel component based modelling framework for system level modelling and performance estimation of embedded systems. The framework...... is performed by having the framework produce detailed quantitative information about the system model under investigation. The project is part of the national Danish research project, Danish Network of Embedded Systems (DaNES), which is funded by the Danish National Advanced Technology Foundation. The project...

  11. Causal Analysis for Performance Modeling of Computer Programs

    Directory of Open Access Journals (Sweden)

    Jan Lemeire

    2007-01-01

    Full Text Available Causal modeling and the accompanying learning algorithms provide useful extensions for in-depth statistical investigation and automation of performance modeling. We enlarged the scope of existing causal structure learning algorithms by using the form-free information-theoretic concept of mutual information and by introducing the complexity criterion for selecting direct relations among equivalent relations. The underlying probability distribution of experimental data is estimated by kernel density estimation. We then reported on the benefits of a dependency analysis and the decompositional capacities of causal models. Useful qualitative models, providing insight into the role of every performance factor, were inferred from experimental data. This paper reports on the results for a LU decomposition algorithm and on the study of the parameter sensitivity of the Kakadu implementation of the JPEG-2000 standard. Next, the analysis was used to search for generic performance characteristics of the applications.

  12. Impact of reactive settler models on simulated WWTP performance.

    Science.gov (United States)

    Gernaey, K V; Jeppsson, U; Batstone, D J; Ingildsen, P

    2006-01-01

    Including a reactive settler model in a wastewater treatment plant model allows representation of the biological reactions taking place in the sludge blanket in the settler, something that is neglected in many simulation studies. The idea of including a reactive settler model is investigated for an ASM1 case study. Simulations with a whole plant model including the non-reactive Takács settler model are used as a reference, and are compared to simulation results considering two reactive settler models. The first is a return sludge model block removing oxygen and a user-defined fraction of nitrate, combined with a non-reactive Takács settler. The second is a fully reactive ASM1 Takács settler model. Simulations with the ASM1 reactive settler model predicted a 15.3% and 7.4% improvement of the simulated N removal performance, for constant (steady-state) and dynamic influent conditions respectively. The oxygen/nitrate return sludge model block predicts a 10% improvement of N removal performance under dynamic conditions, and might be the better modelling option for ASM1 plants: it is computationally more efficient and it will not overrate the importance of decay processes in the settler.

  13. Some considerations for validation of repository performance assessment models

    International Nuclear Information System (INIS)

    Eisenberg, N.

    1991-01-01

    Validation is an important aspect of the regulatory uses of performance assessment. A substantial body of literature exists indicating the manner in which validation of models is usually pursued. Because performance models for a nuclear waste repository cannot be tested over the long time periods for which the model must make predictions, the usual avenue for model validation is precluded. Further impediments to model validation include a lack of fundamental scientific theory to describe important aspects of repository performance and an inability to easily deduce the complex, intricate structures characteristic of a natural system. A successful strategy for validation must attempt to resolve these difficulties in a direct fashion. Although some procedural aspects will be important, the main reliance of validation should be on scientific substance and logical rigor. The level of validation needed will be mandated, in part, by the uses to which these models are put, rather than by the ideal of validation of a scientific theory. Because of the importance of the validation of performance assessment models, the NRC staff has engaged in a program of research and international cooperation to seek progress in this important area. 2 figs., 16 refs

  14. Evaluating Flight Crew Performance by a Bayesian Network Model

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2018-03-01

    Full Text Available Flight crew performance is of great significance in keeping flights safe and sound. When evaluating the crew performance, quantitative detailed behavior information may not be available. The present paper introduces the Bayesian Network to perform flight crew performance evaluation, which permits the utilization of multidisciplinary sources of objective and subjective information, despite sparse behavioral data. In this paper, the causal factors are selected based on the analysis of 484 aviation accidents caused by human factors. Then, a network termed Flight Crew Performance Model is constructed. The Delphi technique helps to gather subjective data as a supplement to objective data from accident reports. The conditional probabilities are elicited by the leaky noisy MAX model. Two ways of inference for the BN—probability prediction and probabilistic diagnosis are used and some interesting conclusions are drawn, which could provide data support to make interventions for human error management in aviation safety.

  15. A modified MELD model for Chinese pre-ACLF and ACLF patients and it reveals poor prognosis in pre-ACLF patients.

    Directory of Open Access Journals (Sweden)

    Qi Xia

    Full Text Available BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF is one of the most deadly, prevalent, and costly diseases in Asia. However, no prognostic model has been developed that is based specifically on data gathered from Asian patients with ACLF. The aim of the present study was to quantify the survival time of ACLF among Asians and to develop a prognostic model to estimate the probability of death related to ACLF. METHODS: We conducted a retrospective observational cohort study to analyze clinical data from 857 patients with ACLF/pre-ACLF who did not undergo liver transplantation. Kaplan-Meier and Cox proportional hazards regression model were used to estimate survival rates and survival affected factors. The area under the receiver operating characteristic curve (auROC was used to evaluate the performance of the models for predicting early mortality. RESULTS: The mortality rates among patients with pre-ACLF at 12 weeks and 24 weeks after diagnosis were 30.5% and 33.2%, respectively. The mortality rates among patients with early-stage ACLF at 12 weeks and 24 weeks after diagnosis were 33.9% and 37.1%, respectively. The difference in survival between pre-ACLF patients and patients in the early stage of ACLF was not statistically significant. The prognostic model identified 5 independent factors significantly associated with survival among patients with ACLF and pre-ACLF: the model for end-stage liver disease (MELD score; age, hepatic encephalopathy; triglyceride level and platelet count. CONCLUSION: The findings of the present study suggest that the Chinese diagnostic criteria of ACLF might be broadened, thus enabling implementation of a novel model to predict ACLF-related death after comprehensive medical treatment.

  16. Predictors of Poor Pregnancy Outcomes Among Antenatal Care Attendees in Primary Health Care Facilities in Cross River State, Nigeria: A Multilevel Model

    OpenAIRE

    Ameh, Soter; Adeleye, Omokhoa A.; Kabiru, Caroline W.; Agan, Thomas; Duke, Roseline; Mkpanam, Nkese; Nwoha, Doris

    2016-01-01

    Objectives Pregnancy carries a high risk for millions of women and varies by urban?rural location in Nigeria, a country with the second highest maternal deaths in the world. Addressing multilevel predictors of poor pregnancy outcomes among antenatal care (ANC) attendees in primary health care (PHC) facilities could reduce the high maternal mortality rate in Nigeria. This study utilised the ?Risk Approach? strategy to (1) compare the risks of poor pregnancy outcomes among ANC attendees by urba...

  17. Application Of Hydrological Models In Poorly Gauged Watersheds A Review Of The Usage Of The Soil And Water Assessment Tool SWAT In Kenya

    OpenAIRE

    Wambugu Mwangi; Nyandega Isaiah; Kamp305thiia Shadrack

    2017-01-01

    In water-scarce developing countries river basins are some of the most valued natural resources but many are poorly gauged and have incomplete hydrological and climate records. In the recent years tropical rivers are increasingly becoming erratic with many hydrologists attributing this variability to combined effects of landscape-specific anthropogenic activities and climate change. Uncertainties about the impacts of climate change compound the challenges attributed to poor and often inconsis...

  18. LOCALITY UNCERTAINTY AND THE DIFFERENTIAL PERFORMANCE OF FOUR COMMON NICHE-BASED MODELING TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Miguel Fernandez

    2009-09-01

    Full Text Available We address a poorly understood aspect of ecological niche modeling: its sensitivity to different levels of geographic uncertainty in organism occurrence data. Our primary interest was to assess how accuracy degrades under increasing uncertainty, with performance measured indirectly through model consistency. We used Monte Carlo simulations and a similarity measure to assess model sensitivity across three variables: locality accuracy, niche modeling method, and species. Randomly generated data sets with known levels of locality uncertainty were compared to an original prediction using Fuzzy Kappa. Data sets where locality uncertainty is low were expected to produce similar distribution maps to the original. In contrast, data sets where locality uncertainty is high were expected to produce less similar maps. BIOCLIM, DOMAIN, Maxent and GARP were used to predict the distributions for 1200 simulated datasets (3 species x 4 buffer sizes x 100 randomized data sets. Thus, our experimental design produced a total of 4800 similarity measures, with each of the simulated distributions compared to the prediction of the original data set and corresponding modeling method. A general linear model (GLM analysis was performed which enables us to simultaneously measure the effect of buffer size, modeling method, and species, as well as interactions among all variables. Our results show that modeling method has the largest effect on similarity scores and uniquely accounts for 40% of the total variance in the model. The second most important factor was buffer size, but it uniquely accounts for only 3% of the variation in the model. The newer and currently more popular methods, GARP and Maxent, were shown to produce more inconsistent predictions than the earlier and simpler methods, BIOCLIM and DOMAIN. Understanding the performance of different niche modeling methods under varying levels of geographic uncertainty is an important step toward more productive

  19. What characterizes persons with poor mental health?

    DEFF Research Database (Denmark)

    Christensen, Anne Illemann; Davidsen, Michael; Kjøller, Mette

    2014-01-01

    analysed by means of logistic regression models. Results: Men and women with poor mental health are characterized by being single, having a long-term illness, not being able to rely on help from others in case of illness and by feeling that family and friends demand too much of them. Men with poor mental...... health were further characterized by being a heavy smoker, and having a BMI below 25. Women with poor mental health were further characterized by being 16-44 years old and sedentary in leisure time. CONCLUSIONS THE PREVALENCE OF POOR MENTAL HEALTH IS HIGHER AMONG WOMEN THAN MEN, AND DIFFERENT FACTORS...... CHARACTERIZE MEN AND WOMEN WITH POOR MENTAL HEALTH THE PRESENT FINDINGS SUPPORT THE NOTION THAT BOTH SOCIO-DEMOGRAPHICS AND LIFESTYLE FACTORS ARE INDEPENDENTLY RELATED WITH POOR MENTAL HEALTH WE SUGGEST TAKING INTO ACCOUNT ALL THESE AREAS OF LIFE WHEN PLANNING ACTIVITIES TO PREVENT POOR MENTAL HEALTH AND WHEN...

  20. Global climate model performance over Alaska and Greenland

    DEFF Research Database (Denmark)

    Walsh, John E.; Chapman, William L.; Romanovsky, Vladimir

    2008-01-01

    The performance of a set of 15 global climate models used in the Coupled Model Intercomparison Project is evaluated for Alaska and Greenland, and compared with the performance over broader pan-Arctic and Northern Hemisphere extratropical domains. Root-mean-square errors relative to the 1958...... of the models are generally much larger than the biases of the composite output, indicating that the systematic errors differ considerably among the models. There is a tendency for the models with smaller errors to simulate a larger greenhouse warming over the Arctic, as well as larger increases of Arctic...... to narrowing the uncertainty and obtaining more robust estimates of future climate change in regions such as Alaska, Greenland, and the broader Arctic....

  1. Intratendon Delivery of Leukocyte-Poor Platelet-Rich Plasma Improves Healing Compared With Leukocyte-Rich Platelet-Rich Plasma in a Rabbit Achilles Tendinopathy Model.

    Science.gov (United States)

    Yan, Ruijian; Gu, Yanjia; Ran, Jisheng; Hu, Yejun; Zheng, Zefeng; Zeng, Mengfeng; Heng, Boon Chin; Chen, Xiao; Yin, Zi; Chen, Weishan; Shen, Weiliang; Ouyang, Hongwei

    2017-07-01

    Chronic tendinopathy is a commonly occurring clinical problem that affects both athletes and inactive middle-aged patients. Although some studies have shown that different platelet-rich plasma (PRP) preparations could exert various therapeutic effects in vitro, the role of leukocytes in PRP has not yet been defined under tendinopathy conditions in vivo. This study compared the effects of the intratendon delivery of leukocyte-poor PRP (Lp-PRP) versus leukocyte-rich PRP (Lr-PRP) in a rabbit chronic tendinopathy model in vivo. Controlled laboratory study. Four weeks after a local injection of collagenase in the Achilles tendon, the following treatments were randomly administered on the lesions: injections of (1) 200 μL of Lp-PRP (n = 8), (2) 200 μL of Lr-PRP (n = 8), or (3) 200 μL of saline (n = 8). Healing outcomes were assessed at 4 weeks after therapy with magnetic resonance imaging (MRI), cytokine quantification, real-time polymerase chain reaction analysis of gene expression, histology, and transmission electron microscopy (TEM). MRI revealed that the Lr-PRP and saline groups displayed higher signal intensities compared with the Lp-PRP group with T2 mapping. Histologically, the Lp-PRP group displayed significantly better general scores compared with the Lr-PRP ( P = .001) and saline ( P tendon healing and is a preferable option for the clinical treatment of tendinopathy. PRP is widely used in the clinical management of chronic tendinopathy. However, the clinical results are ambiguous. It is imperative to understand the influence of leukocytes on PRP-mediated tissue healing in vivo, which could facilitate the better clinical management of chronic tendinopathy. Further studies are needed to translate our findings to the clinical setting.

  2. Human performance modeling for system of systems analytics :soldier fatigue.

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

    2005-10-01

    The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in September 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.

  3. Performance modeling of parallel algorithms for solving neutron diffusion problems

    International Nuclear Information System (INIS)

    Azmy, Y.Y.; Kirk, B.L.

    1995-01-01

    Neutron diffusion calculations are the most common computational methods used in the design, analysis, and operation of nuclear reactors and related activities. Here, mathematical performance models are developed for the parallel algorithm used to solve the neutron diffusion equation on message passing and shared memory multiprocessors represented by the Intel iPSC/860 and the Sequent Balance 8000, respectively. The performance models are validated through several test problems, and these models are used to estimate the performance of each of the two considered architectures in situations typical of practical applications, such as fine meshes and a large number of participating processors. While message passing computers are capable of producing speedup, the parallel efficiency deteriorates rapidly as the number of processors increases. Furthermore, the speedup fails to improve appreciably for massively parallel computers so that only small- to medium-sized message passing multiprocessors offer a reasonable platform for this algorithm. In contrast, the performance model for the shared memory architecture predicts very high efficiency over a wide range of number of processors reasonable for this architecture. Furthermore, the model efficiency of the Sequent remains superior to that of the hypercube if its model parameters are adjusted to make its processors as fast as those of the iPSC/860. It is concluded that shared memory computers are better suited for this parallel algorithm than message passing computers

  4. Product Data Model for Performance-driven Design

    Science.gov (United States)

    Hu, Guang-Zhong; Xu, Xin-Jian; Xiao, Shou-Ne; Yang, Guang-Wu; Pu, Fan

    2017-09-01

    When designing large-sized complex machinery products, the design focus is always on the overall performance; however, there exist no design theory and method based on performance driven. In view of the deficiency of the existing design theory, according to the performance features of complex mechanical products, the performance indices are introduced into the traditional design theory of "Requirement-Function-Structure" to construct a new five-domain design theory of "Client Requirement-Function-Performance-Structure-Design Parameter". To support design practice based on this new theory, a product data model is established by using performance indices and the mapping relationship between them and the other four domains. When the product data model is applied to high-speed train design and combining the existing research result and relevant standards, the corresponding data model and its structure involving five domains of high-speed trains are established, which can provide technical support for studying the relationships between typical performance indices and design parameters and the fast achievement of a high-speed train scheme design. The five domains provide a reference for the design specification and evaluation criteria of high speed train and a new idea for the train's parameter design.

  5. Performance Analysis, Modeling and Scaling of HPC Applications and Tools

    Energy Technology Data Exchange (ETDEWEB)

    Bhatele, Abhinav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-13

    E cient use of supercomputers at DOE centers is vital for maximizing system throughput, mini- mizing energy costs and enabling science breakthroughs faster. This requires complementary e orts along several directions to optimize the performance of scienti c simulation codes and the under- lying runtimes and software stacks. This in turn requires providing scalable performance analysis tools and modeling techniques that can provide feedback to physicists and computer scientists developing the simulation codes and runtimes respectively. The PAMS project is using time allocations on supercomputers at ALCF, NERSC and OLCF to further the goals described above by performing research along the following fronts: 1. Scaling Study of HPC applications; 2. Evaluation of Programming Models; 3. Hardening of Performance Tools; 4. Performance Modeling of Irregular Codes; and 5. Statistical Analysis of Historical Performance Data. We are a team of computer and computational scientists funded by both DOE/NNSA and DOE/ ASCR programs such as ECRP, XStack (Traleika Glacier, PIPER), ExaOSR (ARGO), SDMAV II (MONA) and PSAAP II (XPACC). This allocation will enable us to study big data issues when analyzing performance on leadership computing class systems and to assist the HPC community in making the most e ective use of these resources.

  6. Performance of five surface energy balance models for estimating daily evapotranspiration in high biomass sorghum

    Science.gov (United States)

    Wagle, Pradeep; Bhattarai, Nishan; Gowda, Prasanna H.; Kakani, Vijaya G.

    2017-06-01

    Robust evapotranspiration (ET) models are required to predict water usage in a variety of terrestrial ecosystems under different geographical and agrometeorological conditions. As a result, several remote sensing-based surface energy balance (SEB) models have been developed to estimate ET over large regions. However, comparison of the performance of several SEB models at the same site is limited. In addition, none of the SEB models have been evaluated for their ability to predict ET in rain-fed high biomass sorghum grown for biofuel production. In this paper, we evaluated the performance of five widely used single-source SEB models, namely Surface Energy Balance Algorithm for Land (SEBAL), Mapping ET with Internalized Calibration (METRIC), Surface Energy Balance System (SEBS), Simplified Surface Energy Balance Index (S-SEBI), and operational Simplified Surface Energy Balance (SSEBop), for estimating ET over a high biomass sorghum field during the 2012 and 2013 growing seasons. The predicted ET values were compared against eddy covariance (EC) measured ET (ETEC) for 19 cloud-free Landsat image. In general, S-SEBI, SEBAL, and SEBS performed reasonably well for the study period, while METRIC and SSEBop performed poorly. All SEB models substantially overestimated ET under extremely dry conditions as they underestimated sensible heat (H) and overestimated latent heat (LE) fluxes under dry conditions during the partitioning of available energy. METRIC, SEBAL, and SEBS overestimated LE regardless of wet or dry periods. Consequently, predicted seasonal cumulative ET by METRIC, SEBAL, and SEBS were higher than seasonal cumulative ETEC in both seasons. In contrast, S-SEBI and SSEBop substantially underestimated ET under too wet conditions, and predicted seasonal cumulative ET by S-SEBI and SSEBop were lower than seasonal cumulative ETEC in the relatively wetter 2013 growing season. Our results indicate the necessity of inclusion of soil moisture or plant water stress

  7. The better model to predict and improve pediatric health care quality: performance or importance-performance?

    Science.gov (United States)

    Olsen, Rebecca M; Bryant, Carol A; McDermott, Robert J; Ortinau, David

    2013-01-01

    The perpetual search for ways to improve pediatric health care quality has resulted in a multitude of assessments and strategies; however, there is little research evidence as to their conditions for maximum effectiveness. A major reason for the lack of evaluation research and successful quality improvement initiatives is the methodological challenge of measuring quality from the parent perspective. Comparison of performance-only and importance-performance models was done to determine the better predictor of pediatric health care quality and more successful method for improving the quality of care provided to children. Fourteen pediatric health care centers serving approximately 250,000 patients in 70,000 households in three West Central Florida counties were studied. A cross-sectional design was used to determine the importance and performance of 50 pediatric health care attributes and four global assessments of pediatric health care quality. Exploratory factor analysis revealed five dimensions of care (physician care, access, customer service, timeliness of services, and health care facility). Hierarchical multiple regression compared the performance-only and the importance-performance models. In-depth interviews, participant observations, and a direct cognitive structural analysis identified 50 health care attributes included in a mailed survey to parents(n = 1,030). The tailored design method guided survey development and data collection. The importance-performance multiplicative additive model was a better predictor of pediatric health care quality. Attribute importance moderates performance and quality, making the importance-performance model superior for measuring and providing a deeper understanding of pediatric health care quality and a better method for improving the quality of care provided to children. Regardless of attribute performance, if the level of attribute importance is not taken into consideration, health care organizations may spend valuable

  8. Four-Stroke, Internal Combustion Engine Performance Modeling

    Science.gov (United States)

    Wagner, Richard C.

    In this thesis, two models of four-stroke, internal combustion engines are created and compared. The first model predicts the intake and exhaust processes using isentropic flow equations augmented by discharge coefficients. The second model predicts the intake and exhaust processes using a compressible, time-accurate, Quasi-One-Dimensional (Q1D) approach. Both models employ the same heat release and reduced-order modeling of the cylinder charge. Both include friction and cylinder loss models so that the predicted performance values can be compared to measurements. The results indicate that the isentropic-based model neglects important fluid mechanics and returns inaccurate results. The Q1D flow model, combined with the reduced-order model of the cylinder charge, is able to capture the dominant intake and exhaust fluid mechanics and produces results that compare well with measurement. Fluid friction, convective heat transfer, piston ring and skirt friction and temperature-varying specific heats in the working fluids are all shown to be significant factors in engine performance predictions. Charge blowby is shown to play a lesser role.

  9. Aircraft Anomaly Detection Using Performance Models Trained on Fleet Data

    Science.gov (United States)

    Gorinevsky, Dimitry; Matthews, Bryan L.; Martin, Rodney

    2012-01-01

    This paper describes an application of data mining technology called Distributed Fleet Monitoring (DFM) to Flight Operational Quality Assurance (FOQA) data collected from a fleet of commercial aircraft. DFM transforms the data into aircraft performance models, flight-to-flight trends, and individual flight anomalies by fitting a multi-level regression model to the data. The model represents aircraft flight performance and takes into account fixed effects: flight-to-flight and vehicle-to-vehicle variability. The regression parameters include aerodynamic coefficients and other aircraft performance parameters that are usually identified by aircraft manufacturers in flight tests. Using DFM, the multi-terabyte FOQA data set with half-million flights was processed in a few hours. The anomalies found include wrong values of competed variables, (e.g., aircraft weight), sensor failures and baises, failures, biases, and trends in flight actuators. These anomalies were missed by the existing airline monitoring of FOQA data exceedances.

  10. Model complexity and performance: How far can we simplify?

    Science.gov (United States)

    Raick, C.; Soetaert, K.; Grégoire, M.

    2006-07-01

    Handling model complexity and reliability is a key area of research today. While complex models containing sufficient detail have become possible due to increased computing power, they often lead to too much uncertainty. On the other hand, very simple models often crudely oversimplify the real ecosystem and can not be used for management purposes. Starting from a complex and validated 1D pelagic ecosystem model of the Ligurian Sea (NW Mediterranean Sea), we derived simplified aggregated models in which either the unbalanced algal growth, the functional group diversity or the explicit description of the microbial loop was sacrificed. To overcome the problem of data availability with adequate spatial and temporal resolution, the outputs of the complex model are used as the baseline of perfect knowledge to calibrate the simplified models. Objective criteria of model performance were used to compare the simplified models’ results to the complex model output and to the available data at the DYFAMED station in the central Ligurian Sea. We show that even the simplest (NPZD) model is able to represent the global ecosystem features described by the complex model (e.g. primary and secondary productions, particulate organic matter export flux, etc.). However, a certain degree of sophistication in the formulation of some biogeochemical processes is required to produce realistic behaviors (e.g. the phytoplankton competition, the potential carbon or nitrogen limitation of the zooplankton ingestion, the model trophic closure, etc.). In general, a 9 state-variable model that has the functional group diversity removed, but which retains the bacterial loop and the unbalanced algal growth, performs best.

  11. Predictors of Poor Pregnancy Outcomes Among Antenatal Care Attendees in Primary Health Care Facilities in Cross River State, Nigeria: A Multilevel Model.

    Science.gov (United States)

    Ameh, Soter; Adeleye, Omokhoa A; Kabiru, Caroline W; Agan, Thomas; Duke, Roseline; Mkpanam, Nkese; Nwoha, Doris

    2016-08-01

    Objectives Pregnancy carries a high risk for millions of women and varies by urban-rural location in Nigeria, a country with the second highest maternal deaths in the world. Addressing multilevel predictors of poor pregnancy outcomes among antenatal care (ANC) attendees in primary health care (PHC) facilities could reduce the high maternal mortality rate in Nigeria. This study utilised the "Risk Approach" strategy to (1) compare the risks of poor pregnancy outcomes among ANC attendees by urban-rural location; and (2) determine predictors of poor pregnancy outcomes among ANC attendees in urban-rural PHC facilities in Cross River State, Nigeria. Methods A cross-sectional survey was conducted in 2011 among 400 ANC attendees aged 15-49 years recruited through multistage sampling. Data on risk factors of poor pregnancy outcomes were collected using interviewer-administered questionnaires and clinic records. Respondents were categorised into low, medium or high risk of poor pregnancy outcomes, based on their overall risk scores. Predictors of poor pregnancy outcomes were determined by multilevel ordinal logistic regression. Results A greater proportion of the women in the rural areas were below the middle socio-economic quintile (75 vs. 4 %, p vs. 2 %, p vs. 35 %, p urban areas were older than 35 years (10 vs. 5 %, p care in the urban PHC facilities had a low overall risk of poor pregnancy outcomes than those in the rural facilities (64 vs. 50 %, p = 0.034). Pregnant women in the urban areas had decreased odds of being at high risk of poor pregnancy outcomes versus the combined medium and low risks compared with those in the rural areas (OR 0.55, 95 % CI 0.09-0.65). Conclusions for Practice Pregnant women attending antenatal care in rural PHC facilities are more at risk of poor pregnancy outcomes than those receiving care in the urban facilities. Health programmes that promote safe pregnancy should target pregnant women in rural settings.

  12. Thin film bulk acoustic wave devices : performance optimization and modeling

    OpenAIRE

    Pensala, Tuomas

    2011-01-01

    Thin film bulk acoustic wave (BAW) resonators and filters operating in the GHz range are used in mobile phones for the most demanding filtering applications and complement the surface acoustic wave (SAW) based filters. Their main advantages are small size and high performance at frequencies above 2 GHz. This work concentrates on the characterization, performance optimization, and modeling techniques of thin film BAW devices. Laser interferometric vibration measurements together with plat...

  13. Computational modelling of expressive music performance in hexaphonic guitar

    OpenAIRE

    Siquier, Marc

    2017-01-01

    Computational modelling of expressive music performance has been widely studied in the past. While previous work in this area has been mainly focused on classical piano music, there has been very little work on guitar music, and such work has focused on monophonic guitar playing. In this work, we present a machine learning approach to automatically generate expressive performances from non expressive music scores for polyphonic guitar. We treated guitar as an hexaphonic instrument, obtaining ...

  14. The predictive performance and stability of six species distribution models.

    Science.gov (United States)

    Duan, Ren-Yan; Kong, Xiao-Quan; Huang, Min-Yi; Fan, Wei-Yi; Wang, Zhi-Gao

    2014-01-01

    Predicting species' potential geographical range by species distribution models (SDMs) is central to understand their ecological requirements. However, the effects of using different modeling techniques need further investigation. In order to improve the prediction effect, we need to assess the predictive performance and stability of different SDMs. We collected the distribution data of five common tree species (Pinus massoniana, Betula platyphylla, Quercus wutaishanica, Quercus mongolica and Quercus variabilis) and simulated their potential distribution area using 13 environmental variables and six widely used SDMs: BIOCLIM, DOMAIN, MAHAL, RF, MAXENT, and SVM. Each model run was repeated 100 times (trials). We compared the predictive performance by testing the consistency between observations and simulated distributions and assessed the stability by the standard deviation, coefficient of variation, and the 99% confidence interval of Kappa and AUC values. The mean values of AUC and Kappa from MAHAL, RF, MAXENT, and SVM trials were similar and significantly higher than those from BIOCLIM and DOMAIN trials (pSDMs (MAHAL, RF, MAXENT, and SVM) had higher prediction accuracy, smaller confidence intervals, and were more stable and less affected by the random variable (randomly selected pseudo-absence points). According to the prediction performance and stability of SDMs, we can divide these six SDMs into two categories: a high performance and stability group including MAHAL, RF, MAXENT, and SVM, and a low performance and stability group consisting of BIOCLIM, and DOMAIN. We highlight that choosing appropriate SDMs to address a specific problem is an important part of the modeling process.

  15. Physics based performance model of a UV missile seeker

    Science.gov (United States)

    James, I.

    2017-10-01

    Electro-optically (EO) guided surface to air missiles (SAM) have developed to use Ultraviolet (UV) wavebands supplementary to the more common Infrared (IR) wavebands. Missiles such as the US Stinger have been around for some time, these have been joined recently by Chinese FN-16 and Russian SA-29 (Verba) and there is a much higher potential proliferation risk. The purpose of this paper is to introduce a first-principles, physics based, model of a typical seeker arrangement. The model is constructed from various calculations that aim to characterise the physical effects that will affect the performance of the system. Data has been gathered from a number of sources to provide realism to the variables within the model. It will be demonstrated that many of the variables have the power to dramatically alter the performance of the system as a whole. Further, data will be shown to illustrate the expected performance of a typical UV detector within a SAM in detection range against a variety of target sizes. The trend for the detection range against aircraft size and skin reflectivity will be shown to be non-linear, this should have been expected owing to the exponential decay of a signal through atmosphere. Future work will validate the performance of the model against real world performance data for cameras (when this is available) to ensure that it is operates within acceptable errors.

  16. A model to describe the performance of the UASB reactor.

    Science.gov (United States)

    Rodríguez-Gómez, Raúl; Renman, Gunno; Moreno, Luis; Liu, Longcheng

    2014-04-01

    A dynamic model to describe the performance of the Upflow Anaerobic Sludge Blanket (UASB) reactor was developed. It includes dispersion, advection, and reaction terms, as well as the resistances through which the substrate passes before its biotransformation. The UASB reactor is viewed as several continuous stirred tank reactors connected in series. The good agreement between experimental and simulated results shows that the model is able to predict the performance of the UASB reactor (i.e. substrate concentration, biomass concentration, granule size, and height of the sludge bed).

  17. PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment

    International Nuclear Information System (INIS)

    Jordan, J. M.; Flach, G. P.; Westbrook, M. L.

    2012-01-01

    Numerical simulations of groundwater flow and contaminant transport in the vadose and saturated zones have been conducted using the PORFLOW code in support of an overall Performance Assessment (PA) of the H-Tank Farm. This report provides technical detail on selected aspects of PORFLOW model development and describes the structure of the associated electronic files. The PORFLOW models for the H-Tank Farm PA, Rev. 1 were updated with grout, solubility, and inventory changes. The aquifer model was refined. In addition, a set of flow sensitivity runs were performed to allow flow to be varied in the related probabilistic GoldSim models. The final PORFLOW concentration values are used as input into a GoldSim dose calculator

  18. PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, J. M.; Flach, G. P.; Westbrook, M. L.

    2012-08-31

    Numerical simulations of groundwater flow and contaminant transport in the vadose and saturated zones have been conducted using the PORFLOW code in support of an overall Performance Assessment (PA) of the H-Tank Farm. This report provides technical detail on selected aspects of PORFLOW model development and describes the structure of the associated electronic files. The PORFLOW models for the H-Tank Farm PA, Rev. 1 were updated with grout, solubility, and inventory changes. The aquifer model was refined. In addition, a set of flow sensitivity runs were performed to allow flow to be varied in the related probabilistic GoldSim models. The final PORFLOW concentration values are used as input into a GoldSim dose calculator.

  19. Model of service-oriented catering supply chain performance evaluation

    Directory of Open Access Journals (Sweden)

    Juanqiong Gou

    2013-03-01

    Full Text Available Purpose: The aim of this paper is constructing a performance evaluation model for service-oriented catering supply chain. Design/methodology/approach: With the research on the current situation of catering industry, this paper summarized the characters of the catering supply chain, and then presents the service-oriented catering supply chain model based on the platform of logistics and information. At last, the fuzzy AHP method is used to evaluate the performance of service-oriented catering supply chain. Findings: With the analysis of the characteristics of catering supply chain, we construct the performance evaluation model in order to guarantee the food safety, logistics efficiency, price stability and so on. Practical implications: In order to evolve an efficient and effective service supply chain, it can not only used to own enterprise improvement, but also can be used for selecting different customers, to choose a different model of development. Originality/value: This paper has a new definition of service-oriented catering supply chain. And it offers a model to evaluate the performance of this catering supply chain.

  20. Aqua/Aura Updated Inclination Adjust Maneuver Performance Prediction Model

    Science.gov (United States)

    Boone, Spencer

    2017-01-01

    This presentation will discuss the updated Inclination Adjust Maneuver (IAM) performance prediction model that was developed for Aqua and Aura following the 2017 IAM series. This updated model uses statistical regression methods to identify potential long-term trends in maneuver parameters, yielding improved predictions when re-planning past maneuvers. The presentation has been reviewed and approved by Eric Moyer, ESMO Deputy Project Manager.

  1. Dynamic Experiments and Constitutive Model Performance for Polycarbonate

    Science.gov (United States)

    2014-07-01

    Storage and loss tangent moduli for PC; DMA experiments performed at 1 Hz and shift at 100 Hz showing the  and transition regions using the...author would also like to thank Dr. Adam D. Mulliken for courteously providing the experimental results and the Abaqus version of the model and...exponential factor . In 1955, the Ree-Eyring model further accounted for microstructural mechanisms by relating molecular motions to yield behavior

  2. Does segmentation always improve model performance in credit scoring?

    OpenAIRE

    Bijak, Katarzyna; Thomas, Lyn C.

    2012-01-01

    Credit scoring allows for the credit risk assessment of bank customers. A single scoring model (scorecard) can be developed for the entire customer population, e.g. using logistic regression. However, it is often expected that segmentation, i.e. dividing the population into several groups and building separate scorecards for them, will improve the model performance. The most common statistical methods for segmentation are the two-step approaches, where logistic regression follows Classificati...

  3. Building Information Modeling (BIM) for Indoor Environmental Performance Analysis

    DEFF Research Database (Denmark)

    The report is a part of a research assignment carried out by students in the 5ETCS course “Project Byggeri – [entitled as: Building Information Modeling (BIM) – Modeling & Analysis]”, during the 3rd semester of master degree in Civil and Architectural Engineering, Department of Engineering, Aarhus...... University. This includes seven papers describing BIM for Sustainability, concentrating specifically on individual topics regarding to Indoor Environment Performance Analysis....

  4. Rethinking board role performance: Towards an integrative model

    Directory of Open Access Journals (Sweden)

    Babić Verica M.

    2011-01-01

    Full Text Available This research focuses on the board role evolution analysis which took place simultaneously with the development of different corporate governance theories and perspectives. The purpose of this paper is to provide understanding of key factors that make a board effective in the performance of its role. We argue that analysis of board role performance should incorporate both structural and process variables. This paper’s contribution is the development of an integrative model that aims to establish the relationship between the board structure and processes on the one hand, and board role performance on the other.

  5. Human performance models for computer-aided engineering

    Science.gov (United States)

    Elkind, Jerome I. (Editor); Card, Stuart K. (Editor); Hochberg, Julian (Editor); Huey, Beverly Messick (Editor)

    1989-01-01

    This report discusses a topic important to the field of computational human factors: models of human performance and their use in computer-based engineering facilities for the design of complex systems. It focuses on a particular human factors design problem -- the design of cockpit systems for advanced helicopters -- and on a particular aspect of human performance -- vision and related cognitive functions. By focusing in this way, the authors were able to address the selected topics in some depth and develop findings and recommendations that they believe have application to many other aspects of human performance and to other design domains.

  6. The integration of intrapreneurship into a performance management model

    Directory of Open Access Journals (Sweden)

    Thabo WL Foba

    2007-02-01

    Full Text Available This study aimed to investigate the feasibility of using the dynamics of intrapreneurship to develop a new generation performance management model based on the structural dynamics of the Balanced Score Card approach. The literature survey covered entrepreneurship, from which the construct, intrapreneurship, was synthesized. Reconstructive logic and Hermeneutic methodology were used in studying the performance management systems and the Balanced Score Card approach. The dynamics were then integrated into a new approach for the management of performance of intrapreneurial employees in the corporate environment. An unstructured opinion survey followed: a sample of intrapreneurship students evaluated and validated the model’s conceptual feasibility and probable practical value.

  7. Model for determining and optimizing delivery performance in industrial systems

    Directory of Open Access Journals (Sweden)

    Fechete Flavia

    2017-01-01

    Full Text Available Performance means achieving organizational objectives regardless of their nature and variety, and even overcoming them. Improving performance is one of the major goals of any company. Achieving the global performance means not only obtaining the economic performance, it is a must to take into account other functions like: function of quality, delivery, costs and even the employees satisfaction. This paper aims to improve the delivery performance of an industrial system due to their very low results. The delivery performance took into account all categories of performance indicators, such as on time delivery, backlog efficiency or transport efficiency. The research was focused on optimizing the delivery performance of the industrial system, using linear programming. Modeling the delivery function using linear programming led to obtaining precise quantities to be produced and delivered each month by the industrial system in order to minimize their transport cost, satisfying their customers orders and to control their stock. The optimization led to a substantial improvement in all four performance indicators that concern deliveries.

  8. Savings for the Poor

    OpenAIRE

    Ignacio Mas

    2010-01-01

    This paper reviews the relevance of formal financial services – in particular, savings – to poor people, the economic factors that have hindered the mass-scale delivery of such services in developing countries, and the technology-based opportunities that exist today to make massive gains in financial inclusion. It also highlights the benefits to government from universal financial access, as well as the key policy enablers that would need to be put in place to allow the necessary innovati...

  9. Reference Manual for the System Advisor Model's Wind Power Performance Model

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, J.; Jorgenson, J.; Gilman, P.; Ferguson, T.

    2014-08-01

    This manual describes the National Renewable Energy Laboratory's System Advisor Model (SAM) wind power performance model. The model calculates the hourly electrical output of a single wind turbine or of a wind farm. The wind power performance model requires information about the wind resource, wind turbine specifications, wind farm layout (if applicable), and costs. In SAM, the performance model can be coupled to one of the financial models to calculate economic metrics for residential, commercial, or utility-scale wind projects. This manual describes the algorithms used by the wind power performance model, which is available in the SAM user interface and as part of the SAM Simulation Core (SSC) library, and is intended to supplement the user documentation that comes with the software.

  10. Spatial variability and parametric uncertainty in performance assessment models

    International Nuclear Information System (INIS)

    Pensado, Osvaldo; Mancillas, James; Painter, Scott; Tomishima, Yasuo

    2011-01-01

    The problem of defining an appropriate treatment of distribution functions (which could represent spatial variability or parametric uncertainty) is examined based on a generic performance assessment model for a high-level waste repository. The generic model incorporated source term models available in GoldSim ® , the TDRW code for contaminant transport in sparse fracture networks with a complex fracture-matrix interaction process, and a biosphere dose model known as BDOSE TM . Using the GoldSim framework, several Monte Carlo sampling approaches and transport conceptualizations were evaluated to explore the effect of various treatments of spatial variability and parametric uncertainty on dose estimates. Results from a model employing a representative source and ensemble-averaged pathway properties were compared to results from a model allowing for stochastic variation of transport properties along streamline segments (i.e., explicit representation of spatial variability within a Monte Carlo realization). We concluded that the sampling approach and the definition of an ensemble representative do influence consequence estimates. In the examples analyzed in this paper, approaches considering limited variability of a transport resistance parameter along a streamline increased the frequency of fast pathways resulting in relatively high dose estimates, while those allowing for broad variability along streamlines increased the frequency of 'bottlenecks' reducing dose estimates. On this basis, simplified approaches with limited consideration of variability may suffice for intended uses of the performance assessment model, such as evaluation of site safety. (author)

  11. A model of CCTV surveillance operator performance | Donald ...

    African Journals Online (AJOL)

    cognitive processes involved in visual search and monitoring – key activities of operators. The aim of this paper was to integrate the factors into a holistic theoretical model of performance for CCTV operators, drawing on areas such as vigilance, ...

  12. Models for the financial-performance effects of Marketing

    NARCIS (Netherlands)

    Hanssens, D.M.; Dekimpe, Marnik; Wierenga, B.; van der Lans, R.

    We consider marketing-mix models that explicitly include financial performance criteria. These financial metrics are not only comparable across the marketing mix, they also relate well to investors’ evaluation of the firm. To that extent, we treat marketing as an investment in customer value

  13. Modeling performance measurement applications and implementation issues in DEA

    CERN Document Server

    Cook, Wade D

    2005-01-01

    Addresses advanced/new DEA methodology and techniques that are developed for modeling unique and new performance evaluation issuesPesents new DEA methodology and techniques via discussions on how to solve managerial problemsProvides an easy-to-use DEA software - DEAFrontier (www.deafrontier.com) which is an excellent tool for both DEA researchers and practitioners.

  14. Performances of estimators of linear auto-correlated error model ...

    African Journals Online (AJOL)

    The performances of five estimators of linear models with autocorrelated disturbance terms are compared when the independent variable is exponential. The results reveal that for both small and large samples, the Ordinary Least Squares (OLS) compares favourably with the Generalized least Squares (GLS) estimators in ...

  15. Towards a Social Networks Model for Online Learning & Performance

    Science.gov (United States)

    Chung, Kon Shing Kenneth; Paredes, Walter Christian

    2015-01-01

    In this study, we develop a theoretical model to investigate the association between social network properties, "content richness" (CR) in academic learning discourse, and performance. CR is the extent to which one contributes content that is meaningful, insightful and constructive to aid learning and by social network properties we…

  16. Quantitative modeling of human performance in complex, dynamic systems

    National Research Council Canada - National Science Library

    Baron, Sheldon; Kruser, Dana S; Huey, Beverly Messick

    1990-01-01

    ... Sheldon Baron, Dana S. Kruser, and Beverly Messick Huey, editors Panel on Human Performance Modeling Committee on Human Factors Commission on Behavioral and Social Sciences and Education National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1990 Copyrightoriginal retained, the be not from cannot book, paper original however, for version forma...

  17. Performances Of Estimators Of Linear Models With Autocorrelated ...

    African Journals Online (AJOL)

    The performances of five estimators of linear models with Autocorrelated error terms are compared when the independent variable is autoregressive. The results reveal that the properties of the estimators when the sample size is finite is quite similar to the properties of the estimators when the sample size is infinite although ...

  18. Performances of estimators of linear model with auto-correlated ...

    African Journals Online (AJOL)

    Performances of estimators of linear model with auto-correlated error terms when the independent variable is normal. ... On the other hand, the same slope coefficients β , under Generalized Least Squares (GLS) decreased with increased autocorrelation when the sample size T is small. Journal of the Nigerian Association ...

  19. Performance Modeling for Heterogeneous Wireless Networks with Multiservice Overflow Traffic

    DEFF Research Database (Denmark)

    Huang, Qian; Ko, King-Tim; Iversen, Villy Bæk

    2009-01-01

    . Multiservice loss analysis based on multi-dimensional Markov chain becomes intractable in these networks due to intensive computations required. This paper focuses on performance modeling for heterogeneous wireless networks based on a hierarchical overlay infrastructure. A method based on decomposition...

  20. Stutter-Step Models of Performance in School

    Science.gov (United States)

    Morgan, Stephen L.; Leenman, Theodore S.; Todd, Jennifer J.; Kentucky; Weeden, Kim A.

    2013-01-01

    To evaluate a stutter-step model of academic performance in high school, this article adopts a unique measure of the beliefs of 12,591 high school sophomores from the Education Longitudinal Study, 2002-2006. Verbatim responses to questions on occupational plans are coded to capture specific job titles, the listing of multiple jobs, and the listing…

  1. Performance in model transformations: experiments with ATL and QVT

    NARCIS (Netherlands)

    van Amstel, Marcel; Bosems, S.; Ivanov, Ivan; Ferreira Pires, Luis; Cabot, Jordi; Visser, Eelco

    Model transformations are increasingly being incorporated in software development processes. However, as systems being developed with transformations grow in size and complexity, the performance of the transformations tends to degrade. In this paper we investigate the factors that have an impact on

  2. Modelling of green roof hydrological performance for urban drainage applications

    DEFF Research Database (Denmark)

    Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen

    2014-01-01

    Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes...... surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data...... from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010–2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989...

  3. Multiscale Modeling and Uncertainty Quantification for Nuclear Fuel Performance

    Energy Technology Data Exchange (ETDEWEB)

    Estep, Donald [Colorado State Univ., Fort Collins, CO (United States); El-Azab, Anter [Florida State Univ., Tallahassee, FL (United States); Pernice, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Peterson, John W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Polyakov, Peter [Univ. of Wyoming, Laramie, WY (United States); Tavener, Simon [Colorado State Univ., Fort Collins, CO (United States); Xiu, Dongbin [Purdue Univ., West Lafayette, IN (United States); Univ. of Utah, Salt Lake City, UT (United States)

    2017-03-23

    In this project, we will address the challenges associated with constructing high fidelity multiscale models of nuclear fuel performance. We (*) propose a novel approach for coupling mesoscale and macroscale models, (*) devise efficient numerical methods for simulating the coupled system, and (*) devise and analyze effective numerical approaches for error and uncertainty quantification for the coupled multiscale system. As an integral part of the project, we will carry out analysis of the effects of upscaling and downscaling, investigate efficient methods for stochastic sensitivity analysis of the individual macroscale and mesoscale models, and carry out a posteriori error analysis for computed results. We will pursue development and implementation of solutions in software used at Idaho National Laboratories on models of interest to the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program.

  4. Performance of GeantV EM Physics Models

    Science.gov (United States)

    Amadio, G.; Ananya, A.; Apostolakis, J.; Aurora, A.; Bandieramonte, M.; Bhattacharyya, A.; Bianchini, C.; Brun, R.; Canal, P.; Carminati, F.; Cosmo, G.; Duhem, L.; Elvira, D.; Folger, G.; Gheata, A.; Gheata, M.; Goulas, I.; Iope, R.; Jun, S. Y.; Lima, G.; Mohanty, A.; Nikitina, T.; Novak, M.; Pokorski, W.; Ribon, A.; Seghal, R.; Shadura, O.; Vallecorsa, S.; Wenzel, S.; Zhang, Y.

    2017-10-01

    The recent progress in parallel hardware architectures with deeper vector pipelines or many-cores technologies brings opportunities for HEP experiments to take advantage of SIMD and SIMT computing models. Launched in 2013, the GeantV project studies performance gains in propagating multiple particles in parallel, improving instruction throughput and data locality in HEP event simulation on modern parallel hardware architecture. Due to the complexity of geometry description and physics algorithms of a typical HEP application, performance analysis is indispensable in identifying factors limiting parallel execution. In this report, we will present design considerations and preliminary computing performance of GeantV physics models on coprocessors (Intel Xeon Phi and NVidia GPUs) as well as on mainstream CPUs.

  5. Performance modelling for product development of advanced window systems

    DEFF Research Database (Denmark)

    Appelfeld, David

    The research presented in this doctoral thesis shows how the product development (PD) of Complex Fenestration Systems (CFSs) can be facilitated by computer-based analysis to improve the energy efficiency of fenestration systems as well as to improve the indoor environment. The first chapter defines...... and methods,which can address interrelated performance parameters of CFS, are sought. It is possible to evaluate such systems by measurements, however the high cost and complexity of the measurements are limiting factors. The studies in this thesis confirmed that the results from the performance measurements...... of CFSs can be interpreted by simulations and hence simulations can be used for the performance analysis of new CFSs. An advanced simulation model must be often developed and needs to be validated by measurements before the model can be reused. The validation of simulations against the measurements proved...

  6. Modeling the seakeeping performance of luxury cruise ships

    Science.gov (United States)

    Cao, Yu; Yu, Bao-Jun; Wang, Jian-Fang

    2010-09-01

    The seakeeping performance of a luxury cruise ship was evaluated during the concept design phase. By comparing numerical predictions based on 3-D linear potential flow theory in the frequency domain with the results of model tests, it was shown that the 3-D method predicted the seakeeping performance of the luxury cruise ship well. Based on the model, the seakeeping features of the luxury cruise ship were analyzed, and then the influence was seen of changes to the primary design parameters (center of gravity, inertial radius, etc.). Based on the results, suggestions were proposed to improve the choice of parameters for luxury cruise ships during the concept design phase. They should improve seakeeping performance.

  7. Performance Models and Risk Management in Communications Systems

    CERN Document Server

    Harrison, Peter; Rüstem, Berç

    2011-01-01

    This volume covers recent developments in the design, operation, and management of telecommunication and computer network systems in performance engineering and addresses issues of uncertainty, robustness, and risk. Uncertainty regarding loading and system parameters leads to challenging optimization and robustness issues. Stochastic modeling combined with optimization theory ensures the optimum end-to-end performance of telecommunication or computer network systems. In view of the diverse design options possible, supporting models have many adjustable parameters and choosing the best set for a particular performance objective is delicate and time-consuming. An optimization based approach determines the optimal possible allocation for these parameters. Researchers and graduate students working at the interface of telecommunications and operations research will benefit from this book. Due to the practical approach, this book will also serve as a reference tool for scientists and engineers in telecommunication ...

  8. Performance of GeantV EM Physics Models

    CERN Document Server

    Amadio, G; Apostolakis, J; Aurora, A; Bandieramonte, M; Bhattacharyya, A; Bianchini, C; Brun, R; Canal P; Carminati, F; Cosmo, G; Duhem, L; Elvira, D; Folger, G; Gheata, A; Gheata, M; Goulas, I; Iope, R; Jun, S Y; Lima, G; Mohanty, A; Nikitina, T; Novak, M; Pokorski, W; Ribon, A; Seghal, R; Shadura, O; Vallecorsa, S; Wenzel, S; Zhang, Y

    2017-01-01

    The recent progress in parallel hardware architectures with deeper vector pipelines or many-cores technologies brings opportunities for HEP experiments to take advantage of SIMD and SIMT computing models. Launched in 2013, the GeantV project studies performance gains in propagating multiple particles in parallel, improving instruction throughput and data locality in HEP event simulation on modern parallel hardware architecture. Due to the complexity of geometry description and physics algorithms of a typical HEP application, performance analysis is indispensable in identifying factors limiting parallel execution. In this report, we will present design considerations and preliminary computing performance of GeantV physics models on coprocessors (Intel Xeon Phi and NVidia GPUs) as well as on mainstream CPUs.

  9. Performance of GeantV EM Physics Models

    Energy Technology Data Exchange (ETDEWEB)

    Amadio, G.; et al.

    2016-10-14

    The recent progress in parallel hardware architectures with deeper vector pipelines or many-cores technologies brings opportunities for HEP experiments to take advantage of SIMD and SIMT computing models. Launched in 2013, the GeantV project studies performance gains in propagating multiple particles in parallel, improving instruction throughput and data locality in HEP event simulation on modern parallel hardware architecture. Due to the complexity of geometry description and physics algorithms of a typical HEP application, performance analysis is indispensable in identifying factors limiting parallel execution. In this report, we will present design considerations and preliminary computing performance of GeantV physics models on coprocessors (Intel Xeon Phi and NVidia GPUs) as well as on mainstream CPUs.

  10. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    Science.gov (United States)

    Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

    2014-01-01

    This paper presents recent thermal model results of the Advanced Stirling Radioisotope Generator (ASRG). The three-dimensional (3D) ASRG thermal power model was built using the Thermal Desktop(trademark) thermal analyzer. The model was correlated with ASRG engineering unit test data and ASRG flight unit predictions from Lockheed Martin's (LM's) I-deas(trademark) TMG thermal model. The auxiliary cooling system (ACS) of the ASRG is also included in the ASRG thermal model. The ACS is designed to remove waste heat from the ASRG so that it can be used to heat spacecraft components. The performance of the ACS is reported under nominal conditions and during a Venus flyby scenario. The results for the nominal case are validated with data from Lockheed Martin. Transient thermal analysis results of ASRG for a Venus flyby with a representative trajectory are also presented. In addition, model results of an ASRG mounted on a Cassini-like spacecraft with a sunshade are presented to show a way to mitigate the high temperatures of a Venus flyby. It was predicted that the sunshade can lower the temperature of the ASRG alternator by 20 C for the representative Venus flyby trajectory. The 3D model also was modified to predict generator performance after a single Advanced Stirling Convertor failure. The geometry of the Microtherm HT insulation block on the outboard side was modified to match deformation and shrinkage observed during testing of a prototypic ASRG test fixture by LM. Test conditions and test data were used to correlate the model by adjusting the thermal conductivity of the deformed insulation to match the post-heat-dump steady state temperatures. Results for these conditions showed that the performance of the still-functioning inboard ACS was unaffected.

  11. A PERFORMANCE MANAGEMENT MODEL FOR PHYSICAL ASSET MANAGEMENT

    Directory of Open Access Journals (Sweden)

    J.L. Jooste

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: There has been an emphasis shift from maintenance management towards asset management, where the focus is on reliable and operational equipment and on effective assets at optimum life-cycle costs. A challenge in the manufacturing industry is to develop an asset performance management model that is integrated with business processes and strategies. The authors developed the APM2 model to satisfy that requirement. The model has a generic reference structure and is supported by operational protocols to assist in operations management. It facilitates performance measurement, business integration and continuous improvement, whilst exposing industry to the latest developments in asset performance management.

    AFRIKAANSE OPSOMMING: Daar is ‘n klemverskuiwing vanaf onderhoudsbestuur na batebestuur, waar daar gefokus word op betroubare en operasionele toerusting, asook effektiewe bates teen optimum lewensikluskoste. ‘n Uitdaging in die vervaardigingsindustrie is die ontwikkeling van ‘n prestasiemodel vir bates, wat geïntegreer is met besigheidsprosesse en –strategieë. Die outeurs het die APM2 model ontwikkel om in hierdie behoefte te voorsien. Die model het ‘n generiese verwysingsstruktuur, wat ondersteun word deur operasionele instruksies wat operasionele bestuur bevorder. Dit fasiliteer prestasiebestuur, besigheidsintegrasie en voortdurende verbetering, terwyl dit die industrie ook blootstel aan die nuutste ontwikkelinge in prestasiebestuur van bates.

  12. Aerodynamic drag modeling of alpine skiers performing giant slalom turns.

    Science.gov (United States)

    Meyer, Frédéric; Le Pelley, David; Borrani, Fabio

    2012-06-01

    Aerodynamic drag plays an important role in performance for athletes practicing sports that involve high-velocity motions. In giant slalom, the skier is continuously changing his/her body posture, and this affects the energy dissipated in aerodynamic drag. It is therefore important to quantify this energy to understand the dynamic behavior of the skier. The aims of this study were to model the aerodynamic drag of alpine skiers in giant slalom simulated conditions and to apply these models in a field experiment to estimate energy dissipated through aerodynamic drag. The aerodynamic characteristics of 15 recreational male and female skiers were measured in a wind tunnel while holding nine different skiing-specific postures. The drag and the frontal area were recorded simultaneously for each posture. Four generalized and two individualized models of the drag coefficient were built, using different sets of parameters. These models were subsequently applied in a field study designed to compare the aerodynamic energy losses between a dynamic and a compact skiing technique. The generalized models estimated aerodynamic drag with an accuracy of between 11.00% and 14.28%, and the individualized models estimated aerodynamic drag with an accuracy between 4.52% and 5.30%. The individualized model used for the field study showed that using a dynamic technique led to 10% more aerodynamic drag energy loss than using a compact technique. The individualized models were capable of discriminating different techniques performed by advanced skiers and seemed more accurate than the generalized models. The models presented here offer a simple yet accurate method to estimate the aerodynamic drag acting upon alpine skiers while rapidly moving through the range of positions typical to turning technique.

  13. Performance model for telehealth use in home health agencies.

    Science.gov (United States)

    Frey, Jocelyn; Harmonosky, Catherine M; Dansky, Kathryn H

    2005-10-01

    Increasingly, home health agencies (HHAs) are considering the value of implementing telehealth technology. However, questions arise concerning how to manage and use this technology to benefit patients, nurses, and the agency. Performance models will be beneficial to managers and decision makers in the home health field by providing quantitative information for present and future planning of staff and technology usage in the HHA. This paper presents a model that predicts the average daily census of the HHA as a function of statistically identified parameters. Average daily census was chosen as the outcome variable because it is a proxy measure of an agency's capacity. The model suggests that including a telehealth system in the HHA increases average daily census by 40%-90% depending on the number of nurse full-time equivalent(s) (FTEs) and amount of travel hours per month. The use of a home telecare system enhances HHA performance.

  14. PHARAO laser source flight model: Design and performances

    Energy Technology Data Exchange (ETDEWEB)

    Lévèque, T., E-mail: thomas.leveque@cnes.fr; Faure, B.; Esnault, F. X.; Delaroche, C.; Massonnet, D.; Grosjean, O.; Buffe, F.; Torresi, P. [Centre National d’Etudes Spatiales, 18 avenue Edouard Belin, 31400 Toulouse (France); Bomer, T.; Pichon, A.; Béraud, P.; Lelay, J. P.; Thomin, S. [Sodern, 20 Avenue Descartes, 94451 Limeil-Brévannes (France); Laurent, Ph. [LNE-SYRTE, CNRS, UPMC, Observatoire de Paris, 61 avenue de l’Observatoire, 75014 Paris (France)

    2015-03-15

    In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature, and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.

  15. Ergonomic evaluation model of operational room based on team performance

    Directory of Open Access Journals (Sweden)

    YANG Zhiyi

    2017-05-01

    Full Text Available A theoretical calculation model based on the ergonomic evaluation of team performance was proposed in order to carry out the ergonomic evaluation of the layout design schemes of the action station in a multitasking operational room. This model was constructed in order to calculate and compare the theoretical value of team performance in multiple layout schemes by considering such substantial influential factors as frequency of communication, distance, angle, importance, human cognitive characteristics and so on. An experiment was finally conducted to verify the proposed model under the criteria of completion time and accuracy rating. As illustrated by the experiment results,the proposed approach is conductive to the prediction and ergonomic evaluation of the layout design schemes of the action station during early design stages,and provides a new theoretical method for the ergonomic evaluation,selection and optimization design of layout design schemes.

  16. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    Science.gov (United States)

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  17. Measuring broadband in Europe: : development of a market model and performance index using structural equations modelling

    NARCIS (Netherlands)

    Lemstra, W.; Voogt, B.; Gorp, van N.

    2015-01-01

    This contribution reports on the development of a performance index and underlying market model with application to broadband developments in the European Union. The Structure–Conduct–Performance paradigm provides the theoretical grounding. Structural equations modelling was applied to determine the

  18. A performance model for the communication in fast multipole methods on high-performance computing platforms

    KAUST Repository

    Ibeid, Huda

    2016-03-04

    Exascale systems are predicted to have approximately 1 billion cores, assuming gigahertz cores. Limitations on affordable network topologies for distributed memory systems of such massive scale bring new challenges to the currently dominant parallel programing model. Currently, there are many efforts to evaluate the hardware and software bottlenecks of exascale designs. It is therefore of interest to model application performance and to understand what changes need to be made to ensure extrapolated scalability. The fast multipole method (FMM) was originally developed for accelerating N-body problems in astrophysics and molecular dynamics but has recently been extended to a wider range of problems. Its high arithmetic intensity combined with its linear complexity and asynchronous communication patterns make it a promising algorithm for exascale systems. In this paper, we discuss the challenges for FMM on current parallel computers and future exascale architectures, with a focus on internode communication. We focus on the communication part only; the efficiency of the computational kernels are beyond the scope of the present study. We develop a performance model that considers the communication patterns of the FMM and observe a good match between our model and the actual communication time on four high-performance computing (HPC) systems, when latency, bandwidth, network topology, and multicore penalties are all taken into account. To our knowledge, this is the first formal characterization of internode communication in FMM that validates the model against actual measurements of communication time. The ultimate communication model is predictive in an absolute sense; however, on complex systems, this objective is often out of reach or of a difficulty out of proportion to its benefit when there exists a simpler model that is inexpensive and sufficient to guide coding decisions leading to improved scaling. The current model provides such guidance.

  19. A New Model to Simulate Energy Performance of VRF Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Tianzhen; Pang, Xiufeng; Schetrit, Oren; Wang, Liping; Kasahara, Shinichi; Yura, Yoshinori; Hinokuma, Ryohei

    2014-03-30

    This paper presents a new model to simulate energy performance of variable refrigerant flow (VRF) systems in heat pump operation mode (either cooling or heating is provided but not simultaneously). The main improvement of the new model is the introduction of the evaporating and condensing temperature in the indoor and outdoor unit capacity modifier functions. The independent variables in the capacity modifier functions of the existing VRF model in EnergyPlus are mainly room wet-bulb temperature and outdoor dry-bulb temperature in cooling mode and room dry-bulb temperature and outdoor wet-bulb temperature in heating mode. The new approach allows compliance with different specifications of each indoor unit so that the modeling accuracy is improved. The new VRF model was implemented in a custom version of EnergyPlus 7.2. This paper first describes the algorithm for the new VRF model, which is then used to simulate the energy performance of a VRF system in a Prototype House in California that complies with the requirements of Title 24 ? the California Building Energy Efficiency Standards. The VRF system performance is then compared with three other types of HVAC systems: the Title 24-2005 Baseline system, the traditional High Efficiency system, and the EnergyStar Heat Pump system in three typical California climates: Sunnyvale, Pasadena and Fresno. Calculated energy savings from the VRF systems are significant. The HVAC site energy savings range from 51 to 85percent, while the TDV (Time Dependent Valuation) energy savings range from 31 to 66percent compared to the Title 24 Baseline Systems across the three climates. The largest energy savings are in Fresno climate followed by Sunnyvale and Pasadena. The paper discusses various characteristics of the VRF systems contributing to the energy savings. It should be noted that these savings are calculated using the Title 24 prototype House D under standard operating conditions. Actual performance of the VRF systems for real

  20. A conceptual model to improve performance in virtual teams

    Directory of Open Access Journals (Sweden)

    Shopee Dube

    2016-09-01

    Full Text Available Background: The vast improvement in communication technologies and sophisticated project management tools, methods and techniques has allowed geographically and culturally diverse groups to operate and function in a virtual environment. To succeed in this virtual environment where time and space are becoming increasingly irrelevant, organisations must define new ways of implementing initiatives. This virtual environment phenomenon has brought about the formation of virtual project teams that allow organisations to harness the skills and knowhow of the best resources, irrespective of their location. Objectives: The aim of this article was to investigate performance criteria and develop a conceptual model which can be applied to enhance the success of virtual project teams. There are no clear guidelines of the performance criteria in managing virtual project teams. Method: A qualitative research methodology was used in this article. The purpose of content analysis was to explore the literature to understand the concept of performance in virtual project teams and to summarise the findings of the literature reviewed. Results: The research identified a set of performance criteria for the virtual project teams as follows: leadership, trust, communication, team cooperation, reliability, motivation, comfort and social interaction. These were used to conceptualise the model. Conclusion: The conceptual model can be used in a holistic way to determine the overall performance of the virtual project team, but each factor can be analysed individually to determine the impact on the overall performance. The knowledge of performance criteria for virtual project teams could aid project managers in enhancing the success of these teams and taking a different approach to better manage and coordinate them.

  1. Outdoor FSO Communications Under Fog: Attenuation Modeling and Performance Evaluation

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-18

    Fog is considered to be a primary challenge for free space optics (FSO) systems. It may cause attenuation that is up to hundreds of decibels per kilometer. Hence, accurate modeling of fog attenuation will help telecommunication operators to engineer and appropriately manage their networks. In this paper, we examine fog measurement data coming from several locations in Europe and the United States and derive a unified channel attenuation model. Compared with existing attenuation models, our proposed model achieves a minimum of 9 dB, which is lower than the average root-mean-square error (RMSE). Moreover, we have investigated the statistical behavior of the channel and developed a probabilistic model under stochastic fog conditions. Furthermore, we studied the performance of the FSO system addressing various performance metrics, including signal-to-noise ratio (SNR), bit-error rate (BER), and channel capacity. Our results show that in communication environments with frequent fog, FSO is typically a short-range data transmission technology. Therefore, FSO will have its preferred market segment in future wireless fifth-generation/sixth-generation (5G/6G) networks having cell sizes that are lower than a 1-km diameter. Moreover, the results of our modeling and analysis can be applied in determining the switching/thresholding conditions in highly reliable hybrid FSO/radio-frequency (RF) networks.

  2. Effect of Using Extreme Years in Hydrologic Model Calibration Performance

    Science.gov (United States)

    Goktas, R. K.; Tezel, U.; Kargi, P. G.; Ayvaz, T.; Tezyapar, I.; Mesta, B.; Kentel, E.

    2017-12-01

    Hydrological models are useful in predicting and developing management strategies for controlling the system behaviour. Specifically they can be used for evaluating streamflow at ungaged catchments, effect of climate change, best management practices on water resources, or identification of pollution sources in a watershed. This study is a part of a TUBITAK project named "Development of a geographical information system based decision-making tool for water quality management of Ergene Watershed using pollutant fingerprints". Within the scope of this project, first water resources in Ergene Watershed is studied. Streamgages found in the basin are identified and daily streamflow measurements are obtained from State Hydraulic Works of Turkey. Streamflow data is analysed using box-whisker plots, hydrographs and flow-duration curves focusing on identification of extreme periods, dry or wet. Then a hydrological model is developed for Ergene Watershed using HEC-HMS in the Watershed Modeling System (WMS) environment. The model is calibrated for various time periods including dry and wet ones and the performance of calibration is evaluated using Nash-Sutcliffe Efficiency (NSE), correlation coefficient, percent bias (PBIAS) and root mean square error. It is observed that calibration period affects the model performance, and the main purpose of the development of the hydrological model should guide calibration period selection. Acknowledgement: This study is funded by The Scientific and Technological Research Council of Turkey (TUBITAK) under Project Number 115Y064.

  3. The Network Performance Assessment Model - Regulation with a Reference Network

    International Nuclear Information System (INIS)

    Larsson, Mats B.O.

    2003-11-01

    A new model - the Network Performance Assessment Model - has been developed gradually since 1998, in order to evaluate and benchmark local electricity grids. The model is intended to be a regulation tool for the Swedish local electricity networks, used by the Swedish Energy Agency. At spring 2004 the Network Performance Assessment Model will run into operation, based on the companies' results for 2003. The mission of the Network Performance Assessment Model is to evaluate the networks from a costumers' point of view and establish a fair price level. In order to do that, the performance of the operator is evaluated. The performances are assessed in correspondence to a price level that the consumer is considered to accept, can agree to as fair and is prepared to pay. This price level is based on an average cost, based on the cost of an efficient grid that will be built today, with already known technology. The performances are accounted in Customer Values. Those Customer Values are what can be created by someone but can't be created better by someone else. The starting point is to look upon the companies from a customers' point of view. The factors that can't be influenced by the companies are evaluated by fixed rules, valid to all companies. The rules reflect the differences. The cost for a connection is evaluated from the actual facts, i.e. the distances between the subscribers and the demanded capacity by the subscriber. This is done by the creation of a reference network, with a capacity to fulfill the demand from the subscriber. This is an efficient grid with no spare capacity and no excess capacity. The companies' existing grid are without importance, as well as holds for dimensioning as technology. Those factors which the company can influence, for an example connection reliability, are evaluated from a customer perspective by measuring the actual reliability, measured as the number and length of the interruption. When implemented to the regulation the Network

  4. The performance of different models of primary care provision in Southern Africa.

    Science.gov (United States)

    Mills, Anne; Palmer, Natasha; Gilson, Lucy; McIntyre, Di; Schneider, Helen; Sinanovic, Edina; Wadee, Haroon

    2004-09-01

    Despite the emphasis placed during the last two decades on public delivery of comprehensive and equitable primary care (PC) to developing country populations, coverage remains far from universal and the quality often poor. Users frequently patronise private providers, ranging from informal drug sellers to trained professionals. Interest is increasing internationally in the potential for making better use of private providers, including contractual approaches. The research aim was to examine the performance of different models of PC provision, in order to identify their strengths and weaknesses from the perspective of a government wishing to develop an overall strategy for improving PC provision. Models evaluated were: (a) South African general practitioners (district surgeons) providing services under public contracts; (b) clinics provided in Lesotho under a sub-contract between a construction company and a South African health care company; (c) GP services provided through an Independent Practitioner Association to low income insured workers and families; (d) a private clinic chain serving low income insured and uninsured workers and their families; and (e) for comparative purposes, South African public clinics. Performance was analysed in terms of provider cost and quality (of infrastructure, treatment practices, acceptability to patients and communities), allowing for differences in services and case-mix. The diversity of the arrangements made direct comparisons difficult, however, clear differences were identified between the models and conclusions drawn on their relative performance and the influences upon performance. The study findings demonstrate that contextual features strongly influence provider performance, and that a crude public/private comparison is not helpful. Key issues in contract design likely to influence performance are highlighted. Finally, the study argues that there is a need before contracting out service provision to consider how the

  5. Synthesised model of market orientation-business performance relationship

    Directory of Open Access Journals (Sweden)

    G. Nwokah

    2006-12-01

    Full Text Available Purpose: The purpose of this paper is to assess the impact of market orientation on the performance of the organisation. While much empirical works have centered on market orientation, the generalisability of its impact on performance of the Food and Beverages organisations in the Nigeria context has been under-researched. Design/Methodology/Approach: The study adopted a triangulation methodology (quantitative and qualitative approach. Data was collected from key informants using a research instrument. Returned instruments were analyzed using nonparametric correlation through the use of the Statistical Package for Social Sciences (SPSS version 10. Findings: The study validated the earlier instruments but did not find any strong association between market orientation and business performance in the Nigerian context using the food and beverages organisations for the study. The reasons underlying the weak relationship between market orientation and business performance of the Food and Beverages organisations is government policies, new product development, diversification, innovation and devaluation of the Nigerian currency. One important finding of this study is that market orientation leads to business performance through some moderating variables. Implications: The study recommends that Nigerian Government should ensure a stable economy and make economic policies that will enhance existing business development in the country. Also, organisations should have performance measurement systems to detect the impact of investment on market orientation with the aim of knowing how the organisation works. Originality/Value: This study significantly refines the body of knowledge concerning the impact of market orientation on the performance of the organisation, and thereby offers a model of market orientation and business performance in the Nigerian context for marketing scholars and practitioners. This model will, no doubt, contribute to the body of

  6. Radionuclide release rates from spent fuel for performance assessment modeling

    International Nuclear Information System (INIS)

    Curtis, D.B.

    1994-01-01

    In a scenario of aqueous transport from a high-level radioactive waste repository, the concentration of radionuclides in water in contact with the waste constitutes the source term for transport models, and as such represents a fundamental component of all performance assessment models. Many laboratory experiments have been done to characterize release rates and understand processes influencing radionuclide release rates from irradiated nuclear fuel. Natural analogues of these waste forms have been studied to obtain information regarding the long-term stability of potential waste forms in complex natural systems. This information from diverse sources must be brought together to develop and defend methods used to define source terms for performance assessment models. In this manuscript examples of measures of radionuclide release rates from spent nuclear fuel or analogues of nuclear fuel are presented. Each example represents a very different approach to obtaining a numerical measure and each has its limitations. There is no way to obtain an unambiguous measure of this or any parameter used in performance assessment codes for evaluating the effects of processes operative over many millennia. The examples are intended to suggest by example that in the absence of the ability to evaluate accuracy and precision, consistency of a broadly based set of data can be used as circumstantial evidence to defend the choice of parameters used in performance assessments

  7. Integrated modeling tool for performance engineering of complex computer systems

    Science.gov (United States)

    Wright, Gary; Ball, Duane; Hoyt, Susan; Steele, Oscar

    1989-01-01

    This report summarizes Advanced System Technologies' accomplishments on the Phase 2 SBIR contract NAS7-995. The technical objectives of the report are: (1) to develop an evaluation version of a graphical, integrated modeling language according to the specification resulting from the Phase 2 research; and (2) to determine the degree to which the language meets its objectives by evaluating ease of use, utility of two sets of performance predictions, and the power of the language constructs. The technical approach followed to meet these objectives was to design, develop, and test an evaluation prototype of a graphical, performance prediction tool. The utility of the prototype was then evaluated by applying it to a variety of test cases found in the literature and in AST case histories. Numerous models were constructed and successfully tested. The major conclusion of this Phase 2 SBIR research and development effort is that complex, real-time computer systems can be specified in a non-procedural manner using combinations of icons, windows, menus, and dialogs. Such a specification technique provides an interface that system designers and architects find natural and easy to use. In addition, PEDESTAL's multiview approach provides system engineers with the capability to perform the trade-offs necessary to produce a design that meets timing performance requirements. Sample system designs analyzed during the development effort showed that models could be constructed in a fraction of the time required by non-visual system design capture tools.

  8. Performance of neutron kinetics models for ADS transient analyses

    International Nuclear Information System (INIS)

    Rineiski, A.; Maschek, W.; Rimpault, G.

    2002-01-01

    Within the framework of the SIMMER code development, neutron kinetics models for simulating transients and hypothetical accidents in advanced reactor systems, in particular in Accelerator Driven Systems (ADSs), have been developed at FZK/IKET in cooperation with CE Cadarache. SIMMER is a fluid-dynamics/thermal-hydraulics code, coupled with a structure model and a space-, time- and energy-dependent neutronics module for analyzing transients and accidents. The advanced kinetics models have also been implemented into KIN3D, a module of the VARIANT/TGV code (stand-alone neutron kinetics) for broadening application and for testing and benchmarking. In the paper, a short review of the SIMMER and KIN3D neutron kinetics models is given. Some typical transients related to ADS perturbations are analyzed. The general models of SIMMER and KIN3D are compared with more simple techniques developed in the context of this work to get a better understanding of the specifics of transients in subcritical systems and to estimate the performance of different kinetics options. These comparisons may also help in elaborating new kinetics models and extending existing computation tools for ADS transient analyses. The traditional point-kinetics model may give rather inaccurate transient reaction rate distributions in an ADS even if the material configuration does not change significantly. This inaccuracy is not related to the problem of choosing a 'right' weighting function: the point-kinetics model with any weighting function cannot take into account pronounced flux shape variations related to possible significant changes in the criticality level or to fast beam trips. To improve the accuracy of the point-kinetics option for slow transients, we have introduced a correction factor technique. The related analyses give a better understanding of 'long-timescale' kinetics phenomena in the subcritical domain and help to evaluate the performance of the quasi-static scheme in a particular case. One

  9. Model tests on dynamic performance of RC shear walls

    International Nuclear Information System (INIS)

    Nagashima, Toshio; Shibata, Akenori; Inoue, Norio; Muroi, Kazuo.

    1991-01-01

    For the inelastic dynamic response analysis of a reactor building subjected to earthquakes, it is essentially important to properly evaluate its restoring force characteristics under dynamic loading condition and its damping performance. Reinforced concrete shear walls are the main structural members of a reactor building, and dominate its seismic behavior. In order to obtain the basic information on the dynamic restoring force characteristics and damping performance of shear walls, the dynamic test using a large shaking table, static displacement control test and the pseudo-dynamic test on the models of a shear wall were conducted. In the dynamic test, four specimens were tested on a large shaking table. In the static test, four specimens were tested, and in the pseudo-dynamic test, three specimens were tested. These tests are outlined. The results of these tests were compared, placing emphasis on the restoring force characteristics and damping performance of the RC wall models. The strength was higher in the dynamic test models than in the static test models mainly due to the effect of loading rate. (K.I.)

  10. A Practical Model to Perform Comprehensive Cybersecurity Audits

    Directory of Open Access Journals (Sweden)

    Regner Sabillon

    2018-03-01

    Full Text Available These days organizations are continually facing being targets of cyberattacks and cyberthreats; the sophistication and complexity of modern cyberattacks and the modus operandi of cybercriminals including Techniques, Tactics and Procedures (TTP keep growing at unprecedented rates. Cybercriminals are always adopting new strategies to plan and launch cyberattacks based on existing cybersecurity vulnerabilities and exploiting end users by using social engineering techniques. Cybersecurity audits are extremely important to verify that information security controls are in place and to detect weaknesses of inexistent cybersecurity or obsolete controls. This article presents an innovative and comprehensive cybersecurity audit model. The CyberSecurity Audit Model (CSAM can be implemented to perform internal or external cybersecurity audits. This model can be used to perform single cybersecurity audits or can be part of any corporate audit program to improve cybersecurity controls. Any information security or cybersecurity audit team has either the options to perform a full audit for all cybersecurity domains or by selecting specific domains to audit certain areas that need control verification and hardening. The CSAM has 18 domains; Domain 1 is specific for Nation States and Domains 2-18 can be implemented at any organization. The organization can be any small, medium or large enterprise, the model is also applicable to any Non-Profit Organization (NPO.

  11. Instruction-level performance modeling and characterization of multimedia applications

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Los Alamos National Lab., NM (United States). Scientific Computing Group; Cameron, K.W. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Computer Science

    1999-06-01

    One of the challenges for characterizing and modeling realistic multimedia applications is the lack of access to source codes. On-chip performance counters effectively resolve this problem by monitoring run-time behaviors at the instruction-level. This paper presents a novel technique of characterizing and modeling workloads at the instruction level for realistic multimedia applications using hardware performance counters. A variety of instruction counts are collected from some multimedia applications, such as RealPlayer, GSM Vocoder, MPEG encoder/decoder, and speech synthesizer. These instruction counts can be used to form a set of abstract characteristic parameters directly related to a processor`s architectural features. Based on microprocessor architectural constraints and these calculated abstract parameters, the architectural performance bottleneck for a specific application can be estimated. Meanwhile, the bottleneck estimation can provide suggestions about viable architectural/functional improvement for certain workloads. The biggest advantage of this new characterization technique is a better understanding of processor utilization efficiency and architectural bottleneck for each application. This technique also provides predictive insight of future architectural enhancements and their affect on current codes. In this paper the authors also attempt to model architectural effect on processor utilization without memory influence. They derive formulas for calculating CPI{sub 0}, CPI without memory effect, and they quantify utilization of architectural parameters. These equations are architecturally diagnostic and predictive in nature. Results provide promise in code characterization, and empirical/analytical modeling.

  12. Integrated healthcare networks' performance: a growth curve modeling approach.

    Science.gov (United States)

    Wan, Thomas T H; Wang, Bill B L

    2003-05-01

    This study examines the effects of integration on the performance ratings of the top 100 integrated healthcare networks (IHNs) in the United States. A strategic-contingency theory is used to identify the relationship of IHNs' performance to their structural and operational characteristics and integration strategies. To create a database for the panel study, the top 100 IHNs selected by the SMG Marketing Group in 1998 were followed up in 1999 and 2000. The data were merged with the Dorenfest data on information system integration. A growth curve model was developed and validated by the Mplus statistical program. Factors influencing the top 100 IHNs' performance in 1998 and their subsequent rankings in the consecutive years were analyzed. IHNs' initial performance scores were positively influenced by network size, number of affiliated physicians and profit margin, and were negatively associated with average length of stay and technical efficiency. The continuing high performance, judged by maintaining higher performance scores, tended to be enhanced by the use of more managerial or executive decision-support systems. Future studies should include time-varying operational indicators to serve as predictors of network performance.

  13. The predictive performance and stability of six species distribution models.

    Directory of Open Access Journals (Sweden)

    Ren-Yan Duan

    Full Text Available Predicting species' potential geographical range by species distribution models (SDMs is central to understand their ecological requirements. However, the effects of using different modeling techniques need further investigation. In order to improve the prediction effect, we need to assess the predictive performance and stability of different SDMs.We collected the distribution data of five common tree species (Pinus massoniana, Betula platyphylla, Quercus wutaishanica, Quercus mongolica and Quercus variabilis and simulated their potential distribution area using 13 environmental variables and six widely used SDMs: BIOCLIM, DOMAIN, MAHAL, RF, MAXENT, and SVM. Each model run was repeated 100 times (trials. We compared the predictive performance by testing the consistency between observations and simulated distributions and assessed the stability by the standard deviation, coefficient of variation, and the 99% confidence interval of Kappa and AUC values.The mean values of AUC and Kappa from MAHAL, RF, MAXENT, and SVM trials were similar and significantly higher than those from BIOCLIM and DOMAIN trials (p<0.05, while the associated standard deviations and coefficients of variation were larger for BIOCLIM and DOMAIN trials (p<0.05, and the 99% confidence intervals for AUC and Kappa values were narrower for MAHAL, RF, MAXENT, and SVM. Compared to BIOCLIM and DOMAIN, other SDMs (MAHAL, RF, MAXENT, and SVM had higher prediction accuracy, smaller confidence intervals, and were more stable and less affected by the random variable (randomly selected pseudo-absence points.According to the prediction performance and stability of SDMs, we can divide these six SDMs into two categories: a high performance and stability group including MAHAL, RF, MAXENT, and SVM, and a low performance and stability group consisting of BIOCLIM, and DOMAIN. We highlight that choosing appropriate SDMs to address a specific problem is an important part of the modeling process.

  14. Hybrid Building Performance Simulation Models for Industrial Energy Efficiency Applications

    Directory of Open Access Journals (Sweden)

    Peter Smolek

    2018-06-01

    Full Text Available In the challenge of achieving environmental sustainability, industrial production plants, as large contributors to the overall energy demand of a country, are prime candidates for applying energy efficiency measures. A modelling approach using cubes is used to decompose a production facility into manageable modules. All aspects of the facility are considered, classified into the building, energy system, production and logistics. This approach leads to specific challenges for building performance simulations since all parts of the facility are highly interconnected. To meet this challenge, models for the building, thermal zones, energy converters and energy grids are presented and the interfaces to the production and logistics equipment are illustrated. The advantages and limitations of the chosen approach are discussed. In an example implementation, the feasibility of the approach and models is shown. Different scenarios are simulated to highlight the models and the results are compared.

  15. Fracture modelling of a high performance armour steel

    Science.gov (United States)

    Skoglund, P.; Nilsson, M.; Tjernberg, A.

    2006-08-01

    The fracture characteristics of the high performance armour steel Armox 500T is investigated. Tensile mechanical experiments using samples with different notch geometries are used to investigate the effect of multi-axial stress states on the strain to fracture. The experiments are numerically simulated and from the simulation the stress at the point of fracture initiation is determined as a function of strain and these data are then used to extract parameters for fracture models. A fracture model based on quasi-static experiments is suggested and the model is tested against independent experiments done at both static and dynamic loading. The result show that the fracture model give reasonable good agreement between simulations and experiments at both static and dynamic loading condition. This indicates that multi-axial loading is more important to the strain to fracture than the deformation rate in the investigated loading range. However on-going work will further characterise the fracture behaviour of Armox 500T.

  16. Modeling the Performance of Fast Mulipole Method on HPC platforms

    KAUST Repository

    Ibeid, Huda

    2012-04-06

    The current trend in high performance computing is pushing towards exascale computing. To achieve this exascale performance, future systems will have between 100 million and 1 billion cores assuming gigahertz cores. Currently, there are many efforts studying the hardware and software bottlenecks for building an exascale system. It is important to understand and meet these bottlenecks in order to attain 10 PFLOPS performance. On applications side, there is an urgent need to model application performance and to understand what changes need to be made to ensure continued scalability at this scale. Fast multipole methods (FMM) were originally developed for accelerating N-body problems for particle based methods. Nowadays, FMM is more than an N-body solver, recent trends in HPC have been to use FMMs in unconventional application areas. FMM is likely to be a main player in exascale due to its hierarchical nature and the techniques used to access the data via a tree structure which allow many operations to happen simultaneously at each level of the hierarchy. In this thesis , we discuss the challenges for FMM on current parallel computers and future exasclae architecture. Furthermore, we develop a novel performance model for FMM. Our ultimate aim of this thesis is to ensure the scalability of FMM on the future exascale machines.

  17. 3D Massive MIMO Systems: Channel Modeling and Performance Analysis

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-03-01

    Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. More recently, the trend is to enhance the system performance by exploiting the channel\\'s degrees of freedom in the elevation through the dynamic adaptation of the vertical antenna beam pattern. This necessitates the derivation and characterization of three-dimensional (3D) channels. Over the years, channel models have evolved to address the challenges of wireless communication technologies. In parallel to theoretical studies on channel modeling, many standardized channel models like COST-based models, 3GPP SCM, WINNER, ITU have emerged that act as references for industries and telecommunication companies to assess system-level and link-level performances of advanced signal processing techniques over real-like channels. Given the existing channels are only two dimensional (2D) in nature; a large effort in channel modeling is needed to study the impact of the channel component in the elevation direction. The first part of this work sheds light on the current 3GPP activity around 3D channel modeling and beamforming, an aspect that to our knowledge has not been extensively covered by a research publication. The standardized MIMO channel model is presented, that incorporates both the propagation effects of the environment and the radio effects of the antennas. In order to facilitate future studies on the use of 3D beamforming, the main features of the proposed 3D channel model are discussed. A brief overview of the future 3GPP 3D channel model being outlined for the next generation of wireless networks is also provided. In the subsequent part of this work, we present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles of departure and

  18. Compact models and performance investigations for subthreshold interconnects

    CERN Document Server

    Dhiman, Rohit

    2014-01-01

    The book provides a detailed analysis of issues related to sub-threshold interconnect performance from the perspective of analytical approach and design techniques. Particular emphasis is laid on the performance analysis of coupling noise and variability issues in sub-threshold domain to develop efficient compact models. The proposed analytical approach gives physical insight of the parameters affecting the transient behavior of coupled interconnects. Remedial design techniques are also suggested to mitigate the effect of coupling noise. The effects of wire width, spacing between the wires, wi

  19. Performance prediction of industrial centrifuges using scale-down models.

    Science.gov (United States)

    Boychyn, M; Yim, S S S; Bulmer, M; More, J; Bracewell, D G; Hoare, M

    2004-12-01

    Computational fluid dynamics was used to model the high flow forces found in the feed zone of a multichamber-bowl centrifuge and reproduce these in a small, high-speed rotating disc device. Linking the device to scale-down centrifugation, permitted good estimation of the performance of various continuous-flow centrifuges (disc stack, multichamber bowl, CARR Powerfuge) for shear-sensitive protein precipitates. Critically, the ultra scale-down centrifugation process proved to be a much more accurate predictor of production multichamber-bowl performance than was the pilot centrifuge.

  20. Performance of the general circulation models in simulating temperature and precipitation over Iran

    Science.gov (United States)

    Abbasian, Mohammadsadegh; Moghim, Sanaz; Abrishamchi, Ahmad

    2018-03-01

    General Circulation Models (GCMs) are advanced tools for impact assessment and climate change studies. Previous studies show that the performance of the GCMs in simulating climate variables varies significantly over different regions. This study intends to evaluate the performance of the Coupled Model Intercomparison Project phase 5 (CMIP5) GCMs in simulating temperature and precipitation over Iran. Simulations from 37 GCMs and observations from the Climatic Research Unit (CRU) were obtained for the period of 1901-2005. Six measures of performance including mean bias, root mean square error (RMSE), Nash-Sutcliffe efficiency (NSE), linear correlation coefficient (r), Kolmogorov-Smirnov statistic (KS), Sen's slope estimator, and the Taylor diagram are used for the evaluation. GCMs are ranked based on each statistic at seasonal and annual time scales. Results show that most GCMs perform reasonably well in simulating the annual and seasonal temperature over Iran. The majority of the GCMs have a poor skill to simulate precipitation, particularly at seasonal scale. Based on the results, the best GCMs to represent temperature and precipitation simulations over Iran are the CMCC-CMS (Euro-Mediterranean Center on Climate Change) and the MRI-CGCM3 (Meteorological Research Institute), respectively. The results are valuable for climate and hydrometeorological studies and can help water resources planners and managers to choose the proper GCM based on their criteria.